eb6d21b4ca
Subversion is being difficult here so take a hammer and get it in. MFC after: 2 weeks Security: CVE-2009-3563
4190 lines
115 KiB
C
4190 lines
115 KiB
C
/*
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* ntp_crypto.c - NTP version 4 public key routines
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#ifdef OPENSSL
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include "ntpd.h"
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#include "ntp_stdlib.h"
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#include "ntp_unixtime.h"
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#include "ntp_string.h"
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#include <ntp_random.h>
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#include "openssl/asn1_mac.h"
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#include "openssl/bn.h"
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#include "openssl/err.h"
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#include "openssl/evp.h"
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#include "openssl/pem.h"
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#include "openssl/rand.h"
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#include "openssl/x509v3.h"
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#ifdef KERNEL_PLL
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#include "ntp_syscall.h"
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#endif /* KERNEL_PLL */
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/*
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* Extension field message format
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*
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* These are always signed and saved before sending in network byte
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* order. They must be converted to and from host byte order for
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* processing.
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*
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* +-------+-------+
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* | op | len | <- extension pointer
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* +-------+-------+
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* | assocID |
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* +---------------+
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* | timestamp | <- value pointer
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* +---------------+
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* | filestamp |
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* +---------------+
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* | value len |
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* +---------------+
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* | |
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* = value =
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* | |
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* +---------------+
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* | signature len |
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* +---------------+
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* | |
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* = signature =
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* | |
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* +---------------+
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*
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* The CRYPTO_RESP bit is set to 0 for requests, 1 for responses.
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* Requests carry the association ID of the receiver; responses carry
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* the association ID of the sender. Some messages include only the
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* operation/length and association ID words and so have length 8
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* octets. Ohers include the value structure and associated value and
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* signature fields. These messages include the timestamp, filestamp,
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* value and signature words and so have length at least 24 octets. The
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* signature and/or value fields can be empty, in which case the
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* respective length words are zero. An empty value with nonempty
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* signature is syntactically valid, but semantically questionable.
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*
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* The filestamp represents the time when a cryptographic data file such
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* as a public/private key pair is created. It follows every reference
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* depending on that file and serves as a means to obsolete earlier data
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* of the same type. The timestamp represents the time when the
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* cryptographic data of the message were last signed. Creation of a
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* cryptographic data file or signing a message can occur only when the
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* creator or signor is synchronized to an authoritative source and
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* proventicated to a trusted authority.
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*
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* Note there are four conditions required for server trust. First, the
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* public key on the certificate must be verified, which involves a
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* number of format, content and consistency checks. Next, the server
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* identity must be confirmed by one of four schemes: private
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* certificate, IFF scheme, GQ scheme or certificate trail hike to a
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* self signed trusted certificate. Finally, the server signature must
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* be verified.
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*/
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/*
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* Cryptodefines
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*/
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#define TAI_1972 10 /* initial TAI offset (s) */
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#define MAX_LEAP 100 /* max UTC leapseconds (s) */
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#define VALUE_LEN (6 * 4) /* min response field length */
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#define YEAR (60 * 60 * 24 * 365) /* seconds in year */
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/*
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* Global cryptodata in host byte order
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*/
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u_int32 crypto_flags = 0x0; /* status word */
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/*
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* Global cryptodata in network byte order
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*/
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struct cert_info *cinfo = NULL; /* certificate info/value */
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struct value hostval; /* host value */
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struct value pubkey; /* public key */
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struct value tai_leap; /* leapseconds table */
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EVP_PKEY *iffpar_pkey = NULL; /* IFF parameters */
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EVP_PKEY *gqpar_pkey = NULL; /* GQ parameters */
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EVP_PKEY *mvpar_pkey = NULL; /* MV parameters */
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char *iffpar_file = NULL; /* IFF parameters file */
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char *gqpar_file = NULL; /* GQ parameters file */
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char *mvpar_file = NULL; /* MV parameters file */
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/*
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* Private cryptodata in host byte order
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*/
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static char *passwd = NULL; /* private key password */
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static EVP_PKEY *host_pkey = NULL; /* host key */
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static EVP_PKEY *sign_pkey = NULL; /* sign key */
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static const EVP_MD *sign_digest = NULL; /* sign digest */
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static u_int sign_siglen; /* sign key length */
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static char *rand_file = NULL; /* random seed file */
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static char *host_file = NULL; /* host key file */
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static char *sign_file = NULL; /* sign key file */
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static char *cert_file = NULL; /* certificate file */
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static char *leap_file = NULL; /* leapseconds file */
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static tstamp_t if_fstamp = 0; /* IFF filestamp */
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static tstamp_t gq_fstamp = 0; /* GQ file stamp */
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static tstamp_t mv_fstamp = 0; /* MV filestamp */
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static u_int ident_scheme = 0; /* server identity scheme */
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/*
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* Cryptotypes
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*/
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static int crypto_verify P((struct exten *, struct value *,
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struct peer *));
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static int crypto_encrypt P((struct exten *, struct value *,
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keyid_t *));
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static int crypto_alice P((struct peer *, struct value *));
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static int crypto_alice2 P((struct peer *, struct value *));
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static int crypto_alice3 P((struct peer *, struct value *));
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static int crypto_bob P((struct exten *, struct value *));
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static int crypto_bob2 P((struct exten *, struct value *));
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static int crypto_bob3 P((struct exten *, struct value *));
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static int crypto_iff P((struct exten *, struct peer *));
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static int crypto_gq P((struct exten *, struct peer *));
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static int crypto_mv P((struct exten *, struct peer *));
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static u_int crypto_send P((struct exten *, struct value *));
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static tstamp_t crypto_time P((void));
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static u_long asn2ntp P((ASN1_TIME *));
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static struct cert_info *cert_parse P((u_char *, u_int, tstamp_t));
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static int cert_sign P((struct exten *, struct value *));
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static int cert_valid P((struct cert_info *, EVP_PKEY *));
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static int cert_install P((struct exten *, struct peer *));
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static void cert_free P((struct cert_info *));
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static EVP_PKEY *crypto_key P((char *, tstamp_t *));
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static int bighash P((BIGNUM *, BIGNUM *));
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static struct cert_info *crypto_cert P((char *));
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static void crypto_tai P((char *));
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#ifdef SYS_WINNT
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int
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readlink(char * link, char * file, int len) {
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return (-1);
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}
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#endif
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/*
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* session_key - generate session key
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*
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* This routine generates a session key from the source address,
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* destination address, key ID and private value. The value of the
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* session key is the MD5 hash of these values, while the next key ID is
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* the first four octets of the hash.
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*
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* Returns the next key ID
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*/
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keyid_t
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session_key(
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struct sockaddr_storage *srcadr, /* source address */
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struct sockaddr_storage *dstadr, /* destination address */
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keyid_t keyno, /* key ID */
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keyid_t private, /* private value */
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u_long lifetime /* key lifetime */
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)
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{
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EVP_MD_CTX ctx; /* message digest context */
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u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
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keyid_t keyid; /* key identifer */
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u_int32 header[10]; /* data in network byte order */
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u_int hdlen, len;
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if (!dstadr)
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return 0;
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/*
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* Generate the session key and key ID. If the lifetime is
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* greater than zero, install the key and call it trusted.
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*/
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hdlen = 0;
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switch(srcadr->ss_family) {
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case AF_INET:
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header[0] = ((struct sockaddr_in *)srcadr)->sin_addr.s_addr;
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header[1] = ((struct sockaddr_in *)dstadr)->sin_addr.s_addr;
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header[2] = htonl(keyno);
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header[3] = htonl(private);
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hdlen = 4 * sizeof(u_int32);
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break;
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case AF_INET6:
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memcpy(&header[0], &GET_INADDR6(*srcadr),
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sizeof(struct in6_addr));
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memcpy(&header[4], &GET_INADDR6(*dstadr),
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sizeof(struct in6_addr));
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header[8] = htonl(keyno);
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header[9] = htonl(private);
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hdlen = 10 * sizeof(u_int32);
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break;
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}
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EVP_DigestInit(&ctx, EVP_md5());
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EVP_DigestUpdate(&ctx, (u_char *)header, hdlen);
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EVP_DigestFinal(&ctx, dgst, &len);
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memcpy(&keyid, dgst, 4);
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keyid = ntohl(keyid);
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if (lifetime != 0) {
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MD5auth_setkey(keyno, dgst, len);
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authtrust(keyno, lifetime);
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}
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#ifdef DEBUG
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if (debug > 1)
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printf(
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"session_key: %s > %s %08x %08x hash %08x life %lu\n",
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stoa(srcadr), stoa(dstadr), keyno,
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private, keyid, lifetime);
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#endif
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return (keyid);
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}
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/*
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* make_keylist - generate key list
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*
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* Returns
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* XEVNT_OK success
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* XEVNT_PER host certificate expired
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*
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* This routine constructs a pseudo-random sequence by repeatedly
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* hashing the session key starting from a given source address,
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* destination address, private value and the next key ID of the
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* preceeding session key. The last entry on the list is saved along
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* with its sequence number and public signature.
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*/
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int
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make_keylist(
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struct peer *peer, /* peer structure pointer */
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struct interface *dstadr /* interface */
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)
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{
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EVP_MD_CTX ctx; /* signature context */
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tstamp_t tstamp; /* NTP timestamp */
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struct autokey *ap; /* autokey pointer */
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struct value *vp; /* value pointer */
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keyid_t keyid = 0; /* next key ID */
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keyid_t cookie; /* private value */
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u_long lifetime;
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u_int len, mpoll;
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int i;
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if (!dstadr)
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return XEVNT_OK;
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/*
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* Allocate the key list if necessary.
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*/
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tstamp = crypto_time();
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if (peer->keylist == NULL)
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peer->keylist = emalloc(sizeof(keyid_t) *
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NTP_MAXSESSION);
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/*
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* Generate an initial key ID which is unique and greater than
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* NTP_MAXKEY.
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*/
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while (1) {
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keyid = (ntp_random() + NTP_MAXKEY + 1) & ((1 <<
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sizeof(keyid_t)) - 1);
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if (authhavekey(keyid))
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continue;
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break;
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}
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/*
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* Generate up to NTP_MAXSESSION session keys. Stop if the
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* next one would not be unique or not a session key ID or if
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* it would expire before the next poll. The private value
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* included in the hash is zero if broadcast mode, the peer
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* cookie if client mode or the host cookie if symmetric modes.
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*/
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mpoll = 1 << min(peer->ppoll, peer->hpoll);
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lifetime = min(sys_automax, NTP_MAXSESSION * mpoll);
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if (peer->hmode == MODE_BROADCAST)
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cookie = 0;
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else
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cookie = peer->pcookie;
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for (i = 0; i < NTP_MAXSESSION; i++) {
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peer->keylist[i] = keyid;
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peer->keynumber = i;
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keyid = session_key(&dstadr->sin, &peer->srcadr, keyid,
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cookie, lifetime);
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lifetime -= mpoll;
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if (auth_havekey(keyid) || keyid <= NTP_MAXKEY ||
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lifetime <= mpoll)
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break;
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}
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/*
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* Save the last session key ID, sequence number and timestamp,
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* then sign these values for later retrieval by the clients. Be
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* careful not to use invalid key media. Use the public values
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* timestamp as filestamp.
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*/
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vp = &peer->sndval;
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if (vp->ptr == NULL)
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vp->ptr = emalloc(sizeof(struct autokey));
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ap = (struct autokey *)vp->ptr;
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ap->seq = htonl(peer->keynumber);
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ap->key = htonl(keyid);
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vp->tstamp = htonl(tstamp);
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vp->fstamp = hostval.tstamp;
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vp->vallen = htonl(sizeof(struct autokey));
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vp->siglen = 0;
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if (tstamp != 0) {
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if (tstamp < cinfo->first || tstamp > cinfo->last)
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return (XEVNT_PER);
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if (vp->sig == NULL)
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vp->sig = emalloc(sign_siglen);
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EVP_SignInit(&ctx, sign_digest);
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EVP_SignUpdate(&ctx, (u_char *)vp, 12);
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EVP_SignUpdate(&ctx, vp->ptr, sizeof(struct autokey));
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if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
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vp->siglen = htonl(len);
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else
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msyslog(LOG_ERR, "make_keys %s\n",
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ERR_error_string(ERR_get_error(), NULL));
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peer->flags |= FLAG_ASSOC;
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}
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#ifdef DEBUG
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if (debug)
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printf("make_keys: %d %08x %08x ts %u fs %u poll %d\n",
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ntohl(ap->seq), ntohl(ap->key), cookie,
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ntohl(vp->tstamp), ntohl(vp->fstamp), peer->hpoll);
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#endif
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return (XEVNT_OK);
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}
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/*
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* crypto_recv - parse extension fields
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*
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* This routine is called when the packet has been matched to an
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* association and passed sanity, format and MAC checks. We believe the
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* extension field values only if the field has proper format and
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* length, the timestamp and filestamp are valid and the signature has
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* valid length and is verified. There are a few cases where some values
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* are believed even if the signature fails, but only if the proventic
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* bit is not set.
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*/
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int
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crypto_recv(
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struct peer *peer, /* peer structure pointer */
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struct recvbuf *rbufp /* packet buffer pointer */
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)
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{
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const EVP_MD *dp; /* message digest algorithm */
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u_int32 *pkt; /* receive packet pointer */
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struct autokey *ap, *bp; /* autokey pointer */
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struct exten *ep, *fp; /* extension pointers */
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int has_mac; /* length of MAC field */
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int authlen; /* offset of MAC field */
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associd_t associd; /* association ID */
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tstamp_t tstamp = 0; /* timestamp */
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tstamp_t fstamp = 0; /* filestamp */
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u_int len; /* extension field length */
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u_int code; /* extension field opcode */
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u_int vallen = 0; /* value length */
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X509 *cert; /* X509 certificate */
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char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
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keyid_t cookie; /* crumbles */
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int hismode; /* packet mode */
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int rval = XEVNT_OK;
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u_char *ptr;
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u_int32 temp32;
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/*
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* Initialize. Note that the packet has already been checked for
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* valid format and extension field lengths. First extract the
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* field length, command code and association ID in host byte
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* order. These are used with all commands and modes. Then check
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* the version number, which must be 2, and length, which must
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* be at least 8 for requests and VALUE_LEN (24) for responses.
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* Packets that fail either test sink without a trace. The
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* association ID is saved only if nonzero.
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*/
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authlen = LEN_PKT_NOMAC;
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hismode = (int)PKT_MODE((&rbufp->recv_pkt)->li_vn_mode);
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while ((has_mac = rbufp->recv_length - authlen) > MAX_MAC_LEN) {
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pkt = (u_int32 *)&rbufp->recv_pkt + authlen / 4;
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ep = (struct exten *)pkt;
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code = ntohl(ep->opcode) & 0xffff0000;
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len = ntohl(ep->opcode) & 0x0000ffff;
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associd = (associd_t) ntohl(pkt[1]);
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rval = XEVNT_OK;
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#ifdef DEBUG
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if (debug)
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printf(
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"crypto_recv: flags 0x%x ext offset %d len %u code 0x%x assocID %d\n",
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peer->crypto, authlen, len, code >> 16,
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associd);
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#endif
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/*
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* Check version number and field length. If bad,
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* quietly ignore the packet.
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*/
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if (((code >> 24) & 0x3f) != CRYPTO_VN || len < 8) {
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sys_unknownversion++;
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code |= CRYPTO_ERROR;
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}
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/*
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* Little vulnerability bandage here. If a perp tosses a
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* fake association ID over the fence, we better toss it
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* out. Only the first one counts.
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*/
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if (code & CRYPTO_RESP) {
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if (peer->assoc == 0)
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peer->assoc = associd;
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else if (peer->assoc != associd)
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code |= CRYPTO_ERROR;
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}
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if (len >= VALUE_LEN) {
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tstamp = ntohl(ep->tstamp);
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fstamp = ntohl(ep->fstamp);
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vallen = ntohl(ep->vallen);
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}
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switch (code) {
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|
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/*
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* Install status word, host name, signature scheme and
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* association ID. In OpenSSL the signature algorithm is
|
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* bound to the digest algorithm, so the NID completely
|
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* defines the signature scheme. Note the request and
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* response are identical, but neither is validated by
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* signature. The request is processed here only in
|
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* symmetric modes. The server name field might be
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* useful to implement access controls in future.
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*/
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case CRYPTO_ASSOC:
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|
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/*
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* If the machine is running when this message
|
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* arrives, the other fellow has reset and so
|
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* must we. Otherwise, pass the extension field
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* to the transmit side.
|
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*/
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if (peer->crypto) {
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rval = XEVNT_ERR;
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break;
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}
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fp = emalloc(len);
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memcpy(fp, ep, len);
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temp32 = CRYPTO_RESP;
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fp->opcode |= htonl(temp32);
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peer->cmmd = fp;
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/* fall through */
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|
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case CRYPTO_ASSOC | CRYPTO_RESP:
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/*
|
|
* Discard the message if it has already been
|
|
* stored or the message has been amputated.
|
|
*/
|
|
if (peer->crypto)
|
|
break;
|
|
|
|
if (vallen == 0 || vallen > MAXHOSTNAME ||
|
|
len < VALUE_LEN + vallen) {
|
|
rval = XEVNT_LEN;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Check the identity schemes are compatible. If
|
|
* the client has PC, the server must have PC,
|
|
* in which case the server public key and
|
|
* identity are presumed valid, so we skip the
|
|
* certificate and identity exchanges and move
|
|
* immediately to the cookie exchange which
|
|
* confirms the server signature.
|
|
*/
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf(
|
|
"crypto_recv: ident host 0x%x server 0x%x\n",
|
|
crypto_flags, fstamp);
|
|
#endif
|
|
temp32 = (crypto_flags | ident_scheme) &
|
|
fstamp & CRYPTO_FLAG_MASK;
|
|
if (crypto_flags & CRYPTO_FLAG_PRIV) {
|
|
if (!(fstamp & CRYPTO_FLAG_PRIV)) {
|
|
rval = XEVNT_KEY;
|
|
break;
|
|
|
|
} else {
|
|
fstamp |= CRYPTO_FLAG_VALID |
|
|
CRYPTO_FLAG_VRFY |
|
|
CRYPTO_FLAG_SIGN;
|
|
}
|
|
/*
|
|
* In symmetric modes it is an error if either
|
|
* peer requests identity and the other peer
|
|
* does not support it.
|
|
*/
|
|
} else if ((hismode == MODE_ACTIVE || hismode ==
|
|
MODE_PASSIVE) && ((crypto_flags | fstamp) &
|
|
CRYPTO_FLAG_MASK) && !temp32) {
|
|
rval = XEVNT_KEY;
|
|
break;
|
|
/*
|
|
* It is an error if the client requests
|
|
* identity and the server does not support it.
|
|
*/
|
|
} else if (hismode == MODE_CLIENT && (fstamp &
|
|
CRYPTO_FLAG_MASK) && !temp32) {
|
|
rval = XEVNT_KEY;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Otherwise, the identity scheme(s) are those
|
|
* that both client and server support.
|
|
*/
|
|
fstamp = temp32 | (fstamp & ~CRYPTO_FLAG_MASK);
|
|
|
|
/*
|
|
* Discard the message if the signature digest
|
|
* NID is not supported.
|
|
*/
|
|
temp32 = (fstamp >> 16) & 0xffff;
|
|
dp =
|
|
(const EVP_MD *)EVP_get_digestbynid(temp32);
|
|
if (dp == NULL) {
|
|
rval = XEVNT_MD;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Save status word, host name and message
|
|
* digest/signature type.
|
|
*/
|
|
peer->crypto = fstamp;
|
|
peer->digest = dp;
|
|
peer->subject = emalloc(vallen + 1);
|
|
memcpy(peer->subject, ep->pkt, vallen);
|
|
peer->subject[vallen] = '\0';
|
|
peer->issuer = emalloc(vallen + 1);
|
|
strcpy(peer->issuer, peer->subject);
|
|
temp32 = (fstamp >> 16) & 0xffff;
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"flags 0x%x host %s signature %s", fstamp,
|
|
peer->subject, OBJ_nid2ln(temp32));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* Decode X509 certificate in ASN.1 format and extract
|
|
* the data containing, among other things, subject
|
|
* name and public key. In the default identification
|
|
* scheme, the certificate trail is followed to a self
|
|
* signed trusted certificate.
|
|
*/
|
|
case CRYPTO_CERT | CRYPTO_RESP:
|
|
|
|
/*
|
|
* Discard the message if invalid.
|
|
*/
|
|
if ((rval = crypto_verify(ep, NULL, peer)) !=
|
|
XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* Scan the certificate list to delete old
|
|
* versions and link the newest version first on
|
|
* the list.
|
|
*/
|
|
if ((rval = cert_install(ep, peer)) != XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* If we snatch the certificate before the
|
|
* server certificate has been signed by its
|
|
* server, it will be self signed. When it is,
|
|
* we chase the certificate issuer, which the
|
|
* server has, and keep going until a self
|
|
* signed trusted certificate is found. Be sure
|
|
* to update the issuer field, since it may
|
|
* change.
|
|
*/
|
|
if (peer->issuer != NULL)
|
|
free(peer->issuer);
|
|
peer->issuer = emalloc(strlen(cinfo->issuer) +
|
|
1);
|
|
strcpy(peer->issuer, cinfo->issuer);
|
|
|
|
/*
|
|
* We plug in the public key and lifetime from
|
|
* the first certificate received. However, note
|
|
* that this certificate might not be signed by
|
|
* the server, so we can't check the
|
|
* signature/digest NID.
|
|
*/
|
|
if (peer->pkey == NULL) {
|
|
ptr = (u_char *)cinfo->cert.ptr;
|
|
cert = d2i_X509(NULL, &ptr,
|
|
ntohl(cinfo->cert.vallen));
|
|
peer->pkey = X509_get_pubkey(cert);
|
|
X509_free(cert);
|
|
}
|
|
peer->flash &= ~TEST8;
|
|
temp32 = cinfo->nid;
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"cert %s 0x%x %s (%u) fs %u",
|
|
cinfo->subject, cinfo->flags,
|
|
OBJ_nid2ln(temp32), temp32,
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* Schnorr (IFF)identity scheme. This scheme is designed
|
|
* for use with shared secret group keys and where the
|
|
* certificate may be generated by a third party. The
|
|
* client sends a challenge to the server, which
|
|
* performs a calculation and returns the result. A
|
|
* positive result is possible only if both client and
|
|
* server contain the same secret group key.
|
|
*/
|
|
case CRYPTO_IFF | CRYPTO_RESP:
|
|
|
|
/*
|
|
* Discard the message if invalid or certificate
|
|
* trail not trusted.
|
|
*/
|
|
if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_verify(ep, NULL, peer)) !=
|
|
XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* If the the challenge matches the response,
|
|
* the certificate public key, as well as the
|
|
* server public key, signatyre and identity are
|
|
* all verified at the same time. The server is
|
|
* declared trusted, so we skip further
|
|
* certificate stages and move immediately to
|
|
* the cookie stage.
|
|
*/
|
|
if ((rval = crypto_iff(ep, peer)) != XEVNT_OK)
|
|
break;
|
|
|
|
peer->crypto |= CRYPTO_FLAG_VRFY |
|
|
CRYPTO_FLAG_PROV;
|
|
peer->flash &= ~TEST8;
|
|
snprintf(statstr, NTP_MAXSTRLEN, "iff fs %u",
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* Guillou-Quisquater (GQ) identity scheme. This scheme
|
|
* is designed for use with public certificates carrying
|
|
* the GQ public key in an extension field. The client
|
|
* sends a challenge to the server, which performs a
|
|
* calculation and returns the result. A positive result
|
|
* is possible only if both client and server contain
|
|
* the same group key and the server has the matching GQ
|
|
* private key.
|
|
*/
|
|
case CRYPTO_GQ | CRYPTO_RESP:
|
|
|
|
/*
|
|
* Discard the message if invalid or certificate
|
|
* trail not trusted.
|
|
*/
|
|
if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_verify(ep, NULL, peer)) !=
|
|
XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* If the the challenge matches the response,
|
|
* the certificate public key, as well as the
|
|
* server public key, signatyre and identity are
|
|
* all verified at the same time. The server is
|
|
* declared trusted, so we skip further
|
|
* certificate stages and move immediately to
|
|
* the cookie stage.
|
|
*/
|
|
if ((rval = crypto_gq(ep, peer)) != XEVNT_OK)
|
|
break;
|
|
|
|
peer->crypto |= CRYPTO_FLAG_VRFY |
|
|
CRYPTO_FLAG_PROV;
|
|
peer->flash &= ~TEST8;
|
|
snprintf(statstr, NTP_MAXSTRLEN, "gq fs %u",
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* MV
|
|
*/
|
|
case CRYPTO_MV | CRYPTO_RESP:
|
|
|
|
/*
|
|
* Discard the message if invalid or certificate
|
|
* trail not trusted.
|
|
*/
|
|
if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_verify(ep, NULL, peer)) !=
|
|
XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* If the the challenge matches the response,
|
|
* the certificate public key, as well as the
|
|
* server public key, signatyre and identity are
|
|
* all verified at the same time. The server is
|
|
* declared trusted, so we skip further
|
|
* certificate stages and move immediately to
|
|
* the cookie stage.
|
|
*/
|
|
if ((rval = crypto_mv(ep, peer)) != XEVNT_OK)
|
|
break;
|
|
|
|
peer->crypto |= CRYPTO_FLAG_VRFY |
|
|
CRYPTO_FLAG_PROV;
|
|
peer->flash &= ~TEST8;
|
|
snprintf(statstr, NTP_MAXSTRLEN, "mv fs %u",
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* Cookie request in symmetric modes. Roll a random
|
|
* cookie and install in symmetric mode. Encrypt for the
|
|
* response, which is transmitted later.
|
|
*/
|
|
case CRYPTO_COOK:
|
|
|
|
/*
|
|
* Discard the message if invalid or certificate
|
|
* trail not trusted.
|
|
*/
|
|
if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_verify(ep, NULL, peer)) !=
|
|
XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* Pass the extension field to the transmit
|
|
* side. If already agreed, walk away.
|
|
*/
|
|
fp = emalloc(len);
|
|
memcpy(fp, ep, len);
|
|
temp32 = CRYPTO_RESP;
|
|
fp->opcode |= htonl(temp32);
|
|
peer->cmmd = fp;
|
|
if (peer->crypto & CRYPTO_FLAG_AGREE) {
|
|
peer->flash &= ~TEST8;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Install cookie values and light the cookie
|
|
* bit. The transmit side will pick up and
|
|
* encrypt it for the response.
|
|
*/
|
|
key_expire(peer);
|
|
peer->cookval.tstamp = ep->tstamp;
|
|
peer->cookval.fstamp = ep->fstamp;
|
|
RAND_bytes((u_char *)&peer->pcookie, 4);
|
|
peer->crypto &= ~CRYPTO_FLAG_AUTO;
|
|
peer->crypto |= CRYPTO_FLAG_AGREE;
|
|
peer->flash &= ~TEST8;
|
|
snprintf(statstr, NTP_MAXSTRLEN, "cook %x ts %u fs %u",
|
|
peer->pcookie, ntohl(ep->tstamp),
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* Cookie response in client and symmetric modes. If the
|
|
* cookie bit is set, the working cookie is the EXOR of
|
|
* the current and new values.
|
|
*/
|
|
case CRYPTO_COOK | CRYPTO_RESP:
|
|
|
|
/*
|
|
* Discard the message if invalid or identity
|
|
* not confirmed or signature not verified with
|
|
* respect to the cookie values.
|
|
*/
|
|
if (!(peer->crypto & CRYPTO_FLAG_VRFY)) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_verify(ep, &peer->cookval,
|
|
peer)) != XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* Decrypt the cookie, hunting all the time for
|
|
* errors.
|
|
*/
|
|
if (vallen == (u_int) EVP_PKEY_size(host_pkey)) {
|
|
RSA_private_decrypt(vallen,
|
|
(u_char *)ep->pkt,
|
|
(u_char *)&temp32,
|
|
host_pkey->pkey.rsa,
|
|
RSA_PKCS1_OAEP_PADDING);
|
|
cookie = ntohl(temp32);
|
|
} else {
|
|
rval = XEVNT_CKY;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Install cookie values and light the cookie
|
|
* bit. If this is not broadcast client mode, we
|
|
* are done here.
|
|
*/
|
|
key_expire(peer);
|
|
peer->cookval.tstamp = ep->tstamp;
|
|
peer->cookval.fstamp = ep->fstamp;
|
|
if (peer->crypto & CRYPTO_FLAG_AGREE)
|
|
peer->pcookie ^= cookie;
|
|
else
|
|
peer->pcookie = cookie;
|
|
if (peer->hmode == MODE_CLIENT &&
|
|
!(peer->cast_flags & MDF_BCLNT))
|
|
peer->crypto |= CRYPTO_FLAG_AUTO;
|
|
else
|
|
peer->crypto &= ~CRYPTO_FLAG_AUTO;
|
|
peer->crypto |= CRYPTO_FLAG_AGREE;
|
|
peer->flash &= ~TEST8;
|
|
snprintf(statstr, NTP_MAXSTRLEN, "cook %x ts %u fs %u",
|
|
peer->pcookie, ntohl(ep->tstamp),
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* Install autokey values in broadcast client and
|
|
* symmetric modes. We have to do this every time the
|
|
* sever/peer cookie changes or a new keylist is
|
|
* rolled. Ordinarily, this is automatic as this message
|
|
* is piggybacked on the first NTP packet sent upon
|
|
* either of these events. Note that a broadcast client
|
|
* or symmetric peer can receive this response without a
|
|
* matching request.
|
|
*/
|
|
case CRYPTO_AUTO | CRYPTO_RESP:
|
|
|
|
/*
|
|
* Discard the message if invalid or identity
|
|
* not confirmed or signature not verified with
|
|
* respect to the receive autokey values.
|
|
*/
|
|
if (!(peer->crypto & CRYPTO_FLAG_VRFY)) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_verify(ep, &peer->recval,
|
|
peer)) != XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* Install autokey values and light the
|
|
* autokey bit. This is not hard.
|
|
*/
|
|
if (peer->recval.ptr == NULL)
|
|
peer->recval.ptr =
|
|
emalloc(sizeof(struct autokey));
|
|
bp = (struct autokey *)peer->recval.ptr;
|
|
peer->recval.tstamp = ep->tstamp;
|
|
peer->recval.fstamp = ep->fstamp;
|
|
ap = (struct autokey *)ep->pkt;
|
|
bp->seq = ntohl(ap->seq);
|
|
bp->key = ntohl(ap->key);
|
|
peer->pkeyid = bp->key;
|
|
peer->crypto |= CRYPTO_FLAG_AUTO;
|
|
peer->flash &= ~TEST8;
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"auto seq %d key %x ts %u fs %u", bp->seq,
|
|
bp->key, ntohl(ep->tstamp),
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* X509 certificate sign response. Validate the
|
|
* certificate signed by the server and install. Later
|
|
* this can be provided to clients of this server in
|
|
* lieu of the self signed certificate in order to
|
|
* validate the public key.
|
|
*/
|
|
case CRYPTO_SIGN | CRYPTO_RESP:
|
|
|
|
/*
|
|
* Discard the message if invalid or not
|
|
* proventic.
|
|
*/
|
|
if (!(peer->crypto & CRYPTO_FLAG_PROV)) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_verify(ep, NULL, peer)) !=
|
|
XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* Scan the certificate list to delete old
|
|
* versions and link the newest version first on
|
|
* the list.
|
|
*/
|
|
if ((rval = cert_install(ep, peer)) != XEVNT_OK)
|
|
break;
|
|
|
|
peer->crypto |= CRYPTO_FLAG_SIGN;
|
|
peer->flash &= ~TEST8;
|
|
temp32 = cinfo->nid;
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"sign %s 0x%x %s (%u) fs %u",
|
|
cinfo->issuer, cinfo->flags,
|
|
OBJ_nid2ln(temp32), temp32,
|
|
ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* Install leapseconds table in symmetric modes. This
|
|
* table is proventicated to the NIST primary servers,
|
|
* either by copying the file containing the table from
|
|
* a NIST server to a trusted server or directly using
|
|
* this protocol. While the entire table is installed at
|
|
* the server, presently only the current TAI offset is
|
|
* provided via the kernel to other applications.
|
|
*/
|
|
case CRYPTO_TAI:
|
|
|
|
/*
|
|
* Discard the message if invalid.
|
|
*/
|
|
if ((rval = crypto_verify(ep, NULL, peer)) !=
|
|
XEVNT_OK)
|
|
break;
|
|
|
|
/*
|
|
* Pass the extension field to the transmit
|
|
* side. Continue below if a leapseconds table
|
|
* accompanies the message.
|
|
*/
|
|
fp = emalloc(len);
|
|
memcpy(fp, ep, len);
|
|
temp32 = CRYPTO_RESP;
|
|
fp->opcode |= htonl(temp32);
|
|
peer->cmmd = fp;
|
|
if (len <= VALUE_LEN) {
|
|
peer->flash &= ~TEST8;
|
|
break;
|
|
}
|
|
/* fall through */
|
|
|
|
case CRYPTO_TAI | CRYPTO_RESP:
|
|
|
|
/*
|
|
* If this is a response, discard the message if
|
|
* signature not verified with respect to the
|
|
* leapsecond table values.
|
|
*/
|
|
if (peer->cmmd == NULL) {
|
|
if ((rval = crypto_verify(ep,
|
|
&peer->tai_leap, peer)) != XEVNT_OK)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Initialize peer variables with latest update.
|
|
*/
|
|
peer->tai_leap.tstamp = ep->tstamp;
|
|
peer->tai_leap.fstamp = ep->fstamp;
|
|
peer->tai_leap.vallen = ep->vallen;
|
|
|
|
/*
|
|
* Install the new table if there is no stored
|
|
* table or the new table is more recent than
|
|
* the stored table. Since a filestamp may have
|
|
* changed, recompute the signatures.
|
|
*/
|
|
if (ntohl(peer->tai_leap.fstamp) >
|
|
ntohl(tai_leap.fstamp)) {
|
|
tai_leap.fstamp = ep->fstamp;
|
|
tai_leap.vallen = ep->vallen;
|
|
if (tai_leap.ptr != NULL)
|
|
free(tai_leap.ptr);
|
|
tai_leap.ptr = emalloc(vallen);
|
|
memcpy(tai_leap.ptr, ep->pkt, vallen);
|
|
crypto_update();
|
|
}
|
|
crypto_flags |= CRYPTO_FLAG_TAI;
|
|
peer->crypto |= CRYPTO_FLAG_LEAP;
|
|
peer->flash &= ~TEST8;
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"leap %u ts %u fs %u", vallen,
|
|
ntohl(ep->tstamp), ntohl(ep->fstamp));
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* We come here in symmetric modes for miscellaneous
|
|
* commands that have value fields but are processed on
|
|
* the transmit side. All we need do here is check for
|
|
* valid field length. Remaining checks are below and on
|
|
* the transmit side.
|
|
*/
|
|
case CRYPTO_CERT:
|
|
case CRYPTO_IFF:
|
|
case CRYPTO_GQ:
|
|
case CRYPTO_MV:
|
|
case CRYPTO_SIGN:
|
|
if (len < VALUE_LEN) {
|
|
rval = XEVNT_LEN;
|
|
break;
|
|
}
|
|
/* fall through */
|
|
|
|
/*
|
|
* We come here for miscellaneous requests and unknown
|
|
* requests and responses. If an unknown response or
|
|
* error, forget it. If a request, save the extension
|
|
* field for later. Unknown requests will be caught on
|
|
* the transmit side.
|
|
*/
|
|
default:
|
|
if (code & (CRYPTO_RESP | CRYPTO_ERROR)) {
|
|
rval = XEVNT_ERR;
|
|
} else if ((rval = crypto_verify(ep, NULL,
|
|
peer)) == XEVNT_OK) {
|
|
fp = emalloc(len);
|
|
memcpy(fp, ep, len);
|
|
temp32 = CRYPTO_RESP;
|
|
fp->opcode |= htonl(temp32);
|
|
peer->cmmd = fp;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We don't log length/format/timestamp errors and
|
|
* duplicates, which are log clogging vulnerabilities.
|
|
* The first error found terminates the extension field
|
|
* scan and we return the laundry to the caller. A
|
|
* length/format/timestamp error on transmit is
|
|
* cheerfully ignored, as the message is not sent.
|
|
*/
|
|
if (rval > XEVNT_TSP) {
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"error %x opcode %x ts %u fs %u", rval,
|
|
code, tstamp, fstamp);
|
|
record_crypto_stats(&peer->srcadr, statstr);
|
|
report_event(rval, peer);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_recv: %s\n", statstr);
|
|
#endif
|
|
break;
|
|
|
|
} else if (rval > XEVNT_OK && (code & CRYPTO_RESP)) {
|
|
rval = XEVNT_OK;
|
|
}
|
|
authlen += len;
|
|
}
|
|
return (rval);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_xmit - construct extension fields
|
|
*
|
|
* This routine is called both when an association is configured and
|
|
* when one is not. The only case where this matters is to retrieve the
|
|
* autokey information, in which case the caller has to provide the
|
|
* association ID to match the association.
|
|
*
|
|
* Returns length of extension field.
|
|
*/
|
|
int
|
|
crypto_xmit(
|
|
struct pkt *xpkt, /* transmit packet pointer */
|
|
struct sockaddr_storage *srcadr_sin, /* active runway */
|
|
int start, /* offset to extension field */
|
|
struct exten *ep, /* extension pointer */
|
|
keyid_t cookie /* session cookie */
|
|
)
|
|
{
|
|
u_int32 *pkt; /* packet pointer */
|
|
struct peer *peer; /* peer structure pointer */
|
|
u_int opcode; /* extension field opcode */
|
|
struct exten *fp; /* extension pointers */
|
|
struct cert_info *cp, *xp; /* certificate info/value pointer */
|
|
char certname[MAXHOSTNAME + 1]; /* subject name buffer */
|
|
char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
|
|
tstamp_t tstamp;
|
|
u_int vallen;
|
|
u_int len;
|
|
struct value vtemp;
|
|
associd_t associd;
|
|
int rval;
|
|
keyid_t tcookie;
|
|
|
|
/*
|
|
* Generate the requested extension field request code, length
|
|
* and association ID. If this is a response and the host is not
|
|
* synchronized, light the error bit and go home.
|
|
*/
|
|
pkt = (u_int32 *)xpkt + start / 4;
|
|
fp = (struct exten *)pkt;
|
|
opcode = ntohl(ep->opcode);
|
|
associd = (associd_t) ntohl(ep->associd);
|
|
fp->associd = htonl(associd);
|
|
len = 8;
|
|
rval = XEVNT_OK;
|
|
tstamp = crypto_time();
|
|
switch (opcode & 0xffff0000) {
|
|
|
|
/*
|
|
* Send association request and response with status word and
|
|
* host name. Note, this message is not signed and the filestamp
|
|
* contains only the status word.
|
|
*/
|
|
case CRYPTO_ASSOC | CRYPTO_RESP:
|
|
len += crypto_send(fp, &hostval);
|
|
fp->fstamp = htonl(crypto_flags);
|
|
break;
|
|
|
|
case CRYPTO_ASSOC:
|
|
len += crypto_send(fp, &hostval);
|
|
fp->fstamp = htonl(crypto_flags | ident_scheme);
|
|
break;
|
|
|
|
/*
|
|
* Send certificate request. Use the values from the extension
|
|
* field.
|
|
*/
|
|
case CRYPTO_CERT:
|
|
memset(&vtemp, 0, sizeof(vtemp));
|
|
vtemp.tstamp = ep->tstamp;
|
|
vtemp.fstamp = ep->fstamp;
|
|
vtemp.vallen = ep->vallen;
|
|
vtemp.ptr = (u_char *)ep->pkt;
|
|
len += crypto_send(fp, &vtemp);
|
|
break;
|
|
|
|
/*
|
|
* Send certificate response or sign request. Use the values
|
|
* from the certificate cache. If the request contains no
|
|
* subject name, assume the name of this host. This is for
|
|
* backwards compatibility. Private certificates are never sent.
|
|
*/
|
|
case CRYPTO_SIGN:
|
|
case CRYPTO_CERT | CRYPTO_RESP:
|
|
vallen = ntohl(ep->vallen);
|
|
if (vallen == 8) {
|
|
strcpy(certname, sys_hostname);
|
|
} else if (vallen == 0 || vallen > MAXHOSTNAME) {
|
|
rval = XEVNT_LEN;
|
|
break;
|
|
|
|
} else {
|
|
memcpy(certname, ep->pkt, vallen);
|
|
certname[vallen] = '\0';
|
|
}
|
|
|
|
/*
|
|
* Find all certificates with matching subject. If a
|
|
* self-signed, trusted certificate is found, use that.
|
|
* If not, use the first one with matching subject. A
|
|
* private certificate is never divulged or signed.
|
|
*/
|
|
xp = NULL;
|
|
for (cp = cinfo; cp != NULL; cp = cp->link) {
|
|
if (cp->flags & CERT_PRIV)
|
|
continue;
|
|
|
|
if (strcmp(certname, cp->subject) == 0) {
|
|
if (xp == NULL)
|
|
xp = cp;
|
|
if (strcmp(certname, cp->issuer) ==
|
|
0 && cp->flags & CERT_TRUST) {
|
|
xp = cp;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Be careful who you trust. If not yet synchronized,
|
|
* give back an empty response. If certificate not found
|
|
* or beyond the lifetime, return an error. This is to
|
|
* avoid a bad dude trying to get an expired certificate
|
|
* re-signed. Otherwise, send it.
|
|
*
|
|
* Note the timestamp and filestamp are taken from the
|
|
* certificate value structure. For all certificates the
|
|
* timestamp is the latest signature update time. For
|
|
* host and imported certificates the filestamp is the
|
|
* creation epoch. For signed certificates the filestamp
|
|
* is the creation epoch of the trusted certificate at
|
|
* the base of the certificate trail. In principle, this
|
|
* allows strong checking for signature masquerade.
|
|
*/
|
|
if (tstamp == 0)
|
|
break;
|
|
|
|
if (xp == NULL)
|
|
rval = XEVNT_CRT;
|
|
else if (tstamp < xp->first || tstamp > xp->last)
|
|
rval = XEVNT_SRV;
|
|
else
|
|
len += crypto_send(fp, &xp->cert);
|
|
break;
|
|
|
|
/*
|
|
* Send challenge in Schnorr (IFF) identity scheme.
|
|
*/
|
|
case CRYPTO_IFF:
|
|
if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_alice(peer, &vtemp)) == XEVNT_OK) {
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Send response in Schnorr (IFF) identity scheme.
|
|
*/
|
|
case CRYPTO_IFF | CRYPTO_RESP:
|
|
if ((rval = crypto_bob(ep, &vtemp)) == XEVNT_OK) {
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Send challenge in Guillou-Quisquater (GQ) identity scheme.
|
|
*/
|
|
case CRYPTO_GQ:
|
|
if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_alice2(peer, &vtemp)) == XEVNT_OK) {
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Send response in Guillou-Quisquater (GQ) identity scheme.
|
|
*/
|
|
case CRYPTO_GQ | CRYPTO_RESP:
|
|
if ((rval = crypto_bob2(ep, &vtemp)) == XEVNT_OK) {
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Send challenge in MV identity scheme.
|
|
*/
|
|
case CRYPTO_MV:
|
|
if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
if ((rval = crypto_alice3(peer, &vtemp)) == XEVNT_OK) {
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Send response in MV identity scheme.
|
|
*/
|
|
case CRYPTO_MV | CRYPTO_RESP:
|
|
if ((rval = crypto_bob3(ep, &vtemp)) == XEVNT_OK) {
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Send certificate sign response. The integrity of the request
|
|
* certificate has already been verified on the receive side.
|
|
* Sign the response using the local server key. Use the
|
|
* filestamp from the request and use the timestamp as the
|
|
* current time. Light the error bit if the certificate is
|
|
* invalid or contains an unverified signature.
|
|
*/
|
|
case CRYPTO_SIGN | CRYPTO_RESP:
|
|
if ((rval = cert_sign(ep, &vtemp)) == XEVNT_OK)
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
break;
|
|
|
|
/*
|
|
* Send public key and signature. Use the values from the public
|
|
* key.
|
|
*/
|
|
case CRYPTO_COOK:
|
|
len += crypto_send(fp, &pubkey);
|
|
break;
|
|
|
|
/*
|
|
* Encrypt and send cookie and signature. Light the error bit if
|
|
* anything goes wrong.
|
|
*/
|
|
case CRYPTO_COOK | CRYPTO_RESP:
|
|
if ((opcode & 0xffff) < VALUE_LEN) {
|
|
rval = XEVNT_LEN;
|
|
break;
|
|
}
|
|
if (PKT_MODE(xpkt->li_vn_mode) == MODE_SERVER) {
|
|
tcookie = cookie;
|
|
} else {
|
|
if ((peer = findpeerbyassoc(associd)) == NULL) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
tcookie = peer->pcookie;
|
|
}
|
|
if ((rval = crypto_encrypt(ep, &vtemp, &tcookie)) ==
|
|
XEVNT_OK)
|
|
len += crypto_send(fp, &vtemp);
|
|
value_free(&vtemp);
|
|
break;
|
|
|
|
/*
|
|
* Find peer and send autokey data and signature in broadcast
|
|
* server and symmetric modes. Use the values in the autokey
|
|
* structure. If no association is found, either the server has
|
|
* restarted with new associations or some perp has replayed an
|
|
* old message, in which case light the error bit.
|
|
*/
|
|
case CRYPTO_AUTO | CRYPTO_RESP:
|
|
if ((peer = findpeerbyassoc(associd)) == NULL) {
|
|
rval = XEVNT_ERR;
|
|
break;
|
|
}
|
|
peer->flags &= ~FLAG_ASSOC;
|
|
len += crypto_send(fp, &peer->sndval);
|
|
break;
|
|
|
|
/*
|
|
* Send leapseconds table and signature. Use the values from the
|
|
* tai structure. If no table has been loaded, just send an
|
|
* empty request.
|
|
*/
|
|
case CRYPTO_TAI:
|
|
case CRYPTO_TAI | CRYPTO_RESP:
|
|
if (crypto_flags & CRYPTO_FLAG_TAI)
|
|
len += crypto_send(fp, &tai_leap);
|
|
break;
|
|
|
|
/*
|
|
* Default - Fall through for requests; for unknown responses,
|
|
* flag as error.
|
|
*/
|
|
default:
|
|
if (opcode & CRYPTO_RESP)
|
|
rval = XEVNT_ERR;
|
|
}
|
|
|
|
/*
|
|
* In case of error, flame the log. If a request, toss the
|
|
* puppy; if a response, return so the sender can flame, too.
|
|
*/
|
|
if (rval != XEVNT_OK) {
|
|
opcode |= CRYPTO_ERROR;
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"error %x opcode %x", rval, opcode);
|
|
record_crypto_stats(srcadr_sin, statstr);
|
|
report_event(rval, NULL);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_xmit: %s\n", statstr);
|
|
#endif
|
|
if (!(opcode & CRYPTO_RESP))
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Round up the field length to a multiple of 8 bytes and save
|
|
* the request code and length.
|
|
*/
|
|
len = ((len + 7) / 8) * 8;
|
|
fp->opcode = htonl((opcode & 0xffff0000) | len);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf(
|
|
"crypto_xmit: flags 0x%x ext offset %d len %u code 0x%x assocID %d\n",
|
|
crypto_flags, start, len, opcode >> 16, associd);
|
|
#endif
|
|
return (len);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_verify - parse and verify the extension field and value
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_LEN bad field format or length
|
|
* XEVNT_TSP bad timestamp
|
|
* XEVNT_FSP bad filestamp
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_SGL bad signature length
|
|
* XEVNT_SIG signature not verified
|
|
* XEVNT_ERR protocol error
|
|
*/
|
|
static int
|
|
crypto_verify(
|
|
struct exten *ep, /* extension pointer */
|
|
struct value *vp, /* value pointer */
|
|
struct peer *peer /* peer structure pointer */
|
|
)
|
|
{
|
|
EVP_PKEY *pkey; /* server public key */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp, tstamp1 = 0; /* timestamp */
|
|
tstamp_t fstamp, fstamp1 = 0; /* filestamp */
|
|
u_int vallen; /* value length */
|
|
u_int siglen; /* signature length */
|
|
u_int opcode, len;
|
|
int i;
|
|
|
|
/*
|
|
* We require valid opcode and field lengths, timestamp,
|
|
* filestamp, public key, digest, signature length and
|
|
* signature, where relevant. Note that preliminary length
|
|
* checks are done in the main loop.
|
|
*/
|
|
len = ntohl(ep->opcode) & 0x0000ffff;
|
|
opcode = ntohl(ep->opcode) & 0xffff0000;
|
|
|
|
/*
|
|
* Check for valid operation code and protocol. The opcode must
|
|
* not have the error bit set. If a response, it must have a
|
|
* value header. If a request and does not contain a value
|
|
* header, no need for further checking.
|
|
*/
|
|
if (opcode & CRYPTO_ERROR)
|
|
return (XEVNT_ERR);
|
|
|
|
if (opcode & CRYPTO_RESP) {
|
|
if (len < VALUE_LEN)
|
|
return (XEVNT_LEN);
|
|
} else {
|
|
if (len < VALUE_LEN)
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
/*
|
|
* We have a value header. Check for valid field lengths. The
|
|
* field length must be long enough to contain the value header,
|
|
* value and signature. Note both the value and signature fields
|
|
* are rounded up to the next word.
|
|
*/
|
|
vallen = ntohl(ep->vallen);
|
|
i = (vallen + 3) / 4;
|
|
siglen = ntohl(ep->pkt[i++]);
|
|
if (len < VALUE_LEN + ((vallen + 3) / 4) * 4 + ((siglen + 3) /
|
|
4) * 4)
|
|
return (XEVNT_LEN);
|
|
|
|
/*
|
|
* Punt if this is a response with no data. Punt if this is a
|
|
* request and a previous response is pending.
|
|
*/
|
|
if (opcode & CRYPTO_RESP) {
|
|
if (vallen == 0)
|
|
return (XEVNT_LEN);
|
|
} else {
|
|
if (peer->cmmd != NULL)
|
|
return (XEVNT_LEN);
|
|
}
|
|
|
|
/*
|
|
* Check for valid timestamp and filestamp. If the timestamp is
|
|
* zero, the sender is not synchronized and signatures are
|
|
* disregarded. If not, the timestamp must not precede the
|
|
* filestamp. The timestamp and filestamp must not precede the
|
|
* corresponding values in the value structure, if present. Once
|
|
* the autokey values have been installed, the timestamp must
|
|
* always be later than the corresponding value in the value
|
|
* structure. Duplicate timestamps are illegal once the cookie
|
|
* has been validated.
|
|
*/
|
|
tstamp = ntohl(ep->tstamp);
|
|
fstamp = ntohl(ep->fstamp);
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < fstamp)
|
|
return (XEVNT_TSP);
|
|
|
|
if (vp != NULL) {
|
|
tstamp1 = ntohl(vp->tstamp);
|
|
fstamp1 = ntohl(vp->fstamp);
|
|
if ((tstamp < tstamp1 || (tstamp == tstamp1 &&
|
|
(peer->crypto & CRYPTO_FLAG_AUTO))))
|
|
return (XEVNT_TSP);
|
|
|
|
if ((tstamp < fstamp1 || fstamp < fstamp1))
|
|
return (XEVNT_FSP);
|
|
}
|
|
|
|
/*
|
|
* Check for valid signature length, public key and digest
|
|
* algorithm.
|
|
*/
|
|
if (crypto_flags & peer->crypto & CRYPTO_FLAG_PRIV)
|
|
pkey = sign_pkey;
|
|
else
|
|
pkey = peer->pkey;
|
|
if (siglen == 0 || pkey == NULL || peer->digest == NULL)
|
|
return (XEVNT_OK);
|
|
|
|
if (siglen != (u_int)EVP_PKEY_size(pkey))
|
|
return (XEVNT_SGL);
|
|
|
|
/*
|
|
* Darn, I thought we would never get here. Verify the
|
|
* signature. If the identity exchange is verified, light the
|
|
* proventic bit. If no client identity scheme is specified,
|
|
* avoid doing the sign exchange.
|
|
*/
|
|
EVP_VerifyInit(&ctx, peer->digest);
|
|
EVP_VerifyUpdate(&ctx, (u_char *)&ep->tstamp, vallen + 12);
|
|
if (EVP_VerifyFinal(&ctx, (u_char *)&ep->pkt[i], siglen, pkey) <= 0)
|
|
return (XEVNT_SIG);
|
|
|
|
if (peer->crypto & CRYPTO_FLAG_VRFY) {
|
|
peer->crypto |= CRYPTO_FLAG_PROV;
|
|
if (!(crypto_flags & CRYPTO_FLAG_MASK))
|
|
peer->crypto |= CRYPTO_FLAG_SIGN;
|
|
}
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_encrypt - construct encrypted cookie and signature from
|
|
* extension field and cookie
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_CKY bad or missing cookie
|
|
* XEVNT_PER host certificate expired
|
|
*/
|
|
static int
|
|
crypto_encrypt(
|
|
struct exten *ep, /* extension pointer */
|
|
struct value *vp, /* value pointer */
|
|
keyid_t *cookie /* server cookie */
|
|
)
|
|
{
|
|
EVP_PKEY *pkey; /* public key */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp; /* NTP timestamp */
|
|
u_int32 temp32;
|
|
u_int len;
|
|
u_char *ptr;
|
|
|
|
/*
|
|
* Extract the public key from the request.
|
|
*/
|
|
len = ntohl(ep->vallen);
|
|
ptr = (u_char *)ep->pkt;
|
|
pkey = d2i_PublicKey(EVP_PKEY_RSA, NULL, &ptr, len);
|
|
if (pkey == NULL) {
|
|
msyslog(LOG_ERR, "crypto_encrypt %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_PUB);
|
|
}
|
|
|
|
/*
|
|
* Encrypt the cookie, encode in ASN.1 and sign.
|
|
*/
|
|
tstamp = crypto_time();
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = hostval.tstamp;
|
|
len = EVP_PKEY_size(pkey);
|
|
vp->vallen = htonl(len);
|
|
vp->ptr = emalloc(len);
|
|
temp32 = htonl(*cookie);
|
|
if (!RSA_public_encrypt(4, (u_char *)&temp32, vp->ptr,
|
|
pkey->pkey.rsa, RSA_PKCS1_OAEP_PADDING)) {
|
|
msyslog(LOG_ERR, "crypto_encrypt %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
EVP_PKEY_free(pkey);
|
|
return (XEVNT_CKY);
|
|
}
|
|
EVP_PKEY_free(pkey);
|
|
vp->siglen = 0;
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_ident - construct extension field for identity scheme
|
|
*
|
|
* This routine determines which identity scheme is in use and
|
|
* constructs an extension field for that scheme.
|
|
*/
|
|
u_int
|
|
crypto_ident(
|
|
struct peer *peer /* peer structure pointer */
|
|
)
|
|
{
|
|
char filename[MAXFILENAME + 1];
|
|
|
|
/*
|
|
* If the server identity has already been verified, no further
|
|
* action is necessary. Otherwise, try to load the identity file
|
|
* of the certificate issuer. If the issuer file is not found,
|
|
* try the host file. If nothing found, declare a cryptobust.
|
|
* Note we can't get here unless the trusted certificate has
|
|
* been found and the CRYPTO_FLAG_VALID bit is set, so the
|
|
* certificate issuer is valid.
|
|
*/
|
|
if (peer->ident_pkey != NULL)
|
|
EVP_PKEY_free(peer->ident_pkey);
|
|
if (peer->crypto & CRYPTO_FLAG_GQ) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
|
|
peer->issuer);
|
|
peer->ident_pkey = crypto_key(filename, &peer->fstamp);
|
|
if (peer->ident_pkey != NULL)
|
|
return (CRYPTO_GQ);
|
|
|
|
snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
|
|
sys_hostname);
|
|
peer->ident_pkey = crypto_key(filename, &peer->fstamp);
|
|
if (peer->ident_pkey != NULL)
|
|
return (CRYPTO_GQ);
|
|
}
|
|
if (peer->crypto & CRYPTO_FLAG_IFF) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
|
|
peer->issuer);
|
|
peer->ident_pkey = crypto_key(filename, &peer->fstamp);
|
|
if (peer->ident_pkey != NULL)
|
|
return (CRYPTO_IFF);
|
|
|
|
snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
|
|
sys_hostname);
|
|
peer->ident_pkey = crypto_key(filename, &peer->fstamp);
|
|
if (peer->ident_pkey != NULL)
|
|
return (CRYPTO_IFF);
|
|
}
|
|
if (peer->crypto & CRYPTO_FLAG_MV) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
|
|
peer->issuer);
|
|
peer->ident_pkey = crypto_key(filename, &peer->fstamp);
|
|
if (peer->ident_pkey != NULL)
|
|
return (CRYPTO_MV);
|
|
|
|
snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
|
|
sys_hostname);
|
|
peer->ident_pkey = crypto_key(filename, &peer->fstamp);
|
|
if (peer->ident_pkey != NULL)
|
|
return (CRYPTO_MV);
|
|
}
|
|
|
|
/*
|
|
* No compatible identity scheme is available. Life is hard.
|
|
*/
|
|
msyslog(LOG_INFO,
|
|
"crypto_ident: no compatible identity scheme found");
|
|
return (0);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_args - construct extension field from arguments
|
|
*
|
|
* This routine creates an extension field with current timestamps and
|
|
* specified opcode, association ID and optional string. Note that the
|
|
* extension field is created here, but freed after the crypto_xmit()
|
|
* call in the protocol module.
|
|
*
|
|
* Returns extension field pointer (no errors).
|
|
*/
|
|
struct exten *
|
|
crypto_args(
|
|
struct peer *peer, /* peer structure pointer */
|
|
u_int opcode, /* operation code */
|
|
char *str /* argument string */
|
|
)
|
|
{
|
|
tstamp_t tstamp; /* NTP timestamp */
|
|
struct exten *ep; /* extension field pointer */
|
|
u_int len; /* extension field length */
|
|
|
|
tstamp = crypto_time();
|
|
len = sizeof(struct exten);
|
|
if (str != NULL)
|
|
len += strlen(str);
|
|
ep = emalloc(len);
|
|
memset(ep, 0, len);
|
|
if (opcode == 0)
|
|
return (ep);
|
|
|
|
ep->opcode = htonl(opcode + len);
|
|
|
|
/*
|
|
* If a response, send our ID; if a request, send the
|
|
* responder's ID.
|
|
*/
|
|
if (opcode & CRYPTO_RESP)
|
|
ep->associd = htonl(peer->associd);
|
|
else
|
|
ep->associd = htonl(peer->assoc);
|
|
ep->tstamp = htonl(tstamp);
|
|
ep->fstamp = hostval.tstamp;
|
|
ep->vallen = 0;
|
|
if (str != NULL) {
|
|
ep->vallen = htonl(strlen(str));
|
|
memcpy((char *)ep->pkt, str, strlen(str));
|
|
} else {
|
|
ep->pkt[0] = peer->associd;
|
|
}
|
|
return (ep);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_send - construct extension field from value components
|
|
*
|
|
* Returns extension field length. Note: it is not polite to send a
|
|
* nonempty signature with zero timestamp or a nonzero timestamp with
|
|
* empty signature, but these rules are not enforced here.
|
|
*/
|
|
u_int
|
|
crypto_send(
|
|
struct exten *ep, /* extension field pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
u_int len, temp32;
|
|
int i;
|
|
|
|
/*
|
|
* Copy data. If the data field is empty or zero length, encode
|
|
* an empty value with length zero.
|
|
*/
|
|
ep->tstamp = vp->tstamp;
|
|
ep->fstamp = vp->fstamp;
|
|
ep->vallen = vp->vallen;
|
|
len = 12;
|
|
temp32 = ntohl(vp->vallen);
|
|
if (temp32 > 0 && vp->ptr != NULL)
|
|
memcpy(ep->pkt, vp->ptr, temp32);
|
|
|
|
/*
|
|
* Copy signature. If the signature field is empty or zero
|
|
* length, encode an empty signature with length zero.
|
|
*/
|
|
i = (temp32 + 3) / 4;
|
|
len += i * 4 + 4;
|
|
ep->pkt[i++] = vp->siglen;
|
|
temp32 = ntohl(vp->siglen);
|
|
if (temp32 > 0 && vp->sig != NULL)
|
|
memcpy(&ep->pkt[i], vp->sig, temp32);
|
|
len += temp32;
|
|
return (len);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_update - compute new public value and sign extension fields
|
|
*
|
|
* This routine runs periodically, like once a day, and when something
|
|
* changes. It updates the timestamps on three value structures and one
|
|
* value structure list, then signs all the structures:
|
|
*
|
|
* hostval host name (not signed)
|
|
* pubkey public key
|
|
* cinfo certificate info/value list
|
|
* tai_leap leapseconds file
|
|
*
|
|
* Filestamps are proventicated data, so this routine is run only when
|
|
* the host has been synchronized to a proventicated source. Thus, the
|
|
* timestamp is proventicated, too, and can be used to deflect
|
|
* clogging attacks and even cook breakfast.
|
|
*
|
|
* Returns void (no errors)
|
|
*/
|
|
void
|
|
crypto_update(void)
|
|
{
|
|
EVP_MD_CTX ctx; /* message digest context */
|
|
struct cert_info *cp, *cpn; /* certificate info/value */
|
|
char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
|
|
tstamp_t tstamp; /* NTP timestamp */
|
|
u_int len;
|
|
|
|
if ((tstamp = crypto_time()) == 0)
|
|
return;
|
|
|
|
hostval.tstamp = htonl(tstamp);
|
|
|
|
/*
|
|
* Sign public key and timestamps. The filestamp is derived from
|
|
* the host key file extension from wherever the file was
|
|
* generated.
|
|
*/
|
|
if (pubkey.vallen != 0) {
|
|
pubkey.tstamp = hostval.tstamp;
|
|
pubkey.siglen = 0;
|
|
if (pubkey.sig == NULL)
|
|
pubkey.sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&pubkey, 12);
|
|
EVP_SignUpdate(&ctx, pubkey.ptr, ntohl(pubkey.vallen));
|
|
if (EVP_SignFinal(&ctx, pubkey.sig, &len, sign_pkey))
|
|
pubkey.siglen = htonl(len);
|
|
}
|
|
|
|
/*
|
|
* Sign certificates and timestamps. The filestamp is derived
|
|
* from the certificate file extension from wherever the file
|
|
* was generated. Note we do not throw expired certificates
|
|
* away; they may have signed younger ones.
|
|
*/
|
|
for (cp = cinfo; cp != NULL; cp = cpn) {
|
|
cpn = cp->link;
|
|
cp->cert.tstamp = hostval.tstamp;
|
|
cp->cert.siglen = 0;
|
|
if (cp->cert.sig == NULL)
|
|
cp->cert.sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&cp->cert, 12);
|
|
EVP_SignUpdate(&ctx, cp->cert.ptr,
|
|
ntohl(cp->cert.vallen));
|
|
if (EVP_SignFinal(&ctx, cp->cert.sig, &len, sign_pkey))
|
|
cp->cert.siglen = htonl(len);
|
|
}
|
|
|
|
/*
|
|
* Sign leapseconds table and timestamps. The filestamp is
|
|
* derived from the leapsecond file extension from wherever the
|
|
* file was generated.
|
|
*/
|
|
if (tai_leap.vallen != 0) {
|
|
tai_leap.tstamp = hostval.tstamp;
|
|
tai_leap.siglen = 0;
|
|
if (tai_leap.sig == NULL)
|
|
tai_leap.sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&tai_leap, 12);
|
|
EVP_SignUpdate(&ctx, tai_leap.ptr,
|
|
ntohl(tai_leap.vallen));
|
|
if (EVP_SignFinal(&ctx, tai_leap.sig, &len, sign_pkey))
|
|
tai_leap.siglen = htonl(len);
|
|
}
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"update ts %u", ntohl(hostval.tstamp));
|
|
record_crypto_stats(NULL, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_update: %s\n", statstr);
|
|
#endif
|
|
}
|
|
|
|
|
|
/*
|
|
* value_free - free value structure components.
|
|
*
|
|
* Returns void (no errors)
|
|
*/
|
|
void
|
|
value_free(
|
|
struct value *vp /* value structure */
|
|
)
|
|
{
|
|
if (vp->ptr != NULL)
|
|
free(vp->ptr);
|
|
if (vp->sig != NULL)
|
|
free(vp->sig);
|
|
memset(vp, 0, sizeof(struct value));
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_time - returns current NTP time in seconds.
|
|
*/
|
|
tstamp_t
|
|
crypto_time()
|
|
{
|
|
l_fp tstamp; /* NTP time */ L_CLR(&tstamp);
|
|
|
|
L_CLR(&tstamp);
|
|
if (sys_leap != LEAP_NOTINSYNC)
|
|
get_systime(&tstamp);
|
|
return (tstamp.l_ui);
|
|
}
|
|
|
|
|
|
/*
|
|
* asn2ntp - convert ASN1_TIME time structure to NTP time in seconds.
|
|
*/
|
|
u_long
|
|
asn2ntp (
|
|
ASN1_TIME *asn1time /* pointer to ASN1_TIME structure */
|
|
)
|
|
{
|
|
char *v; /* pointer to ASN1_TIME string */
|
|
struct tm tm; /* used to convert to NTP time */
|
|
|
|
/*
|
|
* Extract time string YYMMDDHHMMSSZ from ASN1 time structure.
|
|
* Note that the YY, MM, DD fields start with one, the HH, MM,
|
|
* SS fiels start with zero and the Z character should be 'Z'
|
|
* for UTC. Also note that years less than 50 map to years
|
|
* greater than 100. Dontcha love ASN.1? Better than MIL-188.
|
|
*/
|
|
if (asn1time->length > 13)
|
|
return ((u_long)(~0)); /* We can't use -1 here. It's invalid */
|
|
|
|
v = (char *)asn1time->data;
|
|
tm.tm_year = (v[0] - '0') * 10 + v[1] - '0';
|
|
if (tm.tm_year < 50)
|
|
tm.tm_year += 100;
|
|
tm.tm_mon = (v[2] - '0') * 10 + v[3] - '0' - 1;
|
|
tm.tm_mday = (v[4] - '0') * 10 + v[5] - '0';
|
|
tm.tm_hour = (v[6] - '0') * 10 + v[7] - '0';
|
|
tm.tm_min = (v[8] - '0') * 10 + v[9] - '0';
|
|
tm.tm_sec = (v[10] - '0') * 10 + v[11] - '0';
|
|
tm.tm_wday = 0;
|
|
tm.tm_yday = 0;
|
|
tm.tm_isdst = 0;
|
|
return (timegm(&tm) + JAN_1970);
|
|
}
|
|
|
|
|
|
/*
|
|
* bigdig() - compute a BIGNUM MD5 hash of a BIGNUM number.
|
|
*/
|
|
static int
|
|
bighash(
|
|
BIGNUM *bn, /* BIGNUM * from */
|
|
BIGNUM *bk /* BIGNUM * to */
|
|
)
|
|
{
|
|
EVP_MD_CTX ctx; /* message digest context */
|
|
u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
|
|
u_char *ptr; /* a BIGNUM as binary string */
|
|
u_int len;
|
|
|
|
len = BN_num_bytes(bn);
|
|
ptr = emalloc(len);
|
|
BN_bn2bin(bn, ptr);
|
|
EVP_DigestInit(&ctx, EVP_md5());
|
|
EVP_DigestUpdate(&ctx, ptr, len);
|
|
EVP_DigestFinal(&ctx, dgst, &len);
|
|
BN_bin2bn(dgst, len, bk);
|
|
|
|
/* XXX MEMLEAK? free ptr? */
|
|
|
|
return (1);
|
|
}
|
|
|
|
|
|
/*
|
|
***********************************************************************
|
|
* *
|
|
* The following routines implement the Schnorr (IFF) identity scheme *
|
|
* *
|
|
***********************************************************************
|
|
*
|
|
* The Schnorr (IFF) identity scheme is intended for use when
|
|
* the ntp-genkeys program does not generate the certificates used in
|
|
* the protocol and the group key cannot be conveyed in the certificate
|
|
* itself. For this purpose, new generations of IFF values must be
|
|
* securely transmitted to all members of the group before use. The
|
|
* scheme is self contained and independent of new generations of host
|
|
* keys, sign keys and certificates.
|
|
*
|
|
* The IFF identity scheme is based on DSA cryptography and algorithms
|
|
* described in Stinson p. 285. The IFF values hide in a DSA cuckoo
|
|
* structure, but only the primes and generator are used. The p is a
|
|
* 512-bit prime, q a 160-bit prime that divides p - 1 and is a qth root
|
|
* of 1 mod p; that is, g^q = 1 mod p. The TA rolls primvate random
|
|
* group key b disguised as a DSA structure member, then computes public
|
|
* key g^(q - b). These values are shared only among group members and
|
|
* never revealed in messages. Alice challenges Bob to confirm identity
|
|
* using the protocol described below.
|
|
*
|
|
* How it works
|
|
*
|
|
* The scheme goes like this. Both Alice and Bob have the public primes
|
|
* p, q and generator g. The TA gives private key b to Bob and public
|
|
* key v = g^(q - a) mod p to Alice.
|
|
*
|
|
* Alice rolls new random challenge r and sends to Bob in the IFF
|
|
* request message. Bob rolls new random k, then computes y = k + b r
|
|
* mod q and x = g^k mod p and sends (y, hash(x)) to Alice in the
|
|
* response message. Besides making the response shorter, the hash makes
|
|
* it effectivey impossible for an intruder to solve for b by observing
|
|
* a number of these messages.
|
|
*
|
|
* Alice receives the response and computes g^y v^r mod p. After a bit
|
|
* of algebra, this simplifies to g^k. If the hash of this result
|
|
* matches hash(x), Alice knows that Bob has the group key b. The signed
|
|
* response binds this knowledge to Bob's private key and the public key
|
|
* previously received in his certificate.
|
|
*
|
|
* crypto_alice - construct Alice's challenge in IFF scheme
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_ID bad or missing group key
|
|
*/
|
|
static int
|
|
crypto_alice(
|
|
struct peer *peer, /* peer pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
DSA *dsa; /* IFF parameters */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp;
|
|
u_int len;
|
|
|
|
/*
|
|
* The identity parameters must have correct format and content.
|
|
*/
|
|
if (peer->ident_pkey == NULL)
|
|
return (XEVNT_ID);
|
|
|
|
if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
|
|
msyslog(LOG_INFO, "crypto_alice: defective key");
|
|
return (XEVNT_PUB);
|
|
}
|
|
|
|
/*
|
|
* Roll new random r (0 < r < q). The OpenSSL library has a bug
|
|
* omitting BN_rand_range, so we have to do it the hard way.
|
|
*/
|
|
bctx = BN_CTX_new();
|
|
len = BN_num_bytes(dsa->q);
|
|
if (peer->iffval != NULL)
|
|
BN_free(peer->iffval);
|
|
peer->iffval = BN_new();
|
|
BN_rand(peer->iffval, len * 8, -1, 1); /* r */
|
|
BN_mod(peer->iffval, peer->iffval, dsa->q, bctx);
|
|
BN_CTX_free(bctx);
|
|
|
|
/*
|
|
* Sign and send to Bob. The filestamp is from the local file.
|
|
*/
|
|
tstamp = crypto_time();
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = htonl(peer->fstamp);
|
|
vp->vallen = htonl(len);
|
|
vp->ptr = emalloc(len);
|
|
BN_bn2bin(peer->iffval, vp->ptr);
|
|
vp->siglen = 0;
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_bob - construct Bob's response to Alice's challenge
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_ID bad or missing group key
|
|
* XEVNT_ERR protocol error
|
|
* XEVNT_PER host expired certificate
|
|
*/
|
|
static int
|
|
crypto_bob(
|
|
struct exten *ep, /* extension pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
DSA *dsa; /* IFF parameters */
|
|
DSA_SIG *sdsa; /* DSA signature context fake */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp; /* NTP timestamp */
|
|
BIGNUM *bn, *bk, *r;
|
|
u_char *ptr;
|
|
u_int len;
|
|
|
|
/*
|
|
* If the IFF parameters are not valid, something awful
|
|
* happened or we are being tormented.
|
|
*/
|
|
if (iffpar_pkey == NULL) {
|
|
msyslog(LOG_INFO, "crypto_bob: scheme unavailable");
|
|
return (XEVNT_ID);
|
|
}
|
|
dsa = iffpar_pkey->pkey.dsa;
|
|
|
|
/*
|
|
* Extract r from the challenge.
|
|
*/
|
|
len = ntohl(ep->vallen);
|
|
if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_bob %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_ERR);
|
|
}
|
|
|
|
/*
|
|
* Bob rolls random k (0 < k < q), computes y = k + b r mod q
|
|
* and x = g^k mod p, then sends (y, hash(x)) to Alice.
|
|
*/
|
|
bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
|
|
sdsa = DSA_SIG_new();
|
|
BN_rand(bk, len * 8, -1, 1); /* k */
|
|
BN_mod_mul(bn, dsa->priv_key, r, dsa->q, bctx); /* b r mod q */
|
|
BN_add(bn, bn, bk);
|
|
BN_mod(bn, bn, dsa->q, bctx); /* k + b r mod q */
|
|
sdsa->r = BN_dup(bn);
|
|
BN_mod_exp(bk, dsa->g, bk, dsa->p, bctx); /* g^k mod p */
|
|
bighash(bk, bk);
|
|
sdsa->s = BN_dup(bk);
|
|
BN_CTX_free(bctx);
|
|
BN_free(r); BN_free(bn); BN_free(bk);
|
|
|
|
/*
|
|
* Encode the values in ASN.1 and sign.
|
|
*/
|
|
tstamp = crypto_time();
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = htonl(if_fstamp);
|
|
len = i2d_DSA_SIG(sdsa, NULL);
|
|
if (len <= 0) {
|
|
msyslog(LOG_ERR, "crypto_bob %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
DSA_SIG_free(sdsa);
|
|
return (XEVNT_ERR);
|
|
}
|
|
vp->vallen = htonl(len);
|
|
ptr = emalloc(len);
|
|
vp->ptr = ptr;
|
|
i2d_DSA_SIG(sdsa, &ptr);
|
|
DSA_SIG_free(sdsa);
|
|
vp->siglen = 0;
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_iff - verify Bob's response to Alice's challenge
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_ID bad or missing group key
|
|
* XEVNT_FSP bad filestamp
|
|
*/
|
|
int
|
|
crypto_iff(
|
|
struct exten *ep, /* extension pointer */
|
|
struct peer *peer /* peer structure pointer */
|
|
)
|
|
{
|
|
DSA *dsa; /* IFF parameters */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
DSA_SIG *sdsa; /* DSA parameters */
|
|
BIGNUM *bn, *bk;
|
|
u_int len;
|
|
const u_char *ptr;
|
|
int temp;
|
|
|
|
/*
|
|
* If the IFF parameters are not valid or no challenge was sent,
|
|
* something awful happened or we are being tormented.
|
|
*/
|
|
if (peer->ident_pkey == NULL) {
|
|
msyslog(LOG_INFO, "crypto_iff: scheme unavailable");
|
|
return (XEVNT_ID);
|
|
}
|
|
if (ntohl(ep->fstamp) != peer->fstamp) {
|
|
msyslog(LOG_INFO, "crypto_iff: invalid filestamp %u",
|
|
ntohl(ep->fstamp));
|
|
return (XEVNT_FSP);
|
|
}
|
|
if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
|
|
msyslog(LOG_INFO, "crypto_iff: defective key");
|
|
return (XEVNT_PUB);
|
|
}
|
|
if (peer->iffval == NULL) {
|
|
msyslog(LOG_INFO, "crypto_iff: missing challenge");
|
|
return (XEVNT_ID);
|
|
}
|
|
|
|
/*
|
|
* Extract the k + b r and g^k values from the response.
|
|
*/
|
|
bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
|
|
len = ntohl(ep->vallen);
|
|
ptr = (const u_char *)ep->pkt;
|
|
if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_iff %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_ERR);
|
|
}
|
|
|
|
/*
|
|
* Compute g^(k + b r) g^(q - b)r mod p.
|
|
*/
|
|
BN_mod_exp(bn, dsa->pub_key, peer->iffval, dsa->p, bctx);
|
|
BN_mod_exp(bk, dsa->g, sdsa->r, dsa->p, bctx);
|
|
BN_mod_mul(bn, bn, bk, dsa->p, bctx);
|
|
|
|
/*
|
|
* Verify the hash of the result matches hash(x).
|
|
*/
|
|
bighash(bn, bn);
|
|
temp = BN_cmp(bn, sdsa->s);
|
|
BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
|
|
BN_free(peer->iffval);
|
|
peer->iffval = NULL;
|
|
DSA_SIG_free(sdsa);
|
|
if (temp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
else
|
|
return (XEVNT_ID);
|
|
}
|
|
|
|
|
|
/*
|
|
***********************************************************************
|
|
* *
|
|
* The following routines implement the Guillou-Quisquater (GQ) *
|
|
* identity scheme *
|
|
* *
|
|
***********************************************************************
|
|
*
|
|
* The Guillou-Quisquater (GQ) identity scheme is intended for use when
|
|
* the ntp-genkeys program generates the certificates used in the
|
|
* protocol and the group key can be conveyed in a certificate extension
|
|
* field. The scheme is self contained and independent of new
|
|
* generations of host keys, sign keys and certificates.
|
|
*
|
|
* The GQ identity scheme is based on RSA cryptography and algorithms
|
|
* described in Stinson p. 300 (with errors). The GQ values hide in a
|
|
* RSA cuckoo structure, but only the modulus is used. The 512-bit
|
|
* public modulus is n = p q, where p and q are secret large primes. The
|
|
* TA rolls random group key b disguised as a RSA structure member.
|
|
* Except for the public key, these values are shared only among group
|
|
* members and never revealed in messages.
|
|
*
|
|
* When rolling new certificates, Bob recomputes the private and
|
|
* public keys. The private key u is a random roll, while the public key
|
|
* is the inverse obscured by the group key v = (u^-1)^b. These values
|
|
* replace the private and public keys normally generated by the RSA
|
|
* scheme. Alice challenges Bob to confirm identity using the protocol
|
|
* described below.
|
|
*
|
|
* How it works
|
|
*
|
|
* The scheme goes like this. Both Alice and Bob have the same modulus n
|
|
* and some random b as the group key. These values are computed and
|
|
* distributed in advance via secret means, although only the group key
|
|
* b is truly secret. Each has a private random private key u and public
|
|
* key (u^-1)^b, although not necessarily the same ones. Bob and Alice
|
|
* can regenerate the key pair from time to time without affecting
|
|
* operations. The public key is conveyed on the certificate in an
|
|
* extension field; the private key is never revealed.
|
|
*
|
|
* Alice rolls new random challenge r and sends to Bob in the GQ
|
|
* request message. Bob rolls new random k, then computes y = k u^r mod
|
|
* n and x = k^b mod n and sends (y, hash(x)) to Alice in the response
|
|
* message. Besides making the response shorter, the hash makes it
|
|
* effectivey impossible for an intruder to solve for b by observing
|
|
* a number of these messages.
|
|
*
|
|
* Alice receives the response and computes y^b v^r mod n. After a bit
|
|
* of algebra, this simplifies to k^b. If the hash of this result
|
|
* matches hash(x), Alice knows that Bob has the group key b. The signed
|
|
* response binds this knowledge to Bob's private key and the public key
|
|
* previously received in his certificate.
|
|
*
|
|
* crypto_alice2 - construct Alice's challenge in GQ scheme
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_ID bad or missing group key
|
|
* XEVNT_PER host certificate expired
|
|
*/
|
|
static int
|
|
crypto_alice2(
|
|
struct peer *peer, /* peer pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
RSA *rsa; /* GQ parameters */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp;
|
|
u_int len;
|
|
|
|
/*
|
|
* The identity parameters must have correct format and content.
|
|
*/
|
|
if (peer->ident_pkey == NULL)
|
|
return (XEVNT_ID);
|
|
|
|
if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
|
|
msyslog(LOG_INFO, "crypto_alice2: defective key");
|
|
return (XEVNT_PUB);
|
|
}
|
|
|
|
/*
|
|
* Roll new random r (0 < r < n). The OpenSSL library has a bug
|
|
* omitting BN_rand_range, so we have to do it the hard way.
|
|
*/
|
|
bctx = BN_CTX_new();
|
|
len = BN_num_bytes(rsa->n);
|
|
if (peer->iffval != NULL)
|
|
BN_free(peer->iffval);
|
|
peer->iffval = BN_new();
|
|
BN_rand(peer->iffval, len * 8, -1, 1); /* r mod n */
|
|
BN_mod(peer->iffval, peer->iffval, rsa->n, bctx);
|
|
BN_CTX_free(bctx);
|
|
|
|
/*
|
|
* Sign and send to Bob. The filestamp is from the local file.
|
|
*/
|
|
tstamp = crypto_time();
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = htonl(peer->fstamp);
|
|
vp->vallen = htonl(len);
|
|
vp->ptr = emalloc(len);
|
|
BN_bn2bin(peer->iffval, vp->ptr);
|
|
vp->siglen = 0;
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_bob2 - construct Bob's response to Alice's challenge
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_ID bad or missing group key
|
|
* XEVNT_ERR protocol error
|
|
* XEVNT_PER host certificate expired
|
|
*/
|
|
static int
|
|
crypto_bob2(
|
|
struct exten *ep, /* extension pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
RSA *rsa; /* GQ parameters */
|
|
DSA_SIG *sdsa; /* DSA parameters */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp; /* NTP timestamp */
|
|
BIGNUM *r, *k, *g, *y;
|
|
u_char *ptr;
|
|
u_int len;
|
|
|
|
/*
|
|
* If the GQ parameters are not valid, something awful
|
|
* happened or we are being tormented.
|
|
*/
|
|
if (gqpar_pkey == NULL) {
|
|
msyslog(LOG_INFO, "crypto_bob2: scheme unavailable");
|
|
return (XEVNT_ID);
|
|
}
|
|
rsa = gqpar_pkey->pkey.rsa;
|
|
|
|
/*
|
|
* Extract r from the challenge.
|
|
*/
|
|
len = ntohl(ep->vallen);
|
|
if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_bob2 %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_ERR);
|
|
}
|
|
|
|
/*
|
|
* Bob rolls random k (0 < k < n), computes y = k u^r mod n and
|
|
* x = k^b mod n, then sends (y, hash(x)) to Alice.
|
|
*/
|
|
bctx = BN_CTX_new(); k = BN_new(); g = BN_new(); y = BN_new();
|
|
sdsa = DSA_SIG_new();
|
|
BN_rand(k, len * 8, -1, 1); /* k */
|
|
BN_mod(k, k, rsa->n, bctx);
|
|
BN_mod_exp(y, rsa->p, r, rsa->n, bctx); /* u^r mod n */
|
|
BN_mod_mul(y, k, y, rsa->n, bctx); /* k u^r mod n */
|
|
sdsa->r = BN_dup(y);
|
|
BN_mod_exp(g, k, rsa->e, rsa->n, bctx); /* k^b mod n */
|
|
bighash(g, g);
|
|
sdsa->s = BN_dup(g);
|
|
BN_CTX_free(bctx);
|
|
BN_free(r); BN_free(k); BN_free(g); BN_free(y);
|
|
|
|
/*
|
|
* Encode the values in ASN.1 and sign.
|
|
*/
|
|
tstamp = crypto_time();
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = htonl(gq_fstamp);
|
|
len = i2d_DSA_SIG(sdsa, NULL);
|
|
if (len <= 0) {
|
|
msyslog(LOG_ERR, "crypto_bob2 %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
DSA_SIG_free(sdsa);
|
|
return (XEVNT_ERR);
|
|
}
|
|
vp->vallen = htonl(len);
|
|
ptr = emalloc(len);
|
|
vp->ptr = ptr;
|
|
i2d_DSA_SIG(sdsa, &ptr);
|
|
DSA_SIG_free(sdsa);
|
|
vp->siglen = 0;
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_gq - verify Bob's response to Alice's challenge
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_ID bad or missing group keys
|
|
* XEVNT_ERR protocol error
|
|
* XEVNT_FSP bad filestamp
|
|
*/
|
|
int
|
|
crypto_gq(
|
|
struct exten *ep, /* extension pointer */
|
|
struct peer *peer /* peer structure pointer */
|
|
)
|
|
{
|
|
RSA *rsa; /* GQ parameters */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
DSA_SIG *sdsa; /* RSA signature context fake */
|
|
BIGNUM *y, *v;
|
|
const u_char *ptr;
|
|
u_int len;
|
|
int temp;
|
|
|
|
/*
|
|
* If the GQ parameters are not valid or no challenge was sent,
|
|
* something awful happened or we are being tormented.
|
|
*/
|
|
if (peer->ident_pkey == NULL) {
|
|
msyslog(LOG_INFO, "crypto_gq: scheme unavailable");
|
|
return (XEVNT_ID);
|
|
}
|
|
if (ntohl(ep->fstamp) != peer->fstamp) {
|
|
msyslog(LOG_INFO, "crypto_gq: invalid filestamp %u",
|
|
ntohl(ep->fstamp));
|
|
return (XEVNT_FSP);
|
|
}
|
|
if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
|
|
msyslog(LOG_INFO, "crypto_gq: defective key");
|
|
return (XEVNT_PUB);
|
|
}
|
|
if (peer->iffval == NULL) {
|
|
msyslog(LOG_INFO, "crypto_gq: missing challenge");
|
|
return (XEVNT_ID);
|
|
}
|
|
|
|
/*
|
|
* Extract the y = k u^r and hash(x = k^b) values from the
|
|
* response.
|
|
*/
|
|
bctx = BN_CTX_new(); y = BN_new(); v = BN_new();
|
|
len = ntohl(ep->vallen);
|
|
ptr = (const u_char *)ep->pkt;
|
|
if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_gq %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_ERR);
|
|
}
|
|
|
|
/*
|
|
* Compute v^r y^b mod n.
|
|
*/
|
|
BN_mod_exp(v, peer->grpkey, peer->iffval, rsa->n, bctx);
|
|
/* v^r mod n */
|
|
BN_mod_exp(y, sdsa->r, rsa->e, rsa->n, bctx); /* y^b mod n */
|
|
BN_mod_mul(y, v, y, rsa->n, bctx); /* v^r y^b mod n */
|
|
|
|
/*
|
|
* Verify the hash of the result matches hash(x).
|
|
*/
|
|
bighash(y, y);
|
|
temp = BN_cmp(y, sdsa->s);
|
|
BN_CTX_free(bctx); BN_free(y); BN_free(v);
|
|
BN_free(peer->iffval);
|
|
peer->iffval = NULL;
|
|
DSA_SIG_free(sdsa);
|
|
if (temp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
else
|
|
return (XEVNT_ID);
|
|
}
|
|
|
|
|
|
/*
|
|
***********************************************************************
|
|
* *
|
|
* The following routines implement the Mu-Varadharajan (MV) identity *
|
|
* scheme *
|
|
* *
|
|
***********************************************************************
|
|
*/
|
|
/*
|
|
* The Mu-Varadharajan (MV) cryptosystem was originally intended when
|
|
* servers broadcast messages to clients, but clients never send
|
|
* messages to servers. There is one encryption key for the server and a
|
|
* separate decryption key for each client. It operated something like a
|
|
* pay-per-view satellite broadcasting system where the session key is
|
|
* encrypted by the broadcaster and the decryption keys are held in a
|
|
* tamperproof set-top box.
|
|
*
|
|
* The MV parameters and private encryption key hide in a DSA cuckoo
|
|
* structure which uses the same parameters, but generated in a
|
|
* different way. The values are used in an encryption scheme similar to
|
|
* El Gamal cryptography and a polynomial formed from the expansion of
|
|
* product terms (x - x[j]), as described in Mu, Y., and V.
|
|
* Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
|
|
* 223-231. The paper has significant errors and serious omissions.
|
|
*
|
|
* Let q be the product of n distinct primes s'[j] (j = 1...n), where
|
|
* each s'[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
|
|
* that q and each s'[j] divide p - 1 and p has M = n * m + 1
|
|
* significant bits. The elements x mod q of Zq with the elements 2 and
|
|
* the primes removed form a field Zq* valid for polynomial arithetic.
|
|
* Let g be a generator of Zp; that is, gcd(g, p - 1) = 1 and g^q = 1
|
|
* mod p. We expect M to be in the 500-bit range and n relatively small,
|
|
* like 25, so the likelihood of a randomly generated element of x mod q
|
|
* of Zq colliding with a factor of p - 1 is very small and can be
|
|
* avoided. Associated with each s'[j] is an element s[j] such that s[j]
|
|
* s'[j] = s'[j] mod q. We find s[j] as the quotient (q + s'[j]) /
|
|
* s'[j]. These are the parameters of the scheme and they are expensive
|
|
* to compute.
|
|
*
|
|
* We set up an instance of the scheme as follows. A set of random
|
|
* values x[j] mod q (j = 1...n), are generated as the zeros of a
|
|
* polynomial of order n. The product terms (x - x[j]) are expanded to
|
|
* form coefficients a[i] mod q (i = 0...n) in powers of x. These are
|
|
* used as exponents of the generator g mod p to generate the private
|
|
* encryption key A. The pair (gbar, ghat) of public server keys and the
|
|
* pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
|
|
* to construct the decryption keys. The devil is in the details.
|
|
*
|
|
* The distinguishing characteristic of this scheme is the capability to
|
|
* revoke keys. Included in the calculation of E, gbar and ghat is the
|
|
* product s = prod(s'[j]) (j = 1...n) above. If the factor s'[j] is
|
|
* subsequently removed from the product and E, gbar and ghat
|
|
* recomputed, the jth client will no longer be able to compute E^-1 and
|
|
* thus unable to decrypt the block.
|
|
*
|
|
* How it works
|
|
*
|
|
* The scheme goes like this. Bob has the server values (p, A, q, gbar,
|
|
* ghat) and Alice the client values (p, xbar, xhat).
|
|
*
|
|
* Alice rolls new random challenge r (0 < r < p) and sends to Bob in
|
|
* the MV request message. Bob rolls new random k (0 < k < q), encrypts
|
|
* y = A^k mod p (a permutation) and sends (hash(y), gbar^k, ghat^k) to
|
|
* Alice.
|
|
*
|
|
* Alice receives the response and computes the decryption key (the
|
|
* inverse permutation) from previously obtained (xbar, xhat) and
|
|
* (gbar^k, ghat^k) in the message. She computes the inverse, which is
|
|
* unique by reasons explained in the ntp-keygen.c program sources. If
|
|
* the hash of this result matches hash(y), Alice knows that Bob has the
|
|
* group key b. The signed response binds this knowledge to Bob's
|
|
* private key and the public key previously received in his
|
|
* certificate.
|
|
*
|
|
* crypto_alice3 - construct Alice's challenge in MV scheme
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_ID bad or missing group key
|
|
* XEVNT_PER host certificate expired
|
|
*/
|
|
static int
|
|
crypto_alice3(
|
|
struct peer *peer, /* peer pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
DSA *dsa; /* MV parameters */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp;
|
|
u_int len;
|
|
|
|
/*
|
|
* The identity parameters must have correct format and content.
|
|
*/
|
|
if (peer->ident_pkey == NULL)
|
|
return (XEVNT_ID);
|
|
|
|
if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
|
|
msyslog(LOG_INFO, "crypto_alice3: defective key");
|
|
return (XEVNT_PUB);
|
|
}
|
|
|
|
/*
|
|
* Roll new random r (0 < r < q). The OpenSSL library has a bug
|
|
* omitting BN_rand_range, so we have to do it the hard way.
|
|
*/
|
|
bctx = BN_CTX_new();
|
|
len = BN_num_bytes(dsa->p);
|
|
if (peer->iffval != NULL)
|
|
BN_free(peer->iffval);
|
|
peer->iffval = BN_new();
|
|
BN_rand(peer->iffval, len * 8, -1, 1); /* r */
|
|
BN_mod(peer->iffval, peer->iffval, dsa->p, bctx);
|
|
BN_CTX_free(bctx);
|
|
|
|
/*
|
|
* Sign and send to Bob. The filestamp is from the local file.
|
|
*/
|
|
tstamp = crypto_time();
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = htonl(peer->fstamp);
|
|
vp->vallen = htonl(len);
|
|
vp->ptr = emalloc(len);
|
|
BN_bn2bin(peer->iffval, vp->ptr);
|
|
vp->siglen = 0;
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_bob3 - construct Bob's response to Alice's challenge
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_ERR protocol error
|
|
* XEVNT_PER host certificate expired
|
|
*/
|
|
static int
|
|
crypto_bob3(
|
|
struct exten *ep, /* extension pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
DSA *dsa; /* MV parameters */
|
|
DSA *sdsa; /* DSA signature context fake */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
EVP_MD_CTX ctx; /* signature context */
|
|
tstamp_t tstamp; /* NTP timestamp */
|
|
BIGNUM *r, *k, *u;
|
|
u_char *ptr;
|
|
u_int len;
|
|
|
|
/*
|
|
* If the MV parameters are not valid, something awful
|
|
* happened or we are being tormented.
|
|
*/
|
|
if (mvpar_pkey == NULL) {
|
|
msyslog(LOG_INFO, "crypto_bob3: scheme unavailable");
|
|
return (XEVNT_ID);
|
|
}
|
|
dsa = mvpar_pkey->pkey.dsa;
|
|
|
|
/*
|
|
* Extract r from the challenge.
|
|
*/
|
|
len = ntohl(ep->vallen);
|
|
if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_bob3 %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_ERR);
|
|
}
|
|
|
|
/*
|
|
* Bob rolls random k (0 < k < q), making sure it is not a
|
|
* factor of q. He then computes y = A^k r and sends (hash(y),
|
|
* gbar^k, ghat^k) to Alice.
|
|
*/
|
|
bctx = BN_CTX_new(); k = BN_new(); u = BN_new();
|
|
sdsa = DSA_new();
|
|
sdsa->p = BN_new(); sdsa->q = BN_new(); sdsa->g = BN_new();
|
|
while (1) {
|
|
BN_rand(k, BN_num_bits(dsa->q), 0, 0);
|
|
BN_mod(k, k, dsa->q, bctx);
|
|
BN_gcd(u, k, dsa->q, bctx);
|
|
if (BN_is_one(u))
|
|
break;
|
|
}
|
|
BN_mod_exp(u, dsa->g, k, dsa->p, bctx); /* A r */
|
|
BN_mod_mul(u, u, r, dsa->p, bctx);
|
|
bighash(u, sdsa->p);
|
|
BN_mod_exp(sdsa->q, dsa->priv_key, k, dsa->p, bctx); /* gbar */
|
|
BN_mod_exp(sdsa->g, dsa->pub_key, k, dsa->p, bctx); /* ghat */
|
|
BN_CTX_free(bctx); BN_free(k); BN_free(r); BN_free(u);
|
|
|
|
/*
|
|
* Encode the values in ASN.1 and sign.
|
|
*/
|
|
tstamp = crypto_time();
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = htonl(mv_fstamp);
|
|
len = i2d_DSAparams(sdsa, NULL);
|
|
if (len <= 0) {
|
|
msyslog(LOG_ERR, "crypto_bob3 %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
DSA_free(sdsa);
|
|
return (XEVNT_ERR);
|
|
}
|
|
vp->vallen = htonl(len);
|
|
ptr = emalloc(len);
|
|
vp->ptr = ptr;
|
|
i2d_DSAparams(sdsa, &ptr);
|
|
DSA_free(sdsa);
|
|
vp->siglen = 0;
|
|
if (tstamp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_mv - verify Bob's response to Alice's challenge
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_ID bad or missing group key
|
|
* XEVNT_ERR protocol error
|
|
* XEVNT_FSP bad filestamp
|
|
*/
|
|
int
|
|
crypto_mv(
|
|
struct exten *ep, /* extension pointer */
|
|
struct peer *peer /* peer structure pointer */
|
|
)
|
|
{
|
|
DSA *dsa; /* MV parameters */
|
|
DSA *sdsa; /* DSA parameters */
|
|
BN_CTX *bctx; /* BIGNUM context */
|
|
BIGNUM *k, *u, *v;
|
|
u_int len;
|
|
const u_char *ptr;
|
|
int temp;
|
|
|
|
/*
|
|
* If the MV parameters are not valid or no challenge was sent,
|
|
* something awful happened or we are being tormented.
|
|
*/
|
|
if (peer->ident_pkey == NULL) {
|
|
msyslog(LOG_INFO, "crypto_mv: scheme unavailable");
|
|
return (XEVNT_ID);
|
|
}
|
|
if (ntohl(ep->fstamp) != peer->fstamp) {
|
|
msyslog(LOG_INFO, "crypto_mv: invalid filestamp %u",
|
|
ntohl(ep->fstamp));
|
|
return (XEVNT_FSP);
|
|
}
|
|
if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
|
|
msyslog(LOG_INFO, "crypto_mv: defective key");
|
|
return (XEVNT_PUB);
|
|
}
|
|
if (peer->iffval == NULL) {
|
|
msyslog(LOG_INFO, "crypto_mv: missing challenge");
|
|
return (XEVNT_ID);
|
|
}
|
|
|
|
/*
|
|
* Extract the (hash(y), gbar, ghat) values from the response.
|
|
*/
|
|
bctx = BN_CTX_new(); k = BN_new(); u = BN_new(); v = BN_new();
|
|
len = ntohl(ep->vallen);
|
|
ptr = (const u_char *)ep->pkt;
|
|
if ((sdsa = d2i_DSAparams(NULL, &ptr, len)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_mv %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_ERR);
|
|
}
|
|
|
|
/*
|
|
* Compute (gbar^xhat ghat^xbar)^-1 mod p.
|
|
*/
|
|
BN_mod_exp(u, sdsa->q, dsa->pub_key, dsa->p, bctx);
|
|
BN_mod_exp(v, sdsa->g, dsa->priv_key, dsa->p, bctx);
|
|
BN_mod_mul(u, u, v, dsa->p, bctx);
|
|
BN_mod_inverse(u, u, dsa->p, bctx);
|
|
BN_mod_mul(v, u, peer->iffval, dsa->p, bctx);
|
|
|
|
/*
|
|
* The result should match the hash of r mod p.
|
|
*/
|
|
bighash(v, v);
|
|
temp = BN_cmp(v, sdsa->p);
|
|
BN_CTX_free(bctx); BN_free(k); BN_free(u); BN_free(v);
|
|
BN_free(peer->iffval);
|
|
peer->iffval = NULL;
|
|
DSA_free(sdsa);
|
|
if (temp == 0)
|
|
return (XEVNT_OK);
|
|
|
|
else
|
|
return (XEVNT_ID);
|
|
}
|
|
|
|
|
|
/*
|
|
***********************************************************************
|
|
* *
|
|
* The following routines are used to manipulate certificates *
|
|
* *
|
|
***********************************************************************
|
|
*/
|
|
/*
|
|
* cert_parse - parse x509 certificate and create info/value structures.
|
|
*
|
|
* The server certificate includes the version number, issuer name,
|
|
* subject name, public key and valid date interval. If the issuer name
|
|
* is the same as the subject name, the certificate is self signed and
|
|
* valid only if the server is configured as trustable. If the names are
|
|
* different, another issuer has signed the server certificate and
|
|
* vouched for it. In this case the server certificate is valid if
|
|
* verified by the issuer public key.
|
|
*
|
|
* Returns certificate info/value pointer if valid, NULL if not.
|
|
*/
|
|
struct cert_info * /* certificate information structure */
|
|
cert_parse(
|
|
u_char *asn1cert, /* X509 certificate */
|
|
u_int len, /* certificate length */
|
|
tstamp_t fstamp /* filestamp */
|
|
)
|
|
{
|
|
X509 *cert; /* X509 certificate */
|
|
X509_EXTENSION *ext; /* X509v3 extension */
|
|
struct cert_info *ret; /* certificate info/value */
|
|
BIO *bp;
|
|
X509V3_EXT_METHOD *method;
|
|
char pathbuf[MAXFILENAME];
|
|
u_char *uptr;
|
|
char *ptr;
|
|
int temp, cnt, i;
|
|
|
|
/*
|
|
* Decode ASN.1 objects and construct certificate structure.
|
|
*/
|
|
uptr = asn1cert;
|
|
if ((cert = d2i_X509(NULL, &uptr, len)) == NULL) {
|
|
msyslog(LOG_ERR, "cert_parse %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Extract version, subject name and public key.
|
|
*/
|
|
ret = emalloc(sizeof(struct cert_info));
|
|
memset(ret, 0, sizeof(struct cert_info));
|
|
if ((ret->pkey = X509_get_pubkey(cert)) == NULL) {
|
|
msyslog(LOG_ERR, "cert_parse %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
cert_free(ret);
|
|
X509_free(cert);
|
|
return (NULL);
|
|
}
|
|
ret->version = X509_get_version(cert);
|
|
X509_NAME_oneline(X509_get_subject_name(cert), pathbuf,
|
|
MAXFILENAME - 1);
|
|
ptr = strstr(pathbuf, "CN=");
|
|
if (ptr == NULL) {
|
|
msyslog(LOG_INFO, "cert_parse: invalid subject %s",
|
|
pathbuf);
|
|
cert_free(ret);
|
|
X509_free(cert);
|
|
return (NULL);
|
|
}
|
|
ret->subject = emalloc(strlen(ptr) + 1);
|
|
strcpy(ret->subject, ptr + 3);
|
|
|
|
/*
|
|
* Extract remaining objects. Note that the NTP serial number is
|
|
* the NTP seconds at the time of signing, but this might not be
|
|
* the case for other authority. We don't bother to check the
|
|
* objects at this time, since the real crunch can happen only
|
|
* when the time is valid but not yet certificated.
|
|
*/
|
|
ret->nid = OBJ_obj2nid(cert->cert_info->signature->algorithm);
|
|
ret->digest = (const EVP_MD *)EVP_get_digestbynid(ret->nid);
|
|
ret->serial =
|
|
(u_long)ASN1_INTEGER_get(X509_get_serialNumber(cert));
|
|
X509_NAME_oneline(X509_get_issuer_name(cert), pathbuf,
|
|
MAXFILENAME);
|
|
if ((ptr = strstr(pathbuf, "CN=")) == NULL) {
|
|
msyslog(LOG_INFO, "cert_parse: invalid issuer %s",
|
|
pathbuf);
|
|
cert_free(ret);
|
|
X509_free(cert);
|
|
return (NULL);
|
|
}
|
|
ret->issuer = emalloc(strlen(ptr) + 1);
|
|
strcpy(ret->issuer, ptr + 3);
|
|
ret->first = asn2ntp(X509_get_notBefore(cert));
|
|
ret->last = asn2ntp(X509_get_notAfter(cert));
|
|
|
|
/*
|
|
* Extract extension fields. These are ad hoc ripoffs of
|
|
* currently assigned functions and will certainly be changed
|
|
* before prime time.
|
|
*/
|
|
cnt = X509_get_ext_count(cert);
|
|
for (i = 0; i < cnt; i++) {
|
|
ext = X509_get_ext(cert, i);
|
|
method = X509V3_EXT_get(ext);
|
|
temp = OBJ_obj2nid(ext->object);
|
|
switch (temp) {
|
|
|
|
/*
|
|
* If a key_usage field is present, we decode whether
|
|
* this is a trusted or private certificate. This is
|
|
* dorky; all we want is to compare NIDs, but OpenSSL
|
|
* insists on BIO text strings.
|
|
*/
|
|
case NID_ext_key_usage:
|
|
bp = BIO_new(BIO_s_mem());
|
|
X509V3_EXT_print(bp, ext, 0, 0);
|
|
BIO_gets(bp, pathbuf, MAXFILENAME);
|
|
BIO_free(bp);
|
|
#if DEBUG
|
|
if (debug)
|
|
printf("cert_parse: %s: %s\n",
|
|
OBJ_nid2ln(temp), pathbuf);
|
|
#endif
|
|
if (strcmp(pathbuf, "Trust Root") == 0)
|
|
ret->flags |= CERT_TRUST;
|
|
else if (strcmp(pathbuf, "Private") == 0)
|
|
ret->flags |= CERT_PRIV;
|
|
break;
|
|
|
|
/*
|
|
* If a NID_subject_key_identifier field is present, it
|
|
* contains the GQ public key.
|
|
*/
|
|
case NID_subject_key_identifier:
|
|
ret->grplen = ext->value->length - 2;
|
|
ret->grpkey = emalloc(ret->grplen);
|
|
memcpy(ret->grpkey, &ext->value->data[2],
|
|
ret->grplen);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If certificate is self signed, verify signature.
|
|
*/
|
|
if (strcmp(ret->subject, ret->issuer) == 0) {
|
|
if (!X509_verify(cert, ret->pkey)) {
|
|
msyslog(LOG_INFO,
|
|
"cert_parse: signature not verified %s",
|
|
pathbuf);
|
|
cert_free(ret);
|
|
X509_free(cert);
|
|
return (NULL);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Verify certificate valid times. Note that certificates cannot
|
|
* be retroactive.
|
|
*/
|
|
if (ret->first > ret->last || ret->first < fstamp) {
|
|
msyslog(LOG_INFO,
|
|
"cert_parse: invalid certificate %s first %u last %u fstamp %u",
|
|
ret->subject, ret->first, ret->last, fstamp);
|
|
cert_free(ret);
|
|
X509_free(cert);
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Build the value structure to sign and send later.
|
|
*/
|
|
ret->cert.fstamp = htonl(fstamp);
|
|
ret->cert.vallen = htonl(len);
|
|
ret->cert.ptr = emalloc(len);
|
|
memcpy(ret->cert.ptr, asn1cert, len);
|
|
#ifdef DEBUG
|
|
if (debug > 1)
|
|
X509_print_fp(stdout, cert);
|
|
#endif
|
|
X509_free(cert);
|
|
return (ret);
|
|
}
|
|
|
|
|
|
/*
|
|
* cert_sign - sign x509 certificate equest and update value structure.
|
|
*
|
|
* The certificate request includes a copy of the host certificate,
|
|
* which includes the version number, subject name and public key of the
|
|
* host. The resulting certificate includes these values plus the
|
|
* serial number, issuer name and valid interval of the server. The
|
|
* valid interval extends from the current time to the same time one
|
|
* year hence. This may extend the life of the signed certificate beyond
|
|
* that of the signer certificate.
|
|
*
|
|
* It is convenient to use the NTP seconds of the current time as the
|
|
* serial number. In the value structure the timestamp is the current
|
|
* time and the filestamp is taken from the extension field. Note this
|
|
* routine is called only when the client clock is synchronized to a
|
|
* proventic source, so timestamp comparisons are valid.
|
|
*
|
|
* The host certificate is valid from the time it was generated for a
|
|
* period of one year. A signed certificate is valid from the time of
|
|
* signature for a period of one year, but only the host certificate (or
|
|
* sign certificate if used) is actually used to encrypt and decrypt
|
|
* signatures. The signature trail is built from the client via the
|
|
* intermediate servers to the trusted server. Each signature on the
|
|
* trail must be valid at the time of signature, but it could happen
|
|
* that a signer certificate expire before the signed certificate, which
|
|
* remains valid until its expiration.
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_PUB bad or missing public key
|
|
* XEVNT_CRT bad or missing certificate
|
|
* XEVNT_VFY certificate not verified
|
|
* XEVNT_PER host certificate expired
|
|
*/
|
|
static int
|
|
cert_sign(
|
|
struct exten *ep, /* extension field pointer */
|
|
struct value *vp /* value pointer */
|
|
)
|
|
{
|
|
X509 *req; /* X509 certificate request */
|
|
X509 *cert; /* X509 certificate */
|
|
X509_EXTENSION *ext; /* certificate extension */
|
|
ASN1_INTEGER *serial; /* serial number */
|
|
X509_NAME *subj; /* distinguished (common) name */
|
|
EVP_PKEY *pkey; /* public key */
|
|
EVP_MD_CTX ctx; /* message digest context */
|
|
tstamp_t tstamp; /* NTP timestamp */
|
|
u_int len;
|
|
u_char *ptr;
|
|
int i, temp;
|
|
|
|
/*
|
|
* Decode ASN.1 objects and construct certificate structure.
|
|
* Make sure the system clock is synchronized to a proventic
|
|
* source.
|
|
*/
|
|
tstamp = crypto_time();
|
|
if (tstamp == 0)
|
|
return (XEVNT_TSP);
|
|
|
|
if (tstamp < cinfo->first || tstamp > cinfo->last)
|
|
return (XEVNT_PER);
|
|
|
|
ptr = (u_char *)ep->pkt;
|
|
if ((req = d2i_X509(NULL, &ptr, ntohl(ep->vallen))) == NULL) {
|
|
msyslog(LOG_ERR, "cert_sign %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (XEVNT_CRT);
|
|
}
|
|
/*
|
|
* Extract public key and check for errors.
|
|
*/
|
|
if ((pkey = X509_get_pubkey(req)) == NULL) {
|
|
msyslog(LOG_ERR, "cert_sign %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
X509_free(req);
|
|
return (XEVNT_PUB);
|
|
}
|
|
|
|
/*
|
|
* Generate X509 certificate signed by this server. For this
|
|
* purpose the issuer name is the server name. Also copy any
|
|
* extensions that might be present.
|
|
*/
|
|
cert = X509_new();
|
|
X509_set_version(cert, X509_get_version(req));
|
|
serial = ASN1_INTEGER_new();
|
|
ASN1_INTEGER_set(serial, tstamp);
|
|
X509_set_serialNumber(cert, serial);
|
|
X509_gmtime_adj(X509_get_notBefore(cert), 0L);
|
|
X509_gmtime_adj(X509_get_notAfter(cert), YEAR);
|
|
subj = X509_get_issuer_name(cert);
|
|
X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
|
|
(u_char *)sys_hostname, strlen(sys_hostname), -1, 0);
|
|
subj = X509_get_subject_name(req);
|
|
X509_set_subject_name(cert, subj);
|
|
X509_set_pubkey(cert, pkey);
|
|
ext = X509_get_ext(req, 0);
|
|
temp = X509_get_ext_count(req);
|
|
for (i = 0; i < temp; i++) {
|
|
ext = X509_get_ext(req, i);
|
|
X509_add_ext(cert, ext, -1);
|
|
}
|
|
X509_free(req);
|
|
|
|
/*
|
|
* Sign and verify the certificate.
|
|
*/
|
|
X509_sign(cert, sign_pkey, sign_digest);
|
|
if (!X509_verify(cert, sign_pkey)) {
|
|
printf("cert_sign\n%s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
X509_free(cert);
|
|
return (XEVNT_VFY);
|
|
}
|
|
len = i2d_X509(cert, NULL);
|
|
|
|
/*
|
|
* Build and sign the value structure. We have to sign it here,
|
|
* since the response has to be returned right away. This is a
|
|
* clogging hazard.
|
|
*/
|
|
memset(vp, 0, sizeof(struct value));
|
|
vp->tstamp = htonl(tstamp);
|
|
vp->fstamp = ep->fstamp;
|
|
vp->vallen = htonl(len);
|
|
vp->ptr = emalloc(len);
|
|
ptr = vp->ptr;
|
|
i2d_X509(cert, &ptr);
|
|
vp->siglen = 0;
|
|
vp->sig = emalloc(sign_siglen);
|
|
EVP_SignInit(&ctx, sign_digest);
|
|
EVP_SignUpdate(&ctx, (u_char *)vp, 12);
|
|
EVP_SignUpdate(&ctx, vp->ptr, len);
|
|
if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
|
|
vp->siglen = htonl(len);
|
|
#ifdef DEBUG
|
|
if (debug > 1)
|
|
X509_print_fp(stdout, cert);
|
|
#endif
|
|
X509_free(cert);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* cert_valid - verify certificate with given public key
|
|
*
|
|
* This is pretty ugly, as the certificate has to be verified in the
|
|
* OpenSSL X509 structure, not in the DER format in the info/value
|
|
* structure.
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_VFY certificate not verified
|
|
*/
|
|
int
|
|
cert_valid(
|
|
struct cert_info *cinf, /* certificate information structure */
|
|
EVP_PKEY *pkey /* public key */
|
|
)
|
|
{
|
|
X509 *cert; /* X509 certificate */
|
|
u_char *ptr;
|
|
|
|
if (cinf->flags & CERT_SIGN)
|
|
return (XEVNT_OK);
|
|
|
|
ptr = (u_char *)cinf->cert.ptr;
|
|
cert = d2i_X509(NULL, &ptr, ntohl(cinf->cert.vallen));
|
|
if (cert == NULL || !X509_verify(cert, pkey))
|
|
return (XEVNT_VFY);
|
|
|
|
X509_free(cert);
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* cert - install certificate in certificate list
|
|
*
|
|
* This routine encodes an extension field into a certificate info/value
|
|
* structure. It searches the certificate list for duplicates and
|
|
* expunges whichever is older. It then searches the list for other
|
|
* certificates that might be verified by this latest one. Finally, it
|
|
* inserts this certificate first on the list.
|
|
*
|
|
* Returns
|
|
* XEVNT_OK success
|
|
* XEVNT_FSP bad or missing filestamp
|
|
* XEVNT_CRT bad or missing certificate
|
|
*/
|
|
int
|
|
cert_install(
|
|
struct exten *ep, /* cert info/value */
|
|
struct peer *peer /* peer structure */
|
|
)
|
|
{
|
|
struct cert_info *cp, *xp, *yp, **zp;
|
|
|
|
/*
|
|
* Parse and validate the signed certificate. If valid,
|
|
* construct the info/value structure; otherwise, scamper home.
|
|
*/
|
|
if ((cp = cert_parse((u_char *)ep->pkt, ntohl(ep->vallen),
|
|
ntohl(ep->fstamp))) == NULL)
|
|
return (XEVNT_CRT);
|
|
|
|
/*
|
|
* Scan certificate list looking for another certificate with
|
|
* the same subject and issuer. If another is found with the
|
|
* same or older filestamp, unlink it and return the goodies to
|
|
* the heap. If another is found with a later filestamp, discard
|
|
* the new one and leave the building.
|
|
*
|
|
* Make a note to study this issue again. An earlier certificate
|
|
* with a long lifetime might be overtaken by a later
|
|
* certificate with a short lifetime, thus invalidating the
|
|
* earlier signature. However, we gotta find a way to leak old
|
|
* stuff from the cache, so we do it anyway.
|
|
*/
|
|
yp = cp;
|
|
zp = &cinfo;
|
|
for (xp = cinfo; xp != NULL; xp = xp->link) {
|
|
if (strcmp(cp->subject, xp->subject) == 0 &&
|
|
strcmp(cp->issuer, xp->issuer) == 0) {
|
|
if (ntohl(cp->cert.fstamp) <=
|
|
ntohl(xp->cert.fstamp)) {
|
|
*zp = xp->link;;
|
|
cert_free(xp);
|
|
} else {
|
|
cert_free(cp);
|
|
return (XEVNT_FSP);
|
|
}
|
|
break;
|
|
}
|
|
zp = &xp->link;
|
|
}
|
|
yp->link = cinfo;
|
|
cinfo = yp;
|
|
|
|
/*
|
|
* Scan the certificate list to see if Y is signed by X. This is
|
|
* independent of order.
|
|
*/
|
|
for (yp = cinfo; yp != NULL; yp = yp->link) {
|
|
for (xp = cinfo; xp != NULL; xp = xp->link) {
|
|
|
|
/*
|
|
* If the issuer of certificate Y matches the
|
|
* subject of certificate X, verify the
|
|
* signature of Y using the public key of X. If
|
|
* so, X signs Y.
|
|
*/
|
|
if (strcmp(yp->issuer, xp->subject) != 0 ||
|
|
xp->flags & CERT_ERROR)
|
|
continue;
|
|
|
|
if (cert_valid(yp, xp->pkey) != XEVNT_OK) {
|
|
yp->flags |= CERT_ERROR;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* The signature Y is valid only if it begins
|
|
* during the lifetime of X; however, it is not
|
|
* necessarily an error, since some other
|
|
* certificate might sign Y.
|
|
*/
|
|
if (yp->first < xp->first || yp->first >
|
|
xp->last)
|
|
continue;
|
|
|
|
yp->flags |= CERT_SIGN;
|
|
|
|
/*
|
|
* If X is trusted, then Y is trusted. Note that
|
|
* we might stumble over a self-signed
|
|
* certificate that is not trusted, at least
|
|
* temporarily. This can happen when a dude
|
|
* first comes up, but has not synchronized the
|
|
* clock and had its certificate signed by its
|
|
* server. In case of broken certificate trail,
|
|
* this might result in a loop that could
|
|
* persist until timeout.
|
|
*/
|
|
if (!(xp->flags & (CERT_TRUST | CERT_VALID)))
|
|
continue;
|
|
|
|
yp->flags |= CERT_VALID;
|
|
|
|
/*
|
|
* If subject Y matches the server subject name,
|
|
* then Y has completed the certificate trail.
|
|
* Save the group key and light the valid bit.
|
|
*/
|
|
if (strcmp(yp->subject, peer->subject) != 0)
|
|
continue;
|
|
|
|
if (yp->grpkey != NULL) {
|
|
if (peer->grpkey != NULL)
|
|
BN_free(peer->grpkey);
|
|
peer->grpkey = BN_bin2bn(yp->grpkey,
|
|
yp->grplen, NULL);
|
|
}
|
|
peer->crypto |= CRYPTO_FLAG_VALID;
|
|
|
|
/*
|
|
* If the server has an an identity scheme,
|
|
* fetch the identity credentials. If not, the
|
|
* identity is verified only by the trusted
|
|
* certificate. The next signature will set the
|
|
* server proventic.
|
|
*/
|
|
if (peer->crypto & (CRYPTO_FLAG_GQ |
|
|
CRYPTO_FLAG_IFF | CRYPTO_FLAG_MV))
|
|
continue;
|
|
|
|
peer->crypto |= CRYPTO_FLAG_VRFY;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* That was awesome. Now update the timestamps and signatures.
|
|
*/
|
|
crypto_update();
|
|
return (XEVNT_OK);
|
|
}
|
|
|
|
|
|
/*
|
|
* cert_free - free certificate information structure
|
|
*/
|
|
void
|
|
cert_free(
|
|
struct cert_info *cinf /* certificate info/value structure */
|
|
)
|
|
{
|
|
if (cinf->pkey != NULL)
|
|
EVP_PKEY_free(cinf->pkey);
|
|
if (cinf->subject != NULL)
|
|
free(cinf->subject);
|
|
if (cinf->issuer != NULL)
|
|
free(cinf->issuer);
|
|
if (cinf->grpkey != NULL)
|
|
free(cinf->grpkey);
|
|
value_free(&cinf->cert);
|
|
free(cinf);
|
|
}
|
|
|
|
|
|
/*
|
|
***********************************************************************
|
|
* *
|
|
* The following routines are used only at initialization time *
|
|
* *
|
|
***********************************************************************
|
|
*/
|
|
/*
|
|
* crypto_key - load cryptographic parameters and keys from files
|
|
*
|
|
* This routine loads a PEM-encoded public/private key pair and extracts
|
|
* the filestamp from the file name.
|
|
*
|
|
* Returns public key pointer if valid, NULL if not. Side effect updates
|
|
* the filestamp if valid.
|
|
*/
|
|
static EVP_PKEY *
|
|
crypto_key(
|
|
char *cp, /* file name */
|
|
tstamp_t *fstamp /* filestamp */
|
|
)
|
|
{
|
|
FILE *str; /* file handle */
|
|
EVP_PKEY *pkey = NULL; /* public/private key */
|
|
char filename[MAXFILENAME]; /* name of key file */
|
|
char linkname[MAXFILENAME]; /* filestamp buffer) */
|
|
char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
|
|
char *ptr;
|
|
|
|
/*
|
|
* Open the key file. If the first character of the file name is
|
|
* not '/', prepend the keys directory string. If something goes
|
|
* wrong, abandon ship.
|
|
*/
|
|
if (*cp == '/')
|
|
strcpy(filename, cp);
|
|
else
|
|
snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
|
|
str = fopen(filename, "r");
|
|
if (str == NULL)
|
|
return (NULL);
|
|
|
|
/*
|
|
* Read the filestamp, which is contained in the first line.
|
|
*/
|
|
if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_key: no data %s\n",
|
|
filename);
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
if ((ptr = strrchr(ptr, '.')) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_key: no filestamp %s\n",
|
|
filename);
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
if (sscanf(++ptr, "%u", fstamp) != 1) {
|
|
msyslog(LOG_ERR, "crypto_key: invalid timestamp %s\n",
|
|
filename);
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Read and decrypt PEM-encoded private key.
|
|
*/
|
|
pkey = PEM_read_PrivateKey(str, NULL, NULL, passwd);
|
|
fclose(str);
|
|
if (pkey == NULL) {
|
|
msyslog(LOG_ERR, "crypto_key %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Leave tracks in the cryptostats.
|
|
*/
|
|
if ((ptr = strrchr(linkname, '\n')) != NULL)
|
|
*ptr = '\0';
|
|
snprintf(statstr, NTP_MAXSTRLEN, "%s mod %d", &linkname[2],
|
|
EVP_PKEY_size(pkey) * 8);
|
|
record_crypto_stats(NULL, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_key: %s\n", statstr);
|
|
if (debug > 1) {
|
|
if (pkey->type == EVP_PKEY_DSA)
|
|
DSA_print_fp(stdout, pkey->pkey.dsa, 0);
|
|
else
|
|
RSA_print_fp(stdout, pkey->pkey.rsa, 0);
|
|
}
|
|
#endif
|
|
return (pkey);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_cert - load certificate from file
|
|
*
|
|
* This routine loads a X.509 RSA or DSA certificate from a file and
|
|
* constructs a info/cert value structure for this machine. The
|
|
* structure includes a filestamp extracted from the file name. Later
|
|
* the certificate can be sent to another machine by request.
|
|
*
|
|
* Returns certificate info/value pointer if valid, NULL if not.
|
|
*/
|
|
static struct cert_info * /* certificate information */
|
|
crypto_cert(
|
|
char *cp /* file name */
|
|
)
|
|
{
|
|
struct cert_info *ret; /* certificate information */
|
|
FILE *str; /* file handle */
|
|
char filename[MAXFILENAME]; /* name of certificate file */
|
|
char linkname[MAXFILENAME]; /* filestamp buffer */
|
|
char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
|
|
tstamp_t fstamp; /* filestamp */
|
|
long len;
|
|
char *ptr;
|
|
char *name, *header;
|
|
u_char *data;
|
|
|
|
/*
|
|
* Open the certificate file. If the first character of the file
|
|
* name is not '/', prepend the keys directory string. If
|
|
* something goes wrong, abandon ship.
|
|
*/
|
|
if (*cp == '/')
|
|
strcpy(filename, cp);
|
|
else
|
|
snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
|
|
str = fopen(filename, "r");
|
|
if (str == NULL)
|
|
return (NULL);
|
|
|
|
/*
|
|
* Read the filestamp, which is contained in the first line.
|
|
*/
|
|
if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_cert: no data %s\n",
|
|
filename);
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
if ((ptr = strrchr(ptr, '.')) == NULL) {
|
|
msyslog(LOG_ERR, "crypto_cert: no filestamp %s\n",
|
|
filename);
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
if (sscanf(++ptr, "%u", &fstamp) != 1) {
|
|
msyslog(LOG_ERR, "crypto_cert: invalid filestamp %s\n",
|
|
filename);
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Read PEM-encoded certificate and install.
|
|
*/
|
|
if (!PEM_read(str, &name, &header, &data, &len)) {
|
|
msyslog(LOG_ERR, "crypto_cert %s\n",
|
|
ERR_error_string(ERR_get_error(), NULL));
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
free(header);
|
|
if (strcmp(name, "CERTIFICATE") !=0) {
|
|
msyslog(LOG_INFO, "crypto_cert: wrong PEM type %s",
|
|
name);
|
|
free(name);
|
|
free(data);
|
|
(void)fclose(str);
|
|
return (NULL);
|
|
}
|
|
free(name);
|
|
|
|
/*
|
|
* Parse certificate and generate info/value structure.
|
|
*/
|
|
ret = cert_parse(data, len, fstamp);
|
|
free(data);
|
|
(void)fclose(str);
|
|
if (ret == NULL)
|
|
return (NULL);
|
|
|
|
if ((ptr = strrchr(linkname, '\n')) != NULL)
|
|
*ptr = '\0';
|
|
snprintf(statstr, NTP_MAXSTRLEN,
|
|
"%s 0x%x len %lu", &linkname[2], ret->flags, len);
|
|
record_crypto_stats(NULL, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_cert: %s\n", statstr);
|
|
#endif
|
|
return (ret);
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_tai - load leapseconds table from file
|
|
*
|
|
* This routine loads the ERTS leapsecond file in NIST text format,
|
|
* converts to a value structure and extracts a filestamp from the file
|
|
* name. The data are used to establish the TAI offset from UTC, which
|
|
* is provided to the kernel if supported. Later the data can be sent to
|
|
* another machine on request.
|
|
*/
|
|
static void
|
|
crypto_tai(
|
|
char *cp /* file name */
|
|
)
|
|
{
|
|
FILE *str; /* file handle */
|
|
char buf[NTP_MAXSTRLEN]; /* file line buffer */
|
|
u_int32 leapsec[MAX_LEAP]; /* NTP time at leaps */
|
|
int offset; /* offset at leap (s) */
|
|
char filename[MAXFILENAME]; /* name of leapseconds file */
|
|
char linkname[MAXFILENAME]; /* file link (for filestamp) */
|
|
char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
|
|
tstamp_t fstamp; /* filestamp */
|
|
u_int len;
|
|
u_int32 *ptr;
|
|
char *dp;
|
|
int rval, i, j;
|
|
|
|
/*
|
|
* Open the file and discard comment lines. If the first
|
|
* character of the file name is not '/', prepend the keys
|
|
* directory string. If the file is not found, not to worry; it
|
|
* can be retrieved over the net. But, if it is found with
|
|
* errors, we crash and burn.
|
|
*/
|
|
if (*cp == '/')
|
|
strcpy(filename, cp);
|
|
else
|
|
snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
|
|
if ((str = fopen(filename, "r")) == NULL)
|
|
return;
|
|
|
|
/*
|
|
* Extract filestamp if present.
|
|
*/
|
|
rval = readlink(filename, linkname, MAXFILENAME - 1);
|
|
if (rval > 0) {
|
|
linkname[rval] = '\0';
|
|
dp = strrchr(linkname, '.');
|
|
} else {
|
|
dp = strrchr(filename, '.');
|
|
}
|
|
if (dp != NULL)
|
|
sscanf(++dp, "%u", &fstamp);
|
|
else
|
|
fstamp = 0;
|
|
tai_leap.fstamp = htonl(fstamp);
|
|
|
|
/*
|
|
* We are rather paranoid here, since an intruder might cause a
|
|
* coredump by infiltrating naughty values. Empty lines and
|
|
* comments are ignored. Other lines must begin with two
|
|
* integers followed by junk or comments. The first integer is
|
|
* the NTP seconds of leap insertion, the second is the offset
|
|
* of TAI relative to UTC after that insertion. The second word
|
|
* must equal the initial insertion of ten seconds on 1 January
|
|
* 1972 plus one second for each succeeding insertion.
|
|
*/
|
|
i = 0;
|
|
while (i < MAX_LEAP) {
|
|
dp = fgets(buf, NTP_MAXSTRLEN - 1, str);
|
|
if (dp == NULL)
|
|
break;
|
|
|
|
if (strlen(buf) < 1)
|
|
continue;
|
|
|
|
if (*buf == '#')
|
|
continue;
|
|
|
|
if (sscanf(buf, "%u %d", &leapsec[i], &offset) != 2)
|
|
continue;
|
|
|
|
if (i != offset - TAI_1972)
|
|
break;
|
|
|
|
i++;
|
|
}
|
|
fclose(str);
|
|
if (dp != NULL) {
|
|
msyslog(LOG_INFO,
|
|
"crypto_tai: leapseconds file %s error %d", cp,
|
|
rval);
|
|
exit (-1);
|
|
}
|
|
|
|
/*
|
|
* The extension field table entries consists of the NTP seconds
|
|
* of leap insertion in network byte order.
|
|
*/
|
|
len = i * sizeof(u_int32);
|
|
tai_leap.vallen = htonl(len);
|
|
ptr = emalloc(len);
|
|
tai_leap.ptr = (u_char *)ptr;
|
|
for (j = 0; j < i; j++)
|
|
*ptr++ = htonl(leapsec[j]);
|
|
crypto_flags |= CRYPTO_FLAG_TAI;
|
|
snprintf(statstr, NTP_MAXSTRLEN, "%s fs %u leap %u len %u", cp, fstamp,
|
|
leapsec[--j], len);
|
|
record_crypto_stats(NULL, statstr);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("crypto_tai: %s\n", statstr);
|
|
#endif
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_setup - load keys, certificate and leapseconds table
|
|
*
|
|
* This routine loads the public/private host key and certificate. If
|
|
* available, it loads the public/private sign key, which defaults to
|
|
* the host key, and leapseconds table. The host key must be RSA, but
|
|
* the sign key can be either RSA or DSA. In either case, the public key
|
|
* on the certificate must agree with the sign key.
|
|
*/
|
|
void
|
|
crypto_setup(void)
|
|
{
|
|
EVP_PKEY *pkey; /* private/public key pair */
|
|
char filename[MAXFILENAME]; /* file name buffer */
|
|
l_fp seed; /* crypto PRNG seed as NTP timestamp */
|
|
tstamp_t fstamp; /* filestamp */
|
|
tstamp_t sstamp; /* sign filestamp */
|
|
u_int len, bytes;
|
|
u_char *ptr;
|
|
|
|
/*
|
|
* Initialize structures.
|
|
*/
|
|
if (!crypto_flags)
|
|
return;
|
|
|
|
gethostname(filename, MAXFILENAME);
|
|
bytes = strlen(filename) + 1;
|
|
sys_hostname = emalloc(bytes);
|
|
memcpy(sys_hostname, filename, bytes);
|
|
if (passwd == NULL)
|
|
passwd = sys_hostname;
|
|
memset(&hostval, 0, sizeof(hostval));
|
|
memset(&pubkey, 0, sizeof(pubkey));
|
|
memset(&tai_leap, 0, sizeof(tai_leap));
|
|
|
|
/*
|
|
* Load required random seed file and seed the random number
|
|
* generator. Be default, it is found in the user home
|
|
* directory. The root home directory may be / or /root,
|
|
* depending on the system. Wiggle the contents a bit and write
|
|
* it back so the sequence does not repeat when we next restart.
|
|
*/
|
|
ERR_load_crypto_strings();
|
|
if (rand_file == NULL) {
|
|
if ((RAND_file_name(filename, MAXFILENAME)) != NULL) {
|
|
rand_file = emalloc(strlen(filename) + 1);
|
|
strcpy(rand_file, filename);
|
|
}
|
|
} else if (*rand_file != '/') {
|
|
snprintf(filename, MAXFILENAME, "%s/%s", keysdir,
|
|
rand_file);
|
|
free(rand_file);
|
|
rand_file = emalloc(strlen(filename) + 1);
|
|
strcpy(rand_file, filename);
|
|
}
|
|
if (rand_file == NULL) {
|
|
msyslog(LOG_ERR,
|
|
"crypto_setup: random seed file not specified");
|
|
exit (-1);
|
|
}
|
|
if ((bytes = RAND_load_file(rand_file, -1)) == 0) {
|
|
msyslog(LOG_ERR,
|
|
"crypto_setup: random seed file %s not found\n",
|
|
rand_file);
|
|
exit (-1);
|
|
}
|
|
get_systime(&seed);
|
|
RAND_seed(&seed, sizeof(l_fp));
|
|
RAND_write_file(rand_file);
|
|
OpenSSL_add_all_algorithms();
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf(
|
|
"crypto_setup: OpenSSL version %lx random seed file %s bytes read %d\n",
|
|
SSLeay(), rand_file, bytes);
|
|
#endif
|
|
|
|
/*
|
|
* Load required host key from file "ntpkey_host_<hostname>". It
|
|
* also becomes the default sign key.
|
|
*/
|
|
if (host_file == NULL) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_host_%s",
|
|
sys_hostname);
|
|
host_file = emalloc(strlen(filename) + 1);
|
|
strcpy(host_file, filename);
|
|
}
|
|
pkey = crypto_key(host_file, &fstamp);
|
|
if (pkey == NULL) {
|
|
msyslog(LOG_ERR,
|
|
"crypto_setup: host key file %s not found or corrupt",
|
|
host_file);
|
|
exit (-1);
|
|
}
|
|
host_pkey = pkey;
|
|
sign_pkey = pkey;
|
|
sstamp = fstamp;
|
|
hostval.fstamp = htonl(fstamp);
|
|
if (host_pkey->type != EVP_PKEY_RSA) {
|
|
msyslog(LOG_ERR,
|
|
"crypto_setup: host key is not RSA key type");
|
|
exit (-1);
|
|
}
|
|
hostval.vallen = htonl(strlen(sys_hostname));
|
|
hostval.ptr = (u_char *)sys_hostname;
|
|
|
|
/*
|
|
* Construct public key extension field for agreement scheme.
|
|
*/
|
|
len = i2d_PublicKey(host_pkey, NULL);
|
|
ptr = emalloc(len);
|
|
pubkey.ptr = ptr;
|
|
i2d_PublicKey(host_pkey, &ptr);
|
|
pubkey.vallen = htonl(len);
|
|
pubkey.fstamp = hostval.fstamp;
|
|
|
|
/*
|
|
* Load optional sign key from file "ntpkey_sign_<hostname>". If
|
|
* loaded, it becomes the sign key.
|
|
*/
|
|
if (sign_file == NULL) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_sign_%s",
|
|
sys_hostname);
|
|
sign_file = emalloc(strlen(filename) + 1);
|
|
strcpy(sign_file, filename);
|
|
}
|
|
pkey = crypto_key(sign_file, &fstamp);
|
|
if (pkey != NULL) {
|
|
sign_pkey = pkey;
|
|
sstamp = fstamp;
|
|
}
|
|
sign_siglen = EVP_PKEY_size(sign_pkey);
|
|
|
|
/*
|
|
* Load optional IFF parameters from file
|
|
* "ntpkey_iff_<hostname>".
|
|
*/
|
|
if (iffpar_file == NULL) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
|
|
sys_hostname);
|
|
iffpar_file = emalloc(strlen(filename) + 1);
|
|
strcpy(iffpar_file, filename);
|
|
}
|
|
iffpar_pkey = crypto_key(iffpar_file, &if_fstamp);
|
|
if (iffpar_pkey != NULL)
|
|
crypto_flags |= CRYPTO_FLAG_IFF;
|
|
|
|
/*
|
|
* Load optional GQ parameters from file "ntpkey_gq_<hostname>".
|
|
*/
|
|
if (gqpar_file == NULL) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
|
|
sys_hostname);
|
|
gqpar_file = emalloc(strlen(filename) + 1);
|
|
strcpy(gqpar_file, filename);
|
|
}
|
|
gqpar_pkey = crypto_key(gqpar_file, &gq_fstamp);
|
|
if (gqpar_pkey != NULL)
|
|
crypto_flags |= CRYPTO_FLAG_GQ;
|
|
|
|
/*
|
|
* Load optional MV parameters from file "ntpkey_mv_<hostname>".
|
|
*/
|
|
if (mvpar_file == NULL) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
|
|
sys_hostname);
|
|
mvpar_file = emalloc(strlen(filename) + 1);
|
|
strcpy(mvpar_file, filename);
|
|
}
|
|
mvpar_pkey = crypto_key(mvpar_file, &mv_fstamp);
|
|
if (mvpar_pkey != NULL)
|
|
crypto_flags |= CRYPTO_FLAG_MV;
|
|
|
|
/*
|
|
* Load required certificate from file "ntpkey_cert_<hostname>".
|
|
*/
|
|
if (cert_file == NULL) {
|
|
snprintf(filename, MAXFILENAME, "ntpkey_cert_%s",
|
|
sys_hostname);
|
|
cert_file = emalloc(strlen(filename) + 1);
|
|
strcpy(cert_file, filename);
|
|
}
|
|
if ((cinfo = crypto_cert(cert_file)) == NULL) {
|
|
msyslog(LOG_ERR,
|
|
"certificate file %s not found or corrupt",
|
|
cert_file);
|
|
exit (-1);
|
|
}
|
|
|
|
/*
|
|
* The subject name must be the same as the host name, unless
|
|
* the certificate is private, in which case it may have come
|
|
* from another host.
|
|
*/
|
|
if (!(cinfo->flags & CERT_PRIV) && strcmp(cinfo->subject,
|
|
sys_hostname) != 0) {
|
|
msyslog(LOG_ERR,
|
|
"crypto_setup: certificate %s not for this host",
|
|
cert_file);
|
|
cert_free(cinfo);
|
|
exit (-1);
|
|
}
|
|
|
|
/*
|
|
* It the certificate is trusted, the subject must be the same
|
|
* as the issuer, in other words it must be self signed.
|
|
*/
|
|
if (cinfo->flags & CERT_TRUST && strcmp(cinfo->subject,
|
|
cinfo->issuer) != 0) {
|
|
if (cert_valid(cinfo, sign_pkey) != XEVNT_OK) {
|
|
msyslog(LOG_ERR,
|
|
"crypto_setup: certificate %s is trusted, but not self signed.",
|
|
cert_file);
|
|
cert_free(cinfo);
|
|
exit (-1);
|
|
}
|
|
}
|
|
sign_digest = cinfo->digest;
|
|
if (cinfo->flags & CERT_PRIV)
|
|
crypto_flags |= CRYPTO_FLAG_PRIV;
|
|
crypto_flags |= cinfo->nid << 16;
|
|
|
|
/*
|
|
* Load optional leapseconds table from file "ntpkey_leap". If
|
|
* the file is missing or defective, the values can later be
|
|
* retrieved from a server.
|
|
*/
|
|
if (leap_file == NULL)
|
|
leap_file = "ntpkey_leap";
|
|
crypto_tai(leap_file);
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf(
|
|
"crypto_setup: flags 0x%x host %s signature %s\n",
|
|
crypto_flags, sys_hostname, OBJ_nid2ln(cinfo->nid));
|
|
#endif
|
|
}
|
|
|
|
|
|
/*
|
|
* crypto_config - configure data from crypto configuration command.
|
|
*/
|
|
void
|
|
crypto_config(
|
|
int item, /* configuration item */
|
|
char *cp /* file name */
|
|
)
|
|
{
|
|
switch (item) {
|
|
|
|
/*
|
|
* Set random seed file name.
|
|
*/
|
|
case CRYPTO_CONF_RAND:
|
|
rand_file = emalloc(strlen(cp) + 1);
|
|
strcpy(rand_file, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set private key password.
|
|
*/
|
|
case CRYPTO_CONF_PW:
|
|
passwd = emalloc(strlen(cp) + 1);
|
|
strcpy(passwd, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set host file name.
|
|
*/
|
|
case CRYPTO_CONF_PRIV:
|
|
host_file = emalloc(strlen(cp) + 1);
|
|
strcpy(host_file, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set sign key file name.
|
|
*/
|
|
case CRYPTO_CONF_SIGN:
|
|
sign_file = emalloc(strlen(cp) + 1);
|
|
strcpy(sign_file, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set iff parameters file name.
|
|
*/
|
|
case CRYPTO_CONF_IFFPAR:
|
|
iffpar_file = emalloc(strlen(cp) + 1);
|
|
strcpy(iffpar_file, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set gq parameters file name.
|
|
*/
|
|
case CRYPTO_CONF_GQPAR:
|
|
gqpar_file = emalloc(strlen(cp) + 1);
|
|
strcpy(gqpar_file, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set mv parameters file name.
|
|
*/
|
|
case CRYPTO_CONF_MVPAR:
|
|
mvpar_file = emalloc(strlen(cp) + 1);
|
|
strcpy(mvpar_file, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set identity scheme.
|
|
*/
|
|
case CRYPTO_CONF_IDENT:
|
|
if (!strcasecmp(cp, "iff"))
|
|
ident_scheme |= CRYPTO_FLAG_IFF;
|
|
else if (!strcasecmp(cp, "gq"))
|
|
ident_scheme |= CRYPTO_FLAG_GQ;
|
|
else if (!strcasecmp(cp, "mv"))
|
|
ident_scheme |= CRYPTO_FLAG_MV;
|
|
break;
|
|
|
|
/*
|
|
* Set certificate file name.
|
|
*/
|
|
case CRYPTO_CONF_CERT:
|
|
cert_file = emalloc(strlen(cp) + 1);
|
|
strcpy(cert_file, cp);
|
|
break;
|
|
|
|
/*
|
|
* Set leapseconds file name.
|
|
*/
|
|
case CRYPTO_CONF_LEAP:
|
|
leap_file = emalloc(strlen(cp) + 1);
|
|
strcpy(leap_file, cp);
|
|
break;
|
|
}
|
|
crypto_flags |= CRYPTO_FLAG_ENAB;
|
|
}
|
|
# else
|
|
int ntp_crypto_bs_pubkey;
|
|
# endif /* OPENSSL */
|