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freebsd-skq/sys/netipsec/xform_ah.c
John-Mark Gurney 42e5fcbf2b these are comparing authenticators and need to be constant time... 
This could be a side channel attack...  Now that we have a function
for this, use it...

jmgurney/ipsecgcm:	24d704cc and 7f37a14
2015-07-31 00:31:52 +00:00

1199 lines
29 KiB
C
Raw Blame History

/* $FreeBSD$ */
/* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */
/*-
* The authors of this code are John Ioannidis (ji@tla.org),
* Angelos D. Keromytis (kermit@csd.uch.gr) and
* Niels Provos (provos@physnet.uni-hamburg.de).
*
* The original version of this code was written by John Ioannidis
* for BSD/OS in Athens, Greece, in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis.
*
* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
* and Niels Provos.
*
* Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist.
*
* Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
* Angelos D. Keromytis and Niels Provos.
* Copyright (c) 1999 Niklas Hallqvist.
* Copyright (c) 2001 Angelos D. Keromytis.
*
* Permission to use, copy, and modify this software with or without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
* You may use this code under the GNU public license if you so wish. Please
* contribute changes back to the authors under this freer than GPL license
* so that we may further the use of strong encryption without limitations to
* all.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_ecn.h>
#include <netinet/ip6.h>
#include <netipsec/ipsec.h>
#include <netipsec/ah.h>
#include <netipsec/ah_var.h>
#include <netipsec/xform.h>
#ifdef INET6
#include <netinet6/ip6_var.h>
#include <netipsec/ipsec6.h>
#include <netinet6/ip6_ecn.h>
#endif
#include <netipsec/key.h>
#include <netipsec/key_debug.h>
#include <opencrypto/cryptodev.h>
/*
* Return header size in bytes. The old protocol did not support
* the replay counter; the new protocol always includes the counter.
*/
#define HDRSIZE(sav) \
(((sav)->flags & SADB_X_EXT_OLD) ? \
sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
/*
* Return authenticator size in bytes, based on a field in the
* algorithm descriptor.
*/
#define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \
xform_ah_authsize((sav)->tdb_authalgxform))
VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */
VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */
VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat);
VNET_PCPUSTAT_SYSINIT(ahstat);
#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(ahstat);
#endif /* VIMAGE */
#ifdef INET
SYSCTL_DECL(_net_inet_ah);
SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, "");
SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, "");
SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat,
ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)");
#endif
static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
static int ah_input_cb(struct cryptop*);
static int ah_output_cb(struct cryptop*);
int
xform_ah_authsize(struct auth_hash *esph)
{
int alen;
if (esph == NULL)
return 0;
switch (esph->type) {
case CRYPTO_SHA2_256_HMAC:
case CRYPTO_SHA2_384_HMAC:
case CRYPTO_SHA2_512_HMAC:
alen = esph->hashsize / 2; /* RFC4868 2.3 */
break;
case CRYPTO_AES_128_NIST_GMAC:
case CRYPTO_AES_192_NIST_GMAC:
case CRYPTO_AES_256_NIST_GMAC:
alen = esph->hashsize;
break;
default:
alen = AH_HMAC_HASHLEN;
break;
}
return alen;
}
/*
* NB: this is public for use by the PF_KEY support.
*/
struct auth_hash *
ah_algorithm_lookup(int alg)
{
if (alg > SADB_AALG_MAX)
return NULL;
switch (alg) {
case SADB_X_AALG_NULL:
return &auth_hash_null;
case SADB_AALG_MD5HMAC:
return &auth_hash_hmac_md5;
case SADB_AALG_SHA1HMAC:
return &auth_hash_hmac_sha1;
case SADB_X_AALG_RIPEMD160HMAC:
return &auth_hash_hmac_ripemd_160;
case SADB_X_AALG_MD5:
return &auth_hash_key_md5;
case SADB_X_AALG_SHA:
return &auth_hash_key_sha1;
case SADB_X_AALG_SHA2_256:
return &auth_hash_hmac_sha2_256;
case SADB_X_AALG_SHA2_384:
return &auth_hash_hmac_sha2_384;
case SADB_X_AALG_SHA2_512:
return &auth_hash_hmac_sha2_512;
case SADB_X_AALG_AES128GMAC:
return &auth_hash_nist_gmac_aes_128;
case SADB_X_AALG_AES192GMAC:
return &auth_hash_nist_gmac_aes_192;
case SADB_X_AALG_AES256GMAC:
return &auth_hash_nist_gmac_aes_256;
}
return NULL;
}
size_t
ah_hdrsiz(struct secasvar *sav)
{
size_t size;
if (sav != NULL) {
int authsize;
IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
/*XXX not right for null algorithm--does it matter??*/
authsize = AUTHSIZE(sav);
size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
} else {
/* default guess */
size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
}
return size;
}
/*
* NB: public for use by esp_init.
*/
int
ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
{
struct auth_hash *thash;
int keylen;
thash = ah_algorithm_lookup(sav->alg_auth);
if (thash == NULL) {
DPRINTF(("%s: unsupported authentication algorithm %u\n",
__func__, sav->alg_auth));
return EINVAL;
}
/*
* Verify the replay state block allocation is consistent with
* the protocol type. We check here so we can make assumptions
* later during protocol processing.
*/
/* NB: replay state is setup elsewhere (sigh) */
if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
DPRINTF(("%s: replay state block inconsistency, "
"%s algorithm %s replay state\n", __func__,
(sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
sav->replay == NULL ? "without" : "with"));
return EINVAL;
}
if (sav->key_auth == NULL) {
DPRINTF(("%s: no authentication key for %s algorithm\n",
__func__, thash->name));
return EINVAL;
}
keylen = _KEYLEN(sav->key_auth);
if (keylen != thash->keysize && thash->keysize != 0) {
DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
"keysize %d\n", __func__,
keylen, thash->name, thash->keysize));
return EINVAL;
}
sav->tdb_xform = xsp;
sav->tdb_authalgxform = thash;
/* Initialize crypto session. */
bzero(cria, sizeof (*cria));
cria->cri_alg = sav->tdb_authalgxform->type;
cria->cri_klen = _KEYBITS(sav->key_auth);
cria->cri_key = sav->key_auth->key_data;
cria->cri_mlen = AUTHSIZE(sav);
return 0;
}
/*
* ah_init() is called when an SPI is being set up.
*/
static int
ah_init(struct secasvar *sav, struct xformsw *xsp)
{
struct cryptoini cria;
int error;
error = ah_init0(sav, xsp, &cria);
return error ? error :
crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
}
/*
* Paranoia.
*
* NB: public for use by esp_zeroize (XXX).
*/
int
ah_zeroize(struct secasvar *sav)
{
int err;
if (sav->key_auth)
bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
err = crypto_freesession(sav->tdb_cryptoid);
sav->tdb_cryptoid = 0;
sav->tdb_authalgxform = NULL;
sav->tdb_xform = NULL;
return err;
}
/*
* Massage IPv4/IPv6 headers for AH processing.
*/
static int
ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
{
struct mbuf *m = *m0;
unsigned char *ptr;
int off, count;
#ifdef INET
struct ip *ip;
#endif /* INET */
#ifdef INET6
struct ip6_ext *ip6e;
struct ip6_hdr ip6;
int alloc, len, ad;
#endif /* INET6 */
switch (proto) {
#ifdef INET
case AF_INET:
/*
* This is the least painful way of dealing with IPv4 header
* and option processing -- just make sure they're in
* contiguous memory.
*/
*m0 = m = m_pullup(m, skip);
if (m == NULL) {
DPRINTF(("%s: m_pullup failed\n", __func__));
return ENOBUFS;
}
/* Fix the IP header */
ip = mtod(m, struct ip *);
if (V_ah_cleartos)
ip->ip_tos = 0;
ip->ip_ttl = 0;
ip->ip_sum = 0;
if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
ip->ip_off &= htons(IP_DF);
else
ip->ip_off = htons(0);
ptr = mtod(m, unsigned char *) + sizeof(struct ip);
/* IPv4 option processing */
for (off = sizeof(struct ip); off < skip;) {
if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
off + 1 < skip)
;
else {
DPRINTF(("%s: illegal IPv4 option length for "
"option %d\n", __func__, ptr[off]));
m_freem(m);
return EINVAL;
}
switch (ptr[off]) {
case IPOPT_EOL:
off = skip; /* End the loop. */
break;
case IPOPT_NOP:
off++;
break;
case IPOPT_SECURITY: /* 0x82 */
case 0x85: /* Extended security. */
case 0x86: /* Commercial security. */
case 0x94: /* Router alert */
case 0x95: /* RFC1770 */
/* Sanity check for option length. */
if (ptr[off + 1] < 2) {
DPRINTF(("%s: illegal IPv4 option "
"length for option %d\n",
__func__, ptr[off]));
m_freem(m);
return EINVAL;
}
off += ptr[off + 1];
break;
case IPOPT_LSRR:
case IPOPT_SSRR:
/* Sanity check for option length. */
if (ptr[off + 1] < 2) {
DPRINTF(("%s: illegal IPv4 option "
"length for option %d\n",
__func__, ptr[off]));
m_freem(m);
return EINVAL;
}
/*
* On output, if we have either of the
* source routing options, we should
* swap the destination address of the
* IP header with the last address
* specified in the option, as that is
* what the destination's IP header
* will look like.
*/
if (out)
bcopy(ptr + off + ptr[off + 1] -
sizeof(struct in_addr),
&(ip->ip_dst), sizeof(struct in_addr));
/* Fall through */
default:
/* Sanity check for option length. */
if (ptr[off + 1] < 2) {
DPRINTF(("%s: illegal IPv4 option "
"length for option %d\n",
__func__, ptr[off]));
m_freem(m);
return EINVAL;
}
/* Zeroize all other options. */
count = ptr[off + 1];
bcopy(ipseczeroes, ptr, count);
off += count;
break;
}
/* Sanity check. */
if (off > skip) {
DPRINTF(("%s: malformed IPv4 options header\n",
__func__));
m_freem(m);
return EINVAL;
}
}
break;
#endif /* INET */
#ifdef INET6
case AF_INET6: /* Ugly... */
/* Copy and "cook" the IPv6 header. */
m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
/* We don't do IPv6 Jumbograms. */
if (ip6.ip6_plen == 0) {
DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
m_freem(m);
return EMSGSIZE;
}
ip6.ip6_flow = 0;
ip6.ip6_hlim = 0;
ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
ip6.ip6_vfc |= IPV6_VERSION;
/* Scoped address handling. */
if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
ip6.ip6_src.s6_addr16[1] = 0;
if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
ip6.ip6_dst.s6_addr16[1] = 0;
/* Done with IPv6 header. */
m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
/* Let's deal with the remaining headers (if any). */
if (skip - sizeof(struct ip6_hdr) > 0) {
if (m->m_len <= skip) {
ptr = (unsigned char *) malloc(
skip - sizeof(struct ip6_hdr),
M_XDATA, M_NOWAIT);
if (ptr == NULL) {
DPRINTF(("%s: failed to allocate memory"
"for IPv6 headers\n",__func__));
m_freem(m);
return ENOBUFS;
}
/*
* Copy all the protocol headers after
* the IPv6 header.
*/
m_copydata(m, sizeof(struct ip6_hdr),
skip - sizeof(struct ip6_hdr), ptr);
alloc = 1;
} else {
/* No need to allocate memory. */
ptr = mtod(m, unsigned char *) +
sizeof(struct ip6_hdr);
alloc = 0;
}
} else
break;
off = ip6.ip6_nxt & 0xff; /* Next header type. */
for (len = 0; len < skip - sizeof(struct ip6_hdr);)
switch (off) {
case IPPROTO_HOPOPTS:
case IPPROTO_DSTOPTS:
ip6e = (struct ip6_ext *) (ptr + len);
/*
* Process the mutable/immutable
* options -- borrows heavily from the
* KAME code.
*/
for (count = len + sizeof(struct ip6_ext);
count < len + ((ip6e->ip6e_len + 1) << 3);) {
if (ptr[count] == IP6OPT_PAD1) {
count++;
continue; /* Skip padding. */
}
/* Sanity check. */
if (count > len +
((ip6e->ip6e_len + 1) << 3)) {
m_freem(m);
/* Free, if we allocated. */
if (alloc)
free(ptr, M_XDATA);
return EINVAL;
}
ad = ptr[count + 1];
/* If mutable option, zeroize. */
if (ptr[count] & IP6OPT_MUTABLE)
bcopy(ipseczeroes, ptr + count,
ptr[count + 1]);
count += ad;
/* Sanity check. */
if (count >
skip - sizeof(struct ip6_hdr)) {
m_freem(m);
/* Free, if we allocated. */
if (alloc)
free(ptr, M_XDATA);
return EINVAL;
}
}
/* Advance. */
len += ((ip6e->ip6e_len + 1) << 3);
off = ip6e->ip6e_nxt;
break;
case IPPROTO_ROUTING:
/*
* Always include routing headers in
* computation.
*/
ip6e = (struct ip6_ext *) (ptr + len);
len += ((ip6e->ip6e_len + 1) << 3);
off = ip6e->ip6e_nxt;
break;
default:
DPRINTF(("%s: unexpected IPv6 header type %d",
__func__, off));
if (alloc)
free(ptr, M_XDATA);
m_freem(m);
return EINVAL;
}
/* Copyback and free, if we allocated. */
if (alloc) {
m_copyback(m, sizeof(struct ip6_hdr),
skip - sizeof(struct ip6_hdr), ptr);
free(ptr, M_XDATA);
}
break;
#endif /* INET6 */
}
return 0;
}
/*
* ah_input() gets called to verify that an input packet
* passes authentication.
*/
static int
ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
char buf[128];
struct auth_hash *ahx;
struct tdb_crypto *tc;
struct newah *ah;
int hl, rplen, authsize, error;
struct cryptodesc *crda;
struct cryptop *crp;
IPSEC_ASSERT(sav != NULL, ("null SA"));
IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
("null authentication xform"));
/* Figure out header size. */
rplen = HDRSIZE(sav);
/* XXX don't pullup, just copy header */
IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
if (ah == NULL) {
DPRINTF(("ah_input: cannot pullup header\n"));
AHSTAT_INC(ahs_hdrops); /*XXX*/
m_freem(m);
return ENOBUFS;
}
/* Check replay window, if applicable. */
if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
AHSTAT_INC(ahs_replay);
DPRINTF(("%s: packet replay failure: %s\n", __func__,
ipsec_logsastr(sav, buf, sizeof(buf))));
m_freem(m);
return ENOBUFS;
}
/* Verify AH header length. */
hl = ah->ah_len * sizeof (u_int32_t);
ahx = sav->tdb_authalgxform;
authsize = AUTHSIZE(sav);
if (hl != authsize + rplen - sizeof (struct ah)) {
DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
" for packet in SA %s/%08lx\n", __func__, hl,
(u_long) (authsize + rplen - sizeof (struct ah)),
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_badauthl);
m_freem(m);
return EACCES;
}
AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
/* Get crypto descriptors. */
crp = crypto_getreq(1);
if (crp == NULL) {
DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
AHSTAT_INC(ahs_crypto);
m_freem(m);
return ENOBUFS;
}
crda = crp->crp_desc;
IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
crda->crd_skip = 0;
crda->crd_len = m->m_pkthdr.len;
crda->crd_inject = skip + rplen;
/* Authentication operation. */
crda->crd_alg = ahx->type;
crda->crd_klen = _KEYBITS(sav->key_auth);
crda->crd_key = sav->key_auth->key_data;
/* Allocate IPsec-specific opaque crypto info. */
tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
skip + rplen + authsize, M_XDATA, M_NOWAIT | M_ZERO);
if (tc == NULL) {
DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
AHSTAT_INC(ahs_crypto);
crypto_freereq(crp);
m_freem(m);
return ENOBUFS;
}
/*
* Save the authenticator, the skipped portion of the packet,
* and the AH header.
*/
m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
/* Zeroize the authenticator on the packet. */
m_copyback(m, skip + rplen, authsize, ipseczeroes);
/* "Massage" the packet headers for crypto processing. */
error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
skip, ahx->type, 0);
if (error != 0) {
/* NB: mbuf is free'd by ah_massage_headers */
AHSTAT_INC(ahs_hdrops);
free(tc, M_XDATA);
crypto_freereq(crp);
return (error);
}
/* Crypto operation descriptor. */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = ah_input_cb;
crp->crp_sid = sav->tdb_cryptoid;
crp->crp_opaque = (caddr_t) tc;
/* These are passed as-is to the callback. */
tc->tc_spi = sav->spi;
tc->tc_dst = sav->sah->saidx.dst;
tc->tc_proto = sav->sah->saidx.proto;
tc->tc_nxt = ah->ah_nxt;
tc->tc_protoff = protoff;
tc->tc_skip = skip;
KEY_ADDREFSA(sav);
tc->tc_sav = sav;
return (crypto_dispatch(crp));
}
/*
* AH input callback from the crypto driver.
*/
static int
ah_input_cb(struct cryptop *crp)
{
char buf[INET6_ADDRSTRLEN];
int rplen, error, skip, protoff;
unsigned char calc[AH_ALEN_MAX];
struct mbuf *m;
struct cryptodesc *crd;
struct auth_hash *ahx;
struct tdb_crypto *tc;
struct secasvar *sav;
struct secasindex *saidx;
u_int8_t nxt;
caddr_t ptr;
int authsize;
crd = crp->crp_desc;
tc = (struct tdb_crypto *) crp->crp_opaque;
IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
skip = tc->tc_skip;
nxt = tc->tc_nxt;
protoff = tc->tc_protoff;
m = (struct mbuf *) crp->crp_buf;
sav = tc->tc_sav;
IPSEC_ASSERT(sav != NULL, ("null SA!"));
saidx = &sav->sah->saidx;
IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
saidx->dst.sa.sa_family == AF_INET6,
("unexpected protocol family %u", saidx->dst.sa.sa_family));
ahx = (struct auth_hash *) sav->tdb_authalgxform;
/* Check for crypto errors. */
if (crp->crp_etype) {
if (sav->tdb_cryptoid != 0)
sav->tdb_cryptoid = crp->crp_sid;
if (crp->crp_etype == EAGAIN)
return (crypto_dispatch(crp));
AHSTAT_INC(ahs_noxform);
DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
error = crp->crp_etype;
goto bad;
} else {
AHSTAT_INC(ahs_hist[sav->alg_auth]);
crypto_freereq(crp); /* No longer needed. */
crp = NULL;
}
/* Shouldn't happen... */
if (m == NULL) {
AHSTAT_INC(ahs_crypto);
DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
error = EINVAL;
goto bad;
}
/* Figure out header size. */
rplen = HDRSIZE(sav);
authsize = AUTHSIZE(sav);
/* Copy authenticator off the packet. */
m_copydata(m, skip + rplen, authsize, calc);
/* Verify authenticator. */
ptr = (caddr_t) (tc + 1);
if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
DPRINTF(("%s: authentication hash mismatch for packet "
"in SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_badauth);
error = EACCES;
goto bad;
}
/* Fix the Next Protocol field. */
((u_int8_t *) ptr)[protoff] = nxt;
/* Copyback the saved (uncooked) network headers. */
m_copyback(m, 0, skip, ptr);
free(tc, M_XDATA), tc = NULL; /* No longer needed */
/*
* Header is now authenticated.
*/
m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
/*
* Update replay sequence number, if appropriate.
*/
if (sav->replay) {
u_int32_t seq;
m_copydata(m, skip + offsetof(struct newah, ah_seq),
sizeof (seq), (caddr_t) &seq);
if (ipsec_updatereplay(ntohl(seq), sav)) {
AHSTAT_INC(ahs_replay);
error = ENOBUFS; /*XXX as above*/
goto bad;
}
}
/*
* Remove the AH header and authenticator from the mbuf.
*/
error = m_striphdr(m, skip, rplen + authsize);
if (error) {
DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_hdrops);
goto bad;
}
switch (saidx->dst.sa.sa_family) {
#ifdef INET6
case AF_INET6:
error = ipsec6_common_input_cb(m, sav, skip, protoff);
break;
#endif
#ifdef INET
case AF_INET:
error = ipsec4_common_input_cb(m, sav, skip, protoff);
break;
#endif
default:
panic("%s: Unexpected address family: %d saidx=%p", __func__,
saidx->dst.sa.sa_family, saidx);
}
KEY_FREESAV(&sav);
return error;
bad:
if (sav)
KEY_FREESAV(&sav);
if (m != NULL)
m_freem(m);
if (tc != NULL)
free(tc, M_XDATA);
if (crp != NULL)
crypto_freereq(crp);
return error;
}
/*
* AH output routine, called by ipsec[46]_process_packet().
*/
static int
ah_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp,
int skip, int protoff)
{
char buf[INET6_ADDRSTRLEN];
struct secasvar *sav;
struct auth_hash *ahx;
struct cryptodesc *crda;
struct tdb_crypto *tc;
struct mbuf *mi;
struct cryptop *crp;
u_int16_t iplen;
int error, rplen, authsize, maxpacketsize, roff;
u_int8_t prot;
struct newah *ah;
sav = isr->sav;
IPSEC_ASSERT(sav != NULL, ("null SA"));
ahx = sav->tdb_authalgxform;
IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
AHSTAT_INC(ahs_output);
/* Figure out header size. */
rplen = HDRSIZE(sav);
/* Check for maximum packet size violations. */
switch (sav->sah->saidx.dst.sa.sa_family) {
#ifdef INET
case AF_INET:
maxpacketsize = IP_MAXPACKET;
break;
#endif /* INET */
#ifdef INET6
case AF_INET6:
maxpacketsize = IPV6_MAXPACKET;
break;
#endif /* INET6 */
default:
DPRINTF(("%s: unknown/unsupported protocol family %u, "
"SA %s/%08lx\n", __func__,
sav->sah->saidx.dst.sa.sa_family,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_nopf);
error = EPFNOSUPPORT;
goto bad;
}
authsize = AUTHSIZE(sav);
if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
DPRINTF(("%s: packet in SA %s/%08lx got too big "
"(len %u, max len %u)\n", __func__,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi),
rplen + authsize + m->m_pkthdr.len, maxpacketsize));
AHSTAT_INC(ahs_toobig);
error = EMSGSIZE;
goto bad;
}
/* Update the counters. */
AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip);
m = m_unshare(m, M_NOWAIT);
if (m == NULL) {
DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_hdrops);
error = ENOBUFS;
goto bad;
}
/* Inject AH header. */
mi = m_makespace(m, skip, rplen + authsize, &roff);
if (mi == NULL) {
DPRINTF(("%s: failed to inject %u byte AH header for SA "
"%s/%08lx\n", __func__,
rplen + authsize,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
error = ENOBUFS;
goto bad;
}
/*
* The AH header is guaranteed by m_makespace() to be in
* contiguous memory, at roff bytes offset into the returned mbuf.
*/
ah = (struct newah *)(mtod(mi, caddr_t) + roff);
/* Initialize the AH header. */
m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
ah->ah_reserve = 0;
ah->ah_spi = sav->spi;
/* Zeroize authenticator. */
m_copyback(m, skip + rplen, authsize, ipseczeroes);
/* Insert packet replay counter, as requested. */
if (sav->replay) {
if (sav->replay->count == ~0 &&
(sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
__func__, ipsec_address(&sav->sah->saidx.dst, buf,
sizeof(buf)), (u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_wrap);
error = EINVAL;
goto bad;
}
#ifdef REGRESSION
/* Emulate replay attack when ipsec_replay is TRUE. */
if (!V_ipsec_replay)
#endif
sav->replay->count++;
ah->ah_seq = htonl(sav->replay->count);
}
/* Get crypto descriptors. */
crp = crypto_getreq(1);
if (crp == NULL) {
DPRINTF(("%s: failed to acquire crypto descriptors\n",
__func__));
AHSTAT_INC(ahs_crypto);
error = ENOBUFS;
goto bad;
}
crda = crp->crp_desc;
crda->crd_skip = 0;
crda->crd_inject = skip + rplen;
crda->crd_len = m->m_pkthdr.len;
/* Authentication operation. */
crda->crd_alg = ahx->type;
crda->crd_key = sav->key_auth->key_data;
crda->crd_klen = _KEYBITS(sav->key_auth);
/* Allocate IPsec-specific opaque crypto info. */
tc = (struct tdb_crypto *) malloc(
sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
if (tc == NULL) {
crypto_freereq(crp);
DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
AHSTAT_INC(ahs_crypto);
error = ENOBUFS;
goto bad;
}
/* Save the skipped portion of the packet. */
m_copydata(m, 0, skip, (caddr_t) (tc + 1));
/*
* Fix IP header length on the header used for
* authentication. We don't need to fix the original
* header length as it will be fixed by our caller.
*/
switch (sav->sah->saidx.dst.sa.sa_family) {
#ifdef INET
case AF_INET:
bcopy(((caddr_t)(tc + 1)) +
offsetof(struct ip, ip_len),
(caddr_t) &iplen, sizeof(u_int16_t));
iplen = htons(ntohs(iplen) + rplen + authsize);
m_copyback(m, offsetof(struct ip, ip_len),
sizeof(u_int16_t), (caddr_t) &iplen);
break;
#endif /* INET */
#ifdef INET6
case AF_INET6:
bcopy(((caddr_t)(tc + 1)) +
offsetof(struct ip6_hdr, ip6_plen),
(caddr_t) &iplen, sizeof(u_int16_t));
iplen = htons(ntohs(iplen) + rplen + authsize);
m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
sizeof(u_int16_t), (caddr_t) &iplen);
break;
#endif /* INET6 */
}
/* Fix the Next Header field in saved header. */
((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
/* Update the Next Protocol field in the IP header. */
prot = IPPROTO_AH;
m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
/* "Massage" the packet headers for crypto processing. */
error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
skip, ahx->type, 1);
if (error != 0) {
m = NULL; /* mbuf was free'd by ah_massage_headers. */
free(tc, M_XDATA);
crypto_freereq(crp);
goto bad;
}
/* Crypto operation descriptor. */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = ah_output_cb;
crp->crp_sid = sav->tdb_cryptoid;
crp->crp_opaque = (caddr_t) tc;
/* These are passed as-is to the callback. */
tc->tc_isr = isr;
KEY_ADDREFSA(sav);
tc->tc_sav = sav;
tc->tc_spi = sav->spi;
tc->tc_dst = sav->sah->saidx.dst;
tc->tc_proto = sav->sah->saidx.proto;
tc->tc_skip = skip;
tc->tc_protoff = protoff;
return crypto_dispatch(crp);
bad:
if (m)
m_freem(m);
return (error);
}
/*
* AH output callback from the crypto driver.
*/
static int
ah_output_cb(struct cryptop *crp)
{
int skip, protoff, error;
struct tdb_crypto *tc;
struct ipsecrequest *isr;
struct secasvar *sav;
struct mbuf *m;
caddr_t ptr;
tc = (struct tdb_crypto *) crp->crp_opaque;
IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
skip = tc->tc_skip;
protoff = tc->tc_protoff;
ptr = (caddr_t) (tc + 1);
m = (struct mbuf *) crp->crp_buf;
isr = tc->tc_isr;
IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp"));
IPSECREQUEST_LOCK(isr);
sav = tc->tc_sav;
/* With the isr lock released SA pointer can be updated. */
if (sav != isr->sav) {
AHSTAT_INC(ahs_notdb);
DPRINTF(("%s: SA expired while in crypto\n", __func__));
error = ENOBUFS; /*XXX*/
goto bad;
}
/* Check for crypto errors. */
if (crp->crp_etype) {
if (sav->tdb_cryptoid != 0)
sav->tdb_cryptoid = crp->crp_sid;
if (crp->crp_etype == EAGAIN) {
IPSECREQUEST_UNLOCK(isr);
return (crypto_dispatch(crp));
}
AHSTAT_INC(ahs_noxform);
DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
error = crp->crp_etype;
goto bad;
}
/* Shouldn't happen... */
if (m == NULL) {
AHSTAT_INC(ahs_crypto);
DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
error = EINVAL;
goto bad;
}
AHSTAT_INC(ahs_hist[sav->alg_auth]);
/*
* Copy original headers (with the new protocol number) back
* in place.
*/
m_copyback(m, 0, skip, ptr);
/* No longer needed. */
free(tc, M_XDATA);
crypto_freereq(crp);
#ifdef REGRESSION
/* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
if (V_ipsec_integrity) {
int alen;
/*
* Corrupt HMAC if we want to test integrity verification of
* the other side.
*/
alen = AUTHSIZE(sav);
m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
}
#endif
/* NB: m is reclaimed by ipsec_process_done. */
error = ipsec_process_done(m, isr);
KEY_FREESAV(&sav);
IPSECREQUEST_UNLOCK(isr);
KEY_FREESP(&isr->sp);
return (error);
bad:
if (sav)
KEY_FREESAV(&sav);
IPSECREQUEST_UNLOCK(isr);
KEY_FREESP(&isr->sp);
if (m)
m_freem(m);
free(tc, M_XDATA);
crypto_freereq(crp);
return (error);
}
static struct xformsw ah_xformsw = {
XF_AH, XFT_AUTH, "IPsec AH",
ah_init, ah_zeroize, ah_input, ah_output,
};
static void
ah_attach(void)
{
xform_register(&ah_xformsw);
}
SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
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