freebsd-skq/contrib/isc-dhcp/minires/ns_sign.c
obrien 47bdc7b536 Import isc-dhcpd-3.0.1rc11.
This fixes a security vulnerability in the bundled resolver library.

Requested by:	scottl(re)
2003-01-16 07:04:57 +00:00

357 lines
9.4 KiB
C

/*
* Copyright (c) 1999-2003 by Internet Software Consortium, Inc.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#ifndef lint
static const char rcsid[] = "$Id: ns_sign.c,v 1.4.2.3 2003/01/14 23:15:06 dhankins Exp $";
#endif
#if defined (TRACING)
#define time(x) trace_mr_time (x)
time_t trace_mr_time (time_t *);
#endif
/* Import. */
#include <sys/types.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include "minires/minires.h"
#include "arpa/nameser.h"
#include <isc-dhcp/dst.h>
#define BOUNDS_CHECK(ptr, count) \
do { \
if ((ptr) + (count) > eob) { \
return ISC_R_NOSPACE; \
} \
} while (0)
/* ns_sign
* Parameters:
* msg message to be sent
* msglen input - length of message
* output - length of signed message
* msgsize length of buffer containing message
* error value to put in the error field
* key tsig key used for signing
* querysig (response), the signature in the query
* querysiglen (response), the length of the signature in the query
* sig a buffer to hold the generated signature
* siglen input - length of signature buffer
* output - length of signature
*
* Errors:
* - bad input data (-1)
* - bad key / sign failed (-BADKEY)
* - not enough space (NS_TSIG_ERROR_NO_SPACE)
*/
isc_result_t
ns_sign(u_char *msg, unsigned *msglen, unsigned msgsize, int error, void *k,
const u_char *querysig, unsigned querysiglen, u_char *sig,
unsigned *siglen, time_t in_timesigned)
{
HEADER *hp = (HEADER *)msg;
DST_KEY *key = (DST_KEY *)k;
u_char *cp = msg + *msglen, *eob = msg + msgsize;
u_char *lenp;
u_char *name, *alg;
unsigned n;
time_t timesigned;
dst_init();
if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
return ISC_R_INVALIDARG;
/* Name. */
if (key != NULL && error != ns_r_badsig && error != ns_r_badkey)
n = dn_comp(key->dk_key_name,
cp, (unsigned)(eob - cp), NULL, NULL);
else
n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
if (n < 0)
return ISC_R_NOSPACE;
name = cp;
cp += n;
/* Type, class, ttl, length (not filled in yet). */
BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
PUTSHORT(ns_t_tsig, cp);
PUTSHORT(ns_c_any, cp);
PUTLONG(0, cp); /* TTL */
lenp = cp;
cp += 2;
/* Alg. */
if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
if (key->dk_alg != KEY_HMAC_MD5)
return ISC_R_BADKEY;
n = dn_comp(NS_TSIG_ALG_HMAC_MD5,
cp, (unsigned)(eob - cp), NULL, NULL);
}
else
n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
if (n < 0)
return ISC_R_NOSPACE;
alg = cp;
cp += n;
/* Time. */
BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
PUTSHORT(0, cp);
timesigned = time(NULL);
if (error != ns_r_badtime)
PUTLONG(timesigned, cp);
else
PUTLONG(in_timesigned, cp);
PUTSHORT(NS_TSIG_FUDGE, cp);
/* Compute the signature. */
if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
void *ctx;
u_char buf[MAXDNAME], *cp2;
unsigned n;
dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
/* Digest the query signature, if this is a response. */
if (querysiglen > 0 && querysig != NULL) {
u_int16_t len_n = htons(querysiglen);
dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
(u_char *)&len_n, INT16SZ, NULL, 0);
dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
querysig, querysiglen, NULL, 0);
}
/* Digest the message. */
dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
NULL, 0);
/* Digest the key name. */
n = ns_name_ntol(name, buf, sizeof(buf));
dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
/* Digest the class and TTL. */
cp2 = buf;
PUTSHORT(ns_c_any, cp2);
PUTLONG(0, cp2);
dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
buf, (unsigned)(cp2-buf), NULL, 0);
/* Digest the algorithm. */
n = ns_name_ntol(alg, buf, sizeof(buf));
dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
/* Digest the time signed, fudge, error, and other data */
cp2 = buf;
PUTSHORT(0, cp2); /* Top 16 bits of time */
if (error != ns_r_badtime)
PUTLONG(timesigned, cp2);
else
PUTLONG(in_timesigned, cp2);
PUTSHORT(NS_TSIG_FUDGE, cp2);
PUTSHORT(error, cp2); /* Error */
if (error != ns_r_badtime)
PUTSHORT(0, cp2); /* Other data length */
else {
PUTSHORT(INT16SZ+INT32SZ, cp2); /* Other data length */
PUTSHORT(0, cp2); /* Top 16 bits of time */
PUTLONG(timesigned, cp2);
}
dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
buf, (unsigned)(cp2-buf), NULL, 0);
n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
sig, *siglen);
if (n < 0)
return ISC_R_BADKEY;
*siglen = n;
} else
*siglen = 0;
/* Add the signature. */
BOUNDS_CHECK(cp, INT16SZ + (*siglen));
PUTSHORT(*siglen, cp);
memcpy(cp, sig, *siglen);
cp += (*siglen);
/* The original message ID & error. */
BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
PUTSHORT(ntohs(hp->id), cp); /* already in network order */
PUTSHORT(error, cp);
/* Other data. */
BOUNDS_CHECK(cp, INT16SZ);
if (error != ns_r_badtime)
PUTSHORT(0, cp); /* Other data length */
else {
PUTSHORT(INT16SZ+INT32SZ, cp); /* Other data length */
BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
PUTSHORT(0, cp); /* Top 16 bits of time */
PUTLONG(timesigned, cp);
}
/* Go back and fill in the length. */
PUTSHORT(cp - lenp - INT16SZ, lenp);
hp->arcount = htons(ntohs(hp->arcount) + 1);
*msglen = (cp - msg);
return ISC_R_SUCCESS;
}
#if 0
isc_result_t
ns_sign_tcp_init(void *k, const u_char *querysig, unsigned querysiglen,
ns_tcp_tsig_state *state)
{
dst_init();
if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
return ISC_R_INVALIDARG;
state->counter = -1;
state->key = k;
if (state->key->dk_alg != KEY_HMAC_MD5)
return ISC_R_BADKEY;
if (querysiglen > sizeof(state->sig))
return ISC_R_NOSPACE;
memcpy(state->sig, querysig, querysiglen);
state->siglen = querysiglen;
return ISC_R_SUCCESS;
}
isc_result_t
ns_sign_tcp(u_char *msg, unsigned *msglen, unsigned msgsize, int error,
ns_tcp_tsig_state *state, int done)
{
u_char *cp, *eob, *lenp;
u_char buf[MAXDNAME], *cp2;
HEADER *hp = (HEADER *)msg;
time_t timesigned;
int n;
if (msg == NULL || msglen == NULL || state == NULL)
return ISC_R_INVALIDARG;
state->counter++;
if (state->counter == 0)
return ns_sign(msg, msglen, msgsize, error, state->key,
state->sig, state->siglen,
state->sig, &state->siglen, 0);
if (state->siglen > 0) {
u_int16_t siglen_n = htons(state->siglen);
dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
NULL, 0, NULL, 0);
dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
(u_char *)&siglen_n, INT16SZ, NULL, 0);
dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
state->sig, state->siglen, NULL, 0);
state->siglen = 0;
}
dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
NULL, 0);
if (done == 0 && (state->counter % 100 != 0))
return ISC_R_SUCCESS;
cp = msg + *msglen;
eob = msg + msgsize;
/* Name. */
n = dn_comp(state->key->dk_key_name,
cp, (unsigned)(eob - cp), NULL, NULL);
if (n < 0)
return ISC_R_NOSPACE;
cp += n;
/* Type, class, ttl, length (not filled in yet). */
BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
PUTSHORT(ns_t_tsig, cp);
PUTSHORT(ns_c_any, cp);
PUTLONG(0, cp); /* TTL */
lenp = cp;
cp += 2;
/* Alg. */
n = dn_comp(NS_TSIG_ALG_HMAC_MD5,
cp, (unsigned)(eob - cp), NULL, NULL);
if (n < 0)
return ISC_R_NOSPACE;
cp += n;
/* Time. */
BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
PUTSHORT(0, cp);
timesigned = time(NULL);
PUTLONG(timesigned, cp);
PUTSHORT(NS_TSIG_FUDGE, cp);
/*
* Compute the signature.
*/
/* Digest the time signed and fudge. */
cp2 = buf;
PUTSHORT(0, cp2); /* Top 16 bits of time */
PUTLONG(timesigned, cp2);
PUTSHORT(NS_TSIG_FUDGE, cp2);
dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
buf, (unsigned)(cp2 - buf), NULL, 0);
n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
state->sig, sizeof(state->sig));
if (n < 0)
return ISC_R_BADKEY;
state->siglen = n;
/* Add the signature. */
BOUNDS_CHECK(cp, INT16SZ + state->siglen);
PUTSHORT(state->siglen, cp);
memcpy(cp, state->sig, state->siglen);
cp += state->siglen;
/* The original message ID & error. */
BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
PUTSHORT(ntohs(hp->id), cp); /* already in network order */
PUTSHORT(error, cp);
/* Other data. */
BOUNDS_CHECK(cp, INT16SZ);
PUTSHORT(0, cp);
/* Go back and fill in the length. */
PUTSHORT(cp - lenp - INT16SZ, lenp);
hp->arcount = htons(ntohs(hp->arcount) + 1);
*msglen = (cp - msg);
return ISC_R_SUCCESS;
}
#endif