477 lines
12 KiB
C
477 lines
12 KiB
C
/*
|
|
* Copyright (c) 1999-2001 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_verify.c,v 1.5.2.2 2002/02/19 19:23:31 mellon Exp $";
|
|
#endif
|
|
|
|
#define time(x) trace_mr_time (x)
|
|
|
|
/* 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>
|
|
|
|
time_t trace_mr_time (time_t *);
|
|
|
|
/* Private. */
|
|
|
|
#define BOUNDS_CHECK(ptr, count) \
|
|
do { \
|
|
if ((ptr) + (count) > eom) { \
|
|
return (NS_TSIG_ERROR_FORMERR); \
|
|
} \
|
|
} while (0)
|
|
|
|
/* Public. */
|
|
|
|
u_char *
|
|
ns_find_tsig(u_char *msg, u_char *eom) {
|
|
HEADER *hp = (HEADER *)msg;
|
|
int n, type;
|
|
u_char *cp = msg, *start;
|
|
isc_result_t status;
|
|
|
|
if (msg == NULL || eom == NULL || msg > eom)
|
|
return (NULL);
|
|
|
|
if (cp + HFIXEDSZ >= eom)
|
|
return (NULL);
|
|
|
|
if (hp->arcount == 0)
|
|
return (NULL);
|
|
|
|
cp += HFIXEDSZ;
|
|
|
|
status = ns_skiprr(cp, eom, ns_s_qd, ntohs(hp->qdcount), &n);
|
|
if (status != ISC_R_SUCCESS)
|
|
return (NULL);
|
|
cp += n;
|
|
|
|
status = ns_skiprr(cp, eom, ns_s_an, ntohs(hp->ancount), &n);
|
|
if (status != ISC_R_SUCCESS)
|
|
return (NULL);
|
|
cp += n;
|
|
|
|
status = ns_skiprr(cp, eom, ns_s_ns, ntohs(hp->nscount), &n);
|
|
if (status != ISC_R_SUCCESS)
|
|
return (NULL);
|
|
cp += n;
|
|
|
|
status = ns_skiprr(cp, eom, ns_s_ar, ntohs(hp->arcount) - 1, &n);
|
|
if (status != ISC_R_SUCCESS)
|
|
return (NULL);
|
|
cp += n;
|
|
|
|
start = cp;
|
|
n = dn_skipname(cp, eom);
|
|
if (n < 0)
|
|
return (NULL);
|
|
cp += n;
|
|
if (cp + INT16SZ >= eom)
|
|
return (NULL);
|
|
|
|
GETSHORT(type, cp);
|
|
if (type != ns_t_tsig)
|
|
return (NULL);
|
|
return (start);
|
|
}
|
|
|
|
/* ns_verify
|
|
* Parameters:
|
|
* statp res stuff
|
|
* msg received message
|
|
* msglen length of message
|
|
* key tsig key used for verifying.
|
|
* querysig (response), the signature in the query
|
|
* querysiglen (response), the length of the signature in the query
|
|
* sig (query), a buffer to hold the signature
|
|
* siglen (query), input - length of signature buffer
|
|
* output - length of signature
|
|
*
|
|
* Errors:
|
|
* - bad input (-1)
|
|
* - invalid dns message (NS_TSIG_ERROR_FORMERR)
|
|
* - TSIG is not present (NS_TSIG_ERROR_NO_TSIG)
|
|
* - key doesn't match (-ns_r_badkey)
|
|
* - TSIG verification fails with BADKEY (-ns_r_badkey)
|
|
* - TSIG verification fails with BADSIG (-ns_r_badsig)
|
|
* - TSIG verification fails with BADTIME (-ns_r_badtime)
|
|
* - TSIG verification succeeds, error set to BAKEY (ns_r_badkey)
|
|
* - TSIG verification succeeds, error set to BADSIG (ns_r_badsig)
|
|
* - TSIG verification succeeds, error set to BADTIME (ns_r_badtime)
|
|
*/
|
|
isc_result_t
|
|
ns_verify(u_char *msg, unsigned *msglen, void *k,
|
|
const u_char *querysig, unsigned querysiglen,
|
|
u_char *sig, unsigned *siglen, time_t *timesigned, int nostrip)
|
|
{
|
|
HEADER *hp = (HEADER *)msg;
|
|
DST_KEY *key = (DST_KEY *)k;
|
|
u_char *cp = msg, *eom;
|
|
char name[MAXDNAME], alg[MAXDNAME];
|
|
u_char *recstart, *rdatastart;
|
|
u_char *sigstart, *otherstart;
|
|
unsigned n;
|
|
int error;
|
|
u_int16_t type, length;
|
|
u_int16_t fudge, sigfieldlen, id, otherfieldlen;
|
|
|
|
dst_init();
|
|
if (msg == NULL || msglen == NULL || *msglen < 0)
|
|
return ISC_R_INVALIDARG;
|
|
|
|
eom = msg + *msglen;
|
|
|
|
recstart = ns_find_tsig(msg, eom);
|
|
if (recstart == NULL)
|
|
return ISC_R_NO_TSIG;
|
|
|
|
cp = recstart;
|
|
|
|
/* Read the key name. */
|
|
n = dn_expand(msg, eom, cp, name, MAXDNAME);
|
|
if (n < 0)
|
|
return ISC_R_FORMERR;
|
|
cp += n;
|
|
|
|
/* Read the type. */
|
|
BOUNDS_CHECK(cp, 2*INT16SZ + INT32SZ + INT16SZ);
|
|
GETSHORT(type, cp);
|
|
if (type != ns_t_tsig)
|
|
return ISC_R_NO_TSIG;
|
|
|
|
/* Skip the class and TTL, save the length. */
|
|
cp += INT16SZ + INT32SZ;
|
|
GETSHORT(length, cp);
|
|
if (eom - cp != length)
|
|
return ISC_R_FORMERR;
|
|
|
|
/* Read the algorithm name. */
|
|
rdatastart = cp;
|
|
n = dn_expand(msg, eom, cp, alg, MAXDNAME);
|
|
if (n < 0)
|
|
return ISC_R_FORMERR;
|
|
if (ns_samename(alg, NS_TSIG_ALG_HMAC_MD5) != 1)
|
|
return ISC_R_INVALIDKEY;
|
|
cp += n;
|
|
|
|
/* Read the time signed and fudge. */
|
|
BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
|
|
cp += INT16SZ;
|
|
GETLONG((*timesigned), cp);
|
|
GETSHORT(fudge, cp);
|
|
|
|
/* Read the signature. */
|
|
BOUNDS_CHECK(cp, INT16SZ);
|
|
GETSHORT(sigfieldlen, cp);
|
|
BOUNDS_CHECK(cp, sigfieldlen);
|
|
sigstart = cp;
|
|
cp += sigfieldlen;
|
|
|
|
/* Read the original id and error. */
|
|
BOUNDS_CHECK(cp, 2*INT16SZ);
|
|
GETSHORT(id, cp);
|
|
GETSHORT(error, cp);
|
|
|
|
/* Parse the other data. */
|
|
BOUNDS_CHECK(cp, INT16SZ);
|
|
GETSHORT(otherfieldlen, cp);
|
|
BOUNDS_CHECK(cp, otherfieldlen);
|
|
otherstart = cp;
|
|
cp += otherfieldlen;
|
|
|
|
if (cp != eom)
|
|
return ISC_R_FORMERR;
|
|
|
|
/* Verify that the key used is OK. */
|
|
if (key != NULL) {
|
|
if (key->dk_alg != KEY_HMAC_MD5)
|
|
return ISC_R_INVALIDKEY;
|
|
if (error != ns_r_badsig && error != ns_r_badkey) {
|
|
if (ns_samename(key->dk_key_name, name) != 1)
|
|
return ISC_R_INVALIDKEY;
|
|
}
|
|
}
|
|
|
|
hp->arcount = htons(ntohs(hp->arcount) - 1);
|
|
|
|
/*
|
|
* Do the verification.
|
|
*/
|
|
|
|
if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
|
|
void *ctx;
|
|
u_char buf[MAXDNAME];
|
|
|
|
/* Digest the query signature, if this is a response. */
|
|
dst_verify_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
|
|
if (querysiglen > 0 && querysig != NULL) {
|
|
u_int16_t len_n = htons(querysiglen);
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx,
|
|
(u_char *)&len_n, INT16SZ, NULL, 0);
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx,
|
|
querysig, querysiglen, NULL, 0);
|
|
}
|
|
|
|
/* Digest the message. */
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx, msg,
|
|
(unsigned)(recstart - msg), NULL, 0);
|
|
|
|
/* Digest the key name. */
|
|
n = ns_name_ntol(recstart, buf, sizeof(buf));
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
|
|
|
|
/* Digest the class and TTL. */
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx,
|
|
recstart + dn_skipname(recstart, eom) + INT16SZ,
|
|
INT16SZ + INT32SZ, NULL, 0);
|
|
|
|
/* Digest the algorithm. */
|
|
n = ns_name_ntol(rdatastart, buf, sizeof(buf));
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
|
|
|
|
/* Digest the time signed and fudge. */
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx,
|
|
rdatastart + dn_skipname(rdatastart, eom),
|
|
INT16SZ + INT32SZ + INT16SZ, NULL, 0);
|
|
|
|
/* Digest the error and other data. */
|
|
dst_verify_data(SIG_MODE_UPDATE, key, &ctx,
|
|
otherstart - INT16SZ - INT16SZ,
|
|
(unsigned)otherfieldlen + INT16SZ + INT16SZ,
|
|
NULL, 0);
|
|
|
|
n = dst_verify_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
|
|
sigstart, sigfieldlen);
|
|
|
|
if (n < 0)
|
|
return ISC_R_BADSIG;
|
|
|
|
if (sig != NULL && siglen != NULL) {
|
|
if (*siglen < sigfieldlen)
|
|
return ISC_R_NOSPACE;
|
|
memcpy(sig, sigstart, sigfieldlen);
|
|
*siglen = sigfieldlen;
|
|
}
|
|
} else {
|
|
if (sigfieldlen > 0)
|
|
return ISC_R_FORMERR;
|
|
if (sig != NULL && siglen != NULL)
|
|
*siglen = 0;
|
|
}
|
|
|
|
/* Reset the counter, since we still need to check for badtime. */
|
|
hp->arcount = htons(ntohs(hp->arcount) + 1);
|
|
|
|
/* Verify the time. */
|
|
if (abs((*timesigned) - time(NULL)) > fudge)
|
|
return ISC_R_BADTIME;
|
|
|
|
if (nostrip == 0) {
|
|
*msglen = recstart - msg;
|
|
hp->arcount = htons(ntohs(hp->arcount) - 1);
|
|
}
|
|
|
|
if (error != NOERROR)
|
|
return ns_rcode_to_isc (error);
|
|
|
|
return ISC_R_SUCCESS;
|
|
}
|
|
|
|
#if 0
|
|
isc_result_t
|
|
ns_verify_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_verify_tcp(u_char *msg, unsigned *msglen, ns_tcp_tsig_state *state,
|
|
int required)
|
|
{
|
|
HEADER *hp = (HEADER *)msg;
|
|
u_char *recstart, *rdatastart, *sigstart;
|
|
unsigned sigfieldlen, otherfieldlen;
|
|
u_char *cp, *eom = msg + *msglen, *cp2;
|
|
char name[MAXDNAME], alg[MAXDNAME];
|
|
u_char buf[MAXDNAME];
|
|
int n, type, length, fudge, id, error;
|
|
time_t timesigned;
|
|
|
|
if (msg == NULL || msglen == NULL || state == NULL)
|
|
return ISC_R_INVALIDARG;
|
|
|
|
state->counter++;
|
|
if (state->counter == 0)
|
|
return (ns_verify(msg, msglen, state->key,
|
|
state->sig, state->siglen,
|
|
state->sig, &state->siglen, ×igned, 0));
|
|
|
|
if (state->siglen > 0) {
|
|
u_int16_t siglen_n = htons(state->siglen);
|
|
|
|
dst_verify_data(SIG_MODE_INIT, state->key, &state->ctx,
|
|
NULL, 0, NULL, 0);
|
|
dst_verify_data(SIG_MODE_UPDATE, state->key, &state->ctx,
|
|
(u_char *)&siglen_n, INT16SZ, NULL, 0);
|
|
dst_verify_data(SIG_MODE_UPDATE, state->key, &state->ctx,
|
|
state->sig, state->siglen, NULL, 0);
|
|
state->siglen = 0;
|
|
}
|
|
|
|
cp = recstart = ns_find_tsig(msg, eom);
|
|
|
|
if (recstart == NULL) {
|
|
if (required)
|
|
return ISC_R_NO_TSIG;
|
|
dst_verify_data(SIG_MODE_UPDATE, state->key, &state->ctx,
|
|
msg, *msglen, NULL, 0);
|
|
return ISC_R_SUCCESS;
|
|
}
|
|
|
|
hp->arcount = htons(ntohs(hp->arcount) - 1);
|
|
dst_verify_data(SIG_MODE_UPDATE, state->key, &state->ctx,
|
|
msg, (unsigned)(recstart - msg), NULL, 0);
|
|
|
|
/* Read the key name. */
|
|
n = dn_expand(msg, eom, cp, name, MAXDNAME);
|
|
if (n < 0)
|
|
return ISC_R_FORMERR;
|
|
cp += n;
|
|
|
|
/* Read the type. */
|
|
BOUNDS_CHECK(cp, 2*INT16SZ + INT32SZ + INT16SZ);
|
|
GETSHORT(type, cp);
|
|
if (type != ns_t_tsig)
|
|
return ISC_R_NO_TSIG;
|
|
|
|
/* Skip the class and TTL, save the length. */
|
|
cp += INT16SZ + INT32SZ;
|
|
GETSHORT(length, cp);
|
|
if (eom - cp != length)
|
|
return ISC_R_FORMERR;
|
|
|
|
/* Read the algorithm name. */
|
|
rdatastart = cp;
|
|
n = dn_expand(msg, eom, cp, alg, MAXDNAME);
|
|
if (n < 0)
|
|
return ISC_R_FORMERR;
|
|
if (ns_samename(alg, NS_TSIG_ALG_HMAC_MD5) != 1)
|
|
return ISC_R_BADKEY;
|
|
cp += n;
|
|
|
|
/* Verify that the key used is OK. */
|
|
if ((ns_samename(state->key->dk_key_name, name) != 1 ||
|
|
state->key->dk_alg != KEY_HMAC_MD5))
|
|
return ISC_R_BADKEY;
|
|
|
|
/* Read the time signed and fudge. */
|
|
BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
|
|
cp += INT16SZ;
|
|
GETLONG(timesigned, cp);
|
|
GETSHORT(fudge, cp);
|
|
|
|
/* Read the signature. */
|
|
BOUNDS_CHECK(cp, INT16SZ);
|
|
GETSHORT(sigfieldlen, cp);
|
|
BOUNDS_CHECK(cp, sigfieldlen);
|
|
sigstart = cp;
|
|
cp += sigfieldlen;
|
|
|
|
/* Read the original id and error. */
|
|
BOUNDS_CHECK(cp, 2*INT16SZ);
|
|
GETSHORT(id, cp);
|
|
GETSHORT(error, cp);
|
|
|
|
/* Parse the other data. */
|
|
BOUNDS_CHECK(cp, INT16SZ);
|
|
GETSHORT(otherfieldlen, cp);
|
|
BOUNDS_CHECK(cp, otherfieldlen);
|
|
cp += otherfieldlen;
|
|
|
|
if (cp != eom)
|
|
return ISC_R_FORMERR;
|
|
|
|
/*
|
|
* Do the verification.
|
|
*/
|
|
|
|
/* 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_verify_data(SIG_MODE_UPDATE, state->key, &state->ctx,
|
|
buf, (unsigned)(cp2 - buf), NULL, 0);
|
|
|
|
n = dst_verify_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
|
|
sigstart, sigfieldlen);
|
|
if (n < 0)
|
|
return ISC_R_BADSIG;
|
|
|
|
if (sigfieldlen > sizeof(state->sig))
|
|
return ISC_R_BADSIG;
|
|
|
|
if (sigfieldlen > sizeof(state->sig))
|
|
return ISC_R_NOSPACE;
|
|
|
|
memcpy(state->sig, sigstart, sigfieldlen);
|
|
state->siglen = sigfieldlen;
|
|
|
|
/* Verify the time. */
|
|
if (abs(timesigned - time(NULL)) > fudge)
|
|
return ISC_R_BADTIME;
|
|
|
|
*msglen = recstart - msg;
|
|
|
|
if (error != NOERROR)
|
|
return ns_rcode_to_isc (error);
|
|
|
|
return ISC_R_SUCCESS;
|
|
}
|
|
#endif
|