/* 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)
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;
}
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;
}
static int
printZone(ns_type xfr, const char *zone, const struct sockaddr_in *sin,
ns_tsig_key *key)
{
static u_char *answer = NULL;
static int answerLen = 0;
querybuf buf;
int msglen, amtToRead, numRead, result, sockFD, len;
int count, type, rlen, done, n;
int numAnswers, numRecords, soacnt;
u_char *cp, tmp[NS_INT16SZ];
char dname[2][NS_MAXDNAME];
enum { NO_ERRORS, ERR_READING_LEN, ERR_READING_MSG, ERR_PRINTING }
error;
pid_t zpid = -1;
u_char *newmsg;
int newmsglen;
ns_tcp_tsig_state tsig_state;
int tsig_ret, tsig_required, tsig_present;
switch (xfr) {
case ns_t_axfr:
case ns_t_zxfr:
break;
default:
fprintf(stderr, ";; %s - transfer type not supported\n",
p_type(xfr));
return (ERROR);
}
/*
* Create a query packet for the requested zone name.
*/
msglen = res_nmkquery(&res, ns_o_query, zone,
queryClass, ns_t_axfr, NULL,
0, 0, buf.qb2, sizeof buf);
if (msglen < 0) {
if (res.options & RES_DEBUG)
fprintf(stderr, ";; res_nmkquery failed\n");
return (ERROR);
}
/*
* Sign the message if a key was sent
*/
if (key == NULL) {
newmsg = (u_char *)&buf;
newmsglen = msglen;
} else {
DST_KEY *dstkey;
int bufsize, siglen;
u_char sig[64];
int ret;
/* ns_sign() also calls dst_init(), but there is no harm
* doing it twice
*/
dst_init();
bufsize = msglen + 1024;
newmsg = (u_char *) malloc(bufsize);
if (newmsg == NULL) {
errno = ENOMEM;
return (-1);
}
memcpy(newmsg, (u_char *)&buf, msglen);
newmsglen = msglen;
if (strcmp(key->alg, NS_TSIG_ALG_HMAC_MD5) != 0)
dstkey = NULL;
else
dstkey = dst_buffer_to_key(key->name, KEY_HMAC_MD5,
NS_KEY_TYPE_AUTH_ONLY,
NS_KEY_PROT_ANY,
key->data, key->len);
if (dstkey == NULL) {
errno = EINVAL;
if (key)
free(newmsg);
return (-1);
}
siglen = sizeof(sig);
/* newmsglen++; */
ret = ns_sign(newmsg, &newmsglen, bufsize, NOERROR, dstkey, NULL, 0,
sig, &siglen, 0);
if (ret < 0) {
if (key)
free (newmsg);
if (ret == NS_TSIG_ERROR_NO_SPACE)
errno = EMSGSIZE;
else if (ret == -1)
errno = EINVAL;
return (ret);
}
ns_verify_tcp_init(dstkey, sig, siglen, &tsig_state);
}
/*
* Set up a virtual circuit to the server.
*/
if ((sockFD = socket(sin->sin_family, SOCK_STREAM, 0)) < 0) {
int e = errno;
perror(";; socket");
return (e);
}
switch (sin->sin_family) {
case AF_INET:
if (bind(sockFD, (struct sockaddr *)&myaddress,
sizeof myaddress) < 0){
int e = errno;
fprintf(stderr, ";; bind(%s port %u): %s\n",
inet_ntoa(myaddress.sin_addr),
ntohs(myaddress.sin_port),
strerror(e));
(void) close(sockFD);
sockFD = -1;
return (e);
}
if (connect(sockFD, (const struct sockaddr *)sin,
sizeof *sin) < 0) {
int e = errno;
perror(";; connect");
(void) close(sockFD);
sockFD = -1;
return (e);
}
break;
case AF_INET6:
if (bind(sockFD, (struct sockaddr *)&myaddress6,
sizeof myaddress6) < 0){
int e = errno;
char buf[80];
fprintf(stderr, ";; bind(%s port %u): %s\n",
inet_ntop(AF_INET6, &myaddress6.sin6_addr,
buf, sizeof(buf)),
ntohs(myaddress6.sin6_port),
strerror(e));
(void) close(sockFD);
sockFD = -1;
return (e);
}
if (connect(sockFD, (const struct sockaddr *)sin,
sizeof(struct sockaddr_in6)) < 0) {
int e = errno;
perror(";; connect");
(void) close(sockFD);
sockFD = -1;
return (e);
}
break;
}
/*
* Send length & message for zone transfer
*/
ns_put16(newmsglen, tmp);
if (write(sockFD, (char *)tmp, NS_INT16SZ) != NS_INT16SZ ||
write(sockFD, (char *)newmsg, newmsglen) != newmsglen) {
int e = errno;
if (key)
free (newmsg);
perror(";; write");
(void) close(sockFD);
sockFD = -1;
return (e);
} else if (key)
free (newmsg);
/*
* If we're compressing, push a gzip into the pipeline.
*/
if (xfr == ns_t_zxfr) {
enum { rd = 0, wr = 1 };
int z[2];
if (pipe(z) < 0) {
int e = errno;
perror(";; pipe");
(void) close(sockFD);
sockFD = -1;
return (e);
}
zpid = vfork();
if (zpid < 0) {
int e = errno;
perror(";; fork");
(void) close(sockFD);
sockFD = -1;
return (e);
} else if (zpid == 0) {
/* Child. */
(void) close(z[rd]);
(void) dup2(sockFD, STDIN_FILENO);
(void) close(sockFD);
(void) dup2(z[wr], STDOUT_FILENO);
(void) close(z[wr]);
execlp("gzip", "gzip", "-d", "-v", NULL);
perror(";; child: execlp(gunzip)");
_exit(1);
}
/* Parent. */
(void) close(z[wr]);
(void) dup2(z[rd], sockFD);
(void) close(z[rd]);
}
result = 0;
numAnswers = 0;
numRecords = 0;
soacnt = 0;
error = NO_ERRORS;
numRead = 0;
dname[0][0] = '\0';
for (done = 0; !done; (void)NULL) {
/*
* Read the length of the response.
*/
cp = tmp;
amtToRead = INT16SZ;
while (amtToRead > 0 &&
(numRead = read(sockFD, cp, amtToRead)) > 0) {
cp += numRead;
amtToRead -= numRead;
}
if (numRead <= 0) {
error = ERR_READING_LEN;
break;
}
len = ns_get16(tmp);
if (len == 0)
break; /* nothing left to read */
/*
* The server sent too much data to fit the existing buffer --
* allocate a new one.
*/
if (len > answerLen) {
if (answerLen != 0)
free(answer);
answerLen = len;
answer = (u_char *)malloc(answerLen);
}
/*
* Read the response.
*/
amtToRead = len;
cp = answer;
while (amtToRead > 0 &&
(numRead = read(sockFD, cp, amtToRead)) > 0) {
cp += numRead;
amtToRead -= numRead;
}
if (numRead <= 0) {
error = ERR_READING_MSG;
break;
}
result = print_axfr(stdout, answer, len);
if (result != 0) {
error = ERR_PRINTING;
break;
}
numRecords += htons(((HEADER *)answer)->ancount);
numAnswers++;
/* Header. */
cp = answer + HFIXEDSZ;
/* Question. */
for (count = ntohs(((HEADER *)answer)->qdcount);
count > 0;
count--) {
n = dn_skipname(cp, answer + len);
if (n < 0) {
error = ERR_PRINTING;
done++;
break;
}
cp += n + QFIXEDSZ;
if (cp > answer + len) {
error = ERR_PRINTING;
done++;
break;
}
}
/* Answer. */
for (count = ntohs(((HEADER *)answer)->ancount);
count > 0 && !done;
count--) {
n = dn_expand(answer, answer + len, cp,
dname[soacnt], sizeof dname[0]);
if (n < 0) {
error = ERR_PRINTING;
done++;
break;
}
cp += n;
if (cp + 3 * INT16SZ + INT32SZ > answer + len) {
error = ERR_PRINTING;
done++;
break;
}
GETSHORT(type, cp);
cp += INT16SZ;
cp += INT32SZ; /* ttl */
GETSHORT(rlen, cp);
cp += rlen;
if (cp > answer + len) {
error = ERR_PRINTING;
done++;
break;
}
if (type == T_SOA && soacnt++ &&
ns_samename(dname[0], dname[1]) == 1) {
done++;
break;
}
}
/*
* Verify the TSIG
*/
if (key) {
if (ns_find_tsig(answer, answer + len) != NULL)
tsig_present = 1;
else
tsig_present = 0;
if (numAnswers == 1 || soacnt > 1)
tsig_required = 1;
else
tsig_required = 0;
tsig_ret = ns_verify_tcp(answer, &len, &tsig_state,
tsig_required);
if (tsig_ret == 0) {
if (tsig_present)
printf("; TSIG ok\n");
}
else
printf("; TSIG invalid\n");
}
}
printf(";; Received %d answer%s (%d record%s).\n",
numAnswers, (numAnswers != 1) ? "s" : "",
numRecords, (numRecords != 1) ? "s" : "");
(void) close(sockFD);
sockFD = -1;
/*
* If we were uncompressing, reap the uncompressor.
*/
if (xfr == ns_t_zxfr) {
pid_t pid;
int status = 0;
pid = wait(&status);
if (pid < 0) {
int e = errno;
perror(";; wait");
return (e);
}
if (pid != zpid) {
fprintf(stderr, ";; wrong pid (%lu != %lu)\n",
(u_long)pid, (u_long)zpid);
return (ERROR);
}
printf(";; pid %lu: exit %d, signal %d, core %c\n",
(u_long)pid, WEXITSTATUS(status),
WIFSIGNALED(status) ? WTERMSIG(status) : 0,
WCOREDUMP(status) ? 't' : 'f');
}
switch (error) {
case NO_ERRORS:
return (0);
case ERR_READING_LEN:
return (EMSGSIZE);
case ERR_PRINTING:
return (result);
case ERR_READING_MSG:
return (EMSGSIZE);
default:
return (EFAULT);
}
}
