diff options
Diffstat (limited to 'lib/dns/tsig.c')
| -rw-r--r-- | lib/dns/tsig.c | 1902 |
1 files changed, 1902 insertions, 0 deletions
diff --git a/lib/dns/tsig.c b/lib/dns/tsig.c new file mode 100644 index 0000000..e102d09 --- /dev/null +++ b/lib/dns/tsig.c @@ -0,0 +1,1902 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, you can obtain one at https://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +/*! \file */ + +#include <inttypes.h> +#include <stdbool.h> +#include <stdlib.h> + +#include <isc/buffer.h> +#include <isc/mem.h> +#include <isc/print.h> +#include <isc/refcount.h> +#include <isc/serial.h> +#include <isc/string.h> /* Required for HP/UX (and others?) */ +#include <isc/time.h> +#include <isc/util.h> + +#include <pk11/site.h> + +#include <dns/fixedname.h> +#include <dns/keyvalues.h> +#include <dns/log.h> +#include <dns/message.h> +#include <dns/rbt.h> +#include <dns/rdata.h> +#include <dns/rdatalist.h> +#include <dns/rdataset.h> +#include <dns/rdatastruct.h> +#include <dns/result.h> +#include <dns/tsig.h> + +#include <dst/result.h> + +#include "tsig_p.h" + +#define TSIG_MAGIC ISC_MAGIC('T', 'S', 'I', 'G') +#define VALID_TSIG_KEY(x) ISC_MAGIC_VALID(x, TSIG_MAGIC) + +#ifndef DNS_TSIG_MAXGENERATEDKEYS +#define DNS_TSIG_MAXGENERATEDKEYS 4096 +#endif /* ifndef DNS_TSIG_MAXGENERATEDKEYS */ + +#define is_response(msg) ((msg->flags & DNS_MESSAGEFLAG_QR) != 0) + +#define BADTIMELEN 6 + +static unsigned char hmacmd5_ndata[] = "\010hmac-md5\007sig-alg\003reg\003int"; +static unsigned char hmacmd5_offsets[] = { 0, 9, 17, 21, 25 }; + +static dns_name_t const hmacmd5 = DNS_NAME_INITABSOLUTE(hmacmd5_ndata, + hmacmd5_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_hmacmd5_name = &hmacmd5; + +static unsigned char gsstsig_ndata[] = "\010gss-tsig"; +static unsigned char gsstsig_offsets[] = { 0, 9 }; +static dns_name_t const gsstsig = DNS_NAME_INITABSOLUTE(gsstsig_ndata, + gsstsig_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_gssapi_name = &gsstsig; + +/* + * Since Microsoft doesn't follow its own standard, we will use this + * alternate name as a second guess. + */ +static unsigned char gsstsigms_ndata[] = "\003gss\011microsoft\003com"; +static unsigned char gsstsigms_offsets[] = { 0, 4, 14, 18 }; +static dns_name_t const gsstsigms = DNS_NAME_INITABSOLUTE(gsstsigms_ndata, + gsstsigms_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_gssapims_name = &gsstsigms; + +static unsigned char hmacsha1_ndata[] = "\011hmac-sha1"; +static unsigned char hmacsha1_offsets[] = { 0, 10 }; +static dns_name_t const hmacsha1 = DNS_NAME_INITABSOLUTE(hmacsha1_ndata, + hmacsha1_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_hmacsha1_name = &hmacsha1; + +static unsigned char hmacsha224_ndata[] = "\013hmac-sha224"; +static unsigned char hmacsha224_offsets[] = { 0, 12 }; +static dns_name_t const hmacsha224 = DNS_NAME_INITABSOLUTE(hmacsha224_ndata, + hmacsha224_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_hmacsha224_name = &hmacsha224; + +static unsigned char hmacsha256_ndata[] = "\013hmac-sha256"; +static unsigned char hmacsha256_offsets[] = { 0, 12 }; +static dns_name_t const hmacsha256 = DNS_NAME_INITABSOLUTE(hmacsha256_ndata, + hmacsha256_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_hmacsha256_name = &hmacsha256; + +static unsigned char hmacsha384_ndata[] = "\013hmac-sha384"; +static unsigned char hmacsha384_offsets[] = { 0, 12 }; +static dns_name_t const hmacsha384 = DNS_NAME_INITABSOLUTE(hmacsha384_ndata, + hmacsha384_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_hmacsha384_name = &hmacsha384; + +static unsigned char hmacsha512_ndata[] = "\013hmac-sha512"; +static unsigned char hmacsha512_offsets[] = { 0, 12 }; +static dns_name_t const hmacsha512 = DNS_NAME_INITABSOLUTE(hmacsha512_ndata, + hmacsha512_offsets); +LIBDNS_EXTERNAL_DATA const dns_name_t *dns_tsig_hmacsha512_name = &hmacsha512; + +static const struct { + const dns_name_t *name; + unsigned int dstalg; +} known_algs[] = { { &hmacmd5, DST_ALG_HMACMD5 }, + { &gsstsig, DST_ALG_GSSAPI }, + { &gsstsigms, DST_ALG_GSSAPI }, + { &hmacsha1, DST_ALG_HMACSHA1 }, + { &hmacsha224, DST_ALG_HMACSHA224 }, + { &hmacsha256, DST_ALG_HMACSHA256 }, + { &hmacsha384, DST_ALG_HMACSHA384 }, + { &hmacsha512, DST_ALG_HMACSHA512 } }; + +static isc_result_t +tsig_verify_tcp(isc_buffer_t *source, dns_message_t *msg); + +static void +tsig_log(dns_tsigkey_t *key, int level, const char *fmt, ...) + ISC_FORMAT_PRINTF(3, 4); + +static void +cleanup_ring(dns_tsig_keyring_t *ring); +static void +tsigkey_free(dns_tsigkey_t *key); + +bool +dns__tsig_algvalid(unsigned int alg) { + return (alg == DST_ALG_HMACMD5 || alg == DST_ALG_HMACSHA1 || + alg == DST_ALG_HMACSHA224 || alg == DST_ALG_HMACSHA256 || + alg == DST_ALG_HMACSHA384 || alg == DST_ALG_HMACSHA512); +} + +static void +tsig_log(dns_tsigkey_t *key, int level, const char *fmt, ...) { + va_list ap; + char message[4096]; + char namestr[DNS_NAME_FORMATSIZE]; + char creatorstr[DNS_NAME_FORMATSIZE]; + + if (!isc_log_wouldlog(dns_lctx, level)) { + return; + } + if (key != NULL) { + dns_name_format(&key->name, namestr, sizeof(namestr)); + } else { + strlcpy(namestr, "<null>", sizeof(namestr)); + } + + if (key != NULL && key->generated && key->creator) { + dns_name_format(key->creator, creatorstr, sizeof(creatorstr)); + } else { + strlcpy(creatorstr, "<null>", sizeof(creatorstr)); + } + + va_start(ap, fmt); + vsnprintf(message, sizeof(message), fmt, ap); + va_end(ap); + if (key != NULL && key->generated) { + isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC, + DNS_LOGMODULE_TSIG, level, + "tsig key '%s' (%s): %s", namestr, creatorstr, + message); + } else { + isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC, + DNS_LOGMODULE_TSIG, level, "tsig key '%s': %s", + namestr, message); + } +} + +static void +remove_fromring(dns_tsigkey_t *tkey) { + if (tkey->generated) { + ISC_LIST_UNLINK(tkey->ring->lru, tkey, link); + tkey->ring->generated--; + } + (void)dns_rbt_deletename(tkey->ring->keys, &tkey->name, false); +} + +static void +adjust_lru(dns_tsigkey_t *tkey) { + if (tkey->generated) { + RWLOCK(&tkey->ring->lock, isc_rwlocktype_write); + /* + * We may have been removed from the LRU list between + * removing the read lock and acquiring the write lock. + */ + if (ISC_LINK_LINKED(tkey, link) && tkey->ring->lru.tail != tkey) + { + ISC_LIST_UNLINK(tkey->ring->lru, tkey, link); + ISC_LIST_APPEND(tkey->ring->lru, tkey, link); + } + RWUNLOCK(&tkey->ring->lock, isc_rwlocktype_write); + } +} + +/* + * A supplemental routine just to add a key to ring. Note that reference + * counter should be counted separately because we may be adding the key + * as part of creation of the key, in which case the reference counter was + * already initialized. Also note we don't need RWLOCK for the reference + * counter: it's protected by a separate lock. + */ +static isc_result_t +keyring_add(dns_tsig_keyring_t *ring, const dns_name_t *name, + dns_tsigkey_t *tkey) { + isc_result_t result; + + RWLOCK(&ring->lock, isc_rwlocktype_write); + ring->writecount++; + + /* + * Do on the fly cleaning. Find some nodes we might not + * want around any more. + */ + if (ring->writecount > 10) { + cleanup_ring(ring); + ring->writecount = 0; + } + + result = dns_rbt_addname(ring->keys, name, tkey); + if (result == ISC_R_SUCCESS && tkey->generated) { + /* + * Add the new key to the LRU list and remove the least + * recently used key if there are too many keys on the list. + */ + ISC_LIST_APPEND(ring->lru, tkey, link); + if (ring->generated++ > ring->maxgenerated) { + remove_fromring(ISC_LIST_HEAD(ring->lru)); + } + } + RWUNLOCK(&ring->lock, isc_rwlocktype_write); + + return (result); +} + +isc_result_t +dns_tsigkey_createfromkey(const dns_name_t *name, const dns_name_t *algorithm, + dst_key_t *dstkey, bool generated, + const dns_name_t *creator, isc_stdtime_t inception, + isc_stdtime_t expire, isc_mem_t *mctx, + dns_tsig_keyring_t *ring, dns_tsigkey_t **key) { + dns_tsigkey_t *tkey; + isc_result_t ret; + unsigned int refs = 0; + unsigned int dstalg = 0; + + REQUIRE(key == NULL || *key == NULL); + REQUIRE(name != NULL); + REQUIRE(algorithm != NULL); + REQUIRE(mctx != NULL); + REQUIRE(key != NULL || ring != NULL); + + tkey = isc_mem_get(mctx, sizeof(dns_tsigkey_t)); + + dns_name_init(&tkey->name, NULL); + dns_name_dup(name, mctx, &tkey->name); + (void)dns_name_downcase(&tkey->name, &tkey->name, NULL); + + /* Check against known algorithm names */ + dstalg = dns__tsig_algfromname(algorithm); + if (dstalg != 0) { + /* + * 'algorithm' must be set to a static pointer + * so that dns__tsig_algallocated() can compare them. + */ + tkey->algorithm = dns__tsig_algnamefromname(algorithm); + if (dstkey != NULL && dst_key_alg(dstkey) != dstalg) { + ret = DNS_R_BADALG; + goto cleanup_name; + } + } else { + dns_name_t *tmpname; + if (dstkey != NULL) { + ret = DNS_R_BADALG; + goto cleanup_name; + } + tmpname = isc_mem_get(mctx, sizeof(dns_name_t)); + dns_name_init(tmpname, NULL); + dns_name_dup(algorithm, mctx, tmpname); + (void)dns_name_downcase(tmpname, tmpname, NULL); + tkey->algorithm = tmpname; + } + + if (creator != NULL) { + tkey->creator = isc_mem_get(mctx, sizeof(dns_name_t)); + dns_name_init(tkey->creator, NULL); + dns_name_dup(creator, mctx, tkey->creator); + } else { + tkey->creator = NULL; + } + + tkey->key = NULL; + if (dstkey != NULL) { + dst_key_attach(dstkey, &tkey->key); + } + tkey->ring = ring; + + if (key != NULL) { + refs = 1; + } + if (ring != NULL) { + refs++; + } + + isc_refcount_init(&tkey->refs, refs); + + tkey->generated = generated; + tkey->inception = inception; + tkey->expire = expire; + tkey->mctx = NULL; + isc_mem_attach(mctx, &tkey->mctx); + ISC_LINK_INIT(tkey, link); + + tkey->magic = TSIG_MAGIC; + + if (ring != NULL) { + ret = keyring_add(ring, name, tkey); + if (ret != ISC_R_SUCCESS) { + goto cleanup_refs; + } + } + + /* + * Ignore this if it's a GSS key, since the key size is meaningless. + */ + if (dstkey != NULL && dst_key_size(dstkey) < 64 && + dstalg != DST_ALG_GSSAPI) + { + char namestr[DNS_NAME_FORMATSIZE]; + dns_name_format(name, namestr, sizeof(namestr)); + isc_log_write(dns_lctx, DNS_LOGCATEGORY_DNSSEC, + DNS_LOGMODULE_TSIG, ISC_LOG_INFO, + "the key '%s' is too short to be secure", + namestr); + } + + if (key != NULL) { + *key = tkey; + } + + return (ISC_R_SUCCESS); + +cleanup_refs: + tkey->magic = 0; + while (refs-- > 0) { + isc_refcount_decrement0(&tkey->refs); + } + isc_refcount_destroy(&tkey->refs); + + if (tkey->key != NULL) { + dst_key_free(&tkey->key); + } + if (tkey->creator != NULL) { + dns_name_free(tkey->creator, mctx); + isc_mem_put(mctx, tkey->creator, sizeof(dns_name_t)); + } + if (dns__tsig_algallocated(tkey->algorithm)) { + dns_name_t *tmpname; + DE_CONST(tkey->algorithm, tmpname); + if (dns_name_dynamic(tmpname)) { + dns_name_free(tmpname, mctx); + } + isc_mem_put(mctx, tmpname, sizeof(dns_name_t)); + } +cleanup_name: + dns_name_free(&tkey->name, mctx); + isc_mem_put(mctx, tkey, sizeof(dns_tsigkey_t)); + + return (ret); +} + +/* + * Find a few nodes to destroy if possible. + */ +static void +cleanup_ring(dns_tsig_keyring_t *ring) { + isc_result_t result; + dns_rbtnodechain_t chain; + dns_name_t foundname; + dns_fixedname_t fixedorigin; + dns_name_t *origin; + isc_stdtime_t now; + dns_rbtnode_t *node; + dns_tsigkey_t *tkey; + + /* + * Start up a new iterator each time. + */ + isc_stdtime_get(&now); + dns_name_init(&foundname, NULL); + origin = dns_fixedname_initname(&fixedorigin); + +again: + dns_rbtnodechain_init(&chain); + result = dns_rbtnodechain_first(&chain, ring->keys, &foundname, origin); + if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) { + dns_rbtnodechain_invalidate(&chain); + return; + } + + for (;;) { + node = NULL; + dns_rbtnodechain_current(&chain, &foundname, origin, &node); + tkey = node->data; + if (tkey != NULL) { + if (tkey->generated && + isc_refcount_current(&tkey->refs) == 1 && + tkey->inception != tkey->expire && + tkey->expire < now) + { + tsig_log(tkey, 2, "tsig expire: deleting"); + /* delete the key */ + dns_rbtnodechain_invalidate(&chain); + remove_fromring(tkey); + goto again; + } + } + result = dns_rbtnodechain_next(&chain, &foundname, origin); + if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) { + dns_rbtnodechain_invalidate(&chain); + return; + } + } +} + +static void +destroyring(dns_tsig_keyring_t *ring) { + isc_refcount_destroy(&ring->references); + dns_rbt_destroy(&ring->keys); + isc_rwlock_destroy(&ring->lock); + isc_mem_putanddetach(&ring->mctx, ring, sizeof(dns_tsig_keyring_t)); +} + +/* + * Look up the DST_ALG_ constant for a given name. + */ +unsigned int +dns__tsig_algfromname(const dns_name_t *algorithm) { + int i; + int n = sizeof(known_algs) / sizeof(*known_algs); + for (i = 0; i < n; ++i) { + const dns_name_t *name = known_algs[i].name; + if (algorithm == name || dns_name_equal(algorithm, name)) { + return (known_algs[i].dstalg); + } + } + return (0); +} + +/* + * Convert an algorithm name into a pointer to the + * corresponding pre-defined dns_name_t structure. + */ +const dns_name_t * +dns__tsig_algnamefromname(const dns_name_t *algorithm) { + int i; + int n = sizeof(known_algs) / sizeof(*known_algs); + for (i = 0; i < n; ++i) { + const dns_name_t *name = known_algs[i].name; + if (algorithm == name || dns_name_equal(algorithm, name)) { + return (name); + } + } + return (NULL); +} + +/* + * Test whether the passed algorithm is NOT a pointer to one of the + * pre-defined known algorithms (and therefore one that has been + * dynamically allocated). + * + * This will return an incorrect result if passed a dynamically allocated + * dns_name_t that happens to match one of the pre-defined names. + */ +bool +dns__tsig_algallocated(const dns_name_t *algorithm) { + int i; + int n = sizeof(known_algs) / sizeof(*known_algs); + for (i = 0; i < n; ++i) { + const dns_name_t *name = known_algs[i].name; + if (algorithm == name) { + return (false); + } + } + return (true); +} + +static isc_result_t +restore_key(dns_tsig_keyring_t *ring, isc_stdtime_t now, FILE *fp) { + dst_key_t *dstkey = NULL; + char namestr[1024]; + char creatorstr[1024]; + char algorithmstr[1024]; + char keystr[4096]; + unsigned int inception, expire; + int n; + isc_buffer_t b; + dns_name_t *name, *creator, *algorithm; + dns_fixedname_t fname, fcreator, falgorithm; + isc_result_t result; + unsigned int dstalg; + + n = fscanf(fp, "%1023s %1023s %u %u %1023s %4095s\n", namestr, + creatorstr, &inception, &expire, algorithmstr, keystr); + if (n == EOF) { + return (ISC_R_NOMORE); + } + if (n != 6) { + return (ISC_R_FAILURE); + } + + if (isc_serial_lt(expire, now)) { + return (DNS_R_EXPIRED); + } + + name = dns_fixedname_initname(&fname); + isc_buffer_init(&b, namestr, strlen(namestr)); + isc_buffer_add(&b, strlen(namestr)); + result = dns_name_fromtext(name, &b, dns_rootname, 0, NULL); + if (result != ISC_R_SUCCESS) { + return (result); + } + + creator = dns_fixedname_initname(&fcreator); + isc_buffer_init(&b, creatorstr, strlen(creatorstr)); + isc_buffer_add(&b, strlen(creatorstr)); + result = dns_name_fromtext(creator, &b, dns_rootname, 0, NULL); + if (result != ISC_R_SUCCESS) { + return (result); + } + + algorithm = dns_fixedname_initname(&falgorithm); + isc_buffer_init(&b, algorithmstr, strlen(algorithmstr)); + isc_buffer_add(&b, strlen(algorithmstr)); + result = dns_name_fromtext(algorithm, &b, dns_rootname, 0, NULL); + if (result != ISC_R_SUCCESS) { + return (result); + } + + dstalg = dns__tsig_algfromname(algorithm); + if (dstalg == 0) { + return (DNS_R_BADALG); + } + + result = dst_key_restore(name, dstalg, DNS_KEYOWNER_ENTITY, + DNS_KEYPROTO_DNSSEC, dns_rdataclass_in, + ring->mctx, keystr, &dstkey); + if (result != ISC_R_SUCCESS) { + return (result); + } + + result = dns_tsigkey_createfromkey(name, algorithm, dstkey, true, + creator, inception, expire, + ring->mctx, ring, NULL); + if (dstkey != NULL) { + dst_key_free(&dstkey); + } + return (result); +} + +static void +dump_key(dns_tsigkey_t *tkey, FILE *fp) { + char *buffer = NULL; + int length = 0; + char namestr[DNS_NAME_FORMATSIZE]; + char creatorstr[DNS_NAME_FORMATSIZE]; + char algorithmstr[DNS_NAME_FORMATSIZE]; + isc_result_t result; + + REQUIRE(tkey != NULL); + REQUIRE(fp != NULL); + + dns_name_format(&tkey->name, namestr, sizeof(namestr)); + dns_name_format(tkey->creator, creatorstr, sizeof(creatorstr)); + dns_name_format(tkey->algorithm, algorithmstr, sizeof(algorithmstr)); + result = dst_key_dump(tkey->key, tkey->mctx, &buffer, &length); + if (result == ISC_R_SUCCESS) { + fprintf(fp, "%s %s %u %u %s %.*s\n", namestr, creatorstr, + tkey->inception, tkey->expire, algorithmstr, length, + buffer); + } + if (buffer != NULL) { + isc_mem_put(tkey->mctx, buffer, length); + } +} + +isc_result_t +dns_tsigkeyring_dumpanddetach(dns_tsig_keyring_t **ringp, FILE *fp) { + isc_result_t result; + dns_rbtnodechain_t chain; + dns_name_t foundname; + dns_fixedname_t fixedorigin; + dns_name_t *origin; + isc_stdtime_t now; + dns_rbtnode_t *node; + dns_tsigkey_t *tkey; + dns_tsig_keyring_t *ring; + + REQUIRE(ringp != NULL && *ringp != NULL); + + ring = *ringp; + *ringp = NULL; + + if (isc_refcount_decrement(&ring->references) > 1) { + return (DNS_R_CONTINUE); + } + + isc_stdtime_get(&now); + dns_name_init(&foundname, NULL); + origin = dns_fixedname_initname(&fixedorigin); + dns_rbtnodechain_init(&chain); + result = dns_rbtnodechain_first(&chain, ring->keys, &foundname, origin); + if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) { + dns_rbtnodechain_invalidate(&chain); + goto destroy; + } + + for (;;) { + node = NULL; + dns_rbtnodechain_current(&chain, &foundname, origin, &node); + tkey = node->data; + if (tkey != NULL && tkey->generated && tkey->expire >= now) { + dump_key(tkey, fp); + } + result = dns_rbtnodechain_next(&chain, &foundname, origin); + if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) { + dns_rbtnodechain_invalidate(&chain); + if (result == ISC_R_NOMORE) { + result = ISC_R_SUCCESS; + } + goto destroy; + } + } + +destroy: + destroyring(ring); + return (result); +} + +const dns_name_t * +dns_tsigkey_identity(const dns_tsigkey_t *tsigkey) { + REQUIRE(tsigkey == NULL || VALID_TSIG_KEY(tsigkey)); + + if (tsigkey == NULL) { + return (NULL); + } + if (tsigkey->generated) { + return (tsigkey->creator); + } else { + return (&tsigkey->name); + } +} + +isc_result_t +dns_tsigkey_create(const dns_name_t *name, const dns_name_t *algorithm, + unsigned char *secret, int length, bool generated, + const dns_name_t *creator, isc_stdtime_t inception, + isc_stdtime_t expire, isc_mem_t *mctx, + dns_tsig_keyring_t *ring, dns_tsigkey_t **key) { + dst_key_t *dstkey = NULL; + isc_result_t result; + unsigned int dstalg = 0; + + REQUIRE(length >= 0); + if (length > 0) { + REQUIRE(secret != NULL); + } + + dstalg = dns__tsig_algfromname(algorithm); + if (dns__tsig_algvalid(dstalg)) { + if (secret != NULL) { + isc_buffer_t b; + + isc_buffer_init(&b, secret, length); + isc_buffer_add(&b, length); + result = dst_key_frombuffer( + name, dstalg, DNS_KEYOWNER_ENTITY, + DNS_KEYPROTO_DNSSEC, dns_rdataclass_in, &b, + mctx, &dstkey); + if (result != ISC_R_SUCCESS) { + return (result); + } + } + } else if (length > 0) { + return (DNS_R_BADALG); + } + + result = dns_tsigkey_createfromkey(name, algorithm, dstkey, generated, + creator, inception, expire, mctx, + ring, key); + if (dstkey != NULL) { + dst_key_free(&dstkey); + } + return (result); +} + +void +dns_tsigkey_attach(dns_tsigkey_t *source, dns_tsigkey_t **targetp) { + REQUIRE(VALID_TSIG_KEY(source)); + REQUIRE(targetp != NULL && *targetp == NULL); + + isc_refcount_increment(&source->refs); + *targetp = source; +} + +static void +tsigkey_free(dns_tsigkey_t *key) { + REQUIRE(VALID_TSIG_KEY(key)); + + key->magic = 0; + dns_name_free(&key->name, key->mctx); + if (dns__tsig_algallocated(key->algorithm)) { + dns_name_t *name; + DE_CONST(key->algorithm, name); + dns_name_free(name, key->mctx); + isc_mem_put(key->mctx, name, sizeof(dns_name_t)); + } + if (key->key != NULL) { + dst_key_free(&key->key); + } + if (key->creator != NULL) { + dns_name_free(key->creator, key->mctx); + isc_mem_put(key->mctx, key->creator, sizeof(dns_name_t)); + } + isc_mem_putanddetach(&key->mctx, key, sizeof(dns_tsigkey_t)); +} + +void +dns_tsigkey_detach(dns_tsigkey_t **keyp) { + REQUIRE(keyp != NULL && VALID_TSIG_KEY(*keyp)); + dns_tsigkey_t *key = *keyp; + *keyp = NULL; + + if (isc_refcount_decrement(&key->refs) == 1) { + isc_refcount_destroy(&key->refs); + tsigkey_free(key); + } +} + +void +dns_tsigkey_setdeleted(dns_tsigkey_t *key) { + REQUIRE(VALID_TSIG_KEY(key)); + REQUIRE(key->ring != NULL); + + RWLOCK(&key->ring->lock, isc_rwlocktype_write); + remove_fromring(key); + RWUNLOCK(&key->ring->lock, isc_rwlocktype_write); +} + +isc_result_t +dns_tsig_sign(dns_message_t *msg) { + dns_tsigkey_t *key = NULL; + dns_rdata_any_tsig_t tsig, querytsig; + unsigned char data[128]; + isc_buffer_t databuf, sigbuf; + isc_buffer_t *dynbuf = NULL; + dns_name_t *owner = NULL; + dns_rdata_t *rdata = NULL; + dns_rdatalist_t *datalist = NULL; + dns_rdataset_t *dataset = NULL; + isc_region_t r; + isc_stdtime_t now; + isc_mem_t *mctx; + dst_context_t *ctx = NULL; + isc_result_t ret; + unsigned char badtimedata[BADTIMELEN]; + unsigned int sigsize = 0; + bool response; + + REQUIRE(msg != NULL); + key = dns_message_gettsigkey(msg); + REQUIRE(VALID_TSIG_KEY(key)); + + /* + * If this is a response, there should be a TSIG in the query with the + * the exception if this is a TKEY request (see RFC 3645, Section 2.2). + */ + response = is_response(msg); + if (response && msg->querytsig == NULL) { + if (msg->tkey != 1) { + return (DNS_R_EXPECTEDTSIG); + } + } + + mctx = msg->mctx; + + tsig.mctx = mctx; + tsig.common.rdclass = dns_rdataclass_any; + tsig.common.rdtype = dns_rdatatype_tsig; + ISC_LINK_INIT(&tsig.common, link); + dns_name_init(&tsig.algorithm, NULL); + dns_name_clone(key->algorithm, &tsig.algorithm); + + isc_stdtime_get(&now); + tsig.timesigned = now + msg->timeadjust; + tsig.fudge = DNS_TSIG_FUDGE; + + tsig.originalid = msg->id; + + isc_buffer_init(&databuf, data, sizeof(data)); + + if (response) { + tsig.error = msg->querytsigstatus; + } else { + tsig.error = dns_rcode_noerror; + } + + if (tsig.error != dns_tsigerror_badtime) { + tsig.otherlen = 0; + tsig.other = NULL; + } else { + isc_buffer_t otherbuf; + + tsig.otherlen = BADTIMELEN; + tsig.other = badtimedata; + isc_buffer_init(&otherbuf, tsig.other, tsig.otherlen); + isc_buffer_putuint48(&otherbuf, tsig.timesigned); + } + + if ((key->key != NULL) && (tsig.error != dns_tsigerror_badsig) && + (tsig.error != dns_tsigerror_badkey)) + { + unsigned char header[DNS_MESSAGE_HEADERLEN]; + isc_buffer_t headerbuf; + uint16_t digestbits; + bool querytsig_ok = false; + + /* + * If it is a response, we assume that the request MAC + * has validated at this point. This is why we include a + * MAC length > 0 in the reply. + */ + ret = dst_context_create(key->key, mctx, DNS_LOGCATEGORY_DNSSEC, + true, 0, &ctx); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + + /* + * If this is a response, and if there was a TSIG in + * the query, digest the request's MAC. + * + * (Note: querytsig should be non-NULL for all + * responses except TKEY responses. Those may be signed + * with the newly-negotiated TSIG key even if the query + * wasn't signed.) + */ + if (response && msg->querytsig != NULL) { + dns_rdata_t querytsigrdata = DNS_RDATA_INIT; + + INSIST(msg->verified_sig); + + ret = dns_rdataset_first(msg->querytsig); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + dns_rdataset_current(msg->querytsig, &querytsigrdata); + ret = dns_rdata_tostruct(&querytsigrdata, &querytsig, + NULL); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + isc_buffer_putuint16(&databuf, querytsig.siglen); + if (isc_buffer_availablelength(&databuf) < + querytsig.siglen) + { + ret = ISC_R_NOSPACE; + goto cleanup_context; + } + isc_buffer_putmem(&databuf, querytsig.signature, + querytsig.siglen); + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + querytsig_ok = true; + } + + /* + * Digest the header. + */ + isc_buffer_init(&headerbuf, header, sizeof(header)); + dns_message_renderheader(msg, &headerbuf); + isc_buffer_usedregion(&headerbuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest the remainder of the message. + */ + isc_buffer_usedregion(msg->buffer, &r); + isc_region_consume(&r, DNS_MESSAGE_HEADERLEN); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + if (msg->tcp_continuation == 0) { + /* + * Digest the name, class, ttl, alg. + */ + dns_name_toregion(&key->name, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + isc_buffer_clear(&databuf); + isc_buffer_putuint16(&databuf, dns_rdataclass_any); + isc_buffer_putuint32(&databuf, 0); /* ttl */ + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + dns_name_toregion(&tsig.algorithm, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + } + /* Digest the timesigned and fudge */ + isc_buffer_clear(&databuf); + if (tsig.error == dns_tsigerror_badtime && querytsig_ok) { + tsig.timesigned = querytsig.timesigned; + } + isc_buffer_putuint48(&databuf, tsig.timesigned); + isc_buffer_putuint16(&databuf, tsig.fudge); + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + if (msg->tcp_continuation == 0) { + /* + * Digest the error and other data length. + */ + isc_buffer_clear(&databuf); + isc_buffer_putuint16(&databuf, tsig.error); + isc_buffer_putuint16(&databuf, tsig.otherlen); + + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest other data. + */ + if (tsig.otherlen > 0) { + r.length = tsig.otherlen; + r.base = tsig.other; + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + } + } + + ret = dst_key_sigsize(key->key, &sigsize); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + tsig.signature = isc_mem_get(mctx, sigsize); + + isc_buffer_init(&sigbuf, tsig.signature, sigsize); + ret = dst_context_sign(ctx, &sigbuf); + if (ret != ISC_R_SUCCESS) { + goto cleanup_signature; + } + dst_context_destroy(&ctx); + digestbits = dst_key_getbits(key->key); + if (digestbits != 0) { + unsigned int bytes = (digestbits + 7) / 8; + if (querytsig_ok && bytes < querytsig.siglen) { + bytes = querytsig.siglen; + } + if (bytes > isc_buffer_usedlength(&sigbuf)) { + bytes = isc_buffer_usedlength(&sigbuf); + } + tsig.siglen = bytes; + } else { + tsig.siglen = isc_buffer_usedlength(&sigbuf); + } + } else { + tsig.siglen = 0; + tsig.signature = NULL; + } + + ret = dns_message_gettemprdata(msg, &rdata); + if (ret != ISC_R_SUCCESS) { + goto cleanup_signature; + } + isc_buffer_allocate(msg->mctx, &dynbuf, 512); + ret = dns_rdata_fromstruct(rdata, dns_rdataclass_any, + dns_rdatatype_tsig, &tsig, dynbuf); + if (ret != ISC_R_SUCCESS) { + goto cleanup_dynbuf; + } + + dns_message_takebuffer(msg, &dynbuf); + + if (tsig.signature != NULL) { + isc_mem_put(mctx, tsig.signature, sigsize); + tsig.signature = NULL; + } + + ret = dns_message_gettempname(msg, &owner); + if (ret != ISC_R_SUCCESS) { + goto cleanup_rdata; + } + dns_name_copynf(&key->name, owner); + + ret = dns_message_gettemprdatalist(msg, &datalist); + if (ret != ISC_R_SUCCESS) { + goto cleanup_owner; + } + + ret = dns_message_gettemprdataset(msg, &dataset); + if (ret != ISC_R_SUCCESS) { + goto cleanup_rdatalist; + } + datalist->rdclass = dns_rdataclass_any; + datalist->type = dns_rdatatype_tsig; + ISC_LIST_APPEND(datalist->rdata, rdata, link); + RUNTIME_CHECK(dns_rdatalist_tordataset(datalist, dataset) == + ISC_R_SUCCESS); + msg->tsig = dataset; + msg->tsigname = owner; + + /* Windows does not like the tsig name being compressed. */ + msg->tsigname->attributes |= DNS_NAMEATTR_NOCOMPRESS; + + return (ISC_R_SUCCESS); + +cleanup_rdatalist: + dns_message_puttemprdatalist(msg, &datalist); +cleanup_owner: + dns_message_puttempname(msg, &owner); + goto cleanup_rdata; +cleanup_dynbuf: + isc_buffer_free(&dynbuf); +cleanup_rdata: + dns_message_puttemprdata(msg, &rdata); +cleanup_signature: + if (tsig.signature != NULL) { + isc_mem_put(mctx, tsig.signature, sigsize); + } +cleanup_context: + if (ctx != NULL) { + dst_context_destroy(&ctx); + } + return (ret); +} + +isc_result_t +dns_tsig_verify(isc_buffer_t *source, dns_message_t *msg, + dns_tsig_keyring_t *ring1, dns_tsig_keyring_t *ring2) { + dns_rdata_any_tsig_t tsig, querytsig; + isc_region_t r, source_r, header_r, sig_r; + isc_buffer_t databuf; + unsigned char data[32]; + dns_name_t *keyname; + dns_rdata_t rdata = DNS_RDATA_INIT; + isc_stdtime_t now; + isc_result_t ret; + dns_tsigkey_t *tsigkey; + dst_key_t *key = NULL; + unsigned char header[DNS_MESSAGE_HEADERLEN]; + dst_context_t *ctx = NULL; + isc_mem_t *mctx; + uint16_t addcount, id; + unsigned int siglen; + unsigned int alg; + bool response; + + REQUIRE(source != NULL); + REQUIRE(DNS_MESSAGE_VALID(msg)); + tsigkey = dns_message_gettsigkey(msg); + response = is_response(msg); + + REQUIRE(tsigkey == NULL || VALID_TSIG_KEY(tsigkey)); + + msg->verify_attempted = 1; + msg->verified_sig = 0; + msg->tsigstatus = dns_tsigerror_badsig; + + if (msg->tcp_continuation) { + if (tsigkey == NULL || msg->querytsig == NULL) { + return (DNS_R_UNEXPECTEDTSIG); + } + return (tsig_verify_tcp(source, msg)); + } + + /* + * There should be a TSIG record... + */ + if (msg->tsig == NULL) { + return (DNS_R_EXPECTEDTSIG); + } + + /* + * If this is a response and there's no key or query TSIG, there + * shouldn't be one on the response. + */ + if (response && (tsigkey == NULL || msg->querytsig == NULL)) { + return (DNS_R_UNEXPECTEDTSIG); + } + + mctx = msg->mctx; + + /* + * If we're here, we know the message is well formed and contains a + * TSIG record. + */ + + keyname = msg->tsigname; + ret = dns_rdataset_first(msg->tsig); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + dns_rdataset_current(msg->tsig, &rdata); + ret = dns_rdata_tostruct(&rdata, &tsig, NULL); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + dns_rdata_reset(&rdata); + if (response) { + ret = dns_rdataset_first(msg->querytsig); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + dns_rdataset_current(msg->querytsig, &rdata); + ret = dns_rdata_tostruct(&rdata, &querytsig, NULL); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + } + + /* + * Do the key name and algorithm match that of the query? + */ + if (response && + (!dns_name_equal(keyname, &tsigkey->name) || + !dns_name_equal(&tsig.algorithm, &querytsig.algorithm))) + { + msg->tsigstatus = dns_tsigerror_badkey; + tsig_log(msg->tsigkey, 2, + "key name and algorithm do not match"); + return (DNS_R_TSIGVERIFYFAILURE); + } + + /* + * Get the current time. + */ + isc_stdtime_get(&now); + + /* + * Find dns_tsigkey_t based on keyname. + */ + if (tsigkey == NULL) { + ret = ISC_R_NOTFOUND; + if (ring1 != NULL) { + ret = dns_tsigkey_find(&tsigkey, keyname, + &tsig.algorithm, ring1); + } + if (ret == ISC_R_NOTFOUND && ring2 != NULL) { + ret = dns_tsigkey_find(&tsigkey, keyname, + &tsig.algorithm, ring2); + } + if (ret != ISC_R_SUCCESS) { + msg->tsigstatus = dns_tsigerror_badkey; + ret = dns_tsigkey_create(keyname, &tsig.algorithm, NULL, + 0, false, NULL, now, now, mctx, + NULL, &msg->tsigkey); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + tsig_log(msg->tsigkey, 2, "unknown key"); + return (DNS_R_TSIGVERIFYFAILURE); + } + msg->tsigkey = tsigkey; + } + + key = tsigkey->key; + + /* + * Check digest length. + */ + alg = dst_key_alg(key); + ret = dst_key_sigsize(key, &siglen); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + if (dns__tsig_algvalid(alg)) { + if (tsig.siglen > siglen) { + tsig_log(msg->tsigkey, 2, "signature length too big"); + return (DNS_R_FORMERR); + } + if (tsig.siglen > 0 && + (tsig.siglen < 10 || tsig.siglen < ((siglen + 1) / 2))) + { + tsig_log(msg->tsigkey, 2, + "signature length below minimum"); + return (DNS_R_FORMERR); + } + } + + if (tsig.siglen > 0) { + uint16_t addcount_n; + + sig_r.base = tsig.signature; + sig_r.length = tsig.siglen; + + ret = dst_context_create(key, mctx, DNS_LOGCATEGORY_DNSSEC, + false, 0, &ctx); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + + if (response) { + isc_buffer_init(&databuf, data, sizeof(data)); + isc_buffer_putuint16(&databuf, querytsig.siglen); + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + if (querytsig.siglen > 0) { + r.length = querytsig.siglen; + r.base = querytsig.signature; + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + } + } + + /* + * Extract the header. + */ + isc_buffer_usedregion(source, &r); + memmove(header, r.base, DNS_MESSAGE_HEADERLEN); + isc_region_consume(&r, DNS_MESSAGE_HEADERLEN); + + /* + * Decrement the additional field counter. + */ + memmove(&addcount, &header[DNS_MESSAGE_HEADERLEN - 2], 2); + addcount_n = ntohs(addcount); + addcount = htons((uint16_t)(addcount_n - 1)); + memmove(&header[DNS_MESSAGE_HEADERLEN - 2], &addcount, 2); + + /* + * Put in the original id. + */ + id = htons(tsig.originalid); + memmove(&header[0], &id, 2); + + /* + * Digest the modified header. + */ + header_r.base = (unsigned char *)header; + header_r.length = DNS_MESSAGE_HEADERLEN; + ret = dst_context_adddata(ctx, &header_r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest all non-TSIG records. + */ + isc_buffer_usedregion(source, &source_r); + r.base = source_r.base + DNS_MESSAGE_HEADERLEN; + r.length = msg->sigstart - DNS_MESSAGE_HEADERLEN; + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest the key name. + */ + dns_name_toregion(&tsigkey->name, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + isc_buffer_init(&databuf, data, sizeof(data)); + isc_buffer_putuint16(&databuf, tsig.common.rdclass); + isc_buffer_putuint32(&databuf, msg->tsig->ttl); + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest the key algorithm. + */ + dns_name_toregion(tsigkey->algorithm, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + isc_buffer_clear(&databuf); + isc_buffer_putuint48(&databuf, tsig.timesigned); + isc_buffer_putuint16(&databuf, tsig.fudge); + isc_buffer_putuint16(&databuf, tsig.error); + isc_buffer_putuint16(&databuf, tsig.otherlen); + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + if (tsig.otherlen > 0) { + r.base = tsig.other; + r.length = tsig.otherlen; + ret = dst_context_adddata(ctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + } + + ret = dst_context_verify(ctx, &sig_r); + if (ret == DST_R_VERIFYFAILURE) { + ret = DNS_R_TSIGVERIFYFAILURE; + tsig_log(msg->tsigkey, 2, + "signature failed to verify(1)"); + goto cleanup_context; + } else if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + msg->verified_sig = 1; + } else if (!response || (tsig.error != dns_tsigerror_badsig && + tsig.error != dns_tsigerror_badkey)) + { + tsig_log(msg->tsigkey, 2, "signature was empty"); + return (DNS_R_TSIGVERIFYFAILURE); + } + + /* + * Here at this point, the MAC has been verified. Even if any of + * the following code returns a TSIG error, the reply will be + * signed and WILL always include the request MAC in the digest + * computation. + */ + + /* + * Is the time ok? + */ + if (now + msg->timeadjust > tsig.timesigned + tsig.fudge) { + msg->tsigstatus = dns_tsigerror_badtime; + tsig_log(msg->tsigkey, 2, "signature has expired"); + ret = DNS_R_CLOCKSKEW; + goto cleanup_context; + } else if (now + msg->timeadjust < tsig.timesigned - tsig.fudge) { + msg->tsigstatus = dns_tsigerror_badtime; + tsig_log(msg->tsigkey, 2, "signature is in the future"); + ret = DNS_R_CLOCKSKEW; + goto cleanup_context; + } + + if (dns__tsig_algvalid(alg)) { + uint16_t digestbits = dst_key_getbits(key); + + if (tsig.siglen > 0 && digestbits != 0 && + tsig.siglen < ((digestbits + 7) / 8)) + { + msg->tsigstatus = dns_tsigerror_badtrunc; + tsig_log(msg->tsigkey, 2, + "truncated signature length too small"); + ret = DNS_R_TSIGVERIFYFAILURE; + goto cleanup_context; + } + if (tsig.siglen > 0 && digestbits == 0 && tsig.siglen < siglen) + { + msg->tsigstatus = dns_tsigerror_badtrunc; + tsig_log(msg->tsigkey, 2, "signature length too small"); + ret = DNS_R_TSIGVERIFYFAILURE; + goto cleanup_context; + } + } + + if (response && tsig.error != dns_rcode_noerror) { + msg->tsigstatus = tsig.error; + if (tsig.error == dns_tsigerror_badtime) { + ret = DNS_R_CLOCKSKEW; + } else { + ret = DNS_R_TSIGERRORSET; + } + goto cleanup_context; + } + + msg->tsigstatus = dns_rcode_noerror; + ret = ISC_R_SUCCESS; + +cleanup_context: + if (ctx != NULL) { + dst_context_destroy(&ctx); + } + + return (ret); +} + +static isc_result_t +tsig_verify_tcp(isc_buffer_t *source, dns_message_t *msg) { + dns_rdata_any_tsig_t tsig, querytsig; + isc_region_t r, source_r, header_r, sig_r; + isc_buffer_t databuf; + unsigned char data[32]; + dns_name_t *keyname; + dns_rdata_t rdata = DNS_RDATA_INIT; + isc_stdtime_t now; + isc_result_t ret; + dns_tsigkey_t *tsigkey; + dst_key_t *key = NULL; + unsigned char header[DNS_MESSAGE_HEADERLEN]; + uint16_t addcount, id; + bool has_tsig = false; + isc_mem_t *mctx; + unsigned int siglen; + unsigned int alg; + + REQUIRE(source != NULL); + REQUIRE(msg != NULL); + REQUIRE(dns_message_gettsigkey(msg) != NULL); + REQUIRE(msg->tcp_continuation == 1); + REQUIRE(msg->querytsig != NULL); + + msg->verified_sig = 0; + msg->tsigstatus = dns_tsigerror_badsig; + + if (!is_response(msg)) { + return (DNS_R_EXPECTEDRESPONSE); + } + + mctx = msg->mctx; + + tsigkey = dns_message_gettsigkey(msg); + key = tsigkey->key; + + /* + * Extract and parse the previous TSIG + */ + ret = dns_rdataset_first(msg->querytsig); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + dns_rdataset_current(msg->querytsig, &rdata); + ret = dns_rdata_tostruct(&rdata, &querytsig, NULL); + if (ret != ISC_R_SUCCESS) { + return (ret); + } + dns_rdata_reset(&rdata); + + /* + * If there is a TSIG in this message, do some checks. + */ + if (msg->tsig != NULL) { + has_tsig = true; + + keyname = msg->tsigname; + ret = dns_rdataset_first(msg->tsig); + if (ret != ISC_R_SUCCESS) { + goto cleanup_querystruct; + } + dns_rdataset_current(msg->tsig, &rdata); + ret = dns_rdata_tostruct(&rdata, &tsig, NULL); + if (ret != ISC_R_SUCCESS) { + goto cleanup_querystruct; + } + + /* + * Do the key name and algorithm match that of the query? + */ + if (!dns_name_equal(keyname, &tsigkey->name) || + !dns_name_equal(&tsig.algorithm, &querytsig.algorithm)) + { + msg->tsigstatus = dns_tsigerror_badkey; + ret = DNS_R_TSIGVERIFYFAILURE; + tsig_log(msg->tsigkey, 2, + "key name and algorithm do not match"); + goto cleanup_querystruct; + } + + /* + * Check digest length. + */ + alg = dst_key_alg(key); + ret = dst_key_sigsize(key, &siglen); + if (ret != ISC_R_SUCCESS) { + goto cleanup_querystruct; + } + if (dns__tsig_algvalid(alg)) { + if (tsig.siglen > siglen) { + tsig_log(tsigkey, 2, + "signature length too big"); + ret = DNS_R_FORMERR; + goto cleanup_querystruct; + } + if (tsig.siglen > 0 && + (tsig.siglen < 10 || + tsig.siglen < ((siglen + 1) / 2))) + { + tsig_log(tsigkey, 2, + "signature length below minimum"); + ret = DNS_R_FORMERR; + goto cleanup_querystruct; + } + } + } + + if (msg->tsigctx == NULL) { + ret = dst_context_create(key, mctx, DNS_LOGCATEGORY_DNSSEC, + false, 0, &msg->tsigctx); + if (ret != ISC_R_SUCCESS) { + goto cleanup_querystruct; + } + + /* + * Digest the length of the query signature + */ + isc_buffer_init(&databuf, data, sizeof(data)); + isc_buffer_putuint16(&databuf, querytsig.siglen); + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(msg->tsigctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest the data of the query signature + */ + if (querytsig.siglen > 0) { + r.length = querytsig.siglen; + r.base = querytsig.signature; + ret = dst_context_adddata(msg->tsigctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + } + } + + /* + * Extract the header. + */ + isc_buffer_usedregion(source, &r); + memmove(header, r.base, DNS_MESSAGE_HEADERLEN); + isc_region_consume(&r, DNS_MESSAGE_HEADERLEN); + + /* + * Decrement the additional field counter if necessary. + */ + if (has_tsig) { + uint16_t addcount_n; + + memmove(&addcount, &header[DNS_MESSAGE_HEADERLEN - 2], 2); + addcount_n = ntohs(addcount); + addcount = htons((uint16_t)(addcount_n - 1)); + memmove(&header[DNS_MESSAGE_HEADERLEN - 2], &addcount, 2); + + /* + * Put in the original id. + * + * XXX Can TCP transfers be forwarded? How would that + * work? + */ + /* cppcheck-suppress uninitStructMember + * symbolName=tsig.originalid */ + id = htons(tsig.originalid); + memmove(&header[0], &id, 2); + } + + /* + * Digest the modified header. + */ + header_r.base = (unsigned char *)header; + header_r.length = DNS_MESSAGE_HEADERLEN; + ret = dst_context_adddata(msg->tsigctx, &header_r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest all non-TSIG records. + */ + isc_buffer_usedregion(source, &source_r); + r.base = source_r.base + DNS_MESSAGE_HEADERLEN; + if (has_tsig) { + r.length = msg->sigstart - DNS_MESSAGE_HEADERLEN; + } else { + r.length = source_r.length - DNS_MESSAGE_HEADERLEN; + } + ret = dst_context_adddata(msg->tsigctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + /* + * Digest the time signed and fudge. + */ + if (has_tsig) { + isc_buffer_init(&databuf, data, sizeof(data)); + isc_buffer_putuint48(&databuf, tsig.timesigned); + isc_buffer_putuint16(&databuf, tsig.fudge); + isc_buffer_usedregion(&databuf, &r); + ret = dst_context_adddata(msg->tsigctx, &r); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + + sig_r.base = tsig.signature; + sig_r.length = tsig.siglen; + if (tsig.siglen == 0) { + if (tsig.error != dns_rcode_noerror) { + msg->tsigstatus = tsig.error; + if (tsig.error == dns_tsigerror_badtime) { + ret = DNS_R_CLOCKSKEW; + } else { + ret = DNS_R_TSIGERRORSET; + } + } else { + tsig_log(msg->tsigkey, 2, "signature is empty"); + ret = DNS_R_TSIGVERIFYFAILURE; + } + goto cleanup_context; + } + + ret = dst_context_verify(msg->tsigctx, &sig_r); + if (ret == DST_R_VERIFYFAILURE) { + tsig_log(msg->tsigkey, 2, + "signature failed to verify(2)"); + ret = DNS_R_TSIGVERIFYFAILURE; + goto cleanup_context; + } else if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + msg->verified_sig = 1; + + /* + * Here at this point, the MAC has been verified. Even + * if any of the following code returns a TSIG error, + * the reply will be signed and WILL always include the + * request MAC in the digest computation. + */ + + /* + * Is the time ok? + */ + isc_stdtime_get(&now); + + if (now + msg->timeadjust > tsig.timesigned + tsig.fudge) { + msg->tsigstatus = dns_tsigerror_badtime; + tsig_log(msg->tsigkey, 2, "signature has expired"); + ret = DNS_R_CLOCKSKEW; + goto cleanup_context; + } else if (now + msg->timeadjust < tsig.timesigned - tsig.fudge) + { + msg->tsigstatus = dns_tsigerror_badtime; + tsig_log(msg->tsigkey, 2, "signature is in the future"); + ret = DNS_R_CLOCKSKEW; + goto cleanup_context; + } + + alg = dst_key_alg(key); + ret = dst_key_sigsize(key, &siglen); + if (ret != ISC_R_SUCCESS) { + goto cleanup_context; + } + if (dns__tsig_algvalid(alg)) { + uint16_t digestbits = dst_key_getbits(key); + + if (tsig.siglen > 0 && digestbits != 0 && + tsig.siglen < ((digestbits + 7) / 8)) + { + msg->tsigstatus = dns_tsigerror_badtrunc; + tsig_log(msg->tsigkey, 2, + "truncated signature length " + "too small"); + ret = DNS_R_TSIGVERIFYFAILURE; + goto cleanup_context; + } + if (tsig.siglen > 0 && digestbits == 0 && + tsig.siglen < siglen) + { + msg->tsigstatus = dns_tsigerror_badtrunc; + tsig_log(msg->tsigkey, 2, + "signature length too small"); + ret = DNS_R_TSIGVERIFYFAILURE; + goto cleanup_context; + } + } + + if (tsig.error != dns_rcode_noerror) { + msg->tsigstatus = tsig.error; + if (tsig.error == dns_tsigerror_badtime) { + ret = DNS_R_CLOCKSKEW; + } else { + ret = DNS_R_TSIGERRORSET; + } + goto cleanup_context; + } + } + + msg->tsigstatus = dns_rcode_noerror; + ret = ISC_R_SUCCESS; + +cleanup_context: + /* + * Except in error conditions, don't destroy the DST context + * for unsigned messages; it is a running sum till the next + * TSIG signed message. + */ + if ((ret != ISC_R_SUCCESS || has_tsig) && msg->tsigctx != NULL) { + dst_context_destroy(&msg->tsigctx); + } + +cleanup_querystruct: + dns_rdata_freestruct(&querytsig); + + return (ret); +} + +isc_result_t +dns_tsigkey_find(dns_tsigkey_t **tsigkey, const dns_name_t *name, + const dns_name_t *algorithm, dns_tsig_keyring_t *ring) { + dns_tsigkey_t *key; + isc_stdtime_t now; + isc_result_t result; + + REQUIRE(tsigkey != NULL); + REQUIRE(*tsigkey == NULL); + REQUIRE(name != NULL); + REQUIRE(ring != NULL); + + RWLOCK(&ring->lock, isc_rwlocktype_write); + cleanup_ring(ring); + RWUNLOCK(&ring->lock, isc_rwlocktype_write); + + isc_stdtime_get(&now); + RWLOCK(&ring->lock, isc_rwlocktype_read); + key = NULL; + result = dns_rbt_findname(ring->keys, name, 0, NULL, (void *)&key); + if (result == DNS_R_PARTIALMATCH || result == ISC_R_NOTFOUND) { + RWUNLOCK(&ring->lock, isc_rwlocktype_read); + return (ISC_R_NOTFOUND); + } + if (algorithm != NULL && !dns_name_equal(key->algorithm, algorithm)) { + RWUNLOCK(&ring->lock, isc_rwlocktype_read); + return (ISC_R_NOTFOUND); + } + if (key->inception != key->expire && isc_serial_lt(key->expire, now)) { + /* + * The key has expired. + */ + RWUNLOCK(&ring->lock, isc_rwlocktype_read); + RWLOCK(&ring->lock, isc_rwlocktype_write); + remove_fromring(key); + RWUNLOCK(&ring->lock, isc_rwlocktype_write); + return (ISC_R_NOTFOUND); + } +#if 0 + /* + * MPAXXX We really should look at the inception time. + */ + if (key->inception != key->expire && + isc_serial_lt(key->inception, now)) { + RWUNLOCK(&ring->lock, isc_rwlocktype_read); + adjust_lru(key); + return (ISC_R_NOTFOUND); + } +#endif /* if 0 */ + isc_refcount_increment(&key->refs); + RWUNLOCK(&ring->lock, isc_rwlocktype_read); + adjust_lru(key); + *tsigkey = key; + return (ISC_R_SUCCESS); +} + +static void +free_tsignode(void *node, void *_unused) { + dns_tsigkey_t *key; + + REQUIRE(node != NULL); + + UNUSED(_unused); + + key = node; + if (key->generated) { + if (ISC_LINK_LINKED(key, link)) { + ISC_LIST_UNLINK(key->ring->lru, key, link); + } + } + dns_tsigkey_detach(&key); +} + +isc_result_t +dns_tsigkeyring_create(isc_mem_t *mctx, dns_tsig_keyring_t **ringp) { + isc_result_t result; + dns_tsig_keyring_t *ring; + + REQUIRE(mctx != NULL); + REQUIRE(ringp != NULL); + REQUIRE(*ringp == NULL); + + ring = isc_mem_get(mctx, sizeof(dns_tsig_keyring_t)); + + isc_rwlock_init(&ring->lock, 0, 0); + ring->keys = NULL; + result = dns_rbt_create(mctx, free_tsignode, NULL, &ring->keys); + if (result != ISC_R_SUCCESS) { + isc_rwlock_destroy(&ring->lock); + isc_mem_put(mctx, ring, sizeof(dns_tsig_keyring_t)); + return (result); + } + + ring->writecount = 0; + ring->mctx = NULL; + ring->generated = 0; + ring->maxgenerated = DNS_TSIG_MAXGENERATEDKEYS; + ISC_LIST_INIT(ring->lru); + isc_mem_attach(mctx, &ring->mctx); + isc_refcount_init(&ring->references, 1); + + *ringp = ring; + return (ISC_R_SUCCESS); +} + +isc_result_t +dns_tsigkeyring_add(dns_tsig_keyring_t *ring, const dns_name_t *name, + dns_tsigkey_t *tkey) { + isc_result_t result; + + result = keyring_add(ring, name, tkey); + if (result == ISC_R_SUCCESS) { + isc_refcount_increment(&tkey->refs); + } + + return (result); +} + +void +dns_tsigkeyring_attach(dns_tsig_keyring_t *source, + dns_tsig_keyring_t **target) { + REQUIRE(source != NULL); + REQUIRE(target != NULL && *target == NULL); + + isc_refcount_increment(&source->references); + + *target = source; +} + +void +dns_tsigkeyring_detach(dns_tsig_keyring_t **ringp) { + dns_tsig_keyring_t *ring; + + REQUIRE(ringp != NULL); + REQUIRE(*ringp != NULL); + + ring = *ringp; + *ringp = NULL; + + if (isc_refcount_decrement(&ring->references) == 1) { + destroyring(ring); + } +} + +void +dns_keyring_restore(dns_tsig_keyring_t *ring, FILE *fp) { + isc_stdtime_t now; + isc_result_t result; + + isc_stdtime_get(&now); + do { + result = restore_key(ring, now, fp); + if (result == ISC_R_NOMORE) { + return; + } + if (result == DNS_R_BADALG || result == DNS_R_EXPIRED) { + result = ISC_R_SUCCESS; + } + } while (result == ISC_R_SUCCESS); +} |