diff options
Diffstat (limited to 'src/resolve/resolved-dns-dnssec.c')
| -rw-r--r-- | src/resolve/resolved-dns-dnssec.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c index 9eb54d44db..d7d50c164c 100644 --- a/src/resolve/resolved-dns-dnssec.c +++ b/src/resolve/resolved-dns-dnssec.c @@ -23,6 +23,7 @@ #include "alloc-util.h" #include "dns-domain.h" +#include "hexdecoct.h" #include "resolved-dns-dnssec.h" #include "resolved-dns-packet.h" #include "string-table.h" @@ -795,6 +796,187 @@ int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ return 0; } +int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret) { + uint8_t wire_format[DNS_WIRE_FOMAT_HOSTNAME_MAX]; + gcry_md_hd_t md = NULL; + size_t hash_size; + int algorithm; + void *result; + unsigned k; + int r; + + assert(nsec3); + assert(name); + assert(ret); + + if (nsec3->key->type != DNS_TYPE_NSEC3) + return -EINVAL; + + algorithm = digest_to_gcrypt(nsec3->nsec3.algorithm); + if (algorithm < 0) + return algorithm; + + initialize_libgcrypt(); + + hash_size = gcry_md_get_algo_dlen(algorithm); + assert(hash_size > 0); + + if (nsec3->nsec3.next_hashed_name_size != hash_size) + return -EINVAL; + + r = dns_name_to_wire_format(name, wire_format, sizeof(wire_format), true); + if (r < 0) + return r; + + gcry_md_open(&md, algorithm, 0); + if (!md) + return -EIO; + + gcry_md_write(md, wire_format, r); + gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size); + + result = gcry_md_read(md, 0); + if (!result) { + r = -EIO; + goto finish; + } + + for (k = 0; k < nsec3->nsec3.iterations; k++) { + uint8_t tmp[hash_size]; + memcpy(tmp, result, hash_size); + + gcry_md_reset(md); + gcry_md_write(md, tmp, hash_size); + gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size); + + result = gcry_md_read(md, 0); + if (!result) { + r = -EIO; + goto finish; + } + } + + memcpy(ret, result, hash_size); + r = (int) hash_size; + +finish: + gcry_md_close(md); + return r; +} + +int dnssec_test_nsec(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result) { + DnsResourceRecord *rr; + int r; + + assert(key); + assert(result); + + /* Look for any NSEC/NSEC3 RRs that say something about the specified key. */ + + DNS_ANSWER_FOREACH(rr, answer) { + + if (rr->key->class != key->class) + continue; + + switch (rr->key->type) { + + case DNS_TYPE_NSEC: + + r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), DNS_RESOURCE_KEY_NAME(key)); + if (r < 0) + return r; + if (r > 0) { + *result = bitmap_isset(rr->nsec.types, key->type) ? DNSSEC_NSEC_FOUND : DNSSEC_NSEC_NODATA; + return 0; + } + + r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), DNS_RESOURCE_KEY_NAME(key), rr->nsec.next_domain_name); + if (r < 0) + return r; + if (r > 0) { + *result = DNSSEC_NSEC_NXDOMAIN; + return 0; + } + break; + + case DNS_TYPE_NSEC3: { + _cleanup_free_ void *decoded = NULL; + size_t decoded_size; + char label[DNS_LABEL_MAX]; + uint8_t hashed[DNSSEC_HASH_SIZE_MAX]; + int label_length, c, q; + const char *p; + bool covered; + + /* RFC 5155, Section 8.2 says we MUST ignore NSEC3 RRs with flags != 0 or 1 */ + if (!IN_SET(rr->nsec3.flags, 0, 1)) + continue; + + p = DNS_RESOURCE_KEY_NAME(rr->key); + label_length = dns_label_unescape(&p, label, sizeof(label)); + if (label_length < 0) + return label_length; + if (label_length == 0) + continue; + + r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), p); + if (r < 0) + return r; + if (r == 0) + continue; + + r = unbase32hexmem(label, label_length, false, &decoded, &decoded_size); + if (r == -EINVAL) + continue; + if (r < 0) + return r; + + if (decoded_size != rr->nsec3.next_hashed_name_size) + continue; + + c = memcmp(decoded, rr->nsec3.next_hashed_name, decoded_size); + if (c == 0) + continue; + + r = dnssec_nsec3_hash(rr, DNS_RESOURCE_KEY_NAME(key), hashed); + /* RFC 5155, Section 8.1 says we MUST ignore NSEC3 RRs with unknown algorithms */ + if (r == -EOPNOTSUPP) + continue; + if (r < 0) + return r; + if ((size_t) r != decoded_size) + continue; + + r = memcmp(decoded, hashed, decoded_size); + if (r == 0) { + *result = bitmap_isset(rr->nsec3.types, key->type) ? DNSSEC_NSEC_FOUND : DNSSEC_NSEC_NODATA; + return 0; + } + + q = memcmp(hashed, rr->nsec3.next_hashed_name, decoded_size); + + covered = c < 0 ? + r < 0 && q < 0 : + q < 0 || r < 0; + + if (covered) { + *result = DNSSEC_NSEC_NXDOMAIN; + return 0; + } + + break; + } + + default: + break; + } + } + + /* No approproate NSEC RR found, report this. */ + *result = DNSSEC_NSEC_NO_RR; + return 0; +} + static const char* const dnssec_mode_table[_DNSSEC_MODE_MAX] = { [DNSSEC_NO] = "no", [DNSSEC_TRUST] = "trust", @@ -811,5 +993,6 @@ static const char* const dnssec_result_table[_DNSSEC_RESULT_MAX] = { [DNSSEC_MISSING_KEY] = "missing-key", [DNSSEC_UNSIGNED] = "unsigned", [DNSSEC_FAILED_AUXILIARY] = "failed-auxiliary", + [DNSSEC_NSEC_MISMATCH] = "nsec-mismatch", }; DEFINE_STRING_TABLE_LOOKUP(dnssec_result, DnssecResult); |