diff options
| author | Lennart Poettering <lennart@poettering.net> | 2015-12-21 20:00:34 +0100 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2015-12-26 19:09:10 +0100 |
| commit | 13b78323bad1e41e0474b833da2a0b72aab56f09 (patch) | |
| tree | b6ea500391cf2f41aa5fe3f66624afc8621524c0 | |
| parent | e7ff0e0b391341bdc4d9c08dff1c477e1df6a682 (diff) | |
resolved: when doing NSEC3 proof, first find right NSEC3 suffix
When doing an NSEC3 proof, before detrmining whether a name is the
closest encloser we first need to figure out the longest common suffix
we have with any NSEC3 RR in the reply.
| -rw-r--r-- | src/resolve/resolved-dns-dnssec.c | 47 |
1 files changed, 41 insertions, 6 deletions
diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c index 9ddad38fa6..dbda71b03d 100644 --- a/src/resolve/resolved-dns-dnssec.c +++ b/src/resolve/resolved-dns-dnssec.c @@ -912,7 +912,7 @@ finish: static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result) { _cleanup_free_ char *next_closer_domain = NULL, *l = NULL; uint8_t hashed[DNSSEC_HASH_SIZE_MAX]; - const char *p, *pp = NULL; + const char *suffix, *p, *pp = NULL; DnsResourceRecord *rr; DnsAnswerFlags flags; int hashed_size, r; @@ -920,7 +920,42 @@ static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecR assert(key); assert(result); - /* First step, look for the closest encloser NSEC3 RR in 'answer' that matches 'key' */ + /* First step, look for the longest common suffix we find with any NSEC3 RR in the response. */ + suffix = DNS_RESOURCE_KEY_NAME(key); + for (;;) { + DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { + _cleanup_free_ char *hashed_domain = NULL, *label = NULL; + + if ((flags & DNS_ANSWER_AUTHENTICATED) == 0) + continue; + + if (rr->key->type != DNS_TYPE_NSEC3) + continue; + + /* 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; + + r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rr->key), suffix); + if (r < 0) + return r; + if (r > 0) + goto found_suffix; + } + + /* Strip one label from the front */ + r = dns_name_parent(&suffix); + if (r < 0) + return r; + if (r == 0) + break; + } + + *result = DNSSEC_NSEC_NO_RR; + return 0; + +found_suffix: + /* Second step, find the closest encloser NSEC3 RR in 'answer' that matches 'key' */ p = DNS_RESOURCE_KEY_NAME(key); for (;;) { DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { @@ -936,7 +971,7 @@ static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecR if (!IN_SET(rr->nsec3.flags, 0, 1)) continue; - r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rr->key), p); + r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rr->key), suffix); if (r < 0) return r; if (r == 0) @@ -956,7 +991,7 @@ static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecR if (!label) return -ENOMEM; - hashed_domain = strjoin(label, ".", p, NULL); + hashed_domain = strjoin(label, ".", suffix, NULL); if (!hashed_domain) return -ENOMEM; @@ -964,7 +999,7 @@ static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecR if (r < 0) return r; if (r > 0) - goto found; + goto found_closest_encloser; } /* We didn't find the closest encloser with this name, @@ -984,7 +1019,7 @@ static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecR *result = DNSSEC_NSEC_NO_RR; return 0; -found: +found_closest_encloser: /* We found a closest encloser in 'p'; next closer is 'pp' */ /* Ensure this is not a DNAME domain, see RFC5155, section 8.3. */ |