diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/resolve/RFCs | 18 | ||||
| -rw-r--r-- | src/resolve/dns-type.c | 11 | ||||
| -rw-r--r-- | src/resolve/dns-type.h | 1 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-answer.c | 37 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-answer.h | 2 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-cache.c | 13 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-dnssec.c | 507 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-dnssec.h | 4 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-packet.c | 112 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-query.c | 4 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-rr.c | 123 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-rr.h | 19 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-server.c | 146 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-server.h | 15 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 114 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-trust-anchor.c | 2 | ||||
| -rw-r--r-- | src/resolve/resolved-link.c | 16 | ||||
| -rw-r--r-- | src/resolve/test-dnssec-complex.c | 146 | ||||
| -rw-r--r-- | src/resolve/test-dnssec.c | 4 | ||||
| -rw-r--r-- | src/shared/dns-domain.c | 99 | ||||
| -rw-r--r-- | src/shared/dns-domain.h | 3 | ||||
| -rw-r--r-- | src/test/test-dns-domain.c | 21 |
22 files changed, 1189 insertions, 228 deletions
diff --git a/src/resolve/RFCs b/src/resolve/RFCs index 33f4dd9cb6..22004a00cd 100644 --- a/src/resolve/RFCs +++ b/src/resolve/RFCs @@ -13,14 +13,14 @@ Y https://tools.ietf.org/html/rfc1123 → Requirements for Internet Hosts -- App Y https://tools.ietf.org/html/rfc1536 → Common DNS Implementation Errors and Suggested Fixes Y https://tools.ietf.org/html/rfc1876 → A Means for Expressing Location Information in the Domain Name System Y https://tools.ietf.org/html/rfc2181 → Clarifications to the DNS Specification - https://tools.ietf.org/html/rfc2308 → Negative Caching of DNS Queries (DNS NCACHE) +Y https://tools.ietf.org/html/rfc2308 → Negative Caching of DNS Queries (DNS NCACHE) Y https://tools.ietf.org/html/rfc2782 → A DNS RR for specifying the location of services (DNS SRV) D https://tools.ietf.org/html/rfc3492 → Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA) Y https://tools.ietf.org/html/rfc3596 → DNS Extensions to Support IP Version 6 Y https://tools.ietf.org/html/rfc3597 → Handling of Unknown DNS Resource Record (RR) Types - https://tools.ietf.org/html/rfc4033 → DNS Security Introduction and Requirements - https://tools.ietf.org/html/rfc4034 → Resource Records for the DNS Security Extensions - https://tools.ietf.org/html/rfc4035 → Protocol Modifications for the DNS Security Extensions +Y https://tools.ietf.org/html/rfc4033 → DNS Security Introduction and Requirements +Y https://tools.ietf.org/html/rfc4034 → Resource Records for the DNS Security Extensions +Y https://tools.ietf.org/html/rfc4035 → Protocol Modifications for the DNS Security Extensions ! https://tools.ietf.org/html/rfc4183 → A Suggested Scheme for DNS Resolution of Networks and Gateways Y https://tools.ietf.org/html/rfc4255 → Using DNS to Securely Publish Secure Shell (SSH) Key Fingerprints Y https://tools.ietf.org/html/rfc4343 → Domain Name System (DNS) Case Insensitivity Clarification @@ -31,26 +31,26 @@ Y https://tools.ietf.org/html/rfc4509 → Use of SHA-256 in DNSSEC Delegation Si ~ https://tools.ietf.org/html/rfc4697 → Observed DNS Resolution Misbehavior Y https://tools.ietf.org/html/rfc4795 → Link-Local Multicast Name Resolution (LLMNR) Y https://tools.ietf.org/html/rfc5011 → Automated Updates of DNS Security (DNSSEC) Trust Anchors - https://tools.ietf.org/html/rfc5155 → DNS Security (DNSSEC) Hashed Authenticated Denial of Existence +Y https://tools.ietf.org/html/rfc5155 → DNS Security (DNSSEC) Hashed Authenticated Denial of Existence Y https://tools.ietf.org/html/rfc5452 → Measures for Making DNS More Resilient against Forged Answers Y https://tools.ietf.org/html/rfc5702 → Use of SHA-2 Algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC Y https://tools.ietf.org/html/rfc5890 → Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework Y https://tools.ietf.org/html/rfc5891 → Internationalized Domain Names in Applications (IDNA): Protocol Y https://tools.ietf.org/html/rfc5966 → DNS Transport over TCP - Implementation Requirements Y https://tools.ietf.org/html/rfc6303 → Locally Served DNS Zones - https://tools.ietf.org/html/rfc6604 → xNAME RCODE and Status Bits Clarification +Y https://tools.ietf.org/html/rfc6604 → xNAME RCODE and Status Bits Clarification Y https://tools.ietf.org/html/rfc6605 → Elliptic Curve Digital Signature Algorithm (DSA) for DNSSEC https://tools.ietf.org/html/rfc6672 → DNAME Redirection in the DNS ! https://tools.ietf.org/html/rfc6731 → Improved Recursive DNS Server Selection for Multi-Interfaced Nodes Y https://tools.ietf.org/html/rfc6761 → Special-Use Domain Names https://tools.ietf.org/html/rfc6762 → Multicast DNS https://tools.ietf.org/html/rfc6763 → DNS-Based Service Discovery - https://tools.ietf.org/html/rfc6781 → DNSSEC Operational Practices, Version 2 - https://tools.ietf.org/html/rfc6840 → Clarifications and Implementation Notes for DNS Security (DNSSEC) +~ https://tools.ietf.org/html/rfc6781 → DNSSEC Operational Practices, Version 2 +Y https://tools.ietf.org/html/rfc6840 → Clarifications and Implementation Notes for DNS Security (DNSSEC) Y https://tools.ietf.org/html/rfc6891 → Extension Mechanisms for DNS (EDNS(0)) Y https://tools.ietf.org/html/rfc6944 → Applicability Statement: DNS Security (DNSSEC) DNSKEY Algorithm Implementation Status Y https://tools.ietf.org/html/rfc6975 → Signaling Cryptographic Algorithm Understanding in DNS Security Extensions (DNSSEC) - https://tools.ietf.org/html/rfc7129 → Authenticated Denial of Existence in the DNS +Y https://tools.ietf.org/html/rfc7129 → Authenticated Denial of Existence in the DNS Y https://tools.ietf.org/html/rfc7646 → Definition and Use of DNSSEC Negative Trust Anchors ~ https://tools.ietf.org/html/rfc7719 → DNS Terminology diff --git a/src/resolve/dns-type.c b/src/resolve/dns-type.c index 47a37fa0a7..058d14009a 100644 --- a/src/resolve/dns-type.c +++ b/src/resolve/dns-type.c @@ -135,6 +135,17 @@ bool dns_type_may_wildcard(uint16_t type) { DNS_TYPE_DNAME); } +bool dns_type_apex_only(uint16_t type) { + + /* Returns true for all RR types that may only appear signed in a zone apex */ + + return IN_SET(type, + DNS_TYPE_SOA, + DNS_TYPE_NS, /* this one can appear elsewhere, too, but not signed */ + DNS_TYPE_DNSKEY, + DNS_TYPE_NSEC3PARAM); +} + bool dns_type_is_dnssec(uint16_t type) { return IN_SET(type, DNS_TYPE_DS, diff --git a/src/resolve/dns-type.h b/src/resolve/dns-type.h index 747bc854e1..78ff71b06e 100644 --- a/src/resolve/dns-type.h +++ b/src/resolve/dns-type.h @@ -132,6 +132,7 @@ bool dns_type_may_redirect(uint16_t type); bool dns_type_is_dnssec(uint16_t type); bool dns_type_is_obsolete(uint16_t type); bool dns_type_may_wildcard(uint16_t type); +bool dns_type_apex_only(uint16_t type); bool dns_class_is_pseudo(uint16_t class); bool dns_class_is_valid_rr(uint16_t class); diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c index c359432a7a..f74e440531 100644 --- a/src/resolve/resolved-dns-answer.c +++ b/src/resolve/resolved-dns-answer.c @@ -821,3 +821,40 @@ void dns_answer_dump(DnsAnswer *answer, FILE *f) { fputc('\n', f); } } + +bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname) { + DnsResourceRecord *rr; + int r; + + assert(cname); + + /* Checks whether the answer contains a DNAME record that indicates that the specified CNAME record is + * synthesized from it */ + + if (cname->key->type != DNS_TYPE_CNAME) + return 0; + + DNS_ANSWER_FOREACH(rr, a) { + _cleanup_free_ char *n = NULL; + + if (rr->key->type != DNS_TYPE_DNAME) + continue; + if (rr->key->class != cname->key->class) + continue; + + r = dns_name_change_suffix(cname->cname.name, rr->dname.name, DNS_RESOURCE_KEY_NAME(rr->key), &n); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dns_name_equal(n, DNS_RESOURCE_KEY_NAME(cname->key)); + if (r < 0) + return r; + if (r > 0) + return 1; + + } + + return 0; +} diff --git a/src/resolve/resolved-dns-answer.h b/src/resolve/resolved-dns-answer.h index 3eff21f8d0..1875fd6136 100644 --- a/src/resolve/resolved-dns-answer.h +++ b/src/resolve/resolved-dns-answer.h @@ -83,6 +83,8 @@ int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr); int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags); int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags); +bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname); + static inline unsigned dns_answer_size(DnsAnswer *a) { return a ? a->n_rrs : 0; } diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c index 301f383809..fdb34d11df 100644 --- a/src/resolve/resolved-dns-cache.c +++ b/src/resolve/resolved-dns-cache.c @@ -247,6 +247,19 @@ static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) { first = hashmap_get(c->by_key, i->key); if (first) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL; + + /* Keep a reference to the original key, while we manipulate the list. */ + k = dns_resource_key_ref(first->key); + + /* Now, try to reduce the number of keys we keep */ + dns_resource_key_reduce(&first->key, &i->key); + + if (first->rr) + dns_resource_key_reduce(&first->rr->key, &i->key); + if (i->rr) + dns_resource_key_reduce(&i->rr->key, &i->key); + LIST_PREPEND(by_key, first, i); assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); } else { diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c index afff979b5a..f999a8cc77 100644 --- a/src/resolve/resolved-dns-dnssec.c +++ b/src/resolve/resolved-dns-dnssec.c @@ -35,17 +35,15 @@ * * TODO: * - * - wildcard zones compatibility (NSEC/NSEC3 wildcard check is missing) - * - multi-label zone compatibility - * - cname/dname compatibility - * - nxdomain on qname * - bus calls to override DNSEC setting per interface * - log all DNSSEC downgrades + * - log all RRs that failed validation * - enable by default - * - * - RFC 4035, Section 5.3.4 (When receiving a positive wildcard reply, use NSEC to ensure it actually really applies) - * - RFC 6840, Section 4.1 (ensure we don't get fed a glue NSEC from the parent zone) - * - RFC 6840, Section 4.3 (check for CNAME on NSEC too) + * - Allow clients to request DNSSEC even if DNSSEC is off + * - make sure when getting an NXDOMAIN response through CNAME, we still process the first CNAMEs in the packet + * - update test-complex to also do ResolveAddress lookups + * - extend complex test to check "xn--kprw13d." DNAME domain + * - rework IDNA stuff: only to IDNA for ResolveAddress and ResolveService, and prepare a pair of lookup keys then, never do IDNA comparisons after that * */ #define VERIFY_RRS_MAX 256 @@ -430,6 +428,57 @@ static void md_add_uint32(gcry_md_hd_t md, uint32_t v) { gcry_md_write(md, &v, sizeof(v)); } +static int dnssec_rrsig_prepare(DnsResourceRecord *rrsig) { + int n_key_labels, n_signer_labels; + const char *name; + int r; + + /* Checks whether the specified RRSIG RR is somewhat valid, and initializes the .n_skip_labels_source and + * .n_skip_labels_signer fields so that we can use them later on. */ + + assert(rrsig); + assert(rrsig->key->type == DNS_TYPE_RRSIG); + + /* Check if this RRSIG RR is already prepared */ + if (rrsig->n_skip_labels_source != (unsigned) -1) + return 0; + + if (rrsig->rrsig.inception > rrsig->rrsig.expiration) + return -EINVAL; + + name = DNS_RESOURCE_KEY_NAME(rrsig->key); + + n_key_labels = dns_name_count_labels(name); + if (n_key_labels < 0) + return n_key_labels; + if (rrsig->rrsig.labels > n_key_labels) + return -EINVAL; + + n_signer_labels = dns_name_count_labels(rrsig->rrsig.signer); + if (n_signer_labels < 0) + return n_signer_labels; + if (n_signer_labels > rrsig->rrsig.labels) + return -EINVAL; + + r = dns_name_skip(name, n_key_labels - n_signer_labels, &name); + if (r < 0) + return r; + if (r == 0) + return -EINVAL; + + /* Check if the signer is really a suffix of us */ + r = dns_name_equal(name, rrsig->rrsig.signer); + if (r < 0) + return r; + if (r == 0) + return -EINVAL; + + rrsig->n_skip_labels_source = n_key_labels - rrsig->rrsig.labels; + rrsig->n_skip_labels_signer = n_key_labels - n_signer_labels; + + return 0; +} + static int dnssec_rrsig_expired(DnsResourceRecord *rrsig, usec_t realtime) { usec_t expiration, inception, skew; @@ -499,6 +548,35 @@ static int algorithm_to_gcrypt_md(uint8_t algorithm) { } } +static void dnssec_fix_rrset_ttl( + DnsResourceRecord *list[], + unsigned n, + DnsResourceRecord *rrsig, + usec_t realtime) { + + unsigned k; + + assert(list); + assert(n > 0); + assert(rrsig); + + for (k = 0; k < n; k++) { + DnsResourceRecord *rr = list[k]; + + /* Pick the TTL as the minimum of the RR's TTL, the + * RR's original TTL according to the RRSIG and the + * RRSIG's own TTL, see RFC 4035, Section 5.3.3 */ + rr->ttl = MIN3(rr->ttl, rrsig->rrsig.original_ttl, rrsig->ttl); + rr->expiry = rrsig->rrsig.expiration * USEC_PER_SEC; + + /* Copy over information about the signer and wildcard source of synthesis */ + rr->n_skip_labels_source = rrsig->n_skip_labels_source; + rr->n_skip_labels_signer = rrsig->n_skip_labels_signer; + } + + rrsig->expiry = rrsig->rrsig.expiration * USEC_PER_SEC; +} + int dnssec_verify_rrset( DnsAnswer *a, const DnsResourceKey *key, @@ -508,14 +586,14 @@ int dnssec_verify_rrset( DnssecResult *result) { uint8_t wire_format_name[DNS_WIRE_FOMAT_HOSTNAME_MAX]; - size_t hash_size; - void *hash; DnsResourceRecord **list, *rr; + const char *source, *name; gcry_md_hd_t md = NULL; int r, md_algorithm; size_t k, n = 0; + size_t hash_size; + void *hash; bool wildcard; - const char *source; assert(key); assert(rrsig); @@ -536,6 +614,14 @@ int dnssec_verify_rrset( if (md_algorithm < 0) return md_algorithm; + r = dnssec_rrsig_prepare(rrsig); + if (r == -EINVAL) { + *result = DNSSEC_INVALID; + return r; + } + if (r < 0) + return r; + r = dnssec_rrsig_expired(rrsig, realtime); if (r < 0) return r; @@ -544,8 +630,32 @@ int dnssec_verify_rrset( return 0; } + name = DNS_RESOURCE_KEY_NAME(key); + + /* Some keys may only appear signed in the zone apex, and are invalid anywhere else. (SOA, NS...) */ + if (dns_type_apex_only(rrsig->rrsig.type_covered)) { + r = dns_name_equal(rrsig->rrsig.signer, name); + if (r < 0) + return r; + if (r == 0) { + *result = DNSSEC_INVALID; + return 0; + } + } + + /* OTOH DS RRs may not appear in the zone apex, but are valid everywhere else. */ + if (rrsig->rrsig.type_covered == DNS_TYPE_DS) { + r = dns_name_equal(rrsig->rrsig.signer, name); + if (r < 0) + return r; + if (r > 0) { + *result = DNSSEC_INVALID; + return 0; + } + } + /* Determine the "Source of Synthesis" and whether this is a wildcard RRSIG */ - r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(key), rrsig->rrsig.labels, &source); + r = dns_name_suffix(name, rrsig->rrsig.labels, &source); if (r < 0) return r; if (r > 0 && !dns_type_may_wildcard(rrsig->rrsig.type_covered)) { @@ -556,11 +666,11 @@ int dnssec_verify_rrset( if (r == 1) { /* If we stripped a single label, then let's see if that maybe was "*". If so, we are not really * synthesized from a wildcard, we are the wildcard itself. Treat that like a normal name. */ - r = dns_name_startswith(DNS_RESOURCE_KEY_NAME(key), "*"); + r = dns_name_startswith(name, "*"); if (r < 0) return r; if (r > 0) - source = DNS_RESOURCE_KEY_NAME(key); + source = name; wildcard = r == 0; } else @@ -675,12 +785,17 @@ int dnssec_verify_rrset( if (r < 0) goto finish; - if (!r) + /* Now, fix the ttl, expiry, and remember the synthesizing source and the signer */ + if (r > 0) + dnssec_fix_rrset_ttl(list, n, rrsig, realtime); + + if (r == 0) *result = DNSSEC_INVALID; else if (wildcard) *result = DNSSEC_VALIDATED_WILDCARD; else *result = DNSSEC_VALIDATED; + r = 0; finish: @@ -719,8 +834,6 @@ int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnske } int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig) { - int r; - assert(key); assert(rrsig); @@ -733,45 +846,9 @@ int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig) if (rrsig->rrsig.type_covered != key->type) return 0; - /* Make sure signer is a parent of the RRset */ - r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rrsig->key), rrsig->rrsig.signer); - if (r <= 0) - return r; - - /* Make sure the owner name has at least as many labels as the "label" fields indicates. */ - r = dns_name_count_labels(DNS_RESOURCE_KEY_NAME(rrsig->key)); - if (r < 0) - return r; - if (r < rrsig->rrsig.labels) - return 0; - return dns_name_equal(DNS_RESOURCE_KEY_NAME(rrsig->key), DNS_RESOURCE_KEY_NAME(key)); } -static int dnssec_fix_rrset_ttl(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord *rrsig, usec_t realtime) { - DnsResourceRecord *rr; - int r; - - assert(key); - assert(rrsig); - - DNS_ANSWER_FOREACH(rr, a) { - r = dns_resource_key_equal(key, rr->key); - if (r < 0) - return r; - if (r == 0) - continue; - - /* Pick the TTL as the minimum of the RR's TTL, the - * RR's original TTL according to the RRSIG and the - * RRSIG's own TTL, see RFC 4035, Section 5.3.3 */ - rr->ttl = MIN3(rr->ttl, rrsig->rrsig.original_ttl, rrsig->ttl); - rr->expiry = rrsig->rrsig.expiration * USEC_PER_SEC; - } - - return 0; -} - int dnssec_verify_rrset_search( DnsAnswer *a, const DnsResourceKey *key, @@ -841,10 +918,6 @@ int dnssec_verify_rrset_search( case DNSSEC_VALIDATED_WILDCARD: /* Yay, the RR has been validated, * return immediately, but fix up the expiry */ - r = dnssec_fix_rrset_ttl(a, key, rrsig, realtime); - if (r < 0) - return r; - if (ret_rrsig) *ret_rrsig = rrsig; @@ -995,7 +1068,7 @@ static int digest_to_gcrypt_md(uint8_t algorithm) { } } -int dnssec_verify_dnskey(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke) { +int dnssec_verify_dnskey_by_ds(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke) { char owner_name[DNSSEC_CANONICAL_HOSTNAME_MAX]; gcry_md_hd_t md = NULL; size_t hash_size; @@ -1065,7 +1138,7 @@ finish: return r; } -int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds) { +int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds) { DnsResourceRecord *ds; DnsAnswerFlags flags; int r; @@ -1082,7 +1155,6 @@ int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ if (ds->key->type != DNS_TYPE_DS) continue; - if (ds->key->class != dnskey->key->class) continue; @@ -1092,9 +1164,9 @@ int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ if (r == 0) continue; - r = dnssec_verify_dnskey(dnskey, ds, false); - if (r == -EKEYREJECTED) - return 0; /* The DNSKEY is revoked or otherwise invalid, we won't bless it */ + r = dnssec_verify_dnskey_by_ds(dnskey, ds, false); + if (IN_SET(r, -EKEYREJECTED, -EOPNOTSUPP)) + return 0; /* The DNSKEY is revoked or otherwise invalid, or we don't support the digest algorithm */ if (r < 0) return r; if (r > 0) @@ -1211,6 +1283,13 @@ static int nsec3_is_good(DnsResourceRecord *rr, DnsResourceRecord *nsec3) { if (rr->nsec3.iterations > NSEC3_ITERATIONS_MAX) return 0; + /* Ignore NSEC3 RRs generated from wildcards */ + if (rr->n_skip_labels_source != 0) + return 0; + /* Ignore NSEC3 RRs that are located anywhere else than one label below the zone */ + if (rr->n_skip_labels_signer != 1) + return 0; + if (!nsec3) return 1; @@ -1244,6 +1323,7 @@ static int nsec3_is_good(DnsResourceRecord *rr, DnsResourceRecord *nsec3) { if (r == 0) return 0; + /* Make sure both have the same parent */ return dns_name_equal(a, b); } @@ -1535,10 +1615,158 @@ found_closest_encloser: return 0; } +static int dnssec_nsec_wildcard_equal(DnsResourceRecord *rr, const char *name) { + char label[DNS_LABEL_MAX]; + const char *n; + int r; + + assert(rr); + assert(rr->key->type == DNS_TYPE_NSEC); + + /* Checks whether the specified RR has a name beginning in "*.", and if the rest is a suffix of our name */ + + if (rr->n_skip_labels_source != 1) + return 0; + + n = DNS_RESOURCE_KEY_NAME(rr->key); + r = dns_label_unescape(&n, label, sizeof(label)); + if (r <= 0) + return r; + if (r != 1 || label[0] != '*') + return 0; + + return dns_name_endswith(name, n); +} + +static int dnssec_nsec_in_path(DnsResourceRecord *rr, const char *name) { + const char *nn, *common_suffix; + int r; + + assert(rr); + assert(rr->key->type == DNS_TYPE_NSEC); + + /* Checks whether the specified nsec RR indicates that name is an empty non-terminal (ENT) + * + * A couple of examples: + * + * NSEC bar → waldo.foo.bar: indicates that foo.bar exists and is an ENT + * NSEC waldo.foo.bar → yyy.zzz.xoo.bar: indicates that xoo.bar and zzz.xoo.bar exist and are ENTs + * NSEC yyy.zzz.xoo.bar → bar: indicates pretty much nothing about ENTs + */ + + /* First, determine parent of next domain. */ + nn = rr->nsec.next_domain_name; + r = dns_name_parent(&nn); + if (r <= 0) + return r; + + /* If the name we just determined is not equal or child of the name we are interested in, then we can't say + * anything at all. */ + r = dns_name_endswith(nn, name); + if (r <= 0) + return r; + + /* If the name we we are interested in is not a prefix of the common suffix of the NSEC RR's owner and next domain names, then we can't say anything either. */ + r = dns_name_common_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rr->nsec.next_domain_name, &common_suffix); + if (r < 0) + return r; + + return dns_name_endswith(name, common_suffix); +} + +static int dnssec_nsec_from_parent_zone(DnsResourceRecord *rr, const char *name) { + int r; + + assert(rr); + assert(rr->key->type == DNS_TYPE_NSEC); + + /* Checks whether this NSEC originates to the parent zone or the child zone. */ + + r = dns_name_parent(&name); + if (r <= 0) + return r; + + r = dns_name_equal(name, DNS_RESOURCE_KEY_NAME(rr->key)); + if (r <= 0) + return r; + + /* DNAME, and NS without SOA is an indication for a delegation. */ + if (bitmap_isset(rr->nsec.types, DNS_TYPE_DNAME)) + return 1; + + if (bitmap_isset(rr->nsec.types, DNS_TYPE_NS) && !bitmap_isset(rr->nsec.types, DNS_TYPE_SOA)) + return 1; + + return 0; +} + +static int dnssec_nsec_covers(DnsResourceRecord *rr, const char *name) { + const char *common_suffix, *p; + int r; + + assert(rr); + assert(rr->key->type == DNS_TYPE_NSEC); + + /* Checks whether the "Next Closer" is witin the space covered by the specified RR. */ + + r = dns_name_common_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rr->nsec.next_domain_name, &common_suffix); + if (r < 0) + return r; + + for (;;) { + p = name; + r = dns_name_parent(&name); + if (r < 0) + return r; + if (r == 0) + return 0; + + r = dns_name_equal(name, common_suffix); + if (r < 0) + return r; + if (r > 0) + break; + } + + /* p is now the "Next Closer". */ + + return dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), p, rr->nsec.next_domain_name); +} + +static int dnssec_nsec_covers_wildcard(DnsResourceRecord *rr, const char *name) { + const char *common_suffix, *wc; + int r; + + assert(rr); + assert(rr->key->type == DNS_TYPE_NSEC); + + /* Checks whether the "Wildcard at the Closest Encloser" is within the space covered by the specified + * RR. Specifically, checks whether 'name' has the common suffix of the NSEC RR's owner and next names as + * suffix, and whether the NSEC covers the name generated by that suffix prepended with an asterisk label. + * + * NSEC bar → waldo.foo.bar: indicates that *.bar and *.foo.bar do not exist + * NSEC waldo.foo.bar → yyy.zzz.xoo.bar: indicates that *.xoo.bar and *.zzz.xoo.bar do not exist (and more ...) + * NSEC yyy.zzz.xoo.bar → bar: indicates that a number of wildcards don#t exist either... + */ + + r = dns_name_common_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rr->nsec.next_domain_name, &common_suffix); + if (r < 0) + return r; + + /* If the common suffix is not shared by the name we are interested in, it has nothing to say for us. */ + r = dns_name_endswith(name, common_suffix); + if (r <= 0) + return r; + + wc = strjoina("*.", common_suffix, NULL); + return dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), wc, rr->nsec.next_domain_name); +} + int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) { - DnsResourceRecord *rr; - bool have_nsec3 = false; + bool have_nsec3 = false, covering_rr_authenticated = false, wildcard_rr_authenticated = false; + DnsResourceRecord *rr, *covering_rr = NULL, *wildcard_rr = NULL; DnsAnswerFlags flags; + const char *name; int r; assert(key); @@ -1546,53 +1774,117 @@ int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *r /* Look for any NSEC/NSEC3 RRs that say something about the specified key. */ + name = DNS_RESOURCE_KEY_NAME(key); + DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { if (rr->key->class != key->class) continue; - switch (rr->key->type) { + have_nsec3 = have_nsec3 || (rr->key->type == DNS_TYPE_NSEC3); - case DNS_TYPE_NSEC: + if (rr->key->type != DNS_TYPE_NSEC) + continue; - r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), DNS_RESOURCE_KEY_NAME(key)); + /* The following checks only make sense for NSEC RRs that are not expanded from a wildcard */ + r = dns_resource_record_is_synthetic(rr); + if (r < 0) + return r; + if (r > 0) + continue; + + /* Check if this is a direct match. If so, we have encountered a NODATA case */ + r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), name); + if (r < 0) + return r; + if (r == 0) { + /* If it's not a direct match, maybe it's a wild card match? */ + r = dnssec_nsec_wildcard_equal(rr, name); if (r < 0) return r; - if (r > 0) { - if (bitmap_isset(rr->nsec.types, key->type)) - *result = DNSSEC_NSEC_FOUND; - else if (bitmap_isset(rr->nsec.types, DNS_TYPE_CNAME)) - *result = DNSSEC_NSEC_CNAME; - else - *result = DNSSEC_NSEC_NODATA; - - if (authenticated) - *authenticated = flags & DNS_ANSWER_AUTHENTICATED; - if (ttl) - *ttl = rr->ttl; - - return 0; + } + if (r > 0) { + if (key->type == DNS_TYPE_DS) { + /* If we look for a DS RR and the server sent us the NSEC RR of the child zone + * we have a problem. For DS RRs we want the NSEC RR from the parent */ + if (bitmap_isset(rr->nsec.types, DNS_TYPE_SOA)) + continue; + } else { + /* For all RR types, ensure that if NS is set SOA is set too, so that we know + * we got the child's NSEC. */ + if (bitmap_isset(rr->nsec.types, DNS_TYPE_NS) && + !bitmap_isset(rr->nsec.types, DNS_TYPE_SOA)) + continue; } - 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; + if (bitmap_isset(rr->nsec.types, key->type)) + *result = DNSSEC_NSEC_FOUND; + else if (bitmap_isset(rr->nsec.types, DNS_TYPE_CNAME)) + *result = DNSSEC_NSEC_CNAME; + else + *result = DNSSEC_NSEC_NODATA; - if (authenticated) - *authenticated = flags & DNS_ANSWER_AUTHENTICATED; - if (ttl) - *ttl = rr->ttl; + if (authenticated) + *authenticated = flags & DNS_ANSWER_AUTHENTICATED; + if (ttl) + *ttl = rr->ttl; - return 0; - } - break; + return 0; + } - case DNS_TYPE_NSEC3: - have_nsec3 = true; - break; + /* Check if the name we are looking for is an empty non-terminal within the owner or next name + * of the NSEC RR. */ + r = dnssec_nsec_in_path(rr, name); + if (r < 0) + return r; + if (r > 0) { + *result = DNSSEC_NSEC_NODATA; + + if (authenticated) + *authenticated = flags & DNS_ANSWER_AUTHENTICATED; + if (ttl) + *ttl = rr->ttl; + + return 0; } + + /* The following two "covering" checks, are not useful if the NSEC is from the parent */ + r = dnssec_nsec_from_parent_zone(rr, name); + if (r < 0) + return r; + if (r > 0) + continue; + + /* Check if this NSEC RR proves the absence of an explicit RR under this name */ + r = dnssec_nsec_covers(rr, name); + if (r < 0) + return r; + if (r > 0 && (!covering_rr || !covering_rr_authenticated)) { + covering_rr = rr; + covering_rr_authenticated = flags & DNS_ANSWER_AUTHENTICATED; + } + + /* Check if this NSEC RR proves the absence of a wildcard RR under this name */ + r = dnssec_nsec_covers_wildcard(rr, name); + if (r < 0) + return r; + if (r > 0 && (!wildcard_rr || !wildcard_rr_authenticated)) { + wildcard_rr = rr; + wildcard_rr_authenticated = flags & DNS_ANSWER_AUTHENTICATED; + } + } + + if (covering_rr && wildcard_rr) { + /* If we could prove that neither the name itself, nor the wildcard at the closest encloser exists, we + * proved the NXDOMAIN case. */ + *result = DNSSEC_NSEC_NXDOMAIN; + + if (authenticated) + *authenticated = covering_rr_authenticated && wildcard_rr_authenticated; + if (ttl) + *ttl = MIN(covering_rr->ttl, wildcard_rr->ttl); + + return 0; } /* OK, this was not sufficient. Let's see if NSEC3 can help. */ @@ -1621,15 +1913,17 @@ int dnssec_nsec_test_enclosed(DnsAnswer *answer, uint16_t type, const char *name if (rr->key->type != type && type != DNS_TYPE_ANY) continue; - r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rr->key), zone); - if (r < 0) - return r; - if (r == 0) - continue; - switch (rr->key->type) { case DNS_TYPE_NSEC: + + /* We only care for NSEC RRs from the indicated zone */ + r = dns_resource_record_is_signer(rr, zone); + if (r < 0) + return r; + if (r == 0) + continue; + r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), name, rr->nsec.next_domain_name); if (r < 0) return r; @@ -1640,6 +1934,13 @@ int dnssec_nsec_test_enclosed(DnsAnswer *answer, uint16_t type, const char *name case DNS_TYPE_NSEC3: { _cleanup_free_ char *hashed_domain = NULL, *next_hashed_domain = NULL; + /* We only care for NSEC3 RRs from the indicated zone */ + r = dns_resource_record_is_signer(rr, zone); + if (r < 0) + return r; + if (r == 0) + continue; + r = nsec3_is_good(rr, NULL); if (r < 0) return r; diff --git a/src/resolve/resolved-dns-dnssec.h b/src/resolve/resolved-dns-dnssec.h index b9d32db120..955017e8cb 100644 --- a/src/resolve/resolved-dns-dnssec.h +++ b/src/resolve/resolved-dns-dnssec.h @@ -61,8 +61,8 @@ int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig); int dnssec_verify_rrset(DnsAnswer *answer, const DnsResourceKey *key, DnsResourceRecord *rrsig, DnsResourceRecord *dnskey, usec_t realtime, DnssecResult *result); int dnssec_verify_rrset_search(DnsAnswer *answer, const DnsResourceKey *key, DnsAnswer *validated_dnskeys, usec_t realtime, DnssecResult *result, DnsResourceRecord **rrsig); -int dnssec_verify_dnskey(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke); -int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds); +int dnssec_verify_dnskey_by_ds(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke); +int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds); int dnssec_has_rrsig(DnsAnswer *a, const DnsResourceKey *key); diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c index a8a8632491..0acbcfe261 100644 --- a/src/resolve/resolved-dns-packet.c +++ b/src/resolve/resolved-dns-packet.c @@ -2017,6 +2017,48 @@ fail: return r; } +static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) { + const uint8_t* p; + bool found_dau_dhu_n3u = false; + size_t l; + + /* Checks whether the specified OPT RR is well-formed and whether it contains RFC6975 data (which is not OK in + * a reply). */ + + assert(rr); + assert(rr->key->type == DNS_TYPE_OPT); + + /* Check that the version is 0 */ + if (((rr->ttl >> 16) & UINT32_C(0xFF)) != 0) + return false; + + p = rr->opt.data; + l = rr->opt.size; + while (l > 0) { + uint16_t option_code, option_length; + + /* At least four bytes for OPTION-CODE and OPTION-LENGTH are required */ + if (l < 4U) + return false; + + option_code = unaligned_read_be16(p); + option_length = unaligned_read_be16(p + 2); + + if (l < option_length + 4U) + return false; + + /* RFC 6975 DAU, DHU or N3U fields found. */ + if (IN_SET(option_code, 5, 6, 7)) + found_dau_dhu_n3u = true; + + p += option_length + 4U; + l -= option_length + 4U; + } + + *rfc6975 = found_dau_dhu_n3u; + return true; +} + int dns_packet_extract(DnsPacket *p) { _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; @@ -2064,6 +2106,9 @@ int dns_packet_extract(DnsPacket *p) { n = DNS_PACKET_RRCOUNT(p); if (n > 0) { + DnsResourceRecord *previous = NULL; + bool bad_opt = false; + answer = dns_answer_new(n); if (!answer) { r = -ENOMEM; @@ -2078,36 +2123,62 @@ int dns_packet_extract(DnsPacket *p) { if (r < 0) goto finish; + /* Try to reduce memory usage a bit */ + if (previous) + dns_resource_key_reduce(&rr->key, &previous->key); + if (rr->key->type == DNS_TYPE_OPT) { + bool has_rfc6975; + + if (p->opt || bad_opt) { + /* Multiple OPT RRs? if so, let's ignore all, because there's something wrong + * with the server, and if one is valid we wouldn't know which one. */ + log_debug("Multiple OPT RRs detected, ignoring all."); + bad_opt = true; + continue; + } if (!dns_name_is_root(DNS_RESOURCE_KEY_NAME(rr->key))) { - r = -EBADMSG; - goto finish; + /* If the OPT RR qis not owned by the root domain, then it is bad, let's ignore + * it. */ + log_debug("OPT RR is not owned by root domain, ignoring."); + bad_opt = true; + continue; + } + + if (i < DNS_PACKET_ANCOUNT(p) + DNS_PACKET_NSCOUNT(p)) { + /* OPT RR is in the wrong section? Some Belkin routers do this. This is a hint + * the EDNS implementation is borked, like the Belkin one is, hence ignore + * it. */ + log_debug("OPT RR in wrong section, ignoring."); + bad_opt = true; + continue; } - /* Note that we accept the OPT RR in - * any section, not just in the - * additional section, as some routers - * (Belkin!) blindly copy the OPT RR - * from the query to the reply packet, - * and don't get the section right. */ + if (!opt_is_good(rr, &has_rfc6975)) { + log_debug("Malformed OPT RR, ignoring."); + bad_opt = true; + continue; + } - /* Two OPT RRs? */ - if (p->opt) { - r = -EBADMSG; - goto finish; + if (has_rfc6975) { + /* OPT RR contains RFC6975 algorithm data, then this is indication that the + * server just copied the OPT it got from us (which contained that data) back + * into the reply. If so, then it doesn't properly support EDNS, as RFC6975 + * makes it very clear that the algorithm data should only be contained in + * questions, never in replies. Crappy Belkin copy the OPT data for example, + * hence let's detect this so that we downgrade early. */ + log_debug("OPT RR contained RFC6975 data, ignoring."); + bad_opt = true; + continue; } p->opt = dns_resource_record_ref(rr); } else { - /* According to RFC 4795, section - * 2.9. only the RRs from the Answer - * section shall be cached. Hence mark - * only those RRs as cacheable by - * default, but not the ones from the - * Additional or Authority - * sections. */ + /* According to RFC 4795, section 2.9. only the RRs from the Answer section shall be + * cached. Hence mark only those RRs as cacheable by default, but not the ones from the + * Additional or Authority sections. */ r = dns_answer_add(answer, rr, p->ifindex, (i < DNS_PACKET_ANCOUNT(p) ? DNS_ANSWER_CACHEABLE : 0) | @@ -2116,6 +2187,9 @@ int dns_packet_extract(DnsPacket *p) { goto finish; } } + + if (bad_opt) + p->opt = dns_resource_record_unref(p->opt); } p->question = question; diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c index 1948d59fc4..c6da8d0a87 100644 --- a/src/resolve/resolved-dns-query.c +++ b/src/resolve/resolved-dns-query.c @@ -1120,8 +1120,6 @@ static int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) assert(q); - log_debug("Following CNAME %s → %s", dns_question_first_name(q->question), cname->cname.name); - q->n_cname_redirects ++; if (q->n_cname_redirects > CNAME_MAX) return -ELOOP; @@ -1130,6 +1128,8 @@ static int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) if (r < 0) return r; + log_debug("Following CNAME/DNAME %s → %s", dns_question_first_name(q->question), dns_question_first_name(nq)); + dns_question_unref(q->question); q->question = nq; nq = NULL; diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c index dbf840157f..7273ef3825 100644 --- a/src/resolve/resolved-dns-rr.c +++ b/src/resolve/resolved-dns-rr.c @@ -334,6 +334,46 @@ int dns_resource_key_to_string(const DnsResourceKey *key, char **ret) { return 0; } +bool dns_resource_key_reduce(DnsResourceKey **a, DnsResourceKey **b) { + assert(a); + assert(b); + + /* Try to replace one RR key by another if they are identical, thus saving a bit of memory. Note that we do + * this only for RR keys, not for RRs themselves, as they carry a lot of additional metadata (where they come + * from, validity data, and suchlike), and cannot be replaced so easily by other RRs that have the same + * superficial data. */ + + if (!*a) + return false; + if (!*b) + return false; + + /* We refuse merging const keys */ + if ((*a)->n_ref == (unsigned) -1) + return false; + if ((*b)->n_ref == (unsigned) -1) + return false; + + /* Already the same? */ + if (*a == *b) + return true; + + /* Are they really identical? */ + if (dns_resource_key_equal(*a, *b) <= 0) + return false; + + /* Keep the one which already has more references. */ + if ((*a)->n_ref > (*b)->n_ref) { + dns_resource_key_unref(*b); + *b = dns_resource_key_ref(*a); + } else { + dns_resource_key_unref(*a); + *a = dns_resource_key_ref(*b); + } + + return true; +} + DnsResourceRecord* dns_resource_record_new(DnsResourceKey *key) { DnsResourceRecord *rr; @@ -344,6 +384,7 @@ DnsResourceRecord* dns_resource_record_new(DnsResourceKey *key) { rr->n_ref = 1; rr->key = dns_resource_key_ref(key); rr->expiry = USEC_INFINITY; + rr->n_skip_labels_signer = rr->n_skip_labels_source = (unsigned) -1; return rr; } @@ -1085,6 +1126,88 @@ int dns_resource_record_to_wire_format(DnsResourceRecord *rr, bool canonical) { return 0; } +int dns_resource_record_signer(DnsResourceRecord *rr, const char **ret) { + const char *n; + int r; + + assert(rr); + assert(ret); + + /* Returns the RRset's signer, if it is known. */ + + if (rr->n_skip_labels_signer == (unsigned) -1) + return -ENODATA; + + n = DNS_RESOURCE_KEY_NAME(rr->key); + r = dns_name_skip(n, rr->n_skip_labels_signer, &n); + if (r < 0) + return r; + if (r == 0) + return -EINVAL; + + *ret = n; + return 0; +} + +int dns_resource_record_source(DnsResourceRecord *rr, const char **ret) { + const char *n; + int r; + + assert(rr); + assert(ret); + + /* Returns the RRset's synthesizing source, if it is known. */ + + if (rr->n_skip_labels_source == (unsigned) -1) + return -ENODATA; + + n = DNS_RESOURCE_KEY_NAME(rr->key); + r = dns_name_skip(n, rr->n_skip_labels_source, &n); + if (r < 0) + return r; + if (r == 0) + return -EINVAL; + + *ret = n; + return 0; +} + +int dns_resource_record_is_signer(DnsResourceRecord *rr, const char *zone) { + const char *signer; + int r; + + assert(rr); + + r = dns_resource_record_signer(rr, &signer); + if (r < 0) + return r; + + return dns_name_equal(zone, signer); +} + +int dns_resource_record_is_synthetic(DnsResourceRecord *rr) { + int r; + + assert(rr); + + /* Returns > 0 if the RR is generated from a wildcard, and is not the asterisk name itself */ + + if (rr->n_skip_labels_source == (unsigned) -1) + return -ENODATA; + + if (rr->n_skip_labels_source == 0) + return 0; + + if (rr->n_skip_labels_source > 1) + return 1; + + r = dns_name_startswith(DNS_RESOURCE_KEY_NAME(rr->key), "*"); + if (r < 0) + return r; + + return !r; +} + static void dns_resource_record_hash_func(const void *i, struct siphash *state) { const DnsResourceRecord *rr = i; diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h index fe29a41566..d9c31e81c5 100644 --- a/src/resolve/resolved-dns-rr.h +++ b/src/resolve/resolved-dns-rr.h @@ -81,7 +81,7 @@ enum { }; struct DnsResourceKey { - unsigned n_ref; + unsigned n_ref; /* (unsigned -1) for const keys, see below */ uint16_t class, type; char *_name; /* don't access directy, use DNS_RESOURCE_KEY_NAME()! */ }; @@ -108,14 +108,24 @@ struct DnsTxtItem { struct DnsResourceRecord { unsigned n_ref; DnsResourceKey *key; + char *to_string; + uint32_t ttl; usec_t expiry; /* RRSIG signature expiry */ + + /* How many labels to strip to determine "signer" of the RRSIG (aka, the zone). -1 if not signed. */ + unsigned n_skip_labels_signer; + /* How many labels to strip to determine "synthesizing source" of this RR, i.e. the wildcard's immediate parent. -1 if not signed. */ + unsigned n_skip_labels_source; + bool unparseable:1; + bool wire_format_canonical:1; void *wire_format; size_t wire_format_size; size_t wire_format_rdata_offset; + union { struct { void *data; @@ -284,6 +294,8 @@ static inline bool dns_key_is_shared(const DnsResourceKey *key) { return IN_SET(key->type, DNS_TYPE_PTR); } +bool dns_resource_key_reduce(DnsResourceKey **a, DnsResourceKey **b); + DnsResourceRecord* dns_resource_record_new(DnsResourceKey *key); DnsResourceRecord* dns_resource_record_new_full(uint16_t class, uint16_t type, const char *name); DnsResourceRecord* dns_resource_record_ref(DnsResourceRecord *rr); @@ -296,6 +308,11 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(DnsResourceRecord*, dns_resource_record_unref); int dns_resource_record_to_wire_format(DnsResourceRecord *rr, bool canonical); +int dns_resource_record_signer(DnsResourceRecord *rr, const char **ret); +int dns_resource_record_source(DnsResourceRecord *rr, const char **ret); +int dns_resource_record_is_signer(DnsResourceRecord *rr, const char *zone); +int dns_resource_record_is_synthetic(DnsResourceRecord *rr); + DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i); bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b); diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c index 0969e31e8a..949c0d66e1 100644 --- a/src/resolve/resolved-dns-server.c +++ b/src/resolve/resolved-dns-server.c @@ -232,7 +232,9 @@ static void dns_server_verified(DnsServer *s, DnsServerFeatureLevel level) { return; if (s->verified_feature_level != level) { - log_debug("Verified feature level %s.", dns_server_feature_level_to_string(level)); + log_debug("Verified we get a response at feature level %s from DNS server %s.", + dns_server_feature_level_to_string(level), + dns_server_string(s)); s->verified_feature_level = level; } @@ -246,13 +248,18 @@ void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLeve if (s->possible_feature_level == level) s->n_failed_udp = 0; + /* If the RRSIG data is missing, then we can only validate EDNS0 at max */ + if (s->packet_rrsig_missing && level >= DNS_SERVER_FEATURE_LEVEL_DO) + level = DNS_SERVER_FEATURE_LEVEL_DO - 1; + + /* If the OPT RR got lost, then we can only validate UDP at max */ + if (s->packet_bad_opt && level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) + level = DNS_SERVER_FEATURE_LEVEL_EDNS0 - 1; + + /* Even if we successfully receive a reply to a request announcing support for large packets, + that does not mean we can necessarily receive large packets. */ if (level == DNS_SERVER_FEATURE_LEVEL_LARGE) - /* Even if we successfully receive a reply to a request announcing support for large packets, - that does not mean we can necessarily receive large packets. */ - dns_server_verified(s, DNS_SERVER_FEATURE_LEVEL_LARGE - 1); - else - /* A successful UDP reply, verifies UDP, ENDS0 and DO levels */ - dns_server_verified(s, level); + level = DNS_SERVER_FEATURE_LEVEL_LARGE - 1; } else if (protocol == IPPROTO_TCP) { @@ -260,9 +267,11 @@ void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLeve s->n_failed_tcp = 0; /* Successful TCP connections are only useful to verify the TCP feature level. */ - dns_server_verified(s, DNS_SERVER_FEATURE_LEVEL_TCP); + level = DNS_SERVER_FEATURE_LEVEL_TCP; } + dns_server_verified(s, level); + /* Remember the size of the largest UDP packet we received from a server, we know that we can always announce support for packets with at least this size. */ @@ -294,7 +303,6 @@ void dns_server_packet_lost(DnsServer *s, int protocol, DnsServerFeatureLevel le void dns_server_packet_failed(DnsServer *s, DnsServerFeatureLevel level) { assert(s); - assert(s->manager); /* Invoked whenever we get a FORMERR, SERVFAIL or NOTIMP rcode from a server. */ @@ -306,7 +314,6 @@ void dns_server_packet_failed(DnsServer *s, DnsServerFeatureLevel level) { void dns_server_packet_truncated(DnsServer *s, DnsServerFeatureLevel level) { assert(s); - assert(s->manager); /* Invoked whenever we get a packet with TC bit set. */ @@ -316,13 +323,30 @@ void dns_server_packet_truncated(DnsServer *s, DnsServerFeatureLevel level) { s->packet_truncated = true; } -void dns_server_packet_rrsig_missing(DnsServer *s) { +void dns_server_packet_rrsig_missing(DnsServer *s, DnsServerFeatureLevel level) { assert(s); - assert(s->manager); - log_warning("DNS server %s does not augment replies with RRSIG records, DNSSEC not available.", dns_server_string(s)); + if (level < DNS_SERVER_FEATURE_LEVEL_DO) + return; + + /* If the RRSIG RRs are missing, we have to downgrade what we previously verified */ + if (s->verified_feature_level >= DNS_SERVER_FEATURE_LEVEL_DO) + s->verified_feature_level = DNS_SERVER_FEATURE_LEVEL_DO-1; + + s->packet_rrsig_missing = true; +} + +void dns_server_packet_bad_opt(DnsServer *s, DnsServerFeatureLevel level) { + assert(s); - s->rrsig_missing = true; + if (level < DNS_SERVER_FEATURE_LEVEL_EDNS0) + return; + + /* If the OPT RR got lost, we have to downgrade what we previously verified */ + if (s->verified_feature_level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) + s->verified_feature_level = DNS_SERVER_FEATURE_LEVEL_EDNS0-1; + + s->packet_bad_opt = true; } static bool dns_server_grace_period_expired(DnsServer *s) { @@ -351,6 +375,8 @@ static void dns_server_reset_counters(DnsServer *s) { s->n_failed_tcp = 0; s->packet_failed = false; s->packet_truncated = false; + s->packet_bad_opt = false; + s->packet_rrsig_missing = false; s->verified_usec = 0; } @@ -361,11 +387,9 @@ DnsServerFeatureLevel dns_server_possible_feature_level(DnsServer *s) { dns_server_grace_period_expired(s)) { s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_BEST; - s->rrsig_missing = false; - dns_server_reset_counters(s); - log_info("Grace period over, resuming full feature set (%s) for DNS server %s", + log_info("Grace period over, resuming full feature set (%s) for DNS server %s.", dns_server_feature_level_to_string(s->possible_feature_level), dns_server_string(s)); @@ -375,46 +399,75 @@ DnsServerFeatureLevel dns_server_possible_feature_level(DnsServer *s) { DnsServerFeatureLevel p = s->possible_feature_level; if (s->n_failed_tcp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && - s->possible_feature_level == DNS_SERVER_FEATURE_LEVEL_TCP) + s->possible_feature_level == DNS_SERVER_FEATURE_LEVEL_TCP) { /* We are at the TCP (lowest) level, and we tried a couple of TCP connections, and it didn't * work. Upgrade back to UDP again. */ + log_debug("Reached maximum number of failed TCP connection attempts, trying UDP again..."); + s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_UDP; + + } else if (s->packet_bad_opt && + s->possible_feature_level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) { + + /* A reply to one of our EDNS0 queries didn't carry a valid OPT RR, then downgrade to below + * EDNS0 levels. After all, some records generate different responses with and without OPT RR + * in the request. Example: + * https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ + + log_debug("Server doesn't support EDNS(0) properly, downgrading feature level..."); s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_UDP; - else if ((s->n_failed_udp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && - s->possible_feature_level >= DNS_SERVER_FEATURE_LEVEL_UDP) || - (s->packet_failed && - s->possible_feature_level > DNS_SERVER_FEATURE_LEVEL_UDP) || - (s->n_failed_tcp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && - s->packet_truncated && - s->possible_feature_level > DNS_SERVER_FEATURE_LEVEL_UDP)) - - /* Downgrade the feature one level, maybe things will work better then. We do this under any of - * three conditions: - * - * 1. We lost too many UDP packets in a row, and are on a feature level of UDP or higher. If - * the packets are lost, maybe the server cannot parse them, hence downgrading sounds like a - * good idea. We might downgrade all the way down to TCP this way. - * - * 2. We got a failure packet, and are at a feature level above UDP. Note that in this case we - * downgrade no further than UDP, under the assumption that a failure packet indicates an - * incompatible packet contents, but not a problem with the transport. - * - * 3. We got too many TCP connection failures in a row, we had at least one truncated packet, - * and are on a feature level above UDP. By downgrading things and getting rid of DNSSEC or - * EDNS0 data we hope to make the packet smaller, so that it still works via UDP given that - * TCP appears not to be a fallback. Note that if we are already at the lowest UDP level, we - * don't go further down, since that's TCP, and TCP failed too often after all. - */ + } else if (s->packet_rrsig_missing && + s->possible_feature_level >= DNS_SERVER_FEATURE_LEVEL_DO) { + + /* RRSIG data was missing on a EDNS0 packet with DO bit set. This means the server doesn't + * augment responses with DNSSEC RRs. If so, let's better not ask the server for it anymore, + * after all some servers generate different replies depending if an OPT RR is in the query or + * not. */ + + log_debug("Detected server responses lack RRSIG records, downgrading feature level..."); + s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_EDNS0; + + } else if (s->n_failed_udp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && + s->possible_feature_level >= DNS_SERVER_FEATURE_LEVEL_UDP) { + + /* We lost too many UDP packets in a row, and are on a feature level of UDP or higher. If the + * packets are lost, maybe the server cannot parse them, hence downgrading sounds like a good + * idea. We might downgrade all the way down to TCP this way. */ + + log_debug("Lost too many UDP packets, downgrading feature level..."); + s->possible_feature_level--; + + } else if (s->packet_failed && + s->possible_feature_level > DNS_SERVER_FEATURE_LEVEL_UDP) { + + /* We got a failure packet, and are at a feature level above UDP. Note that in this case we + * downgrade no further than UDP, under the assumption that a failure packet indicates an + * incompatible packet contents, but not a problem with the transport. */ + log_debug("Got server failure, downgrading feature level..."); s->possible_feature_level--; + } else if (s->n_failed_tcp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && + s->packet_truncated && + s->possible_feature_level > DNS_SERVER_FEATURE_LEVEL_UDP) { + + /* We got too many TCP connection failures in a row, we had at least one truncated packet, and + * are on a feature level above UDP. By downgrading things and getting rid of DNSSEC or EDNS0 + * data we hope to make the packet smaller, so that it still works via UDP given that TCP + * appears not to be a fallback. Note that if we are already at the lowest UDP level, we don't + * go further down, since that's TCP, and TCP failed too often after all. */ + + log_debug("Got too many failed TCP connection failures and truncated UDP packets, downgrading feature level..."); + s->possible_feature_level--; + } + if (p != s->possible_feature_level) { /* We changed the feature level, reset the counting */ dns_server_reset_counters(s); - log_warning("Using degraded feature set (%s) for DNS server %s", + log_warning("Using degraded feature set (%s) for DNS server %s.", dns_server_feature_level_to_string(s->possible_feature_level), dns_server_string(s)); } @@ -468,7 +521,10 @@ bool dns_server_dnssec_supported(DnsServer *server) { if (server->possible_feature_level < DNS_SERVER_FEATURE_LEVEL_DO) return false; - if (server->rrsig_missing) + if (server->packet_bad_opt) + return false; + + if (server->packet_rrsig_missing) return false; /* DNSSEC servers need to support TCP properly (see RFC5966), if they don't, we assume DNSSEC is borked too */ diff --git a/src/resolve/resolved-dns-server.h b/src/resolve/resolved-dns-server.h index 323f702903..02bd3463a7 100644 --- a/src/resolve/resolved-dns-server.h +++ b/src/resolve/resolved-dns-server.h @@ -68,20 +68,20 @@ struct DnsServer { DnsServerFeatureLevel verified_feature_level; DnsServerFeatureLevel possible_feature_level; + size_t received_udp_packet_max; + unsigned n_failed_udp; unsigned n_failed_tcp; + bool packet_failed:1; bool packet_truncated:1; + bool packet_bad_opt:1; + bool packet_rrsig_missing:1; + usec_t verified_usec; usec_t features_grace_period_usec; - /* Indicates whether responses are augmented with RRSIG by - * server or not. Note that this is orthogonal to the feature - * level stuff, as it's only information describing responses, - * and has no effect on how the questions are asked. */ - bool rrsig_missing:1; - /* Used when GC'ing old DNS servers when configuration changes. */ bool marked:1; @@ -108,7 +108,8 @@ void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLeve void dns_server_packet_lost(DnsServer *s, int protocol, DnsServerFeatureLevel level, usec_t usec); void dns_server_packet_failed(DnsServer *s, DnsServerFeatureLevel level); void dns_server_packet_truncated(DnsServer *s, DnsServerFeatureLevel level); -void dns_server_packet_rrsig_missing(DnsServer *s); +void dns_server_packet_rrsig_missing(DnsServer *s, DnsServerFeatureLevel level); +void dns_server_packet_bad_opt(DnsServer *s, DnsServerFeatureLevel level); DnsServerFeatureLevel dns_server_possible_feature_level(DnsServer *s); diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index c7d2d82ecf..393171a2ad 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -43,6 +43,17 @@ static void dns_transaction_reset_answer(DnsTransaction *t) { t->answer_nsec_ttl = (uint32_t) -1; } +static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) { + DnsTransaction *z; + + assert(t); + + while ((z = set_steal_first(t->dnssec_transactions))) { + set_remove(z->notify_transactions, t); + dns_transaction_gc(z); + } +} + static void dns_transaction_close_connection(DnsTransaction *t) { assert(t); @@ -95,10 +106,7 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) { set_remove(z->dnssec_transactions, t); set_free(t->notify_transactions); - while ((z = set_steal_first(t->dnssec_transactions))) { - set_remove(z->notify_transactions, t); - dns_transaction_gc(z); - } + dns_transaction_flush_dnssec_transactions(t); set_free(t->dnssec_transactions); dns_answer_unref(t->validated_keys); @@ -354,6 +362,25 @@ static void dns_transaction_retry(DnsTransaction *t) { dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); } +static int dns_transaction_maybe_restart(DnsTransaction *t) { + assert(t); + + if (!t->server) + return 0; + + if (t->current_feature_level <= dns_server_possible_feature_level(t->server)) + return 0; + + /* The server's current feature level is lower than when we sent the original query. We learnt something from + the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to + restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include + OPT RR or DO bit. One of these cases is documented here, for example: + https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ + + log_debug("Server feature level is now lower than when we began our transaction. Restarting."); + return dns_transaction_go(t); +} + static int on_stream_complete(DnsStream *s, int error) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; DnsTransaction *t; @@ -538,6 +565,16 @@ static void dns_transaction_process_dnssec(DnsTransaction *t) { if (dns_transaction_dnssec_is_live(t)) return; + /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better + * restart the lookup immediately. */ + r = dns_transaction_maybe_restart(t); + if (r < 0) { + dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); + return; + } + if (r > 0) /* Transaction got restarted... */ + return; + /* All our auxiliary DNSSEC transactions are complete now. Try * to validate our RRset now. */ r = dns_transaction_validate_dnssec(t); @@ -675,8 +712,6 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { return; } else if (DNS_PACKET_TC(p)) dns_server_packet_truncated(t->server, t->current_feature_level); - else - dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, ts - t->start_usec, p->size); break; @@ -726,13 +761,30 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { return; } - /* Parse message, if it isn't parsed yet. */ + /* After the superficial checks, actually parse the message. */ r = dns_packet_extract(p); if (r < 0) { dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); return; } + /* Report that the OPT RR was missing */ + if (t->server) { + if (!p->opt) + dns_server_packet_bad_opt(t->server, t->current_feature_level); + + dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, ts - t->start_usec, p->size); + } + + /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */ + r = dns_transaction_maybe_restart(t); + if (r < 0) { + dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); + return; + } + if (r > 0) /* Transaction got restarted... */ + return; + if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) { /* Only consider responses with equivalent query section to the request */ @@ -961,6 +1013,7 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { t->start_usec = ts; dns_transaction_reset_answer(t); + dns_transaction_flush_dnssec_transactions(t); /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ if (t->scope->protocol == DNS_PROTOCOL_DNS) { @@ -1774,6 +1827,12 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) { if (r > 0) continue; + r = dns_answer_has_dname_for_cname(t->answer, rr); + if (r < 0) + return r; + if (r > 0) + continue; + name = DNS_RESOURCE_KEY_NAME(rr->key); r = dns_name_parent(&name); if (r < 0) @@ -1950,7 +2009,7 @@ static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { - r = dnssec_verify_dnskey_search(rr, t->validated_keys); + r = dnssec_verify_dnskey_by_ds_search(rr, t->validated_keys); if (r < 0) return r; if (r == 0) @@ -2416,7 +2475,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { if (!dns_transaction_dnssec_supported_full(t)) { /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; - log_debug("Cannot validate response, server lacks DNSSEC support."); + log_debug("Not validating response, server lacks DNSSEC support."); return 0; } @@ -2537,11 +2596,9 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { * that no matching non-wildcard RR exists.*/ /* First step, determine the source of synthesis */ - r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rrsig->rrsig.labels, &source); + r = dns_resource_record_source(rrsig, &source); if (r < 0) return r; - if (r == 0) - return -EBADMSG; r = dnssec_test_positive_wildcard( validated, @@ -2592,7 +2649,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { /* This is an RR we know has to be signed. If it isn't this means * the server is not attaching RRSIGs, hence complain. */ - dns_server_packet_rrsig_missing(t->server); + dns_server_packet_rrsig_missing(t->server, t->current_feature_level); if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { @@ -2668,17 +2725,30 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { if (r < 0) return r; if (r > 0) { - /* This is a primary response - * to our question, and it - * failed validation. That's - * fatal. */ - t->answer_dnssec_result = result; - return 0; + + /* Look for a matching DNAME for this CNAME */ + r = dns_answer_has_dname_for_cname(t->answer, rr); + if (r < 0) + return r; + if (r == 0) { + /* Also look among the stuff we already validated */ + r = dns_answer_has_dname_for_cname(validated, rr); + if (r < 0) + return r; + } + + if (r == 0) { + /* This is a primary response to our question, and it failed validation. That's + * fatal. */ + t->answer_dnssec_result = result; + return 0; + } + + /* This is a primary response, but we do have a DNAME RR in the RR that can replay this + * CNAME, hence rely on that, and we can remove the CNAME in favour of it. */ } - /* This is just some auxiliary - * data. Just remove the RRset and - * continue. */ + /* This is just some auxiliary data. Just remove the RRset and continue. */ r = dns_answer_remove_by_key(&t->answer, rr->key); if (r < 0) return r; diff --git a/src/resolve/resolved-dns-trust-anchor.c b/src/resolve/resolved-dns-trust-anchor.c index 9bee44b5c7..02d7ac91e1 100644 --- a/src/resolve/resolved-dns-trust-anchor.c +++ b/src/resolve/resolved-dns-trust-anchor.c @@ -665,7 +665,7 @@ static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceReco * DS fingerprint will be the one of the * unrevoked DNSKEY, but the one we got passed * here has the bit set. */ - r = dnssec_verify_dnskey(revoked_dnskey, anchor, true); + r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true); if (r < 0) return r; if (r == 0) diff --git a/src/resolve/resolved-link.c b/src/resolve/resolved-link.c index 928307e004..1e8f88024b 100644 --- a/src/resolve/resolved-link.c +++ b/src/resolve/resolved-link.c @@ -279,6 +279,7 @@ clear: static int link_update_dnssec_mode(Link *l) { _cleanup_free_ char *m = NULL; + DnssecMode mode; int r; assert(l); @@ -291,12 +292,23 @@ static int link_update_dnssec_mode(Link *l) { if (r < 0) goto clear; - l->dnssec_mode = dnssec_mode_from_string(m); - if (l->dnssec_mode < 0) { + mode = dnssec_mode_from_string(m); + if (mode < 0) { r = -EINVAL; goto clear; } + if ((l->dnssec_mode == DNSSEC_NO && mode != DNSSEC_NO) || + (l->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE && mode == DNSSEC_YES)) { + + /* When switching from non-DNSSEC mode to DNSSEC mode, flush the cache. Also when switching from the + * allow-downgrade mode to full DNSSEC mode, flush it too. */ + if (l->unicast_scope) + dns_cache_flush(&l->unicast_scope->cache); + } + + l->dnssec_mode = mode; + return 0; clear: diff --git a/src/resolve/test-dnssec-complex.c b/src/resolve/test-dnssec-complex.c new file mode 100644 index 0000000000..3093fb052d --- /dev/null +++ b/src/resolve/test-dnssec-complex.c @@ -0,0 +1,146 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "sd-bus.h" + +#include "alloc-util.h" +#include "bus-common-errors.h" +#include "dns-type.h" +#include "random-util.h" +#include "string-util.h" +#include "time-util.h" + +#define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC) + +static void test_lookup(sd_bus *bus, const char *name, uint16_t type, const char *result) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *req = NULL, *reply = NULL; + _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; + _cleanup_free_ char *m = NULL; + int r; + + /* If the name starts with a dot, we prefix one to three random labels */ + if (startswith(name, ".")) { + uint64_t i, u; + + u = 1 + (random_u64() & 3); + name ++; + + for (i = 0; i < u; i++) { + _cleanup_free_ char *b = NULL; + char *x; + + assert_se(asprintf(&b, "x%" PRIu64 "x", random_u64())); + x = strjoin(b, ".", name, NULL); + assert_se(x); + free(m); + name = m = x; + } + } + + assert_se(sd_bus_message_new_method_call( + bus, + &req, + "org.freedesktop.resolve1", + "/org/freedesktop/resolve1", + "org.freedesktop.resolve1.Manager", + "ResolveRecord") >= 0); + + assert_se(sd_bus_message_append(req, "isqqt", 0, name, DNS_CLASS_IN, type, UINT64_C(0)) >= 0); + + r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply); + + if (r < 0) { + assert_se(result); + assert_se(sd_bus_error_has_name(&error, result)); + log_info("[OK] %s/%s resulted in <%s>.", name, dns_type_to_string(type), error.name); + } else { + assert_se(!result); + log_info("[OK] %s/%s succeeded.", name, dns_type_to_string(type)); + } +} + +int main(int argc, char* argv[]) { + _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL; + + /* Note that this is a manual test as it requires: + * + * Full network access + * A DNSSEC capable DNS server + * That zones contacted are still set up as they were when I wrote this. + */ + + assert_se(sd_bus_open_system(&bus) >= 0); + + /* Normally signed */ + test_lookup(bus, "www.eurid.eu", DNS_TYPE_A, NULL); + test_lookup(bus, "sigok.verteiltesysteme.net", DNS_TYPE_A, NULL); + + /* Normally signed, NODATA */ + test_lookup(bus, "www.eurid.eu", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR); + test_lookup(bus, "sigok.verteiltesysteme.net", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR); + + /* Invalid signature */ + test_lookup(bus, "sigfail.verteiltesysteme.net", DNS_TYPE_A, BUS_ERROR_DNSSEC_FAILED); + + /* Invalid signature, RSA, wildcard */ + test_lookup(bus, ".wilda.rhybar.0skar.cz", DNS_TYPE_A, BUS_ERROR_DNSSEC_FAILED); + + /* Invalid signature, ECDSA, wildcard */ + test_lookup(bus, ".wilda.rhybar.ecdsa.0skar.cz", DNS_TYPE_A, BUS_ERROR_DNSSEC_FAILED); + + /* NXDOMAIN in NSEC domain */ + test_lookup(bus, "hhh.nasa.gov", DNS_TYPE_A, _BUS_ERROR_DNS "NXDOMAIN"); + + /* wildcard, NSEC zone */ + test_lookup(bus, ".wilda.nsec.0skar.cz", DNS_TYPE_A, NULL); + + /* wildcard, NSEC zone, NODATA */ + test_lookup(bus, ".wilda.nsec.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR); + + /* wildcard, NSEC3 zone */ + test_lookup(bus, ".wilda.0skar.cz", DNS_TYPE_A, NULL); + + /* wildcard, NSEC3 zone, NODATA */ + test_lookup(bus, ".wilda.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR); + + /* wildcard, NSEC zone, CNAME */ + test_lookup(bus, ".wild.nsec.0skar.cz", DNS_TYPE_A, NULL); + + /* wildcard, NSEC zone, NODATA, CNAME */ + test_lookup(bus, ".wild.nsec.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR); + + /* wildcard, NSEC3 zone, CNAME */ + test_lookup(bus, ".wild.0skar.cz", DNS_TYPE_A, NULL); + + /* wildcard, NSEC3 zone, NODATA, CNAME */ + test_lookup(bus, ".wild.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR); + + /* NODATA due to empty non-terminal in NSEC domain */ + test_lookup(bus, "herndon.nasa.gov", DNS_TYPE_A, BUS_ERROR_NO_SUCH_RR); + + /* NXDOMAIN in NSEC root zone: */ + test_lookup(bus, "jasdhjas.kjkfgjhfjg", DNS_TYPE_A, _BUS_ERROR_DNS "NXDOMAIN"); + + /* NXDOMAIN in NSEC3 .com zone: */ + test_lookup(bus, "kjkfgjhfjgsdfdsfd.com", DNS_TYPE_A, _BUS_ERROR_DNS "NXDOMAIN"); + + return 0; +} diff --git a/src/resolve/test-dnssec.c b/src/resolve/test-dnssec.c index 0c9efde1fe..45fe1997e2 100644 --- a/src/resolve/test-dnssec.c +++ b/src/resolve/test-dnssec.c @@ -270,8 +270,8 @@ static void test_dnssec_verify_dns_key(void) { log_info("DNSKEY: %s", strna(dns_resource_record_to_string(dnskey))); log_info("DNSKEY keytag: %u", dnssec_keytag(dnskey, false)); - assert_se(dnssec_verify_dnskey(dnskey, ds1, false) > 0); - assert_se(dnssec_verify_dnskey(dnskey, ds2, false) > 0); + assert_se(dnssec_verify_dnskey_by_ds(dnskey, ds1, false) > 0); + assert_se(dnssec_verify_dnskey_by_ds(dnskey, ds2, false) > 0); } static void test_dnssec_canonicalize_one(const char *original, const char *canonical, int r) { diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c index d1fb97fe92..04624734dc 100644 --- a/src/shared/dns-domain.c +++ b/src/shared/dns-domain.c @@ -1157,22 +1157,20 @@ finish: return 0; } -int dns_name_suffix(const char *name, unsigned n_labels, const char **ret) { - const char* labels[DNS_N_LABELS_MAX+1]; - unsigned n = 0; +static int dns_name_build_suffix_table(const char *name, const char*table[]) { const char *p; + unsigned n = 0; int r; assert(name); - assert(ret); + assert(table); p = name; for (;;) { if (n > DNS_N_LABELS_MAX) return -EINVAL; - labels[n] = p; - + table[n] = p; r = dns_name_parent(&p); if (r < 0) return r; @@ -1182,13 +1180,47 @@ int dns_name_suffix(const char *name, unsigned n_labels, const char **ret) { n++; } - if (n < n_labels) + return (int) n; +} + +int dns_name_suffix(const char *name, unsigned n_labels, const char **ret) { + const char* labels[DNS_N_LABELS_MAX+1]; + int n; + + assert(name); + assert(ret); + + n = dns_name_build_suffix_table(name, labels); + if (n < 0) + return n; + + if ((unsigned) n < n_labels) return -EINVAL; *ret = labels[n - n_labels]; return (int) (n - n_labels); } +int dns_name_skip(const char *a, unsigned n_labels, const char **ret) { + int r; + + assert(a); + assert(ret); + + for (; n_labels > 0; n_labels --) { + r = dns_name_parent(&a); + if (r < 0) + return r; + if (r == 0) { + *ret = ""; + return 0; + } + } + + *ret = a; + return 1; +} + int dns_name_count_labels(const char *name) { unsigned n = 0; const char *p; @@ -1219,14 +1251,55 @@ int dns_name_equal_skip(const char *a, unsigned n_labels, const char *b) { assert(a); assert(b); - while (n_labels > 0) { + r = dns_name_skip(a, n_labels, &a); + if (r <= 0) + return r; - r = dns_name_parent(&a); - if (r <= 0) + return dns_name_equal(a, b); +} + +int dns_name_common_suffix(const char *a, const char *b, const char **ret) { + const char *a_labels[DNS_N_LABELS_MAX+1], *b_labels[DNS_N_LABELS_MAX+1]; + int n = 0, m = 0, k = 0, r, q; + + assert(a); + assert(b); + assert(ret); + + /* Determines the common suffix of domain names a and b */ + + n = dns_name_build_suffix_table(a, a_labels); + if (n < 0) + return n; + + m = dns_name_build_suffix_table(b, b_labels); + if (m < 0) + return m; + + for (;;) { + char la[DNS_LABEL_MAX], lb[DNS_LABEL_MAX]; + const char *x, *y; + + if (k >= n || k >= m) { + *ret = a_labels[n - k]; + return 0; + } + + x = a_labels[n - 1 - k]; + r = dns_label_unescape_undo_idna(&x, la, sizeof(la)); + if (r < 0) return r; - n_labels --; - } + y = b_labels[m - 1 - k]; + q = dns_label_unescape_undo_idna(&y, lb, sizeof(lb)); + if (q < 0) + return q; - return dns_name_equal(a, b); + if (r != q || ascii_strcasecmp_n(la, lb, r) != 0) { + *ret = a_labels[n - k]; + return 0; + } + + k++; + } } diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h index 4fbe0a618f..5f9542ef98 100644 --- a/src/shared/dns-domain.h +++ b/src/shared/dns-domain.h @@ -104,4 +104,7 @@ int dns_service_split(const char *joined, char **name, char **type, char **domai int dns_name_suffix(const char *name, unsigned n_labels, const char **ret); int dns_name_count_labels(const char *name); +int dns_name_skip(const char *a, unsigned n_labels, const char **ret); int dns_name_equal_skip(const char *a, unsigned n_labels, const char *b); + +int dns_name_common_suffix(const char *a, const char *b, const char **ret); diff --git a/src/test/test-dns-domain.c b/src/test/test-dns-domain.c index fe3ae45349..987f1fc887 100644 --- a/src/test/test-dns-domain.c +++ b/src/test/test-dns-domain.c @@ -578,6 +578,26 @@ static void test_dns_name_compare_func(void) { assert_se(dns_name_compare_func("de.", "heise.de") != 0); } +static void test_dns_name_common_suffix_one(const char *a, const char *b, const char *result) { + const char *c; + + assert_se(dns_name_common_suffix(a, b, &c) >= 0); + assert_se(streq(c, result)); +} + +static void test_dns_name_common_suffix(void) { + test_dns_name_common_suffix_one("", "", ""); + test_dns_name_common_suffix_one("foo", "", ""); + test_dns_name_common_suffix_one("", "foo", ""); + test_dns_name_common_suffix_one("foo", "bar", ""); + test_dns_name_common_suffix_one("bar", "foo", ""); + test_dns_name_common_suffix_one("foo", "foo", "foo"); + test_dns_name_common_suffix_one("quux.foo", "foo", "foo"); + test_dns_name_common_suffix_one("foo", "quux.foo", "foo"); + test_dns_name_common_suffix_one("this.is.a.short.sentence", "this.is.another.short.sentence", "short.sentence"); + test_dns_name_common_suffix_one("FOO.BAR", "tEST.bAR", "BAR"); +} + int main(int argc, char *argv[]) { test_dns_label_unescape(); @@ -603,6 +623,7 @@ int main(int argc, char *argv[]) { test_dns_name_count_labels(); test_dns_name_equal_skip(); test_dns_name_compare_func(); + test_dns_name_common_suffix(); return 0; } |