diff --git a/doc/Changelog b/doc/Changelog index 23a65d2ae..12dfb3559 100644 --- a/doc/Changelog +++ b/doc/Changelog @@ -34,6 +34,11 @@ the report. - Fix that signatures are not allowed with revoked dnskeys. Thanks to Qifan Zhang, Palo Alto Networks for the report. + - Fix that a DNAME with an unsigned CNAME is checked for + the correct match. This stops that for certain zone + configurations an unchecked unsigned CNAME could get + secure status. Thanks to Qifan Zhang, Palo Alto Networks + for the report. 20 April 2026: Wouter - Fix compile warnings for thread setname routine, and test compile. diff --git a/testdata/dname_unsigned_cname.rpl b/testdata/dname_unsigned_cname.rpl new file mode 100644 index 000000000..60866378f --- /dev/null +++ b/testdata/dname_unsigned_cname.rpl @@ -0,0 +1,297 @@ +; config options +; The island of trust is at test. +server: + trust-anchor: "test. DS 1444 8 2 8a87d067fd09a5965244fe2e317dd26d182c468e0a7f26ecc4c7b479bf89db9b" + val-override-date: "20201020135527" + target-fetch-policy: "0 0 0 0 0" + qname-minimisation: "no" + fake-sha1: yes + trust-anchor-signaling: no + minimal-responses: no + iter-scrub-promiscuous: no + aggressive-nsec: yes + local-zone: test. nodefault + log-servfail: yes + +stub-zone: + name: "." + stub-addr: 193.0.14.129 # K.ROOT-SERVERS.NET. +CONFIG_END + +SCENARIO_BEGIN Test DNAME with an unsigned CNAME that mismatches the DNAME. +; The CNAME occurs later in a list of redirections. + +; K.ROOT-SERVERS.NET. +RANGE_BEGIN 0 100 + ADDRESS 193.0.14.129 +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR NOERROR +SECTION QUESTION +. IN NS +SECTION ANSWER +. IN NS K.ROOT-SERVERS.NET. +SECTION ADDITIONAL +K.ROOT-SERVERS.NET. IN A 193.0.14.129 +ENTRY_END + +ENTRY_BEGIN +MATCH opcode subdomain +ADJUST copy_id copy_query +REPLY QR NOERROR +SECTION QUESTION +test. IN NS +SECTION AUTHORITY +test. IN NS ns.test. +SECTION ADDITIONAL +ns.test. IN A 1.2.3.5 +ENTRY_END +RANGE_END + +; ns.test +RANGE_BEGIN 0 100 + ADDRESS 1.2.3.5 +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +test. IN NS +SECTION ANSWER +test. IN NS ns.test +test. 3600 IN RRSIG NS 8 1 3600 20201116135527 20201019135527 1444 test. RGCxIO32TbbLTk6xZmTr+fjYPH50hntBxeOQ2DIj2pDsmjALcHYtVkOfpfk2EhOhHZd+9PLuoJPbJh6a9NqLSFeBvr0XZoCZoQ2g0tCHUNHcH5EVjA2TuYBQem6DVYnPLJ3914aRx0uA1j42b8dC2xsam/XkOo7U+dLbUW2Os1s= +SECTION ADDITIONAL +ns.test. IN A 1.2.3.5 +ns.test. 3600 IN RRSIG A 8 2 3600 20201116135527 20201019135527 1444 test. GskCc4/k6GjH9V9Jz2V5L2XLiizbOeWkB0feSbf+aN859S3vxVvtuqkvIgwY4LafUO1QAn/pUcv9zA7rcFO++rlg+8t6gvZTo9p3v0bfeIv2uJDsfSBD5jDh0WXlxjekfnrKrQp7zE+GiA93tWwKUWKPvxXDgP+n886e6WcbHJw= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +ns.test. IN A +SECTION ANSWER +ns.test. IN A 1.2.3.5 +ns.test. 3600 IN RRSIG A 8 2 3600 20201116135527 20201019135527 1444 test. GskCc4/k6GjH9V9Jz2V5L2XLiizbOeWkB0feSbf+aN859S3vxVvtuqkvIgwY4LafUO1QAn/pUcv9zA7rcFO++rlg+8t6gvZTo9p3v0bfeIv2uJDsfSBD5jDh0WXlxjekfnrKrQp7zE+GiA93tWwKUWKPvxXDgP+n886e6WcbHJw= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +ns.test. IN AAAA +SECTION AUTHORITY +test. 3600 IN SOA ns.test. host.test. 20201 3600 1800 604800 3600 +test. 3600 IN RRSIG SOA 8 1 3600 20201116135527 20201019135527 1444 test. IZJIDmEgf0W7A5G7hvvZ2hUqJ9Trbv1/i7ySapDmPbYV9lVCmHHobySxO01yDhI2/Pvpsvxqrm1Tiv3BxH8uzZ4keKgiQjBsSy4htAsFct9I4E7ly2glPj/Fm3oun3PsjJDv5QYhx0KS7w4IQKU7Nc9pfJc92uoUI5bdoC1pRGw= +ns.test. 3600 IN NSEC nz.test. A RRSIG +ns.test. 3600 IN RRSIG NSEC 8 2 3600 20201116135527 20201019135527 1444 test. PElArVB3KPg8KHAP7lzcNbhFuXNxTsHNTn1dZVncB5qmWRdIaeKpaXDjpH0JSXMaelGFS+/QhuQ6Hmw9+4VyZFRqMzGhw4agUR/2bxABHcDIG4ZpUwyeSP61ATTfHUkQVxaH2wjCWI/tfmesdP2xVE4GXyUvCIBxU914MkZbULU= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +test. IN DNSKEY +SECTION ANSWER +test. 3600 IN DNSKEY 257 3 8 AwEAAbd9WqjzE2Pynz21OG5doSf9hFzMr5dhzz2waZ3vTa+0o5r7AjTAqmA1yH/B3+aAMihUm5ucZSfVqo7+kOaRE8yFj9aivOmA1n1+JLevJq/oyvQyjxQN2Qb89LyaNUT5oKZIiL+uyyhNW3KDR3SSbQ/GBwQNDHVcZi+JDR3RC0r7 ;{id = 1444 (ksk), size = 1024b} +test. 3600 IN RRSIG DNSKEY 8 1 3600 20201116135527 20201019135527 1444 test. UmRMS4iG9NBBHZYOtpwFFcJgbEb5SfHSgHd9XRe/8pTWM31WSDayn5ViPOBMqI1T5TXg2amc13dDI574xIM2oKMus3b5cBW72jJLW13jprBtslO6P8BMWb4HNnvLrJtQjwf3ErRirtTxinLmywQtmyr1cdthyG3Gp4N7i90fHSc= +SECTION ADDITIONAL +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qname qtype +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +example.test. IN DS +SECTION ANSWER +example.test. 3600 IN DS 55567 8 2 a2d578906330a10a57d40462257b6ce038bad3f7bf4a45c46c46086e20a94b39 +example.test. 3600 IN RRSIG DS 8 2 3600 20201116135527 20201019135527 1444 test. P7+FTYW2qHuJ4I1YbuvseEz5X1lOYAraGEHB3C5y0OOCQFmhmSiFRdquNi2NlpcS6FXLdsE0EU+Bo1+0atTG4EkMWXbpF21lrtbB51BdsnlX4Mzc/o375fvjiOMwmF6wPCUaOUN62jrVrhsE/hedaVyDphDToqL17ETohwgUO2I= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode subdomain +ADJUST copy_id copy_query +REPLY QR NOERROR +SECTION QUESTION +example.test. IN NS +SECTION AUTHORITY +example.test. IN NS ns.example.test. +example.test. 3600 IN DS 55567 8 2 a2d578906330a10a57d40462257b6ce038bad3f7bf4a45c46c46086e20a94b39 +example.test. 3600 IN RRSIG DS 8 2 3600 20201116135527 20201019135527 1444 test. P7+FTYW2qHuJ4I1YbuvseEz5X1lOYAraGEHB3C5y0OOCQFmhmSiFRdquNi2NlpcS6FXLdsE0EU+Bo1+0atTG4EkMWXbpF21lrtbB51BdsnlX4Mzc/o375fvjiOMwmF6wPCUaOUN62jrVrhsE/hedaVyDphDToqL17ETohwgUO2I= +SECTION ADDITIONAL +ns.example.test. IN A 1.2.3.4 +ENTRY_END + +ENTRY_BEGIN +MATCH opcode subdomain +ADJUST copy_id copy_query +REPLY QR NOERROR +SECTION QUESTION +fox.test. IN NS +SECTION AUTHORITY +fox.test. IN NS ns.fox.test. +fox.test. 3600 IN DS 29332 8 2 5b06f16c7b8cc07ba7b8e1ab0a40a40ecf89e1e94da2f0b1d2159b64dba80d96 +fox.test. 3600 IN RRSIG DS 8 2 3600 20201116135527 20201019135527 1444 test. B9bKqUJgJcGlKSWyGkdGGS6unKUwNJteTq08caL40QEZcAy836vwypGzOIQJNUw+mYIEecvtrF9H4mG+EjzDKv+n+36DCNvJMn6b8+FC9COw4mqITAjYPZjDwtOXAKVbuBuZJsbP2ztacJ98tXcORozaaKDGH/3fmsUlaKcuPmo= +SECTION ADDITIONAL +ns.fox.test. IN A 1.2.3.6 +ENTRY_END +RANGE_END + +; ns.example.test. +RANGE_BEGIN 0 15 + ADDRESS 1.2.3.4 +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR NOERROR +SECTION QUESTION +example.test. IN NS +SECTION ANSWER +example.test. IN NS ns.example.test. +example.test. 3600 IN RRSIG NS 8 2 3600 20201116135527 20201019135527 55567 example.test. l1JT0wMlK0YI7/CWHzexf/k0iafUhCgN+BdgjBXIRXmSQNf4HDTiAkbcWL2/15qtnp12nQy9JeiTdSQ3vtPoHAJX4C5uTWaze4ms+Wrrf+n92sLCjacP9x50uuicH3URT6cKb1QCAPwlvlWxIlZjAMYFScSns7+C441NMJT8aE4= +SECTION ADDITIONAL +ns.example.test. IN A 1.2.3.4 +ns.example.test. 3600 IN RRSIG A 8 3 3600 20201116135527 20201019135527 55567 example.test. 2PWaVaccZFQgfPKXNsdEGYUVaashCAj1ZhBo9XRt5eQKUFvZcauBjMnXIuxZFyWeootn1fZGw6GuPI5W48Y0FDx38H6adprkFgQikso2Y64jDdDMWznSo38Z/XqP+U0+kq4vmwonvmEMpm7hKnNEXvhqGKyGzyBwb+CZVJ2L8Eo= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +ns.example.test. IN A +SECTION ANSWER +ns.example.test. IN A 1.2.3.4 +ns.example.test. 3600 IN RRSIG A 8 3 3600 20201116135527 20201019135527 55567 example.test. 2PWaVaccZFQgfPKXNsdEGYUVaashCAj1ZhBo9XRt5eQKUFvZcauBjMnXIuxZFyWeootn1fZGw6GuPI5W48Y0FDx38H6adprkFgQikso2Y64jDdDMWznSo38Z/XqP+U0+kq4vmwonvmEMpm7hKnNEXvhqGKyGzyBwb+CZVJ2L8Eo= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +ns.example.test. IN AAAA +SECTION AUTHORITY +example.test. 3600 IN SOA ns.example.test. host.example.test. 20301 3600 1800 604800 3600 +example.test. 3600 IN RRSIG SOA 8 2 3600 20201116135527 20201019135527 55567 example.test. 2UUkScBAN37fJpSrelhE8DotKvmOzj3q9wicaanCIaCv95DE4nQnePih5B+ek3FIRjB/Uv2+z4Ro5Uxy94XAnlK0rCkDLSa0U9U7KP0ytc88sevO0x1SCPAMoZoJO6JqHkv42pdh54WSz+Zb/D8npY0j/tksHe/uX+VQnMymgb8= +ns.example.test. 3600 IN NSEC nz.example.test. A RRSIG +ns.example.test. 3600 IN RRSIG NSEC 8 3 3600 20201116135527 20201019135527 55567 example.test. v/5aO/n8Ow21y7LE7JKZsFkUJU5MjIfadVRm2Tdb8f3RLwYDdBTs3aWeeEQdCRSUF61TmfJM1jIxlWQPuHbqzGnjSk7adw9gFpP7wFwoqG3/xdCFHoxo/3/1F/4Ankey3sDgKgOFsgnu40TlL36mGPYszeK+/2o3SAx2GM+3BdU= +ENTRY_END + +; response to DNSKEY priming query +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR NOERROR +SECTION QUESTION +example.test. IN DNSKEY +SECTION ANSWER +example.test. 3600 IN DNSKEY 257 3 8 AwEAAdug/L739i0mgN2nuK/bhxu3wFn5Ud9nK2+XUmZQlPUEZUC5YZvm1rfMmEWTGBn87fFxEu/kjFZHJ55JLzqsbbpVHLbmKCTT2gYR2FV2WDKROGKuYbVkJIXdKAjJ0ONuK507NinYvlWXIoxHn22KAWOd9wKgSTNHBlmGkX+ts3hh ;{id = 55567 (ksk), size = 1024b} +example.test. 3600 IN RRSIG DNSKEY 8 2 3600 20201116135527 20201019135527 55567 example.test. IbWMC6quOuZFNPAVxQLqCJ9nLhindBo826rnLcg5yMgs9dGUSPOCXAfHTmbgJAUNs9HTFfrJWNvasnETs0UOpmEuifGwWdH1OlME7Gny4RL2QmITUFeMW81Jz1tiVQxFXl6yxT0jxOxvz+bqMHlrz+8IeWQXcO+GZTPu8ueq30g= +ENTRY_END + +; response to query of interest +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +a.d.example.test. IN A +SECTION ANSWER +d.example.test. 3600 IN DNAME tgt.example.test. +d.example.test. 3600 IN RRSIG DNAME 8 3 3600 20201116135527 20201019135527 55567 example.test. EGpXUnJuzkETAO2OWyZDrTeInnyxF7CXPXGDfFt2x3CBUeckUUZcgQQ3yMh+BATKph2nOhBfk8klvZ35C9sQO7Z32REAnqGjpHiR86xRPYxG62Nk9kXv1Odeh/adz2QhB93N8U7W57FM0P/VQDkP0GQXTSRGTuj+7ihfYVd4HWI= +; with CNAME signature +a.d.example.test. 3600 IN CNAME a.tgt.example.test. +a.d.example.test. 3600 IN RRSIG CNAME 8 4 3600 20201116135527 20201019135527 55567 example.test. efnytLE7P95kLr/tA9H0Z77VTOUQk24ci2bDgdVe8EuodTXtgg5PVHVLljD3QQ1Cpyme50odH/fhn2j1ORQpJTMk24Un/VRhVNquf+kj1nawJ59J0hjag4i0FIwZEG3/P7ogTB3Yd2y0Osb42Aawp48KvtVkUeBukk/GSutaTVQ= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +a.tgt.example.test. IN A +SECTION ANSWER +a.tgt.example.test. 3600 IN CNAME b.d.example.test. +a.tgt.example.test. 3600 IN RRSIG CNAME 8 4 3600 20201116135527 20201019135527 55567 example.test. XHYWSHIm9J8j8T1qMh1tHZS71UguXYUVescKPFtoGHRuyRhHNob+NAqdn3I4/+8HSSGrJDqhTX/Vo3rcc3/g5HOHScwzZByB/diyJWpG9IA7pm7c7FnHnHpGBVdHq9wXlkgCPiaJShpE1zg1nNy3p99ca9/wh4y9XWSfcl0L8aw= +ENTRY_END + +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +b.d.example.test. IN A +SECTION ANSWER +; This answer is injected +; Without an RRSIG. +b.d.example.test. 3600 IN CNAME www.fox.test. +ENTRY_END +RANGE_END + +; ns.fox.test. +RANGE_BEGIN 0 100 + ADDRESS 1.2.3.6 +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +ns.fox.test. IN AAAA +SECTION AUTHORITY +fox.test. 3600 IN SOA ns.fox.test. host.fox.test. 20601 3600 1800 604800 3600 +fox.test. 3600 IN RRSIG SOA 8 2 3600 20201116135527 20201019135527 29332 fox.test. QScf+vyis5/Km03ALuLQDfUDagA9/UG/oIQw6LnvmsVoqJSNXa3LIObWT9zfWgdJT0qFayWR4K9hnd9rT1enuVmXX8k47s7AjPZmE0qQxms5xz7jOhj/XLFplXOE9/GkgvAZKPb42qkU3Xf6Bevxzfy4/qW7+yXflWsjLV1vAhz38M4ESeWp0MDme8+DND0f7aoprGcC5saAPfa35nQhHS40q4IwiUDBBk1uwhCBF9ZGsjRfXmECOxIc1/0hBOv+Hhwog4K5b8rdl7LA2VggNiVOUuLFpXEH0XxknEspbQwWppP4TWC1H2QYGaKCc2Hu7NBhM/Ly7caGK+2u1MZvsg== +ns.fox.test. 3600 IN NSEC nz.fox.test. A RRSIG +ns.fox.test. 3600 IN RRSIG NSEC 8 3 3600 20201116135527 20201019135527 29332 fox.test. RQjV2PHbBVdGhvSRl0lutzoIZ9KezBAAwvI5sQoIGLdlMeQxj/BOy16auYRLTxvB9xehkrTTeL5xYUwcbi4uFS/kr3IUmlVXeldHOk4T42huV9MGfWzguUsB2jjsrcdt11qEnLo27SVVcvQReswwfpOPRPHg52fS6vt50AIWwttLOLvZEGiGIjRGb4lBaCnoO6YYzOnwcRCV0UScTjlPxS1SBEKsdbPvzfUUyp+wOVnIVAXrd0xEChB7QrTIrcBt4mutXVUNBDcfkZCXgEwu3scWQQS8rNO6O3PvpLgs6PIHX191WjovkJ9/PL+8MO/7UUatSWhZUwuQBUq6VofCYw== +ENTRY_END + +; response to DNSKEY priming query +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR NOERROR +SECTION QUESTION +fox.test. IN DNSKEY +SECTION ANSWER +fox.test. IN DNSKEY 257 3 8 AwEAAb4WMOTBLTFvmBra5m6SK4VfViOzmvyUAU0qv861ZQXeEFvwlndqNU9rwRsMxrSWAYs5nHErKDn49usC/HyxxW1477iGFHhfgL4mjNreJm9zft2QFB1VLbRbEPYdDMLCn4co0qnG7/KG8W2i8Pym1L7f+aREwbLo+/716AS2PbaKMhfWLKLiq5wnBcUClQMNzCiwhqxDJp1oePqfkVdeUgXOtgi0dYRIKyQFhJ5VWJ22npoi/Gif0XLCADAlAwRLKc8o/yJkCxskzgpHpw5Cki1lclg0aq4ssOuPRQ+ne6IHYCz9D2mwzulblhLFamKdq7aHzNt4NlyxhpANVFiKLD8= ;{id = 29332 (ksk), size = 2048b} +fox.test. 3600 IN RRSIG DNSKEY 8 2 3600 20201116135527 20201019135527 29332 fox.test. bTslCQKai9U9EWkBPnMiO+Rb34qMAZSzfgEb68x+ZKi2DDyzK7v8TCX8unTlqeQCnTqqgJ7cCUcqrbSV3ip9WGNe5fUy5j9hxH04ddLcDhygnjLi4C7iQX67ratRGu1JM3Evk/gVF76a5J2RSQk340jOFHC0nnjWOMHlDDxBeK4Zr6lYvAMJB2uy08xbi1FuGUSPcrbRFnVb74QMAPLS9Uj5JM8lMsOMtrhHX9zBN8Euo4M1X0sinBdJse3P/fIZ+ZvSnOEpVvur3bcUl+bqFJ18nM/Mj/e3XW3WBWE1dI6p6HdAXLrJyjJINzm+YnNzj11tzu/e4BQCjOutY9XkKA== +ENTRY_END + +; response to query of interest +ENTRY_BEGIN +MATCH opcode qtype qname +ADJUST copy_id +REPLY QR AA NOERROR +SECTION QUESTION +www.fox.test. IN A +SECTION ANSWER +www.fox.test. 3600 IN A 10.20.30.43 +www.fox.test. 3600 IN RRSIG A 8 3 3600 20201116135527 20201019135527 29332 fox.test. ehPLws7Jnlx5Trm7Z8Hxr0WkLdkxyif+E1aGzFMib4eP0nvLV89WOQ2Fpm1xT/VaNJBXjXhWPB0Oo/gAKVs1znqmyjutFdXi2+9rXnK73jD2+rWBGW/sgBl/9cr458j7441nEK18Mq4SserQcLBqM38IivTlK1J5uXUpEPKMCSA82waf0Z+LUk8czFqeYy+KlJSsiu33mrVWrjyNLIXCbZ2dxfdaVSKyAoQafiokp1NGnw3onQkXXOPqJ7GRsN8Ml4c2nOrEYIG6otoZXXjtkoNCOHzBBkPVEP82JjzQchq0fDWQ2UHOXXZYBG/B6m5PuOXmgKJVDKZ/iVNQofPp8w== +ENTRY_END +RANGE_END + +STEP 1 QUERY +ENTRY_BEGIN +REPLY RD DO +SECTION QUESTION +a.d.example.test. IN A +ENTRY_END + +STEP 10 TRAFFIC +; The unsigned CNAME should make SERVFAIL. + +STEP 20 CHECK_ANSWER +ENTRY_BEGIN +MATCH all +REPLY QR RD RA DO SERVFAIL +SECTION QUESTION +a.d.example.test. IN A +SECTION ANSWER +ENTRY_END + +SCENARIO_END diff --git a/validator/val_utils.c b/validator/val_utils.c index 1a5f19673..411a63b25 100644 --- a/validator/val_utils.c +++ b/validator/val_utils.c @@ -1334,3 +1334,26 @@ val_find_DS(struct module_env* env, uint8_t* nm, size_t nmlen, uint16_t c, env->scratch_buffer, *env->now, 0, topname, env->cfg); return msg; } + +int derive_cname_from_dname(struct ub_packed_rrset_key* cname, + struct ub_packed_rrset_key* dname, uint8_t* out, size_t outlen) +{ + size_t prefix_len; + uint8_t* dname_target = NULL; + size_t dname_target_len = 0; + if(!dname_strict_subdomain_c(cname->rk.dname, dname->rk.dname)) + return 0; /* Invalid: CNAME owner must be subdomain */ + get_cname_target(dname, &dname_target, &dname_target_len); + if(!dname_target || !dname_target_len) + return 0; /* DNAME malformed */ + if(cname->rk.dname_len < dname->rk.dname_len) + return 0; /* Not possible, due to subdomain, but check */ + if(cname->rk.dname_len == 0) + return 0; /* Not possible, but check */ + prefix_len = cname->rk.dname_len - dname->rk.dname_len; + if(prefix_len + dname_target_len > outlen) + return 0; /* Buffer too small */ + memmove(out, cname->rk.dname, prefix_len); + memmove(out+prefix_len, dname_target, dname_target_len); + return 1; +} diff --git a/validator/val_utils.h b/validator/val_utils.h index 4fe38c1bb..a584deea4 100644 --- a/validator/val_utils.h +++ b/validator/val_utils.h @@ -427,4 +427,15 @@ int val_favorite_ds_algo(struct ub_packed_rrset_key* ds_rrset); struct dns_msg* val_find_DS(struct module_env* env, uint8_t* nm, size_t nmlen, uint16_t c, struct regional* region, uint8_t* topname); +/** + * Derive expected CNAME target from DNAME substitution per RFC 6672 s3.1 + * @param cname: CNAME RRset, (e.g., b.d.a005.test CNAME ) + * @param dname: DNAME RRset, (e.g., d.a005.test DNAME tgt.a005.test) + * @param out: Output buffer for expected CNAME target + * @param outlen: Output buffer size + * @return: 1 on success, 0 on error + */ +int derive_cname_from_dname(struct ub_packed_rrset_key* cname, + struct ub_packed_rrset_key* dname, uint8_t* out, size_t outlen); + #endif /* VALIDATOR_VAL_UTILS_H */ diff --git a/validator/validator.c b/validator/validator.c index d6f57bcc9..b3d55f075 100644 --- a/validator/validator.c +++ b/validator/validator.c @@ -710,6 +710,37 @@ validate_msg_signatures(struct module_qstate* qstate, struct val_qstate* vq, ((struct packed_rrset_data*)chase_reply->rrsets[i-1]->entry.data)->security == sec_status_secure && dname_strict_subdomain_c(s->rk.dname, chase_reply->rrsets[i-1]->rk.dname) ) { + /* Check that the CNAME target matches the DNAME + * derivation. Zone changes during the redirection + * lookups or looped DNAMEs can have such a CNAME. */ + uint8_t expected_target[LDNS_MAX_DOMAINLEN]; + uint8_t* cname_target = NULL; + size_t cname_target_len = 0; + get_cname_target(s, &cname_target, &cname_target_len); + if(!cname_target || + !derive_cname_from_dname(s, /* CNAME RRset */ + chase_reply->rrsets[i-1], /* DNAME RRset */ + expected_target, /* Output buffer */ + sizeof(expected_target))) { + verbose(VERB_ALGO, "DNAME CNAME derivation failed"); + errinf_ede(qstate, "DNAME CNAME derivation failed", reason_bogus); + errinf_origin(qstate, qstate->reply_origin); + chase_reply->security = sec_status_bogus; + update_reason_bogus(chase_reply, reason_bogus); + return 0; + } + if(query_dname_compare(cname_target, expected_target) != 0) { + verbose(VERB_ALGO, "CNAME target mismatch: not synthesized from DNAME"); + errinf_ede(qstate, "CNAME target mismatch: not synthesized from DNAME", reason_bogus); + errinf_dname(qstate, ", for", s->rk.dname); + errinf_dname(qstate, "CNAME", cname_target); + errinf(qstate, ","); + errinf_origin(qstate, qstate->reply_origin); + chase_reply->security = sec_status_bogus; + update_reason_bogus(chase_reply, reason_bogus); + return 0; + } + /* CNAME was synthesized by our own iterator */ /* since the DNAME verified, mark the CNAME as secure */ ((struct packed_rrset_data*)s->entry.data)->security =