- 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.
This commit is contained in:
W.C.A. Wijngaards
2026-04-21 13:19:13 +02:00
parent c112bcf2fd
commit 8a25a97687
5 changed files with 367 additions and 0 deletions
+5
View File
@@ -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.
+297
View File
@@ -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
+23
View File
@@ -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;
}
+11
View File
@@ -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 <some cname target>)
* @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 */
+31
View File
@@ -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 =