From 88f3b8366ba8b7272e3e0b4c901a9aab75c9304a Mon Sep 17 00:00:00 2001 From: Thomas Perale Date: Fri, 26 Jun 2026 21:59:37 +0200 Subject: [PATCH] package/avahi: upstream patch for CVE-2026-34933 This fixes the following vulnerability: - CVE-2026-34933: Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. Prior to version 0.9-rc4, any unprivileged local user can crash avahi-daemon by sending a single D-Bus method call with conflicting publish flags. This issue has been patched in version 0.9-rc4. For more information, see: - https://www.cve.org/CVERecord?id=CVE-2026-34933 - https://github.com/avahi/avahi/commit/0be89b6bb5c3983837b5e0febcbbbf452ecf7675 Signed-off-by: Thomas Perale Signed-off-by: Julien Olivain --- ...both-wide-area-and-multicast-are-set.patch | 106 ++++++++++++++++++ package/avahi/avahi.mk | 3 + 2 files changed, 109 insertions(+) create mode 100644 package/avahi/0017-core-refuse-to-accept-publish-flags-where-both-wide-area-and-multicast-are-set.patch diff --git a/package/avahi/0017-core-refuse-to-accept-publish-flags-where-both-wide-area-and-multicast-are-set.patch b/package/avahi/0017-core-refuse-to-accept-publish-flags-where-both-wide-area-and-multicast-are-set.patch new file mode 100644 index 0000000000..de359b7d22 --- /dev/null +++ b/package/avahi/0017-core-refuse-to-accept-publish-flags-where-both-wide-area-and-multicast-are-set.patch @@ -0,0 +1,106 @@ +From 0be89b6bb5c3983837b5e0febcbbbf452ecf7675 Mon Sep 17 00:00:00 2001 +From: Evgeny Vereshchagin +Date: Wed, 1 Apr 2026 05:31:58 +0000 +Subject: [PATCH] core: refuse to accept publish flags where both wide_area and + multicast are set + +It fixes a bug where it was possible for unprivileged local users to +crash avahi-daemon via D-Bus by calling EntryGroup methods accepting +flags and passing both AVAHI_PUBLISH_USE_WIDE_AREA and +AVAHI_PUBLISH_USE_MULTICAST there. For example when AddRecord was +invoked like that avahi-daemon crashed with +``` +dbus-entry-group.c: interface=org.freedesktop.Avahi.EntryGroup, path=/Client0/EntryGroup1, member=AddRecord +avahi-daemon: entry.c:57: transport_flags_from_domain: Assertion `!((*flags & AVAHI_PUBLISH_USE_MULTICAST) && (*flags & AVAHI_PUBLISH_USE_WIDE_AREA))' failed. +==84944== +==84944== Process terminating with default action of signal 6 (SIGABRT) +==84944== at 0x4B353BC: __pthread_kill_implementation (pthread_kill.c:44) +==84944== by 0x4ADE941: raise (raise.c:26) +==84944== by 0x4AC64AB: abort (abort.c:77) +==84944== by 0x4AC641F: __assert_fail_base.cold (assert.c:118) +==84944== by 0x48A9404: transport_flags_from_domain (entry.c:57) +==84944== by 0x48A9F8F: server_add_internal (entry.c:224) +==84944== by 0x48AA49F: avahi_server_add (entry.c:324) +==84944== by 0x401A670: avahi_dbus_msg_entry_group_impl (dbus-entry-group.c:348) +==84944== by 0x4A70741: ??? (in /usr/lib/x86_64-linux-gnu/libdbus-1.so.3.38.3) +==84944== by 0x4A5FB22: dbus_connection_dispatch (in /usr/lib/x86_64-linux-gnu/libdbus-1.so.3.38.3) +==84944== by 0x401D01D: dispatch_timeout_callback (dbus-watch-glue.c:105) +==84944== by 0x488E3AE: timeout_callback (simple-watch.c:447) +==84944== +``` +It's a follow-up to fbce111b069aa1e4c701ed37ee1d9f6d6cefaac5 where +those flags were introduced and consistent with the other places +where wide_area/multicast flags are used. + +It was discovered by +Guillaume Meunier - Head of Vulnerability Operations Center France - Orange Cyberdefense + +https://github.com/avahi/avahi/security/advisories/GHSA-w65r-6gxh-vhvc + +CVE: CVE-2026-34933 +Upstream: https://github.com/avahi/avahi/commit/0be89b6bb5c3983837b5e0febcbbbf452ecf7675 +Signed-off-by: Thomas Perale +--- + avahi-core/entry.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +diff --git a/avahi-core/entry.c b/avahi-core/entry.c +index 0d862133d..06eb12076 100644 +--- a/avahi-core/entry.c ++++ b/avahi-core/entry.c +@@ -207,6 +207,7 @@ static AvahiEntry * server_add_internal( + AVAHI_PUBLISH_UPDATE| + AVAHI_PUBLISH_USE_WIDE_AREA| + AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); ++ AVAHI_CHECK_VALIDITY_RETURN_NULL(s, !(flags & AVAHI_PUBLISH_USE_WIDE_AREA) || !(flags & AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY_RETURN_NULL(s, avahi_is_valid_domain_name(r->key->name), AVAHI_ERR_INVALID_HOST_NAME); + AVAHI_CHECK_VALIDITY_RETURN_NULL(s, r->ttl != 0, AVAHI_ERR_INVALID_TTL); + AVAHI_CHECK_VALIDITY_RETURN_NULL(s, !avahi_key_is_pattern(r->key), AVAHI_ERR_IS_PATTERN); +@@ -454,6 +455,7 @@ int avahi_server_add_address( + AVAHI_PUBLISH_UPDATE| + AVAHI_PUBLISH_USE_WIDE_AREA| + AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); ++ AVAHI_CHECK_VALIDITY(s, !(flags & AVAHI_PUBLISH_USE_WIDE_AREA) || !(flags & AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY(s, !name || avahi_is_valid_fqdn(name), AVAHI_ERR_INVALID_HOST_NAME); + + /* Prepare the host naem */ +@@ -595,6 +597,7 @@ static int server_add_service_strlst_nocopy( + AVAHI_PUBLISH_UPDATE| + AVAHI_PUBLISH_USE_WIDE_AREA| + AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); ++ AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, !(flags & AVAHI_PUBLISH_USE_WIDE_AREA) || !(flags & AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, avahi_is_valid_service_name(name), AVAHI_ERR_INVALID_SERVICE_NAME); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, avahi_is_valid_service_type_strict(type), AVAHI_ERR_INVALID_SERVICE_TYPE); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, !domain || avahi_is_valid_domain_name(domain), AVAHI_ERR_INVALID_DOMAIN_NAME); +@@ -754,6 +757,7 @@ static int server_update_service_txt_strlst_nocopy( + AVAHI_PUBLISH_NO_COOKIE| + AVAHI_PUBLISH_USE_WIDE_AREA| + AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); ++ AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, !(flags & AVAHI_PUBLISH_USE_WIDE_AREA) || !(flags & AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, avahi_is_valid_service_name(name), AVAHI_ERR_INVALID_SERVICE_NAME); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, avahi_is_valid_service_type_strict(type), AVAHI_ERR_INVALID_SERVICE_TYPE); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, !domain || avahi_is_valid_domain_name(domain), AVAHI_ERR_INVALID_DOMAIN_NAME); +@@ -843,6 +847,7 @@ int avahi_server_add_service_subtype( + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, AVAHI_IF_VALID(interface), AVAHI_ERR_INVALID_INTERFACE); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, AVAHI_PROTO_VALID(protocol), AVAHI_ERR_INVALID_PROTOCOL); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, AVAHI_FLAGS_VALID(flags, AVAHI_PUBLISH_USE_MULTICAST|AVAHI_PUBLISH_USE_WIDE_AREA), AVAHI_ERR_INVALID_FLAGS); ++ AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, !(flags & AVAHI_PUBLISH_USE_WIDE_AREA) || !(flags & AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, avahi_is_valid_service_name(name), AVAHI_ERR_INVALID_SERVICE_NAME); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, avahi_is_valid_service_type_strict(type), AVAHI_ERR_INVALID_SERVICE_TYPE); + AVAHI_CHECK_VALIDITY_SET_RET_GOTO_FAIL(s, !domain || avahi_is_valid_domain_name(domain), AVAHI_ERR_INVALID_DOMAIN_NAME); +@@ -910,6 +915,7 @@ static AvahiEntry *server_add_dns_server_name( + assert(name); + + AVAHI_CHECK_VALIDITY_RETURN_NULL(s, AVAHI_FLAGS_VALID(flags, AVAHI_PUBLISH_USE_WIDE_AREA|AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); ++ AVAHI_CHECK_VALIDITY_RETURN_NULL(s, !(flags & AVAHI_PUBLISH_USE_WIDE_AREA) || !(flags & AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY_RETURN_NULL(s, type == AVAHI_DNS_SERVER_UPDATE || type == AVAHI_DNS_SERVER_RESOLVE, AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY_RETURN_NULL(s, port != 0, AVAHI_ERR_INVALID_PORT); + AVAHI_CHECK_VALIDITY_RETURN_NULL(s, avahi_is_valid_fqdn(name), AVAHI_ERR_INVALID_HOST_NAME); +@@ -967,6 +973,7 @@ int avahi_server_add_dns_server_address( + AVAHI_CHECK_VALIDITY(s, AVAHI_IF_VALID(interface), AVAHI_ERR_INVALID_INTERFACE); + AVAHI_CHECK_VALIDITY(s, AVAHI_PROTO_VALID(protocol) && AVAHI_PROTO_VALID(address->proto), AVAHI_ERR_INVALID_PROTOCOL); + AVAHI_CHECK_VALIDITY(s, AVAHI_FLAGS_VALID(flags, AVAHI_PUBLISH_USE_MULTICAST|AVAHI_PUBLISH_USE_WIDE_AREA), AVAHI_ERR_INVALID_FLAGS); ++ AVAHI_CHECK_VALIDITY(s, !(flags & AVAHI_PUBLISH_USE_WIDE_AREA) || !(flags & AVAHI_PUBLISH_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY(s, type == AVAHI_DNS_SERVER_UPDATE || type == AVAHI_DNS_SERVER_RESOLVE, AVAHI_ERR_INVALID_FLAGS); + AVAHI_CHECK_VALIDITY(s, port != 0, AVAHI_ERR_INVALID_PORT); + AVAHI_CHECK_VALIDITY(s, !domain || avahi_is_valid_domain_name(domain), AVAHI_ERR_INVALID_DOMAIN_NAME); diff --git a/package/avahi/avahi.mk b/package/avahi/avahi.mk index bcba0a0a4f..0a674182bc 100644 --- a/package/avahi/avahi.mk +++ b/package/avahi/avahi.mk @@ -60,6 +60,9 @@ AVAHI_IGNORE_CVES += CVE-2025-68471 # 0016-core-fix-uncontrolled-recursion-bug-using-a-simple-loop-detection-algorithm.patch AVAHI_IGNORE_CVES += CVE-2026-24401 +# 0017-core-refuse-to-accept-publish-flags-where-both-wide-area-and-multicast-are-set.patch +AVAHI_IGNORE_CVES += CVE-2026-34933 + AVAHI_CONF_ENV = \ avahi_cv_sys_cxx_works=yes \ DATADIRNAME=share