[oe][meta-networking][scarthgap][PATCH 1/2] dnsmasq: Fix CVE-2026-12725

From: Darsh Kelaiya <[email protected]>

This patch applies the upstream fix for CVE-2026-12725 as referenced
in [2], using the upstream commit identified in [1].

[1] https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=36d081e37477027fd721fea498f3760f529034ad
[2] https://security-tracker.debian.org/tracker/CVE-2026-12725

Signed-off-by: Darsh Kelaiya <[email protected]>
---
 .../recipes-support/dnsmasq/dnsmasq_2.90.bb   |   1 +
 .../dnsmasq/files/CVE-2026-12725.patch        | 111 ++++++++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 meta-networking/recipes-support/dnsmasq/files/CVE-2026-12725.patch

diff --git a/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb b/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb
index 3a7af56c34..c25c25a447 100644
--- a/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb
+++ b/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb
@@ -21,6 +21,7 @@ SRC_URI = "http://www.thekelleys.org.uk/dnsmasq/${@['archive/', ''][float(d.getV
            file://CVE-2026-4893.patch \
            file://CVE-2026-5172.patch \
            file://CVE-2026-2291.patch \
+           file://CVE-2026-12725.patch \
 "
 SRC_URI[sha256sum] = "8f6666b542403b5ee7ccce66ea73a4a51cf19dd49392aaccd37231a2c51b303b"
 
diff --git a/meta-networking/recipes-support/dnsmasq/files/CVE-2026-12725.patch b/meta-networking/recipes-support/dnsmasq/files/CVE-2026-12725.patch
new file mode 100644
index 0000000000..191bfc9595
--- /dev/null
+++ b/meta-networking/recipes-support/dnsmasq/files/CVE-2026-12725.patch
@@ -0,0 +1,111 @@
+From 85a8577cc28751a2337275e566a9e29b8e8d8403 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <[email protected]>
+Date: Tue, 21 Apr 2026 22:14:41 +0100
+Subject: [PATCH] Fix buffer overlow in log_query()
+
+The addition of "(not supported)" to logs of DS and DNSKEY replies
+overflows the buffer used to construct the string.
+
+Re-arrange things to avoid this, and add checks to avoid the same  problem
+if the logging calls change in the future.
+
+Thanks to Yiwei Hou for finding this.
+
+The problem exists is DNSSEC is enabled and query logging is also
+enabled. The overwrite is of bounded length and the bytes
+written are not in control of an attacker, so this is not considered
+a likely remote-execution vector.
+
+CVE: CVE-2026-12725
+Upstream-Status: Backport [https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=36d081e37477027fd721fea498f3760f529034ad]
+
+Backport Changes:
+- dnsmasq 2.90 predates upstream commit 9e67099ce73c, which added
+  F_QUERY to the log_query() type-string exclusion mask. Preserve the
+  existing 2.90 F_QUERY logging behavior and add only the
+  security-relevant F_KEYTAG and F_RR exclusions.
+
+(cherry picked from commit 36d081e37477027fd721fea498f3760f529034ad)
+Signed-off-by: Darsh Kelaiya <[email protected]>
+---
+ src/cache.c  | 28 +++++++++++++++++-----------
+ src/dnssec.c |  7 ++-----
+ 2 files changed, 19 insertions(+), 16 deletions(-)
+
+diff --git a/src/cache.c b/src/cache.c
+index 0eacec9..5f92520 100644
+--- a/src/cache.c
++++ b/src/cache.c
+@@ -2104,7 +2104,7 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
+     return;
+ 
+   /* build query type string if requested */
+-  if (!(flags & (F_SERVER | F_IPSET)) && type > 0)
++  if (!(flags & (F_SERVER | F_IPSET | F_KEYTAG | F_RR)) && type > 0)
+     arg = querystr(arg, type);
+ 
+   dest = arg;
+@@ -2120,19 +2120,25 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
+     {
+       dest = daemon->addrbuff;
+ 
+-       if (flags & F_RR)
+-	 {
+-	   if (flags & F_KEYTAG)
+-	     dest = querystr(NULL, addr->rrblock.rrtype);
+-	   else
+-	     dest = querystr(NULL, addr->rrdata.rrtype);
+-	 }
+-       else if (flags & F_KEYTAG)
+-	sprintf(daemon->addrbuff, arg, addr->log.keytag, addr->log.algo, addr->log.digest);
++      if (flags & F_RR)
++	{
++	  if (flags & F_KEYTAG)
++	    dest = querystr(NULL, addr->rrblock.rrtype);
++	  else
++	    dest = querystr(NULL, addr->rrdata.rrtype);
++	}
++#ifdef HAVE_DNSSEC
++      else if (flags & F_KEYTAG)
++	{
++	  snprintf(daemon->addrbuff, ADDRSTRLEN, arg, addr->log.keytag, addr->log.algo, addr->log.digest);
++	  if (type)
++	    extra = " (not supported)";
++	}
++#endif
+       else if (flags & F_RCODE)
+ 	{
+ 	  unsigned int rcode = addr->log.rcode;
+-
++	  
+ 	  if (rcode == SERVFAIL)
+ 	    dest = "SERVFAIL";
+ 	  else if (rcode == REFUSED)
+diff --git a/src/dnssec.c b/src/dnssec.c
+index bdd48ca..28c07dd 100644
+--- a/src/dnssec.c
++++ b/src/dnssec.c
+@@ -953,10 +953,7 @@ int dnssec_validate_by_ds(time_t now, struct dns_header *header, size_t plen, ch
+ 			   
+ 			   a.log.keytag = keytag;
+ 			   a.log.algo = algo;
+-			   if (algo_digest_name(algo))
+-			     log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu", 0);
+-			   else
+-			     log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu (not supported)", 0);
++			   log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu", !algo_digest_name(algo));
+ 			 }
+ 		     }
+ 				  
+@@ -1082,7 +1079,7 @@ int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char
+ 		  a.log.keytag = keytag;
+ 		  a.log.algo = algo;
+ 		  a.log.digest = digest;
+-		  log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DS for keytag %hu, algo %hu, digest %hu (not supported)", 0);
++		  log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DS for keytag %hu, algo %hu, digest %hu", 1);
+ 		  neg_ttl = ttl;
+ 		} 
+ 	      else if ((key = blockdata_alloc((char*)p, rdlen - 4)))
+-- 
+2.44.4
+
-- 
2.35.6