dnsmasq: fix CVE-2023-28450

The patch is modified by removing irrelevant and conflicting
CHANGELOG entry.

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

2 files changed, 49 insertions, 0 deletions

diff --git a/meta-networking/recipes-support/dnsmasq/dnsmasq.inc b/meta-networking/recipes-support/dnsmasq/dnsmasq.inc
index a8ff21a125..9e0f529ec1 100644
--- a/meta-networking/recipes-support/dnsmasq/dnsmasq.inc
+++ b/meta-networking/recipes-support/dnsmasq/dnsmasq.inc
@@ -14,6 +14,7 @@ SRC_URI = "http://www.thekelleys.org.uk/dnsmasq/${@['archive/', ''][float(d.getV
            file://dnsmasq-resolvconf.service \
            file://dnsmasq-noresolvconf.service \
            file://dnsmasq-resolved.conf \
+           file://CVE-2023-28450.patch \
 "
 
 inherit pkgconfig update-rc.d systemd
diff --git a/meta-networking/recipes-support/dnsmasq/files/CVE-2023-28450.patch b/meta-networking/recipes-support/dnsmasq/files/CVE-2023-28450.patch
new file mode 100644
index 0000000000..129c9043e8
--- /dev/null
+++ b/meta-networking/recipes-support/dnsmasq/files/CVE-2023-28450.patch
@@ -0,0 +1,48 @@
+From eb92fb32b746f2104b0f370b5b295bb8dd4bd5e5 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Tue, 7 Mar 2023 22:07:46 +0000
+Subject: [PATCH] Set the default maximum DNS UDP packet size to 1232.
+
+http://www.dnsflagday.net/2020/ refers.
+
+Thanks to Xiang Li for the prompt.
+
+CVE: CVE-2023-28450
+Upstream-Status: Backport [https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=eb92fb32b746f2104b0f370b5b295bb8dd4bd5e5]
+
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ man/dnsmasq.8 | 3 ++-
+ src/config.h  | 2 +-
+ 2 files changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/man/dnsmasq.8 b/man/dnsmasq.8
+index 41e2e04..5acb935 100644
+--- a/man/dnsmasq.8
++++ b/man/dnsmasq.8
+@@ -183,7 +183,8 @@ to zero completely disables DNS function, leaving only DHCP and/or TFTP.
+ .TP
+ .B \-P, --edns-packet-max=<size>
+ Specify the largest EDNS.0 UDP packet which is supported by the DNS
+-forwarder. Defaults to 4096, which is the RFC5625-recommended size.
++forwarder. Defaults to 1232, which is the recommended size following the
++DNS flag day in 2020. Only increase if you know what you are doing.
+ .TP
+ .B \-Q, --query-port=<query_port>
+ Send outbound DNS queries from, and listen for their replies on, the
+diff --git a/src/config.h b/src/config.h
+index 1e7b30f..37b374e 100644
+--- a/src/config.h
++++ b/src/config.h
+@@ -19,7 +19,7 @@
+ #define CHILD_LIFETIME 150 /* secs 'till terminated (RFC1035 suggests > 120s) */
+ #define TCP_MAX_QUERIES 100 /* Maximum number of queries per incoming TCP connection */
+ #define TCP_BACKLOG 32  /* kernel backlog limit for TCP connections */
+-#define EDNS_PKTSZ 4096 /* default max EDNS.0 UDP packet from RFC5625 */
++#define EDNS_PKTSZ 1232 /* default max EDNS.0 UDP packet from from  /dnsflagday.net/2020 */
+ #define SAFE_PKTSZ 1232 /* "go anywhere" UDP packet size, see https://dnsflagday.net/2020/ */
+ #define KEYBLOCK_LEN 40 /* choose to minimise fragmentation when storing DNSSEC keys */
+ #define DNSSEC_WORK 50 /* Max number of queries to validate one question */
+-- 
+2.20.1
+