examples: genl: fix wrong attribute size

This example no longer works on more recent kernels:

genl-family-get
error: Invalid argument

dmesg says:
netlink: 'genl-family-get': attribute type 1 has an invalid length.

Fix this and also zero out the reserved field in the genl header,
while not validated yet for dumps this could change.

Upstream-Status: Backport [https://git.netfilter.org/libmnl/patch/?id=54dea548d796653534645c6e3c8577eaf7d77411]

Reported-by: Divyanshu Rathore <Divyanshu.Rathore@bmwtechworks.in>
(From OE-Core rev: bae5ecea1c40847ffc3760173192f85e28ed9d7b)

Signed-off-by: Florian Westphal <fw@strlen.de>
(cherry picked from commit 54dea548d796653534645c6e3c8577eaf7d77411)
Signed-off-by: Divyanshu Rathore <divyanshu.rathore@bmwtechworks.in>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 48 insertions, 1 deletions

diff --git a/meta/recipes-extended/libmnl/files/0001-examples-genl-fix-wrong-attribute-size.patch b/meta/recipes-extended/libmnl/files/0001-examples-genl-fix-wrong-attribute-size.patch
new file mode 100644
index 0000000000..9e06abb9a4
--- /dev/null
+++ b/meta/recipes-extended/libmnl/files/0001-examples-genl-fix-wrong-attribute-size.patch
@@ -0,0 +1,44 @@
+From 67ad7abf1fe888c650f9e8ed326a499e1456285c Mon Sep 17 00:00:00 2001
+From: Florian Westphal <fw@strlen.de>
+Date: Mon, 15 Sep 2025 14:40:30 +0200
+Subject: [PATCH] examples: genl: fix wrong attribute size
+
+This example no longer works on more recent kernels:
+
+genl-family-get
+error: Invalid argument
+
+dmesg says:
+netlink: 'genl-family-get': attribute type 1 has an invalid length.
+
+Fix this and also zero out the reserved field in the genl header,
+while not validated yet for dumps this could change.
+
+Upstream-Status: Backport [https://git.netfilter.org/libmnl/patch/?id=54dea548d796653534645c6e3c8577eaf7d77411]
+
+Reported-by: Divyanshu Rathore <Divyanshu.Rathore@bmwtechworks.in>
+Signed-off-by: Florian Westphal <fw@strlen.de>
+(cherry picked from commit 54dea548d796653534645c6e3c8577eaf7d77411)
+Signed-off-by: Divyanshu Rathore <divyanshu.rathore@bmwtechworks.in>
+---
+ examples/genl/genl-family-get.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/examples/genl/genl-family-get.c b/examples/genl/genl-family-get.c
+index ba8de12..0c20067 100644
+--- a/examples/genl/genl-family-get.c
++++ b/examples/genl/genl-family-get.c
+@@ -199,8 +199,9 @@ int main(int argc, char *argv[])
+        genl = mnl_nlmsg_put_extra_header(nlh, sizeof(struct genlmsghdr));
+        genl->cmd = CTRL_CMD_GETFAMILY;
+        genl->version = 1;
++       genl->reserved = 0;
+ 
+-       mnl_attr_put_u32(nlh, CTRL_ATTR_FAMILY_ID, GENL_ID_CTRL);
++       mnl_attr_put_u16(nlh, CTRL_ATTR_FAMILY_ID, GENL_ID_CTRL);
+        if (argc >= 2)
+                mnl_attr_put_strz(nlh, CTRL_ATTR_FAMILY_NAME, argv[1]);
+        else
+-- 
+2.34.1
+
diff --git a/meta/recipes-extended/libmnl/libmnl_1.0.5.bb b/meta/recipes-extended/libmnl/libmnl_1.0.5.bb
index 66b30d7f60..d0bf658eef 100644
--- a/meta/recipes-extended/libmnl/libmnl_1.0.5.bb
+++ b/meta/recipes-extended/libmnl/libmnl_1.0.5.bb
@@ -6,7 +6,10 @@ SECTION = "libs"
 LICENSE = "LGPL-2.1-or-later"
 LIC_FILES_CHKSUM = "file://COPYING;md5=4fbd65380cdd255951079008b364516c"
 
-SRC_URI = "https://netfilter.org/projects/libmnl/files/libmnl-${PV}.tar.bz2"
+SRC_URI = "https://netfilter.org/projects/libmnl/files/libmnl-${PV}.tar.bz2 \
+           file://0001-examples-genl-fix-wrong-attribute-size.patch \
+"
+
 SRC_URI[sha256sum] = "274b9b919ef3152bfb3da3a13c950dd60d6e2bcd54230ffeca298d03b40d0525"
 
 inherit autotools pkgconfig