[PATCH 1/1] selftests: net: fix file owner for broadcast_ether_dst test

[Ross Porter]

Ensure the output file is always owned by root (even if tcpdump was 
compiled with `--with-user`), by passing the `-Z root` argument when 
invoking it.

Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Edoardo Canepa <edoardo.canepa@xxxxxxxxxxxxx>
Closes: https://bugs.launchpad.net/ubuntu-kernel-tests/+bug/2129815
Fixes: bf59028ea8d4 ("selftests: net: add test for destination in broadcast packets")
Suggested-by: Edoardo Canepa <edoardo.canepa@xxxxxxxxxxxxx>
Tested-by: Ross Porter <ross.porter@xxxxxxxxxxxxx>
Signed-off-by: Ross Porter <ross.porter@xxxxxxxxxxxxx>
---
 tools/testing/selftests/net/broadcast_ether_dst.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/broadcast_ether_dst.sh b/tools/testing/selftests/net/broadcast_ether_dst.sh
index 334a7eca8a80..5e7a8fe23c7a 100755
--- a/tools/testing/selftests/net/broadcast_ether_dst.sh
+++ b/tools/testing/selftests/net/broadcast_ether_dst.sh
@@ -44,7 +44,7 @@ test_broadcast_ether_dst() {
 	# tcpdump will exit after receiving a single packet
 	# timeout will kill tcpdump if it is still running after 2s
 	timeout 2s ip netns exec "${CLIENT_NS}" \
-		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp &> "${OUTPUT}" &
+		tcpdump -i link0 -c 1 -w "${CAPFILE}" icmp -Z root &> "${OUTPUT}" &
 	pid=$!
 	slowwait 1 grep -qs "listening" "${OUTPUT}"
 
-- 
2.53.0