mnl: Improve error checking in mnl_nft_event_listener()

When trying to adjust receive buffer size, the second call to
setsockopt() was not error-checked.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/mnl.c b/src/mnl.c
index 2be8ca14..0d9b7ffc 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -1425,8 +1425,11 @@ int mnl_nft_event_listener(struct mnl_socket *nf_sock, unsigned int debug_mask,
 		 */
 		ret = setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &bufsiz,
 				 sizeof(socklen_t));
-		nft_print(octx, "# Cannot set up netlink socket buffer size to %u bytes, falling back to %u bytes\n",
-			  NFTABLES_NLEVENT_BUFSIZ, bufsiz);
+		if (ret < 0)
+			nft_print(octx, "# Cannot increase netlink socket buffer size, expect message loss\n");
+		else
+			nft_print(octx, "# Cannot set up netlink socket buffer size to %u bytes, falling back to %u bytes\n",
+				  NFTABLES_NLEVENT_BUFSIZ, bufsiz);
 	}
 
 	while (1) {