From afdbb0204a5872f1f76058a0db5a529b1f0c8de7 Mon Sep 17 00:00:00 2001
From: Benjamin Poirier <bpoirier@nvidia.com>
Date: Mon, 11 Jul 2022 08:52:52 +0900
Subject: [PATCH] mptcp: Fix memory leak when doing 'endpoint show'

With the following command sequence:

ip mptcp endpoint add 127.0.0.1 id 1
ip mptcp endpoint show id 1

when running the last command under valgrind, it reports

32,768 bytes in 1 blocks are definitely lost in loss record 2 of 2
at 0x483F7B5: malloc (vg_replace_malloc.c:381)
by 0x17A0AC: rtnl_recvmsg (libnetlink.c:838)
by 0x17A391: __rtnl_talk_iov.constprop.0 (libnetlink.c:1040)
by 0x17B854: __rtnl_talk (libnetlink.c:1141)
by 0x17B854: rtnl_talk (libnetlink.c:1147)
by 0x168A56: mptcp_addr_show (ipmptcp.c:334)
by 0x1174CB: do_cmd (ip.c:136)
by 0x116F7C: main (ip.c:324)

Free the answer obtained from rtnl_talk().

Fixes: 7e0767cd862b ("add support for mptcp netlink interface")
Suggested-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Conflict: adapt patch due to json_xxx conflict
Reference: https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/commit?id=afdbb020
---
ip/ipmptcp.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/ip/ipmptcp.c b/ip/ipmptcp.c
index fd042da..763908f 100644
--- a/ip/ipmptcp.c
+++ b/ip/ipmptcp.c
@@ -299,7 +299,9 @@ static int mptcp_addr_show(int argc, char **argv)
 	if (rtnl_talk(&genl_rth, &req.n, &answer) < 0)
 		return -2;
 
-	return print_mptcp_addr(answer, stdout);
+	ret = print_mptcp_addr(answer, stdout);
+	free(answer);
+	return ret;
 }
 
 static int mptcp_addr_flush(int argc, char **argv)