Subject: [PATCH 26/31] ipv6: release dst in ping_v6_sendmsg

From: Dave Jones <[email-masked]>
Date: Fri, 2 Sep 2016 14:39:50 -0400

[ Upstream commit 03c2778a938aaba0893f6d6cdc29511d91a79848 ]

Neither the failure or success paths of ping_v6_sendmsg release
the dst it acquires.  This leads to a flood of warnings from
"net/core/dst.c:288 dst_release" on older kernels that
don't have 8bf4ada2e21378816b28205427ee6b0e1ca4c5f1 backported.

That patch optimistically hoped this had been fixed post 3.10, but
it seems at least one case wasn't, where I've seen this triggered
a lot from machines doing unprivileged icmp sockets.

Cc: Martin Lau <[email-masked]>
Signed-off-by: Dave Jones <[email-masked]>
Acked-by: Martin KaFai Lau <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/ipv6/ping.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index 3ee3e44..4086604 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -122,8 +122,10 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	rt = (struct rt6_info *) dst;
 
 	np = inet6_sk(sk);
-	if (!np)
-		return -EBADF;
+	if (!np) {
+		err = -EBADF;
+		goto dst_err_out;
+	}
 
 	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 		fl6.flowi6_oif = np->mcast_oif;
@@ -160,6 +162,9 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	}
 	release_sock(sk);
 
+dst_err_out:
+	dst_release(dst);
+
 	if (err)
 		return err;
 
-- 
2.1.0