Thread (5 messages) 5 messages, 4 authors, 2016-09-06

ipv6: release dst in ping_v6_sendmsg

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From: Dave Jones <hidden>
Date: 2016-09-02 18:39:54
Subsystem: networking [general], the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

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 <redacted>
Signed-off-by: Dave Jones <redacted>
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index 0900352c924c..0e983b694ee8 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -126,8 +126,10 @@ 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;
@@ -163,6 +165,9 @@ 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;
 
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