Patch "sctp: fix dst refcnt leak in sctp_v6_get_dst()" has been added to the 4.9-stable tree

Patch "sctp: fix dst refcnt leak in sctp_v6_get_dst()" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    sctp: fix dst refcnt leak in sctp_v6_get_dst()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sctp-fix-dst-refcnt-leak-in-sctp_v6_get_dst.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Mar  8 06:55:02 PST 2018
From: Alexey Kodanev <alexey.kodanev@oracle.com>
Date: Mon, 5 Feb 2018 15:10:35 +0300
Subject: sctp: fix dst refcnt leak in sctp_v6_get_dst()

From: Alexey Kodanev <alexey.kodanev@oracle.com>


[ Upstream commit 957d761cf91cdbb175ad7d8f5472336a4d54dbf2 ]

When going through the bind address list in sctp_v6_get_dst() and
the previously found address is better ('matchlen > bmatchlen'),
the code continues to the next iteration without releasing currently
held destination.

Fix it by releasing 'bdst' before continue to the next iteration, and
instead of introducing one more '!IS_ERR(bdst)' check for dst_release(),
move the already existed one right after ip6_dst_lookup_flow(), i.e. we
shouldn't proceed further if we get an error for the route lookup.

Fixes: dbc2b5e9a09e ("sctp: fix src address selection if using secondary addresses for ipv6")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/ipv6.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -324,8 +324,10 @@ static void sctp_v6_get_dst(struct sctp_
 		final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
 		bdst = ip6_dst_lookup_flow(sk, fl6, final_p);
 
-		if (!IS_ERR(bdst) &&
-		    ipv6_chk_addr(dev_net(bdst->dev),
+		if (IS_ERR(bdst))
+			continue;
+
+		if (ipv6_chk_addr(dev_net(bdst->dev),
 				  &laddr->a.v6.sin6_addr, bdst->dev, 1)) {
 			if (!IS_ERR_OR_NULL(dst))
 				dst_release(dst);
@@ -334,8 +336,10 @@ static void sctp_v6_get_dst(struct sctp_
 		}
 
 		bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
-		if (matchlen > bmatchlen)
+		if (matchlen > bmatchlen) {
+			dst_release(bdst);
 			continue;
+		}
 
 		if (!IS_ERR_OR_NULL(dst))
 			dst_release(dst);


Patches currently in stable-queue which might be from alexey.kodanev@oracle.com are

queue-4.9/sctp-fix-dst-refcnt-leak-in-sctp_v6_get_dst.patch
queue-4.9/udplite-fix-partial-checksum-initialization.patch
queue-4.9/sctp-verify-size-of-a-new-chunk-in-_sctp_make_chunk.patch