Patch "sctp: check af before verify address in sctp_addr_id2transport" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    sctp: check af before verify address in sctp_addr_id2transport

to the 4.4-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-check-af-before-verify-address-in-sctp_addr_id2transport.patch
and it can be found in the queue-4.4 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 Mon Jul  3 13:41:44 CEST 2017
From: Xin Long <lucien.xin@gmail.com>
Date: Tue, 7 Feb 2017 20:56:08 +0800
Subject: sctp: check af before verify address in sctp_addr_id2transport

From: Xin Long <lucien.xin@gmail.com>


[ Upstream commit 912964eacb111551db73429719eb5fadcab0ff8a ]

Commit 6f29a1306131 ("sctp: sctp_addr_id2transport should verify the
addr before looking up assoc") invoked sctp_verify_addr to verify the
addr.

But it didn't check af variable beforehand, once users pass an address
with family = 0 through sockopt, sctp_get_af_specific will return NULL
and NULL pointer dereference will be caused by af->sockaddr_len.

This patch is to fix it by returning NULL if af variable is NULL.

Fixes: 6f29a1306131 ("sctp: sctp_addr_id2transport should verify the addr before looking up assoc")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/socket.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -239,7 +239,7 @@ static struct sctp_transport *sctp_addr_
 	union sctp_addr *laddr = (union sctp_addr *)addr;
 	struct sctp_transport *transport;
 
-	if (sctp_verify_addr(sk, laddr, af->sockaddr_len))
+	if (!af || sctp_verify_addr(sk, laddr, af->sockaddr_len))
 		return NULL;
 
 	addr_asoc = sctp_endpoint_lookup_assoc(sctp_sk(sk)->ep,


Patches currently in stable-queue which might be from lucien.xin@gmail.com are

queue-4.4/ipv6-fix-calling-in6_ifa_hold-incorrectly-for-dad-work.patch
queue-4.4/igmp-acquire-pmc-lock-for-ip_mc_clear_src.patch
queue-4.4/sctp-check-af-before-verify-address-in-sctp_addr_id2transport.patch