Patch "kcm: fix a null pointer dereference in kcm_sendmsg()" has been added to the 4.9-stable tree

Patch "kcm: fix a null pointer dereference in kcm_sendmsg()" 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

    kcm: fix a null pointer dereference in kcm_sendmsg()

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:
     kcm-fix-a-null-pointer-dereference-in-kcm_sendmsg.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 Feb 23 21:13:05 CET 2017
From: WANG Cong <xiyou.wangcong@gmail.com>
Date: Mon, 13 Feb 2017 11:13:16 -0800
Subject: kcm: fix a null pointer dereference in kcm_sendmsg()

From: WANG Cong <xiyou.wangcong@gmail.com>


[ Upstream commit cd27b96bc13841ee7af25837a6ae86fee87273d6 ]

In commit 98e3862ca2b1 ("kcm: fix 0-length case for kcm_sendmsg()")
I tried to avoid skb allocation for 0-length case, but missed
a check for NULL pointer in the non EOR case.

Fixes: 98e3862ca2b1 ("kcm: fix 0-length case for kcm_sendmsg()")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/kcm/kcmsock.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1044,8 +1044,10 @@ wait_for_memory:
 	} else {
 		/* Message not complete, save state */
 partial_message:
-		kcm->seq_skb = head;
-		kcm_tx_msg(head)->last_skb = skb;
+		if (head) {
+			kcm->seq_skb = head;
+			kcm_tx_msg(head)->last_skb = skb;
+		}
 	}
 
 	KCM_STATS_ADD(kcm->stats.tx_bytes, copied);


Patches currently in stable-queue which might be from xiyou.wangcong@gmail.com are

queue-4.9/kcm-fix-0-length-case-for-kcm_sendmsg.patch
queue-4.9/kcm-fix-a-null-pointer-dereference-in-kcm_sendmsg.patch