Patch "ipv4: provide stronger user input validation in nl_fib_input()" has been added to the 4.10-stable tree

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

ipv4: provide stronger user input validation in nl_fib_input()

to the 4.10-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:
ipv4-provide-stronger-user-input-validation-in-nl_fib_input.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Eric Dumazet <[email protected]>
Date: Tue, 21 Mar 2017 19:22:28 -0700
Subject: ipv4: provide stronger user input validation in nl_fib_input()

From: Eric Dumazet <[email protected]>

[ Upstream commit c64c0b3cac4c5b8cb093727d2c19743ea3965c0b ]

Alexander reported a KMSAN splat caused by reads of uninitialized field (tb_id_in) from user provided struct fib_result_nl

It turns out nl_fib_input() sanity tests on user input is a bit wrong :

User can pretend nlh->nlmsg_len is big enough, but provide at sendmsg() time a too small buffer.

---
 net/ipv4/fib_frontend.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -1082,7 +1082,8 @@ static void nl_fib_input(struct sk_buff
 
 	net = sock_net(skb->sk);
 	nlh = nlmsg_hdr(skb);
-	if (skb->len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len ||
+	if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
+	    skb->len < nlh->nlmsg_len ||
 	    nlmsg_len(nlh) < sizeof(*frn))
 		return;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/ipv4-provide-stronger-user-input-validation-in-nl_fib_input.patch queue-4.10/net-solve-a-napi-race.patch queue-4.10/tcp-initialize-icsk_ack.lrcvtime-at-session-start-time.patch queue-4.10/net-properly-release-sk_frag.page.patch