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 4.4-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: ipv4-provide-stronger-user-input-validation-in-nl_fib_input.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@xxxxxxxxxxxxxxx> know about it. >From foo@baz Mon Mar 27 18:22:09 CEST 2017 From: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Tue, 21 Mar 2017 19:22:28 -0700 Subject: ipv4: provide stronger user input validation in nl_fib_input() From: Eric Dumazet <edumazet@xxxxxxxxxx> [ 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. Reported-by: Alexander Potapenko <glider@xxxxxxxxxx> Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/fib_frontend.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -1080,7 +1080,8 @@ 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 edumazet@xxxxxxxxxx are queue-4.4/ipv4-provide-stronger-user-input-validation-in-nl_fib_input.patch queue-4.4/tcp-initialize-icsk_ack.lrcvtime-at-session-start-time.patch queue-4.4/net-properly-release-sk_frag.page.patch