| Message ID | 1434576472-24803-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 01176f0..758a85d 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -917,6 +917,10 @@ static int ip_error(struct sk_buff *skb) bool send; int code; + /* IP on this device is disabled. */ + if (!in_dev) + goto out; + net = dev_net(rt->dst.dev); if (!IN_DEV_FORWARD(in_dev)) { switch (rt->dst.error) {
This is a note to let you know that I have just added a patch titled ipv4: Avoid crashing in ip_error to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11-ckt22. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 5fb1c73e10c615610115785877f0c422efc0f2df Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" <ebiederm@xmission.com> Date: Fri, 22 May 2015 04:58:12 -0500 Subject: ipv4: Avoid crashing in ip_error commit 381c759d9916c42959515ad34a6d467e24a88e93 upstream. ip_error does not check if in_dev is NULL before dereferencing it. IThe following sequence of calls is possible: CPU A CPU B ip_rcv_finish ip_route_input_noref() ip_route_input_slow() inetdev_destroy() dst_input() With the result that a network device can be destroyed while processing an input packet. A crash was triggered with only unicast packets in flight, and forwarding enabled on the only network device. The error condition was created by the removal of the network device. As such it is likely the that error code was -EHOSTUNREACH, and the action taken by ip_error (if in_dev had been accessible) would have been to not increment any counters and to have tried and likely failed to send an icmp error as the network device is going away. Therefore handle this weird case by just dropping the packet if !in_dev. It will result in dropping the packet sooner, and will not result in an actual change of behavior. Fixes: 251da4130115b ("ipv4: Cache ip_error() routes even when not forwarding.") Reported-by: Vittorio Gambaletta <linuxbugs@vittgam.net> Tested-by: Vittorio Gambaletta <linuxbugs@vittgam.net> Signed-off-by: Vittorio Gambaletta <linuxbugs@vittgam.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- net/ipv4/route.c | 4 ++++ 1 file changed, 4 insertions(+) -- 1.9.1