FROMGIT: tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()

commit 967c05aee439e6e5d7d805e195b3a20ef5c433d6 upstream.

If mtu probing is enabled tcp_mtu_probing() could very well end up
with a too small MSS.

Use the new sysctl tcp_min_snd_mss to make sure MSS search
is performed in an acceptable range.

CVE-2019-11479 -- tcp mss hardcoded to 48

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: Jonathan Looney <jtl@netflix.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Bruce Curtis <brucec@netflix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 59222807fcc99951dc769cd50e132e319d73d699
 git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git linux-4.19.y)
Signed-off-by: Robert Kolchmeyer <rkolchmeyer@google.com>

BUG=b:135494242
TEST=build and run

Change-Id: I6c04a5c64dc3e79733c646cb47d736a3a19af95c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1670618
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Tested-by: Robert Kolchmeyer <rkolchmeyer@google.com>
1 file changed