tree d9d6b96516cb03177c1bf00ce27a54785c74b50c
parent 265b88364426092cd21923dca8adff6a2176bf03
author Kees Cook <keescook@chromium.org> 1480962878 -0800
committer chrome-bot <chrome-bot@chromium.org> 1484795936 -0800

BACKPORT: net: ping: check minimum size on ICMP header length

Prior to commit c0371da6047a ("put iov_iter into msghdr") in v3.19, there
was no check that the iovec contained enough bytes for an ICMP header,
and the read loop would walk across neighboring stack contents. Since the
iov_iter conversion, bad arguments are noticed, but the returned error is
EFAULT. Returning EINVAL is a clearer error and also solves the problem
prior to v3.19.

This was found using trinity with KASAN on v3.18:

BUG: KASAN: stack-out-of-bounds in memcpy_fromiovec+0x60/0x114 at addr ffffffc071077da0
Read of size 8 by task trinity-c2/9623
page:ffffffbe034b9a08 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x0()
page dumped because: kasan: bad access detected
CPU: 0 PID: 9623 Comm: trinity-c2 Tainted: G    BU         3.18.0-dirty #15
Hardware name: Google Tegra210 Smaug Rev 1,3+ (DT)
Call trace:
[<ffffffc000209c98>] dump_backtrace+0x0/0x1ac arch/arm64/kernel/traps.c:90
[<ffffffc000209e54>] show_stack+0x10/0x1c arch/arm64/kernel/traps.c:171
[<     inline     >] __dump_stack lib/dump_stack.c:15
[<ffffffc000f18dc4>] dump_stack+0x7c/0xd0 lib/dump_stack.c:50
[<     inline     >] print_address_description mm/kasan/report.c:147
[<     inline     >] kasan_report_error mm/kasan/report.c:236
[<ffffffc000373dcc>] kasan_report+0x380/0x4b8 mm/kasan/report.c:259
[<     inline     >] check_memory_region mm/kasan/kasan.c:264
[<ffffffc00037352c>] __asan_load8+0x20/0x70 mm/kasan/kasan.c:507
[<ffffffc0005b9624>] memcpy_fromiovec+0x5c/0x114 lib/iovec.c:15
[<     inline     >] memcpy_from_msg include/linux/skbuff.h:2667
[<ffffffc000ddeba0>] ping_common_sendmsg+0x50/0x108 net/ipv4/ping.c:674
[<ffffffc000dded30>] ping_v4_sendmsg+0xd8/0x698 net/ipv4/ping.c:714
[<ffffffc000dc91dc>] inet_sendmsg+0xe0/0x12c net/ipv4/af_inet.c:749
[<     inline     >] __sock_sendmsg_nosec net/socket.c:624
[<     inline     >] __sock_sendmsg net/socket.c:632
[<ffffffc000cab61c>] sock_sendmsg+0x124/0x164 net/socket.c:643
[<     inline     >] SYSC_sendto net/socket.c:1797
[<ffffffc000cad270>] SyS_sendto+0x178/0x1d8 net/socket.c:1761

CVE-2016-8399

BUG=chromium:681957
TEST=Build and run

Change-Id: Ie0446d9dbafdf2c81e03c045e22caf727417533b
Reported-by: Qidan He <i@flanker017.me>
Fixes: c319b4d76b9e ("net: ipv4: add IPPROTO_ICMP socket kind")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
(cherry picked from commit 0eab121ef875)
[backport: icmp header length is fixed]
(cherry picked from commit 91ecac0cc4a9b97cb4cb5041818e0f9de68d9266)
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/428991
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>