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authorSiqi Lin <siqilin@google.com>2016-10-13 16:27:46 -0700
committerSimon Shields <keepcalm444@gmail.com>2016-12-13 00:14:53 +1100
commitd7764316afed610cd1ce62a6f01ae465367bbf0a (patch)
tree14be028ad6a4e02a2667d7e92a643254454e6968
parent12bf2ab391d33a49d74b123b66ef87c4ffa14e2e (diff)
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net: ping: Fix stack buffer overflow in ping_common_sendmsg()
In ping_common_sendmsg(), when len < icmph_len, memcpy_fromiovec() will access invalid memory because msg->msg_iov only has 1 element and memcpy_fromiovec() attempts to increment it. KASAN report: 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 Memory state around the buggy address: ffffffc071077c80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 f1 f1 ffffffc071077d00: f1 f1 04 f4 f4 f4 f2 f2 f2 f2 04 f4 f4 f4 f2 f2 >ffffffc071077d80: f2 f2 00 00 f4 f4 f2 f2 f2 f2 00 00 00 00 00 00 ^ ffffffc071077e00: 00 f4 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 ffffffc071077e80: 00 00 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 RM-290 Bug: 31349935 Change-Id: Ib7385fc26dfe7e07e9bab42a10ff65a37cbaab54 Signed-off-by: Siqi Lin <siqilin@google.com>
-rw-r--r--net/ipv4/ping.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 93fbd72..02743c2 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -641,7 +641,7 @@ int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
void *user_icmph, size_t icmph_len) {
u8 type, code;
- if (len > 0xFFFF)
+ if (len > 0xFFFF || len < icmph_len)
return -EMSGSIZE;
/*