[PATCH 4.3 42/55] net: check both type and procotol for tcp sockets

From: Greg Kroah-Hartman
Date: Wed Jan 20 2016 - 19:51:27 EST


4.3-stable review patch. If anyone has any objections, please let me know.

------------------

From: WANG Cong <xiyou.wangcong@xxxxxxxxx>

[ Upstream commit ac5cc977991d2dce85fc734a6c71ddb33f6fe3c1 ]

Dmitry reported the following out-of-bound access:

Call Trace:
[<ffffffff816cec2e>] __asan_report_load4_noabort+0x3e/0x40
mm/kasan/report.c:294
[<ffffffff84affb14>] sock_setsockopt+0x1284/0x13d0 net/core/sock.c:880
[< inline >] SYSC_setsockopt net/socket.c:1746
[<ffffffff84aed7ee>] SyS_setsockopt+0x1fe/0x240 net/socket.c:1729
[<ffffffff85c18c76>] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185

This is because we mistake a raw socket as a tcp socket.
We should check both sk->sk_type and sk->sk_protocol to ensure
it is a tcp socket.

Willem points out __skb_complete_tx_timestamp() needs to fix as well.

Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx>
Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Acked-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/skbuff.c | 3 ++-
net/core/sock.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)

--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3643,7 +3643,8 @@ static void __skb_complete_tx_timestamp(
serr->ee.ee_info = tstype;
if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) {
serr->ee.ee_data = skb_shinfo(skb)->tskey;
- if (sk->sk_protocol == IPPROTO_TCP)
+ if (sk->sk_protocol == IPPROTO_TCP &&
+ sk->sk_type == SOCK_STREAM)
serr->ee.ee_data -= sk->sk_tskey;
}

--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -860,7 +860,8 @@ set_rcvbuf:

if (val & SOF_TIMESTAMPING_OPT_ID &&
!(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)) {
- if (sk->sk_protocol == IPPROTO_TCP) {
+ if (sk->sk_protocol == IPPROTO_TCP &&
+ sk->sk_type == SOCK_STREAM) {
if (sk->sk_state != TCP_ESTABLISHED) {
ret = -EINVAL;
break;