[4.2.y-ckt stable] Patch "net: check both type and procotol for tcp sockets" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    net: check both type and procotol for tcp sockets

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 81f36ecc45b6d1192b778dbf7fcc5d88762cee60 Mon Sep 17 00:00:00 2001
From: WANG Cong <xiyou.wangcong at gmail.com>
Date: Wed, 16 Dec 2015 23:39:04 -0800
Subject: net: check both type and procotol for tcp sockets

[ 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 at google.com>
Cc: Willem de Bruijn <willemdebruijn.kernel at gmail.com>
Cc: Eric Dumazet <eric.dumazet at gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong at gmail.com>
Acked-by: Willem de Bruijn <willemb at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/core/skbuff.c | 3 ++-
 net/core/sock.c   | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9ad9576..dd6d553 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3643,7 +3643,8 @@ static void __skb_complete_tx_timestamp(struct sk_buff *skb,
 	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;
 	}

diff --git a/net/core/sock.c b/net/core/sock.c
index 544ff7d..623224a 100644
--- 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;
--
1.9.1