[PATCH 3.10 261/319] dccp: do not send reset to already closed sockets

Willy Tarreau
2017-02-05T19:26:05Z

From: Eric Dumazet <edumazet@google.com>

commit 346da62cc186c4b4b1ac59f87f4482b47a047388 upstream.

Andrey reported following warning while fuzzing with syzkaller

WARNING: CPU: 1 PID: 21072 at net/dccp/proto.c:83 dccp_set_state+0x229/0x290
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 21072 Comm: syz-executor Not tainted 4.9.0-rc1+ #293
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
ffff88003d4c7738 ffffffff81b474f4 0000000000000003 dffffc0000000000
ffffffff844f8b00 ffff88003d4c7804 ffff88003d4c7800 ffffffff8140c06a
0000000041b58ab3 ffffffff8479ab7d ffffffff8140beae ffffffff8140cd00
Call Trace:
[< inline >] __dump_stack lib/dump_stack.c:15
[<ffffffff81b474f4>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
[<ffffffff8140c06a>] panic+0x1bc/0x39d kernel/panic.c:179
[<ffffffff8111125c>] __warn+0x1cc/0x1f0 kernel/panic.c:542
[<ffffffff8111144c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
[<ffffffff8389e5d9>] dccp_set_state+0x229/0x290 net/dccp/proto.c:83
[<ffffffff838a0aa2>] dccp_close+0x612/0xc10 net/dccp/proto.c:1016
[<ffffffff8316bf1f>] inet_release+0xef/0x1c0 net/ipv4/af_inet.c:415
[<ffffffff82b6e89e>] sock_release+0x8e/0x1d0 net/socket.c:570
[<ffffffff82b6e9f6>] sock_close+0x16/0x20 net/socket.c:1017
[<ffffffff815256ad>] __fput+0x29d/0x720 fs/file_table.c:208
[<ffffffff81525bb5>] ____fput+0x15/0x20 fs/file_table.c:244
[<ffffffff811727d8>] task_work_run+0xf8/0x170 kernel/task_work.c:116
[< inline >] exit_task_work include/linux/task_work.h:21
[<ffffffff8111bc53>] do_exit+0x883/0x2ac0 kernel/exit.c:828
[<ffffffff811221fe>] do_group_exit+0x10e/0x340 kernel/exit.c:931
[<ffffffff81143c94>] get_signal+0x634/0x15a0 kernel/signal.c:2307
[<ffffffff81054aad>] do_signal+0x8d/0x1a30 arch/x86/kernel/signal.c:807
[<ffffffff81003a05>] exit_to_usermode_loop+0xe5/0x130
arch/x86/entry/common.c:156
[< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:190
[<ffffffff81006298>] syscall_return_slowpath+0x1a8/0x1e0
arch/x86/entry/common.c:259
[<ffffffff83fc1a62>] entry_SYSCALL_64_fastpath+0xc0/0xc2
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled

Fix this the same way we did for TCP in commit 565b7b2d2e63
("tcp: do not send reset to already closed sockets")

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
net/dccp/proto.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 6c7c78b8..cb55fb9 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -1012,6 +1012,10 @@ void dccp_close(struct sock *sk, long timeout)
__kfree_skb(skb);
}

+ /* If socket has been already reset kill it. */
+ if (sk->sk_state == DCCP_CLOSED)
+ goto adjudge_to_death;
+
if (data_was_unread) {
/* Unread data was tossed, send an appropriate Reset Code */
DCCP_WARN("ABORT with %u bytes unread\n", data_was_unread);
--
2.8.0.rc2.1.gbe9624a