From 346da62cc186c4b4b1ac59f87f4482b47a047388 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 2 Nov 2016 18:04:24 -0700 Subject: [PATCH] dccp: do not send reset to already closed sockets 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 [] dump_stack+0xb3/0x10f lib/dump_stack.c:51 [] panic+0x1bc/0x39d kernel/panic.c:179 [] __warn+0x1cc/0x1f0 kernel/panic.c:542 [] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585 [] dccp_set_state+0x229/0x290 net/dccp/proto.c:83 [] dccp_close+0x612/0xc10 net/dccp/proto.c:1016 [] inet_release+0xef/0x1c0 net/ipv4/af_inet.c:415 [] sock_release+0x8e/0x1d0 net/socket.c:570 [] sock_close+0x16/0x20 net/socket.c:1017 [] __fput+0x29d/0x720 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0xf8/0x170 kernel/task_work.c:116 [< inline >] exit_task_work include/linux/task_work.h:21 [] do_exit+0x883/0x2ac0 kernel/exit.c:828 [] do_group_exit+0x10e/0x340 kernel/exit.c:931 [] get_signal+0x634/0x15a0 kernel/signal.c:2307 [] do_signal+0x8d/0x1a30 arch/x86/kernel/signal.c:807 [] exit_to_usermode_loop+0xe5/0x130 arch/x86/entry/common.c:156 [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:190 [] syscall_return_slowpath+0x1a8/0x1e0 arch/x86/entry/common.c:259 [] 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 Reported-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: David S. Miller --- net/dccp/proto.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/dccp/proto.c b/net/dccp/proto.c index 41e65804ddf5..9fe25bf63296 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -1009,6 +1009,10 @@ 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); -- 2.20.1