general protection fault in dccp_write

general protection fault in dccp_write_xmit
Status: fixed on 2018/03/23 18:14
Reported-by: syzbot+f99ab3887ab65d70f816@syzkaller.appspotmail.com
Fix commit: 67f93df7 dccp: check sk for closed state in dccp_sendmsg()
First crash: 1004d, last: 959d

Sample crash report:

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4830 Comm: syzkaller256346 Not tainted 4.16.0-rc4+ #342
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ccid_hc_tx_send_packet net/dccp/ccid.h:169 [inline]
RIP: 0010:dccp_write_xmit+0x69/0x1d0 net/dccp/output.c:353
RSP: 0018:ffff8801d90ef708 EFLAGS: 00010246
RAX: ffff8801d85fa400 RBX: ffff8801d1b86040 RCX: ffffffff854d7bd1
RDX: 0000000000000000 RSI: 1ffff1003b0bf593 RDI: ffff8801d1b86040
RBP: ffff8801d90ef738 R08: 1ffff1003b21dea3 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801daf4c0c0
R13: dffffc0000000000 R14: ffffed003a370d03 R15: 0000000000000000
FS:  00007f3d6c238700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002047b000 CR3: 00000001b0f13006 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 dccp_sendmsg+0x95f/0xdc0 net/dccp/proto.c:813
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046
 __sys_sendmsg+0xe5/0x210 net/socket.c:2080
 SYSC_sendmsg net/socket.c:2091 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2087
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x446c19
RSP: 002b:00007f3d6c237db8 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006e29e4 RCX: 0000000000446c19
RDX: 0000000020000000 RSI: 0000000020000140 RDI: 0000000000000006
RBP: 00000000006e29e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fff4243261f R14: 00007f3d6c2389c0 R15: 0000000000000009
Code: 00 00 48 85 c0 49 89 c4 0f 84 fb 00 00 00 e8 5f 8a 23 fc 41 80 3e 00 0f 85 5a 01 00 00 4c 8b bb d8 07 00 00 4c 89 fa 48 c1 ea 03 <42> 80 3c 2a 00 0f 85 34 01 00 00 4d 8b 3f 49 8d bf b0 00 00 00 
RIP: ccid_hc_tx_send_packet net/dccp/ccid.h:169 [inline] RSP: ffff8801d90ef708
RIP: dccp_write_xmit+0x69/0x1d0 net/dccp/output.c:353 RSP: ffff8801d90ef708
---[ end trace 208b13b56f4da922 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (5):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce	2018/03/06 10:09	upstream	094b58e1	aef0b792	.config	log	report	syz	C	davem@davemloft.net, dccp@vger.kernel.org, gerrit@erg.abdn.ac.uk, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-net-kasan-gce	2018/03/06 10:10	net-next	ef3f6c25	aef0b792	.config	log	report	syz	C	davem@davemloft.net, dccp@vger.kernel.org, gerrit@erg.abdn.ac.uk, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-kasan-gce-386	2018/03/06 10:08	upstream	094b58e1	aef0b792	.config	log	report	syz		davem@davemloft.net, dccp@vger.kernel.org, gerrit@erg.abdn.ac.uk, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-net-kasan-gce	2018/01/28 21:53	net-next	751c45bd	08d47756	.config	log	report	syz		davem@davemloft.net, dccp@vger.kernel.org, gerrit@erg.abdn.ac.uk, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-net-kasan-gce	2018/01/19 21:35	net-next	43dd7512	fbbdcd92	.config	log	report			davem@davemloft.net, dccp@vger.kernel.org, gerrit@erg.abdn.ac.uk, linux-kernel@vger.kernel.org, netdev@vger.kernel.org