general protection fault in j1939_sk_sendmsg

general protection fault in j1939_sk_sendmsg

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    3d1e5039 dccp: do not leak jiffies on the wire
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=1667443ae00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cbbed3e8d4eb64bf
dashboard link: https://syzkaller.appspot.com/bug?extid=7044ea77452b6f92b4fd
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1063f1c8e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+7044ea77452b6f92b4fd@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 9129 Comm: syz-executor.0 Not tainted 5.4.0-rc5+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:j1939_sk_send_loop net/can/j1939/socket.c:983 [inline]
RIP: 0010:j1939_sk_sendmsg+0x6d6/0x1450 net/can/j1939/socket.c:1100
Code: e8 9f 16 f4 fa 48 8b 8d 50 ff ff ff b8 f9 06 00 00 48 81 f9 f9 06 00  
00 48 0f 46 c1 48 89 85 60 ff ff ff 48 8b 85 20 ff ff ff <80> 38 00 0f 85  
fa 0a 00 00 48 8b 85 40 ff ff ff 48 8b 58 48 48 8b
RSP: 0018:ffff88808189fa28 EFLAGS: 00010206
RAX: dffffc0000000009 RBX: 0000000006fffff9 RCX: 0000000006fffff9
RDX: 0000000000000000 RSI: ffffffff867f0c31 RDI: 0000000000000007
RBP: ffff88808189fb40 R08: ffff888091482400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff88809195b510 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fb51830c700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb51832cdb8 CR3: 00000000a845c000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  sock_sendmsg_nosec net/socket.c:637 [inline]
  sock_sendmsg+0xd7/0x130 net/socket.c:657
  ___sys_sendmsg+0x803/0x920 net/socket.c:2311
  __sys_sendmsg+0x105/0x1d0 net/socket.c:2356
  __do_sys_sendmsg net/socket.c:2365 [inline]
  __se_sys_sendmsg net/socket.c:2363 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a219
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb51830bc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a219
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 000000000075c118 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb51830c6d4
R13: 00000000004c804e R14: 00000000004de4d0 R15: 00000000ffffffff
Modules linked in:
---[ end trace b093e29acd07b362 ]---
RIP: 0010:j1939_sk_send_loop net/can/j1939/socket.c:983 [inline]
RIP: 0010:j1939_sk_sendmsg+0x6d6/0x1450 net/can/j1939/socket.c:1100
Code: e8 9f 16 f4 fa 48 8b 8d 50 ff ff ff b8 f9 06 00 00 48 81 f9 f9 06 00  
00 48 0f 46 c1 48 89 85 60 ff ff ff 48 8b 85 20 ff ff ff <80> 38 00 0f 85  
fa 0a 00 00 48 8b 85 40 ff ff ff 48 8b 58 48 48 8b
RSP: 0018:ffff88808189fa28 EFLAGS: 00010206
RAX: dffffc0000000009 RBX: 0000000006fffff9 RCX: 0000000006fffff9
RDX: 0000000000000000 RSI: ffffffff867f0c31 RDI: 0000000000000007
RBP: ffff88808189fb40 R08: ffff888091482400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff88809195b510 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fb51830c700(000


---
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Re: general protection fault in j1939_sk_sendmsg

[syzbot]

syzbot has bisected this bug to:

commit 9d71dd0c70099914fcd063135da3c580865e924c
Author: The j1939 authors <linux-can@vger.kernel.org>
Date:   Mon Oct 8 09:48:36 2018 +0000

     can: add support of SAE J1939 protocol

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15874852e00000
start commit:   a99d8080 Linux 5.4-rc6
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=17874852e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=13874852e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8c5e2eca3f31f9bf
dashboard link: https://syzkaller.appspot.com/bug?extid=7044ea77452b6f92b4fd
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15a99e8ae00000

Reported-by: syzbot+7044ea77452b6f92b4fd@syzkaller.appspotmail.com
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection