Subject: Re: general protection fault in tls_trim_both_msgs

From: syzbot <[email-masked]>
Date: Sat, 27 Jul 2019 04:40:05 -0700

syzbot has found a reproducer for the following crash on:

HEAD commit:    fde50b96 Add linux-next specific files for 20190726
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=142826cc600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4b58274564b354c1
dashboard link: https://syzkaller.appspot.com/bug?extid=0e0fedcad708d12d3032
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14779d64600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1587c842600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

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: 10205 Comm: syz-executor265 Not tainted 5.3.0-rc1-next-20190726  
#53
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:tls_trim_both_msgs+0x54/0x130 net/tls/tls_sw.c:268
Code: 48 c1 ea 03 80 3c 02 00 0f 85 e3 00 00 00 4d 8b b5 b0 06 00 00 48 b8  
00 00 00 00 00 fc ff df 49 8d 7e 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f  
85 b3 00 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff88809037fac0 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8880a8c0eec0 RCX: ffffffff862f4eef
RDX: 0000000000000005 RSI: ffffffff862e9016 RDI: 0000000000000028
RBP: ffff88809037fae0 R08: ffff8880944a8040 R09: ffffed10125e7d51
R10: ffffed10125e7d50 R11: ffff888092f3ea83 R12: 0000000000000000
R13: ffff8880a9560c80 R14: 0000000000000000 R15: 00000000ffffffe0
FS:  000055555717a880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc5f44109c0 CR3: 000000008b1cc000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  tls_sw_sendmsg+0xe38/0x17b0 net/tls/tls_sw.c:1057
  inet6_sendmsg+0x9e/0xe0 net/ipv6/af_inet6.c:576
  sock_sendmsg_nosec net/socket.c:637 [inline]
  sock_sendmsg+0xd7/0x130 net/socket.c:657
  __sys_sendto+0x262/0x380 net/socket.c:1952
  __do_sys_sendto net/socket.c:1964 [inline]
  __se_sys_sendto net/socket.c:1960 [inline]
  __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1960
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441339
Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 9b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffef90e4908 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441339
RDX: ffffffffffffffc1 RSI: 00000000200005c0 RDI: 0000000000000003
RBP: 00000000006cb018 R08: 0000000000000000 R09: 1201000000003618
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402160
R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 94e33101f438b014 ]---
RIP: 0010:tls_trim_both_msgs+0x54/0x130 net/tls/tls_sw.c:268
Code: 48 c1 ea 03 80 3c 02 00 0f 85 e3 00 00 00 4d 8b b5 b0 06 00 00 48 b8  
00 00 00 00 00 fc ff df 49 8d 7e 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f  
85 b3 00 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffff88809037fac0 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8880a8c0eec0 RCX: ffffffff862f4eef
RDX: 0000000000000005 RSI: ffffffff862e9016 RDI: 0000000000000028
RBP: ffff88809037fae0 R08: ffff8880944a8040 R09: ffffed10125e7d51
R10: ffffed10125e7d50 R11: ffff888092f3ea83 R12: 0000000000000000
R13: ffff8880a9560c80 R14: 0000000000000000 R15: 00000000ffffffe0
FS:  000055555717a880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc5f44109c0 CR3: 000000008b1cc000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400