general protection fault in aa_sock_msg_perm

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: c8dc5595 net/ibmvnic: Fix missing { in __ibmvnic_reset
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=1231cd6e600000
kernel config: https://syzkaller.appspot.com/x/.config?x=b89bb446a3faaba4
dashboard link: https://syzkaller.appspot.com/bug?extid=2f5c8bcfb1a85d2d5961
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [jmo...@namei.org john.j...@canonical.com
linux-...@vger.kernel.org linux-secu...@vger.kernel.org
se...@hallyn.com net...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2f5c8b...@syzkaller.appspotmail.com

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: krxrpcd rxrpc_peer_keepalive_worker
RIP: 0010:aa_sock_msg_perm.isra.0+0x41/0x170 security/apparmor/lsm.c:921
Code: 89 d3 e8 42 0f 68 fe 48 85 db 0f 84 9e 00 00 00 e8 34 0f 68 fe 4c 8d
7b 18 48 b8 00 00 00 00 00 fc ff df 4c 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 ff 00 00 00 48 83 7b 18 00 0f 84 8e 00 00 00 e8
RSP: 0018:ffff8880a98d79b0 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 00000000ffffffff RCX: ffff8880a98d7b20
RDX: 0000000020000002 RSI: ffffffff830a661c RDI: ffffffff87c082a0
RBP: ffff8880a98d79d8 R08: ffff8880a98c2300 R09: ffffed100df03512
R10: ffffed100df03511 R11: ffff88806f81a88b R12: ffff8880a98d7b20
R13: ffffffff87c082a0 R14: 0000000000000002 R15: 0000000100000017
FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000075c000 CR3: 00000000a92f6000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
apparmor_socket_sendmsg+0x2a/0x30 security/apparmor/lsm.c:936
security_socket_sendmsg+0x77/0xc0 security/security.c:1973
sock_sendmsg+0x45/0x130 net/socket.c:654
kernel_sendmsg+0x44/0x50 net/socket.c:677
rxrpc_send_keepalive+0x1ff/0x940 net/rxrpc/output.c:655
rxrpc_peer_keepalive_dispatch net/rxrpc/peer_event.c:369 [inline]
rxrpc_peer_keepalive_worker+0x7be/0xd02 net/rxrpc/peer_event.c:430
process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
worker_thread+0x98/0xe40 kernel/workqueue.c:2415
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace ba92ff8806604775 ]---
RIP: 0010:aa_sock_msg_perm.isra.0+0x41/0x170 security/apparmor/lsm.c:921
Code: 89 d3 e8 42 0f 68 fe 48 85 db 0f 84 9e 00 00 00 e8 34 0f 68 fe 4c 8d
7b 18 48 b8 00 00 00 00 00 fc ff df 4c 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 ff 00 00 00 48 83 7b 18 00 0f 84 8e 00 00 00 e8
RSP: 0018:ffff8880a98d79b0 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 00000000ffffffff RCX: ffff8880a98d7b20
RDX: 0000000020000002 RSI: ffffffff830a661c RDI: ffffffff87c082a0
RBP: ffff8880a98d79d8 R08: ffff8880a98c2300 R09: ffffed100df03512
R10: ffffed100df03511 R11: ffff88806f81a88b R12: ffff8880a98d7b20
R13: ffffffff87c082a0 R14: 0000000000000002 R15: 0000000100000017
FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001cd9fd0 CR3: 0000000091072000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

> net/rxrpc/output.c:655

> #syz dup: KASAN: use-after-free Read in rxrpc_send_keepalive

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