general protection fault in selinux_socket

general protection fault in selinux_socket_recvmsg
Status: fixed on 2020/07/17 17:58
Reported-by: syzbot+c6bfc3db991edc918432@syzkaller.appspotmail.com
Fix commit: 0a82e230c688 mptcp: avoid NULL-ptr derefence on fallback
First crash: 440d, last: 439d

Cause bisection: introduced by (bisect log) :
commit 263e1201a2c324b60b15ecda5de9ebf1e7293e31
Author: Paolo Abeni <pabeni@redhat.com>
Date: Thu Apr 30 13:01:51 2020 +0000

mptcp: consolidate synack processing.

Crash: WARNING in warn_bad_map (log)
Repro: C syz .config

duplicates (1):
Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
general protection fault in sock_recvmsg	C	done		1	437d	437d	0/22	closed as dup on 2020/05/25 11:14

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2020/05/25 08:58	16m	pabeni@redhat.com	patch	net	OK

Sample crash report:

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 7370 Comm: syz-executor283 Not tainted 5.7.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:selinux_socket_recvmsg+0x1e/0x40 security/selinux/hooks.c:4841
Code: e8 77 f9 1e fe 48 89 ef 5d eb b1 90 53 48 89 fb e8 67 f9 1e fe 48 8d 7b 18 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 0f 48 8b 7b 18 be 02 00 00 00 5b e9 7d fc ff ff e8
RSP: 0018:ffffc900019d7a58 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000040000000
RDX: 0000000000000003 RSI: ffffffff83543bb9 RDI: 0000000000000018
RBP: dffffc0000000000 R08: ffff88809f45a180 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffc900019d7d78 R14: 0000000000001000 R15: 0000000040000000
FS:  00007f5ffb311700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ffb2efe78 CR3: 00000000a33c1000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 security_socket_recvmsg+0x78/0xc0 security/security.c:2070
 sock_recvmsg+0x47/0x110 net/socket.c:902
 mptcp_recvmsg+0xb3b/0xd90 net/mptcp/protocol.c:891
 inet_recvmsg+0x121/0x5d0 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_recvmsg+0xca/0x110 net/socket.c:900
 __sys_recvfrom+0x1c5/0x2f0 net/socket.c:2057
 __do_sys_recvfrom net/socket.c:2075 [inline]
 __se_sys_recvfrom net/socket.c:2071 [inline]
 __x64_sys_recvfrom+0xdd/0x1b0 net/socket.c:2071
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x448ef9
Code: e8 cc 14 03 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 0c fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5ffb310da8 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
RAX: ffffffffffffffda RBX: 00000000006dec28 RCX: 0000000000448ef9
RDX: 0000000000001000 RSI: 00000000200004c0 RDI: 0000000000000003
RBP: 00000000006dec20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000040000000 R11: 0000000000000246 R12: 00000000006dec2c
R13: 00007ffc3a001ccf R14: 00007f5ffb3119c0 R15: 00000000006dec2c
Modules linked in:
---[ end trace 60e1f3eb5a5b83ce ]---
RIP: 0010:selinux_socket_recvmsg+0x1e/0x40 security/selinux/hooks.c:4841
Code: e8 77 f9 1e fe 48 89 ef 5d eb b1 90 53 48 89 fb e8 67 f9 1e fe 48 8d 7b 18 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 0f 48 8b 7b 18 be 02 00 00 00 5b e9 7d fc ff ff e8
RSP: 0018:ffffc900019d7a58 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000040000000
RDX: 0000000000000003 RSI: ffffffff83543bb9 RDI: 0000000000000018
RBP: dffffc0000000000 R08: ffff88809f45a180 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffc900019d7d78 R14: 0000000000001000 R15: 0000000040000000
FS:  00007f5ffb311700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ffb2efe78 CR3: 00000000a33c1000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (4):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kasan-gce-selinux-root	2020/05/23 07:13	upstream	051143e1602d	9682898d	.config	log	report	syz	C
ci-upstream-kasan-gce-selinux-root	2020/05/23 06:46	upstream	051143e1602d	9682898d	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/05/22 15:08	upstream	d2f8825ab78e	5afa2ddd	.config	log	report
ci-qemu-upstream	2020/05/22 15:04	upstream	051143e1602d	9682898d	.config	log	report