Subject: [syzbot] [crypto?] general protection fault in shash_async_final

From: syzbot <[email-masked]>
Date: Mon, 12 Jun 2023 02:41:59 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    37ff78e977f1 mlxsw: spectrum_nve_vxlan: Fix unsupported fl..
git tree:       net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13b26ef1280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=526f919910d4a671
dashboard link: https://syzkaller.appspot.com/bug?extid=13a08c0bf4d212766c3c
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=165dc395280000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13f9172b280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/41e829152d3c/disk-37ff78e9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a594b97acb02/vmlinux-37ff78e9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b41140b53372/bzImage-37ff78e9.xz

The issue was bisected to:

commit c662b043cdca89bf0f03fc37251000ac69a3a548
Author: David Howells <[email-masked]>
Date:   Tue Jun 6 13:08:56 2023 +0000

    crypto: af_alg/hash: Support MSG_SPLICE_PAGES

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14a2def1280000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=16a2def1280000
console output: https://syzkaller.appspot.com/x/log.txt?x=12a2def1280000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: c662b043cdca ("crypto: af_alg/hash: Support MSG_SPLICE_PAGES")

general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 PID: 5003 Comm: syz-executor289 Not tainted 6.4.0-rc5-syzkaller-00859-g37ff78e977f1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:crypto_shash_alg include/crypto/hash.h:827 [inline]
RIP: 0010:crypto_shash_final crypto/shash.c:171 [inline]
RIP: 0010:shash_async_final+0x6d/0x150 crypto/shash.c:319
Code: 4c 89 e2 48 c1 ea 03 80 3c 02 00 0f 85 d5 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 50 48 8d 7b 20 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc900039af8f8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff83df3032 RDI: 0000000000000020
RBP: 0000000000000010 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000655 R12: ffff88801f6c0af8
R13: 0000000000000010 R14: ffff888015fd1000 R15: ffff88801f6c0a38
FS:  00005555561eb300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000107b3a8 CR3: 0000000078da9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 crypto_ahash_op crypto/ahash.c:303 [inline]
 crypto_ahash_op crypto/ahash.c:292 [inline]
 crypto_ahash_final+0xed/0x1e0 crypto/ahash.c:316
 hash_recvmsg+0x2c6/0xa80 crypto/algif_hash.c:248
 hash_recvmsg_nokey+0x69/0x90 crypto/algif_hash.c:404
 sock_recvmsg_nosec net/socket.c:1019 [inline]
 sock_recvmsg+0xe2/0x160 net/socket.c:1040
 ____sys_recvmsg+0x210/0x5a0 net/socket.c:2724
 ___sys_recvmsg+0xf2/0x180 net/socket.c:2766
 do_recvmmsg+0x25e/0x6f0 net/socket.c:2860
 __sys_recvmmsg net/socket.c:2939 [inline]
 __do_sys_recvmmsg net/socket.c:2962 [inline]
 __se_sys_recvmmsg net/socket.c:2955 [inline]
 __x64_sys_recvmmsg+0x20f/0x260 net/socket.c:2955
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f030b570c49
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd507d5968 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f030b570c49
RDX: 000000000000049f RSI: 0000000020006100 RDI: 0000000000000004
RBP: 00007f030b534df0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f030b534e80
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:crypto_shash_alg include/crypto/hash.h:827 [inline]
RIP: 0010:crypto_shash_final crypto/shash.c:171 [inline]
RIP: 0010:shash_async_final+0x6d/0x150 crypto/shash.c:319
Code: 4c 89 e2 48 c1 ea 03 80 3c 02 00 0f 85 d5 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 50 48 8d 7b 20 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc900039af8f8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff83df3032 RDI: 0000000000000020
RBP: 0000000000000010 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000655 R12: ffff88801f6c0af8
R13: 0000000000000010 R14: ffff888015fd1000 R15: ffff88801f6c0a38
FS:  00005555561eb300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000107b3a8 CR3: 0000000078da9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	4c 89 e2             	mov    %r12,%rdx
   3:	48 c1 ea 03          	shr    $0x3,%rdx
   7:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   b:	0f 85 d5 00 00 00    	jne    0xe6
  11:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  18:	fc ff df
  1b:	48 8b 5b 50          	mov    0x50(%rbx),%rbx
  1f:	48 8d 7b 20          	lea    0x20(%rbx),%rdi
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 a8 00 00 00    	jne    0xdc
  34:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  3b:	fc ff df
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b

---
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