[syzbot] [dm?] general protection fault in crypt_setkey

[syzbot] [dm?] general protection fault in crypt_setkey

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    6b4b543fa187 Merge tag 'parisc-for-7.4-rc1' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15f0008d580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e0dd24ec63572ca
dashboard link: https://syzkaller.appspot.com/bug?extid=ff132cb52bce4f44ecc9
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=138a6f0d580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1583c259580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-6b4b543f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8a7c3186fb53/vmlinux-6b4b543f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/54ff5a2a5728/bzImage-6b4b543f.xz

AI-generated root cause summary:
In drivers/md/dm-crypt.c, specifying the optional "integrity_key_size" parameter
alongside an AEAD integrity profile sets cc->key_mac_size, causing
crypt_integrity_hmac() to evaluate to true. However, when the specified cipher
is not an authenc composite algorithm (e.g., rfc7539(chacha20,poly1305)),
crypt_ctr_auth_cipher() exits early without allocating cc->authenc_key. During
key initialization, crypt_setkey() calls crypt_copy_authenckey() with the NULL
cc->authenc_key pointer, leading to a kernel NULL-pointer dereference crash
(denial of service).

full analysis:  https://syzkaller.appspot.com/x/ai_root_cause?x=ff132cb52bce4f44ecc9

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ff132cb52bce4f44ecc9@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 5579 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:crypt_copy_authenckey drivers/md/dm-crypt.c:2396 [inline]
RIP: 0010:crypt_setkey+0x1d7/0x980 drivers/md/dm-crypt.c:2417
Code: 14 24 4c 8b b2 58 06 00 00 8b 5c 24 0c 29 eb 49 8d 7e 04 41 89 df 41 0f cf 48 89 f8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df <42> 0f b6 04 20 84 c0 0f 85 00 07 00 00 45 89 7e 04 4c 89 f0 48 c1
RSP: 0018:ffffc90003aef670 EFLAGS: 00010247
RAX: 0000000000000000 RBX: 0000000000000010 RCX: ffff888030aa4b00
RDX: ffff888035b3f000 RSI: 0000000000000020 RDI: 0000000000000004
RBP: 0000000000000020 R08: ffff888035b3f12f R09: 1ffff11006b67e25
R10: dffffc0000000000 R11: ffffed1006b67e26 R12: dffffc0000000000
R13: ffff888035b3f120 R14: 0000000000000000 R15: 0000000010000000
FS:  0000555578d00500(0000) GS:ffff88808ac1d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f841a4e84ac CR3: 0000000038575000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 crypt_set_key+0x3a0/0x680 drivers/md/dm-crypt.c:2642
 crypt_ctr_cipher drivers/md/dm-crypt.c:3067 [inline]
 crypt_ctr+0x2437/0x3c20 drivers/md/dm-crypt.c:3254
 dm_table_add_target+0x58d/0xc70 drivers/md/dm-table.c:749
 populate_table drivers/md/dm-ioctl.c:1602 [inline]
 table_load+0x325/0x8a0 drivers/md/dm-ioctl.c:1645
 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline]
 dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7fae39f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd11f4b518 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7fae625fa0 RCX: 00007f7fae39f559
RDX: 0000200000000540 RSI: 00000000c138fd09 RDI: 0000000000000003
RBP: 00007f7fae436b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7fae625fac R14: 00007f7fae625fa0 R15: 00007f7fae625fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:crypt_copy_authenckey drivers/md/dm-crypt.c:2396 [inline]
RIP: 0010:crypt_setkey+0x1d7/0x980 drivers/md/dm-crypt.c:2417
Code: 14 24 4c 8b b2 58 06 00 00 8b 5c 24 0c 29 eb 49 8d 7e 04 41 89 df 41 0f cf 48 89 f8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df <42> 0f b6 04 20 84 c0 0f 85 00 07 00 00 45 89 7e 04 4c 89 f0 48 c1
RSP: 0018:ffffc90003aef670 EFLAGS: 00010247
RAX: 0000000000000000 RBX: 0000000000000010 RCX: ffff888030aa4b00
RDX: ffff888035b3f000 RSI: 0000000000000020 RDI: 0000000000000004
RBP: 0000000000000020 R08: ffff888035b3f12f R09: 1ffff11006b67e25
R10: dffffc0000000000 R11: ffffed1006b67e26 R12: dffffc0000000000
R13: ffff888035b3f120 R14: 0000000000000000 R15: 0000000010000000
FS:  0000555578d00500(0000) GS:ffff88808ac1d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f841a650286 CR3: 0000000038575000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	14 24                	adc    $0x24,%al
   2:	4c 8b b2 58 06 00 00 	mov    0x658(%rdx),%r14
   9:	8b 5c 24 0c          	mov    0xc(%rsp),%ebx
   d:	29 eb                	sub    %ebp,%ebx
   f:	49 8d 7e 04          	lea    0x4(%r14),%rdi
  13:	41 89 df             	mov    %ebx,%r15d
  16:	41 0f cf             	bswap  %r15d
  19:	48 89 f8             	mov    %rdi,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  27:	fc ff df
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 00 07 00 00    	jne    0x737
  37:	45 89 7e 04          	mov    %r15d,0x4(%r14)
  3b:	4c 89 f0             	mov    %r14,%rax
  3e:	48                   	rex.W
  3f:	c1                   	.byte 0xc1


---
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