Re: [syzbot] [wireless] BUG: unable to handle kernel paging request in ieee80211_wep_encrypt

[Eric Biggers <ebiggers@kernel.org>]

[+linux-wireless and Johannes for ieee80211_wep_encrypt]

On Thu, Jul 17, 2025 at 03:15:37AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    5e28d5a3f774 net/sched: sch_qfq: Fix race condition on qfq..
> git tree:       net
> console output: https://syzkaller.appspot.com/x/log.txt?x=146550f0580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b309c907eaab29da
> dashboard link: https://syzkaller.appspot.com/bug?extid=d1008c24929007591b6b
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/897daa1d604c/disk-5e28d5a3.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/0d5527eee75d/vmlinux-5e28d5a3.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/31ee968efcd7/bzImage-5e28d5a3.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+d1008c24929007591b6b@syzkaller.appspotmail.com
> 
> BUG: unable to handle page fault for address: ffff8880bfffd000
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 1a201067 P4D 1a201067 PUD 23ffff067 PMD 23fffe067 PTE 0
> Oops: Oops: 0000 [#1] SMP KASAN PTI
> CPU: 1 UID: 0 PID: 8097 Comm: syz.1.594 Not tainted 6.16.0-rc5-syzkaller-00183-g5e28d5a3f774 #0 PREEMPT(full) 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
> RIP: 0010:crc32_lsb_pclmul_sse+0x8f/0x220 arch/x86/lib/crc32-pclmul.S:6
> Code: 0f 3a 44 c7 11 66 0f ef ec 66 0f ef c5 f3 0f 6f 66 10 66 0f 6f e9 66 0f 3a 44 ef 00 66 0f 3a 44 cf 11 66 0f ef ec 66 0f ef cd <f3> 0f 6f 66 20 66 0f 6f ea 66 0f 3a 44 ef 00 66 0f 3a 44 d7 11 66
> RSP: 0018:ffffc9001bcae6f8 EFLAGS: 00010296
> RAX: e4cc01b02de40500 RBX: fffffffffffffffe RCX: ffffffff8be53dc0
> RDX: ffffffff7301ca7e RSI: ffff8880bfffcfde RDI: 00000000ffffffff
> RBP: 00000000ffffffff R08: ffff88801cb09e07 R09: 1ffff110039613c0
> R10: dffffc0000000000 R11: ffffed10039613c1 R12: fffffffffffffffe
> R13: ffff888033019a5e R14: ffff888033019a5e R15: ffff888067eeec80
> FS:  00007f4779be36c0(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffff8880bfffd000 CR3: 00000000671a8000 CR4: 00000000003526f0
> Call Trace:
>  <TASK>
>  crc32_le_arch+0x56/0xa0 arch/x86/lib/crc32.c:21
>  crc32_le include/linux/crc32.h:18 [inline]
>  ieee80211_wep_encrypt_data net/mac80211/wep.c:114 [inline]
>  ieee80211_wep_encrypt+0x228/0x410 net/mac80211/wep.c:158
>  wep_encrypt_skb net/mac80211/wep.c:277 [inline]
>  ieee80211_crypto_wep_encrypt+0x1f6/0x320 net/mac80211/wep.c:300
>  invoke_tx_handlers_late+0x1145/0x1820 net/mac80211/tx.c:1846
>  ieee80211_tx_dequeue+0x3068/0x4340 net/mac80211/tx.c:3916
>  wake_tx_push_queue net/mac80211/util.c:294 [inline]
>  ieee80211_handle_wake_tx_queue+0x125/0x2a0 net/mac80211/util.c:315
>  drv_wake_tx_queue net/mac80211/driver-ops.h:1367 [inline]
>  schedule_and_wake_txq net/mac80211/driver-ops.h:1374 [inline]
>  ieee80211_queue_skb+0x19e8/0x2180 net/mac80211/tx.c:1648
>  ieee80211_tx+0x297/0x420 net/mac80211/tx.c:1951
>  __ieee80211_tx_skb_tid_band+0x50f/0x680 net/mac80211/tx.c:6103
>  ieee80211_tx_skb_tid+0x266/0x420 net/mac80211/tx.c:6131
>  ieee80211_mgmt_tx+0x1c25/0x21d0 net/mac80211/offchannel.c:1023
>  rdev_mgmt_tx net/wireless/rdev-ops.h:762 [inline]
>  cfg80211_mlme_mgmt_tx+0x7f2/0x1620 net/wireless/mlme.c:938
>  nl80211_tx_mgmt+0x9fd/0xd50 net/wireless/nl80211.c:12921
>  genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
>  genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
>  genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
>  netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
>  genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
>  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
>  netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1346
>  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
>  sock_sendmsg_nosec net/socket.c:712 [inline]
>  __sock_sendmsg+0x219/0x270 net/socket.c:727
>  ____sys_sendmsg+0x505/0x830 net/socket.c:2566
>  ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
>  __sys_sendmsg net/socket.c:2652 [inline]
>  __do_sys_sendmsg net/socket.c:2657 [inline]
>  __se_sys_sendmsg net/socket.c:2655 [inline]
>  __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2655
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f4778d8e929
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f4779be3038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f4778fb6080 RCX: 00007f4778d8e929
> RDX: 0000000024008080 RSI: 0000200000000c00 RDI: 0000000000000005
> RBP: 00007f4778e10b39 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f4778fb6080 R15: 00007ffff7e551c8
>  </TASK>
> Modules linked in:
> CR2: ffff8880bfffd000
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:crc32_lsb_pclmul_sse+0x8f/0x220 arch/x86/lib/crc32-pclmul.S:6
> Code: 0f 3a 44 c7 11 66 0f ef ec 66 0f ef c5 f3 0f 6f 66 10 66 0f 6f e9 66 0f 3a 44 ef 00 66 0f 3a 44 cf 11 66 0f ef ec 66 0f ef cd <f3> 0f 6f 66 20 66 0f 6f ea 66 0f 3a 44 ef 00 66 0f 3a 44 d7 11 66
> RSP: 0018:ffffc9001bcae6f8 EFLAGS: 00010296
> RAX: e4cc01b02de40500 RBX: fffffffffffffffe RCX: ffffffff8be53dc0
> RDX: ffffffff7301ca7e RSI: ffff8880bfffcfde RDI: 00000000ffffffff
> RBP: 00000000ffffffff R08: ffff88801cb09e07 R09: 1ffff110039613c0
> R10: dffffc0000000000 R11: ffffed10039613c1 R12: fffffffffffffffe
> R13: ffff888033019a5e R14: ffff888033019a5e R15: ffff888067eeec80
> FS:  00007f4779be36c0(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffff8880bfffd000 CR3: 00000000671a8000 CR4: 00000000003526f0
> ----------------
> Code disassembly (best guess), 1 bytes skipped:
>    0:	3a 44 c7 11          	cmp    0x11(%rdi,%rax,8),%al
>    4:	66 0f ef ec          	pxor   %xmm4,%xmm5
>    8:	66 0f ef c5          	pxor   %xmm5,%xmm0
>    c:	f3 0f 6f 66 10       	movdqu 0x10(%rsi),%xmm4
>   11:	66 0f 6f e9          	movdqa %xmm1,%xmm5
>   15:	66 0f 3a 44 ef 00    	pclmullqlqdq %xmm7,%xmm5
>   1b:	66 0f 3a 44 cf 11    	pclmulhqhqdq %xmm7,%xmm1
>   21:	66 0f ef ec          	pxor   %xmm4,%xmm5
>   25:	66 0f ef cd          	pxor   %xmm5,%xmm1
> * 29:	f3 0f 6f 66 20       	movdqu 0x20(%rsi),%xmm4 <-- trapping instruction
>   2e:	66 0f 6f ea          	movdqa %xmm2,%xmm5
>   32:	66 0f 3a 44 ef 00    	pclmullqlqdq %xmm7,%xmm5
>   38:	66 0f 3a 44 d7 11    	pclmulhqhqdq %xmm7,%xmm2
>   3e:	66                   	data16
> 
> 
> ---
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syzbot assigned this to the "crypto" subsystem.  However, the crash
happened in crc32_le() which is not part of the crypto subsystem.  Also,
crc32_le() is well-tested (e.g. by crc_kunit), and the bug is unlikely
to be there.  Rather, the calling code in ieee80211_wep_encrypt_data()
is passing an invalid data buffer to crc32_le().  So let's do:

#syz set subsystems: wireless