[syzbot] UBSAN: array-index-out-of-bounds in ehci_hub_control

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d999ade1cc86 Merge tag 'perf-tools-fixes-for-v5.15-2021-10..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17d85d34b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=b5d8cfd89abd92bf
dashboard link: https://syzkaller.appspot.com/bug?extid=9df2568864dedf79db36
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9df256...@syzkaller.appspotmail.com

================================================================================
UBSAN: array-index-out-of-bounds in drivers/usb/host/ehci-hub.c:754:39
index 254 is out of range for type 'u32 [15]'
CPU: 0 PID: 11514 Comm: syz-executor.1 Not tainted 5.15.0-rc5-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
ubsan_epilogue+0xb/0x5a lib/ubsan.c:151
__ubsan_handle_out_of_bounds.cold+0x62/0x6c lib/ubsan.c:291
ehci_hub_control+0x22ad/0x2720 drivers/usb/host/ehci-hub.c:754
rh_call_control drivers/usb/core/hcd.c:683 [inline]
rh_urb_enqueue drivers/usb/core/hcd.c:841 [inline]
usb_hcd_submit_urb+0xcaf/0x22d0 drivers/usb/core/hcd.c:1544
usb_submit_urb+0x86d/0x18a0 drivers/usb/core/urb.c:594
usb_start_wait_urb+0x101/0x4c0 drivers/usb/core/message.c:58
usb_internal_control_msg drivers/usb/core/message.c:102 [inline]
usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:153
do_proc_control+0x40a/0x9f0 drivers/usb/core/devio.c:1165
proc_control drivers/usb/core/devio.c:1191 [inline]
usbdev_do_ioctl drivers/usb/core/devio.c:2540 [inline]
usbdev_ioctl+0x10e2/0x36c0 drivers/usb/core/devio.c:2713
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fdbaec43a39
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdbac1b9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdbaed46f60 RCX: 00007fdbaec43a39
RDX: 0000000020000000 RSI: 00000000c0185500 RDI: 0000000000000003
RBP: 00007fdbaec9dc5f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe5b9cffbf R14: 00007fdbac1b9300 R15: 0000000000022000
================================================================================


---
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[Alan Stern]

On Tue, Oct 19, 2021 at 01:44:24PM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: d999ade1cc86 Merge tag 'perf-tools-fixes-for-v5.15-2021-10..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17d85d34b00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=b5d8cfd89abd92bf
> dashboard link: https://syzkaller.appspot.com/bug?extid=9df2568864dedf79db36
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+9df256...@syzkaller.appspotmail.com
>
> ================================================================================
> UBSAN: array-index-out-of-bounds in drivers/usb/host/ehci-hub.c:754:39
> index 254 is out of range for type 'u32 [15]'
> CPU: 0 PID: 11514 Comm: syz-executor.1 Not tainted 5.15.0-rc5-syzkaller #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014

This should already be fixed by

https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/drivers/usb/host/ehci-hub.c?h=usb-next&id=846cbf98cbef20376b1a95fa3734c435543f3519

(although it can't be tested if there is no reproducer). That commit is
scheduled to go into 5.16-rc1.

This isn't really a bug, because the pointer doesn't get used in cases
where the index is beyond the end of the array.

Alan Stern

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.