UBSAN: shift-out-of-bounds in dummy_hub

UBSAN: shift-out-of-bounds in dummy_hub_control
Status: fixed on 2021/03/10 01:48
Reported-by: syzbot+5925509f78293baa7331@syzkaller.appspotmail.com
Fix commit: c318840f USB: Gadget: dummy-hcd: Fix shift-out-of-bounds bug
First crash: 113d, last: 111d

Cause bisection: introduced by (bisect log) :
commit 8442b02bf3c6770e0d7e7ea17be36c30e95987b6
Author: Andrey Konovalov <andreyknvl@google.com>
Date: Mon Oct 21 14:20:58 2019 +0000

USB: dummy-hcd: increase max number of devices to 32

Crash: UBSAN: undefined-behaviour in dummy_hub_control (log)
Repro: C syz .config

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2020/12/29 16:43	16m	stern@rowland.harvard.edu	patch	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git e37b12e4	OK

Sample crash report:

================================================================================
UBSAN: shift-out-of-bounds in drivers/usb/gadget/udc/dummy_hcd.c:2293:33
shift exponent 257 is too large for 32-bit type 'int'
CPU: 0 PID: 8526 Comm: syz-executor949 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:395
 dummy_hub_control.cold+0x1a/0xbc drivers/usb/gadget/udc/dummy_hcd.c:2293
 rh_call_control drivers/usb/core/hcd.c:683 [inline]
 rh_urb_enqueue drivers/usb/core/hcd.c:841 [inline]
 usb_hcd_submit_urb+0xcaa/0x22d0 drivers/usb/core/hcd.c:1544
 usb_submit_urb+0x6e4/0x1560 drivers/usb/core/urb.c:585
 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+0x4cb/0x9c0 drivers/usb/core/devio.c:1165
 proc_control drivers/usb/core/devio.c:1191 [inline]
 usbdev_do_ioctl drivers/usb/core/devio.c:2535 [inline]
 usbdev_ioctl+0x12c1/0x3b20 drivers/usb/core/devio.c:2708
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x443f29
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc10df4328 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000443f29
RDX: 0000000020000000 RSI: 00000000c0185500 RDI: 0000000000000003
RBP: 00000000006ce018 R08: 0000000000000000 R09: 00000000004002e0
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000401bb0
R13: 0000000000401c40 R14: 0000000000000000 R15: 0000000000000000
================================================================================

Crashes (5):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info
ci-upstream-kasan-gce	2020/12/21 20:17	upstream	e37b12e4	04201c06	.config	log	report	syz	C
ci-upstream-kasan-gce	2020/12/23 08:52	upstream	614cb589	04201c06	.config	log	report			info
ci-upstream-kasan-gce	2020/12/22 00:24	upstream	e37b12e4	04201c06	.config	log	report			info
ci-upstream-kasan-gce	2020/12/21 20:00	upstream	e37b12e4	04201c06	.config	log	report			info
ci-upstream-kasan-gce-386	2020/12/22 00:28	upstream	e37b12e4	04201c06	.config	log	report			info