[syzbot] [usb?] general protection fault in usbtest_probe

[syzbot] [usb?] general protection fault in usbtest_probe

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3b5f4b83c4ab Merge tag 'for-7.2-rc5-tag' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12eee7b1580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=7e1e5911f9eac50bedc7
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12f41449580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1797249e580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-3b5f4b83.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ed6d6b480fd7/vmlinux-3b5f4b83.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5a591a74024/bzImage-3b5f4b83.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7e1e5911f9eac50bedc7@syzkaller.appspotmail.com

usb 5-1: New USB device found, idVendor=0547, idProduct=2235, bcdDevice= 0.00
usb 5-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 5-1: Product: syz
usb 5-1: Manufacturer: syz
usb 5-1: SerialNumber: syz
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 UID: 0 PID: 29 Comm: kworker/1:0 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
Workqueue: usb_hub_wq hub_event
RIP: 0010:usbtest_probe+0x3b9/0x1280 drivers/usb/misc/usbtest.c:2822
Code: e9 46 fa 45 85 ff 79 5e e8 34 ef 46 fa 48 8b 84 24 80 00 00 00 48 8d 58 0a 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 04 02 48 89 da 83 e2 07 38 d0 7f 08 84 c0 0f 85 58 0d 00 00
RSP: 0018:ffffc90000686fc8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 000000000000000a RCX: ffffffff87c37102
RDX: 0000000000000001 RSI: ffffffff87c3710c RDI: ffff88801f69a540
RBP: ffff88802bf65910 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffff R11: 000000000000758b R12: ffff88816db048b0
R13: ffff88803724fed0 R14: ffff88803724fe00 R15: 00000000ffffffff
FS:  0000000000000000(0000) GS:ffff8880d5edc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87747eb580 CR3: 000000002ad51000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3772
 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3772
 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695
 hub_port_connect drivers/usb/core/hub.c:5567 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x30a3/0x4a60 drivers/usb/core/hub.c:5953
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:usbtest_probe+0x3b9/0x1280 drivers/usb/misc/usbtest.c:2822
Code: e9 46 fa 45 85 ff 79 5e e8 34 ef 46 fa 48 8b 84 24 80 00 00 00 48 8d 58 0a 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 04 02 48 89 da 83 e2 07 38 d0 7f 08 84 c0 0f 85 58 0d 00 00
RSP: 0018:ffffc90000686fc8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 000000000000000a RCX: ffffffff87c37102
RDX: 0000000000000001 RSI: ffffffff87c3710c RDI: ffff88801f69a540
RBP: ffff88802bf65910 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffff R11: 000000000000758b R12: ffff88816db048b0
R13: ffff88803724fed0 R14: ffff88803724fe00 R15: 00000000ffffffff
FS:  0000000000000000(0000) GS:ffff8880d5edc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87747eb580 CR3: 000000002a8fe000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	46 fa                	rex.RX cli
   2:	45 85 ff             	test   %r15d,%r15d
   5:	79 5e                	jns    0x65
   7:	e8 34 ef 46 fa       	call   0xfa46ef40
   c:	48 8b 84 24 80 00 00 	mov    0x80(%rsp),%rax
  13:	00
  14:	48 8d 58 0a          	lea    0xa(%rax),%rbx
  18:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1f:	fc ff df
  22:	48 89 da             	mov    %rbx,%rdx
  25:	48 c1 ea 03          	shr    $0x3,%rdx
* 29:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2d:	48 89 da             	mov    %rbx,%rdx
  30:	83 e2 07             	and    $0x7,%edx
  33:	38 d0                	cmp    %dl,%al
  35:	7f 08                	jg     0x3f
  37:	84 c0                	test   %al,%al
  39:	0f 85 58 0d 00 00    	jne    0xd97


---
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Forwarded: [PATCH v2 test] usb: usbtest: disable dynamic ID support

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH v2 test] usb: usbtest: disable dynamic ID support
Author: nogikh@google.com

#syz test

The usbtest driver relies on the driver_info field of struct usb_device_id
to point to a valid struct usbtest_info descriptor. This structure contains
essential test configurations, such as endpoint addresses and test modes,
which are required during probe.

When a user dynamically adds a new device ID via the sysfs new_id
interface without specifying a reference device, the USB core initializes
driver_info to 0 (NULL). When a matching device is subsequently probed,
usbtest_probe() unconditionally casts driver_info to a struct usbtest_info
pointer and dereferences it, leading to a NULL pointer dereference crash:

  Oops: general protection fault, probably for non-canonical address
  0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
  RIP: 0010:usbtest_probe+0x3b9/0x1280 drivers/usb/misc/usbtest.c:2822

Because usbtest strictly requires pre-defined usbtest_info descriptors
to function, dynamic ID binding via sysfs is fundamentally unsupported
for this driver.

Fix this by setting .no_dynamic_id = 1 on usbtest_driver. This instructs
the USB core to skip creating the new_id and remove_id sysfs interfaces
for usbtest, preventing invalid dynamic ID entries from being created.

Reported-by: syzbot+7e1e5911f9eac50bedc7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7e1e5911f9eac50bedc7
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
---
Changes in v2:
- Disable dynamic IDs via .no_dynamic_id = 1 instead of adding a runtime NULL
  check in probe().
- Link to v1: https://lore.kernel.org/r/2650cf0f-26f9-48b5-b198-e4cb67c59cf0@mail.kernel.org

 drivers/usb/misc/usbtest.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index 98071b25ac076..8759df49be287 100644
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -3054,6 +3054,7 @@ static struct usb_driver usbtest_driver = {
 	.disconnect =	usbtest_disconnect,
 	.suspend =	usbtest_suspend,
 	.resume =	usbtest_resume,
+	.no_dynamic_id = 1,
 };
 
 /*-------------------------------------------------------------------------*/
-- 
base-commit: 48a5a7ab8d6ab7090564339e039c421f315de912
-- 
2.55.0.654.g21b8a5bc05-goog