Description

In the Linux kernel, the following vulnerability has been resolved: USB: core: Make do_proc_control() and do_proc_bulk() killable The USBDEVFS_CONTROL and USBDEVFS_BULK ioctls invoke usb_start_wait_urb(), which contains an uninterruptible wait with a user-specified timeout value. If timeout value is very large and the device being accessed does not respond in a reasonable amount of time, the kernel will complain about "Task X blocked for more than N seconds", as found in testing by syzbot: INFO: task syz-executor.0:8700 blocked for more than 143 seconds. Not tainted 5.14.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:23192 pid: 8700 ppid: 8455 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4681 [inline] __schedule+0xc07/0x11f0 kernel/sched/core.c:5938 schedule+0x14b/0x210 kernel/sched/core.c:6017 schedule_timeout+0x98/0x2f0 kernel/time/timer.c:1857 do_wait_for_common+0x2da/0x480 kernel/sched/completion.c:85 __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion_timeout+0x46/0x60 kernel/sched/completion.c:157 usb_start_wait_urb+0x167/0x550 drivers/usb/core/message.c:63 do_proc_bulk+0x978/0x1080 drivers/usb/core/devio.c:1236 proc_bulk drivers/usb/core/devio.c:1273 [inline] usbdev_do_ioctl drivers/usb/core/devio.c:2547 [inline] usbdev_ioctl+0x3441/0x6b10 drivers/usb/core/devio.c:2713 ... To fix this problem, this patch replaces usbfs's calls to usb_control_msg() and usb_bulk_msg() with special-purpose code that does essentially the same thing (as recommended in the comment for usb_start_wait_urb()), except that it always uses a killable wait and it uses GFP_KERNEL rather than GFP_NOIO.

Metrics

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

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CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

CVSS 2.0 Severity and Vector Strings:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

In the Linux kernel, the following vulnerability has been resolved:

USB: core: Make do_proc_control() and do_proc_bulk() killable

The USBDEVFS_CONTROL and USBDEVFS_BULK ioctls invoke
usb_start_wait_urb(), which contains an uninterruptible wait with a
user-specified timeout value.  If timeout value is very large and the
device being accessed does not respond in a reasonable amount of time,
the kernel will complain about "Task X blocked for more than N
seconds", as found in testing by syzbot:

I

kernel.org https://git.kernel.org/stable/c/403716741c6c2c510dce44e88f085a740f535de6 [No types assigned]

kernel.org https://git.kernel.org/stable/c/ae8709b296d80c7f45aa1f35c0e7659ad69edce1 [No types assigned]