CVE-2021-47582

published 2024-06-19

CVE-2021-47582: 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…

Priority P4 19 medium 5.5 CVSS 3.1

AV L AC L PR L UI N S U C N I N A H

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.

Affected

8 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.15.15-1 (bookworm)	linux 5.15.15-1 (bookworm)
linux	linux	—	—
linux	linux	>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 403716741c6c2c510dce44e88f085a740f535de6	403716741c6c2c510dce44e88f085a740f535de6
linux	linux	>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ae8709b296d80c7f45aa1f35c0e7659ad69edce1	ae8709b296d80c7f45aa1f35c0e7659ad69edce1
linux	linux_kernel	< 5.15.11	5.15.11
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1

CVSS provenance

nvd v3.1 5.5 MEDIUM CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv 5.5 MEDIUM

vendor_debian 5.5 MEDIUM

vendor_redhat 5.5 MEDIUM

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