USB: gadgetfs: Fix race between mounting and unmounting
The syzbot fuzzer and Gerald Lee have identified a use-after-free bug
in the gadgetfs driver, involving processes concurrently mounting and
unmounting the gadgetfs filesystem. In particular, gadgetfs_fill_super()
can race with gadgetfs_kill_sb(), causing the latter to deallocate
the_device while the former is using it. The output from KASAN says,
in part:
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
BUG: KASAN: use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]
BUG: KASAN: use-after-free in __refcount_sub_and_test include/linux/refcount.h:272 [inline]
BUG: KASAN: use-after-free in __refcount_dec_and_test include/linux/refcount.h:315 [inline]
BUG: KASAN: use-after-free in refcount_dec_and_test include/linux/refcount.h:333 [inline]
BUG: KASAN: use-after-free in put_dev drivers/usb/gadget/legacy/inode.c:159 [inline]
BUG: KASAN: use-after-free in gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086
Write of size 4 at addr ffff8880276d7840 by task syz-executor126/18689
CPU: 0 PID: 18689 Comm: syz-executor126 Not tainted 6.1.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
...
atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]
__refcount_sub_and_test include/linux/refcount.h:272 [inline]
__refcount_dec_and_test include/linux/refcount.h:315 [inline]
refcount_dec_and_test include/linux/refcount.h:333 [inline]
put_dev drivers/usb/gadget/legacy/inode.c:159 [inline]
gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086
deactivate_locked_super+0xa7/0xf0 fs/super.c:332
vfs_get_super fs/super.c:1190 [inline]
get_tree_single+0xd0/0x160 fs/super.c:1207
vfs_get_tree+0x88/0x270 fs/super.c:1531
vfs_fsconfig_locked fs/fsopen.c:232 [inline]
The simplest solution is to ensure that gadgetfs_fill_super() and
gadgetfs_kill_sb() are serialized by making them both acquire a new
mutex.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
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Wed, 11 Sep 2024 13:30:00 +0000
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| Metrics |
ssvc
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Fri, 06 Sep 2024 14:45:00 +0000
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| First Time appeared |
Linux
Linux linux Kernel |
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| Weaknesses | CWE-416 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
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| Metrics |
cvssV3_1
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cvssV3_1
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Wed, 21 Aug 2024 21:00:00 +0000
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| Metrics |
threat_severity
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cvssV3_1
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Wed, 21 Aug 2024 06:30:00 +0000
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| Description | In the Linux kernel, the following vulnerability has been resolved: USB: gadgetfs: Fix race between mounting and unmounting The syzbot fuzzer and Gerald Lee have identified a use-after-free bug in the gadgetfs driver, involving processes concurrently mounting and unmounting the gadgetfs filesystem. In particular, gadgetfs_fill_super() can race with gadgetfs_kill_sb(), causing the latter to deallocate the_device while the former is using it. The output from KASAN says, in part: BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline] BUG: KASAN: use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline] BUG: KASAN: use-after-free in __refcount_sub_and_test include/linux/refcount.h:272 [inline] BUG: KASAN: use-after-free in __refcount_dec_and_test include/linux/refcount.h:315 [inline] BUG: KASAN: use-after-free in refcount_dec_and_test include/linux/refcount.h:333 [inline] BUG: KASAN: use-after-free in put_dev drivers/usb/gadget/legacy/inode.c:159 [inline] BUG: KASAN: use-after-free in gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086 Write of size 4 at addr ffff8880276d7840 by task syz-executor126/18689 CPU: 0 PID: 18689 Comm: syz-executor126 Not tainted 6.1.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: <TASK> ... atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline] __refcount_sub_and_test include/linux/refcount.h:272 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] put_dev drivers/usb/gadget/legacy/inode.c:159 [inline] gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086 deactivate_locked_super+0xa7/0xf0 fs/super.c:332 vfs_get_super fs/super.c:1190 [inline] get_tree_single+0xd0/0x160 fs/super.c:1207 vfs_get_tree+0x88/0x270 fs/super.c:1531 vfs_fsconfig_locked fs/fsopen.c:232 [inline] The simplest solution is to ensure that gadgetfs_fill_super() and gadgetfs_kill_sb() are serialized by making them both acquire a new mutex. | |
| Title | USB: gadgetfs: Fix race between mounting and unmounting | |
| References |
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T18:48:43.958Z
Reserved: 2024-07-16T11:38:08.921Z
Link: CVE-2022-48869
Updated: 2024-09-11T12:42:11.953Z
Status : Analyzed
Published: 2024-08-21T07:15:04.080
Modified: 2024-09-06T14:19:58.030
Link: CVE-2022-48869
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