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.
CVSS Details
- CVSS 3.1 Base Score: 4.7
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Aug 22, 2024 | Aug 22, 2024 |
| Ubuntu | — | Upgrade linux-intel-iot-realtimeUpgrade linux-realtimeUpgrade linux-gcp-fipsUpgrade linux-intel-iotg-5.15Upgrade linux-raspi-5.4Upgrade linux-gkeop-5.15Upgrade linux-lowlatency-hwe-5.15Upgrade linux-iotUpgrade linux-gcpUpgrade linux-azure-5.4Upgrade linux-bluefieldUpgrade linux-gcp-5.4Upgrade linux-hwe-5.4Upgrade linux-awsUpgrade linux-gkeopUpgrade linux-fipsUpgrade linux-azure-5.15Upgrade linux-gcp-5.15Upgrade linux-kvmUpgrade linux-nvidiaUpgrade linux-ibmUpgrade linux-azure-fipsUpgrade linux-hwe-5.15Upgrade linux-lowlatencyUpgrade linux-xilinx-zynqmpUpgrade linux-intel-iotgUpgrade linux-azureUpgrade linux-ibm-5.4Upgrade linux-oracle-5.15Upgrade linux-riscv-5.15Upgrade linux-raspiUpgrade linux-oracleUpgrade linux-oracle-5.4Upgrade linux-gkeUpgrade linux-aws-5.15Upgrade linux-azure-fdeUpgrade linux-aws-fipsUpgrade linux-nvidia-tegra-5.15Upgrade linux-aws-5.4Upgrade linux | Nov 19, 2024 | Aug 21, 2024 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Aug 21, 2024 |
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