ghsa-cvqf-8622-79m2
Vulnerability from github
Published
2024-08-21 09:31
Modified
2024-09-06 15:32
Details

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: ... 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.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2022-48869"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-08-21T07:15:04Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: gadgetfs: Fix race between mounting and unmounting\n\nThe syzbot fuzzer and Gerald Lee have identified a use-after-free bug\nin the gadgetfs driver, involving processes concurrently mounting and\nunmounting the gadgetfs filesystem.  In particular, gadgetfs_fill_super()\ncan race with gadgetfs_kill_sb(), causing the latter to deallocate\nthe_device while the former is using it.  The output from KASAN says,\nin part:\n\nBUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline]\nBUG: KASAN: use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]\nBUG: KASAN: use-after-free in __refcount_sub_and_test include/linux/refcount.h:272 [inline]\nBUG: KASAN: use-after-free in __refcount_dec_and_test include/linux/refcount.h:315 [inline]\nBUG: KASAN: use-after-free in refcount_dec_and_test include/linux/refcount.h:333 [inline]\nBUG: KASAN: use-after-free in put_dev drivers/usb/gadget/legacy/inode.c:159 [inline]\nBUG: KASAN: use-after-free in gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086\nWrite of size 4 at addr ffff8880276d7840 by task syz-executor126/18689\n\nCPU: 0 PID: 18689 Comm: syz-executor126 Not tainted 6.1.0-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022\nCall Trace:\n \u003cTASK\u003e\n...\n atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]\n __refcount_sub_and_test include/linux/refcount.h:272 [inline]\n __refcount_dec_and_test include/linux/refcount.h:315 [inline]\n refcount_dec_and_test include/linux/refcount.h:333 [inline]\n put_dev drivers/usb/gadget/legacy/inode.c:159 [inline]\n gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086\n deactivate_locked_super+0xa7/0xf0 fs/super.c:332\n vfs_get_super fs/super.c:1190 [inline]\n get_tree_single+0xd0/0x160 fs/super.c:1207\n vfs_get_tree+0x88/0x270 fs/super.c:1531\n vfs_fsconfig_locked fs/fsopen.c:232 [inline]\n\nThe simplest solution is to ensure that gadgetfs_fill_super() and\ngadgetfs_kill_sb() are serialized by making them both acquire a new\nmutex.",
  "id": "GHSA-cvqf-8622-79m2",
  "modified": "2024-09-06T15:32:56Z",
  "published": "2024-08-21T09:31:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-48869"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/616fd34d017000ecf9097368b13d8a266f4920b3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/856e4b5e53f21edbd15d275dde62228dd94fb2b4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9a39f4626b361ee7aa10fd990401c37ec3b466ae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a2e075f40122d8daf587db126c562a67abd69cf9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d18dcfe9860e842f394e37ba01ca9440ab2178f4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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