ghsa-f5rq-w7xf-cjx9
Vulnerability from github
Published
2025-09-22 21:30
Modified
2025-09-22 21:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

watch_queue: Fix NULL dereference in error cleanup

In watch_queue_set_size(), the error cleanup code doesn't take account of the fact that __free_page() can't handle a NULL pointer when trying to free up buffer pages that did get allocated.

Fix this by only calling __free_page() on the pages actually allocated.

Without the fix, this can lead to something like the following:

BUG: KASAN: null-ptr-deref in __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473 Read of size 4 at addr 0000000000000034 by task syz-executor168/3599 ... Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 __kasan_report mm/kasan/report.c:446 [inline] kasan_report.cold+0x66/0xdf mm/kasan/report.c:459 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 instrument_atomic_read include/linux/instrumented.h:71 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] page_ref_count include/linux/page_ref.h:67 [inline] put_page_testzero include/linux/mm.h:717 [inline] __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473 watch_queue_set_size+0x499/0x630 kernel/watch_queue.c:275 pipe_ioctl+0xac/0x2b0 fs/pipe.c:632 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae

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{
  "affected": [],
  "aliases": [
    "CVE-2022-49257"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-26T07:01:02Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nwatch_queue: Fix NULL dereference in error cleanup\n\nIn watch_queue_set_size(), the error cleanup code doesn\u0027t take account of\nthe fact that __free_page() can\u0027t handle a NULL pointer when trying to free\nup buffer pages that did get allocated.\n\nFix this by only calling __free_page() on the pages actually allocated.\n\nWithout the fix, this can lead to something like the following:\n\nBUG: KASAN: null-ptr-deref in __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473\nRead of size 4 at addr 0000000000000034 by task syz-executor168/3599\n...\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\n __kasan_report mm/kasan/report.c:446 [inline]\n kasan_report.cold+0x66/0xdf mm/kasan/report.c:459\n check_region_inline mm/kasan/generic.c:183 [inline]\n kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189\n instrument_atomic_read include/linux/instrumented.h:71 [inline]\n atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]\n page_ref_count include/linux/page_ref.h:67 [inline]\n put_page_testzero include/linux/mm.h:717 [inline]\n __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473\n watch_queue_set_size+0x499/0x630 kernel/watch_queue.c:275\n pipe_ioctl+0xac/0x2b0 fs/pipe.c:632\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:874 [inline]\n __se_sys_ioctl fs/ioctl.c:860 [inline]\n __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae",
  "id": "GHSA-f5rq-w7xf-cjx9",
  "modified": "2025-09-22T21:30:16Z",
  "published": "2025-09-22T21:30:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49257"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/112a2f9b0a8457794095a0450598f150724ec456"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5ae75b4ed30322b42abaa75ef1b784addfdb7dc9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/695c47cea02b9101e2fc2e7d36d552128592b347"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a635415a064e77bcfbf43da413fd9dfe0bbed9cb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b6f5ad3e45d19f9c4ee3e8a2aff829f28d68591d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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