ghsa-2x2w-mp33-7x7m
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
f2fs: don't reset unchangable mount option in f2fs_remount()
syzbot reports a bug as below:
general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN RIP: 0010:__lock_acquire+0x69/0x2000 kernel/locking/lockdep.c:4942 Call Trace: lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5691 __raw_write_lock include/linux/rwlock_api_smp.h:209 [inline] _raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300 __drop_extent_tree+0x3ac/0x660 fs/f2fs/extent_cache.c:1100 f2fs_drop_extent_tree+0x17/0x30 fs/f2fs/extent_cache.c:1116 f2fs_insert_range+0x2d5/0x3c0 fs/f2fs/file.c:1664 f2fs_fallocate+0x4e4/0x6d0 fs/f2fs/file.c:1838 vfs_fallocate+0x54b/0x6b0 fs/open.c:324 ksys_fallocate fs/open.c:347 [inline] __do_sys_fallocate fs/open.c:355 [inline] __se_sys_fallocate fs/open.c:353 [inline] __x64_sys_fallocate+0xbd/0x100 fs/open.c:353 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
The root cause is race condition as below: - since it tries to remount rw filesystem, so that do_remount won't call sb_prepare_remount_readonly to block fallocate, there may be race condition in between remount and fallocate. - in f2fs_remount(), default_options() will reset mount option to default one, and then update it based on result of parse_options(), so there is a hole which race condition can happen.
Thread A Thread B - f2fs_fill_super - parse_options - clear_opt(READ_EXTENT_CACHE)
- f2fs_remount
- default_options
- set_opt(READ_EXTENT_CACHE) - f2fs_fallocate - f2fs_insert_range - f2fs_drop_extent_tree - __drop_extent_tree - __may_extent_tree - test_opt(READ_EXTENT_CACHE) return true - write_lock(&et->lock) access NULL pointer
- parse_options
- clear_opt(READ_EXTENT_CACHE)
{
"affected": [],
"aliases": [
"CVE-2023-53447"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-18T16:15:49Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: don\u0027t reset unchangable mount option in f2fs_remount()\n\nsyzbot reports a bug as below:\n\ngeneral protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN\nRIP: 0010:__lock_acquire+0x69/0x2000 kernel/locking/lockdep.c:4942\nCall Trace:\n lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5691\n __raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]\n _raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300\n __drop_extent_tree+0x3ac/0x660 fs/f2fs/extent_cache.c:1100\n f2fs_drop_extent_tree+0x17/0x30 fs/f2fs/extent_cache.c:1116\n f2fs_insert_range+0x2d5/0x3c0 fs/f2fs/file.c:1664\n f2fs_fallocate+0x4e4/0x6d0 fs/f2fs/file.c:1838\n vfs_fallocate+0x54b/0x6b0 fs/open.c:324\n ksys_fallocate fs/open.c:347 [inline]\n __do_sys_fallocate fs/open.c:355 [inline]\n __se_sys_fallocate fs/open.c:353 [inline]\n __x64_sys_fallocate+0xbd/0x100 fs/open.c:353\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe root cause is race condition as below:\n- since it tries to remount rw filesystem, so that do_remount won\u0027t\ncall sb_prepare_remount_readonly to block fallocate, there may be race\ncondition in between remount and fallocate.\n- in f2fs_remount(), default_options() will reset mount option to default\none, and then update it based on result of parse_options(), so there is\na hole which race condition can happen.\n\nThread A\t\t\tThread B\n- f2fs_fill_super\n - parse_options\n - clear_opt(READ_EXTENT_CACHE)\n\n- f2fs_remount\n - default_options\n - set_opt(READ_EXTENT_CACHE)\n\t\t\t\t- f2fs_fallocate\n\t\t\t\t - f2fs_insert_range\n\t\t\t\t - f2fs_drop_extent_tree\n\t\t\t\t - __drop_extent_tree\n\t\t\t\t - __may_extent_tree\n\t\t\t\t - test_opt(READ_EXTENT_CACHE) return true\n\t\t\t\t - write_lock(\u0026et-\u003elock) access NULL pointer\n - parse_options\n - clear_opt(READ_EXTENT_CACHE)",
"id": "GHSA-2x2w-mp33-7x7m",
"modified": "2025-09-18T18:30:28Z",
"published": "2025-09-18T18:30:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53447"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/115557cc226a927924f2d7d1980ccbf6e3b3bb36"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/458c15dfbce62c35fefd9ca637b20a051309c9f1"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
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