ghsa-fq4p-236v-8g34
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid accessing uninitialized curseg
syzbot reports a f2fs bug as below:
F2FS-fs (loop3): Stopped filesystem due to reason: 7 kworker/u8:7: attempt to access beyond end of device BUG: unable to handle page fault for address: ffffed1604ea3dfa RIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline] RIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline] RIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline] RIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline] RIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649 f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline] f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156 wb_do_writeback fs/fs-writeback.c:2303 [inline] wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Commit 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") allows to trigger no free segment fault in allocator, then it will update curseg->segno to NULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed to check the flag, and access invalid curseg->segno directly in below call path, then resulting in panic:
- f2fs_write_inode
- f2fs_is_checkpoint_ready
- has_enough_free_secs
- has_not_enough_free_secs
- __get_secs_required
- has_curseg_enough_space
- get_ckpt_valid_blocks : access invalid curseg->segno
To avoid this issue, let's: - check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in f2fs_write_inode(). - in has_curseg_enough_space(), save curseg->segno into a temp variable, and verify its validation before use.
{
"affected": [],
"aliases": [
"CVE-2025-22123"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-16T15:16:06Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid accessing uninitialized curseg\n\nsyzbot reports a f2fs bug as below:\n\nF2FS-fs (loop3): Stopped filesystem due to reason: 7\nkworker/u8:7: attempt to access beyond end of device\nBUG: unable to handle page fault for address: ffffed1604ea3dfa\nRIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline]\nRIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline]\nRIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline]\nRIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline]\nRIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649\n \u003cTASK\u003e\n f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline]\n f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791\n write_inode fs/fs-writeback.c:1525 [inline]\n __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745\n writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976\n wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156\n wb_do_writeback fs/fs-writeback.c:2303 [inline]\n wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343\n process_one_work kernel/workqueue.c:3236 [inline]\n process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317\n worker_thread+0x870/0xd30 kernel/workqueue.c:3398\n kthread+0x7a9/0x920 kernel/kthread.c:464\n ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n\nCommit 8b10d3653735 (\"f2fs: introduce FAULT_NO_SEGMENT\") allows to trigger\nno free segment fault in allocator, then it will update curseg-\u003esegno to\nNULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed\nto check the flag, and access invalid curseg-\u003esegno directly in below call\npath, then resulting in panic:\n\n- f2fs_write_inode\n - f2fs_is_checkpoint_ready\n - has_enough_free_secs\n - has_not_enough_free_secs\n - __get_secs_required\n - has_curseg_enough_space\n - get_ckpt_valid_blocks\n : access invalid curseg-\u003esegno\n\nTo avoid this issue, let\u0027s:\n- check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in\nf2fs_write_inode().\n- in has_curseg_enough_space(), save curseg-\u003esegno into a temp variable,\nand verify its validation before use.",
"id": "GHSA-fq4p-236v-8g34",
"modified": "2025-06-10T12:30:17Z",
"published": "2025-04-16T15:34:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-22123"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7f90e5d423cd2d4c74b2abb527872f335108637f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/986c50f6bca109c6cf362b4e2babcb85aba958f6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bf49527089ec1ba894c6e587affabbfb2329f52e"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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