CVE-2025-40054 (GCVE-0-2025-40054)
Vulnerability from cvelistv5 – Published: 2025-10-28 11:48 – Updated: 2025-12-01 06:17
VLAI?
Summary
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix UAF issue in f2fs_merge_page_bio()
As JY reported in bugzilla [1],
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
pc : [0xffffffe51d249484] f2fs_is_cp_guaranteed+0x70/0x98
lr : [0xffffffe51d24adbc] f2fs_merge_page_bio+0x520/0x6d4
CPU: 3 UID: 0 PID: 6790 Comm: kworker/u16:3 Tainted: P B W OE 6.12.30-android16-5-maybe-dirty-4k #1 5f7701c9cbf727d1eebe77c89bbbeb3371e895e5
Tainted: [P]=PROPRIETARY_MODULE, [B]=BAD_PAGE, [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Workqueue: writeback wb_workfn (flush-254:49)
Call trace:
f2fs_is_cp_guaranteed+0x70/0x98
f2fs_inplace_write_data+0x174/0x2f4
f2fs_do_write_data_page+0x214/0x81c
f2fs_write_single_data_page+0x28c/0x764
f2fs_write_data_pages+0x78c/0xce4
do_writepages+0xe8/0x2fc
__writeback_single_inode+0x4c/0x4b4
writeback_sb_inodes+0x314/0x540
__writeback_inodes_wb+0xa4/0xf4
wb_writeback+0x160/0x448
wb_workfn+0x2f0/0x5dc
process_scheduled_works+0x1c8/0x458
worker_thread+0x334/0x3f0
kthread+0x118/0x1ac
ret_from_fork+0x10/0x20
[1] https://bugzilla.kernel.org/show_bug.cgi?id=220575
The panic was caused by UAF issue w/ below race condition:
kworker
- writepages
- f2fs_write_cache_pages
- f2fs_write_single_data_page
- f2fs_do_write_data_page
- f2fs_inplace_write_data
- f2fs_merge_page_bio
- add_inu_page
: cache page #1 into bio & cache bio in
io->bio_list
- f2fs_write_single_data_page
- f2fs_do_write_data_page
- f2fs_inplace_write_data
- f2fs_merge_page_bio
- add_inu_page
: cache page #2 into bio which is linked
in io->bio_list
write
- f2fs_write_begin
: write page #1
- f2fs_folio_wait_writeback
- f2fs_submit_merged_ipu_write
- f2fs_submit_write_bio
: submit bio which inclues page #1 and #2
software IRQ
- f2fs_write_end_io
- fscrypt_free_bounce_page
: freed bounced page which belongs to page #2
- inc_page_count( , WB_DATA_TYPE(data_folio), false)
: data_folio points to fio->encrypted_page
the bounced page can be freed before
accessing it in f2fs_is_cp_guarantee()
It can reproduce w/ below testcase:
Run below script in shell #1:
for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \
-c "pwrite 0 32k" -c "fdatasync"
Run below script in shell #2:
for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \
-c "pwrite 0 32k" -c "fdatasync"
So, in f2fs_merge_page_bio(), let's avoid using fio->encrypted_page after
commit page into internal ipu cache.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
{
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"product": "Linux",
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"descriptions": [
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix UAF issue in f2fs_merge_page_bio()\n\nAs JY reported in bugzilla [1],\n\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000000\npc : [0xffffffe51d249484] f2fs_is_cp_guaranteed+0x70/0x98\nlr : [0xffffffe51d24adbc] f2fs_merge_page_bio+0x520/0x6d4\nCPU: 3 UID: 0 PID: 6790 Comm: kworker/u16:3 Tainted: P B W OE 6.12.30-android16-5-maybe-dirty-4k #1 5f7701c9cbf727d1eebe77c89bbbeb3371e895e5\nTainted: [P]=PROPRIETARY_MODULE, [B]=BAD_PAGE, [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\nWorkqueue: writeback wb_workfn (flush-254:49)\nCall trace:\n f2fs_is_cp_guaranteed+0x70/0x98\n f2fs_inplace_write_data+0x174/0x2f4\n f2fs_do_write_data_page+0x214/0x81c\n f2fs_write_single_data_page+0x28c/0x764\n f2fs_write_data_pages+0x78c/0xce4\n do_writepages+0xe8/0x2fc\n __writeback_single_inode+0x4c/0x4b4\n writeback_sb_inodes+0x314/0x540\n __writeback_inodes_wb+0xa4/0xf4\n wb_writeback+0x160/0x448\n wb_workfn+0x2f0/0x5dc\n process_scheduled_works+0x1c8/0x458\n worker_thread+0x334/0x3f0\n kthread+0x118/0x1ac\n ret_from_fork+0x10/0x20\n\n[1] https://bugzilla.kernel.org/show_bug.cgi?id=220575\n\nThe panic was caused by UAF issue w/ below race condition:\n\nkworker\n- writepages\n - f2fs_write_cache_pages\n - f2fs_write_single_data_page\n - f2fs_do_write_data_page\n - f2fs_inplace_write_data\n - f2fs_merge_page_bio\n - add_inu_page\n : cache page #1 into bio \u0026 cache bio in\n io-\u003ebio_list\n - f2fs_write_single_data_page\n - f2fs_do_write_data_page\n - f2fs_inplace_write_data\n - f2fs_merge_page_bio\n - add_inu_page\n : cache page #2 into bio which is linked\n in io-\u003ebio_list\n\t\t\t\t\t\twrite\n\t\t\t\t\t\t- f2fs_write_begin\n\t\t\t\t\t\t: write page #1\n\t\t\t\t\t\t - f2fs_folio_wait_writeback\n\t\t\t\t\t\t - f2fs_submit_merged_ipu_write\n\t\t\t\t\t\t - f2fs_submit_write_bio\n\t\t\t\t\t\t : submit bio which inclues page #1 and #2\n\n\t\t\t\t\t\tsoftware IRQ\n\t\t\t\t\t\t- f2fs_write_end_io\n\t\t\t\t\t\t - fscrypt_free_bounce_page\n\t\t\t\t\t\t : freed bounced page which belongs to page #2\n - inc_page_count( , WB_DATA_TYPE(data_folio), false)\n : data_folio points to fio-\u003eencrypted_page\n the bounced page can be freed before\n accessing it in f2fs_is_cp_guarantee()\n\nIt can reproduce w/ below testcase:\nRun below script in shell #1:\nfor ((i=1;i\u003e0;i++)) do xfs_io -f /mnt/f2fs/enc/file \\\n-c \"pwrite 0 32k\" -c \"fdatasync\"\n\nRun below script in shell #2:\nfor ((i=1;i\u003e0;i++)) do xfs_io -f /mnt/f2fs/enc/file \\\n-c \"pwrite 0 32k\" -c \"fdatasync\"\n\nSo, in f2fs_merge_page_bio(), let\u0027s avoid using fio-\u003eencrypted_page after\ncommit page into internal ipu cache."
}
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"providerMetadata": {
"dateUpdated": "2025-12-01T06:17:01.773Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
{
"url": "https://git.kernel.org/stable/c/01118321e0c8a5f3ece57d0d377bfc92d83cd210"
},
{
"url": "https://git.kernel.org/stable/c/edf7e9040fc52c922db947f9c6c36f07377c52ea"
}
],
"title": "f2fs: fix UAF issue in f2fs_merge_page_bio()",
"x_generator": {
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}
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2025-40054",
"datePublished": "2025-10-28T11:48:29.073Z",
"dateReserved": "2025-04-16T07:20:57.157Z",
"dateUpdated": "2025-12-01T06:17:01.773Z",
"state": "PUBLISHED"
},
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"nvd": "{\"cve\":{\"id\":\"CVE-2025-40054\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-10-28T12:15:39.640\",\"lastModified\":\"2025-10-30T15:05:32.197\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nf2fs: fix UAF issue in f2fs_merge_page_bio()\\n\\nAs JY reported in bugzilla [1],\\n\\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000000\\npc : [0xffffffe51d249484] f2fs_is_cp_guaranteed+0x70/0x98\\nlr : [0xffffffe51d24adbc] f2fs_merge_page_bio+0x520/0x6d4\\nCPU: 3 UID: 0 PID: 6790 Comm: kworker/u16:3 Tainted: P B W OE 6.12.30-android16-5-maybe-dirty-4k #1 5f7701c9cbf727d1eebe77c89bbbeb3371e895e5\\nTainted: [P]=PROPRIETARY_MODULE, [B]=BAD_PAGE, [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\\nWorkqueue: writeback wb_workfn (flush-254:49)\\nCall trace:\\n f2fs_is_cp_guaranteed+0x70/0x98\\n f2fs_inplace_write_data+0x174/0x2f4\\n f2fs_do_write_data_page+0x214/0x81c\\n f2fs_write_single_data_page+0x28c/0x764\\n f2fs_write_data_pages+0x78c/0xce4\\n do_writepages+0xe8/0x2fc\\n __writeback_single_inode+0x4c/0x4b4\\n writeback_sb_inodes+0x314/0x540\\n __writeback_inodes_wb+0xa4/0xf4\\n wb_writeback+0x160/0x448\\n wb_workfn+0x2f0/0x5dc\\n process_scheduled_works+0x1c8/0x458\\n worker_thread+0x334/0x3f0\\n kthread+0x118/0x1ac\\n ret_from_fork+0x10/0x20\\n\\n[1] https://bugzilla.kernel.org/show_bug.cgi?id=220575\\n\\nThe panic was caused by UAF issue w/ below race condition:\\n\\nkworker\\n- writepages\\n - f2fs_write_cache_pages\\n - f2fs_write_single_data_page\\n - f2fs_do_write_data_page\\n - f2fs_inplace_write_data\\n - f2fs_merge_page_bio\\n - add_inu_page\\n : cache page #1 into bio \u0026 cache bio in\\n io-\u003ebio_list\\n - f2fs_write_single_data_page\\n - f2fs_do_write_data_page\\n - f2fs_inplace_write_data\\n - f2fs_merge_page_bio\\n - add_inu_page\\n : cache page #2 into bio which is linked\\n in io-\u003ebio_list\\n\\t\\t\\t\\t\\t\\twrite\\n\\t\\t\\t\\t\\t\\t- f2fs_write_begin\\n\\t\\t\\t\\t\\t\\t: write page #1\\n\\t\\t\\t\\t\\t\\t - f2fs_folio_wait_writeback\\n\\t\\t\\t\\t\\t\\t - f2fs_submit_merged_ipu_write\\n\\t\\t\\t\\t\\t\\t - f2fs_submit_write_bio\\n\\t\\t\\t\\t\\t\\t : submit bio which inclues page #1 and #2\\n\\n\\t\\t\\t\\t\\t\\tsoftware IRQ\\n\\t\\t\\t\\t\\t\\t- f2fs_write_end_io\\n\\t\\t\\t\\t\\t\\t - fscrypt_free_bounce_page\\n\\t\\t\\t\\t\\t\\t : freed bounced page which belongs to page #2\\n - inc_page_count( , WB_DATA_TYPE(data_folio), false)\\n : data_folio points to fio-\u003eencrypted_page\\n the bounced page can be freed before\\n accessing it in f2fs_is_cp_guarantee()\\n\\nIt can reproduce w/ below testcase:\\nRun below script in shell #1:\\nfor ((i=1;i\u003e0;i++)) do xfs_io -f /mnt/f2fs/enc/file \\\\\\n-c \\\"pwrite 0 32k\\\" -c \\\"fdatasync\\\"\\n\\nRun below script in shell #2:\\nfor ((i=1;i\u003e0;i++)) do xfs_io -f /mnt/f2fs/enc/file \\\\\\n-c \\\"pwrite 0 32k\\\" -c \\\"fdatasync\\\"\\n\\nSo, in f2fs_merge_page_bio(), let\u0027s avoid using fio-\u003eencrypted_page after\\ncommit page into internal ipu cache.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/01118321e0c8a5f3ece57d0d377bfc92d83cd210\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/edf7e9040fc52c922db947f9c6c36f07377c52ea\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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