ghsa-595v-ghj9-chj5
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix use-after-free when attempting to join an aborted transaction
When we are trying to join the current transaction and if it's aborted, we read its 'aborted' field after unlocking fs_info->trans_lock and without holding any extra reference count on it. This means that a concurrent task that is aborting the transaction may free the transaction before we read its 'aborted' field, leading to a use-after-free.
Fix this by reading the 'aborted' field while holding fs_info->trans_lock since any freeing task must first acquire that lock and set fs_info->running_transaction to NULL before freeing the transaction.
This was reported by syzbot and Dmitry with the following stack traces from KASAN:
================================================================== BUG: KASAN: slab-use-after-free in join_transaction+0xd9b/0xda0 fs/btrfs/transaction.c:278 Read of size 4 at addr ffff888011839024 by task kworker/u4:9/1128
CPU: 0 UID: 0 PID: 1128 Comm: kworker/u4:9 Not tainted 6.13.0-rc7-syzkaller-00019-gc45323b7560e #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: events_unbound btrfs_async_reclaim_data_space Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 join_transaction+0xd9b/0xda0 fs/btrfs/transaction.c:278 start_transaction+0xaf8/0x1670 fs/btrfs/transaction.c:697 flush_space+0x448/0xcf0 fs/btrfs/space-info.c:803 btrfs_async_reclaim_data_space+0x159/0x510 fs/btrfs/space-info.c:1321 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+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Allocated by task 5315: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4329 kmalloc_noprof include/linux/slab.h:901 [inline] join_transaction+0x144/0xda0 fs/btrfs/transaction.c:308 start_transaction+0xaf8/0x1670 fs/btrfs/transaction.c:697 btrfs_create_common+0x1b2/0x2e0 fs/btrfs/inode.c:6572 lookup_open fs/namei.c:3649 [inline] open_last_lookups fs/namei.c:3748 [inline] path_openat+0x1c03/0x3590 fs/namei.c:3984 do_filp_open+0x27f/0x4e0 fs/namei.c:4014 do_sys_openat2+0x13e/0x1d0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_creat fs/open.c:1495 [inline] __se_sys_creat fs/open.c:1489 [inline] __x64_sys_creat+0x123/0x170 fs/open.c:1489 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 5336: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4613 [inline] kfree+0x196/0x430 mm/slub.c:4761 cleanup_transaction fs/btrfs/transaction.c:2063 [inline] btrfs_commit_transaction+0x2c97/0x3720 fs/btrfs/transaction.c:2598 insert_balance_item+0x1284/0x20b0 fs/btrfs/volumes.c:3757 btrfs_balance+0x992/ ---truncated---
{
"affected": [],
"aliases": [
"CVE-2025-21753"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-27T03:15:15Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix use-after-free when attempting to join an aborted transaction\n\nWhen we are trying to join the current transaction and if it\u0027s aborted,\nwe read its \u0027aborted\u0027 field after unlocking fs_info-\u003etrans_lock and\nwithout holding any extra reference count on it. This means that a\nconcurrent task that is aborting the transaction may free the transaction\nbefore we read its \u0027aborted\u0027 field, leading to a use-after-free.\n\nFix this by reading the \u0027aborted\u0027 field while holding fs_info-\u003etrans_lock\nsince any freeing task must first acquire that lock and set\nfs_info-\u003erunning_transaction to NULL before freeing the transaction.\n\nThis was reported by syzbot and Dmitry with the following stack traces\nfrom KASAN:\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in join_transaction+0xd9b/0xda0 fs/btrfs/transaction.c:278\n Read of size 4 at addr ffff888011839024 by task kworker/u4:9/1128\n\n CPU: 0 UID: 0 PID: 1128 Comm: kworker/u4:9 Not tainted 6.13.0-rc7-syzkaller-00019-gc45323b7560e #0\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\n Workqueue: events_unbound btrfs_async_reclaim_data_space\n Call Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:489\n kasan_report+0x143/0x180 mm/kasan/report.c:602\n join_transaction+0xd9b/0xda0 fs/btrfs/transaction.c:278\n start_transaction+0xaf8/0x1670 fs/btrfs/transaction.c:697\n flush_space+0x448/0xcf0 fs/btrfs/space-info.c:803\n btrfs_async_reclaim_data_space+0x159/0x510 fs/btrfs/space-info.c:1321\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+0x2f0/0x390 kernel/kthread.c:389\n ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n \u003c/TASK\u003e\n\n Allocated by task 5315:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n poison_kmalloc_redzone mm/kasan/common.c:377 [inline]\n __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394\n kasan_kmalloc include/linux/kasan.h:260 [inline]\n __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4329\n kmalloc_noprof include/linux/slab.h:901 [inline]\n join_transaction+0x144/0xda0 fs/btrfs/transaction.c:308\n start_transaction+0xaf8/0x1670 fs/btrfs/transaction.c:697\n btrfs_create_common+0x1b2/0x2e0 fs/btrfs/inode.c:6572\n lookup_open fs/namei.c:3649 [inline]\n open_last_lookups fs/namei.c:3748 [inline]\n path_openat+0x1c03/0x3590 fs/namei.c:3984\n do_filp_open+0x27f/0x4e0 fs/namei.c:4014\n do_sys_openat2+0x13e/0x1d0 fs/open.c:1402\n do_sys_open fs/open.c:1417 [inline]\n __do_sys_creat fs/open.c:1495 [inline]\n __se_sys_creat fs/open.c:1489 [inline]\n __x64_sys_creat+0x123/0x170 fs/open.c:1489\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n Freed by task 5336:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582\n poison_slab_object mm/kasan/common.c:247 [inline]\n __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264\n kasan_slab_free include/linux/kasan.h:233 [inline]\n slab_free_hook mm/slub.c:2353 [inline]\n slab_free mm/slub.c:4613 [inline]\n kfree+0x196/0x430 mm/slub.c:4761\n cleanup_transaction fs/btrfs/transaction.c:2063 [inline]\n btrfs_commit_transaction+0x2c97/0x3720 fs/btrfs/transaction.c:2598\n insert_balance_item+0x1284/0x20b0 fs/btrfs/volumes.c:3757\n btrfs_balance+0x992/\n---truncated---",
"id": "GHSA-595v-ghj9-chj5",
"modified": "2025-03-13T15:32:50Z",
"published": "2025-02-27T03:34:04Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21753"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6ba4663ada6c6315af23a6669d386146634808ec"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7e954b6bb95d67ae4d1a20e9cfd83c182cf929bc"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/86d71a026a7f63da905db9add845c8ee88801eca"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8f5cff471039caa2b088060c074c2bf2081bcb01"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c7a53757717e68af94a56929d57f1e6daff220ec"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ce628048390dad80320d5a1f74de6ca1e1be91e7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cee55b1219568c80bf0d5dc55066e4a859baf753"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e2f0943cf37305dbdeaf9846e3c941451bcdef63"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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