ghsa-h5r3-g6g9-3w6p
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
ext4: block range must be validated before use in ext4_mb_clear_bb()
Block range to free is validated in ext4_free_blocks() using ext4_inode_block_valid() and then it's passed to ext4_mb_clear_bb(). However in some situations on bigalloc file system the range might be adjusted after the validation in ext4_free_blocks() which can lead to troubles on corrupted file systems such as one found by syzkaller that resulted in the following BUG
kernel BUG at fs/ext4/ext4.h:3319! PREEMPT SMP NOPTI CPU: 28 PID: 4243 Comm: repro Kdump: loaded Not tainted 5.19.0-rc6+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014 RIP: 0010:ext4_free_blocks+0x95e/0xa90 Call Trace: ? lock_timer_base+0x61/0x80 ? __es_remove_extent+0x5a/0x760 ? __mod_timer+0x256/0x380 ? ext4_ind_truncate_ensure_credits+0x90/0x220 ext4_clear_blocks+0x107/0x1b0 ext4_free_data+0x15b/0x170 ext4_ind_truncate+0x214/0x2c0 ? _raw_spin_unlock+0x15/0x30 ? ext4_discard_preallocations+0x15a/0x410 ? ext4_journal_check_start+0xe/0x90 ? __ext4_journal_start_sb+0x2f/0x110 ext4_truncate+0x1b5/0x460 ? __ext4_journal_start_sb+0x2f/0x110 ext4_evict_inode+0x2b4/0x6f0 evict+0xd0/0x1d0 ext4_enable_quotas+0x11f/0x1f0 ext4_orphan_cleanup+0x3de/0x430 ? proc_create_seq_private+0x43/0x50 ext4_fill_super+0x295f/0x3ae0 ? snprintf+0x39/0x40 ? sget_fc+0x19c/0x330 ? ext4_reconfigure+0x850/0x850 get_tree_bdev+0x16d/0x260 vfs_get_tree+0x25/0xb0 path_mount+0x431/0xa70 __x64_sys_mount+0xe2/0x120 do_syscall_64+0x5b/0x80 ? do_user_addr_fault+0x1e2/0x670 ? exc_page_fault+0x70/0x170 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fdf4e512ace
Fix it by making sure that the block range is properly validated before used every time it changes in ext4_free_blocks() or ext4_mb_clear_bb().
{
"affected": [],
"aliases": [
"CVE-2022-50021"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-06-18T11:15:30Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: block range must be validated before use in ext4_mb_clear_bb()\n\nBlock range to free is validated in ext4_free_blocks() using\next4_inode_block_valid() and then it\u0027s passed to ext4_mb_clear_bb().\nHowever in some situations on bigalloc file system the range might be\nadjusted after the validation in ext4_free_blocks() which can lead to\ntroubles on corrupted file systems such as one found by syzkaller that\nresulted in the following BUG\n\nkernel BUG at fs/ext4/ext4.h:3319!\nPREEMPT SMP NOPTI\nCPU: 28 PID: 4243 Comm: repro Kdump: loaded Not tainted 5.19.0-rc6+ #1\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014\nRIP: 0010:ext4_free_blocks+0x95e/0xa90\nCall Trace:\n \u003cTASK\u003e\n ? lock_timer_base+0x61/0x80\n ? __es_remove_extent+0x5a/0x760\n ? __mod_timer+0x256/0x380\n ? ext4_ind_truncate_ensure_credits+0x90/0x220\n ext4_clear_blocks+0x107/0x1b0\n ext4_free_data+0x15b/0x170\n ext4_ind_truncate+0x214/0x2c0\n ? _raw_spin_unlock+0x15/0x30\n ? ext4_discard_preallocations+0x15a/0x410\n ? ext4_journal_check_start+0xe/0x90\n ? __ext4_journal_start_sb+0x2f/0x110\n ext4_truncate+0x1b5/0x460\n ? __ext4_journal_start_sb+0x2f/0x110\n ext4_evict_inode+0x2b4/0x6f0\n evict+0xd0/0x1d0\n ext4_enable_quotas+0x11f/0x1f0\n ext4_orphan_cleanup+0x3de/0x430\n ? proc_create_seq_private+0x43/0x50\n ext4_fill_super+0x295f/0x3ae0\n ? snprintf+0x39/0x40\n ? sget_fc+0x19c/0x330\n ? ext4_reconfigure+0x850/0x850\n get_tree_bdev+0x16d/0x260\n vfs_get_tree+0x25/0xb0\n path_mount+0x431/0xa70\n __x64_sys_mount+0xe2/0x120\n do_syscall_64+0x5b/0x80\n ? do_user_addr_fault+0x1e2/0x670\n ? exc_page_fault+0x70/0x170\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\nRIP: 0033:0x7fdf4e512ace\n\nFix it by making sure that the block range is properly validated before\nused every time it changes in ext4_free_blocks() or ext4_mb_clear_bb().",
"id": "GHSA-h5r3-g6g9-3w6p",
"modified": "2025-06-18T12:30:42Z",
"published": "2025-06-18T12:30:42Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50021"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/560a2744cbbf03cac65a6394f9b0d99aa437c867"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7550aade978371ac582f6d43b14c4cb89ca54463"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a2522041d248a8c969cbbc97e1fc2cd8b4de120d"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.