GHSA-5FX7-QFG5-MPMC
Vulnerability from github – Published: 2024-02-27 21:31 – Updated: 2025-01-08 18:30In the Linux kernel, the following vulnerability has been resolved:
ovl: fix leaked dentry
Since commit 6815f479ca90 ("ovl: use only uppermetacopy state in ovl_lookup()"), overlayfs doesn't put temporary dentry when there is a metacopy error, which leads to dentry leaks when shutting down the related superblock:
overlayfs: refusing to follow metacopy origin for (/file0) ... BUG: Dentry (_ptrval_){i=3f33,n=file3} still in use (1) [unmount of overlay overlay] ... WARNING: CPU: 1 PID: 432 at umount_check.cold+0x107/0x14d CPU: 1 PID: 432 Comm: unmount-overlay Not tainted 5.12.0-rc5 #1 ... RIP: 0010:umount_check.cold+0x107/0x14d ... Call Trace: d_walk+0x28c/0x950 ? dentry_lru_isolate+0x2b0/0x2b0 ? __kasan_slab_free+0x12/0x20 do_one_tree+0x33/0x60 shrink_dcache_for_umount+0x78/0x1d0 generic_shutdown_super+0x70/0x440 kill_anon_super+0x3e/0x70 deactivate_locked_super+0xc4/0x160 deactivate_super+0xfa/0x140 cleanup_mnt+0x22e/0x370 __cleanup_mnt+0x1a/0x30 task_work_run+0x139/0x210 do_exit+0xb0c/0x2820 ? __kasan_check_read+0x1d/0x30 ? find_held_lock+0x35/0x160 ? lock_release+0x1b6/0x660 ? mm_update_next_owner+0xa20/0xa20 ? reacquire_held_locks+0x3f0/0x3f0 ? __sanitizer_cov_trace_const_cmp4+0x22/0x30 do_group_exit+0x135/0x380 __do_sys_exit_group.isra.0+0x20/0x20 __x64_sys_exit_group+0x3c/0x50 do_syscall_64+0x45/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae ... VFS: Busy inodes after unmount of overlay. Self-destruct in 5 seconds. Have a nice day...
This fix has been tested with a syzkaller reproducer.
{
"affected": [],
"aliases": [
"CVE-2021-46972"
],
"database_specific": {
"cwe_ids": [
"CWE-401"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-02-27T19:04:07Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\novl: fix leaked dentry\n\nSince commit 6815f479ca90 (\"ovl: use only uppermetacopy state in\novl_lookup()\"), overlayfs doesn\u0027t put temporary dentry when there is a\nmetacopy error, which leads to dentry leaks when shutting down the related\nsuperblock:\n\n overlayfs: refusing to follow metacopy origin for (/file0)\n ...\n BUG: Dentry (____ptrval____){i=3f33,n=file3} still in use (1) [unmount of overlay overlay]\n ...\n WARNING: CPU: 1 PID: 432 at umount_check.cold+0x107/0x14d\n CPU: 1 PID: 432 Comm: unmount-overlay Not tainted 5.12.0-rc5 #1\n ...\n RIP: 0010:umount_check.cold+0x107/0x14d\n ...\n Call Trace:\n d_walk+0x28c/0x950\n ? dentry_lru_isolate+0x2b0/0x2b0\n ? __kasan_slab_free+0x12/0x20\n do_one_tree+0x33/0x60\n shrink_dcache_for_umount+0x78/0x1d0\n generic_shutdown_super+0x70/0x440\n kill_anon_super+0x3e/0x70\n deactivate_locked_super+0xc4/0x160\n deactivate_super+0xfa/0x140\n cleanup_mnt+0x22e/0x370\n __cleanup_mnt+0x1a/0x30\n task_work_run+0x139/0x210\n do_exit+0xb0c/0x2820\n ? __kasan_check_read+0x1d/0x30\n ? find_held_lock+0x35/0x160\n ? lock_release+0x1b6/0x660\n ? mm_update_next_owner+0xa20/0xa20\n ? reacquire_held_locks+0x3f0/0x3f0\n ? __sanitizer_cov_trace_const_cmp4+0x22/0x30\n do_group_exit+0x135/0x380\n __do_sys_exit_group.isra.0+0x20/0x20\n __x64_sys_exit_group+0x3c/0x50\n do_syscall_64+0x45/0x70\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n ...\n VFS: Busy inodes after unmount of overlay. Self-destruct in 5 seconds. Have a nice day...\n\nThis fix has been tested with a syzkaller reproducer.",
"id": "GHSA-5fx7-qfg5-mpmc",
"modified": "2025-01-08T18:30:40Z",
"published": "2024-02-27T21:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-46972"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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