| Summary: |
VUL-0: CVE-2021-46972: kernel: ovl: dentry leak in ovl_lookup() |
| Product: |
[Novell Products] SUSE Security Incidents
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Reporter: |
SMASH SMASH <smash_bz> |
| Component: |
Incidents | Assignee: |
Kernel Bugs <kernel-bugs> |
| Status: |
RESOLVED
FIXED
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QA Contact: |
Security Team bot <security-team> |
| Severity: |
Normal
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| Priority: |
P5 - None
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CC: |
carlos.lopez
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| Version: |
unspecified | |
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| Target Milestone: |
--- | |
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| Hardware: |
Other | |
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| OS: |
Other | |
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| URL: |
https://smash.suse.de/issue/395378/
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| Whiteboard: |
CVSSv3.1:SUSE:CVE-2021-46972:5.5:(AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) |
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Found By:
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Security Response Team
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Services Priority:
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Business Priority:
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Blocker:
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---
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Marketing QA Status:
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IT Deployment:
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In 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. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-46972 https://www.cve.org/CVERecord?id=CVE-2021-46972 https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95 https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94 https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8 https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 https://bugzilla.redhat.com/show_bug.cgi?id=2266831