Bug 2324864 (CVE-2024-50230)

Summary: CVE-2024-50230 kernel: nilfs2: fix kernel bug due to missing clearing of checked flag
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Bug Depends On: 2325085    
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Description OSIDB Bzimport 2024-11-09 11:01:59 UTC 
In the Linux kernel, the following vulnerability has been resolved:

nilfs2: fix kernel bug due to missing clearing of checked flag

Syzbot reported that in directory operations after nilfs2 detects
filesystem corruption and degrades to read-only,
__block_write_begin_int(), which is called to prepare block writes, may
fail the BUG_ON check for accesses exceeding the folio/page size,
triggering a kernel bug.

This was found to be because the "checked" flag of a page/folio was not
cleared when it was discarded by nilfs2's own routine, which causes the
sanity check of directory entries to be skipped when the directory
page/folio is reloaded.  So, fix that.

This was necessary when the use of nilfs2's own page discard routine was
applied to more than just metadata files.
Comment 1 Avinash Hanwate 2024-11-11 04:45:31 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024110929-CVE-2024-50230-0b5e@gregkh/T