Bug 2334418 (CVE-2024-53234)

Summary: CVE-2024-53234 kernel: erofs: handle NONHEAD !delta[1] lclusters gracefully
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2024-12-27 14:05:42 UTC 
In the Linux kernel, the following vulnerability has been resolved:

erofs: handle NONHEAD !delta[1] lclusters gracefully

syzbot reported a WARNING in iomap_iter_done:
 iomap_fiemap+0x73b/0x9b0 fs/iomap/fiemap.c:80
 ioctl_fiemap fs/ioctl.c:220 [inline]

Generally, NONHEAD lclusters won't have delta[1]==0, except for crafted
images and filesystems created by pre-1.0 mkfs versions.

Previously, it would immediately bail out if delta[1]==0, which led to
inadequate decompressed lengths (thus FIEMAP is impacted).  Treat it as
delta[1]=1 to work around these legacy mkfs versions.

`lclusterbits > 14` is illegal for compact indexes, error out too.
Comment 1 Avinash Hanwate 2024-12-28 10:02:09 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024122738-CVE-2024-53234-4ee6@gregkh/T