Bug 2348524 (CVE-2025-21736)

Summary: CVE-2025-21736 kernel: nilfs2: fix possible int overflows in nilfs_fiemap()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-02-27 03:01:51 UTC 
In the Linux kernel, the following vulnerability has been resolved:

nilfs2: fix possible int overflows in nilfs_fiemap()

Since nilfs_bmap_lookup_contig() in nilfs_fiemap() calculates its result
by being prepared to go through potentially maxblocks == INT_MAX blocks,
the value in n may experience an overflow caused by left shift of blkbits.

While it is extremely unlikely to occur, play it safe and cast right hand
expression to wider type to mitigate the issue.

Found by Linux Verification Center (linuxtesting.org) with static analysis
tool SVACE.
Comment 1 Michal Findra 2025-02-27 14:55:53 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022659-CVE-2025-21736-6d94@gregkh/T