Bug 2348106 (CVE-2022-49147)

Summary: CVE-2022-49147 kernel: block: Fix the maximum minor value is blk_alloc_ext_minor()
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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Description OSIDB Bzimport 2025-02-26 03:17:49 UTC 
In the Linux kernel, the following vulnerability has been resolved:

block: Fix the maximum minor value is blk_alloc_ext_minor()

ida_alloc_range(..., min, max, ...) returns values from min to max,
inclusive.

So, NR_EXT_DEVT is a valid idx returned by blk_alloc_ext_minor().

This is an issue because in device_add_disk(), this value is used in:
   ddev->devt = MKDEV(disk->major, disk->first_minor);
and NR_EXT_DEVT is '(1 << MINORBITS)'.

So, should 'disk->first_minor' be NR_EXT_DEVT, it would overflow.
Comment 1 Avinash Hanwate 2025-02-26 13:40:19 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022608-CVE-2022-49147-7f2f@gregkh/T
Comment 4 Avinash Hanwate 2025-02-26 18:09:42 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022608-CVE-2022-49147-7f2f@gregkh/T