Bug 2347675 (CVE-2022-49210)

Summary: CVE-2022-49210 kernel: MIPS: pgalloc: fix memory leak caused by pgd_free()
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 03:02:48 UTC
In the Linux kernel, the following vulnerability has been resolved:

MIPS: pgalloc: fix memory leak caused by pgd_free()

pgd page is freed by generic implementation pgd_free() since commit
f9cb654cb550 ("asm-generic: pgalloc: provide generic pgd_free()"),
however, there are scenarios that the system uses more than one page as
the pgd table, in such cases the generic implementation pgd_free() won't
be applicable anymore. For example, when PAGE_SIZE_4KB is enabled and
MIPS_VA_BITS_48 is not enabled in a 64bit system, the macro "PGD_ORDER"
will be set as "1", which will cause allocating two pages as the pgd
table. Well, at the same time, the generic implementation pgd_free()
just free one pgd page, which will result in the memory leak.

The memory leak can be easily detected by executing shell command:
"while true; do ls > /dev/null; grep MemFree /proc/meminfo; done"

Comment 1 Mauro Matteo Cascella 2025-02-26 10:15:58 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022619-CVE-2022-49210-6839@gregkh/T