On Tue, 2024-07-30 at 17:46 +0200, Greg Kroah-Hartman wrote:
> 6.10-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
>
> commit d9592025000b3cf26c742f3505da7b83aedc26d5 upstream.
>
> Yves-Alexis Perez reported commit 4ef9ad19e176 ("mm: huge_memory: don't
> force huge page alignment on 32 bit") didn't work for x86_32 [1]. It is
> because x86_32 uses CONFIG_X86_32 instead of CONFIG_32BIT.
>
> !CONFIG_64BIT should cover all 32 bit machines.
>
> [1] https://lore.kernel.org/linux-mm/CAHbLzkr1LwH3pcTgM+aGQ31ip2bKqiqEQ8=FQB+t2c3dhNKNHA@xxxxxxxxxxxxxx/
>
> Link: https://lkml.kernel.org/r/20240712155855.1130330-1-yang@xxxxxxxxxxxxxxxxxxxxxx
> Fixes: 4ef9ad19e176 ("mm: huge_memory: don't force huge page alignment on 32 bit")
[...]
The original breakage actually occurred in 5.18 with this commit:
commit 1854bc6e2420472676c5c90d3d6b15f6cd640e40
Author: William Kucharski <william.kucharski@xxxxxxxxxx>
Date: Sun Sep 22 08:43:15 2019 -0400
mm/readahead: Align file mappings for non-DAX
The previous fix referred to above (commit 4ef9ad19e176) was already
backported to 6.1 and 6.7, and CVE-2024-26621 was assigned to the bug.
This new fix also needs to be applied to 6.1. *Both* fixes need to be
applied to 6.6 since the previous fix missed this branch.
I believe a new CVE ID also needs to be assigned to cover the
architectures missed in the previous fix. So far as I can see, the
only architectures supporting huge pages on 32-bit CPUs (as of
6.11-rc1) are arc, arm, mips, and x86. Of those only mips defines
CONFIG_32BIT in 32-bit configurations, and was covered by the previous
fix. The other three are covered by the new fix.
To summarise:
CVE-2024-26621:
- covers 64-bit compat and mips32 native
- fixed by commit 4ef9ad19e176
- fix is needed in 6.6
CVE ID to be assigned:
- covers arc, arm, and x86_32 native
- fixed by commit d9592025000b
- fix is needed in 6.1 and 6.6
Ben.
--
Ben Hutchings
To err is human; to really foul things up requires a computer.
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