APPLIED: [SRU][M][PATCH 0/1] CVE-2024-26710

[Roxana Nicolescu]

On 19/04/2024 22:49, Bethany Jamison wrote:
> [Impact]
>
>   In the Linux kernel, the following vulnerability has been resolved:
>
>   powerpc/kasan: Limit KASAN thread size increase to 32KB
>
>   KASAN is seen to increase stack usage, to the point that it was reported
>   to lead to stack overflow on some 32-bit machines (see link).
>
>   To avoid overflows the stack size was doubled for KASAN builds in
>   commit 3e8635fb2e07 ("powerpc/kasan: Force thread size increase with
>   KASAN").
>
>   However with a 32KB stack size to begin with, the doubling leads to a
>   64KB stack, which causes build errors:
>     arch/powerpc/kernel/switch.S:249: Error: operand out of range
>   (0x000000000000fe50 is not between 0xffffffffffff8000 and
>   0x0000000000007fff)
>
>   Although the asm could be reworked, in practice a 32KB stack seems
>   sufficient even for KASAN builds - the additional usage seems to be in
>   the 2-3KB range for a 64-bit KASAN build.
>
>   So only increase the stack for KASAN if the stack size is < 32KB.
>
> [Fix]
>
> Mantic:	Clean cherry-pick from linux-6.6.y
> Jammy:	not-affected
> Focal:	not-affected
> Bionic:	not-affected
> Xenial:	not-affected
> Trusty:	not-affected
>
> [Test Case]
>
> Compile and boot tested.
>
> [Where problems could occur]
>
> This fix affects those who use KASAN on PowerPC, an issue with this
> fix would be visable to the user via a system crash.
>
> Michael Ellerman (1):
>    powerpc/kasan: Limit KASAN thread size increase to 32KB
>
>   arch/powerpc/include/asm/thread_info.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
It was applied already from upstream. I included the CVE no in the 
commit message.