Re: [PATCH] KVM: SVM: Use kzalloc for sev ioctl interfaces to prevent kernel memory leak.

[Borislav Petkov]

On Thu, May 12, 2022 at 08:23:28PM +0000, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@xxxxxxx>
> 
> For some sev ioctl interfaces, the length parameter that is passed maybe
> less than or equal to SEV_FW_BLOB_MAX_SIZE, but larger than the data
> that PSP firmware returns. In this case, kmalloc will allocate memory
> that is the size of the input rather than the size of the data.
> Since PSP firmware doesn't fully overwrite the allocated buffer, these
> sev ioctl interface may return uninitialized kernel slab memory.
> 
> Reported-by: Andy Nguyen <theflow@xxxxxxxxxx>
> Suggested-by: David Rientjes <rientjes@xxxxxxxxxx>
> Suggested-by: Peter Gonda <pgonda@xxxxxxxxxx>
> Cc: kvm@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>

This looks like it needs one (or more) Fixes: tags pointing to the
patch(es) adding those kmalloc calls...

And then Cc: <stable@xxxxxxxxxxxxxxx> too.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette