In the Linux kernel, the following vulnerability has been resolved:
crypto: ccp – Check for page allocation failure correctly in TIO
Sashiko notes:
> if __snp_alloc_firmware_pages() returns NULL under memory pressure, is it
> safe to pass it directly to page_address()?
>
> On architectures without HASHED_PAGE_VIRTUAL, page_address(NULL) might
> compute a deterministic but invalid, non-zero virtual address. The
> subsequent if (tio_status) check would then evaluate to true, and
> sev_tsm_init_locked() would dereference the invalid pointer.
Indeed, page_address(NULL) will return non-NULL garbage here. Fix this by
checking the page allocation itself for NULL, not the resulting virtual
address.
