On Sun, 05 Nov 2023 23:29:36 +0300, Sergey Shtylyov wrote:
> In persistent_ram_init_ecc(), on 64-bit arches DIV_ROUND_UP() will return
> 64-bit value since persistent_ram_zone::buffer_size has type size_t which
> is derived from the 64-bit *unsigned long*, while the ecc_blocks variable
> this value gets assigned to has (always 32-bit) *int* type. Even if that
> value fits into *int* type, an overflow is still possible when calculating
> the size_t typed ecc_total variable further below since there's no cast to
> any 64-bit type before multiplication. Declaring the ecc_blocks variable
> as *unsigned long* should fix this mess...
>
> [...]
I changed this from unsigned long to size_t, which will do the same thing.
Applied to for-linus/pstore, thanks!
[1/1] pstore: ram_core: fix possible overflow in persistent_ram_init_ecc()
https://git.kernel.org/kees/c/c92116e01d32
Take care,
--
Kees Cook
