Re: [PATCH v3 09/13] crypto: mxs-dcp - permit asynchronous skcipher as fallback

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 6/30/2020 3:20 PM, Ard Biesheuvel wrote:
> Even though the mxs-dcp driver implements asynchronous versions of
> ecb(aes) and cbc(aes), the fallbacks it allocates are required to be
> synchronous. Given that SIMD based software implementations are usually
> asynchronous as well, even though they rarely complete asynchronously
> (this typically only happens in cases where the request was made from
> softirq context, while SIMD was already in use in the task context that
> it interrupted), these implementations are disregarded, and either the
> generic C version or another table based version implemented in assembler
> is selected instead.
> 
> Since falling back to synchronous AES is not only a performance issue, but
> potentially a security issue as well (due to the fact that table based AES
> is not time invariant), let's fix this, by allocating an ordinary skcipher
> as the fallback, and invoke it with the completion routine that was given
> to the outer request.
> 
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Reviewed-by: Horia Geantă <horia.geanta@xxxxxxx>

Thanks,
Horia



[Index of Archives]     [Kernel]     [Gnu Classpath]     [Gnu Crypto]     [DM Crypt]     [Netfilter]     [Bugtraq]

  Powered by Linux