• Ard Biesheuvel's avatar
    crypto: mxs-dcp - permit asynchronous skcipher as fallback · c9598d4e
    Ard Biesheuvel authored
    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: default avatarArd Biesheuvel <ardb@kernel.org>
    Reviewed-by: default avatarHoria Geantă <horia.geanta@nxp.com>
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    c9598d4e
mxs-dcp.c 29 KB