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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Sat, 22 Aug 2020 15:04:10 +0200
Message-ID: <CAMj1kXFTCtRz99BzDsbmb8cPbMEM8Bi73nfp-ru4Zr2SECB9CA@mail.gmail.com>
Subject: Re: [PATCH] crypto: qat - aead cipher length should be block multiple
To:     Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        qat-linux@intel.com,
        Dominik Przychodni <dominik.przychodni@intel.com>
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On Sat, 22 Aug 2020 at 09:29, Giovanni Cabiddu
<giovanni.cabiddu@intel.com> wrote:
>
> From: Dominik Przychodni <dominik.przychodni@intel.com>
>
> Include an additional check on the cipher length to prevent undefined
> behaviour from occurring upon submitting requests which are not a
> multiple of AES_BLOCK_SIZE.
>
> Fixes: d370cec32194 ("crypto: qat - Intel(R) QAT crypto interface")
> Signed-off-by: Dominik Przychodni <dominik.przychodni@intel.com>
> Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>

I only looked at the patch, and not at the entire file, but could you
explain which AES based AEAD implementations require the input length
to be a multiple of the block size? CCM and GCM are both CTR based,
and so any input length should be supported for at least those modes.


> ---
>  drivers/crypto/qat/qat_common/qat_algs.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/crypto/qat/qat_common/qat_algs.c b/drivers/crypto/qat/qat_common/qat_algs.c
> index 72753b84dc95..d552dbcfe0a0 100644
> --- a/drivers/crypto/qat/qat_common/qat_algs.c
> +++ b/drivers/crypto/qat/qat_common/qat_algs.c
> @@ -828,6 +828,11 @@ static int qat_alg_aead_dec(struct aead_request *areq)
>         struct icp_qat_fw_la_bulk_req *msg;
>         int digst_size = crypto_aead_authsize(aead_tfm);
>         int ret, ctr = 0;
> +       u32 cipher_len;
> +
> +       cipher_len = areq->cryptlen - digst_size;
> +       if (cipher_len % AES_BLOCK_SIZE != 0)
> +               return -EINVAL;
>
>         ret = qat_alg_sgl_to_bufl(ctx->inst, areq->src, areq->dst, qat_req);
>         if (unlikely(ret))
> @@ -842,7 +847,7 @@ static int qat_alg_aead_dec(struct aead_request *areq)
>         qat_req->req.comn_mid.src_data_addr = qat_req->buf.blp;
>         qat_req->req.comn_mid.dest_data_addr = qat_req->buf.bloutp;
>         cipher_param = (void *)&qat_req->req.serv_specif_rqpars;
> -       cipher_param->cipher_length = areq->cryptlen - digst_size;
> +       cipher_param->cipher_length = cipher_len;
>         cipher_param->cipher_offset = areq->assoclen;
>         memcpy(cipher_param->u.cipher_IV_array, areq->iv, AES_BLOCK_SIZE);
>         auth_param = (void *)((u8 *)cipher_param + sizeof(*cipher_param));
> @@ -871,6 +876,9 @@ static int qat_alg_aead_enc(struct aead_request *areq)
>         u8 *iv = areq->iv;
>         int ret, ctr = 0;
>
> +       if (areq->cryptlen % AES_BLOCK_SIZE != 0)
> +               return -EINVAL;
> +
>         ret = qat_alg_sgl_to_bufl(ctx->inst, areq->src, areq->dst, qat_req);
>         if (unlikely(ret))
>                 return ret;
> --
> 2.26.2
>