Re: [PATCH v2 02/15] crypto: morus - fix handling chunked inputs

[Ondrej Mosnacek <omosnace@redhat.com>]

On Fri, Feb 1, 2019 at 8:52 AM Eric Biggers <ebiggers@kernel.org> wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> The generic MORUS implementations all fail the improved AEAD tests
> because they produce the wrong result with some data layouts.  The issue
> is that they assume that if the skcipher_walk API gives 'nbytes' not
> aligned to the walksize (a.k.a. walk.stride), then it is the end of the
> data.  In fact, this can happen before the end.  Fix them.
>
> Fixes: 396be41f16fd ("crypto: morus - Add generic MORUS AEAD implementations")
> Cc: <stable@vger.kernel.org> # v4.18+
> Cc: Ondrej Mosnacek <omosnace@redhat.com>
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>


> ---
>  crypto/morus1280.c | 13 +++++++------
>  crypto/morus640.c  | 13 +++++++------
>  2 files changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/crypto/morus1280.c b/crypto/morus1280.c
> index 78ba09db7328c..0747732d5b78a 100644
> --- a/crypto/morus1280.c
> +++ b/crypto/morus1280.c
> @@ -362,18 +362,19 @@ static void crypto_morus1280_process_crypt(struct morus1280_state *state,
>                                            const struct morus1280_ops *ops)
>  {
>         struct skcipher_walk walk;
> -       u8 *dst;
> -       const u8 *src;
>
>         ops->skcipher_walk_init(&walk, req, false);
>
>         while (walk.nbytes) {
> -               src = walk.src.virt.addr;
> -               dst = walk.dst.virt.addr;
> +               unsigned int nbytes = walk.nbytes;
>
> -               ops->crypt_chunk(state, dst, src, walk.nbytes);
> +               if (nbytes < walk.total)
> +                       nbytes = round_down(nbytes, walk.stride);
>
> -               skcipher_walk_done(&walk, 0);
> +               ops->crypt_chunk(state, walk.dst.virt.addr, walk.src.virt.addr,
> +                                nbytes);
> +
> +               skcipher_walk_done(&walk, walk.nbytes - nbytes);
>         }
>  }
>
> diff --git a/crypto/morus640.c b/crypto/morus640.c
> index 5cf530139b271..1617a1eb8be13 100644
> --- a/crypto/morus640.c
> +++ b/crypto/morus640.c
> @@ -361,18 +361,19 @@ static void crypto_morus640_process_crypt(struct morus640_state *state,
>                                           const struct morus640_ops *ops)
>  {
>         struct skcipher_walk walk;
> -       u8 *dst;
> -       const u8 *src;
>
>         ops->skcipher_walk_init(&walk, req, false);
>
>         while (walk.nbytes) {
> -               src = walk.src.virt.addr;
> -               dst = walk.dst.virt.addr;
> +               unsigned int nbytes = walk.nbytes;
>
> -               ops->crypt_chunk(state, dst, src, walk.nbytes);
> +               if (nbytes < walk.total)
> +                       nbytes = round_down(nbytes, walk.stride);
>
> -               skcipher_walk_done(&walk, 0);
> +               ops->crypt_chunk(state, walk.dst.virt.addr, walk.src.virt.addr,
> +                                nbytes);
> +
> +               skcipher_walk_done(&walk, walk.nbytes - nbytes);
>         }
>  }
>
> --
> 2.20.1
>


--
Ondrej Mosnacek <omosnace at redhat dot com>
Associate Software Engineer, Security Technologies
Red Hat, Inc.