Re: [PATCH v2] crypto: arm64: CE: implement export/import

[Ard Biesheuvel]

On Mon, 24 Feb 2020 at 15:47, Corentin Labbe <clabbe@xxxxxxxxxxxx> wrote:
>
> When an ahash algorithm fallback to another ahash and that fallback is
> shaXXX-CE, doing export/import lead to error like this:
> alg: ahash: sha1-sun8i-ce export() overran state buffer on test vector 0, cfg=\"import/export\"
>
> This is due to the descsize of shaxxx-ce being larger than struct shaxxx_state
> off by an u32.
> For fixing this, let's implement export/import which rip the finalize
> variant instead of using generic export/import.
>
> Fixes: 6ba6c74dfc6b ("arm64/crypto: SHA-224/SHA-256 using ARMv8 Crypto Extensions")
> Fixes: 2c98833a42cd ("arm64/crypto: SHA-1 using ARMv8 Crypto Extensions")
>
> Signed-off-by: Corentin Labbe <clabbe@xxxxxxxxxxxx>

Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx>

> ---
> Changes since v1:
> - memcpy directly &sctx->sst instead of sctx. As suggested by Eric Biggers
>
>  arch/arm64/crypto/sha1-ce-glue.c | 20 ++++++++++++++++++++
>  arch/arm64/crypto/sha2-ce-glue.c | 23 +++++++++++++++++++++++
>  2 files changed, 43 insertions(+)
>
> diff --git a/arch/arm64/crypto/sha1-ce-glue.c b/arch/arm64/crypto/sha1-ce-glue.c
> index 63c875d3314b..565ef604ca04 100644
> --- a/arch/arm64/crypto/sha1-ce-glue.c
> +++ b/arch/arm64/crypto/sha1-ce-glue.c
> @@ -91,12 +91,32 @@ static int sha1_ce_final(struct shash_desc *desc, u8 *out)
>         return sha1_base_finish(desc, out);
>  }
>
> +static int sha1_ce_export(struct shash_desc *desc, void *out)
> +{
> +       struct sha1_ce_state *sctx = shash_desc_ctx(desc);
> +
> +       memcpy(out, &sctx->sst, sizeof(struct sha1_state));
> +       return 0;
> +}
> +
> +static int sha1_ce_import(struct shash_desc *desc, const void *in)
> +{
> +       struct sha1_ce_state *sctx = shash_desc_ctx(desc);
> +
> +       memcpy(&sctx->sst, in, sizeof(struct sha1_state));
> +       sctx->finalize = 0;
> +       return 0;
> +}
> +
>  static struct shash_alg alg = {
>         .init                   = sha1_base_init,
>         .update                 = sha1_ce_update,
>         .final                  = sha1_ce_final,
>         .finup                  = sha1_ce_finup,
> +       .import                 = sha1_ce_import,
> +       .export                 = sha1_ce_export,
>         .descsize               = sizeof(struct sha1_ce_state),
> +       .statesize              = sizeof(struct sha1_state),
>         .digestsize             = SHA1_DIGEST_SIZE,
>         .base                   = {
>                 .cra_name               = "sha1",
> diff --git a/arch/arm64/crypto/sha2-ce-glue.c b/arch/arm64/crypto/sha2-ce-glue.c
> index a8e67bafba3d..9450d19b9e6e 100644
> --- a/arch/arm64/crypto/sha2-ce-glue.c
> +++ b/arch/arm64/crypto/sha2-ce-glue.c
> @@ -109,12 +109,32 @@ static int sha256_ce_final(struct shash_desc *desc, u8 *out)
>         return sha256_base_finish(desc, out);
>  }
>
> +static int sha256_ce_export(struct shash_desc *desc, void *out)
> +{
> +       struct sha256_ce_state *sctx = shash_desc_ctx(desc);
> +
> +       memcpy(out, &sctx->sst, sizeof(struct sha256_state));
> +       return 0;
> +}
> +
> +static int sha256_ce_import(struct shash_desc *desc, const void *in)
> +{
> +       struct sha256_ce_state *sctx = shash_desc_ctx(desc);
> +
> +       memcpy(&sctx->sst, in, sizeof(struct sha256_state));
> +       sctx->finalize = 0;
> +       return 0;
> +}
> +
>  static struct shash_alg algs[] = { {
>         .init                   = sha224_base_init,
>         .update                 = sha256_ce_update,
>         .final                  = sha256_ce_final,
>         .finup                  = sha256_ce_finup,
> +       .export                 = sha256_ce_export,
> +       .import                 = sha256_ce_import,
>         .descsize               = sizeof(struct sha256_ce_state),
> +       .statesize              = sizeof(struct sha256_state),
>         .digestsize             = SHA224_DIGEST_SIZE,
>         .base                   = {
>                 .cra_name               = "sha224",
> @@ -128,7 +148,10 @@ static struct shash_alg algs[] = { {
>         .update                 = sha256_ce_update,
>         .final                  = sha256_ce_final,
>         .finup                  = sha256_ce_finup,
> +       .export                 = sha256_ce_export,
> +       .import                 = sha256_ce_import,
>         .descsize               = sizeof(struct sha256_ce_state),
> +       .statesize              = sizeof(struct sha256_state),
>         .digestsize             = SHA256_DIGEST_SIZE,
>         .base                   = {
>                 .cra_name               = "sha256",
> --
> 2.24.1
>