RE: [PATCH] crypto: mediatek - Fix endianness bugs and sparse warnings

["Van Leeuwen, Pascal" <pvanleeuwen@rambus.com>]

> -----Original Message-----
> From: linux-crypto-owner@vger.kernel.org <linux-crypto-owner@vger.kernel.org> On Behalf Of Herbert Xu
> Sent: Friday, August 21, 2020 9:52 AM
> To: Ryder Lee <ryder.lee@mediatek.com>; Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
> Subject: [PATCH] crypto: mediatek - Fix endianness bugs and sparse warnings
>
> <<< External Email >>>
> This patch squashes all the sparse warnings in mediatek, some of
> which appear to be genuine bugs.  In particular, previously on
> BE the keys and IVs all get 32-bit swabbed which can't be right
> because they don't get swabbed on LE.  I presume LE is the one
> that actually works.
>
> Another funky thing is that the GHASH key gets swabbed on LE.
> This makes no sense but I'm presuming someone actually tested
> this on LE so I'm preserving the swabbing.  Someone needs to
> test this though as it is entirely possible that GCM is the
> only thing that worked on BE but not LE.
>
The byte swapping within 32 bit words of the GHASH is accurate. Agree that the byte ordering
of this hardware is not entirely consistent. Legacy that I have to live with on a daily basis :-)

Unfortunately, I cannot test your changes as I do not have access to the actual hardware.
Superficially, it looks good. Although I doubt the driver will ever be used in a BE context ...

> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
>
> diff --git a/drivers/crypto/mediatek/mtk-aes.c b/drivers/crypto/mediatek/mtk-aes.c
> index 4ad3571ab6af..7323066724c3 100644
> --- a/drivers/crypto/mediatek/mtk-aes.c
> +++ b/drivers/crypto/mediatek/mtk-aes.c
> @@ -126,7 +126,7 @@ struct mtk_aes_ctx {
>  struct mtk_aes_ctr_ctx {
>  struct mtk_aes_base_ctx base;
>
> -u32iv[AES_BLOCK_SIZE / sizeof(u32)];
> +__be32iv[AES_BLOCK_SIZE / sizeof(u32)];
>  size_t offset;
>  struct scatterlist src[2];
>  struct scatterlist dst[2];
> @@ -242,22 +242,6 @@ static inline void mtk_aes_restore_sg(const struct mtk_aes_dma *dma)
>  sg->length += dma->remainder;
>  }
>
> -static inline void mtk_aes_write_state_le(__le32 *dst, const u32 *src, u32 size)
> -{
> -int i;
> -
> -for (i = 0; i < SIZE_IN_WORDS(size); i++)
> -dst[i] = cpu_to_le32(src[i]);
> -}
> -
> -static inline void mtk_aes_write_state_be(__be32 *dst, const u32 *src, u32 size)
> -{
> -int i;
> -
> -for (i = 0; i < SIZE_IN_WORDS(size); i++)
> -dst[i] = cpu_to_be32(src[i]);
> -}
> -
>  static inline int mtk_aes_complete(struct mtk_cryp *cryp,
>     struct mtk_aes_rec *aes,
>     int err)
> @@ -321,7 +305,7 @@ static int mtk_aes_xmit(struct mtk_cryp *cryp, struct mtk_aes_rec *aes)
>
>  /* Prepare enough space for authenticated tag */
>  if (aes->flags & AES_FLAGS_GCM)
> -res->hdr += AES_BLOCK_SIZE;
> +le32_add_cpu(&res->hdr, AES_BLOCK_SIZE);
>
>  /*
>   * Make sure that all changes to the DMA ring are done before we
> @@ -449,10 +433,10 @@ static void mtk_aes_info_init(struct mtk_cryp *cryp, struct mtk_aes_rec *aes,
>  return;
>  }
>
> -mtk_aes_write_state_le(info->state + ctx->keylen, (void *)req->iv,
> -       AES_BLOCK_SIZE);
> +memcpy(info->state + ctx->keylen, req->iv, AES_BLOCK_SIZE);
>  ctr:
> -info->tfm[0] += AES_TFM_SIZE(SIZE_IN_WORDS(AES_BLOCK_SIZE));
> +le32_add_cpu(&info->tfm[0],
> +     le32_to_cpu(AES_TFM_SIZE(SIZE_IN_WORDS(AES_BLOCK_SIZE))));
>  info->tfm[1] |= AES_TFM_FULL_IV;
>  info->cmd[cnt++] = AES_CMD2;
>  ecb:
> @@ -601,8 +585,7 @@ static int mtk_aes_ctr_transfer(struct mtk_cryp *cryp, struct mtk_aes_rec *aes)
>         scatterwalk_ffwd(cctx->dst, req->dst, cctx->offset));
>
>  /* Write IVs into transform state buffer. */
> -mtk_aes_write_state_le(ctx->info.state + ctx->keylen, cctx->iv,
> -       AES_BLOCK_SIZE);
> +memcpy(ctx->info.state + ctx->keylen, cctx->iv, AES_BLOCK_SIZE);
>
>  if (unlikely(fragmented)) {
>  /*
> @@ -654,7 +637,7 @@ static int mtk_aes_setkey(struct crypto_skcipher *tfm,
>  }
>
>  ctx->keylen = SIZE_IN_WORDS(keylen);
> -mtk_aes_write_state_le(ctx->key, (const u32 *)key, keylen);
> +memcpy(ctx->key, key, keylen);
>
>  return 0;
>  }
> @@ -848,7 +831,7 @@ mtk_aes_gcm_ctx_cast(struct mtk_aes_base_ctx *ctx)
>  static int mtk_aes_gcm_tag_verify(struct mtk_cryp *cryp,
>    struct mtk_aes_rec *aes)
>  {
> -u32 status = cryp->ring[aes->id]->res_prev->ct;
> +__le32 status = cryp->ring[aes->id]->res_prev->ct;
>
>  return mtk_aes_complete(cryp, aes, (status & AES_AUTH_TAG_ERR) ?
>  -EBADMSG : 0);
> @@ -866,7 +849,7 @@ static void mtk_aes_gcm_info_init(struct mtk_cryp *cryp,
>  u32 ivsize = crypto_aead_ivsize(crypto_aead_reqtfm(req));
>  u32 cnt = 0;
>
> -ctx->ct_hdr = AES_CT_CTRL_HDR | len;
> +ctx->ct_hdr = AES_CT_CTRL_HDR | cpu_to_le32(len);
>
>  info->cmd[cnt++] = AES_GCM_CMD0 | cpu_to_le32(req->assoclen);
>  info->cmd[cnt++] = AES_GCM_CMD1 | cpu_to_le32(req->assoclen);
> @@ -889,8 +872,8 @@ static void mtk_aes_gcm_info_init(struct mtk_cryp *cryp,
>  info->tfm[1] = AES_TFM_CTR_INIT | AES_TFM_IV_CTR_MODE | AES_TFM_3IV |
>         AES_TFM_ENC_HASH;
>
> -mtk_aes_write_state_le(info->state + ctx->keylen + SIZE_IN_WORDS(
> -       AES_BLOCK_SIZE), (const u32 *)req->iv, ivsize);
> +memcpy(info->state + ctx->keylen + SIZE_IN_WORDS(AES_BLOCK_SIZE),
> +       req->iv, ivsize);
>  }
>
>  static int mtk_aes_gcm_dma(struct mtk_cryp *cryp, struct mtk_aes_rec *aes,
> @@ -994,9 +977,13 @@ static int mtk_aes_gcm_setkey(struct crypto_aead *aead, const u8 *key,
>        u32 keylen)
>  {
>  struct mtk_aes_base_ctx *ctx = crypto_aead_ctx(aead);
> -u8 hash[AES_BLOCK_SIZE] __aligned(4) = {};
> +union {
> +u32 x32[SIZE_IN_WORDS(AES_BLOCK_SIZE)];
> +u8 x8[AES_BLOCK_SIZE];
> +} hash = {};
>  struct crypto_aes_ctx aes_ctx;
>  int err;
> +int i;
>
>  switch (keylen) {
>  case AES_KEYSIZE_128:
> @@ -1019,12 +1006,16 @@ static int mtk_aes_gcm_setkey(struct crypto_aead *aead, const u8 *key,
>  if (err)
>  return err;
>
> -aes_encrypt(&aes_ctx, hash, hash);
> +aes_encrypt(&aes_ctx, hash.x8, hash.x8);
>  memzero_explicit(&aes_ctx, sizeof(aes_ctx));
>
> -mtk_aes_write_state_le(ctx->key, (const u32 *)key, keylen);
> -mtk_aes_write_state_be(ctx->key + ctx->keylen, (const u32 *)hash,
> -       AES_BLOCK_SIZE);
> +memcpy(ctx->key, key, keylen);
> +
> +/* Why do we need to do this? */
> +for (i = 0; i < SIZE_IN_WORDS(AES_BLOCK_SIZE); i++)
> +hash.x32[i] = swab32(hash.x32[i]);
> +
> +memcpy(ctx->key + ctx->keylen, &hash, AES_BLOCK_SIZE);
>
>  return 0;
>  }
> diff --git a/drivers/crypto/mediatek/mtk-sha.c b/drivers/crypto/mediatek/mtk-sha.c
> index da3f0b8814aa..3d5d7d68b03b 100644
> --- a/drivers/crypto/mediatek/mtk-sha.c
> +++ b/drivers/crypto/mediatek/mtk-sha.c
> @@ -239,7 +239,7 @@ static int mtk_sha_append_sg(struct mtk_sha_reqctx *ctx)
>  static void mtk_sha_fill_padding(struct mtk_sha_reqctx *ctx, u32 len)
>  {
>  u32 index, padlen;
> -u64 bits[2];
> +__be64 bits[2];
>  u64 size = ctx->digcnt;
>
>  size += ctx->bufcnt;
> --
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Regards,
Pascal van Leeuwen
Silicon IP Architect Multi-Protocol Engines, Rambus Security
Rambus ROTW Holding BV
+31-73 6581953

Note: The Inside Secure/Verimatrix Silicon IP team was recently acquired by Rambus.
Please be so kind to update your e-mail address book with my new e-mail address.


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