[PATCH v3 2/4] crypto: talitos - fix hash on SEC1.

Horia Geanta horia.geanta at nxp.com
Fri Jun 14 05:07:16 AEST 2019


On 6/13/2019 3:48 PM, Christophe Leroy wrote:
> On SEC1, hash provides wrong result when performing hashing in several
> steps with input data SG list has more than one element. This was
> detected with CONFIG_CRYPTO_MANAGER_EXTRA_TESTS:
> 
> [   44.185947] alg: hash: md5-talitos test failed (wrong result) on test vector 6, cfg="random: may_sleep use_finup src_divs=[<reimport>25.88%@+8063, <flush>24.19%@+9588, 28.63%@+16333, <reimport>4.60%@+6756, 16.70%@+16281] dst_divs=[71.61%@alignmask+16361, 14.36%@+7756, 14.3%@+"
> [   44.325122] alg: hash: sha1-talitos test failed (wrong result) on test vector 3, cfg="random: inplace use_final src_divs=[<flush,nosimd>16.56%@+16378, <reimport>52.0%@+16329, 21.42%@alignmask+16380, 10.2%@alignmask+16380] iv_offset=39"
> [   44.493500] alg: hash: sha224-talitos test failed (wrong result) on test vector 4, cfg="random: use_final nosimd src_divs=[<reimport>52.27%@+7401, <reimport>17.34%@+16285, <flush>17.71%@+26, 12.68%@+10644] iv_offset=43"
> [   44.673262] alg: hash: sha256-talitos test failed (wrong result) on test vector 4, cfg="random: may_sleep use_finup src_divs=[<reimport>60.6%@+12790, 17.86%@+1329, <reimport>12.64%@alignmask+16300, 8.29%@+15, 0.40%@+13506, <reimport>0.51%@+16322, <reimport>0.24%@+16339] dst_divs"
> 
> This is due to two issues:
> - We have an overlap between the buffer used for copying the input
> data (SEC1 doesn't do scatter/gather) and the chained descriptor.
> - Data copy is wrong when the previous hash left less than one
> blocksize of data to hash, implying a complement of the previous
> block with a few bytes from the new request.
> 
I fail to spot these issues.

IIUC in case of SEC1, the variable part of talitos_edesc structure contains
a 2nd "chained" descriptor (talitos_desc struct) followed by an area
dedicated to linearizing the input (in case input is scattered).

Where is the overlap?

> Fix it by:
> - Moving the second descriptor after the buffer, as moving the buffer
> after the descriptor would make it more complex for other cipher
> operations (AEAD, ABLKCIPHER)
> - Rebuiding a new data SG list without the bytes taken from the new
> request to complete the previous one.
> 
> Preceding patch ("crypto: talitos - move struct talitos_edesc into
> talitos.h") as required for this change to build properly.
> 
> Fixes: 37b5e8897eb5 ("crypto: talitos - chain in buffered data for ahash on SEC1")
> Cc: stable at vger.kernel.org
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
> ---
>  drivers/crypto/talitos.c | 63 ++++++++++++++++++++++++++++++------------------
>  1 file changed, 40 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c
> index 5b401aec6c84..4f03baef952b 100644
> --- a/drivers/crypto/talitos.c
> +++ b/drivers/crypto/talitos.c
> @@ -336,15 +336,18 @@ static void flush_channel(struct device *dev, int ch, int error, int reset_ch)
>  	tail = priv->chan[ch].tail;
>  	while (priv->chan[ch].fifo[tail].desc) {
>  		__be32 hdr;
> +		struct talitos_edesc *edesc;
>  
>  		request = &priv->chan[ch].fifo[tail];
> +		edesc = container_of(request->desc, struct talitos_edesc, desc);
>  
>  		/* descriptors with their done bits set don't get the error */
>  		rmb();
>  		if (!is_sec1)
>  			hdr = request->desc->hdr;
>  		else if (request->desc->next_desc)
> -			hdr = (request->desc + 1)->hdr1;
> +			hdr = ((struct talitos_desc *)
> +			       (edesc->buf + edesc->dma_len))->hdr1;
>  		else
>  			hdr = request->desc->hdr1;
>  
> @@ -476,8 +479,14 @@ static u32 current_desc_hdr(struct device *dev, int ch)
>  		}
>  	}
>  
> -	if (priv->chan[ch].fifo[iter].desc->next_desc == cur_desc)
> -		return (priv->chan[ch].fifo[iter].desc + 1)->hdr;
> +	if (priv->chan[ch].fifo[iter].desc->next_desc == cur_desc) {
> +		struct talitos_edesc *edesc;
> +
> +		edesc = container_of(priv->chan[ch].fifo[iter].desc,
> +				     struct talitos_edesc, desc);
> +		return ((struct talitos_desc *)
> +			(edesc->buf + edesc->dma_len))->hdr;
> +	}
>  
>  	return priv->chan[ch].fifo[iter].desc->hdr;
>  }
> @@ -1402,15 +1411,11 @@ static struct talitos_edesc *talitos_edesc_alloc(struct device *dev,
>  	edesc->dst_nents = dst_nents;
>  	edesc->iv_dma = iv_dma;
>  	edesc->dma_len = dma_len;
> -	if (dma_len) {
> -		void *addr = &edesc->link_tbl[0];
> -
> -		if (is_sec1 && !dst)
> -			addr += sizeof(struct talitos_desc);
> -		edesc->dma_link_tbl = dma_map_single(dev, addr,
> +	if (dma_len)
> +		edesc->dma_link_tbl = dma_map_single(dev, &edesc->link_tbl[0],
>  						     edesc->dma_len,
>  						     DMA_BIDIRECTIONAL);
> -	}
> +
>  	return edesc;
>  }
>  
> @@ -1722,14 +1727,16 @@ static void common_nonsnoop_hash_unmap(struct device *dev,
>  	struct talitos_private *priv = dev_get_drvdata(dev);
>  	bool is_sec1 = has_ftr_sec1(priv);
>  	struct talitos_desc *desc = &edesc->desc;
> -	struct talitos_desc *desc2 = desc + 1;
> +	struct talitos_desc *desc2 = (struct talitos_desc *)
> +				     (edesc->buf + edesc->dma_len);
>  
>  	unmap_single_talitos_ptr(dev, &edesc->desc.ptr[5], DMA_FROM_DEVICE);
>  	if (desc->next_desc &&
>  	    desc->ptr[5].ptr != desc2->ptr[5].ptr)
>  		unmap_single_talitos_ptr(dev, &desc2->ptr[5], DMA_FROM_DEVICE);
>  
> -	talitos_sg_unmap(dev, edesc, req_ctx->psrc, NULL, 0, 0);
> +	if (req_ctx->psrc)
> +		talitos_sg_unmap(dev, edesc, req_ctx->psrc, NULL, 0, 0);
>  
>  	/* When using hashctx-in, must unmap it. */
>  	if (from_talitos_ptr_len(&edesc->desc.ptr[1], is_sec1))
> @@ -1796,7 +1803,6 @@ static void talitos_handle_buggy_hash(struct talitos_ctx *ctx,
>  
>  static int common_nonsnoop_hash(struct talitos_edesc *edesc,
>  				struct ahash_request *areq, unsigned int length,
> -				unsigned int offset,
>  				void (*callback) (struct device *dev,
>  						  struct talitos_desc *desc,
>  						  void *context, int error))
> @@ -1835,9 +1841,7 @@ static int common_nonsnoop_hash(struct talitos_edesc *edesc,
>  
>  	sg_count = edesc->src_nents ?: 1;
>  	if (is_sec1 && sg_count > 1)
> -		sg_pcopy_to_buffer(req_ctx->psrc, sg_count,
> -				   edesc->buf + sizeof(struct talitos_desc),
> -				   length, req_ctx->nbuf);
> +		sg_copy_to_buffer(req_ctx->psrc, sg_count, edesc->buf, length);
>  	else if (length)
>  		sg_count = dma_map_sg(dev, req_ctx->psrc, sg_count,
>  				      DMA_TO_DEVICE);
> @@ -1850,7 +1854,7 @@ static int common_nonsnoop_hash(struct talitos_edesc *edesc,
>  				       DMA_TO_DEVICE);
>  	} else {
>  		sg_count = talitos_sg_map(dev, req_ctx->psrc, length, edesc,
> -					  &desc->ptr[3], sg_count, offset, 0);
> +					  &desc->ptr[3], sg_count, 0, 0);
>  		if (sg_count > 1)
>  			sync_needed = true;
>  	}
> @@ -1874,7 +1878,8 @@ static int common_nonsnoop_hash(struct talitos_edesc *edesc,
>  		talitos_handle_buggy_hash(ctx, edesc, &desc->ptr[3]);
>  
>  	if (is_sec1 && req_ctx->nbuf && length) {
> -		struct talitos_desc *desc2 = desc + 1;
> +		struct talitos_desc *desc2 = (struct talitos_desc *)
> +					     (edesc->buf + edesc->dma_len);
>  		dma_addr_t next_desc;
>  
>  		memset(desc2, 0, sizeof(*desc2));
> @@ -1895,7 +1900,7 @@ static int common_nonsnoop_hash(struct talitos_edesc *edesc,
>  						      DMA_TO_DEVICE);
>  		copy_talitos_ptr(&desc2->ptr[2], &desc->ptr[2], is_sec1);
>  		sg_count = talitos_sg_map(dev, req_ctx->psrc, length, edesc,
> -					  &desc2->ptr[3], sg_count, offset, 0);
> +					  &desc2->ptr[3], sg_count, 0, 0);
>  		if (sg_count > 1)
>  			sync_needed = true;
>  		copy_talitos_ptr(&desc2->ptr[5], &desc->ptr[5], is_sec1);
> @@ -2006,7 +2011,6 @@ static int ahash_process_req(struct ahash_request *areq, unsigned int nbytes)
>  	struct device *dev = ctx->dev;
>  	struct talitos_private *priv = dev_get_drvdata(dev);
>  	bool is_sec1 = has_ftr_sec1(priv);
> -	int offset = 0;
>  	u8 *ctx_buf = req_ctx->buf[req_ctx->buf_idx];
>  
>  	if (!req_ctx->last && (nbytes + req_ctx->nbuf <= blocksize)) {
> @@ -2046,6 +2050,9 @@ static int ahash_process_req(struct ahash_request *areq, unsigned int nbytes)
>  			sg_chain(req_ctx->bufsl, 2, areq->src);
>  		req_ctx->psrc = req_ctx->bufsl;
>  	} else if (is_sec1 && req_ctx->nbuf && req_ctx->nbuf < blocksize) {
> +		int offset;
> +		struct scatterlist *sg;
> +
>  		if (nbytes_to_hash > blocksize)
>  			offset = blocksize - req_ctx->nbuf;
>  		else
> @@ -2058,7 +2065,18 @@ static int ahash_process_req(struct ahash_request *areq, unsigned int nbytes)
>  		sg_copy_to_buffer(areq->src, nents,
>  				  ctx_buf + req_ctx->nbuf, offset);
>  		req_ctx->nbuf += offset;
> -		req_ctx->psrc = areq->src;
> +		for (sg = areq->src; sg && offset >= sg->length;
> +		     offset -= sg->length, sg = sg_next(sg))
> +			;
> +		if (offset) {
> +			sg_init_table(req_ctx->bufsl, 2);
> +			sg_set_buf(req_ctx->bufsl, sg_virt(sg) + offset,
> +				   sg->length - offset);
> +			sg_chain(req_ctx->bufsl, 2, sg_next(sg));
> +			req_ctx->psrc = req_ctx->bufsl;
> +		} else {
> +			req_ctx->psrc = sg;
> +		}
>  	} else
>  		req_ctx->psrc = areq->src;
>  
> @@ -2098,8 +2116,7 @@ static int ahash_process_req(struct ahash_request *areq, unsigned int nbytes)
>  	if (ctx->keylen && (req_ctx->first || req_ctx->last))
>  		edesc->desc.hdr |= DESC_HDR_MODE0_MDEU_HMAC;
>  
> -	return common_nonsnoop_hash(edesc, areq, nbytes_to_hash, offset,
> -				    ahash_done);
> +	return common_nonsnoop_hash(edesc, areq, nbytes_to_hash, ahash_done);
>  }
>  
>  static int ahash_update(struct ahash_request *areq)
> 


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