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Message-ID: <548bea7c-fa35-3c17-ee21-61aeb3c59b9a@c-s.fr>
Date: Fri, 14 Jun 2019 09:57:53 +0200
From: Christophe Leroy <christophe.leroy@....fr>
To: Horia Geanta <horia.geanta@....com>,
Herbert Xu <herbert@...dor.apana.org.au>,
"David S. Miller" <davem@...emloft.net>
Cc: "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH v3 2/4] crypto: talitos - fix hash on SEC1.
Le 13/06/2019 à 21:07, Horia Geanta a écrit :
> 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%@...63, <flush>24.19%@...88, 28.63%@...333, <reimport>4.60%@...56, 16.70%@...281] dst_divs=[71.61%@...gnmask+16361, 14.36%@...56, 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%@...378, <reimport>52.0%@...329, 21.42%@...gnmask+16380, 10.2%@...gnmask+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%@...01, <reimport>17.34%@...285, <flush>17.71%@+26, 12.68%@...644] 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%@...790, 17.86%@...29, <reimport>12.64%@...gnmask+16300, 8.29%@+15, 0.40%@...506, <reimport>0.51%@...322, <reimport>0.24%@...339] 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?
talitos_sg_map() maps the area starting at edesc->dma_link_tbl, which
corresponds to the start of the variable part of talitos_edesc
structure. When we use the second descriptor, the data is after that
descriptor, but talitos_sg_map() is not aware of it so it maps the
second descriptor followed by part of the data instead of mapping the data.
Christophe
>
>> 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@...r.kernel.org
>> Signed-off-by: Christophe Leroy <christophe.leroy@....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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