crypto: caam - fix IV DMA mapping and updating

There are two IV-related issues:
(1) crypto API does not guarantee to provide an IV buffer that is DMAable,
thus it's incorrect to DMA map it
(2) for in-place decryption, since ciphertext is overwritten with
plaintext, updated req->info will contain the last block of plaintext
(instead of the last block of ciphertext)

While these two issues could be fixed separately, it's straightforward
to fix both in the same time - by allocating extra space in the
ablkcipher_edesc for the IV that will be fed to the crypto engine;
this allows for fixing (2) by saving req->src[last_block] in req->info
directly, i.e. without allocating another temporary buffer.

A side effect of the fix is that it's no longer possible to have the IV
and req->src contiguous. Code checking for this case is removed.

Cc: <stable@vger.kernel.org> # 4.13+
Fixes: 854b06f76879 ("crypto: caam - properly set IV after {en,de}crypt")
Link: http://lkml.kernel.org/r/20170113084620.GF22022@gondor.apana.org.au
Reported-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamalg.c

@@ -774,6 +774,7 @@ struct aead_edesc {
  * @sec4_sg_dma: bus physical mapped address of h/w link table
  * @sec4_sg: pointer to h/w link table
  * @hw_desc: the h/w job descriptor followed by any referenced link tables
+ *	     and IV
  */
 struct ablkcipher_edesc {
 	int src_nents;
@@ -915,6 +916,18 @@ static void ablkcipher_encrypt_done(struct device *jrdev, u32 *desc, u32 err,
 	scatterwalk_map_and_copy(req->info, req->dst, req->nbytes - ivsize,
 				 ivsize, 0);
 
+	/* In case initial IV was generated, copy it in GIVCIPHER request */
+	if (edesc->iv_dir == DMA_FROM_DEVICE) {
+		u8 *iv;
+		struct skcipher_givcrypt_request *greq;
+
+		greq = container_of(req, struct skcipher_givcrypt_request,
+				    creq);
+		iv = (u8 *)edesc->hw_desc + desc_bytes(edesc->hw_desc) +
+		     edesc->sec4_sg_bytes;
+		memcpy(greq->giv, iv, ivsize);
+	}
+
 	kfree(edesc);
 
 	ablkcipher_request_complete(req, err);
@@ -925,10 +938,10 @@ static void ablkcipher_decrypt_done(struct device *jrdev, u32 *desc, u32 err,
 {
 	struct ablkcipher_request *req = context;
 	struct ablkcipher_edesc *edesc;
+#ifdef DEBUG
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
 	int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 
-#ifdef DEBUG
 	dev_err(jrdev, "%s %d: err 0x%x\n", __func__, __LINE__, err);
 #endif
 
@@ -946,14 +959,6 @@ static void ablkcipher_decrypt_done(struct device *jrdev, u32 *desc, u32 err,
 		     edesc->dst_nents > 1 ? 100 : req->nbytes, 1);
 
 	ablkcipher_unmap(jrdev, edesc, req);
-
-	/*
-	 * The crypto API expects us to set the IV (req->info) to the last
-	 * ciphertext block.
-	 */
-	scatterwalk_map_and_copy(req->info, req->src, req->nbytes - ivsize,
-				 ivsize, 0);
-
 	kfree(edesc);
 
 	ablkcipher_request_complete(req, err);
@@ -1102,15 +1107,14 @@ static void init_authenc_job(struct aead_request *req,
  */
 static void init_ablkcipher_job(u32 *sh_desc, dma_addr_t ptr,
 				struct ablkcipher_edesc *edesc,
-				struct ablkcipher_request *req,
-				bool iv_contig)
+				struct ablkcipher_request *req)
 {
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
 	int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 	u32 *desc = edesc->hw_desc;
-	u32 out_options = 0, in_options;
-	dma_addr_t dst_dma, src_dma;
-	int len, sec4_sg_index = 0;
+	u32 out_options = 0;
+	dma_addr_t dst_dma;
+	int len;
 
 #ifdef DEBUG
 	print_hex_dump(KERN_ERR, "presciv@"__stringify(__LINE__)": ",
@@ -1126,30 +1130,18 @@ static void init_ablkcipher_job(u32 *sh_desc, dma_addr_t ptr,
 	len = desc_len(sh_desc);
 	init_job_desc_shared(desc, ptr, len, HDR_SHARE_DEFER | HDR_REVERSE);
 
-	if (iv_contig) {
-		src_dma = edesc->iv_dma;
-		in_options = 0;
-	} else {
-		src_dma = edesc->sec4_sg_dma;
-		sec4_sg_index += edesc->src_nents + 1;
-		in_options = LDST_SGF;
-	}
-	append_seq_in_ptr(desc, src_dma, req->nbytes + ivsize, in_options);
+	append_seq_in_ptr(desc, edesc->sec4_sg_dma, req->nbytes + ivsize,
+			  LDST_SGF);
 
 	if (likely(req->src == req->dst)) {
-		if (edesc->src_nents == 1 && iv_contig) {
-			dst_dma = sg_dma_address(req->src);
-		} else {
-			dst_dma = edesc->sec4_sg_dma +
-				sizeof(struct sec4_sg_entry);
-			out_options = LDST_SGF;
-		}
+		dst_dma = edesc->sec4_sg_dma + sizeof(struct sec4_sg_entry);
+		out_options = LDST_SGF;
 	} else {
 		if (edesc->dst_nents == 1) {
 			dst_dma = sg_dma_address(req->dst);
 		} else {
-			dst_dma = edesc->sec4_sg_dma +
-				sec4_sg_index * sizeof(struct sec4_sg_entry);
+			dst_dma = edesc->sec4_sg_dma + (edesc->src_nents + 1) *
+				  sizeof(struct sec4_sg_entry);
 			out_options = LDST_SGF;
 		}
 	}
@@ -1161,13 +1153,12 @@ static void init_ablkcipher_job(u32 *sh_desc, dma_addr_t ptr,
  */
 static void init_ablkcipher_giv_job(u32 *sh_desc, dma_addr_t ptr,
 				    struct ablkcipher_edesc *edesc,
-				    struct ablkcipher_request *req,
-				    bool iv_contig)
+				    struct ablkcipher_request *req)
 {
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
 	int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 	u32 *desc = edesc->hw_desc;
-	u32 out_options, in_options;
+	u32 in_options;
 	dma_addr_t dst_dma, src_dma;
 	int len, sec4_sg_index = 0;
 
@@ -1193,15 +1184,9 @@ static void init_ablkcipher_giv_job(u32 *sh_desc, dma_addr_t ptr,
 	}
 	append_seq_in_ptr(desc, src_dma, req->nbytes, in_options);
 
-	if (iv_contig) {
-		dst_dma = edesc->iv_dma;
-		out_options = 0;
-	} else {
-		dst_dma = edesc->sec4_sg_dma +
-			  sec4_sg_index * sizeof(struct sec4_sg_entry);
-		out_options = LDST_SGF;
-	}
-	append_seq_out_ptr(desc, dst_dma, req->nbytes + ivsize, out_options);
+	dst_dma = edesc->sec4_sg_dma + sec4_sg_index *
+		  sizeof(struct sec4_sg_entry);
+	append_seq_out_ptr(desc, dst_dma, req->nbytes + ivsize, LDST_SGF);
 }
 
 /*
@@ -1494,8 +1479,7 @@ static int aead_decrypt(struct aead_request *req)
  * allocate and map the ablkcipher extended descriptor for ablkcipher
  */
 static struct ablkcipher_edesc *ablkcipher_edesc_alloc(struct ablkcipher_request
-						       *req, int desc_bytes,
-						       bool *iv_contig_out)
+						       *req, int desc_bytes)
 {
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
 	struct caam_ctx *ctx = crypto_ablkcipher_ctx(ablkcipher);
@@ -1504,8 +1488,8 @@ static struct ablkcipher_edesc *ablkcipher_edesc_alloc(struct ablkcipher_request
 		       GFP_KERNEL : GFP_ATOMIC;
 	int src_nents, mapped_src_nents, dst_nents = 0, mapped_dst_nents = 0;
 	struct ablkcipher_edesc *edesc;
-	dma_addr_t iv_dma = 0;
-	bool in_contig;
+	dma_addr_t iv_dma;
+	u8 *iv;
 	int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 	int dst_sg_idx, sec4_sg_ents, sec4_sg_bytes;
 
@@ -1549,33 +1533,20 @@ static struct ablkcipher_edesc *ablkcipher_edesc_alloc(struct ablkcipher_request
 		}
 	}
 
-	iv_dma = dma_map_single(jrdev, req->info, ivsize, DMA_TO_DEVICE);
-	if (dma_mapping_error(jrdev, iv_dma)) {
-		dev_err(jrdev, "unable to map IV\n");
-		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents, 0,
-			   0, DMA_NONE, 0, 0);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	if (mapped_src_nents == 1 &&
-	    iv_dma + ivsize == sg_dma_address(req->src)) {
-		in_contig = true;
-		sec4_sg_ents = 0;
-	} else {
-		in_contig = false;
-		sec4_sg_ents = 1 + mapped_src_nents;
-	}
+	sec4_sg_ents = 1 + mapped_src_nents;
 	dst_sg_idx = sec4_sg_ents;
 	sec4_sg_ents += mapped_dst_nents > 1 ? mapped_dst_nents : 0;
 	sec4_sg_bytes = sec4_sg_ents * sizeof(struct sec4_sg_entry);
 
-	/* allocate space for base edesc and hw desc commands, link tables */
-	edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes,
+	/*
+	 * allocate space for base edesc and hw desc commands, link tables, IV
+	 */
+	edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes + ivsize,
 			GFP_DMA | flags);
 	if (!edesc) {
 		dev_err(jrdev, "could not allocate extended descriptor\n");
-		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
-			   iv_dma, ivsize, DMA_TO_DEVICE, 0, 0);
+		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents, 0,
+			   0, DMA_NONE, 0, 0);
 		return ERR_PTR(-ENOMEM);
 	}
 
@@ -1586,12 +1557,22 @@ static struct ablkcipher_edesc *ablkcipher_edesc_alloc(struct ablkcipher_request
 			 desc_bytes;
 	edesc->iv_dir = DMA_TO_DEVICE;
 
-	if (!in_contig) {
-		dma_to_sec4_sg_one(edesc->sec4_sg, iv_dma, ivsize, 0);
-		sg_to_sec4_sg_last(req->src, mapped_src_nents,
-				   edesc->sec4_sg + 1, 0);
+	/* Make sure IV is located in a DMAable area */
+	iv = (u8 *)edesc->hw_desc + desc_bytes + sec4_sg_bytes;
+	memcpy(iv, req->info, ivsize);
+
+	iv_dma = dma_map_single(jrdev, iv, ivsize, DMA_TO_DEVICE);
+	if (dma_mapping_error(jrdev, iv_dma)) {
+		dev_err(jrdev, "unable to map IV\n");
+		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents, 0,
+			   0, DMA_NONE, 0, 0);
+		kfree(edesc);
+		return ERR_PTR(-ENOMEM);
 	}
 
+	dma_to_sec4_sg_one(edesc->sec4_sg, iv_dma, ivsize, 0);
+	sg_to_sec4_sg_last(req->src, mapped_src_nents, edesc->sec4_sg + 1, 0);
+
 	if (mapped_dst_nents > 1) {
 		sg_to_sec4_sg_last(req->dst, mapped_dst_nents,
 				   edesc->sec4_sg + dst_sg_idx, 0);
@@ -1615,7 +1596,6 @@ static struct ablkcipher_edesc *ablkcipher_edesc_alloc(struct ablkcipher_request
 		       sec4_sg_bytes, 1);
 #endif
 
-	*iv_contig_out = in_contig;
 	return edesc;
 }
 
@@ -1625,19 +1605,16 @@ static int ablkcipher_encrypt(struct ablkcipher_request *req)
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
 	struct caam_ctx *ctx = crypto_ablkcipher_ctx(ablkcipher);
 	struct device *jrdev = ctx->jrdev;
-	bool iv_contig;
 	u32 *desc;
 	int ret = 0;
 
 	/* allocate extended descriptor */
-	edesc = ablkcipher_edesc_alloc(req, DESC_JOB_IO_LEN *
-				       CAAM_CMD_SZ, &iv_contig);
+	edesc = ablkcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ);
 	if (IS_ERR(edesc))
 		return PTR_ERR(edesc);
 
 	/* Create and submit job descriptor*/
-	init_ablkcipher_job(ctx->sh_desc_enc,
-		ctx->sh_desc_enc_dma, edesc, req, iv_contig);
+	init_ablkcipher_job(ctx->sh_desc_enc, ctx->sh_desc_enc_dma, edesc, req);
 #ifdef DEBUG
 	print_hex_dump(KERN_ERR, "ablkcipher jobdesc@"__stringify(__LINE__)": ",
 		       DUMP_PREFIX_ADDRESS, 16, 4, edesc->hw_desc,
@@ -1661,20 +1638,25 @@ static int ablkcipher_decrypt(struct ablkcipher_request *req)
 	struct ablkcipher_edesc *edesc;
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
 	struct caam_ctx *ctx = crypto_ablkcipher_ctx(ablkcipher);
+	int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 	struct device *jrdev = ctx->jrdev;
-	bool iv_contig;
 	u32 *desc;
 	int ret = 0;
 
 	/* allocate extended descriptor */
-	edesc = ablkcipher_edesc_alloc(req, DESC_JOB_IO_LEN *
-				       CAAM_CMD_SZ, &iv_contig);
+	edesc = ablkcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ);
 	if (IS_ERR(edesc))
 		return PTR_ERR(edesc);
 
+	/*
+	 * The crypto API expects us to set the IV (req->info) to the last
+	 * ciphertext block.
+	 */
+	scatterwalk_map_and_copy(req->info, req->src, req->nbytes - ivsize,
+				 ivsize, 0);
+
 	/* Create and submit job descriptor*/
-	init_ablkcipher_job(ctx->sh_desc_dec,
-		ctx->sh_desc_dec_dma, edesc, req, iv_contig);
+	init_ablkcipher_job(ctx->sh_desc_dec, ctx->sh_desc_dec_dma, edesc, req);
 	desc = edesc->hw_desc;
 #ifdef DEBUG
 	print_hex_dump(KERN_ERR, "ablkcipher jobdesc@"__stringify(__LINE__)": ",
@@ -1699,8 +1681,7 @@ static int ablkcipher_decrypt(struct ablkcipher_request *req)
  */
 static struct ablkcipher_edesc *ablkcipher_giv_edesc_alloc(
 				struct skcipher_givcrypt_request *greq,
-				int desc_bytes,
-				bool *iv_contig_out)
+				int desc_bytes)
 {
 	struct ablkcipher_request *req = &greq->creq;
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
@@ -1710,8 +1691,8 @@ static struct ablkcipher_edesc *ablkcipher_giv_edesc_alloc(
 		       GFP_KERNEL : GFP_ATOMIC;
 	int src_nents, mapped_src_nents, dst_nents, mapped_dst_nents;
 	struct ablkcipher_edesc *edesc;
-	dma_addr_t iv_dma = 0;
-	bool out_contig;
+	dma_addr_t iv_dma;
+	u8 *iv;
 	int ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 	int dst_sg_idx, sec4_sg_ents, sec4_sg_bytes;
 
@@ -1756,36 +1737,20 @@ static struct ablkcipher_edesc *ablkcipher_giv_edesc_alloc(
 		}
 	}
 
-	/*
-	 * Check if iv can be contiguous with source and destination.
-	 * If so, include it. If not, create scatterlist.
-	 */
-	iv_dma = dma_map_single(jrdev, greq->giv, ivsize, DMA_FROM_DEVICE);
-	if (dma_mapping_error(jrdev, iv_dma)) {
-		dev_err(jrdev, "unable to map IV\n");
-		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents, 0,
-			   0, DMA_NONE, 0, 0);
-		return ERR_PTR(-ENOMEM);
-	}
-
 	sec4_sg_ents = mapped_src_nents > 1 ? mapped_src_nents : 0;
 	dst_sg_idx = sec4_sg_ents;
-	if (mapped_dst_nents == 1 &&
-	    iv_dma + ivsize == sg_dma_address(req->dst)) {
-		out_contig = true;
-	} else {
-		out_contig = false;
-		sec4_sg_ents += 1 + mapped_dst_nents;
-	}
+	sec4_sg_ents += 1 + mapped_dst_nents;
 
-	/* allocate space for base edesc and hw desc commands, link tables */
+	/*
+	 * allocate space for base edesc and hw desc commands, link tables, IV
+	 */
 	sec4_sg_bytes = sec4_sg_ents * sizeof(struct sec4_sg_entry);
-	edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes,
+	edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes + ivsize,
 			GFP_DMA | flags);
 	if (!edesc) {
 		dev_err(jrdev, "could not allocate extended descriptor\n");
-		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
-			   iv_dma, ivsize, DMA_FROM_DEVICE, 0, 0);
+		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents, 0,
+			   0, DMA_NONE, 0, 0);
 		return ERR_PTR(-ENOMEM);
 	}
 
@@ -1796,16 +1761,24 @@ static struct ablkcipher_edesc *ablkcipher_giv_edesc_alloc(
 			 desc_bytes;
 	edesc->iv_dir = DMA_FROM_DEVICE;
 
+	/* Make sure IV is located in a DMAable area */
+	iv = (u8 *)edesc->hw_desc + desc_bytes + sec4_sg_bytes;
+	iv_dma = dma_map_single(jrdev, iv, ivsize, DMA_FROM_DEVICE);
+	if (dma_mapping_error(jrdev, iv_dma)) {
+		dev_err(jrdev, "unable to map IV\n");
+		caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents, 0,
+			   0, DMA_NONE, 0, 0);
+		kfree(edesc);
+		return ERR_PTR(-ENOMEM);
+	}
+
 	if (mapped_src_nents > 1)
 		sg_to_sec4_sg_last(req->src, mapped_src_nents, edesc->sec4_sg,
 				   0);
 
-	if (!out_contig) {
-		dma_to_sec4_sg_one(edesc->sec4_sg + dst_sg_idx,
-				   iv_dma, ivsize, 0);
-		sg_to_sec4_sg_last(req->dst, mapped_dst_nents,
-				   edesc->sec4_sg + dst_sg_idx + 1, 0);
-	}
+	dma_to_sec4_sg_one(edesc->sec4_sg + dst_sg_idx, iv_dma, ivsize, 0);
+	sg_to_sec4_sg_last(req->dst, mapped_dst_nents, edesc->sec4_sg +
+			   dst_sg_idx + 1, 0);
 
 	edesc->sec4_sg_dma = dma_map_single(jrdev, edesc->sec4_sg,
 					    sec4_sg_bytes, DMA_TO_DEVICE);
@@ -1825,7 +1798,6 @@ static struct ablkcipher_edesc *ablkcipher_giv_edesc_alloc(
 		       sec4_sg_bytes, 1);
 #endif
 
-	*iv_contig_out = out_contig;
 	return edesc;
 }
 
@@ -1836,19 +1808,17 @@ static int ablkcipher_givencrypt(struct skcipher_givcrypt_request *creq)
 	struct crypto_ablkcipher *ablkcipher = crypto_ablkcipher_reqtfm(req);
 	struct caam_ctx *ctx = crypto_ablkcipher_ctx(ablkcipher);
 	struct device *jrdev = ctx->jrdev;
-	bool iv_contig = false;
 	u32 *desc;
 	int ret = 0;
 
 	/* allocate extended descriptor */
-	edesc = ablkcipher_giv_edesc_alloc(creq, DESC_JOB_IO_LEN *
-				       CAAM_CMD_SZ, &iv_contig);
+	edesc = ablkcipher_giv_edesc_alloc(creq, DESC_JOB_IO_LEN * CAAM_CMD_SZ);
 	if (IS_ERR(edesc))
 		return PTR_ERR(edesc);
 
 	/* Create and submit job descriptor*/
 	init_ablkcipher_giv_job(ctx->sh_desc_givenc, ctx->sh_desc_givenc_dma,
-				edesc, req, iv_contig);
+				edesc, req);
 #ifdef DEBUG
 	print_hex_dump(KERN_ERR,
 		       "ablkcipher jobdesc@" __stringify(__LINE__) ": ",