crypto: nx - Moving NX-AES-CCM to be processed logic and sg_list bounds

The previous limits were estimated locally in a single step
basead on bound values, however it was not correct since
when given certain scatterlist the function nx_build_sg_lists
was consuming more sg entries than allocated causing a
memory corruption and crashes.

This patch removes the old logic and replaces it into nx_sg_build_lists in
order to build a correct nx_sg list using the correct sg_max limit and
bounds.
Signed-off-by: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/nx/nx-aes-ccm.c

@@ -181,6 +181,7 @@ static int generate_pat(u8                   *iv,
 	unsigned int iauth_len = 0;
 	u8 tmp[16], *b1 = NULL, *b0 = NULL, *result = NULL;
 	int rc;
+	unsigned int max_sg_len;
 
 	/* zero the ctr value */
 	memset(iv + 15 - iv[0], 0, iv[0] + 1);
@@ -248,10 +249,19 @@ static int generate_pat(u8                   *iv,
 	if (!req->assoclen) {
 		return rc;
 	} else if (req->assoclen <= 14) {
-		nx_insg = nx_build_sg_list(nx_insg, b1, 16, nx_ctx->ap->sglen);
-		nx_outsg = nx_build_sg_list(nx_outsg, tmp, 16,
+		unsigned int len = 16;
+
+		nx_insg = nx_build_sg_list(nx_insg, b1, &len, nx_ctx->ap->sglen);
+
+		if (len != 16)
+			return -EINVAL;
+
+		nx_outsg = nx_build_sg_list(nx_outsg, tmp, &len,
 					    nx_ctx->ap->sglen);
 
+		if (len != 16)
+			return -EINVAL;
+
 		/* inlen should be negative, indicating to phyp that its a
 		 * pointer to an sg list */
 		nx_ctx->op.inlen = (nx_ctx->in_sg - nx_insg) *
@@ -273,21 +283,24 @@ static int generate_pat(u8                   *iv,
 		atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));
 
 	} else {
-		u32 max_sg_len;
 		unsigned int processed = 0, to_process;
 
-		/* page_limit: number of sg entries that fit on one page */
-		max_sg_len = min_t(u32,
-				   nx_driver.of.max_sg_len/sizeof(struct nx_sg),
-				   nx_ctx->ap->sglen);
-
 		processed += iauth_len;
 
+		/* page_limit: number of sg entries that fit on one page */
+		max_sg_len = min_t(u64, nx_ctx->ap->sglen,
+				nx_driver.of.max_sg_len/sizeof(struct nx_sg));
+		max_sg_len = min_t(u64, max_sg_len,
+				nx_ctx->ap->databytelen/NX_PAGE_SIZE);
+
 		do {
 			to_process = min_t(u32, req->assoclen - processed,
 					   nx_ctx->ap->databytelen);
-			to_process = min_t(u64, to_process,
-					   NX_PAGE_SIZE * (max_sg_len - 1));
+
+			nx_insg = nx_walk_and_build(nx_ctx->in_sg,
+						    nx_ctx->ap->sglen,
+						    req->assoc, processed,
+						    &to_process);
 
 			if ((to_process + processed) < req->assoclen) {
 				NX_CPB_FDM(nx_ctx->csbcpb_aead) |=
@@ -297,10 +310,6 @@ static int generate_pat(u8                   *iv,
 					~NX_FDM_INTERMEDIATE;
 			}
 
-			nx_insg = nx_walk_and_build(nx_ctx->in_sg,
-						    nx_ctx->ap->sglen,
-						    req->assoc, processed,
-						    to_process);
 
 			nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_insg) *
 						sizeof(struct nx_sg);
@@ -343,7 +352,6 @@ static int ccm_nx_decrypt(struct aead_request   *req,
 	struct nx_ccm_priv *priv = &nx_ctx->priv.ccm;
 	unsigned long irq_flags;
 	unsigned int processed = 0, to_process;
-	u32 max_sg_len;
 	int rc = -1;
 
 	spin_lock_irqsave(&nx_ctx->lock, irq_flags);
@@ -360,19 +368,12 @@ static int ccm_nx_decrypt(struct aead_request   *req,
 	if (rc)
 		goto out;
 
-	/* page_limit: number of sg entries that fit on one page */
-	max_sg_len = min_t(u32, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
-			   nx_ctx->ap->sglen);
-
 	do {
 
 		/* to_process: the AES_BLOCK_SIZE data chunk to process in this
 		 * update. This value is bound by sg list limits.
 		 */
-		to_process = min_t(u64, nbytes - processed,
-				   nx_ctx->ap->databytelen);
-		to_process = min_t(u64, to_process,
-				   NX_PAGE_SIZE * (max_sg_len - 1));
+		to_process = nbytes - processed;
 
 		if ((to_process + processed) < nbytes)
 			NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
@@ -382,7 +383,7 @@ static int ccm_nx_decrypt(struct aead_request   *req,
 		NX_CPB_FDM(nx_ctx->csbcpb) &= ~NX_FDM_ENDE_ENCRYPT;
 
 		rc = nx_build_sg_lists(nx_ctx, desc, req->dst, req->src,
-					to_process, processed,
+					&to_process, processed,
 					csbcpb->cpb.aes_ccm.iv_or_ctr);
 		if (rc)
 			goto out;
@@ -427,7 +428,6 @@ static int ccm_nx_encrypt(struct aead_request   *req,
 	unsigned int authsize = crypto_aead_authsize(crypto_aead_reqtfm(req));
 	unsigned long irq_flags;
 	unsigned int processed = 0, to_process;
-	u32 max_sg_len;
 	int rc = -1;
 
 	spin_lock_irqsave(&nx_ctx->lock, irq_flags);
@@ -437,18 +437,11 @@ static int ccm_nx_encrypt(struct aead_request   *req,
 	if (rc)
 		goto out;
 
-	/* page_limit: number of sg entries that fit on one page */
-	max_sg_len = min_t(u32, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
-			   nx_ctx->ap->sglen);
-
 	do {
 		/* to process: the AES_BLOCK_SIZE data chunk to process in this
 		 * update. This value is bound by sg list limits.
 		 */
-		to_process = min_t(u64, nbytes - processed,
-				   nx_ctx->ap->databytelen);
-		to_process = min_t(u64, to_process,
-				   NX_PAGE_SIZE * (max_sg_len - 1));
+		to_process = nbytes - processed;
 
 		if ((to_process + processed) < nbytes)
 			NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
@@ -458,7 +451,7 @@ static int ccm_nx_encrypt(struct aead_request   *req,
 		NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
 
 		rc = nx_build_sg_lists(nx_ctx, desc, req->dst, req->src,
-					to_process, processed,
+					&to_process, processed,
 				       csbcpb->cpb.aes_ccm.iv_or_ctr);
 		if (rc)
 			goto out;