crypto: caam - fix MDHA key derivation for certain user key lengths

Fuzz testing uncovered an issue when |user key| > |derived key|.
Derived key generation has to be fixed in two cases:

1. Era >= 6 (DKP is available)
DKP cannot be used with immediate input key if |user key| > |derived key|,
since the resulting descriptor (after DKP execution) would be invalid -
having a few bytes from user key left in descriptor buffer
as incorrect opcodes.

Fix DKP usage both in standalone hmac and in authenc algorithms.
For authenc the logic is simplified, by always storing both virtual
and dma key addresses.

2. Era < 6
The same case (|user key| > |derived key|) fails when DKP
is not available.
Make sure gen_split_key() dma maps max(|user key|, |derived key|),
since this is an in-place (bidirectional) operation.

Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Reviewed-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 38 insertions, 15 deletions

diff --git a/drivers/crypto/caam/caamhash.c b/drivers/crypto/caam/caamhash.c
index d19373e6ed4a..ed1931f97df1 100644
--- a/drivers/crypto/caam/caamhash.c
+++ b/drivers/crypto/caam/caamhash.c
@@ -96,6 +96,7 @@ struct caam_hash_ctx {
 	dma_addr_t sh_desc_fin_dma;
 	dma_addr_t sh_desc_digest_dma;
 	enum dma_data_direction dir;
+	enum dma_data_direction key_dir;
 	struct device *jrdev;
 	int ctx_len;
 	struct alginfo adata;
@@ -476,6 +477,18 @@ static int ahash_setkey(struct crypto_ahash *ahash,
 			goto bad_free_key;
 
 		memcpy(ctx->key, key, keylen);
+
+		/*
+		 * In case |user key| > |derived key|, using DKP<imm,imm>
+		 * would result in invalid opcodes (last bytes of user key) in
+		 * the resulting descriptor. Use DKP<ptr,imm> instead => both
+		 * virtual and dma key addresses are needed.
+		 */
+		if (keylen > ctx->adata.keylen_pad)
+			dma_sync_single_for_device(ctx->jrdev,
+						   ctx->adata.key_dma,
+						   ctx->adata.keylen_pad,
+						   DMA_TO_DEVICE);
 	} else {
 		ret = gen_split_key(ctx->jrdev, ctx->key, &ctx->adata, key,
 				    keylen, CAAM_MAX_HASH_KEY_SIZE);
@@ -1825,40 +1838,50 @@ static int caam_hash_cra_init(struct crypto_tfm *tfm)
 
 	if (is_xcbc_aes(caam_hash->alg_type)) {
 		ctx->dir = DMA_TO_DEVICE;
+		ctx->key_dir = DMA_BIDIRECTIONAL;
 		ctx->adata.algtype = OP_TYPE_CLASS1_ALG | caam_hash->alg_type;
 		ctx->ctx_len = 48;
-
-		ctx->adata.key_dma = dma_map_single_attrs(ctx->jrdev, ctx->key,
-							  ARRAY_SIZE(ctx->key),
-							  DMA_BIDIRECTIONAL,
-							  DMA_ATTR_SKIP_CPU_SYNC);
-		if (dma_mapping_error(ctx->jrdev, ctx->adata.key_dma)) {
-			dev_err(ctx->jrdev, "unable to map key\n");
-			caam_jr_free(ctx->jrdev);
-			return -ENOMEM;
-		}
 	} else if (is_cmac_aes(caam_hash->alg_type)) {
 		ctx->dir = DMA_TO_DEVICE;
+		ctx->key_dir = DMA_NONE;
 		ctx->adata.algtype = OP_TYPE_CLASS1_ALG | caam_hash->alg_type;
 		ctx->ctx_len = 32;
 	} else {
-		ctx->dir = priv->era >= 6 ? DMA_BIDIRECTIONAL : DMA_TO_DEVICE;
+		if (priv->era >= 6) {
+			ctx->dir = DMA_BIDIRECTIONAL;
+			ctx->key_dir = alg->setkey ? DMA_TO_DEVICE : DMA_NONE;
+		} else {
+			ctx->dir = DMA_TO_DEVICE;
+			ctx->key_dir = DMA_NONE;
+		}
 		ctx->adata.algtype = OP_TYPE_CLASS2_ALG | caam_hash->alg_type;
 		ctx->ctx_len = runninglen[(ctx->adata.algtype &
 					   OP_ALG_ALGSEL_SUBMASK) >>
 					  OP_ALG_ALGSEL_SHIFT];
 	}
 
+	if (ctx->key_dir != DMA_NONE) {
+		ctx->adata.key_dma = dma_map_single_attrs(ctx->jrdev, ctx->key,
+							  ARRAY_SIZE(ctx->key),
+							  ctx->key_dir,
+							  DMA_ATTR_SKIP_CPU_SYNC);
+		if (dma_mapping_error(ctx->jrdev, ctx->adata.key_dma)) {
+			dev_err(ctx->jrdev, "unable to map key\n");
+			caam_jr_free(ctx->jrdev);
+			return -ENOMEM;
+		}
+	}
+
 	dma_addr = dma_map_single_attrs(ctx->jrdev, ctx->sh_desc_update,
 					offsetof(struct caam_hash_ctx, key),
 					ctx->dir, DMA_ATTR_SKIP_CPU_SYNC);
 	if (dma_mapping_error(ctx->jrdev, dma_addr)) {
 		dev_err(ctx->jrdev, "unable to map shared descriptors\n");
 
-		if (is_xcbc_aes(caam_hash->alg_type))
+		if (ctx->key_dir != DMA_NONE)
 			dma_unmap_single_attrs(ctx->jrdev, ctx->adata.key_dma,
 					       ARRAY_SIZE(ctx->key),
-					       DMA_BIDIRECTIONAL,
+					       ctx->key_dir,
 					       DMA_ATTR_SKIP_CPU_SYNC);
 
 		caam_jr_free(ctx->jrdev);
@@ -1891,9 +1914,9 @@ static void caam_hash_cra_exit(struct crypto_tfm *tfm)
 	dma_unmap_single_attrs(ctx->jrdev, ctx->sh_desc_update_dma,
 			       offsetof(struct caam_hash_ctx, key),
 			       ctx->dir, DMA_ATTR_SKIP_CPU_SYNC);
-	if (is_xcbc_aes(ctx->adata.algtype))
+	if (ctx->key_dir != DMA_NONE)
 		dma_unmap_single_attrs(ctx->jrdev, ctx->adata.key_dma,
-				       ARRAY_SIZE(ctx->key), DMA_BIDIRECTIONAL,
+				       ARRAY_SIZE(ctx->key), ctx->key_dir,
 				       DMA_ATTR_SKIP_CPU_SYNC);
 	caam_jr_free(ctx->jrdev);
 }