[PATCH 04/12] crypto: inside-secure - move the digest to the request context

[Antoine Tenart]

This patches moves the digest information from the transformation
context to the request context. This fixes cases where HMAC init
functions were called and override the digest value for a short period
of time, as the HMAC init functions call the SHA init one which reset
the value. This lead to a small percentage of HMAC being incorrectly
computed under heavy load.

Fixes: 1b44c5a60c13 ("crypto: inside-secure - add SafeXcel EIP197 crypto engine driver")
Suggested-by: Ofer Heifetz <oferh@xxxxxxxxxxx>
Signed-off-by: Antoine Tenart <antoine.tenart@xxxxxxxxxxx>
[Ofer here did all the work, from seeing the issue to understanding the
root cause. I only made the patch.]
---
 drivers/crypto/inside-secure/safexcel_hash.c | 30 +++++++++++++++++-----------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
index 77268c9f1620..bb2be12a8f4a 100644
--- a/drivers/crypto/inside-secure/safexcel_hash.c
+++ b/drivers/crypto/inside-secure/safexcel_hash.c
@@ -21,7 +21,6 @@ struct safexcel_ahash_ctx {
 	struct safexcel_crypto_priv *priv;
 
 	u32 alg;
-	u32 digest;
 
 	u32 ipad[SHA1_DIGEST_SIZE / sizeof(u32)];
 	u32 opad[SHA1_DIGEST_SIZE / sizeof(u32)];
@@ -36,6 +35,8 @@ struct safexcel_ahash_req {
 	int nents;
 	dma_addr_t result_dma;
 
+	u32 digest;
+
 	u8 state_sz;    /* expected sate size, only set once */
 	u32 state[SHA256_DIGEST_SIZE / sizeof(u32)] __aligned(sizeof(u32));
 
@@ -53,6 +54,8 @@ struct safexcel_ahash_export_state {
 	u64 len;
 	u64 processed;
 
+	u32 digest;
+
 	u32 state[SHA256_DIGEST_SIZE / sizeof(u32)];
 	u8 cache[SHA256_BLOCK_SIZE];
 };
@@ -86,9 +89,9 @@ static void safexcel_context_control(struct safexcel_ahash_ctx *ctx,
 
 	cdesc->control_data.control0 |= CONTEXT_CONTROL_TYPE_HASH_OUT;
 	cdesc->control_data.control0 |= ctx->alg;
-	cdesc->control_data.control0 |= ctx->digest;
+	cdesc->control_data.control0 |= req->digest;
 
-	if (ctx->digest == CONTEXT_CONTROL_DIGEST_PRECOMPUTED) {
+	if (req->digest == CONTEXT_CONTROL_DIGEST_PRECOMPUTED) {
 		if (req->processed) {
 			if (ctx->alg == CONTEXT_CONTROL_CRYPTO_ALG_SHA1)
 				cdesc->control_data.control0 |= CONTEXT_CONTROL_SIZE(6);
@@ -116,7 +119,7 @@ static void safexcel_context_control(struct safexcel_ahash_ctx *ctx,
 			if (req->finish)
 				ctx->base.ctxr->data[i] = cpu_to_le32(req->processed / blocksize);
 		}
-	} else if (ctx->digest == CONTEXT_CONTROL_DIGEST_HMAC) {
+	} else if (req->digest == CONTEXT_CONTROL_DIGEST_HMAC) {
 		cdesc->control_data.control0 |= CONTEXT_CONTROL_SIZE(10);
 
 		memcpy(ctx->base.ctxr->data, ctx->ipad, digestsize);
@@ -553,7 +556,7 @@ static int safexcel_ahash_enqueue(struct ahash_request *areq)
 	if (ctx->base.ctxr) {
 		if (priv->version == EIP197 &&
 		    !ctx->base.needs_inv && req->processed &&
-		    ctx->digest == CONTEXT_CONTROL_DIGEST_PRECOMPUTED)
+		    req->digest == CONTEXT_CONTROL_DIGEST_PRECOMPUTED)
 			/* We're still setting needs_inv here, even though it is
 			 * cleared right away, because the needs_inv flag can be
 			 * set in other functions and we want to keep the same
@@ -588,7 +591,6 @@ static int safexcel_ahash_enqueue(struct ahash_request *areq)
 
 static int safexcel_ahash_update(struct ahash_request *areq)
 {
-	struct safexcel_ahash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(areq));
 	struct safexcel_ahash_req *req = ahash_request_ctx(areq);
 	struct crypto_ahash *ahash = crypto_ahash_reqtfm(areq);
 
@@ -604,7 +606,7 @@ static int safexcel_ahash_update(struct ahash_request *areq)
 	 * We're not doing partial updates when performing an hmac request.
 	 * Everything will be handled by the final() call.
 	 */
-	if (ctx->digest == CONTEXT_CONTROL_DIGEST_HMAC)
+	if (req->digest == CONTEXT_CONTROL_DIGEST_HMAC)
 		return 0;
 
 	if (req->hmac)
@@ -663,6 +665,8 @@ static int safexcel_ahash_export(struct ahash_request *areq, void *out)
 	export->len = req->len;
 	export->processed = req->processed;
 
+	export->digest = req->digest;
+
 	memcpy(export->state, req->state, req->state_sz);
 	memcpy(export->cache, req->cache, crypto_ahash_blocksize(ahash));
 
@@ -683,6 +687,8 @@ static int safexcel_ahash_import(struct ahash_request *areq, const void *in)
 	req->len = export->len;
 	req->processed = export->processed;
 
+	req->digest = export->digest;
+
 	memcpy(req->cache, export->cache, crypto_ahash_blocksize(ahash));
 	memcpy(req->state, export->state, req->state_sz);
 
@@ -719,7 +725,7 @@ static int safexcel_sha1_init(struct ahash_request *areq)
 	req->state[4] = SHA1_H4;
 
 	ctx->alg = CONTEXT_CONTROL_CRYPTO_ALG_SHA1;
-	ctx->digest = CONTEXT_CONTROL_DIGEST_PRECOMPUTED;
+	req->digest = CONTEXT_CONTROL_DIGEST_PRECOMPUTED;
 	req->state_sz = SHA1_DIGEST_SIZE;
 
 	return 0;
@@ -786,10 +792,10 @@ struct safexcel_alg_template safexcel_alg_sha1 = {
 
 static int safexcel_hmac_sha1_init(struct ahash_request *areq)
 {
-	struct safexcel_ahash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(areq));
+	struct safexcel_ahash_req *req = ahash_request_ctx(areq);
 
 	safexcel_sha1_init(areq);
-	ctx->digest = CONTEXT_CONTROL_DIGEST_HMAC;
+	req->digest = CONTEXT_CONTROL_DIGEST_HMAC;
 	return 0;
 }
 
@@ -1027,7 +1033,7 @@ static int safexcel_sha256_init(struct ahash_request *areq)
 	req->state[7] = SHA256_H7;
 
 	ctx->alg = CONTEXT_CONTROL_CRYPTO_ALG_SHA256;
-	ctx->digest = CONTEXT_CONTROL_DIGEST_PRECOMPUTED;
+	req->digest = CONTEXT_CONTROL_DIGEST_PRECOMPUTED;
 	req->state_sz = SHA256_DIGEST_SIZE;
 
 	return 0;
@@ -1089,7 +1095,7 @@ static int safexcel_sha224_init(struct ahash_request *areq)
 	req->state[7] = SHA224_H7;
 
 	ctx->alg = CONTEXT_CONTROL_CRYPTO_ALG_SHA224;
-	ctx->digest = CONTEXT_CONTROL_DIGEST_PRECOMPUTED;
+	req->digest = CONTEXT_CONTROL_DIGEST_PRECOMPUTED;
 	req->state_sz = SHA256_DIGEST_SIZE;
 
 	return 0;
-- 
2.14.3