[PATCH 3.16 012/217] crypto: ccp - Limit the amount of information exported

[Ben Hutchings]

3.16.35-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Tom Lendacky <thomas.lendacky@xxxxxxx>

commit d1662165ae612ec8b5f94a6b07e65ea58b6dce34 upstream.

Since the exported information can be exposed to user-space, instead of
exporting the entire request context only export the minimum information
needed.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/crypto/ccp/ccp-crypto-aes-cmac.c | 16 +++++++++++-----
 drivers/crypto/ccp/ccp-crypto-sha.c      | 20 +++++++++++++++-----
 drivers/crypto/ccp/ccp-crypto.h          | 22 ++++++++++++++++++++++
 3 files changed, 48 insertions(+), 10 deletions(-)

--- a/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
+++ b/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
@@ -204,9 +204,12 @@ static int ccp_aes_cmac_digest(struct ah
 static int ccp_aes_cmac_export(struct ahash_request *req, void *out)
 {
 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
-	struct ccp_aes_cmac_req_ctx *state = out;
+	struct ccp_aes_cmac_exp_ctx *state = out;
 
-	*state = *rctx;
+	state->null_msg = rctx->null_msg;
+	memcpy(state->iv, rctx->iv, sizeof(state->iv));
+	state->buf_count = rctx->buf_count;
+	memcpy(state->buf, rctx->buf, sizeof(state->buf));
 
 	return 0;
 }
@@ -214,9 +217,12 @@ static int ccp_aes_cmac_export(struct ah
 static int ccp_aes_cmac_import(struct ahash_request *req, const void *in)
 {
 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
-	const struct ccp_aes_cmac_req_ctx *state = in;
+	const struct ccp_aes_cmac_exp_ctx *state = in;
 
-	*rctx = *state;
+	rctx->null_msg = state->null_msg;
+	memcpy(rctx->iv, state->iv, sizeof(rctx->iv));
+	rctx->buf_count = state->buf_count;
+	memcpy(rctx->buf, state->buf, sizeof(rctx->buf));
 
 	return 0;
 }
@@ -358,7 +364,7 @@ int ccp_register_aes_cmac_algs(struct li
 
 	halg = &alg->halg;
 	halg->digestsize = AES_BLOCK_SIZE;
-	halg->statesize = sizeof(struct ccp_aes_cmac_req_ctx);
+	halg->statesize = sizeof(struct ccp_aes_cmac_exp_ctx);
 
 	base = &halg->base;
 	snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
--- a/drivers/crypto/ccp/ccp-crypto-sha.c
+++ b/drivers/crypto/ccp/ccp-crypto-sha.c
@@ -196,9 +196,14 @@ static int ccp_sha_digest(struct ahash_r
 static int ccp_sha_export(struct ahash_request *req, void *out)
 {
 	struct ccp_sha_req_ctx *rctx = ahash_request_ctx(req);
-	struct ccp_sha_req_ctx *state = out;
+	struct ccp_sha_exp_ctx *state = out;
 
-	*state = *rctx;
+	state->type = rctx->type;
+	state->msg_bits = rctx->msg_bits;
+	state->first = rctx->first;
+	memcpy(state->ctx, rctx->ctx, sizeof(state->ctx));
+	state->buf_count = rctx->buf_count;
+	memcpy(state->buf, rctx->buf, sizeof(state->buf));
 
 	return 0;
 }
@@ -206,9 +211,14 @@ static int ccp_sha_export(struct ahash_r
 static int ccp_sha_import(struct ahash_request *req, const void *in)
 {
 	struct ccp_sha_req_ctx *rctx = ahash_request_ctx(req);
-	const struct ccp_sha_req_ctx *state = in;
+	const struct ccp_sha_exp_ctx *state = in;
 
-	*rctx = *state;
+	rctx->type = state->type;
+	rctx->msg_bits = state->msg_bits;
+	rctx->first = state->first;
+	memcpy(rctx->ctx, state->ctx, sizeof(rctx->ctx));
+	rctx->buf_count = state->buf_count;
+	memcpy(rctx->buf, state->buf, sizeof(rctx->buf));
 
 	return 0;
 }
@@ -414,7 +424,7 @@ static int ccp_register_sha_alg(struct l
 
 	halg = &alg->halg;
 	halg->digestsize = def->digest_size;
-	halg->statesize = sizeof(struct ccp_sha_req_ctx);
+	halg->statesize = sizeof(struct ccp_sha_exp_ctx);
 
 	base = &halg->base;
 	snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
--- a/drivers/crypto/ccp/ccp-crypto.h
+++ b/drivers/crypto/ccp/ccp-crypto.h
@@ -132,6 +132,15 @@ struct ccp_aes_cmac_req_ctx {
 	struct ccp_cmd cmd;
 };
 
+struct ccp_aes_cmac_exp_ctx {
+	unsigned int null_msg;
+
+	u8 iv[AES_BLOCK_SIZE];
+
+	unsigned int buf_count;
+	u8 buf[AES_BLOCK_SIZE];
+};
+
 /***** SHA related defines *****/
 #define MAX_SHA_CONTEXT_SIZE	SHA256_DIGEST_SIZE
 #define MAX_SHA_BLOCK_SIZE	SHA256_BLOCK_SIZE
@@ -174,6 +183,19 @@ struct ccp_sha_req_ctx {
 	struct ccp_cmd cmd;
 };
 
+struct ccp_sha_exp_ctx {
+	enum ccp_sha_type type;
+
+	u64 msg_bits;
+
+	unsigned int first;
+
+	u8 ctx[MAX_SHA_CONTEXT_SIZE];
+
+	unsigned int buf_count;
+	u8 buf[MAX_SHA_BLOCK_SIZE];
+};
+
 /***** Common Context Structure *****/
 struct ccp_ctx {
 	int (*complete)(struct crypto_async_request *req, int ret);