[PATCH 4.2.y-ckt 56/93] crypto: ccp - Prevent information leakage on export

[Kamal Mostafa]

4.2.8-ckt9 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Tom Lendacky <thomas.lendacky@xxxxxxx>

commit f709b45ec461b548c41a00044dba1f1b572783bf upstream.

Prevent information from leaking to userspace by doing a memset to 0 of
the export state structure before setting the structure values and copying
it. This prevents un-initialized padding areas from being copied into the
export area.

Reported-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/crypto/ccp/ccp-crypto-aes-cmac.c | 3 +++
 drivers/crypto/ccp/ccp-crypto-sha.c      | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/crypto/ccp/ccp-crypto-aes-cmac.c b/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
index 0a4973b..a2ca3c7 100644
--- a/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
+++ b/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
@@ -207,6 +207,9 @@ 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_exp_ctx state;
 
+	/* Don't let anything leak to 'out' */
+	memset(&state, 0, sizeof(state));
+
 	state.null_msg = rctx->null_msg;
 	memcpy(state.iv, rctx->iv, sizeof(state.iv));
 	state.buf_count = rctx->buf_count;
diff --git a/drivers/crypto/ccp/ccp-crypto-sha.c b/drivers/crypto/ccp/ccp-crypto-sha.c
index 9711b6d..895c0d1 100644
--- a/drivers/crypto/ccp/ccp-crypto-sha.c
+++ b/drivers/crypto/ccp/ccp-crypto-sha.c
@@ -199,6 +199,9 @@ static int ccp_sha_export(struct ahash_request *req, void *out)
 	struct ccp_sha_req_ctx *rctx = ahash_request_ctx(req);
 	struct ccp_sha_exp_ctx state;
 
+	/* Don't let anything leak to 'out' */
+	memset(&state, 0, sizeof(state));
+
 	state.type = rctx->type;
 	state.msg_bits = rctx->msg_bits;
 	state.first = rctx->first;
-- 
2.7.4