crypto: ccp - Prevent information leakage on export

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.

Cc: <stable@vger.kernel.org> # 3.14.x-
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 6 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/ccp-crypto-aes-cmac.c b/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
index 3d9acc53d247..60fc0fa26fd3 100644
--- a/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
+++ b/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
@@ -225,6 +225,9 @@ 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 b5ad72897dc2..8f36af62fe95 100644
--- a/drivers/crypto/ccp/ccp-crypto-sha.c
+++ b/drivers/crypto/ccp/ccp-crypto-sha.c
@@ -212,6 +212,9 @@ 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;