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: <sta...@vger.kernel.org> # 3.14.x-
Reported-by: Ben Hutchings <b...@decadent.org.uk>
Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
 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 3d9acc5..60fc0fa 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 b5ad728..8f36af6 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;

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