[PATCH 4.5 060/200] crypto: ccp - Prevent information leakage on export

Greg Kroah-Hartman
2016-05-03T01:17:53Z

From: Tom Lendacky <thomas.lendacky@amd.com>

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@decadent.org.uk>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/crypto/ccp/ccp-crypto-aes-cmac.c | 3 +++
drivers/crypto/ccp/ccp-crypto-sha.c | 3 +++
2 files changed, 6 insertions(+)

--- 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 ah
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;
--- 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_r
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;