[PATCH 3.19.y-ckt 39/66] crypto: ccp - Prevent information leakage on export

From: Kamal Mostafa
Date: Tue Apr 26 2016 - 16:33:33 EST


3.19.8-ckt20 -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 5c93afb..f10b499 100644
--- a/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
+++ b/drivers/crypto/ccp/ccp-crypto-aes-cmac.c
@@ -206,6 +206,9 @@ 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 b368e98..ced9f38 100644
--- a/drivers/crypto/ccp/ccp-crypto-sha.c
+++ b/drivers/crypto/ccp/ccp-crypto-sha.c
@@ -198,6 +198,9 @@ 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