linux-kernel - [PATCH 3.16 027/114] crypto: ccp - Prevent information leakage on export

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Message-ID: <lsq.1465842997.436706848@decadent.org.uk>
Date:	Mon, 13 Jun 2016 19:36:37 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org,
	"Tom Lendacky" <thomas.lendacky@....com>,
	"Herbert Xu" <herbert@...dor.apana.org.au>
Subject: [PATCH 3.16 027/114] crypto: ccp - Prevent information leakage on
 export

3.16.36-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Tom Lendacky <thomas.lendacky@....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@...adent.org.uk>
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 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
@@ -206,6 +206,9 @@ 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
@@ -198,6 +198,9 @@ 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;