linux-kernel - [PATCH] crypto: LLVMLinux: Remove VLAIS from crypto/ccp/ccp-crypto-sha.c

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Date:	Fri,  5 Sep 2014 15:59:04 -0700
From:	behanw@...verseincode.com
To:	davem@...emloft.net, herbert@...dor.apana.org.au
Cc:	linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
	thomas.lendacky@....com,
	Jan-Simon Möller <dl9pf@....de>,
	Behan Webster <behanw@...verseincode.com>
Subject: [PATCH] crypto: LLVMLinux: Remove VLAIS from crypto/ccp/ccp-crypto-sha.c

From: Jan-Simon Möller <dl9pf@....de>

Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
compliant equivalent. This patch allocates the appropriate amount of memory
using an char array.

The new code can be compiled with both gcc and clang.

struct shash_desc contains a flexible array member member ctx declared with
CRYPTO_MINALIGN_ATTR, so sizeof(struct shash_desc) aligns the beginning
of the array declared after struct shash_desc with long long.

No trailing padding is required because it is not a struct type that can
be used in an array.

The CRYPTO_MINALIGN_ATTR is required so that desc is aligned with long long
as would be the case for a struct containing a member with
CRYPTO_MINALIGN_ATTR.

Signed-off-by: Jan-Simon Möller <dl9pf@....de>
Signed-off-by: Behan Webster <behanw@...verseincode.com>
---
 drivers/crypto/ccp/ccp-crypto-sha.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/ccp/ccp-crypto-sha.c b/drivers/crypto/ccp/ccp-crypto-sha.c
index 873f234..29f9fda 100644
--- a/drivers/crypto/ccp/ccp-crypto-sha.c
+++ b/drivers/crypto/ccp/ccp-crypto-sha.c
@@ -198,10 +198,11 @@ static int ccp_sha_setkey(struct crypto_ahash *tfm, const u8 *key,
 {
 	struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
 	struct crypto_shash *shash = ctx->u.sha.hmac_tfm;
-	struct {
-		struct shash_desc sdesc;
-		char ctx[crypto_shash_descsize(shash)];
-	} desc;
+
+	char desc[sizeof(struct shash_desc) +
+		crypto_shash_descsize(shash)] CRYPTO_MINALIGN_ATTR;
+	struct shash_desc *sdesc = (struct shash_desc *)desc;
+
 	unsigned int block_size = crypto_shash_blocksize(shash);
 	unsigned int digest_size = crypto_shash_digestsize(shash);
 	int i, ret;
@@ -216,11 +217,11 @@ static int ccp_sha_setkey(struct crypto_ahash *tfm, const u8 *key,
 
 	if (key_len > block_size) {
 		/* Must hash the input key */
-		desc.sdesc.tfm = shash;
-		desc.sdesc.flags = crypto_ahash_get_flags(tfm) &
+		sdesc->tfm = shash;
+		sdesc->flags = crypto_ahash_get_flags(tfm) &
 			CRYPTO_TFM_REQ_MAY_SLEEP;
 
-		ret = crypto_shash_digest(&desc.sdesc, key, key_len,
+		ret = crypto_shash_digest(sdesc, key, key_len,
 					  ctx->u.sha.key);
 		if (ret) {
 			crypto_ahash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
-- 
1.9.1

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