From: Behan Webster <beh...@converseincode.com>

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: Behan Webster <beh...@converseincode.com>
Signed-off-by: Mark Charlebois <charl...@gmail.com>
Signed-off-by: Jan-Simon Möller <dl...@gmx.de>
---
 drivers/crypto/n2_core.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/n2_core.c b/drivers/crypto/n2_core.c
index 7263c10..ed142d1 100644
--- a/drivers/crypto/n2_core.c
+++ b/drivers/crypto/n2_core.c
@@ -445,10 +445,9 @@ static int n2_hmac_async_setkey(struct crypto_ahash *tfm, 
const u8 *key,
        struct n2_hmac_ctx *ctx = crypto_ahash_ctx(tfm);
        struct crypto_shash *child_shash = ctx->child_shash;
        struct crypto_ahash *fallback_tfm;
-       struct {
-               struct shash_desc shash;
-               char ctx[crypto_shash_descsize(child_shash)];
-       } desc;
+       char desc[sizeof(struct shash_desc) +
+               crypto_shash_descsize(child_shash)] CRYPTO_MINALIGN_ATTR;
+       struct shash_desc *shash = (struct shash_desc *)desc;
        int err, bs, ds;
 
        fallback_tfm = ctx->base.fallback_tfm;
@@ -456,15 +455,15 @@ static int n2_hmac_async_setkey(struct crypto_ahash *tfm, 
const u8 *key,
        if (err)
                return err;
 
-       desc.shash.tfm = child_shash;
-       desc.shash.flags = crypto_ahash_get_flags(tfm) &
+       shash->tfm = child_shash;
+       shash->flags = crypto_ahash_get_flags(tfm) &
                CRYPTO_TFM_REQ_MAY_SLEEP;
 
        bs = crypto_shash_blocksize(child_shash);
        ds = crypto_shash_digestsize(child_shash);
        BUG_ON(ds > N2_HASH_KEY_MAX);
        if (keylen > bs) {
-               err = crypto_shash_digest(&desc.shash, key, keylen,
+               err = crypto_shash_digest(shash, key, keylen,
                                          ctx->hash_key);
                if (err)
                        return err;
-- 
1.9.1

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