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>
---
 net/bluetooth/amp.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/bluetooth/amp.c b/net/bluetooth/amp.c
index 016cdb6..2640d78 100644
--- a/net/bluetooth/amp.c
+++ b/net/bluetooth/amp.c
@@ -149,15 +149,14 @@ static int hmac_sha256(u8 *key, u8 ksize, char 
*plaintext, u8 psize, u8 *output)
        if (ret) {
                BT_DBG("crypto_ahash_setkey failed: err %d", ret);
        } else {
-               struct {
-                       struct shash_desc shash;
-                       char ctx[crypto_shash_descsize(tfm)];
-               } desc;
+               char desc[sizeof(struct shash_desc) +
+                       crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR;
+               struct shash_desc *shash = (struct shash_desc *)desc;
 
-               desc.shash.tfm = tfm;
-               desc.shash.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+               shash->tfm = tfm;
+               shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
-               ret = crypto_shash_digest(&desc.shash, plaintext, psize,
+               ret = crypto_shash_digest(shash, plaintext, psize,
                                          output);
        }
 
-- 
1.9.1

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