[PATCH v2] crypto: LLVMLinux: Remove VLAIS usage from crypto/hmac.c

[b***@converseincode.com]

=46rom: Jan-Simon M=C3=B6ller <***@gmx.de>

The use of variable length arrays in structs (VLAIS) in the Linux Kerne=
l code
precludes the use of compilers which don't implement VLAIS (for instanc=
e the
Clang compiler). This patch instead allocates the appropriate amount of=
memory
using an char array.

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 ca=
n
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 M=C3=B6ller <***@gmx.de>
Signed-off-by: Behan Webster <***@converseincode.com>
Cc: ***@freemail.hu
---
crypto/hmac.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/crypto/hmac.c b/crypto/hmac.c
index 8d9544c..f2da806 100644
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -52,20 +52,19 @@ static int hmac_setkey(struct crypto_shash *parent,
struct hmac_ctx *ctx =3D align_ptr(opad + ss,
crypto_tfm_ctx_alignment());
struct crypto_shash *hash =3D ctx->hash;
- struct {
- struct shash_desc shash;
- char ctx[crypto_shash_descsize(hash)];
- } desc;
+ char desc[sizeof(struct shash_desc) +
+ crypto_shash_descsize(hash)] CRYPTO_MINALIGN_ATTR;
+ struct shash_desc *shash =3D (struct shash_desc *)desc;
unsigned int i;
=20
- desc.shash.tfm =3D hash;
- desc.shash.flags =3D crypto_shash_get_flags(parent) &
- CRYPTO_TFM_REQ_MAY_SLEEP;
+ shash->tfm =3D hash;
+ shash->flags =3D crypto_shash_get_flags(parent)
+ & CRYPTO_TFM_REQ_MAY_SLEEP;
=20
if (keylen > bs) {
int err;
=20
- err =3D crypto_shash_digest(&desc.shash, inkey, keylen, ipad);
+ err =3D crypto_shash_digest(shash, inkey, keylen, ipad);
if (err)
return err;
=20
@@ -81,12 +80,12 @@ static int hmac_setkey(struct crypto_shash *parent,
opad[i] ^=3D 0x5c;
}
=20
- return crypto_shash_init(&desc.shash) ?:
- crypto_shash_update(&desc.shash, ipad, bs) ?:
- crypto_shash_export(&desc.shash, ipad) ?:
- crypto_shash_init(&desc.shash) ?:
- crypto_shash_update(&desc.shash, opad, bs) ?:
- crypto_shash_export(&desc.shash, opad);
+ return crypto_shash_init(shash) ?:
+ crypto_shash_update(shash, ipad, bs) ?:
+ crypto_shash_export(shash, ipad) ?:
+ crypto_shash_init(shash) ?:
+ crypto_shash_update(shash, opad, bs) ?:
+ crypto_shash_export(shash, opad);
}
=20
static int hmac_export(struct shash_desc *pdesc, void *out)
--=20
1.9.1