[PATCH v4 08/12] crypto, dm: LLVMLinux: Remove VLAIS usage from dm-crypt

[behanw]

From: Jan-Simon Möller <dl...@gmx.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 a char array using the SHASH_DESC_ON_STACK macro.

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

Signed-off-by: Jan-Simon Möller <dl...@gmx.de>
Signed-off-by: Behan Webster <beh...@converseincode.com>
Reviewed-by: Mark Charlebois <charl...@gmail.com>
Acked-by: Herbert Xu <herb...@gondor.apana.org.au>
Cc: pagee...@freemail.hu
Cc: gmazyl...@gmail.com
Cc: "David S. Miller" <da...@davemloft.net>
---
 drivers/md/dm-crypt.c | 34 ++++++++++++++--------------------
 1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index cd15e08..fc93b93 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -526,29 +526,26 @@ static int crypt_iv_lmk_one(struct crypt_config *cc, u8 
*iv,
                            u8 *data)
 {
        struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
-       struct {
-               struct shash_desc desc;
-               char ctx[crypto_shash_descsize(lmk->hash_tfm)];
-       } sdesc;
+       SHASH_DESC_ON_STACK(desc, lmk->hash_tfm);
        struct md5_state md5state;
        __le32 buf[4];
        int i, r;
 
-       sdesc.desc.tfm = lmk->hash_tfm;
-       sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+       desc->tfm = lmk->hash_tfm;
+       desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 
-       r = crypto_shash_init(&sdesc.desc);
+       r = crypto_shash_init(desc);
        if (r)
                return r;
 
        if (lmk->seed) {
-               r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
+               r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE);
                if (r)
                        return r;
        }
 
        /* Sector is always 512B, block size 16, add data of blocks 1-31 */
-       r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
+       r = crypto_shash_update(desc, data + 16, 16 * 31);
        if (r)
                return r;
 
@@ -557,12 +554,12 @@ static int crypt_iv_lmk_one(struct crypt_config *cc, u8 
*iv,
        buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 
0x80000000);
        buf[2] = cpu_to_le32(4024);
        buf[3] = 0;
-       r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
+       r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf));
        if (r)
                return r;
 
        /* No MD5 padding here */
-       r = crypto_shash_export(&sdesc.desc, &md5state);
+       r = crypto_shash_export(desc, &md5state);
        if (r)
                return r;
 
@@ -679,10 +676,7 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc,
        struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
        u64 sector = cpu_to_le64((u64)dmreq->iv_sector);
        u8 buf[TCW_WHITENING_SIZE];
-       struct {
-               struct shash_desc desc;
-               char ctx[crypto_shash_descsize(tcw->crc32_tfm)];
-       } sdesc;
+       SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
        int i, r;
 
        /* xor whitening with sector number */
@@ -691,16 +685,16 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc,
        crypto_xor(&buf[8], (u8 *)&sector, 8);
 
        /* calculate crc32 for every 32bit part and xor it */
-       sdesc.desc.tfm = tcw->crc32_tfm;
-       sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+       desc->tfm = tcw->crc32_tfm;
+       desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
        for (i = 0; i < 4; i++) {
-               r = crypto_shash_init(&sdesc.desc);
+               r = crypto_shash_init(desc);
                if (r)
                        goto out;
-               r = crypto_shash_update(&sdesc.desc, &buf[i * 4], 4);
+               r = crypto_shash_update(desc, &buf[i * 4], 4);
                if (r)
                        goto out;
-               r = crypto_shash_final(&sdesc.desc, &buf[i * 4]);
+               r = crypto_shash_final(desc, &buf[i * 4]);
                if (r)
                        goto out;
        }
-- 
1.9.1

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