[PATCH v3 00/12] LLVMLinux: Patches to enable the kernel to be compiled with clang/LLVM

[PATCH v3 00/12] LLVMLinux: Patches to enable the kernel to be compiled with clang/LLVM

[behanw]

From: Behan Webster <behanw@converseincode.com>

These patches replace the use of Variable Length Arrays In Structs (VLAIS) in
crypto related code with C99 compliant equivalent code. A SHASH_DESC_ON_STACK()
macro is added to hash.h which is then used to replace the use of VLAIS in all
the other patches. The minimum size and alignment are maintained by the new code.

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

The LLVMLinux project aims to fully build the Linux kernel using both gcc and
clang (the C front end for the LLVM compiler infrastructure project). 

Behan Webster (6):
  crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code
  crypto: LLVMLinux: Remove VLAIS from crypto/mv_cesa.c
  crypto: LLVMLinux: Remove VLAIS from crypto/n2_core.c
  crypto: LLVMLinux: Remove VLAIS from crypto/omap_sham.c
  crypto: LLVMLinux: Remove VLAIS from crypto/.../qat_algs.c
  security, crypto: LLVMLinux: Remove VLAIS from ima_crypto.c

Jan-Simon Möller (5):
  crypto: LLVMLinux: Remove VLAIS from crypto/ccp/ccp-crypto-sha.c
  crypto, dm: LLVMLinux: Remove VLAIS usage from dm-crypt
  crypto: LLVMLinux: Remove VLAIS usage from crypto/hmac.c
  crypto: LLVMLinux: Remove VLAIS usage from libcrc32c.c
  crypto: LLVMLinux: Remove VLAIS usage from crypto/testmgr.c

Vinícius Tinti (1):
  btrfs: LLVMLinux: Remove VLAIS

 crypto/hmac.c                            | 25 +++++++---------
 crypto/testmgr.c                         | 14 ++++-----
 drivers/crypto/ccp/ccp-crypto-sha.c      | 13 ++++----
 drivers/crypto/mv_cesa.c                 | 41 +++++++++++--------------
 drivers/crypto/n2_core.c                 | 11 +++----
 drivers/crypto/omap-sham.c               | 28 +++++++-----------
 drivers/crypto/qat/qat_common/qat_algs.c | 31 +++++++++----------
 drivers/md/dm-crypt.c                    | 34 +++++++++------------
 fs/btrfs/hash.c                          | 16 +++++-----
 include/crypto/hash.h                    |  5 ++++
 lib/libcrc32c.c                          | 16 +++++-----
 security/integrity/ima/ima_crypto.c      | 51 ++++++++++++++------------------
 12 files changed, 126 insertions(+), 159 deletions(-)

-- 
1.9.1

[PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

[behanw]

From: Behan Webster <behanw@converseincode.com>

Add a macro which replaces the use of a Variable Length Array In Struct (VLAIS)
with a C99 compliant equivalent. This macro instead 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 <behanw@converseincode.com>
---
 include/crypto/hash.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index a391955..541125b 100644
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -58,6 +58,11 @@ struct shash_desc {
 	void *__ctx[] CRYPTO_MINALIGN_ATTR;
 };
 
+#define SHASH_DESC_ON_STACK(shash, tfm)				  \
+	char __desc[sizeof(struct shash_desc) +                   \
+		crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR; \
+	struct shash_desc *shash = (struct shash_desc *)__desc
+
 struct shash_alg {
 	int (*init)(struct shash_desc *desc);
 	int (*update)(struct shash_desc *desc, const u8 *data,
-- 
1.9.1

[PATCH v3 02/12] btrfs: LLVMLinux: Remove VLAIS

[behanw]

From: Vinícius Tinti <viniciustinti@gmail.com>

Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
compliant equivalent. This is the original VLAIS struct.

struct {
	struct shash_desc shash;
	char ctx[crypto_shash_descsize(tfm)];
} desc;

This patch instead 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: Vinícius Tinti <viniciustinti@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
---
 fs/btrfs/hash.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
index 85889aa..4bf4d3a 100644
--- a/fs/btrfs/hash.c
+++ b/fs/btrfs/hash.c
@@ -33,18 +33,16 @@ void btrfs_hash_exit(void)
 
 u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length)
 {
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(tfm)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, tfm);
+	u32 *ctx = (u32 *)shash_desc_ctx(shash);
 	int err;
 
-	desc.shash.tfm = tfm;
-	desc.shash.flags = 0;
-	*(u32 *)desc.ctx = crc;
+	shash->tfm = tfm;
+	shash->flags = 0;
+	*ctx = crc;
 
-	err = crypto_shash_update(&desc.shash, address, length);
+	err = crypto_shash_update(shash, address, length);
 	BUG_ON(err);
 
-	return *(u32 *)desc.ctx;
+	return *ctx;
 }
-- 
1.9.1

[PATCH v3 03/12] crypto: LLVMLinux: Remove VLAIS from crypto/ccp/ccp-crypto-sha.c

[behanw]

From: Jan-Simon Möller <dl9pf@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 <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
---
 drivers/crypto/ccp/ccp-crypto-sha.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/ccp/ccp-crypto-sha.c b/drivers/crypto/ccp/ccp-crypto-sha.c
index 873f234..9653157 100644
--- a/drivers/crypto/ccp/ccp-crypto-sha.c
+++ b/drivers/crypto/ccp/ccp-crypto-sha.c
@@ -198,10 +198,9 @@ 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;
+
+	SHASH_DESC_ON_STACK(sdesc, shash);
+
 	unsigned int block_size = crypto_shash_blocksize(shash);
 	unsigned int digest_size = crypto_shash_digestsize(shash);
 	int i, ret;
@@ -216,11 +215,11 @@ 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

[PATCH v3 04/12] crypto: LLVMLinux: Remove VLAIS from crypto/mv_cesa.c

[behanw]

From: Behan Webster <behanw@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 a char array using the SHASH_DESC_ON_STACK macro.

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

Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
---
 drivers/crypto/mv_cesa.c | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/drivers/crypto/mv_cesa.c b/drivers/crypto/mv_cesa.c
index 29d0ee5..032c72c 100644
--- a/drivers/crypto/mv_cesa.c
+++ b/drivers/crypto/mv_cesa.c
@@ -402,26 +402,23 @@ static int mv_hash_final_fallback(struct ahash_request *req)
 {
 	const struct mv_tfm_hash_ctx *tfm_ctx = crypto_tfm_ctx(req->base.tfm);
 	struct mv_req_hash_ctx *req_ctx = ahash_request_ctx(req);
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(tfm_ctx->fallback)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, tfm_ctx->fallback);
 	int rc;
 
-	desc.shash.tfm = tfm_ctx->fallback;
-	desc.shash.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+	shash->tfm = tfm_ctx->fallback;
+	shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 	if (unlikely(req_ctx->first_hash)) {
-		crypto_shash_init(&desc.shash);
-		crypto_shash_update(&desc.shash, req_ctx->buffer,
+		crypto_shash_init(shash);
+		crypto_shash_update(shash, req_ctx->buffer,
 				    req_ctx->extra_bytes);
 	} else {
 		/* only SHA1 for now....
 		 */
-		rc = mv_hash_import_sha1_ctx(req_ctx, &desc.shash);
+		rc = mv_hash_import_sha1_ctx(req_ctx, shash);
 		if (rc)
 			goto out;
 	}
-	rc = crypto_shash_final(&desc.shash, req->result);
+	rc = crypto_shash_final(shash, req->result);
 out:
 	return rc;
 }
@@ -794,23 +791,21 @@ static int mv_hash_setkey(struct crypto_ahash *tfm, const u8 * key,
 	ss = crypto_shash_statesize(ctx->base_hash);
 
 	{
-		struct {
-			struct shash_desc shash;
-			char ctx[crypto_shash_descsize(ctx->base_hash)];
-		} desc;
+		SHASH_DESC_ON_STACK(shash, ctx->base_hash);
+
 		unsigned int i;
 		char ipad[ss];
 		char opad[ss];
 
-		desc.shash.tfm = ctx->base_hash;
-		desc.shash.flags = crypto_shash_get_flags(ctx->base_hash) &
+		shash->tfm = ctx->base_hash;
+		shash->flags = crypto_shash_get_flags(ctx->base_hash) &
 		    CRYPTO_TFM_REQ_MAY_SLEEP;
 
 		if (keylen > bs) {
 			int err;
 
 			err =
-			    crypto_shash_digest(&desc.shash, key, keylen, ipad);
+			    crypto_shash_digest(shash, key, keylen, ipad);
 			if (err)
 				return err;
 
@@ -826,12 +821,12 @@ static int mv_hash_setkey(struct crypto_ahash *tfm, const u8 * key,
 			opad[i] ^= 0x5c;
 		}
 
-		rc = 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);
+		rc = 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);
 
 		if (rc == 0)
 			mv_hash_init_ivs(ctx, ipad, opad);
-- 
1.9.1

[PATCH v3 05/12] crypto: LLVMLinux: Remove VLAIS from crypto/n2_core.c

[behanw]

From: Behan Webster <behanw@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 a char array using the SHASH_DESC_ON_STACK macro.

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

Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
---
 drivers/crypto/n2_core.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/n2_core.c b/drivers/crypto/n2_core.c
index 7263c10..f8e3207 100644
--- a/drivers/crypto/n2_core.c
+++ b/drivers/crypto/n2_core.c
@@ -445,10 +445,7 @@ 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;
+	SHASH_DESC_ON_STACK(shash, child_shash);
 	int err, bs, ds;
 
 	fallback_tfm = ctx->base.fallback_tfm;
@@ -456,15 +453,15 @@ 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

[PATCH v3 06/12] crypto: LLVMLinux: Remove VLAIS from crypto/omap_sham.c

[behanw]

From: Behan Webster <behanw@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 a char array using the SHASH_DESC_ON_STACK macro.

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

Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
---
 drivers/crypto/omap-sham.c | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c
index 710d863..24ef489 100644
--- a/drivers/crypto/omap-sham.c
+++ b/drivers/crypto/omap-sham.c
@@ -949,17 +949,14 @@ static int omap_sham_finish_hmac(struct ahash_request *req)
 	struct omap_sham_hmac_ctx *bctx = tctx->base;
 	int bs = crypto_shash_blocksize(bctx->shash);
 	int ds = crypto_shash_digestsize(bctx->shash);
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(bctx->shash)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, bctx->shash);
 
-	desc.shash.tfm = bctx->shash;
-	desc.shash.flags = 0; /* not CRYPTO_TFM_REQ_MAY_SLEEP */
+	shash->tfm = bctx->shash;
+	shash->flags = 0; /* not CRYPTO_TFM_REQ_MAY_SLEEP */
 
-	return crypto_shash_init(&desc.shash) ?:
-	       crypto_shash_update(&desc.shash, bctx->opad, bs) ?:
-	       crypto_shash_finup(&desc.shash, req->result, ds, req->result);
+	return crypto_shash_init(shash) ?:
+	       crypto_shash_update(shash, bctx->opad, bs) ?:
+	       crypto_shash_finup(shash, req->result, ds, req->result);
 }
 
 static int omap_sham_finish(struct ahash_request *req)
@@ -1118,18 +1115,15 @@ static int omap_sham_update(struct ahash_request *req)
 	return omap_sham_enqueue(req, OP_UPDATE);
 }
 
-static int omap_sham_shash_digest(struct crypto_shash *shash, u32 flags,
+static int omap_sham_shash_digest(struct crypto_shash *tfm, u32 flags,
 				  const u8 *data, unsigned int len, u8 *out)
 {
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(shash)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, tfm);
 
-	desc.shash.tfm = shash;
-	desc.shash.flags = flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+	shash->tfm = tfm;
+	shash->flags = flags & CRYPTO_TFM_REQ_MAY_SLEEP;
 
-	return crypto_shash_digest(&desc.shash, data, len, out);
+	return crypto_shash_digest(shash, data, len, out);
 }
 
 static int omap_sham_final_shash(struct ahash_request *req)
-- 
1.9.1

[PATCH v3 07/12] crypto: LLVMLinux: Remove VLAIS from crypto/.../qat_algs.c

[behanw]

From: Behan Webster <behanw@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 a char array using the SHASH_DESC_ON_STACK macro.

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

Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
---
 drivers/crypto/qat/qat_common/qat_algs.c | 31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/drivers/crypto/qat/qat_common/qat_algs.c b/drivers/crypto/qat/qat_common/qat_algs.c
index 59df488..9cabadd 100644
--- a/drivers/crypto/qat/qat_common/qat_algs.c
+++ b/drivers/crypto/qat/qat_common/qat_algs.c
@@ -152,10 +152,7 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
 				  const uint8_t *auth_key,
 				  unsigned int auth_keylen, uint8_t *auth_state)
 {
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(ctx->hash_tfm)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, ctx->hash_tfm);
 	struct sha1_state sha1;
 	struct sha256_state sha256;
 	struct sha512_state sha512;
@@ -167,12 +164,12 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
 	__be64 *hash512_state_out;
 	int i, offset;
 
-	desc.shash.tfm = ctx->hash_tfm;
-	desc.shash.flags = 0x0;
+	shash->tfm = ctx->hash_tfm;
+	shash->flags = 0x0;
 
 	if (auth_keylen > block_size) {
 		char buff[SHA512_BLOCK_SIZE];
-		int ret = crypto_shash_digest(&desc.shash, auth_key,
+		int ret = crypto_shash_digest(shash, auth_key,
 					      auth_keylen, buff);
 		if (ret)
 			return ret;
@@ -195,10 +192,10 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
 		*opad_ptr ^= 0x5C;
 	}
 
-	if (crypto_shash_init(&desc.shash))
+	if (crypto_shash_init(shash))
 		return -EFAULT;
 
-	if (crypto_shash_update(&desc.shash, ipad, block_size))
+	if (crypto_shash_update(shash, ipad, block_size))
 		return -EFAULT;
 
 	hash_state_out = (__be32 *)hash->sha.state1;
@@ -206,19 +203,19 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
 
 	switch (ctx->qat_hash_alg) {
 	case ICP_QAT_HW_AUTH_ALGO_SHA1:
-		if (crypto_shash_export(&desc.shash, &sha1))
+		if (crypto_shash_export(shash, &sha1))
 			return -EFAULT;
 		for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
 			*hash_state_out = cpu_to_be32(*(sha1.state + i));
 		break;
 	case ICP_QAT_HW_AUTH_ALGO_SHA256:
-		if (crypto_shash_export(&desc.shash, &sha256))
+		if (crypto_shash_export(shash, &sha256))
 			return -EFAULT;
 		for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
 			*hash_state_out = cpu_to_be32(*(sha256.state + i));
 		break;
 	case ICP_QAT_HW_AUTH_ALGO_SHA512:
-		if (crypto_shash_export(&desc.shash, &sha512))
+		if (crypto_shash_export(shash, &sha512))
 			return -EFAULT;
 		for (i = 0; i < digest_size >> 3; i++, hash512_state_out++)
 			*hash512_state_out = cpu_to_be64(*(sha512.state + i));
@@ -227,10 +224,10 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
 		return -EFAULT;
 	}
 
-	if (crypto_shash_init(&desc.shash))
+	if (crypto_shash_init(shash))
 		return -EFAULT;
 
-	if (crypto_shash_update(&desc.shash, opad, block_size))
+	if (crypto_shash_update(shash, opad, block_size))
 		return -EFAULT;
 
 	offset = round_up(qat_get_inter_state_size(ctx->qat_hash_alg), 8);
@@ -239,19 +236,19 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
 
 	switch (ctx->qat_hash_alg) {
 	case ICP_QAT_HW_AUTH_ALGO_SHA1:
-		if (crypto_shash_export(&desc.shash, &sha1))
+		if (crypto_shash_export(shash, &sha1))
 			return -EFAULT;
 		for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
 			*hash_state_out = cpu_to_be32(*(sha1.state + i));
 		break;
 	case ICP_QAT_HW_AUTH_ALGO_SHA256:
-		if (crypto_shash_export(&desc.shash, &sha256))
+		if (crypto_shash_export(shash, &sha256))
 			return -EFAULT;
 		for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
 			*hash_state_out = cpu_to_be32(*(sha256.state + i));
 		break;
 	case ICP_QAT_HW_AUTH_ALGO_SHA512:
-		if (crypto_shash_export(&desc.shash, &sha512))
+		if (crypto_shash_export(shash, &sha512))
 			return -EFAULT;
 		for (i = 0; i < digest_size >> 3; i++, hash512_state_out++)
 			*hash512_state_out = cpu_to_be64(*(sha512.state + i));
-- 
1.9.1

[PATCH v3 08/12] crypto, dm: LLVMLinux: Remove VLAIS usage from dm-crypt

[behanw]

From: Jan-Simon Möller <dl9pf@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 <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: pageexec@freemail.hu
Cc: gmazyland@gmail.com
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
---
 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

[PATCH v3 09/12] crypto: LLVMLinux: Remove VLAIS usage from crypto/hmac.c

[behanw]

From: Jan-Simon Möller <dl9pf@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 <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: pageexec@freemail.hu
---
 crypto/hmac.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/crypto/hmac.c b/crypto/hmac.c
index 8d9544c..e392219 100644
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -52,20 +52,17 @@ static int hmac_setkey(struct crypto_shash *parent,
 	struct hmac_ctx *ctx = align_ptr(opad + ss,
 					 crypto_tfm_ctx_alignment());
 	struct crypto_shash *hash = ctx->hash;
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(hash)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, hash);
 	unsigned int i;
 
-	desc.shash.tfm = hash;
-	desc.shash.flags = crypto_shash_get_flags(parent) &
-			    CRYPTO_TFM_REQ_MAY_SLEEP;
+	shash->tfm = hash;
+	shash->flags = crypto_shash_get_flags(parent)
+		& CRYPTO_TFM_REQ_MAY_SLEEP;
 
 	if (keylen > bs) {
 		int err;
 
-		err = crypto_shash_digest(&desc.shash, inkey, keylen, ipad);
+		err = crypto_shash_digest(shash, inkey, keylen, ipad);
 		if (err)
 			return err;
 
@@ -81,12 +78,12 @@ static int hmac_setkey(struct crypto_shash *parent,
 		opad[i] ^= 0x5c;
 	}
 
-	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);
 }
 
 static int hmac_export(struct shash_desc *pdesc, void *out)
-- 
1.9.1

[PATCH v3 10/12] crypto: LLVMLinux: Remove VLAIS usage from libcrc32c.c

[behanw]

From: Jan-Simon Möller <dl9pf@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 <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: pageexec@freemail.hu
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
---
 lib/libcrc32c.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c
index b3131f5..6a08ce7 100644
--- a/lib/libcrc32c.c
+++ b/lib/libcrc32c.c
@@ -41,20 +41,18 @@ static struct crypto_shash *tfm;
 
 u32 crc32c(u32 crc, const void *address, unsigned int length)
 {
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(tfm)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, tfm);
+	u32 *ctx = (u32 *)shash_desc_ctx(shash);
 	int err;
 
-	desc.shash.tfm = tfm;
-	desc.shash.flags = 0;
-	*(u32 *)desc.ctx = crc;
+	shash->tfm = tfm;
+	shash->flags = 0;
+	*ctx = crc;
 
-	err = crypto_shash_update(&desc.shash, address, length);
+	err = crypto_shash_update(shash, address, length);
 	BUG_ON(err);
 
-	return *(u32 *)desc.ctx;
+	return *ctx;
 }
 
 EXPORT_SYMBOL(crc32c);
-- 
1.9.1

[PATCH v3 11/12] security, crypto: LLVMLinux: Remove VLAIS from ima_crypto.c

[behanw]

From: Behan Webster <behanw@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 a char array using the SHASH_DESC_ON_STACK macro.

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

Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
Cc: tglx@linutronix.de
---
 security/integrity/ima/ima_crypto.c | 51 +++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 28 deletions(-)

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 0bd7328..bb55737 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -380,17 +380,14 @@ static int ima_calc_file_hash_tfm(struct file *file,
 	loff_t i_size, offset = 0;
 	char *rbuf;
 	int rc, read = 0;
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(tfm)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, tfm);
 
-	desc.shash.tfm = tfm;
-	desc.shash.flags = 0;
+	shash->tfm = tfm;
+	shash->flags = 0;
 
 	hash->length = crypto_shash_digestsize(tfm);
 
-	rc = crypto_shash_init(&desc.shash);
+	rc = crypto_shash_init(shash);
 	if (rc != 0)
 		return rc;
 
@@ -420,7 +417,7 @@ static int ima_calc_file_hash_tfm(struct file *file,
 			break;
 		offset += rbuf_len;
 
-		rc = crypto_shash_update(&desc.shash, rbuf, rbuf_len);
+		rc = crypto_shash_update(shash, rbuf, rbuf_len);
 		if (rc)
 			break;
 	}
@@ -429,7 +426,7 @@ static int ima_calc_file_hash_tfm(struct file *file,
 	kfree(rbuf);
 out:
 	if (!rc)
-		rc = crypto_shash_final(&desc.shash, hash->digest);
+		rc = crypto_shash_final(shash, hash->digest);
 	return rc;
 }
 
@@ -487,18 +484,17 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 					 struct ima_digest_data *hash,
 					 struct crypto_shash *tfm)
 {
-	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;
 	int rc, i;
 
-	desc.shash.tfm = tfm;
-	desc.shash.flags = 0;
+	shash->tfm = tfm;
+	shash->flags = 0;
 
 	hash->length = crypto_shash_digestsize(tfm);
 
-	rc = crypto_shash_init(&desc.shash);
+	rc = crypto_shash_init(shash);
 	if (rc != 0)
 		return rc;
 
@@ -508,7 +504,7 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 		u32 datalen = field_data[i].len;
 
 		if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
-			rc = crypto_shash_update(&desc.shash,
+			rc = crypto_shash_update(shash,
 						(const u8 *) &field_data[i].len,
 						sizeof(field_data[i].len));
 			if (rc)
@@ -518,13 +514,13 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 			data_to_hash = buffer;
 			datalen = IMA_EVENT_NAME_LEN_MAX + 1;
 		}
-		rc = crypto_shash_update(&desc.shash, data_to_hash, datalen);
+		rc = crypto_shash_update(shash, data_to_hash, datalen);
 		if (rc)
 			break;
 	}
 
 	if (!rc)
-		rc = crypto_shash_final(&desc.shash, hash->digest);
+		rc = crypto_shash_final(shash, hash->digest);
 
 	return rc;
 }
@@ -565,15 +561,14 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest,
 {
 	u8 pcr_i[TPM_DIGEST_SIZE];
 	int rc, i;
-	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 = 0;
+	shash->tfm = tfm;
+	shash->flags = 0;
 
-	rc = crypto_shash_init(&desc.shash);
+	rc = crypto_shash_init(shash);
 	if (rc != 0)
 		return rc;
 
@@ -581,10 +576,10 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest,
 	for (i = TPM_PCR0; i < TPM_PCR8; i++) {
 		ima_pcrread(i, pcr_i);
 		/* now accumulate with current aggregate */
-		rc = crypto_shash_update(&desc.shash, pcr_i, TPM_DIGEST_SIZE);
+		rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
 	}
 	if (!rc)
-		crypto_shash_final(&desc.shash, digest);
+		crypto_shash_final(shash, digest);
 	return rc;
 }
 
-- 
1.9.1

[PATCH v3 12/12] crypto: LLVMLinux: Remove VLAIS usage from crypto/testmgr.c

[behanw]

From: Jan-Simon Möller <dl9pf@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 <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: pageexec@freemail.hu
---
 crypto/testmgr.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index ac2b631..b959c0c 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1714,16 +1714,14 @@ static int alg_test_crc32c(const struct alg_test_desc *desc,
 	}
 
 	do {
-		struct {
-			struct shash_desc shash;
-			char ctx[crypto_shash_descsize(tfm)];
-		} sdesc;
+		SHASH_DESC_ON_STACK(shash, tfm);
+		u32 *ctx = (u32 *)shash_desc_ctx(shash);
 
-		sdesc.shash.tfm = tfm;
-		sdesc.shash.flags = 0;
+		shash->tfm = tfm;
+		shash->flags = 0;
 
-		*(u32 *)sdesc.ctx = le32_to_cpu(420553207);
-		err = crypto_shash_final(&sdesc.shash, (u8 *)&val);
+		*ctx = le32_to_cpu(420553207);
+		err = crypto_shash_final(shash, (u8 *)&val);
 		if (err) {
 			printk(KERN_ERR "alg: crc32c: Operation failed for "
 			       "%s: %d\n", driver, err);
-- 
1.9.1

Re: [dm-devel] [PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

[Michał Mirosław]

2014-09-15 9:30 GMT+02:00  <behanw@converseincode.com>:
[...]
> +#define SHASH_DESC_ON_STACK(shash, tfm)                                  \
> +       char __desc[sizeof(struct shash_desc) +                   \
> +               crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR; \
> +       struct shash_desc *shash = (struct shash_desc *)__desc
> +

char shash##__desc[] or similar? Otherwise it won't work if you use
this macro twice in the same block.

Best Regards,
Michał Mirosław

Re: [dm-devel] [PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

[Behan Webster]

On 09/15/14 01:06, Michał Mirosław wrote:
> 2014-09-15 9:30 GMT+02:00  <behanw@converseincode.com>:
> [...]
>> +#define SHASH_DESC_ON_STACK(shash, tfm)                                  \
>> +       char __desc[sizeof(struct shash_desc) +                   \
>> +               crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR; \
>> +       struct shash_desc *shash = (struct shash_desc *)__desc
>> +
> char shash##__desc[] or similar? Otherwise it won't work if you use
> this macro twice in the same block.
>
> Best Regards,
> Michał Mirosław
Good thinking. Will fix.

Behan

-- 
Behan Webster
behanw@converseincode.com

Re: [PATCH v3 11/12] security, crypto: LLVMLinux: Remove VLAIS from ima_crypto.c

[Linus Torvalds]

On Mon, Sep 15, 2014 at 12:30 AM,  <behanw@converseincode.com> wrote:
> From: Behan Webster <behanw@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 a char array using the SHASH_DESC_ON_STACK macro.

You only made the first case use SHASH_DESC_ON_STACK, the two other
cases you left in the ugly format. Was that just an oversight, or was
there some reason for it?

             Linus

Re: [PATCH v3 11/12] security, crypto: LLVMLinux: Remove VLAIS from ima_crypto.c

[Behan Webster]

On 09/15/14 07:21, Linus Torvalds wrote:
> On Mon, Sep 15, 2014 at 12:30 AM,  <behanw@converseincode.com> wrote:
>> From: Behan Webster <behanw@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 a char array using the SHASH_DESC_ON_STACK macro.
> You only made the first case use SHASH_DESC_ON_STACK, the two other
> cases you left in the ugly format. Was that just an oversight, or was
> there some reason for it?
>
Oversight. Will Fix.

Behan

-- 
Behan Webster
behanw@converseincode.com

Re: [PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

[Herbert Xu]

On Mon, Sep 15, 2014 at 12:30:23AM -0700, behanw@converseincode.com wrote:
> From: Behan Webster <behanw@converseincode.com>
> 
> Add a macro which replaces the use of a Variable Length Array In Struct (VLAIS)
> with a C99 compliant equivalent. This macro instead 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 <behanw@converseincode.com>

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

[Dmitry Kasatkin]

On 17/09/14 12:22, Herbert Xu wrote:
> On Mon, Sep 15, 2014 at 12:30:23AM -0700, behanw@converseincode.com wrote:
>> From: Behan Webster <behanw@converseincode.com>
>>
>> Add a macro which replaces the use of a Variable Length Array In Struct (VLAIS)
>> with a C99 compliant equivalent. This macro instead 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 <behanw@converseincode.com>
> Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
>
> Thanks,

Just in case.
I would still follow advice from "Michał Mirosław" to use shash##__desc[]

- Dmitry

Re: [PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

[Herbert Xu]

On Wed, Sep 17, 2014 at 02:15:40PM +0300, Dmitry Kasatkin wrote:
> On 17/09/14 12:22, Herbert Xu wrote:
> > On Mon, Sep 15, 2014 at 12:30:23AM -0700, behanw@converseincode.com wrote:
> >> From: Behan Webster <behanw@converseincode.com>
> >>
> >> Add a macro which replaces the use of a Variable Length Array In Struct (VLAIS)
> >> with a C99 compliant equivalent. This macro instead 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 <behanw@converseincode.com>
> > Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
> >
> > Thanks,
> 
> Just in case.
> I would still follow advice from "Michał Mirosław" to use shash##__desc[]

Oh yes of course.  My ack is more about the approach.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v3 02/12] btrfs: LLVMLinux: Remove VLAIS

[Chris Mason]

On 09/15/2014 03:30 AM, behanw@converseincode.com wrote:
> From: Vinícius Tinti <viniciustinti@gmail.com>
> 
> Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
> compliant equivalent. This is the original VLAIS struct.
> 
> struct {
> 	struct shash_desc shash;
> 	char ctx[crypto_shash_descsize(tfm)];
> } desc;
> 
> This patch instead 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: Vinícius Tinti <viniciustinti@gmail.com>
> Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
> Reviewed-by: Mark Charlebois <charlebm@gmail.com>
> Signed-off-by: Behan Webster <behanw@converseincode.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>

Acked-by: Chris Mason <clm@fb.com>

On the btrfs bits.  Thanks for the v3.

-chris

Re: [PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

[Behan Webster]

On 09/17/14 04:30, Herbert Xu wrote:
> On Wed, Sep 17, 2014 at 02:15:40PM +0300, Dmitry Kasatkin wrote:
>> On 17/09/14 12:22, Herbert Xu wrote:
>>> On Mon, Sep 15, 2014 at 12:30:23AM -0700, behanw@converseincode.com wrote:
>>>> From: Behan Webster <behanw@converseincode.com>
>>>>
>>>> Add a macro which replaces the use of a Variable Length Array In Struct (VLAIS)
>>>> with a C99 compliant equivalent. This macro instead 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 <behanw@converseincode.com>
>>> Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
>>>
>>> Thanks,
>> Just in case.
>> I would still follow advice from "Michał Mirosław" to use shash##__desc[]
Absolutely. I will be posting a v4 patchset . Just waiting a bit more 
for more comments on v3.

The macro from v4 will look like this which I believe will satisfy the 
concern and indeed be safer than my previous version.

+#define SHASH_DESC_ON_STACK(shash, tfm)                                  \
+       char __##shash##_desc[sizeof(struct shash_desc) +        \
+               crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR; \
+       struct shash_desc *shash = (struct shash_desc *)__##shash##_desc

Hmm. Is it worth adding a comment with this macro explaining the reason this works? Essentially much of what is in the commit message?
  

> Oh yes of course.  My ack is more about the approach.

Wonderful!

Indeed. I would have asked for you to wait for v4 anyways. :)

Thank you,

Behan

-- 
Behan Webster
behanw@converseincode.com