[PATCH 2/2] Remove VLAIS usage from crypto/testmgr.c

[Behan Webster <behanw@converseincode.com>]

From: Jan-Simon Möller <dl9pf@gmx.de>

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

Patch from series at
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120507/142707.html
by PaX Team.

Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Cc: pageexec@freemail.hu
Signed-off-by: Behan Webster <behanw@converseincode.com>
---
 crypto/testmgr.c |   23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 941d75c..5b7b3a6 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1578,16 +1578,19 @@ static int alg_test_crc32c(const struct alg_test_desc *desc,
 	}
 
 	do {
-		struct {
-			struct shash_desc shash;
-			char ctx[crypto_shash_descsize(tfm)];
-		} sdesc;
-
-		sdesc.shash.tfm = tfm;
-		sdesc.shash.flags = 0;
-
-		*(u32 *)sdesc.ctx = le32_to_cpu(420553207);
-		err = crypto_shash_final(&sdesc.shash, (u8 *)&val);
+		char sdesc[sizeof(struct shash_desc)
+			+ crypto_shash_descsize(tfm)
+			+ CRYPTO_MINALIGN] CRYPTO_MINALIGN_ATTR;
+		struct shash_desc *shash = (struct shash_desc *)sdesc;
+		u32 *ctx = (u32 *)((unsigned long)(sdesc
+			+ sizeof(struct shash_desc) + CRYPTO_MINALIGN - 1)
+			& ~(CRYPTO_MINALIGN - 1));
+
+		shash->tfm = tfm;
+		shash->flags = 0;
+
+		*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);
-- 
1.7.9.5