[CRYPTO] Ensure cit_iv is aligned correctly

This patch ensures that cit_iv is aligned according to cra_alignmask
by allocating it as part of the tfm structure.  As a side effect the
crypto layer will also guarantee that the tfm ctx area has enough space
to be aligned by cra_alignmask.  This allows us to remove the extra
space reservation from the Padlock driver.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

crypto/api.c

@@ -125,20 +125,46 @@ static void crypto_exit_ops(struct crypto_tfm *tfm)
 	}
 }
 
+static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags)
+{
+	unsigned int len;
+
+	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
+	default:
+		BUG();
+
+	case CRYPTO_ALG_TYPE_CIPHER:
+		len = crypto_cipher_ctxsize(alg, flags);
+		break;
+		
+	case CRYPTO_ALG_TYPE_DIGEST:
+		len = crypto_digest_ctxsize(alg, flags);
+		break;
+		
+	case CRYPTO_ALG_TYPE_COMPRESS:
+		len = crypto_compress_ctxsize(alg, flags);
+		break;
+	}
+
+	return len + alg->cra_alignmask;
+}
+
 struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
 {
 	struct crypto_tfm *tfm = NULL;
 	struct crypto_alg *alg;
+	unsigned int tfm_size;
 
 	alg = crypto_alg_mod_lookup(name);
 	if (alg == NULL)
 		goto out;
-	
-	tfm = kmalloc(sizeof(*tfm) + alg->cra_ctxsize, GFP_KERNEL);
+
+	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
+	tfm = kmalloc(tfm_size, GFP_KERNEL);
 	if (tfm == NULL)
 		goto out_put;
 
-	memset(tfm, 0, sizeof(*tfm) + alg->cra_ctxsize);
+	memset(tfm, 0, tfm_size);
 	
 	tfm->__crt_alg = alg;
 	

crypto/cipher.c

@@ -41,7 +41,7 @@ static unsigned int crypt_slow(const struct cipher_desc *desc,
 			       struct scatter_walk *in,
 			       struct scatter_walk *out, unsigned int bsize)
 {
-	unsigned int alignmask = desc->tfm->__crt_alg->cra_alignmask;
+	unsigned int alignmask = crypto_tfm_alg_alignmask(desc->tfm);
 	u8 buffer[bsize * 2 + alignmask];
 	u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 	u8 *dst = src + bsize;
@@ -98,7 +98,7 @@ static int crypt(const struct cipher_desc *desc,
 	struct scatter_walk walk_in, walk_out;
 	struct crypto_tfm *tfm = desc->tfm;
 	const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
-	unsigned int alignmask = tfm->__crt_alg->cra_alignmask;
+	unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
 	unsigned long buffer = 0;
 
 	if (!nbytes)
@@ -399,6 +399,8 @@ int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 	}
 	
 	if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
+		unsigned int align;
+		unsigned long addr;
 	    	
 	    	switch (crypto_tfm_alg_blocksize(tfm)) {
 	    	case 8:
@@ -418,9 +420,11 @@ int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 	    	}
 	    	
 		ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
-	    	ops->cit_iv = kmalloc(ops->cit_ivsize, GFP_KERNEL);
-		if (ops->cit_iv == NULL)
-			ret = -ENOMEM;
+		align = crypto_tfm_alg_alignmask(tfm) + 1;
+		addr = (unsigned long)crypto_tfm_ctx(tfm);
+		addr = ALIGN(addr, align);
+		addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
+		ops->cit_iv = (void *)addr;
 	}
 
 out:	
@@ -429,5 +433,4 @@ out:
 
 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
 {
-	kfree(tfm->crt_cipher.cit_iv);
 }

crypto/internal.h

@@ -16,6 +16,7 @@
 #include <linux/highmem.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
+#include <linux/kernel.h>
 #include <asm/kmap_types.h>
 
 extern enum km_type crypto_km_types[];
@@ -61,6 +62,33 @@ static inline void crypto_init_proc(void)
 { }
 #endif
 
+static inline unsigned int crypto_digest_ctxsize(struct crypto_alg *alg,
+						 int flags)
+{
+	return alg->cra_ctxsize;
+}
+
+static inline unsigned int crypto_cipher_ctxsize(struct crypto_alg *alg,
+						 int flags)
+{
+	unsigned int len = alg->cra_ctxsize;
+	
+	switch (flags & CRYPTO_TFM_MODE_MASK) {
+	case CRYPTO_TFM_MODE_CBC:
+		len = ALIGN(len, alg->cra_alignmask + 1);
+		len += alg->cra_blocksize;
+		break;
+	}
+
+	return len;
+}
+
+static inline unsigned int crypto_compress_ctxsize(struct crypto_alg *alg,
+						   int flags)
+{
+	return alg->cra_ctxsize;
+}
+
 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags);
 int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags);
 int crypto_init_compress_flags(struct crypto_tfm *tfm, u32 flags);

drivers/crypto/padlock-aes.c

@@ -465,8 +465,7 @@ static struct crypto_alg aes_alg = {
 	.cra_name		=	"aes",
 	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
 	.cra_blocksize		=	AES_BLOCK_SIZE,
-	.cra_ctxsize		=	sizeof(struct aes_ctx) +
-					PADLOCK_ALIGNMENT,
+	.cra_ctxsize		=	sizeof(struct aes_ctx),
 	.cra_alignmask		=	PADLOCK_ALIGNMENT - 1,
 	.cra_module		=	THIS_MODULE,
 	.cra_list		=	LIST_HEAD_INIT(aes_alg.cra_list),

include/linux/crypto.h

@@ -288,6 +288,11 @@ static inline unsigned int crypto_tfm_alg_digestsize(struct crypto_tfm *tfm)
 	return tfm->__crt_alg->cra_digest.dia_digestsize;
 }
 
+static inline unsigned int crypto_tfm_alg_alignmask(struct crypto_tfm *tfm)
+{
+	return tfm->__crt_alg->cra_alignmask;
+}
+
 static inline void *crypto_tfm_ctx(struct crypto_tfm *tfm)
 {
 	return (void *)&tfm[1];