1 files changed, 54 insertions, 6 deletions

diff --git a/crypto/api.c b/crypto/api.c
index 394169a..b472881 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -13,9 +13,12 @@
  * any later version.
  *
  */
+
+#include <linux/compiler.h>
 #include <linux/init.h>
 #include <linux/crypto.h>
 #include <linux/errno.h>
+#include <linux/kmod.h>
 #include <linux/rwsem.h>
 #include <linux/slab.h>
 #include "internal.h"
@@ -33,7 +36,7 @@ static inline void crypto_alg_put(struct crypto_alg *alg)
 	module_put(alg->cra_module);
 }
 
-struct crypto_alg *crypto_alg_lookup(const char *name)
+static struct crypto_alg *crypto_alg_lookup(const char *name)
 {
 	struct crypto_alg *q, *alg = NULL;
 
@@ -54,6 +57,13 @@ struct crypto_alg *crypto_alg_lookup(const char *name)
 	return alg;
 }
 
+/* A far more intelligent version of this is planned.  For now, just
+ * try an exact match on the name of the algorithm. */
+static inline struct crypto_alg *crypto_alg_mod_lookup(const char *name)
+{
+	return try_then_request_module(crypto_alg_lookup(name), name);
+}
+
 static int crypto_init_flags(struct crypto_tfm *tfm, u32 flags)
 {
 	tfm->crt_flags = 0;
@@ -117,20 +127,46 @@ 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;
 	
@@ -155,8 +191,14 @@ out:
 
 void crypto_free_tfm(struct crypto_tfm *tfm)
 {
-	struct crypto_alg *alg = tfm->__crt_alg;
-	int size = sizeof(*tfm) + alg->cra_ctxsize;
+	struct crypto_alg *alg;
+	int size;
+
+	if (unlikely(!tfm))
+		return;
+
+	alg = tfm->__crt_alg;
+	size = sizeof(*tfm) + alg->cra_ctxsize;
 
 	crypto_exit_ops(tfm);
 	crypto_alg_put(alg);
@@ -168,6 +210,12 @@ int crypto_register_alg(struct crypto_alg *alg)
 {
 	int ret = 0;
 	struct crypto_alg *q;
+
+	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
+		return -EINVAL;
+
+	if (alg->cra_alignmask > PAGE_SIZE)
+		return -EINVAL;
 	
 	down_write(&crypto_alg_sem);