crypto: rng - RNG interface and implementation

This patch adds a random number generator interface as well as a
cryptographic pseudo-random number generator based on AES.  It is
meant to be used in cases where a deterministic CPRNG is required.

One of the first applications will be as an input in the IPsec IV
generation process.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 126 insertions, 0 deletions

diff --git a/include/crypto/internal/rng.h b/include/crypto/internal/rng.h
new file mode 100644
index 00000000000..89697336957
--- /dev/null
+++ b/include/crypto/internal/rng.h
@@ -0,0 +1,26 @@
+/*
+ * RNG: Random Number Generator  algorithms under the crypto API
+ *
+ * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#ifndef _CRYPTO_INTERNAL_RNG_H
+#define _CRYPTO_INTERNAL_RNG_H
+
+#include <crypto/algapi.h>
+#include <crypto/rng.h>
+
+extern const struct crypto_type crypto_rng_type;
+
+static inline void *crypto_rng_ctx(struct crypto_rng *tfm)
+{
+	return crypto_tfm_ctx(&tfm->base);
+}
+
+#endif
diff --git a/include/crypto/rng.h b/include/crypto/rng.h
new file mode 100644
index 00000000000..c93f9b91792
--- /dev/null
+++ b/include/crypto/rng.h
@@ -0,0 +1,75 @@
+/*
+ * RNG: Random Number Generator  algorithms under the crypto API
+ *
+ * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#ifndef _CRYPTO_RNG_H
+#define _CRYPTO_RNG_H
+
+#include <linux/crypto.h>
+
+extern struct crypto_rng *crypto_default_rng;
+
+int crypto_get_default_rng(void);
+void crypto_put_default_rng(void);
+
+static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm)
+{
+	return (struct crypto_rng *)tfm;
+}
+
+static inline struct crypto_rng *crypto_alloc_rng(const char *alg_name,
+						  u32 type, u32 mask)
+{
+	type &= ~CRYPTO_ALG_TYPE_MASK;
+	type |= CRYPTO_ALG_TYPE_RNG;
+	mask |= CRYPTO_ALG_TYPE_MASK;
+
+	return __crypto_rng_cast(crypto_alloc_base(alg_name, type, mask));
+}
+
+static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm)
+{
+	return &tfm->base;
+}
+
+static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm)
+{
+	return &crypto_rng_tfm(tfm)->__crt_alg->cra_rng;
+}
+
+static inline struct rng_tfm *crypto_rng_crt(struct crypto_rng *tfm)
+{
+	return &crypto_rng_tfm(tfm)->crt_rng;
+}
+
+static inline void crypto_free_rng(struct crypto_rng *tfm)
+{
+	crypto_free_tfm(crypto_rng_tfm(tfm));
+}
+
+static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,
+				       u8 *rdata, unsigned int dlen)
+{
+	return crypto_rng_crt(tfm)->rng_gen_random(tfm, rdata, dlen);
+}
+
+static inline int crypto_rng_reset(struct crypto_rng *tfm,
+				   u8 *seed, unsigned int slen)
+{
+	return crypto_rng_crt(tfm)->rng_reset(tfm, seed, slen);
+}
+
+static inline int crypto_rng_seedsize(struct crypto_rng *tfm)
+{
+	return crypto_rng_alg(tfm)->seedsize;
+}
+
+#endif
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 81d994a3bda..3d2317e4af2 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -38,6 +38,7 @@
 #define CRYPTO_ALG_TYPE_DIGEST		0x00000008
 #define CRYPTO_ALG_TYPE_HASH		0x00000009
 #define CRYPTO_ALG_TYPE_AHASH		0x0000000a
+#define CRYPTO_ALG_TYPE_RNG		0x0000000c
 
 #define CRYPTO_ALG_TYPE_HASH_MASK	0x0000000e
 #define CRYPTO_ALG_TYPE_AHASH_MASK	0x0000000c
@@ -113,6 +114,7 @@ struct crypto_aead;
 struct crypto_blkcipher;
 struct crypto_hash;
 struct crypto_ahash;
+struct crypto_rng;
 struct crypto_tfm;
 struct crypto_type;
 struct aead_givcrypt_request;
@@ -298,6 +300,15 @@ struct compress_alg {
 			      unsigned int slen, u8 *dst, unsigned int *dlen);
 };
 
+struct rng_alg {
+	int (*rng_make_random)(struct crypto_rng *tfm, u8 *rdata,
+			       unsigned int dlen);
+	int (*rng_reset)(struct crypto_rng *tfm, u8 *seed, unsigned int slen);
+
+	unsigned int seedsize;
+};
+
+
 #define cra_ablkcipher	cra_u.ablkcipher
 #define cra_aead	cra_u.aead
 #define cra_blkcipher	cra_u.blkcipher
@@ -306,6 +317,7 @@ struct compress_alg {
 #define cra_hash	cra_u.hash
 #define cra_ahash	cra_u.ahash
 #define cra_compress	cra_u.compress
+#define cra_rng		cra_u.rng
 
 struct crypto_alg {
 	struct list_head cra_list;
@@ -333,6 +345,7 @@ struct crypto_alg {
 		struct hash_alg hash;
 		struct ahash_alg ahash;
 		struct compress_alg compress;
+		struct rng_alg rng;
 	} cra_u;
 
 	int (*cra_init)(struct crypto_tfm *tfm);
@@ -438,6 +451,12 @@ struct compress_tfm {
 	                      u8 *dst, unsigned int *dlen);
 };
 
+struct rng_tfm {
+	int (*rng_gen_random)(struct crypto_rng *tfm, u8 *rdata,
+			      unsigned int dlen);
+	int (*rng_reset)(struct crypto_rng *tfm, u8 *seed, unsigned int slen);
+};
+
 #define crt_ablkcipher	crt_u.ablkcipher
 #define crt_aead	crt_u.aead
 #define crt_blkcipher	crt_u.blkcipher
@@ -445,6 +464,7 @@ struct compress_tfm {
 #define crt_hash	crt_u.hash
 #define crt_ahash	crt_u.ahash
 #define crt_compress	crt_u.compress
+#define crt_rng		crt_u.rng
 
 struct crypto_tfm {
 
@@ -458,6 +478,7 @@ struct crypto_tfm {
 		struct hash_tfm hash;
 		struct ahash_tfm ahash;
 		struct compress_tfm compress;
+		struct rng_tfm rng;
 	} crt_u;
 	
 	struct crypto_alg *__crt_alg;
@@ -489,6 +510,10 @@ struct crypto_hash {
 	struct crypto_tfm base;
 };
 
+struct crypto_rng {
+	struct crypto_tfm base;
+};
+
 enum {
 	CRYPTOA_UNSPEC,
 	CRYPTOA_ALG,