1 files changed, 252 insertions, 0 deletions
diff --git a/include/crypto/rng.h b/include/crypto/rng.h
new file mode 100644
index 0000000000..6abe5102e5
--- /dev/null
+++ b/include/crypto/rng.h
@@ -0,0 +1,252 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * RNG: Random Number Generator  algorithms under the crypto API
+ *
+ * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
+ * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#ifndef _CRYPTO_RNG_H
+#define _CRYPTO_RNG_H
+
+#include <linux/atomic.h>
+#include <linux/container_of.h>
+#include <linux/crypto.h>
+
+struct crypto_rng;
+
+/*
+ * struct crypto_istat_rng: statistics for RNG algorithm
+ * @generate_cnt:	number of RNG generate requests
+ * @generate_tlen:	total data size of generated data by the RNG
+ * @seed_cnt:		number of times the RNG was seeded
+ * @err_cnt:		number of error for RNG requests
+ */
+struct crypto_istat_rng {
+	atomic64_t generate_cnt;
+	atomic64_t generate_tlen;
+	atomic64_t seed_cnt;
+	atomic64_t err_cnt;
+};
+
+/**
+ * struct rng_alg - random number generator definition
+ *
+ * @generate:	The function defined by this variable obtains a
+ *		random number. The random number generator transform
+ *		must generate the random number out of the context
+ *		provided with this call, plus any additional data
+ *		if provided to the call.
+ * @seed:	Seed or reseed the random number generator.  With the
+ *		invocation of this function call, the random number
+ *		generator shall become ready for generation.  If the
+ *		random number generator requires a seed for setting
+ *		up a new state, the seed must be provided by the
+ *		consumer while invoking this function. The required
+ *		size of the seed is defined with @seedsize .
+ * @set_ent:	Set entropy that would otherwise be obtained from
+ *		entropy source.  Internal use only.
+ * @stat:	Statistics for rng algorithm
+ * @seedsize:	The seed size required for a random number generator
+ *		initialization defined with this variable. Some
+ *		random number generators does not require a seed
+ *		as the seeding is implemented internally without
+ *		the need of support by the consumer. In this case,
+ *		the seed size is set to zero.
+ * @base:	Common crypto API algorithm data structure.
+ */
+struct rng_alg {
+	int (*generate)(struct crypto_rng *tfm,
+			const u8 *src, unsigned int slen,
+			u8 *dst, unsigned int dlen);
+	int (*seed)(struct crypto_rng *tfm, const u8 *seed, unsigned int slen);
+	void (*set_ent)(struct crypto_rng *tfm, const u8 *data,
+			unsigned int len);
+
+#ifdef CONFIG_CRYPTO_STATS
+	struct crypto_istat_rng stat;
+#endif
+
+	unsigned int seedsize;
+
+	struct crypto_alg base;
+};
+
+struct crypto_rng {
+	struct crypto_tfm base;
+};
+
+extern struct crypto_rng *crypto_default_rng;
+
+int crypto_get_default_rng(void);
+void crypto_put_default_rng(void);
+
+/**
+ * DOC: Random number generator API
+ *
+ * The random number generator API is used with the ciphers of type
+ * CRYPTO_ALG_TYPE_RNG (listed as type "rng" in /proc/crypto)
+ */
+
+/**
+ * crypto_alloc_rng() -- allocate RNG handle
+ * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
+ *	      message digest cipher
+ * @type: specifies the type of the cipher
+ * @mask: specifies the mask for the cipher
+ *
+ * Allocate a cipher handle for a random number generator. The returned struct
+ * crypto_rng is the cipher handle that is required for any subsequent
+ * API invocation for that random number generator.
+ *
+ * For all random number generators, this call creates a new private copy of
+ * the random number generator that does not share a state with other
+ * instances. The only exception is the "krng" random number generator which
+ * is a kernel crypto API use case for the get_random_bytes() function of the
+ * /dev/random driver.
+ *
+ * Return: allocated cipher handle in case of success; IS_ERR() is true in case
+ *	   of an error, PTR_ERR() returns the error code.
+ */
+struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 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_alg *alg)
+{
+	return container_of(alg, struct rng_alg, base);
+}
+
+/**
+ * crypto_rng_alg - obtain name of RNG
+ * @tfm: cipher handle
+ *
+ * Return the generic name (cra_name) of the initialized random number generator
+ *
+ * Return: generic name string
+ */
+static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm)
+{
+	return __crypto_rng_alg(crypto_rng_tfm(tfm)->__crt_alg);
+}
+
+/**
+ * crypto_free_rng() - zeroize and free RNG handle
+ * @tfm: cipher handle to be freed
+ *
+ * If @tfm is a NULL or error pointer, this function does nothing.
+ */
+static inline void crypto_free_rng(struct crypto_rng *tfm)
+{
+	crypto_destroy_tfm(tfm, crypto_rng_tfm(tfm));
+}
+
+static inline struct crypto_istat_rng *rng_get_stat(struct rng_alg *alg)
+{
+#ifdef CONFIG_CRYPTO_STATS
+	return &alg->stat;
+#else
+	return NULL;
+#endif
+}
+
+static inline int crypto_rng_errstat(struct rng_alg *alg, int err)
+{
+	if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
+		return err;
+
+	if (err && err != -EINPROGRESS && err != -EBUSY)
+		atomic64_inc(&rng_get_stat(alg)->err_cnt);
+
+	return err;
+}
+
+/**
+ * crypto_rng_generate() - get random number
+ * @tfm: cipher handle
+ * @src: Input buffer holding additional data, may be NULL
+ * @slen: Length of additional data
+ * @dst: output buffer holding the random numbers
+ * @dlen: length of the output buffer
+ *
+ * This function fills the caller-allocated buffer with random
+ * numbers using the random number generator referenced by the
+ * cipher handle.
+ *
+ * Return: 0 function was successful; < 0 if an error occurred
+ */
+static inline int crypto_rng_generate(struct crypto_rng *tfm,
+				      const u8 *src, unsigned int slen,
+				      u8 *dst, unsigned int dlen)
+{
+	struct rng_alg *alg = crypto_rng_alg(tfm);
+
+	if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
+		struct crypto_istat_rng *istat = rng_get_stat(alg);
+
+		atomic64_inc(&istat->generate_cnt);
+		atomic64_add(dlen, &istat->generate_tlen);
+	}
+
+	return crypto_rng_errstat(alg,
+				  alg->generate(tfm, src, slen, dst, dlen));
+}
+
+/**
+ * crypto_rng_get_bytes() - get random number
+ * @tfm: cipher handle
+ * @rdata: output buffer holding the random numbers
+ * @dlen: length of the output buffer
+ *
+ * This function fills the caller-allocated buffer with random numbers using the
+ * random number generator referenced by the cipher handle.
+ *
+ * Return: 0 function was successful; < 0 if an error occurred
+ */
+static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,
+				       u8 *rdata, unsigned int dlen)
+{
+	return crypto_rng_generate(tfm, NULL, 0, rdata, dlen);
+}
+
+/**
+ * crypto_rng_reset() - re-initialize the RNG
+ * @tfm: cipher handle
+ * @seed: seed input data
+ * @slen: length of the seed input data
+ *
+ * The reset function completely re-initializes the random number generator
+ * referenced by the cipher handle by clearing the current state. The new state
+ * is initialized with the caller provided seed or automatically, depending
+ * on the random number generator type (the ANSI X9.31 RNG requires
+ * caller-provided seed, the SP800-90A DRBGs perform an automatic seeding).
+ * The seed is provided as a parameter to this function call. The provided seed
+ * should have the length of the seed size defined for the random number
+ * generator as defined by crypto_rng_seedsize.
+ *
+ * Return: 0 if the setting of the key was successful; < 0 if an error occurred
+ */
+int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed,
+		     unsigned int slen);
+
+/**
+ * crypto_rng_seedsize() - obtain seed size of RNG
+ * @tfm: cipher handle
+ *
+ * The function returns the seed size for the random number generator
+ * referenced by the cipher handle. This value may be zero if the random
+ * number generator does not implement or require a reseeding. For example,
+ * the SP800-90A DRBGs implement an automated reseeding after reaching a
+ * pre-defined threshold.
+ *
+ * Return: seed size for the random number generator
+ */
+static inline int crypto_rng_seedsize(struct crypto_rng *tfm)
+{
+	return crypto_rng_alg(tfm)->seedsize;
+}
+
+#endif