/*
* Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
*
- * Licensed under the OpenSSL license (the "License"). You may not use
+ * Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
# include <openssl/hmac.h>
# include <openssl/ec.h>
# include <openssl/rand_drbg.h>
+# include "internal/tsan_assist.h"
+# include "internal/rand_int.h"
+
+# include "internal/numbers.h"
/* How many times to read the TSC as a randomness source. */
# define TSC_READ_COUNT 4
# define MASTER_RESEED_TIME_INTERVAL (60*60) /* 1 hour */
# define SLAVE_RESEED_TIME_INTERVAL (7*60) /* 7 minutes */
+/*
+ * The number of bytes that constitutes an atomic lump of entropy with respect
+ * to the FIPS 140-2 section 4.9.2 Conditional Tests. The size is somewhat
+ * arbitrary, the smaller the value, the less entropy is consumed on first
+ * read but the higher the probability of the test failing by accident.
+ *
+ * The value is in bytes.
+ */
+#define CRNGT_BUFSIZ 16
-
-/* Max size of additional input and personalization string. */
-# define DRBG_MAX_LENGTH 4096
+/*
+ * Maximum input size for the DRBG (entropy, nonce, personalization string)
+ *
+ * NIST SP800 90Ar1 allows a maximum of (1 << 35) bits i.e., (1 << 32) bytes.
+ *
+ * We lower it to 'only' INT32_MAX bytes, which is equivalent to 2 gigabytes.
+ */
+# define DRBG_MAX_LENGTH INT32_MAX
+
+/* The default nonce */
+#ifdef CHARSET_EBCDIC
+# define DRBG_DEFAULT_PERS_STRING { 0x4f, 0x70, 0x65, 0x6e, 0x53, 0x53, \
+ 0x4c, 0x20, 0x4e, 0x49, 0x53, 0x54, 0x20, 0x53, 0x50, 0x20, 0x38, 0x30, \
+ 0x30, 0x2d, 0x39, 0x30, 0x41, 0x20, 0x44, 0x52, 0x42, 0x47, 0x00};
+#else
+# define DRBG_DEFAULT_PERS_STRING "OpenSSL NIST SP 800-90A DRBG"
+#endif
/*
- * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len
+ * Maximum allocation size for RANDOM_POOL buffers
+ *
+ * The max_len value for the buffer provided to the rand_drbg_get_entropy()
+ * callback is currently 2^31 bytes (2 gigabytes), if a derivation function
+ * is used. Since this is much too large to be allocated, the rand_pool_new()
+ * function chooses more modest values as default pool length, bounded
+ * by RAND_POOL_MIN_LENGTH and RAND_POOL_MAX_LENGTH
*
- * The current factor is large enough that the RAND_POOL can store a
- * random input which has a lousy entropy rate of 0.0625 bits per byte.
- * This input will be sent through the derivation function which 'compresses'
- * the low quality input into a high quality output.
+ * The choice of the RAND_POOL_FACTOR is large enough such that the
+ * RAND_POOL can store a random input which has a lousy entropy rate of
+ * 8/256 (= 0.03125) bits per byte. This input will be sent through the
+ * derivation function which 'compresses' the low quality input into a
+ * high quality output.
+ *
+ * The factor 1.5 below is the pessimistic estimate for the extra amount
+ * of entropy required when no get_nonce() callback is defined.
+ */
+# define RAND_POOL_FACTOR 256
+# define RAND_POOL_MAX_LENGTH (RAND_POOL_FACTOR * \
+ 3 * (RAND_DRBG_STRENGTH / 16))
+/*
+ * = (RAND_POOL_FACTOR * \
+ * 1.5 * (RAND_DRBG_STRENGTH / 8))
*/
-# define DRBG_MINMAX_FACTOR 128
+/*
+ * Initial allocation minimum.
+ *
+ * There is a distinction between the secure and normal allocation minimums.
+ * Ideally, the secure allocation size should be a power of two. The normal
+ * allocation size doesn't have any such restriction.
+ *
+ * The secure value is based on 128 bits of secure material, which is 16 bytes.
+ * Typically, the DRBGs will set a minimum larger than this so optimal
+ * allocation ought to take place (for full quality seed material).
+ *
+ * The normal value has been chosed by noticing that the rand_drbg_get_nonce
+ * function is usually the largest of the built in allocation (twenty four
+ * bytes and then appending another sixteen bytes). This means the buffer ends
+ * with 40 bytes. The value of forty eight is comfortably above this which
+ * allows some slack in the platform specific values used.
+ */
+# define RAND_POOL_MIN_ALLOCATION(secure) ((secure) ? 16 : 48)
/* DRBG status values */
typedef enum drbg_status_e {
} DRBG_STATUS;
-/* intantiate */
+/* instantiate */
typedef int (*RAND_DRBG_instantiate_fn)(RAND_DRBG *ctx,
const unsigned char *ent,
size_t entlen,
size_t entlen,
const unsigned char *adin,
size_t adinlen);
-/* generat output */
+/* generate output */
typedef int (*RAND_DRBG_generate_fn)(RAND_DRBG *ctx,
unsigned char *out,
size_t outlen,
RAND_DRBG_uninstantiate_fn uninstantiate;
} RAND_DRBG_METHOD;
+/* 888 bits from SP800-90Ar1 10.1 table 2 */
+#define HASH_PRNG_MAX_SEEDLEN (888/8)
+
+typedef struct rand_drbg_hash_st {
+ EVP_MD *md;
+ EVP_MD_CTX *ctx;
+ size_t blocklen;
+ unsigned char V[HASH_PRNG_MAX_SEEDLEN];
+ unsigned char C[HASH_PRNG_MAX_SEEDLEN];
+ /* Temporary value storage: should always exceed max digest length */
+ unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN];
+} RAND_DRBG_HASH;
+
+typedef struct rand_drbg_hmac_st {
+ EVP_MD *md;
+ HMAC_CTX *ctx;
+ size_t blocklen;
+ unsigned char K[EVP_MAX_MD_SIZE];
+ unsigned char V[EVP_MAX_MD_SIZE];
+} RAND_DRBG_HMAC;
/*
* The state of a DRBG AES-CTR.
typedef struct rand_drbg_ctr_st {
EVP_CIPHER_CTX *ctx;
EVP_CIPHER_CTX *ctx_df;
- const EVP_CIPHER *cipher;
+ EVP_CIPHER *cipher;
size_t keylen;
unsigned char K[32];
unsigned char V[16];
} RAND_DRBG_CTR;
+/*
+ * The 'random pool' acts as a dumb container for collecting random
+ * input from various entropy sources. The pool has no knowledge about
+ * whether its randomness is fed into a legacy RAND_METHOD via RAND_add()
+ * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the
+ * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and
+ * 4) cleanup the random pool again.
+ *
+ * The random pool contains no locking mechanism because its scope and
+ * lifetime is intended to be restricted to a single stack frame.
+ */
+struct rand_pool_st {
+ unsigned char *buffer; /* points to the beginning of the random pool */
+ size_t len; /* current number of random bytes contained in the pool */
+
+ int attached; /* true pool was attached to existing buffer */
+ int secure; /* 1: allocated on the secure heap, 0: otherwise */
+
+ size_t min_len; /* minimum number of random bytes requested */
+ size_t max_len; /* maximum number of random bytes (allocated buffer size) */
+ size_t alloc_len; /* current number of bytes allocated */
+ size_t entropy; /* current entropy count in bits */
+ size_t entropy_requested; /* requested entropy count in bits */
+};
+
/*
* The state of all types of DRBGs, even though we only have CTR mode
* right now.
*/
struct rand_drbg_st {
CRYPTO_RWLOCK *lock;
+ /* The library context this DRBG is associated with, if any */
+ OPENSSL_CTX *libctx;
RAND_DRBG *parent;
int secure; /* 1: allocated on the secure heap, 0: otherwise */
int type; /* the nid of the underlying algorithm */
/*
* Stores the value of the rand_fork_count global as of when we last
- * reseeded. The DRG reseeds automatically whenever drbg->fork_count !=
+ * reseeded. The DRBG reseeds automatically whenever drbg->fork_count !=
* rand_fork_count. Used to provide fork-safety and reseed this DRBG in
* the child process.
*/
unsigned short flags; /* various external flags */
/*
- * The random pool is used by RAND_add()/drbg_add() to attach random
+ * The random_data is used by RAND_add()/drbg_add() to attach random
* data to the global drbg, such that the rand_drbg_get_entropy() callback
* can pull it during instantiation and reseeding. This is necessary to
* reconcile the different philosophies of the RAND and the RAND_DRBG
* with respect to how randomness is added to the RNG during reseeding
* (see PR #4328).
*/
- struct rand_pool_st *pool;
+ struct rand_pool_st *seed_pool;
+
+ /*
+ * Auxiliary pool for additional data.
+ */
+ struct rand_pool_st *adin_pool;
/*
* The following parameters are setup by the per-type "init" function.
*
- * Currently the only type is CTR_DRBG, its init function is drbg_ctr_init().
+ * The supported types and their init functions are:
+ * (1) CTR_DRBG: drbg_ctr_init().
+ * (2) HMAC_DRBG: drbg_hmac_init().
+ * (3) HASH_DRBG: drbg_hash_init().
*
* The parameters are closely related to the ones described in
* section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
size_t min_noncelen, max_noncelen;
size_t max_perslen, max_adinlen;
- /* Counts the number of generate requests since the last reseed. */
- unsigned int generate_counter;
+ /*
+ * Counts the number of generate requests since the last reseed
+ * (Starts at 1). This value is the reseed_counter as defined in
+ * NIST SP 800-90Ar1
+ */
+ unsigned int reseed_gen_counter;
/*
* Maximum number of generate requests until a reseed is required.
* This value is ignored if it is zero.
* is added by RAND_add() or RAND_seed() will have an immediate effect on
* the output of RAND_bytes() resp. RAND_priv_bytes().
*/
- unsigned int reseed_counter;
+ TSAN_QUALIFIER unsigned int reseed_prop_counter;
+ unsigned int reseed_next_counter;
size_t seedlen;
DRBG_STATUS state;
/* Application data, mainly used in the KATs. */
CRYPTO_EX_DATA ex_data;
- /* Implementation specific data (currently only one implementation) */
+ /* Implementation specific data */
union {
RAND_DRBG_CTR ctr;
+ RAND_DRBG_HASH hash;
+ RAND_DRBG_HMAC hmac;
} data;
/* Implementation specific methods */
/* DRBG helpers */
int rand_drbg_restart(RAND_DRBG *drbg,
const unsigned char *buffer, size_t len, size_t entropy);
-
+size_t rand_drbg_seedlen(RAND_DRBG *drbg);
/* locking api */
int rand_drbg_lock(RAND_DRBG *drbg);
int rand_drbg_unlock(RAND_DRBG *drbg);
int rand_drbg_enable_locking(RAND_DRBG *drbg);
-/* initializes the AES-CTR DRBG implementation */
+/* initializes the DRBG implementation */
int drbg_ctr_init(RAND_DRBG *drbg);
+int drbg_hash_init(RAND_DRBG *drbg);
+int drbg_hmac_init(RAND_DRBG *drbg);
+
+/*
+ * Entropy call back for the FIPS 140-2 section 4.9.2 Conditional Tests.
+ * These need to be exposed for the unit tests.
+ */
+int rand_crngt_get_entropy_cb(OPENSSL_CTX *ctx, RAND_POOL *pool,
+ unsigned char *buf, unsigned char *md,
+ unsigned int *md_size);
+extern int (*crngt_get_entropy)(OPENSSL_CTX *ctx, RAND_POOL *pool,
+ unsigned char *buf, unsigned char *md,
+ unsigned int *md_size);
#endif
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