/*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
# include <openssl/sha.h>
# include <openssl/hmac.h>
# include <openssl/ec.h>
-# include "include/internal/rand.h"
+# include "internal/rand.h"
-/* we require 256 bits of randomness */
-# define RANDOMNESS_NEEDED (256 / 8)
+/* How many times to read the TSC as a randomness source. */
+# define TSC_READ_COUNT 4
+
+/* Maximum reseed intervals */
+# define MAX_RESEED_INTERVAL (1 << 24)
+# define MAX_RESEED_TIME_INTERVAL (1 << 20) /* approx. 12 days */
+
+/* Default reseed intervals */
+# define MASTER_RESEED_INTERVAL (1 << 8)
+# define SLAVE_RESEED_INTERVAL (1 << 16)
+# define MASTER_RESEED_TIME_INTERVAL (60*60) /* 1 hour */
+# define SLAVE_RESEED_TIME_INTERVAL (7*60) /* 7 minutes */
+
+
+
+/* Max size of additional input and personalization string. */
+# define DRBG_MAX_LENGTH 4096
+
+/*
+ * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len
+ *
+ * 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.
+ */
+# define DRBG_MINMAX_FACTOR 128
-/* Maximum count allowed in reseeding */
-#define MAX_RESEED (1 << 24)
/* DRBG status values */
-#define DRBG_STATUS_UNINITIALISED 0
-#define DRBG_STATUS_READY 1
-#define DRBG_STATUS_RESEED 2
-#define DRBG_STATUS_ERROR 3
+typedef enum drbg_status_e {
+ DRBG_UNINITIALISED,
+ DRBG_READY,
+ DRBG_ERROR
+} DRBG_STATUS;
+
+
+/* intantiate */
+typedef int (*RAND_DRBG_instantiate_fn)(RAND_DRBG *ctx,
+ const unsigned char *ent,
+ size_t entlen,
+ const unsigned char *nonce,
+ size_t noncelen,
+ const unsigned char *pers,
+ size_t perslen);
+/* reseed */
+typedef int (*RAND_DRBG_reseed_fn)(RAND_DRBG *ctx,
+ const unsigned char *ent,
+ size_t entlen,
+ const unsigned char *adin,
+ size_t adinlen);
+/* generat output */
+typedef int (*RAND_DRBG_generate_fn)(RAND_DRBG *ctx,
+ unsigned char *out,
+ size_t outlen,
+ const unsigned char *adin,
+ size_t adinlen);
+/* uninstantiate */
+typedef int (*RAND_DRBG_uninstantiate_fn)(RAND_DRBG *ctx);
+
+
+/*
+ * The DRBG methods
+ */
-/* A default maximum length: larger than any reasonable value used in pratice */
-#define DRBG_MAX_LENGTH 0x7ffffff0
+typedef struct rand_drbg_method_st {
+ RAND_DRBG_instantiate_fn instantiate;
+ RAND_DRBG_reseed_fn reseed;
+ RAND_DRBG_generate_fn generate;
+ RAND_DRBG_uninstantiate_fn uninstantiate;
+} RAND_DRBG_METHOD;
-typedef struct drbg_ctr_ctx_st {
+
+/*
+ * The state of a DRBG AES-CTR.
+ */
+typedef struct rand_drbg_ctr_st {
AES_KEY ks;
size_t keylen;
unsigned char K[32];
unsigned char bltmp[16];
size_t bltmp_pos;
unsigned char KX[48];
-} DRBG_CTR_CTX;
+} RAND_DRBG_CTR;
+
-struct drbg_ctx_st {
+/*
+ * The state of all types of DRBGs, even though we only have CTR mode
+ * right now.
+ */
+struct rand_drbg_st {
CRYPTO_RWLOCK *lock;
- DRBG_CTX *parent;
- int nid; /* the NID of the underlying algorithm */
- unsigned int flags; /* various external flags */
+ RAND_DRBG *parent;
+ int nid; /* the underlying algorithm */
+ int fork_count;
+ unsigned short flags; /* various external flags */
+
+ /*
+ * The random pool 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).
+ */
+ RAND_POOL *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 parameters are closely related to the ones described in
+ * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
+ * crucial difference: In the NIST standard, all counts are given
+ * in bits, whereas in OpenSSL entropy counts are given in bits
+ * and buffer lengths are given in bytes.
+ *
+ * Since this difference has lead to some confusion in the past,
+ * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
+ * the 'len' suffix has been added to all buffer sizes for
+ * clarification.
+ */
- /* The following parameters are setup by mechanism drbg_init() call */
int strength;
- size_t blocklength;
size_t max_request;
- size_t min_entropy, max_entropy;
- size_t min_nonce, max_nonce;
- size_t max_pers, max_adin;
- unsigned int reseed_counter;
+ size_t min_entropylen, max_entropylen;
+ 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;
+ /*
+ * Maximum number of generate requests until a reseed is required.
+ * This value is ignored if it is zero.
+ */
unsigned int reseed_interval;
+ /* Stores the time when the last reseeding occurred */
+ time_t reseed_time;
+ /*
+ * Specifies the maximum time interval (in seconds) between reseeds.
+ * This value is ignored if it is zero.
+ */
+ time_t reseed_time_interval;
+ /*
+ * Counts the number of reseeds since instantiation.
+ * This value is ignored if it is zero.
+ *
+ * This counter is used only for seed propagation from the <master> DRBG
+ * to its two children, the <public> and <private> DRBG. This feature is
+ * very special and its sole purpose is to ensure that any randomness which
+ * 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;
+
size_t seedlen;
- int status;
+ DRBG_STATUS state;
- /* Application data: typically (only?) used by test get_entropy */
+ /* Application data, mainly used in the KATs. */
CRYPTO_EX_DATA ex_data;
- /* Implementation specific structures */
- DRBG_CTR_CTX ctr;
+ /* Implementation specific data (currently only one implementation) */
+ union {
+ RAND_DRBG_CTR ctr;
+ } data;
- /* entropy gathering function */
- size_t (*get_entropy)(DRBG_CTX *ctx, unsigned char **pout,
- int entropy, size_t min_len, size_t max_len);
- /* Indicates we have finished with entropy buffer */
- void (*cleanup_entropy)(DRBG_CTX *ctx, unsigned char *out, size_t olen);
+ /* Implementation specific methods */
+ RAND_DRBG_METHOD *meth;
- /* nonce gathering function */
- size_t (*get_nonce)(DRBG_CTX *ctx, unsigned char **pout,
- int entropy, size_t min_len, size_t max_len);
- /* Indicates we have finished with nonce buffer */
- void (*cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen);
+ /* Callback functions. See comments in rand_lib.c */
+ RAND_DRBG_get_entropy_fn get_entropy;
+ RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
+ RAND_DRBG_get_nonce_fn get_nonce;
+ RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
};
+/* The global RAND method, and the global buffer and DRBG instance. */
+extern RAND_METHOD rand_meth;
+
+/* How often we've forked (only incremented in child). */
+extern int rand_fork_count;
+
+/* Hardware-based seeding functions. */
+size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
+size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
+
+/* DRBG entropy callbacks. */
+size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
+ unsigned char **pout,
+ int entropy, size_t min_len, size_t max_len);
+void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
+ unsigned char *out, size_t outlen);
+size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len);
+
+/* DRBG helpers */
+int rand_drbg_restart(RAND_DRBG *drbg,
+ const unsigned char *buffer, size_t len, size_t entropy);
-extern RAND_METHOD openssl_rand_meth;
-void rand_drbg_cleanup(void);
-
-int ctr_init(DRBG_CTX *dctx);
-int drbg_hash_init(DRBG_CTX *dctx);
-int drbg_hmac_init(DRBG_CTX *dctx);
-int ctr_uninstantiate(DRBG_CTX *dctx);
-int ctr_instantiate(DRBG_CTX *dctx,
- const unsigned char *ent, size_t entlen,
- const unsigned char *nonce, size_t noncelen,
- const unsigned char *pers, size_t perslen);
-int ctr_reseed(DRBG_CTX *dctx,
- const unsigned char *ent, size_t entlen,
- const unsigned char *adin, size_t adinlen);
-int ctr_generate(DRBG_CTX *dctx,
- unsigned char *out, size_t outlen,
- const unsigned char *adin, size_t adinlen);
+/* initializes the AES-CTR DRBG implementation */
+int drbg_ctr_init(RAND_DRBG *drbg);
#endif
projects / openssl.git / blobdiff