#include "internal/cryptlib_int.h"
/*
- * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
- * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG.
+ * Support framework for NIST SP 800-90A DRBG
+ *
+ * See manual page RAND_DRBG(7) for a general overview.
*
* The OpenSSL model is to have new and free functions, and that new
* does all initialization. That is not the NIST model, which has
*/
/*
- * THE THREE SHARED DRBGs
- *
- * There are three shared DRBGs (master, public and private), which are
- * accessed concurrently by all threads.
+ * The three shared DRBG instances
*
- * THE MASTER DRBG
+ * There are three shared DRBG instances: <master>, <public>, and <private>.
+ */
+
+/*
+ * The <master> DRBG
*
* Not used directly by the application, only for reseeding the two other
* DRBGs. It reseeds itself by pulling either randomness from os entropy
- * sources or by consuming randomnes which was added by RAND_add()
- */
-static RAND_DRBG *drbg_master;
-/*+
- * DRBG HIERARCHY
- *
- * In addition there are DRBGs, which are not shared, but used only by a
- * single thread at every time, for example the DRBGs which are owned by
- * an SSL context. All DRBGs are organized in a hierarchical fashion
- * with the <master> DRBG as root.
+ * sources or by consuming randomness which was added by RAND_add().
*
- * This gives the following overall picture:
- *
- * <os entropy sources>
- * |
- * RAND_add() ==> <master> \
- * / \ | shared DRBGs (with locking)
- * <public> <private> /
- * |
- * <ssl> owned by an SSL context
- *
- * AUTOMATIC RESEEDING
- *
- * Before satisfying a generate request, a DRBG reseeds itself automatically,
- * if one of the following two conditions holds:
- *
- * - the number of generate requests since the last reseeding exceeds a
- * certain threshold, the so called |reseed_interval|. This behaviour
- * can be disabled by setting the |reseed_interval| to 0.
- *
- * - the time elapsed since the last reseeding exceeds a certain time
- * interval, the so called |reseed_time_interval|. This behaviour
- * can be disabled by setting the |reseed_time_interval| to 0.
- *
- * MANUAL RESEEDING
+ * The <master> DRBG is a global instance which is accessed concurrently by
+ * all threads. The necessary locking is managed automatically by its child
+ * DRBG instances during reseeding.
+ */
+static RAND_DRBG *master_drbg;
+/*
+ * The <public> DRBG
*
- * For the three shared DRBGs (and only for these) there is another way to
- * reseed them manually by calling RAND_seed() (or RAND_add() with a positive
- * |randomness| argument). This will immediately reseed the <master> DRBG.
- * The <public> and <private> DRBG will detect this on their next generate
- * call and reseed, pulling randomness from <master>.
+ * Used by default for generating random bytes using RAND_bytes().
*
- * LOCKING
+ * The <public> DRBG is thread-local, i.e., there is one instance per thread.
+ */
+static CRYPTO_THREAD_LOCAL public_drbg;
+/*
+ * The <private> DRBG
*
- * The three shared DRBGs are intended to be used concurrently, so they
- * support locking. The RAND methods take the locks automatically, so using
- * the RAND api (in particular RAND_bytes() and RAND_priv_bytes()) is
- * thread-safe. Note however that accessing the shared DRBGs directly via
- * the RAND_DRBG interface is *not* thread-safe.
+ * Used by default for generating private keys using RAND_priv_bytes()
*
- * All other DRBG instances don't support locking, because they are
- * intendended to be used by a single thread. Instead of accessing a single
- * DRBG instance concurrently from different threads, it is recommended to
- * instantiate a separate DRBG instance per thread. Using the same shared
- * DRBG (preferrably the public DRBG) as parent of DRBG instances on
- * different threads is safe.
+ * The <private> DRBG is thread-local, i.e., there is one instance per thread.
*/
+static CRYPTO_THREAD_LOCAL private_drbg;
+
/* NIST SP 800-90A DRBG recommends the use of a personalization string. */
static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG";
static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT;
-static CRYPTO_THREAD_LOCAL private_drbg_thread_local_key;
-static CRYPTO_THREAD_LOCAL public_drbg_thread_local_key;
/*
* Set the RAND_DRBG callbacks for obtaining entropy and nonce.
*
- * In the following, the signature and the semantics of the
- * get_entropy() and cleanup_entropy() callbacks are explained.
- *
- * GET_ENTROPY
- *
- * size_t get_entropy(RAND_DRBG *ctx,
- * unsigned char **pout,
- * int entropy,
- * size_t min_len, size_t max_len);
- *
- * This is a request to allocate and fill a buffer of size
- * |min_len| <= size <= |max_len| (in bytes) which contains
- * at least |entropy| bits of randomness. The buffer's address is
- * to be returned in |*pout| and the number of collected
- * randomness bytes (which may be less than the allocated size
- * of the buffer) as return value.
+ * Setting the callbacks is allowed only if the drbg has not been
+ * initialized yet. Otherwise, the operation will fail.
*
- * If the callback fails to acquire at least |entropy| bits of
- * randomness, it shall return a buffer length of 0.
- *
- * CLEANUP_ENTROPY
- *
- * void cleanup_entropy(RAND_DRBG *ctx,
- * unsigned char *out, size_t outlen);
- *
- * A request to clear and free the buffer allocated by get_entropy().
- * The values |out| and |outlen| are expected to be the random buffer's
- * address and length, as returned by the get_entropy() callback.
- *
- * GET_NONCE, CLEANUP_NONCE
- *
- * Signature and semantics of the get_nonce() and cleanup_nonce()
- * callbacks are analogous to get_entropy() and cleanup_entropy().
- * Currently, the nonce is used only for the known answer tests.
+ * Returns 1 on success, 0 on failure.
*/
int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
RAND_DRBG_get_entropy_fn get_entropy,
ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND);
- drbg_master = drbg_setup(NULL);
+ master_drbg = drbg_setup(NULL);
- ret &= CRYPTO_THREAD_init_local(&private_drbg_thread_local_key, NULL);
- ret &= CRYPTO_THREAD_init_local(&public_drbg_thread_local_key, NULL);
+ ret &= CRYPTO_THREAD_init_local(&private_drbg, NULL);
+ ret &= CRYPTO_THREAD_init_local(&public_drbg, NULL);
- if (drbg_master == NULL || ret == 0)
+ if (master_drbg == NULL || ret == 0)
return 0;
return 1;
/* Clean up the global DRBGs before exit */
void rand_drbg_cleanup_int(void)
{
- RAND_DRBG_free(drbg_master);
- drbg_master = NULL;
+ RAND_DRBG_free(master_drbg);
+ master_drbg = NULL;
- CRYPTO_THREAD_cleanup_local(&private_drbg_thread_local_key);
- CRYPTO_THREAD_cleanup_local(&public_drbg_thread_local_key);
+ CRYPTO_THREAD_cleanup_local(&private_drbg);
+ CRYPTO_THREAD_cleanup_local(&public_drbg);
}
void drbg_delete_thread_state()
{
RAND_DRBG *drbg;
- drbg = CRYPTO_THREAD_get_local(&public_drbg_thread_local_key);
+ drbg = CRYPTO_THREAD_get_local(&public_drbg);
RAND_DRBG_free(drbg);
- drbg = CRYPTO_THREAD_get_local(&private_drbg_thread_local_key);
+ drbg = CRYPTO_THREAD_get_local(&private_drbg);
RAND_DRBG_free(drbg);
}
if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
return NULL;
- return drbg_master;
+ return master_drbg;
}
/*
if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
return NULL;
- drbg = CRYPTO_THREAD_get_local(&public_drbg_thread_local_key);
+ drbg = CRYPTO_THREAD_get_local(&public_drbg);
if (drbg == NULL) {
ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND);
- drbg = drbg_setup(drbg_master);
- CRYPTO_THREAD_set_local(&public_drbg_thread_local_key, drbg);
+ drbg = drbg_setup(master_drbg);
+ CRYPTO_THREAD_set_local(&public_drbg, drbg);
}
return drbg;
}
if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
return NULL;
- drbg = CRYPTO_THREAD_get_local(&private_drbg_thread_local_key);
+ drbg = CRYPTO_THREAD_get_local(&private_drbg);
if (drbg == NULL) {
ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND);
- drbg = drbg_setup(drbg_master);
- CRYPTO_THREAD_set_local(&private_drbg_thread_local_key, drbg);
+ drbg = drbg_setup(master_drbg);
+ CRYPTO_THREAD_set_local(&private_drbg, drbg);
}
return drbg;
}
projects / openssl.git / blobdiff