/*
- * Copyright 2011-2017 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2011-2018 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/err.h>
#include <openssl/rand.h>
#include "rand_lcl.h"
+#include "internal/thread_once.h"
+#include "internal/rand_int.h"
/*
* Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
* a much bigger deal than just re-setting an allocated resource.)
*/
+/*
+ * THE THREE SHARED DRBGs
+ *
+ * There are three shared DRBGs (master, public and private), which are
+ * accessed concurrently by all threads.
+ *
+ * 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;
+/*
+ * THE PUBLIC DRBG
+ *
+ * Used by default for generating random bytes using RAND_bytes().
+ */
+static RAND_DRBG *drbg_public;
+/*
+ * THE PRIVATE DRBG
+ *
+ * Used by default for generating private keys using RAND_priv_bytes()
+ */
+static RAND_DRBG *drbg_private;
+/*+
+ * 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.
+ *
+ * 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
+ *
+ * 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>.
+ *
+ * LOCKING
+ *
+ * The three shared DRBGs are intended to be used concurrently, so they
+ * support locking by default. It is the callers responsibility to wrap
+ * calls to functions like RAND_DRBG_generate() which modify the DRBGs
+ * internal state with calls to RAND_DRBG_lock() and RAND_DRBG_unlock().
+ * The functions RAND_bytes() and RAND_priv_bytes() take the locks
+ * automatically, so using the RAND api is thread safe as before.
+ *
+ * All other DRBG instances don't have locking enabled by default, because
+ * they are intendended to be used by a single thread. If it is desired,
+ * locking can be enabled using RAND_DRBG_enable_locking(). However, instead
+ * of accessing a single DRBG instance concurrently from different threads,
+ * it is recommended to instantiate a separate DRBG instance per thread.
+ */
+
+
+/* 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 RAND_DRBG *drbg_setup(RAND_DRBG *parent);
+static void drbg_cleanup(RAND_DRBG *drbg);
+
/*
* Set/initialize |drbg| to be of type |nid|, with optional |flags|.
- * Return -2 if the type is not supported, 1 on success and -1 on
- * failure.
+ *
+ * Returns 1 on success, 0 on failure.
*/
int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags)
{
switch (nid) {
default:
RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
- return -2;
+ return 0;
case 0:
/* Uninitialized; that's okay. */
return 1;
case NID_aes_128_ctr:
case NID_aes_192_ctr:
case NID_aes_256_ctr:
- ret = ctr_init(drbg);
+ ret = drbg_ctr_init(drbg);
break;
}
- if (ret < 0)
+ if (ret == 0)
RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
return ret;
}
/*
* Allocate memory and initialize a new DRBG. The |parent|, if not
* NULL, will be used to auto-seed this RAND_DRBG as needed.
+ *
+ * Returns a pointer to the new DRBG instance on success, NULL on failure.
*/
RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
{
RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
- unsigned char *ucp = OPENSSL_zalloc(RANDOMNESS_NEEDED);
- if (drbg == NULL || ucp == NULL) {
+ if (drbg == NULL) {
RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
goto err;
}
- drbg->size = RANDOMNESS_NEEDED;
- drbg->randomness = ucp;
drbg->fork_count = rand_fork_count;
drbg->parent = parent;
- if (RAND_DRBG_set(drbg, type, flags) < 0)
+ if (RAND_DRBG_set(drbg, type, flags) == 0)
goto err;
- if (parent != NULL) {
- if (parent->state == DRBG_UNINITIALISED
- && RAND_DRBG_instantiate(parent, NULL, 0) == 0)
- goto err;
- if (!RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_parent,
- drbg_release_entropy,
- NULL, NULL)
- /*
- * Add in our address. Note we are adding the pointer
- * itself, not its contents!
- */
- || !RAND_DRBG_instantiate(drbg,
- (unsigned char*)&drbg, sizeof(drbg)))
- goto err;
- }
+ if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
+ rand_drbg_cleanup_entropy,
+ NULL, NULL))
+ goto err;
return drbg;
err:
- OPENSSL_free(ucp);
OPENSSL_free(drbg);
return NULL;
}
-RAND_DRBG *RAND_DRBG_get0_global(void)
-{
- return &rand_drbg;
-}
-
/*
* Uninstantiate |drbg| and free all memory.
*/
void RAND_DRBG_free(RAND_DRBG *drbg)
{
- /* The global DRBG is free'd by rand_cleanup_int() */
- if (drbg == NULL || drbg == &rand_drbg)
+ if (drbg == NULL)
return;
- ctr_uninstantiate(drbg);
- OPENSSL_cleanse(drbg->randomness, drbg->size);
- OPENSSL_free(drbg->randomness);
+ if (drbg->meth != NULL)
+ drbg->meth->uninstantiate(drbg);
CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
OPENSSL_clear_free(drbg, sizeof(*drbg));
}
/*
* Instantiate |drbg|, after it has been initialized. Use |pers| and
* |perslen| as prediction-resistance input.
+ *
+ * Requires that drbg->lock is already locked for write, if non-null.
+ *
+ * Returns 1 on success, 0 on failure.
*/
int RAND_DRBG_instantiate(RAND_DRBG *drbg,
const unsigned char *pers, size_t perslen)
{
unsigned char *nonce = NULL, *entropy = NULL;
- size_t noncelen = 0, entlen = 0;
+ size_t noncelen = 0, entropylen = 0;
- if (perslen > drbg->max_pers) {
+ if (perslen > drbg->max_perslen) {
RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
RAND_R_PERSONALISATION_STRING_TOO_LONG);
goto end;
}
+
+ if (drbg->meth == NULL)
+ {
+ RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
+ RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
+ goto end;
+ }
+
if (drbg->state != DRBG_UNINITIALISED) {
RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
drbg->state = DRBG_ERROR;
if (drbg->get_entropy != NULL)
- entlen = drbg->get_entropy(drbg, &entropy, drbg->strength,
- drbg->min_entropy, drbg->max_entropy);
- if (entlen < drbg->min_entropy || entlen > drbg->max_entropy) {
+ entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
+ drbg->min_entropylen, drbg->max_entropylen);
+ if (entropylen < drbg->min_entropylen
+ || entropylen > drbg->max_entropylen) {
RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
goto end;
}
- if (drbg->max_nonce > 0 && drbg->get_nonce != NULL) {
+ if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) {
noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
- drbg->min_nonce, drbg->max_nonce);
- if (noncelen < drbg->min_nonce || noncelen > drbg->max_nonce) {
- RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
+ drbg->min_noncelen, drbg->max_noncelen);
+ if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
+ RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
+ RAND_R_ERROR_RETRIEVING_NONCE);
goto end;
}
}
- if (!ctr_instantiate(drbg, entropy, entlen,
+ if (!drbg->meth->instantiate(drbg, entropy, entropylen,
nonce, noncelen, pers, perslen)) {
RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
goto end;
}
drbg->state = DRBG_READY;
- drbg->reseed_counter = 1;
+ drbg->generate_counter = 0;
+ drbg->reseed_time = time(NULL);
+ if (drbg->reseed_counter > 0) {
+ if (drbg->parent == NULL)
+ drbg->reseed_counter++;
+ else
+ drbg->reseed_counter = drbg->parent->reseed_counter;
+ }
end:
if (entropy != NULL && drbg->cleanup_entropy != NULL)
- drbg->cleanup_entropy(drbg, entropy);
+ drbg->cleanup_entropy(drbg, entropy, entropylen);
if (nonce != NULL && drbg->cleanup_nonce!= NULL )
- drbg->cleanup_nonce(drbg, nonce);
+ drbg->cleanup_nonce(drbg, nonce, noncelen);
+ if (drbg->pool != NULL) {
+ if (drbg->state == DRBG_READY) {
+ RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
+ RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
+ drbg->state = DRBG_ERROR;
+ }
+ RAND_POOL_free(drbg->pool);
+ drbg->pool = NULL;
+ }
if (drbg->state == DRBG_READY)
return 1;
return 0;
/*
* Uninstantiate |drbg|. Must be instantiated before it can be used.
+ *
+ * Requires that drbg->lock is already locked for write, if non-null.
+ *
+ * Returns 1 on success, 0 on failure.
*/
int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
{
- int ret = ctr_uninstantiate(drbg);
+ if (drbg->meth == NULL)
+ {
+ RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
+ RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
+ return 0;
+ }
- OPENSSL_cleanse(&drbg->ctr, sizeof(drbg->ctr));
- drbg->state = DRBG_UNINITIALISED;
- return ret;
+ /* Clear the entire drbg->ctr struct, then reset some important
+ * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
+ * initial values.
+ */
+ drbg->meth->uninstantiate(drbg);
+ return RAND_DRBG_set(drbg, drbg->nid, drbg->flags);
}
/*
- * Mix in the specified data to reseed |drbg|.
+ * Reseed |drbg|, mixing in the specified data
+ *
+ * Requires that drbg->lock is already locked for write, if non-null.
+ *
+ * Returns 1 on success, 0 on failure.
*/
int RAND_DRBG_reseed(RAND_DRBG *drbg,
const unsigned char *adin, size_t adinlen)
{
unsigned char *entropy = NULL;
- size_t entlen = 0;
+ size_t entropylen = 0;
if (drbg->state == DRBG_ERROR) {
RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
if (adin == NULL)
adinlen = 0;
- else if (adinlen > drbg->max_adin) {
+ else if (adinlen > drbg->max_adinlen) {
RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
return 0;
}
drbg->state = DRBG_ERROR;
if (drbg->get_entropy != NULL)
- entlen = drbg->get_entropy(drbg, &entropy, drbg->strength,
- drbg->min_entropy, drbg->max_entropy);
- if (entlen < drbg->min_entropy || entlen > drbg->max_entropy) {
+ entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
+ drbg->min_entropylen, drbg->max_entropylen);
+ if (entropylen < drbg->min_entropylen
+ || entropylen > drbg->max_entropylen) {
RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
goto end;
}
- if (!ctr_reseed(drbg, entropy, entlen, adin, adinlen))
+ if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
goto end;
+
drbg->state = DRBG_READY;
- drbg->reseed_counter = 1;
+ drbg->generate_counter = 0;
+ drbg->reseed_time = time(NULL);
+ if (drbg->reseed_counter > 0) {
+ if (drbg->parent == NULL)
+ drbg->reseed_counter++;
+ else
+ drbg->reseed_counter = drbg->parent->reseed_counter;
+ }
end:
if (entropy != NULL && drbg->cleanup_entropy != NULL)
- drbg->cleanup_entropy(drbg, entropy);
+ drbg->cleanup_entropy(drbg, entropy, entropylen);
if (drbg->state == DRBG_READY)
return 1;
return 0;
}
+/*
+ * Restart |drbg|, using the specified entropy or additional input
+ *
+ * Tries its best to get the drbg instantiated by all means,
+ * regardless of its current state.
+ *
+ * Optionally, a |buffer| of |len| random bytes can be passed,
+ * which is assumed to contain at least |entropy| bits of entropy.
+ *
+ * If |entropy| > 0, the buffer content is used as entropy input.
+ *
+ * If |entropy| == 0, the buffer content is used as additional input
+ *
+ * Returns 1 on success, 0 on failure.
+ *
+ * This function is used internally only.
+ */
+int rand_drbg_restart(RAND_DRBG *drbg,
+ const unsigned char *buffer, size_t len, size_t entropy)
+{
+ int reseeded = 0;
+ const unsigned char *adin = NULL;
+ size_t adinlen = 0;
+
+ if (drbg->pool != NULL) {
+ RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
+ RAND_POOL_free(drbg->pool);
+ drbg->pool = NULL;
+ }
+
+ if (buffer != NULL) {
+ if (entropy > 0) {
+ if (drbg->max_entropylen < len) {
+ RANDerr(RAND_F_RAND_DRBG_RESTART,
+ RAND_R_ENTROPY_INPUT_TOO_LONG);
+ return 0;
+ }
+
+ if (entropy > 8 * len) {
+ RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
+ return 0;
+ }
+
+ /* will be picked up by the rand_drbg_get_entropy() callback */
+ drbg->pool = RAND_POOL_new(entropy, len, len);
+ if (drbg->pool == NULL)
+ return 0;
+
+ RAND_POOL_add(drbg->pool, buffer, len, entropy);
+ } else {
+ if (drbg->max_adinlen < len) {
+ RANDerr(RAND_F_RAND_DRBG_RESTART,
+ RAND_R_ADDITIONAL_INPUT_TOO_LONG);
+ return 0;
+ }
+ adin = buffer;
+ adinlen = len;
+ }
+ }
+
+ /* repair error state */
+ if (drbg->state == DRBG_ERROR)
+ RAND_DRBG_uninstantiate(drbg);
+
+ /* repair uninitialized state */
+ if (drbg->state == DRBG_UNINITIALISED) {
+ /* reinstantiate drbg */
+ RAND_DRBG_instantiate(drbg,
+ (const unsigned char *) ossl_pers_string,
+ sizeof(ossl_pers_string) - 1);
+ /* already reseeded. prevent second reseeding below */
+ reseeded = (drbg->state == DRBG_READY);
+ }
+
+ /* refresh current state if entropy or additional input has been provided */
+ if (drbg->state == DRBG_READY) {
+ if (adin != NULL) {
+ /*
+ * mix in additional input without reseeding
+ *
+ * Similar to RAND_DRBG_reseed(), but the provided additional
+ * data |adin| is mixed into the current state without pulling
+ * entropy from the trusted entropy source using get_entropy().
+ * This is not a reseeding in the strict sense of NIST SP 800-90A.
+ */
+ drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
+ } else if (reseeded == 0) {
+ /* do a full reseeding if it has not been done yet above */
+ RAND_DRBG_reseed(drbg, NULL, 0);
+ }
+ }
+
+ /* check whether a given entropy pool was cleared properly during reseed */
+ if (drbg->pool != NULL) {
+ drbg->state = DRBG_ERROR;
+ RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
+ RAND_POOL_free(drbg->pool);
+ drbg->pool = NULL;
+ return 0;
+ }
+
+ return drbg->state == DRBG_READY;
+}
+
/*
* Generate |outlen| bytes into the buffer at |out|. Reseed if we need
* to or if |prediction_resistance| is set. Additional input can be
* sent in |adin| and |adinlen|.
+ *
+ * Requires that drbg->lock is already locked for write, if non-null.
+ *
+ * Returns 1 on success, 0 on failure.
+ *
*/
int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
int prediction_resistance,
const unsigned char *adin, size_t adinlen)
{
- if (drbg->state == DRBG_ERROR) {
- RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
- return 0;
- }
- if (drbg->state == DRBG_UNINITIALISED) {
- RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
- return 0;
+ int reseed_required = 0;
+
+ if (drbg->state != DRBG_READY) {
+ /* try to recover from previous errors */
+ rand_drbg_restart(drbg, NULL, 0, 0);
+
+ if (drbg->state == DRBG_ERROR) {
+ RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
+ return 0;
+ }
+ if (drbg->state == DRBG_UNINITIALISED) {
+ RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
+ return 0;
+ }
}
+
if (outlen > drbg->max_request) {
RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
return 0;
}
- if (adinlen > drbg->max_adin) {
+ if (adinlen > drbg->max_adinlen) {
RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
return 0;
}
if (drbg->fork_count != rand_fork_count) {
drbg->fork_count = rand_fork_count;
- drbg->state = DRBG_RESEED;
+ reseed_required = 1;
}
- if (drbg->reseed_counter >= drbg->reseed_interval)
- drbg->state = DRBG_RESEED;
+ if (drbg->reseed_interval > 0) {
+ if (drbg->generate_counter >= drbg->reseed_interval)
+ reseed_required = 1;
+ }
+ if (drbg->reseed_time_interval > 0) {
+ time_t now = time(NULL);
+ if (now < drbg->reseed_time
+ || now - drbg->reseed_time >= drbg->reseed_time_interval)
+ reseed_required = 1;
+ }
+ if (drbg->reseed_counter > 0 && drbg->parent != NULL) {
+ if (drbg->reseed_counter != drbg->parent->reseed_counter)
+ reseed_required = 1;
+ }
- if (drbg->state == DRBG_RESEED || prediction_resistance) {
+ if (reseed_required || prediction_resistance) {
if (!RAND_DRBG_reseed(drbg, adin, adinlen)) {
RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
return 0;
adinlen = 0;
}
- if (!ctr_generate(drbg, out, outlen, adin, adinlen)) {
+ if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
drbg->state = DRBG_ERROR;
RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
return 0;
}
- if (drbg->reseed_counter >= drbg->reseed_interval)
- drbg->state = DRBG_RESEED;
- else
- drbg->reseed_counter++;
+ drbg->generate_counter++;
+
return 1;
}
/*
- * Set the callbacks for entropy and nonce. We currently don't use
- * the nonce; that's mainly for the KATs
+ * Generates |outlen| random bytes and stores them in |out|. It will
+ * using the given |drbg| to generate the bytes.
+ *
+ * Requires that drbg->lock is already locked for write, if non-null.
+ *
+ * Returns 1 on success 0 on failure.
+ */
+int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
+{
+ unsigned char *additional = NULL;
+ size_t additional_len;
+ size_t chunk;
+ size_t ret;
+
+ additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
+
+ for ( ; outlen > 0; outlen -= chunk, out += chunk) {
+ chunk = outlen;
+ if (chunk > drbg->max_request)
+ chunk = drbg->max_request;
+ ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
+ if (!ret)
+ goto err;
+ }
+ ret = 1;
+
+err:
+ if (additional_len != 0)
+ OPENSSL_secure_clear_free(additional, additional_len);
+
+ return ret;
+}
+
+/*
+ * 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.
+ *
+ * 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.
*/
int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
- RAND_DRBG_get_entropy_fn cb_get_entropy,
- RAND_DRBG_cleanup_entropy_fn cb_cleanup_entropy,
- RAND_DRBG_get_nonce_fn cb_get_nonce,
- RAND_DRBG_cleanup_nonce_fn cb_cleanup_nonce)
+ 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)
{
if (drbg->state != DRBG_UNINITIALISED)
return 0;
- drbg->get_entropy = cb_get_entropy;
- drbg->cleanup_entropy = cb_cleanup_entropy;
- drbg->get_nonce = cb_get_nonce;
- drbg->cleanup_nonce = cb_cleanup_nonce;
+ drbg->get_entropy = get_entropy;
+ drbg->cleanup_entropy = cleanup_entropy;
+ drbg->get_nonce = get_nonce;
+ drbg->cleanup_nonce = cleanup_nonce;
return 1;
}
/*
* Set the reseed interval.
+ *
+ * The drbg will reseed automatically whenever the number of generate
+ * requests exceeds the given reseed interval. If the reseed interval
+ * is 0, then this feature is disabled.
+ *
+ * Returns 1 on success, 0 on failure.
*/
-int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, int interval)
+int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
{
- if (interval < 0 || interval > MAX_RESEED)
+ if (interval > MAX_RESEED_INTERVAL)
return 0;
drbg->reseed_interval = interval;
return 1;
}
+/*
+ * Set the reseed time interval.
+ *
+ * The drbg will reseed automatically whenever the time elapsed since
+ * the last reseeding exceeds the given reseed time interval. For safety,
+ * a reseeding will also occur if the clock has been reset to a smaller
+ * value.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
+{
+ if (interval > MAX_RESEED_TIME_INTERVAL)
+ return 0;
+ drbg->reseed_time_interval = interval;
+ return 1;
+}
+
+
+/*
+ * Locks the given drbg. Locking a drbg which does not have locking
+ * enabled is considered a successful no-op.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int RAND_DRBG_lock(RAND_DRBG *drbg)
+{
+ if (drbg->lock != NULL)
+ return CRYPTO_THREAD_write_lock(drbg->lock);
+
+ return 1;
+}
+
+/*
+ * Unlocks the given drbg. Unlocking a drbg which does not have locking
+ * enabled is considered a successful no-op.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int RAND_DRBG_unlock(RAND_DRBG *drbg)
+{
+ if (drbg->lock != NULL)
+ return CRYPTO_THREAD_unlock(drbg->lock);
+
+ return 1;
+}
+
+/*
+ * Enables locking for the given drbg
+ *
+ * Locking can only be enabled if the random generator
+ * is in the uninitialized state.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int RAND_DRBG_enable_locking(RAND_DRBG *drbg)
+{
+ if (drbg->state != DRBG_UNINITIALISED) {
+ RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
+ RAND_R_DRBG_ALREADY_INITIALIZED);
+ return 0;
+ }
+
+ if (drbg->lock == NULL) {
+ if (drbg->parent != NULL && drbg->lock == NULL) {
+ RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
+ RAND_R_PARENT_LOCKING_NOT_ENABLED);
+ return 0;
+ }
+
+ drbg->lock = CRYPTO_THREAD_lock_new();
+ if (drbg->lock == NULL) {
+ RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
+ RAND_R_FAILED_TO_CREATE_LOCK);
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
/*
* Get and set the EXDATA
*/
* global DRBG. They lock.
*/
-static int drbg_bytes(unsigned char *out, int count)
+/*
+ * Allocates a new global DRBG on the secure heap (if enabled) and
+ * initializes it with default settings.
+ *
+ * Returns a pointer to the new DRBG instance on success, NULL on failure.
+ */
+static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
{
- int ret = 0;
- size_t chunk;
+ RAND_DRBG *drbg;
- CRYPTO_THREAD_write_lock(rand_drbg.lock);
- if (rand_drbg.state == DRBG_UNINITIALISED
- && RAND_DRBG_instantiate(&rand_drbg, NULL, 0) == 0)
+ drbg = OPENSSL_secure_zalloc(sizeof(RAND_DRBG));
+ if (drbg == NULL)
+ return NULL;
+
+ drbg->lock = CRYPTO_THREAD_lock_new();
+ if (drbg->lock == NULL) {
+ RANDerr(RAND_F_DRBG_SETUP, RAND_R_FAILED_TO_CREATE_LOCK);
goto err;
+ }
- for ( ; count > 0; count -= chunk, out += chunk) {
- chunk = count;
- if (chunk > rand_drbg.max_request)
- chunk = rand_drbg.max_request;
- ret = RAND_DRBG_generate(&rand_drbg, out, chunk, 0, NULL, 0);
- if (!ret)
- goto err;
+ if (RAND_DRBG_set(drbg,
+ RAND_DRBG_NID, RAND_DRBG_FLAG_CTR_USE_DF) != 1)
+ goto err;
+ if (RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
+ rand_drbg_cleanup_entropy, NULL, NULL) != 1)
+ goto err;
+
+ if (parent == NULL) {
+ drbg->reseed_interval = MASTER_RESEED_INTERVAL;
+ drbg->reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
+ } else {
+ drbg->parent = parent;
+ drbg->reseed_interval = SLAVE_RESEED_INTERVAL;
+ drbg->reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
}
- ret = 1;
+
+ /* enable seed propagation */
+ drbg->reseed_counter = 1;
+
+ /*
+ * Ignore instantiation error so support just-in-time instantiation.
+ *
+ * The state of the drbg will be checked in RAND_DRBG_generate() and
+ * an automatic recovery is attempted.
+ */
+ RAND_DRBG_instantiate(drbg,
+ (const unsigned char *) ossl_pers_string,
+ sizeof(ossl_pers_string) - 1);
+ return drbg;
err:
- CRYPTO_THREAD_unlock(rand_drbg.lock);
+ drbg_cleanup(drbg);
+ return NULL;
+}
+
+/*
+ * Initialize the global DRBGs on first use.
+ * Returns 1 on success, 0 on failure.
+ */
+DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
+{
+ /*
+ * ensure that libcrypto is initialized, otherwise the
+ * DRBG locks are not cleaned up properly
+ */
+ if (!OPENSSL_init_crypto(0, NULL))
+ return 0;
+
+ drbg_master = drbg_setup(NULL);
+ drbg_public = drbg_setup(drbg_master);
+ drbg_private = drbg_setup(drbg_master);
+
+ if (drbg_master == NULL || drbg_public == NULL || drbg_private == NULL)
+ return 0;
+
+ return 1;
+}
+
+/* Cleans up the given global DRBG */
+static void drbg_cleanup(RAND_DRBG *drbg)
+{
+ if (drbg != NULL) {
+ RAND_DRBG_uninstantiate(drbg);
+ CRYPTO_THREAD_lock_free(drbg->lock);
+ OPENSSL_secure_clear_free(drbg, sizeof(RAND_DRBG));
+ }
+}
+
+/* Clean up the global DRBGs before exit */
+void rand_drbg_cleanup_int(void)
+{
+ drbg_cleanup(drbg_private);
+ drbg_cleanup(drbg_public);
+ drbg_cleanup(drbg_master);
+
+ drbg_private = drbg_public = drbg_master = NULL;
+}
+
+/* Implements the default OpenSSL RAND_bytes() method */
+static int drbg_bytes(unsigned char *out, int count)
+{
+ int ret;
+ RAND_DRBG *drbg = RAND_DRBG_get0_public();
+
+ if (drbg == NULL)
+ return 0;
+
+ RAND_DRBG_lock(drbg);
+ ret = RAND_DRBG_bytes(drbg, out, count);
+ RAND_DRBG_unlock(drbg);
+
return ret;
}
+/* Implements the default OpenSSL RAND_add() method */
static int drbg_add(const void *buf, int num, double randomness)
{
- unsigned char *in = (unsigned char *)buf;
- unsigned char *out, *end;
+ int ret = 0;
+ RAND_DRBG *drbg = RAND_DRBG_get0_master();
- CRYPTO_THREAD_write_lock(rand_bytes.lock);
- out = &rand_bytes.buff[rand_bytes.curr];
- end = &rand_bytes.buff[rand_bytes.size];
+ if (drbg == NULL)
+ return 0;
- /* Copy whatever fits into the end of the buffer. */
- for ( ; --num >= 0 && out < end; rand_bytes.curr++)
- *out++ = *in++;
+ if (num < 0 || randomness < 0.0)
+ return 0;
- /* XOR any the leftover. */
- while (num > 0) {
- for (out = rand_bytes.buff; --num >= 0 && out < end; )
- *out++ ^= *in++;
+ if (randomness > (double)drbg->max_entropylen) {
+ /*
+ * The purpose of this check is to bound |randomness| by a
+ * relatively small value in order to prevent an integer
+ * overflow when multiplying by 8 in the rand_drbg_restart()
+ * call below.
+ */
+ return 0;
}
- CRYPTO_THREAD_unlock(rand_bytes.lock);
- return 1;
+ RAND_DRBG_lock(drbg);
+ ret = rand_drbg_restart(drbg, buf,
+ (size_t)(unsigned int)num,
+ (size_t)(8*randomness));
+ RAND_DRBG_unlock(drbg);
+
+ return ret;
}
+/* Implements the default OpenSSL RAND_seed() method */
static int drbg_seed(const void *buf, int num)
{
return drbg_add(buf, num, num);
}
+/* Implements the default OpenSSL RAND_status() method */
static int drbg_status(void)
{
int ret;
+ RAND_DRBG *drbg = RAND_DRBG_get0_master();
- CRYPTO_THREAD_write_lock(rand_drbg.lock);
- if (rand_drbg.state == DRBG_UNINITIALISED)
- RAND_DRBG_instantiate(&rand_drbg, NULL, 0);
- ret = rand_drbg.state == DRBG_READY ? 1 : 0;
- CRYPTO_THREAD_unlock(rand_drbg.lock);
+ if (drbg == NULL)
+ return 0;
+
+ RAND_DRBG_lock(drbg);
+ ret = drbg->state == DRBG_READY ? 1 : 0;
+ RAND_DRBG_unlock(drbg);
return ret;
}
-RAND_DRBG rand_drbg; /* The default global DRBG. */
-RAND_DRBG priv_drbg; /* The global private-key DRBG. */
+/*
+ * Get the master DRBG.
+ * Returns pointer to the DRBG on success, NULL on failure.
+ *
+ */
+RAND_DRBG *RAND_DRBG_get0_master(void)
+{
+ if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
+ return NULL;
+
+ return drbg_master;
+}
+
+/*
+ * Get the public DRBG.
+ * Returns pointer to the DRBG on success, NULL on failure.
+ */
+RAND_DRBG *RAND_DRBG_get0_public(void)
+{
+ if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
+ return NULL;
+
+ return drbg_public;
+}
+
+/*
+ * Get the private DRBG.
+ * Returns pointer to the DRBG on success, NULL on failure.
+ */
+RAND_DRBG *RAND_DRBG_get0_private(void)
+{
+ if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
+ return NULL;
+
+ return drbg_private;
+}
RAND_METHOD rand_meth = {
drbg_seed,
projects / openssl.git / blobdiff