f61f62ea13
The functions RAND_bytes() and RAND_priv_bytes() are now both based on a common implementation using RAND_DRBG_bytes() (if the default OpenSSL rand method is active). This not only simplifies the code but also has the advantage that additional input from a high precision timer is added on every generate call if the timer is available. Reviewed-by: Kurt Roeckx <kurt@roeckx.be> (Merged from https://github.com/openssl/openssl/pull/5251)
893 lines
26 KiB
C
893 lines
26 KiB
C
/*
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* Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <string.h>
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#include <openssl/crypto.h>
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#include <openssl/err.h>
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#include <openssl/rand.h>
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#include "rand_lcl.h"
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#include "internal/thread_once.h"
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#include "internal/rand_int.h"
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/*
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* Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
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* The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG.
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*
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* The OpenSSL model is to have new and free functions, and that new
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* does all initialization. That is not the NIST model, which has
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* instantiation and un-instantiate, and re-use within a new/free
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* lifecycle. (No doubt this comes from the desire to support hardware
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* DRBG, where allocation of resources on something like an HSM is
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* a much bigger deal than just re-setting an allocated resource.)
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*/
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/*
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* THE THREE SHARED DRBGs
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*
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* There are three shared DRBGs (master, public and private), which are
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* accessed concurrently by all threads.
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*
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* THE MASTER DRBG
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*
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* Not used directly by the application, only for reseeding the two other
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* DRBGs. It reseeds itself by pulling either randomness from os entropy
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* sources or by consuming randomnes which was added by RAND_add()
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*/
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static RAND_DRBG *drbg_master;
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/*
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* THE PUBLIC DRBG
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*
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* Used by default for generating random bytes using RAND_bytes().
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*/
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static RAND_DRBG *drbg_public;
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/*
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* THE PRIVATE DRBG
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*
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* Used by default for generating private keys using RAND_priv_bytes()
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*/
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static RAND_DRBG *drbg_private;
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/*+
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* DRBG HIERARCHY
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*
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* In addition there are DRBGs, which are not shared, but used only by a
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* single thread at every time, for example the DRBGs which are owned by
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* an SSL context. All DRBGs are organized in a hierarchical fashion
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* with the <master> DRBG as root.
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*
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* This gives the following overall picture:
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*
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* <os entropy sources>
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* |
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* RAND_add() ==> <master> \
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* / \ | shared DRBGs (with locking)
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* <public> <private> /
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* |
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* <ssl> owned by an SSL context
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*
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* AUTOMATIC RESEEDING
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*
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* Before satisfying a generate request, a DRBG reseeds itself automatically,
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* if one of the following two conditions holds:
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*
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* - the number of generate requests since the last reseeding exceeds a
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* certain threshold, the so called |reseed_interval|. This behaviour
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* can be disabled by setting the |reseed_interval| to 0.
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*
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* - the time elapsed since the last reseeding exceeds a certain time
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* interval, the so called |reseed_time_interval|. This behaviour
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* can be disabled by setting the |reseed_time_interval| to 0.
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*
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* MANUAL RESEEDING
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*
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* For the three shared DRBGs (and only for these) there is another way to
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* reseed them manually by calling RAND_seed() (or RAND_add() with a positive
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* |randomness| argument). This will immediately reseed the <master> DRBG.
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* The <public> and <private> DRBG will detect this on their next generate
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* call and reseed, pulling randomness from <master>.
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*/
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/* NIST SP 800-90A DRBG recommends the use of a personalization string. */
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static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG";
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static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT;
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static RAND_DRBG *drbg_setup(RAND_DRBG *parent);
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static void drbg_cleanup(RAND_DRBG *drbg);
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/*
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* Set/initialize |drbg| to be of type |nid|, with optional |flags|.
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*
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* Returns 1 on success, 0 on failure.
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*/
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int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags)
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{
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int ret = 1;
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drbg->state = DRBG_UNINITIALISED;
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drbg->flags = flags;
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drbg->nid = nid;
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switch (nid) {
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default:
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RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
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return 0;
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case 0:
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/* Uninitialized; that's okay. */
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return 1;
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case NID_aes_128_ctr:
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case NID_aes_192_ctr:
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case NID_aes_256_ctr:
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ret = drbg_ctr_init(drbg);
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break;
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}
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if (ret == 0)
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RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
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return ret;
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}
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/*
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* Allocate memory and initialize a new DRBG. The |parent|, if not
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* NULL, will be used to auto-seed this RAND_DRBG as needed.
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*
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* Returns a pointer to the new DRBG instance on success, NULL on failure.
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*/
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RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
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{
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RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
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if (drbg == NULL) {
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RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
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goto err;
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}
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drbg->fork_count = rand_fork_count;
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drbg->parent = parent;
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if (RAND_DRBG_set(drbg, type, flags) == 0)
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goto err;
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if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
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rand_drbg_cleanup_entropy,
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NULL, NULL))
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goto err;
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return drbg;
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err:
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OPENSSL_free(drbg);
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return NULL;
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}
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/*
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* Uninstantiate |drbg| and free all memory.
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*/
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void RAND_DRBG_free(RAND_DRBG *drbg)
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{
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if (drbg == NULL)
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return;
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if (drbg->meth != NULL)
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drbg->meth->uninstantiate(drbg);
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CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
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OPENSSL_clear_free(drbg, sizeof(*drbg));
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}
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/*
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* Instantiate |drbg|, after it has been initialized. Use |pers| and
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* |perslen| as prediction-resistance input.
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*
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* Requires that drbg->lock is already locked for write, if non-null.
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*
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* Returns 1 on success, 0 on failure.
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*/
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int RAND_DRBG_instantiate(RAND_DRBG *drbg,
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const unsigned char *pers, size_t perslen)
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{
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unsigned char *nonce = NULL, *entropy = NULL;
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size_t noncelen = 0, entropylen = 0;
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if (perslen > drbg->max_perslen) {
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RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
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RAND_R_PERSONALISATION_STRING_TOO_LONG);
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goto end;
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}
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if (drbg->meth == NULL)
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{
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RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
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RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
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goto end;
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}
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if (drbg->state != DRBG_UNINITIALISED) {
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RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
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drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
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: RAND_R_ALREADY_INSTANTIATED);
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goto end;
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}
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drbg->state = DRBG_ERROR;
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if (drbg->get_entropy != NULL)
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entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
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drbg->min_entropylen, drbg->max_entropylen);
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if (entropylen < drbg->min_entropylen
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|| entropylen > drbg->max_entropylen) {
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RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
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goto end;
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}
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if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) {
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noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
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drbg->min_noncelen, drbg->max_noncelen);
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if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
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RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
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RAND_R_ERROR_RETRIEVING_NONCE);
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goto end;
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}
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}
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if (!drbg->meth->instantiate(drbg, entropy, entropylen,
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nonce, noncelen, pers, perslen)) {
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RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
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goto end;
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}
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drbg->state = DRBG_READY;
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drbg->generate_counter = 0;
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drbg->reseed_time = time(NULL);
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if (drbg->reseed_counter > 0) {
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if (drbg->parent == NULL)
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drbg->reseed_counter++;
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else
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drbg->reseed_counter = drbg->parent->reseed_counter;
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}
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end:
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if (entropy != NULL && drbg->cleanup_entropy != NULL)
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drbg->cleanup_entropy(drbg, entropy, entropylen);
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if (nonce != NULL && drbg->cleanup_nonce!= NULL )
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drbg->cleanup_nonce(drbg, nonce, noncelen);
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if (drbg->pool != NULL) {
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if (drbg->state == DRBG_READY) {
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RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
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RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
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drbg->state = DRBG_ERROR;
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}
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RAND_POOL_free(drbg->pool);
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drbg->pool = NULL;
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}
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if (drbg->state == DRBG_READY)
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return 1;
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return 0;
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}
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/*
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* Uninstantiate |drbg|. Must be instantiated before it can be used.
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*
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* Requires that drbg->lock is already locked for write, if non-null.
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*
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* Returns 1 on success, 0 on failure.
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*/
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int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
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{
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if (drbg->meth == NULL)
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{
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RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
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RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
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return 0;
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}
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/* Clear the entire drbg->ctr struct, then reset some important
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* members of the drbg->ctr struct (e.g. keysize, df_ks) to their
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* initial values.
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*/
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drbg->meth->uninstantiate(drbg);
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return RAND_DRBG_set(drbg, drbg->nid, drbg->flags);
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}
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/*
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* Reseed |drbg|, mixing in the specified data
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*
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* Requires that drbg->lock is already locked for write, if non-null.
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*
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* Returns 1 on success, 0 on failure.
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*/
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int RAND_DRBG_reseed(RAND_DRBG *drbg,
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const unsigned char *adin, size_t adinlen)
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{
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unsigned char *entropy = NULL;
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size_t entropylen = 0;
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if (drbg->state == DRBG_ERROR) {
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RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
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return 0;
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}
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if (drbg->state == DRBG_UNINITIALISED) {
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RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
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return 0;
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}
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if (adin == NULL)
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adinlen = 0;
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else if (adinlen > drbg->max_adinlen) {
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RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
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return 0;
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}
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drbg->state = DRBG_ERROR;
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if (drbg->get_entropy != NULL)
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entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
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drbg->min_entropylen, drbg->max_entropylen);
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if (entropylen < drbg->min_entropylen
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|| entropylen > drbg->max_entropylen) {
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RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
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goto end;
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}
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if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
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goto end;
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drbg->state = DRBG_READY;
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drbg->generate_counter = 0;
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drbg->reseed_time = time(NULL);
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if (drbg->reseed_counter > 0) {
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if (drbg->parent == NULL)
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drbg->reseed_counter++;
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else
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drbg->reseed_counter = drbg->parent->reseed_counter;
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}
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end:
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if (entropy != NULL && drbg->cleanup_entropy != NULL)
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drbg->cleanup_entropy(drbg, entropy, entropylen);
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if (drbg->state == DRBG_READY)
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return 1;
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return 0;
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}
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/*
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* Restart |drbg|, using the specified entropy or additional input
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*
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* Tries its best to get the drbg instantiated by all means,
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* regardless of its current state.
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*
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* Optionally, a |buffer| of |len| random bytes can be passed,
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* which is assumed to contain at least |entropy| bits of entropy.
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*
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* If |entropy| > 0, the buffer content is used as entropy input.
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*
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* If |entropy| == 0, the buffer content is used as additional input
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*
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* Returns 1 on success, 0 on failure.
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*
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* This function is used internally only.
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*/
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int rand_drbg_restart(RAND_DRBG *drbg,
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const unsigned char *buffer, size_t len, size_t entropy)
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{
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int reseeded = 0;
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const unsigned char *adin = NULL;
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size_t adinlen = 0;
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if (drbg->pool != NULL) {
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RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
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RAND_POOL_free(drbg->pool);
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drbg->pool = NULL;
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}
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if (buffer != NULL) {
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if (entropy > 0) {
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if (drbg->max_entropylen < len) {
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RANDerr(RAND_F_RAND_DRBG_RESTART,
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RAND_R_ENTROPY_INPUT_TOO_LONG);
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return 0;
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}
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if (entropy > 8 * len) {
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RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
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return 0;
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}
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/* will be picked up by the rand_drbg_get_entropy() callback */
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drbg->pool = RAND_POOL_new(entropy, len, len);
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if (drbg->pool == NULL)
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return 0;
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RAND_POOL_add(drbg->pool, buffer, len, entropy);
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} else {
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if (drbg->max_adinlen < len) {
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RANDerr(RAND_F_RAND_DRBG_RESTART,
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RAND_R_ADDITIONAL_INPUT_TOO_LONG);
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return 0;
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}
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adin = buffer;
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adinlen = len;
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}
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}
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/* repair error state */
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if (drbg->state == DRBG_ERROR)
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RAND_DRBG_uninstantiate(drbg);
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/* repair uninitialized state */
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if (drbg->state == DRBG_UNINITIALISED) {
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/* reinstantiate drbg */
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RAND_DRBG_instantiate(drbg,
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(const unsigned char *) ossl_pers_string,
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sizeof(ossl_pers_string) - 1);
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/* already reseeded. prevent second reseeding below */
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reseeded = (drbg->state == DRBG_READY);
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}
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/* refresh current state if entropy or additional input has been provided */
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if (drbg->state == DRBG_READY) {
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if (adin != NULL) {
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/*
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* mix in additional input without reseeding
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*
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* Similar to RAND_DRBG_reseed(), but the provided additional
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* data |adin| is mixed into the current state without pulling
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* entropy from the trusted entropy source using get_entropy().
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* This is not a reseeding in the strict sense of NIST SP 800-90A.
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*/
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drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
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} else if (reseeded == 0) {
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/* do a full reseeding if it has not been done yet above */
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RAND_DRBG_reseed(drbg, NULL, 0);
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}
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}
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/* check whether a given entropy pool was cleared properly during reseed */
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if (drbg->pool != NULL) {
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drbg->state = DRBG_ERROR;
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RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
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RAND_POOL_free(drbg->pool);
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drbg->pool = NULL;
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return 0;
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}
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return drbg->state == DRBG_READY;
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}
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/*
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* Generate |outlen| bytes into the buffer at |out|. Reseed if we need
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* to or if |prediction_resistance| is set. Additional input can be
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* sent in |adin| and |adinlen|.
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*
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* Requires that drbg->lock is already locked for write, if non-null.
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*
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* Returns 1 on success, 0 on failure.
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*
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*/
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int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
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int prediction_resistance,
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const unsigned char *adin, size_t adinlen)
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{
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int reseed_required = 0;
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if (drbg->state != DRBG_READY) {
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/* try to recover from previous errors */
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rand_drbg_restart(drbg, NULL, 0, 0);
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|
|
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_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;
|
|
reseed_required = 1;
|
|
}
|
|
|
|
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 (reseed_required || prediction_resistance) {
|
|
if (!RAND_DRBG_reseed(drbg, adin, adinlen)) {
|
|
RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
|
|
return 0;
|
|
}
|
|
adin = NULL;
|
|
adinlen = 0;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
drbg->generate_counter++;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* 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 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 = 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, unsigned int interval)
|
|
{
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Get and set the EXDATA
|
|
*/
|
|
int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
|
|
{
|
|
return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
|
|
}
|
|
|
|
void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
|
|
{
|
|
return CRYPTO_get_ex_data(&drbg->ex_data, idx);
|
|
}
|
|
|
|
|
|
/*
|
|
* The following functions provide a RAND_METHOD that works on the
|
|
* global DRBG. They lock.
|
|
*/
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
RAND_DRBG *drbg;
|
|
|
|
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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
/* 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:
|
|
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;
|
|
|
|
CRYPTO_THREAD_write_lock(drbg->lock);
|
|
ret = RAND_DRBG_bytes(drbg, out, count);
|
|
CRYPTO_THREAD_unlock(drbg->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Implements the default OpenSSL RAND_add() method */
|
|
static int drbg_add(const void *buf, int num, double randomness)
|
|
{
|
|
int ret = 0;
|
|
RAND_DRBG *drbg = RAND_DRBG_get0_master();
|
|
|
|
if (drbg == NULL)
|
|
return 0;
|
|
|
|
if (num < 0 || randomness < 0.0)
|
|
return 0;
|
|
|
|
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_write_lock(drbg->lock);
|
|
ret = rand_drbg_restart(drbg, buf,
|
|
(size_t)(unsigned int)num,
|
|
(size_t)(8*randomness));
|
|
CRYPTO_THREAD_unlock(drbg->lock);
|
|
|
|
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();
|
|
|
|
if (drbg == NULL)
|
|
return 0;
|
|
|
|
CRYPTO_THREAD_write_lock(drbg->lock);
|
|
ret = drbg->state == DRBG_READY ? 1 : 0;
|
|
CRYPTO_THREAD_unlock(drbg->lock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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,
|
|
drbg_bytes,
|
|
NULL,
|
|
drbg_add,
|
|
drbg_bytes,
|
|
drbg_status
|
|
};
|
|
|
|
RAND_METHOD *RAND_OpenSSL(void)
|
|
{
|
|
return &rand_meth;
|
|
}
|