diff options
Diffstat (limited to 'lib/random.c')
| -rw-r--r-- | lib/random.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/lib/random.c b/lib/random.c new file mode 100644 index 0000000..f1abe74 --- /dev/null +++ b/lib/random.c @@ -0,0 +1,196 @@ +/* + * Copyright (C) 2008-2012 Free Software Foundation, Inc. + * + * Author: Nikos Mavrogiannopoulos + * + * This file is part of GnuTLS. + * + * The GnuTLS is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/> + * + */ + +/* This file handles all the internal functions that cope with random data. + */ + +#include "gnutls_int.h" +#include "errors.h" +#include <random.h> +#include "locks.h" +#include <fips.h> + +#include "gthreads.h" + +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) +extern gnutls_crypto_rnd_st _gnutls_fuzz_rnd_ops; +#endif + +/* Per thread context of random generator, and a flag to indicate initialization */ +static _Thread_local void *gnutls_rnd_ctx; +static _Thread_local unsigned rnd_initialized = 0; + +struct rnd_ctx_list_st { + void *ctx; + struct rnd_ctx_list_st *next; +}; + +/* A global list of all allocated contexts - to be + * used during deinitialization. */ +GNUTLS_STATIC_MUTEX(gnutls_rnd_ctx_list_mutex); +static struct rnd_ctx_list_st *head = NULL; + +static int append(void *ctx) +{ + struct rnd_ctx_list_st *e = gnutls_malloc(sizeof(*e)); + + if (e == NULL) + return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR); + + e->ctx = ctx; + e->next = head; + + head = e; + + return 0; +} + +inline static int _gnutls_rnd_init(void) +{ + if (unlikely(!rnd_initialized)) { + int ret; + + if (_gnutls_rnd_ops.init == NULL) { + rnd_initialized = 1; + return 0; + } + + if (_gnutls_rnd_ops.init(&gnutls_rnd_ctx) < 0) { + gnutls_assert(); + return GNUTLS_E_RANDOM_FAILED; + } + + ret = gnutls_static_mutex_lock(&gnutls_rnd_ctx_list_mutex); + if (ret < 0) { + return gnutls_assert_val(ret); + } + ret = append(gnutls_rnd_ctx); + (void)gnutls_static_mutex_unlock(&gnutls_rnd_ctx_list_mutex); + if (ret < 0) { + gnutls_assert(); + _gnutls_rnd_ops.deinit(gnutls_rnd_ctx); + return ret; + } + + rnd_initialized = 1; + } + return 0; +} + +int _gnutls_rnd_preinit(void) +{ + int ret; + +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) +# warning Insecure PRNG is enabled + ret = gnutls_crypto_rnd_register(100, &_gnutls_fuzz_rnd_ops); + if (ret < 0) + return ret; + +#elif defined(ENABLE_FIPS140) + /* The FIPS140 random generator is only enabled when we are compiled + * with FIPS support, _and_ the system is in FIPS installed state. + */ + if (_gnutls_fips_mode_enabled() != 0) { + ret = gnutls_crypto_rnd_register(100, &_gnutls_fips_rnd_ops); + if (ret < 0) + return ret; + } +#endif + + ret = _rnd_system_entropy_init(); + if (ret < 0) { + gnutls_assert(); + return GNUTLS_E_RANDOM_FAILED; + } + + return 0; +} + +void _gnutls_rnd_deinit(void) +{ + if (_gnutls_rnd_ops.deinit != NULL) { + struct rnd_ctx_list_st *e = head, *next; + + while(e != NULL) { + next = e->next; + _gnutls_rnd_ops.deinit(e->ctx); + gnutls_free(e); + e = next; + } + head = NULL; + } + + rnd_initialized = 0; + _rnd_system_entropy_deinit(); + + return; +} + +/** + * gnutls_rnd: + * @level: a security level + * @data: place to store random bytes + * @len: The requested size + * + * This function will generate random data and store it to output + * buffer. The value of @level should be one of %GNUTLS_RND_NONCE, + * %GNUTLS_RND_RANDOM and %GNUTLS_RND_KEY. See the manual and + * %gnutls_rnd_level_t for detailed information. + * + * This function is thread-safe and also fork-safe. + * + * Returns: Zero on success, or a negative error code on error. + * + * Since: 2.12.0 + **/ +int gnutls_rnd(gnutls_rnd_level_t level, void *data, size_t len) +{ + int ret; + FAIL_IF_LIB_ERROR; + + if (unlikely((ret=_gnutls_rnd_init()) < 0)) + return gnutls_assert_val(ret); + + if (likely(len > 0)) { + return _gnutls_rnd_ops.rnd(gnutls_rnd_ctx, level, data, + len); + } + return 0; +} + +/** + * gnutls_rnd_refresh: + * + * This function refreshes the random generator state. + * That is the current precise time, CPU usage, and + * other values are input into its state. + * + * On a slower rate input from /dev/urandom is mixed too. + * + * Since: 3.1.7 + **/ +void gnutls_rnd_refresh(void) +{ + if (rnd_initialized && _gnutls_rnd_ops.rnd_refresh) + _gnutls_rnd_ops.rnd_refresh(gnutls_rnd_ctx); +} |