diff options
Diffstat (limited to 'src/util/crypto_random.c')
| -rw-r--r-- | src/util/crypto_random.c | 51 |
1 files changed, 42 insertions, 9 deletions
diff --git a/src/util/crypto_random.c b/src/util/crypto_random.c index 35d3c41..b61d596 100644 --- a/src/util/crypto_random.c +++ b/src/util/crypto_random.c @@ -1,6 +1,6 @@ /* This file is part of GNUnet. - (C) 2001, 2002, 2003, 2004, 2005, 2006 Christian Grothoff (and other contributing authors) + (C) 2001, 2002, 2003, 2004, 2005, 2006, 2012 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published @@ -34,6 +34,14 @@ #define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall) + +/** + * GNUNET_YES if we are using a 'weak' (low-entropy) PRNG. + */ +static int weak_random; + + + /* TODO: ndurner, move this to plibc? */ /* The code is derived from glibc, obviously */ #if MINGW @@ -45,14 +53,22 @@ #endif #define RANDOM() glibc_weak_rand32() #define SRANDOM(s) glibc_weak_srand32(s) +#if defined(RAND_MAX) +#undef RAND_MAX +#endif +#define RAND_MAX 0x7fffffff /* Hopefully this is correct */ + + static int32_t glibc_weak_rand32_state = 1; + void glibc_weak_srand32 (int32_t s) { glibc_weak_rand32_state = s; } + int32_t glibc_weak_rand32 () { @@ -70,11 +86,12 @@ glibc_weak_rand32 () * @return number between 0 and 1. */ static double -weak_random () +get_weak_random () { return ((double) RANDOM () / RAND_MAX); } + /** * Seed a weak random generator. Only GNUNET_CRYPTO_QUALITY_WEAK-mode generator * can be seeded. @@ -87,6 +104,7 @@ GNUNET_CRYPTO_seed_weak_random (int32_t seed) SRANDOM (seed); } + /** * Produce a random value. * @@ -130,7 +148,7 @@ GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i) while (ret >= ul); return ret % i; case GNUNET_CRYPTO_QUALITY_WEAK: - ret = i * weak_random (); + ret = i * get_weak_random (); if (ret >= i) ret = i - 1; return ret; @@ -207,7 +225,7 @@ GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max) return ret % max; case GNUNET_CRYPTO_QUALITY_WEAK: - ret = max * weak_random (); + ret = max * get_weak_random (); if (ret >= max) ret = max - 1; return ret; @@ -217,6 +235,19 @@ GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max) return 0; } + +/** + * Check if we are using weak random number generation. + * + * @return GNUNET_YES if weak number generation is on + */ +int +GNUNET_CRYPTO_random_is_weak () +{ + return weak_random; +} + + /** * This function should only be called in testcases * where strong entropy gathering is not desired @@ -225,6 +256,7 @@ GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max) void GNUNET_CRYPTO_random_disable_entropy_gathering () { + weak_random = GNUNET_YES; gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0); } @@ -235,6 +267,7 @@ GNUNET_CRYPTO_random_disable_entropy_gathering () */ static struct GNUNET_OS_Process *genproc; + /** * Function called by libgcrypt whenever we are * blocked gathering entropy. @@ -253,7 +286,7 @@ entropy_generator (void *cls, const char *what, int printchar, int current, { if (genproc != NULL) { - if (0 != GNUNET_OS_process_kill (genproc, SIGTERM)) + if (0 != GNUNET_OS_process_kill (genproc, SIGKILL)) LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill"); GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc)); GNUNET_OS_process_destroy (genproc); @@ -271,7 +304,7 @@ entropy_generator (void *cls, const char *what, int printchar, int current, GNUNET_break (0); return; } - if (0 != GNUNET_OS_process_kill (genproc, SIGTERM)) + if (0 != GNUNET_OS_process_kill (genproc, SIGKILL)) LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill"); GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc)); GNUNET_OS_process_destroy (genproc); @@ -280,7 +313,7 @@ entropy_generator (void *cls, const char *what, int printchar, int current, LOG (GNUNET_ERROR_TYPE_INFO, _("Starting `%s' process to generate entropy\n"), "find"); genproc = - GNUNET_OS_start_process (GNUNET_NO, + GNUNET_OS_start_process (GNUNET_NO, 0, NULL, NULL, "sh", "sh", "-c", "exec find / -mount -type f -exec cp {} /dev/null \\; 2>/dev/null", NULL); @@ -302,12 +335,12 @@ killfind () void __attribute__ ((constructor)) GNUNET_CRYPTO_random_init () { gcry_control (GCRYCTL_DISABLE_SECMEM, 0); - if (!gcry_check_version (GCRYPT_VERSION)) + if (!gcry_check_version (NEED_LIBGCRYPT_VERSION)) { FPRINTF (stderr, _ ("libgcrypt has not the expected version (version %s is required).\n"), - GCRYPT_VERSION); + NEED_LIBGCRYPT_VERSION); GNUNET_abort (); } #ifdef GCRYCTL_INITIALIZATION_FINISHED |