X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fcrypto_random.c;h=c74d60f4f8bc7ad2767e7e05d4a8395ed2d99ad0;hb=83b19539f4d322b43683f5838b72e9ec2c8e6073;hp=5d85d1daa1376d5b2f96b5f2ba146acd69e8664a;hpb=652e89b59ed2207c2c12172fdabcd6e659995c81;p=oweals%2Fgnunet.git diff --git a/src/util/crypto_random.c b/src/util/crypto_random.c index 5d85d1daa..c74d60f4f 100644 --- a/src/util/crypto_random.c +++ b/src/util/crypto_random.c @@ -27,8 +27,25 @@ #include "platform.h" #include "gnunet_common.h" #include "gnunet_crypto_lib.h" +#include "gnunet_os_lib.h" #include +#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__) + +#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall) + +/** + * Create a cryptographically weak pseudo-random number in the interval of 0 to 1. + * + * @return number between 0 and 1. + */ +static double +weak_random () +{ + return ((double) RANDOM () / RAND_MAX); +} + + /** * Produce a random value. * @@ -43,27 +60,43 @@ GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i) static unsigned int invokeCount; #endif uint32_t ret; + uint32_t ul; GNUNET_assert (i > 0); - if (mode == GNUNET_CRYPTO_QUALITY_STRONG) - { - /* see http://lists.gnupg.org/pipermail/gcrypt-devel/2004-May/000613.html */ + switch (mode) + { + case GNUNET_CRYPTO_QUALITY_STRONG: + /* see http://lists.gnupg.org/pipermail/gcrypt-devel/2004-May/000613.html */ #ifdef gcry_fast_random_poll - if ((invokeCount++ % 256) == 0) - gcry_fast_random_poll (); + if ((invokeCount++ % 256) == 0) + gcry_fast_random_poll (); #endif - gcry_randomize ((unsigned char *) &ret, - sizeof (uint32_t), GCRY_STRONG_RANDOM); - return ret % i; + ul = UINT32_MAX - (UINT32_MAX % i); + do + { + gcry_randomize ((unsigned char *) &ret, sizeof (uint32_t), + GCRY_STRONG_RANDOM); } - else + while (ret >= ul); + return ret % i; + case GNUNET_CRYPTO_QUALITY_NONCE: + ul = UINT32_MAX - (UINT32_MAX % i); + do { - ret = i * ((double) RANDOM () / RAND_MAX); - if (ret >= i) - ret = i - 1; - return ret; + gcry_create_nonce (&ret, sizeof (ret)); } + while (ret >= ul); + return ret % i; + case GNUNET_CRYPTO_QUALITY_WEAK: + ret = i * weak_random (); + if (ret >= i) + ret = i - 1; + return ret; + default: + GNUNET_assert (0); + } + return 0; } @@ -87,13 +120,13 @@ GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n) ret = GNUNET_malloc (n * sizeof (unsigned int)); for (i = 0; i < n; i++) ret[i] = i; - for (i = 0; i < n; i++) - { - x = GNUNET_CRYPTO_random_u32 (mode, n); - tmp = ret[x]; - ret[x] = ret[i]; - ret[i] = tmp; - } + for (i = n - 1; i > 0; i--) + { + x = GNUNET_CRYPTO_random_u32 (mode, i + 1); + tmp = ret[x]; + ret[x] = ret[i]; + ret[i] = tmp; + } return ret; } @@ -109,21 +142,38 @@ uint64_t GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max) { uint64_t ret; + uint64_t ul; GNUNET_assert (max > 0); - if (mode == GNUNET_CRYPTO_QUALITY_STRONG) + switch (mode) + { + case GNUNET_CRYPTO_QUALITY_STRONG: + ul = UINT64_MAX - (UINT64_MAX % max); + do { - gcry_randomize ((unsigned char *) &ret, - sizeof (uint64_t), GCRY_STRONG_RANDOM); - return ret % max; + gcry_randomize ((unsigned char *) &ret, sizeof (uint64_t), + GCRY_STRONG_RANDOM); } - else + while (ret >= ul); + return ret % max; + case GNUNET_CRYPTO_QUALITY_NONCE: + ul = UINT64_MAX - (UINT64_MAX % max); + do { - ret = max * ((double) RANDOM () / RAND_MAX); - if (ret >= max) - ret = max - 1; - return ret; + gcry_create_nonce (&ret, sizeof (ret)); } + while (ret >= ul); + + return ret % max; + case GNUNET_CRYPTO_QUALITY_WEAK: + ret = max * weak_random (); + if (ret >= max) + ret = max - 1; + return ret; + default: + GNUNET_assert (0); + } + return 0; } /** @@ -137,12 +187,102 @@ GNUNET_CRYPTO_random_disable_entropy_gathering () gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0); } + /** - * Initializer + * Process ID of the "find" process that we use for + * entropy gathering. */ -void __attribute__ ((constructor)) GNUNET_util_random_init () +static struct GNUNET_OS_Process *genproc; + +/** + * Function called by libgcrypt whenever we are + * blocked gathering entropy. + */ +static void +entropy_generator (void *cls, const char *what, int printchar, int current, + int total) +{ + unsigned long code; + enum GNUNET_OS_ProcessStatusType type; + int ret; + + if (0 != strcmp (what, "need_entropy")) + return; + if (current == total) + { + if (genproc != NULL) + { + if (0 != GNUNET_OS_process_kill (genproc, SIGTERM)) + LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill"); + GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc)); + GNUNET_OS_process_close (genproc); + genproc = NULL; + } + return; + } + if (genproc != NULL) + { + ret = GNUNET_OS_process_status (genproc, &type, &code); + if (ret == GNUNET_NO) + return; /* still running */ + if (ret == GNUNET_SYSERR) + { + GNUNET_break (0); + return; + } + if (0 != GNUNET_OS_process_kill (genproc, SIGTERM)) + LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill"); + GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc)); + GNUNET_OS_process_close (genproc); + genproc = NULL; + } + LOG (GNUNET_ERROR_TYPE_INFO, _("Starting `%s' process to generate entropy\n"), + "find"); + genproc = + GNUNET_OS_start_process (NULL, NULL, "sh", "sh", "-c", + "exec find / -mount -type f -exec cp {} /dev/null \\; 2>/dev/null", + NULL); +} + + +static void +killfind () +{ + if (genproc != NULL) + { + GNUNET_OS_process_kill (genproc, SIGKILL); + GNUNET_OS_process_close (genproc); + genproc = NULL; + } +} + + +void __attribute__ ((constructor)) GNUNET_CRYPTO_random_init () +{ + gcry_control (GCRYCTL_DISABLE_SECMEM, 0); + if (!gcry_check_version (GCRYPT_VERSION)) + { + fprintf (stderr, + _ + ("libgcrypt has not the expected version (version %s is required).\n"), + GCRYPT_VERSION); + abort (); + } +#ifdef gcry_fast_random_poll + gcry_fast_random_poll (); +#endif + gcry_set_progress_handler (&entropy_generator, NULL); + atexit (&killfind); + SRANDOM (time (NULL) ^ + GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX)); +} + + +void __attribute__ ((destructor)) GNUNET_CRYPTO_random_fini () { - SRANDOM (time (NULL)); + gcry_set_progress_handler (NULL, NULL); } + + /* end of crypto_random.c */