Mercurial > dropbear
view libtomcrypt/src/prngs/rng_get_bytes.c @ 1938:77bc00dcc19f default tip main master
Bump version to 2022.82
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Fri, 01 Apr 2022 14:43:27 +0800 |
parents | 6dba84798cd5 |
children |
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. */ #include "tomcrypt.h" #ifdef LTC_RNG_GET_BYTES /** @file rng_get_bytes.c portable way to get secure random bits to feed a PRNG (Tom St Denis) */ #if defined(LTC_DEVRANDOM) && !defined(_WIN32) /* on *NIX read /dev/random */ static unsigned long _rng_nix(unsigned char *buf, unsigned long len, void (*callback)(void)) { #ifdef LTC_NO_FILE LTC_UNUSED_PARAM(callback); LTC_UNUSED_PARAM(buf); LTC_UNUSED_PARAM(len); return 0; #else FILE *f; unsigned long x; LTC_UNUSED_PARAM(callback); #ifdef LTC_TRY_URANDOM_FIRST f = fopen("/dev/urandom", "rb"); if (f == NULL) #endif /* LTC_TRY_URANDOM_FIRST */ f = fopen("/dev/random", "rb"); if (f == NULL) { return 0; } /* disable buffering */ if (setvbuf(f, NULL, _IONBF, 0) != 0) { fclose(f); return 0; } x = (unsigned long)fread(buf, 1, (size_t)len, f); fclose(f); return x; #endif /* LTC_NO_FILE */ } #endif /* LTC_DEVRANDOM */ #if !defined(_WIN32_WCE) #define ANSI_RNG static unsigned long _rng_ansic(unsigned char *buf, unsigned long len, void (*callback)(void)) { clock_t t1; int l, acc, bits, a, b; l = len; bits = 8; acc = a = b = 0; while (len--) { if (callback != NULL) callback(); while (bits--) { do { t1 = XCLOCK(); while (t1 == XCLOCK()) a ^= 1; t1 = XCLOCK(); while (t1 == XCLOCK()) b ^= 1; } while (a == b); acc = (acc << 1) | a; } *buf++ = acc; acc = 0; bits = 8; } return l; } #endif /* Try the Microsoft CSP */ #if defined(_WIN32) || defined(_WIN32_WCE) #ifndef _WIN32_WINNT #define _WIN32_WINNT 0x0400 #endif #ifdef _WIN32_WCE #define UNDER_CE #define ARM #endif #define WIN32_LEAN_AND_MEAN #include <windows.h> #include <wincrypt.h> static unsigned long _rng_win32(unsigned char *buf, unsigned long len, void (*callback)(void)) { HCRYPTPROV hProv = 0; LTC_UNUSED_PARAM(callback); if (!CryptAcquireContext(&hProv, NULL, MS_DEF_PROV, PROV_RSA_FULL, (CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET)) && !CryptAcquireContext (&hProv, NULL, MS_DEF_PROV, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET | CRYPT_NEWKEYSET)) return 0; if (CryptGenRandom(hProv, len, buf) == TRUE) { CryptReleaseContext(hProv, 0); return len; } else { CryptReleaseContext(hProv, 0); return 0; } } #endif /* WIN32 */ /** Read the system RNG @param out Destination @param outlen Length desired (octets) @param callback Pointer to void function to act as "callback" when RNG is slow. This can be NULL @return Number of octets read */ unsigned long rng_get_bytes(unsigned char *out, unsigned long outlen, void (*callback)(void)) { unsigned long x; LTC_ARGCHK(out != NULL); #ifdef LTC_PRNG_ENABLE_LTC_RNG if (ltc_rng) { x = ltc_rng(out, outlen, callback); if (x != 0) { return x; } } #endif #if defined(_WIN32) || defined(_WIN32_WCE) x = _rng_win32(out, outlen, callback); if (x != 0) { return x; } #elif defined(LTC_DEVRANDOM) x = _rng_nix(out, outlen, callback); if (x != 0) { return x; } #endif #ifdef ANSI_RNG x = _rng_ansic(out, outlen, callback); if (x != 0) { return x; } #endif return 0; } #endif /* #ifdef LTC_RNG_GET_BYTES */ /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */