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-rw-r--r--util-src/crand.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/util-src/crand.c b/util-src/crand.c
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+++ b/util-src/crand.c
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+/* Prosody IM
+-- Copyright (C) 2008-2017 Matthew Wild
+-- Copyright (C) 2008-2017 Waqas Hussain
+-- Copyright (C) 2016-2017 Kim Alvefur
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+*/
+
+/*
+* crand.c
+* C PRNG interface
+*
+* The purpose of this module is to provide access to a PRNG in
+* environments without /dev/urandom
+*
+* Caution! This has not been extensively tested.
+*
+*/
+
+#define _DEFAULT_SOURCE
+
+#include "lualib.h"
+#include "lauxlib.h"
+
+#include <string.h>
+#include <errno.h>
+
+#if defined(WITH_GETRANDOM)
+
+#if ! __GLIBC_PREREQ(2,25)
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#ifndef SYS_getrandom
+#error getrandom() requires Linux 3.17 or later
+#endif
+
+/* This wasn't present before glibc 2.25 */
+int getrandom(void *buf, size_t buflen, unsigned int flags) {
+ return syscall(SYS_getrandom, buf, buflen, flags);
+}
+#else
+#include <sys/random.h>
+#endif
+
+#elif defined(WITH_ARC4RANDOM)
+#include <stdlib.h>
+#elif defined(WITH_OPENSSL)
+#include <openssl/rand.h>
+#else
+#error util.crand compiled without a random source
+#endif
+
+int Lrandom(lua_State *L) {
+ int ret = 0;
+ size_t len = (size_t)luaL_checkinteger(L, 1);
+ void *buf = lua_newuserdata(L, len);
+
+#if defined(WITH_GETRANDOM)
+ /*
+ * This acts like a read from /dev/urandom with the exception that it
+ * *does* block if the entropy pool is not yet initialized.
+ */
+ ret = getrandom(buf, len, 0);
+
+ if(ret < 0) {
+ lua_pushstring(L, strerror(errno));
+ return lua_error(L);
+ }
+
+#elif defined(WITH_ARC4RANDOM)
+ arc4random_buf(buf, len);
+ ret = len;
+#elif defined(WITH_OPENSSL)
+ if(!RAND_status()) {
+ lua_pushliteral(L, "OpenSSL PRNG not seeded");
+ return lua_error(L);
+ }
+
+ ret = RAND_bytes(buf, len);
+
+ if(ret == 1) {
+ ret = len;
+ } else {
+ /* TODO ERR_get_error() */
+ lua_pushstring(L, "RAND_bytes() failed");
+ return lua_error(L);
+ }
+
+#endif
+
+ lua_pushlstring(L, buf, ret);
+ return 1;
+}
+
+int luaopen_util_crand(lua_State *L) {
+#if (LUA_VERSION_NUM > 501)
+ luaL_checkversion(L);
+#endif
+
+ lua_createtable(L, 0, 2);
+ lua_pushcfunction(L, Lrandom);
+ lua_setfield(L, -2, "bytes");
+
+#if defined(WITH_GETRANDOM)
+ lua_pushstring(L, "Linux");
+#elif defined(WITH_ARC4RANDOM)
+ lua_pushstring(L, "arc4random()");
+#elif defined(WITH_OPENSSL)
+ lua_pushstring(L, "OpenSSL");
+#endif
+ lua_setfield(L, -2, "_source");
+
+ return 1;
+}
+