util.crand: C binding to one of OpenSSL, Linux getrandom() or OpenBSD arc4random...

diff --git a/configure b/configure
index b64c265410cd555c7273a87abfdfc9ef5c286678..77aa132920646ff73328f30222c08dad19b7d50b 100755 (executable)
--- a/configure
+++ b/configure
@@ -19,6 +19,8 @@ CXX=g++
 LD=gcc
 RUNWITH=lua
 EXCERTS=yes
+PRNG=
+PRNGLIBS=
 
 CFLAGS="-fPIC -Wall"
 LDFLAGS="-shared"
@@ -58,6 +60,11 @@ Configure Prosody prior to building.
                             icu: use ICU from IBM
 --with-ssl=LIB              The name of the SSL to link with.
                             Default is $OPENSSL_LIB
+--with-random=METHOD        CSPRNG backend to use. One of
+                            getrandom: Linux kernel
+                            arc4random: OpenBSD kernel
+                            openssl: OpenSSL RAND method
+                            Default is to use /dev/urandom
 --cflags=FLAGS              Flags to pass to the compiler
                             Default is $CFLAGS
 --ldflags=FLAGS             Flags to pass to the linker
@@ -174,6 +181,16 @@ do
    --with-ssl=*)
       OPENSSL_LIB="$value"
       ;;
+  --with-random=getrandom)
+      PRNG=GETRANDOM
+      ;;
+  --with-random=openssl)
+      PRNG=OPENSSL
+      PRNGLIBS=-lcrypto
+      ;;
+  --with-random=arc4random)
+      PRNG=ARC4RANDOM
+      ;;
    --cflags=*)
       CFLAGS="$value"
       ;;
@@ -372,6 +389,9 @@ CXX=$CXX
 LD=$LD
 RUNWITH=$RUNWITH
 EXCERTS=$EXCERTS
+RANDOM=$PRNG
+RANDOM_LIBS=$PRNGLIBS
+
 
 EOF
 

diff --git a/util-src/Makefile b/util-src/Makefile
index 85b190b9ae4dd9f7a719143a55e99d314391b549..9c6c377c14a56fd4816729ebf4f45b77a9e5e17f 100644 (file)
--- a/util-src/Makefile
+++ b/util-src/Makefile
@@ -8,6 +8,10 @@ TARGET?=../util/
 
 ALL=encodings.so hashes.so net.so pposix.so signal.so table.so ringbuffer.so
 
+ifdef RANDOM
+ALL+=crand.so
+endif
+
 .PHONY: all install clean
 .SUFFIXES: .c .o .so
 
@@ -17,11 +21,14 @@ install: $(ALL)
        $(INSTALL_DATA) $^ $(TARGET)
 
 clean:
-       rm -f $(ALL)
+       rm -f $(ALL) $(patsubst %.so,%.o,$(ALL))
 
 encodings.so: LDLIBS+=$(IDNA_LIBS)
 
 hashes.so: LDLIBS+=$(OPENSSL_LIBS)
 
+crand.o: CFLAGS+=-DWITH_$(RANDOM)
+crand.so: LDLIBS+=$(RANDOM_LIBS)
+
 %.so: %.o
        $(LD) $(LDFLAGS) -o $@ $^ $(LDLIBS)

diff --git a/util-src/crand.c b/util-src/crand.c
new file mode 100644 (file)
index 0000000..9a45f10
--- /dev/null
+++ b/util-src/crand.c
@@ -0,0 +1,156 @@
+/* Prosody IM
+-- Copyright (C) 2008-2016 Matthew Wild
+-- Copyright (C) 2008-2016 Waqas Hussain
+-- Copyright (C) 2016 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
+*/
+
+#include "lualib.h"
+#include "lauxlib.h"
+
+#include <string.h>
+#include <errno.h>
+
+/*
+ * TODO: Decide on fixed size or dynamically allocated buffer
+ */
+#if 1
+#include <malloc.h>
+#else
+#define BUFLEN 256
+#endif
+
+#if defined(WITH_GETRANDOM)
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <linux/random.h>
+
+#ifndef SYS_getrandom
+#error getrandom() requires Linux 3.17 or later
+#endif
+
+/* Was this not supposed to be a function? */
+int getrandom(char *buf, size_t len, int flags) {
+       return syscall(SYS_getrandom, buf, len, flags);
+}
+
+#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) {
+#ifdef BUFLEN
+       unsigned char buf[BUFLEN];
+#else
+       unsigned char *buf;
+#endif
+       int ret = 0;
+       size_t len = (size_t)luaL_checkint(L, 1);
+#ifdef BUFLEN
+       len = len > BUFLEN ? BUFLEN : len;
+#else
+       buf = malloc(len);
+
+       if(buf == NULL) {
+               lua_pushnil(L);
+               lua_pushstring(L, "out of memory");
+               /* or it migth be better to
+                * return lua_error(L);
+                */
+               return 2;
+       }
+#endif
+
+#if defined(WITH_GETRANDOM)
+       ret = getrandom(buf, len, 0);
+
+       if(ret < 0) {
+#ifndef BUFLEN
+               free(buf);
+#endif
+               lua_pushnil(L);
+               lua_pushstring(L, strerror(errno));
+               lua_pushinteger(L, errno);
+               return 3;
+       }
+
+#elif defined(WITH_ARC4RANDOM)
+       arc4random_buf(buf, len);
+       ret = len;
+#elif defined(WITH_OPENSSL)
+       ret = RAND_bytes(buf, len);
+
+       if(ret == 1) {
+               ret = len;
+       } else {
+#ifndef BUFLEN
+               free(buf);
+#endif
+               lua_pushnil(L);
+               lua_pushstring(L, "failed");
+               /* lua_pushinteger(L, ERR_get_error()); */
+               return 2;
+       }
+
+#endif
+
+       lua_pushlstring(L, buf, ret);
+#ifndef BUFLEN
+       free(buf);
+#endif
+       return 1;
+}
+
+#ifdef ENABLE_SEEDING
+int Lseed(lua_State *L) {
+       size_t len;
+       const char *seed = lua_tolstring(L, 1, &len);
+
+#if defined(WITH_OPENSSL)
+       RAND_add(seed, len, len);
+       return 0;
+#else
+       lua_pushnil(L);
+       lua_pushliteral(L, "not-supported");
+       return 2;
+#endif
+}
+#endif
+
+int luaopen_util_crand(lua_State *L) {
+       lua_newtable(L);
+       lua_pushcfunction(L, Lrandom);
+       lua_setfield(L, -2, "bytes");
+#ifdef ENABLE_SEEDING
+       lua_pushcfunction(L, Lseed);
+       lua_setfield(L, -2, "seed");
+#endif
+
+#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");
+
+#if defined(WITH_OPENSSL) && defined(_WIN32)
+       /* Do we need to seed this on Windows? */
+#endif
+
+       return 1;
+}
+

diff --git a/util/random.lua b/util/random.lua
index e4b4a700a89c15b2bb72397094ad1b7f0b16fd51..574e2e1cdf384cf7d893530fdcd97c80843aaba7 100644 (file)
--- a/util/random.lua
+++ b/util/random.lua
@@ -6,6 +6,9 @@
 -- COPYING file in the source package for more information.
 --
 
+local ok, crand = pcall(require, "util.crand");
+if ok then return crand; end
+
 local urandom, urandom_err = io.open("/dev/urandom", "r");
 
 local function seed()