Improve security of random number generation (support EGD, use MD5
in our poor man's version) - Jacco de Leeuw <jacco2@dds.nl> git-svn-id: svn://svn.code.sf.net/p/rdesktop/code/trunk/rdesktop@219 423420c4-83ab-492f-b58f-81f9feb106b5
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43
configure
vendored
43
configure
vendored
@ -34,10 +34,17 @@ case $arg in
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--sharedir=*)
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echo "datadir = $optarg" >>Makeconf
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;;
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--with-x*)
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extraxdir=$optarg
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;;
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--with-openssl*)
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extrassldir=$optarg
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;;
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--without-openssl*)
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;;
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--with-egd-socket=*)
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extraegdpath=$optarg
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;;
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--with-debug)
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cflags="$cflags -g -DWITH_DEBUG"
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;;
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@ -55,6 +62,9 @@ case $arg in
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echo " --sharedir=SHAREDIR location for architecture-independent shared files [PREFIX/share/rdesktop]"
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echo
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echo "Build configuration:"
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echo " --with-x=DIR look for X Window System at DIR/include, DIR/lib"
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echo " --with-openssl=DIR look for OpenSSL at DIR/include, DIR/lib"
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echo " --with-egd-socket=PATH look for Entropy Gathering Daemon socket at PATH"
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echo " --with-debug enable protocol debugging output"
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echo " --with-debug-kbd enable debugging of keyboard handling"
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echo
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@ -79,7 +89,7 @@ esac
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# Find X installation
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xdirs="/usr/X11R6 /usr/X11 /usr/openwin /usr /usr/local/X11R6 /usr/local/X11 /usr/local"
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xdirs="$extraxdir /usr/X11R6 /usr/X11 /usr/openwin /usr /usr/local/X11R6 /usr/local/X11 /usr/local"
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for dir in $xdirs; do
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if [ -f $dir/include/X11/Xlib.h ]; then
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@ -90,7 +100,7 @@ done
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if [ -z "$xdir" ]; then
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echo "ERROR: could not find X Window System headers"
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echo "(searched for include/X11/Xlib.h in $xdirs)"
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echo "(searched for include/X11/Xlib.h in: $xdirs)"
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# additional helpful information for Linux users
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if [ -f /etc/redhat_release ]; then
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@ -119,7 +129,7 @@ ldflags="$ldflags -lX11"
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# Find OpenSSL installation if available
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ssldirs="/usr/openssl /usr/ssl /usr /usr/local/openssl /usr/local/ssl /usr/local"
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ssldirs="$extrassldir /usr/openssl /usr/ssl /usr /usr/local/openssl /usr/local/ssl /usr/local"
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for dir in $ssldirs; do
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if [ -f $dir/include/openssl/rc4.h ]; then
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@ -130,7 +140,7 @@ done
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if [ -z "$ssldir" ]; then
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echo "WARNING: could not find OpenSSL headers"
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echo "(searched for include/openssl/rc4.h in $ssldirs)"
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echo "(searched for include/openssl/rc4.h in: $ssldirs)"
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echo "Using in-tree crypto; installing OpenSSL is recommended."
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echo
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else
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@ -154,6 +164,31 @@ else
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fi
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# Find EGD socket if we don't have /dev/urandom or /dev/random
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if [ ! -c /dev/random -a ! -c /dev/urandom ]; then
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egdpaths="$extraegdpath /var/run/egd-pool /dev/egd-pool /etc/egd-pool /etc/entropy"
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for path in $egdpaths; do
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# -e isn't portable, so we use -r
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if [ -r $path ]; then
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egdpath=$path
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break
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fi
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done
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if [ -z "$egdpath" ]; then
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echo "WARNING: could not find /dev/urandom, /dev/random or Entropy Gathering Daemon (EGD) socket"
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echo "(searched: $egdpaths)"
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echo "Session keys may be less secure; installing a system randomness source is recommended."
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echo
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else
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echo "Entropy Gathering Daemon (EGD):"
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echo " socket $egdpath"
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echo
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cflags="$cflags -DEGD_SOCKET=\\\"$egdpath\\\""
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fi
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fi
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echo "CFLAGS += $cflags" >>Makeconf
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echo "LDFLAGS += $ldflags" >>Makeconf
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73
rdesktop.c
73
rdesktop.c
@ -29,6 +29,17 @@
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#include <sys/times.h> /* times */
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#include "rdesktop.h"
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#ifdef EGD_SOCKET
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#include <sys/socket.h> /* socket connect */
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#include <sys/un.h> /* sockaddr_un */
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#endif
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#ifdef WITH_OPENSSL
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#include <openssl/md5.h>
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#else
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#include "crypto/md5.h"
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#endif
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char title[32] = "";
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char username[16];
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char hostname[16];
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@ -284,25 +295,72 @@ main(int argc, char *argv[])
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return 0;
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}
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#ifdef EGD_SOCKET
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/* Read 32 random bytes from PRNGD or EGD socket (based on OpenSSL RAND_egd) */
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static BOOL
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generate_random_egd(uint8 * buf)
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{
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struct sockaddr_un addr;
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BOOL ret = False;
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int fd;
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fd = socket(AF_UNIX, SOCK_STREAM, 0);
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if (fd == -1)
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return False;
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addr.sun_family = AF_UNIX;
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memcpy(addr.sun_path, EGD_SOCKET, sizeof(EGD_SOCKET));
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if (connect(fd, (struct sockaddr *)&addr, sizeof(addr)) == -1)
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goto err;
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/* PRNGD and EGD use a simple communications protocol */
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buf[0] = 1; /* Non-blocking (similar to /dev/urandom) */
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buf[1] = 32; /* Number of requested random bytes */
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if (write(fd, buf, 2) != 2)
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goto err;
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if ((read(fd, buf, 1) != 1) || (buf[0] == 0)) /* Available? */
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goto err;
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if (read(fd, buf, 32) != 32)
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goto err;
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ret = True;
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err:
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close(fd);
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return ret;
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}
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#endif
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/* Generate a 32-byte random for the secure transport code. */
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void
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generate_random(uint8 * random)
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{
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struct stat st;
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struct tms tmsbuf;
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uint32 *r = (uint32 *) random;
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int fd;
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MD5_CTX md5;
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uint32 *r;
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int fd, n;
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/* If we have a kernel random device, use it. */
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/* If we have a kernel random device, try that first */
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if (((fd = open("/dev/urandom", O_RDONLY)) != -1)
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|| ((fd = open("/dev/random", O_RDONLY)) != -1))
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{
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read(fd, random, 32);
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n = read(fd, random, 32);
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close(fd);
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if (n == 32)
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return;
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}
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#ifdef EGD_SOCKET
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/* As a second preference use an EGD */
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if (generate_random_egd(random))
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return;
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#endif
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/* Otherwise use whatever entropy we can gather - ideas welcome. */
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r = (uint32 *)random;
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r[0] = (getpid()) | (getppid() << 16);
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r[1] = (getuid()) | (getgid() << 16);
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r[2] = times(&tmsbuf); /* system uptime (clocks) */
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@ -311,6 +369,13 @@ generate_random(uint8 * random)
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r[5] = st.st_atime;
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r[6] = st.st_mtime;
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r[7] = st.st_ctime;
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/* Hash both halves with MD5 to obscure possible patterns */
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MD5_Init(&md5);
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MD5_Update(&md5, random, 16);
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MD5_Final(random, &md5);
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MD5_Update(&md5, random+16, 16);
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MD5_Final(random+16, &md5);
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}
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/* malloc; exit if out of memory */
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