Imported from util-linux-2.5 tarball.

1 files changed, 93 insertions, 17 deletions

diff --git a/misc-utils/mcookie.c b/misc-utils/mcookie.c
index d0730edde..a4c896075 100644
--- a/misc-utils/mcookie.c
+++ b/misc-utils/mcookie.c
@@ -1,43 +1,119 @@
 /* mcookie.c -- Generates random numbers for xauth
  * Created: Fri Feb  3 10:42:48 1995 by faith@cs.unc.edu
- * Revised: Sun Feb 12 20:29:58 1995 by faith@cs.unc.edu
+ * Revised: Mon Sep 25 23:44:43 1995 by r.faith@ieee.org
  * Public Domain 1995 Rickard E. Faith (faith@cs.unc.edu)
  * This program comes with ABSOLUTELY NO WARRANTY.
  * 
- * mcookie.c,v 1.1.1.1 1995/02/22 19:09:16 faith Exp
+ * $Id: mcookie.c,v 1.2 1995/10/07 01:32:00 faith Exp $
+ *
+ * This program gathers some random bits of data and used the MD5
+ * message-digest algorithm to generate a 128-bit hexadecimal number for
+ * use with xauth(1).
+ *
+ * NOTE: Unless /dev/random is available, this program does not actually
+ * gather 128 bits of random information, so the magic cookie generated
+ * will be considerably easier to guess than one might expect.
  */
 
-#define SECURE 1
+#ifdef __linux__
+#define HAVE_GETTIMEOFDAY 1
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>
-#if SECURE
+#include <fcntl.h>
+#include "md5.h"
+#if HAVE_GETTIMEOFDAY
 #include <sys/time.h>
 #include <unistd.h>
 #endif
 
-int main( void )
+#define MAXBUFFERSIZE 512
+
+struct rngs {
+   const char *path;
+   int        length;
+} rngs[] = {
+   { "/dev/random",              16 },
+   { "/dev/urandom",            128 },
+   { "/proc/stat",    MAXBUFFERSIZE },
+   { "/proc/loadavg", MAXBUFFERSIZE },
+   { "/dev/audio",    MAXBUFFERSIZE },
+};
+#define RNGS (sizeof(rngs)/sizeof(struct rngs))
+
+int Verbose = 0;
+
+int main( int argc, char **argv )
 {
-   int      i;
-#if SECURE
-   struct timeval  tv;
-   struct timezone tz;
+   int               i;
+   struct MD5Context ctx;
+   unsigned char     digest[16];
+   unsigned char     buf[MAXBUFFERSIZE];
+   int               fd;
+   int               c;
+   pid_t             pid;
+   char              *file = NULL;
+   int               r;
+#if HAVE_GETTIMEOFDAY
+   struct timeval    tv;
+   struct timezone   tz;
+#else
+   long int          t;
+#endif
 
+   while ((c = getopt( argc, argv, "vf:" )) != EOF)
+      switch (c) {
+      case 'v': ++Verbose;     break;
+      case 'f': file = optarg; break;
+      }
+
+   MD5Init( &ctx );
+   
+#if HAVE_GETTIMEOFDAY
    gettimeofday( &tv, &tz );
-   srand( tv.tv_sec + tv.tv_usec );
+   MD5Update( &ctx, (unsigned char *)&tv, sizeof( tv ) );
 #else
-   long int t;
-   
    time( &t );
-   srand( t );
+   MD5Update( &ctx, (unsigned char *)&t, sizeof( t ) );
 #endif
+   pid = getppid();
+   MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
+   pid = getpid();
+   MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
 
-   for (i = 0; i < 32; i++) {
-      int r = (rand() & 0x0f0) >> 4;
+   if (file) {
+      int count = 0;
+      
+      if (file[0] == '-' && !file[1]) fd = fileno(stdin);
+      else if ((fd = open( file, O_RDONLY )) <0) {
+	 fprintf( stderr, "Could not open %s\n" );
+      }
 
-      if (r < 10) putchar( '0' + r );
-      else        putchar( 'a' + r - 10 );
+      while ((r = read( fd, buf, sizeof( buf ) )) > 0) {
+	 MD5Update( &ctx, buf, r );
+	 count += r;
+      }
+      if (Verbose)
+	 fprintf( stderr, "Got %d bytes from %s\n", count, file );
+      
+      if (file[0] != '-' || file[1]) close( fd );
    }
+
+   for (i = 0; i < RNGS; i++) {
+      if ((fd = open( rngs[i].path, O_RDONLY )) >= 0) {
+	 r = read( fd, buf, sizeof( buf ) );
+	 MD5Update( &ctx, buf, r );
+	 close( fd );
+	 if (Verbose)
+	    fprintf( stderr, "Got %d bytes from %s\n", r, rngs[i].path );
+	 if (r >= rngs[i].length) break;
+      } else if (Verbose)
+	 fprintf( stderr, "Could not open %s\n", rngs[i].path );
+   }
+
+   MD5Final( digest, &ctx );
+   for (i = 0; i < 16; i++) printf( "%02x", digest[i] );
    putchar ( '\n' );
    
    return 0;