-/* mcookie.c -- Generates random numbers for xauth
+/*
+ * No copyright is claimed. This code is in the public domain; do with
+ * it what you wish.
+ *
+ * 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
- * Public Domain 1995 Rickard E. Faith (faith@cs.unc.edu)
+ * Revised: Fri Mar 19 07:48:01 1999 by faith@acm.org
+ * Public Domain 1995, 1999 Rickard E. Faith (faith@acm.org)
* This program comes with ABSOLUTELY NO WARRANTY.
- *
- * mcookie.c,v 1.1.1.1 1995/02/22 19:09:16 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.
+ *
+ * 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
+ * - added Native Language Support
+ * 1999-03-21 aeb: Added some fragments of code from Colin Plumb.
+ *
*/
-#define SECURE 1
+#include "c.h"
+#include "md5.h"
+#include "nls.h"
+#include "closestream.h"
+#include "randutils.h"
+#include "strutils.h"
+#include "xalloc.h"
+#include "all-io.h"
+#include <fcntl.h>
+#include <getopt.h>
+#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
-#if SECURE
#include <sys/time.h>
#include <unistd.h>
-#endif
-int main( void )
+enum {
+ BUFFERSIZE = 4096,
+ RAND_BYTES = 128
+};
+
+struct mcookie_control {
+ struct UL_MD5Context ctx;
+ char **files;
+ size_t nfiles;
+ uint64_t maxsz;
+
+ unsigned int verbose:1;
+};
+
+/* The basic function to hash a file */
+static uint64_t hash_file(struct mcookie_control *ctl, int fd)
+{
+ unsigned char buf[BUFFERSIZE];
+ uint64_t wanted, count;
+
+ wanted = ctl->maxsz ? ctl->maxsz : sizeof(buf);
+
+ for (count = 0; count < wanted; ) {
+ size_t rdsz = sizeof(buf);
+ ssize_t r;
+
+ if (wanted - count < rdsz)
+ rdsz = wanted - count;
+
+ r = read_all(fd, (char *) buf, rdsz);
+ if (r <= 0)
+ break;
+ ul_MD5Update(&ctl->ctx, buf, r);
+ count += r;
+ }
+ /* Separate files with a null byte */
+ buf[0] = '\0';
+ ul_MD5Update(&ctl->ctx, buf, 1);
+ return count;
+}
+
+static void __attribute__((__noreturn__)) usage(void)
{
- int i;
-#if SECURE
- struct timeval tv;
- struct timezone tz;
-
- gettimeofday( &tv, &tz );
- srand( tv.tv_sec + tv.tv_usec );
-#else
- long int t;
-
- time( &t );
- srand( t );
-#endif
-
- for (i = 0; i < 32; i++) {
- int r = (rand() & 0x0f0) >> 4;
-
- if (r < 10) putchar( '0' + r );
- else putchar( 'a' + r - 10 );
- }
- putchar ( '\n' );
-
- return 0;
+ FILE *out = stdout;
+ fputs(USAGE_HEADER, out);
+ fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
+
+ fputs(USAGE_SEPARATOR, out);
+ fputs(_("Generate magic cookies for xauth.\n"), out);
+
+ fputs(USAGE_OPTIONS, out);
+ fputs(_(" -f, --file <file> use file as a cookie seed\n"), out);
+ fputs(_(" -m, --max-size <num> limit how much is read from seed files\n"), out);
+ fputs(_(" -v, --verbose explain what is being done\n"), out);
+
+ fputs(USAGE_SEPARATOR, out);
+ fprintf(out, USAGE_HELP_OPTIONS(23));
+
+ fputs(USAGE_ARGUMENTS, out);
+ fprintf(out, USAGE_ARG_SIZE(_("<num>")));
+
+ fprintf(out, USAGE_MAN_TAIL("mcookie(1)"));
+
+ exit(EXIT_SUCCESS);
+}
+
+static void randomness_from_files(struct mcookie_control *ctl)
+{
+ size_t i;
+
+ for (i = 0; i < ctl->nfiles; i++) {
+ const char *fname = ctl->files[i];
+ size_t count;
+ int fd;
+
+ if (*fname == '-' && !*(fname + 1))
+ fd = STDIN_FILENO;
+ else
+ fd = open(fname, O_RDONLY);
+
+ if (fd < 0) {
+ warn(_("cannot open %s"), fname);
+ } else {
+ count = hash_file(ctl, fd);
+ if (ctl->verbose)
+ fprintf(stderr,
+ P_("Got %zu byte from %s\n",
+ "Got %zu bytes from %s\n", count),
+ count, fname);
+
+ if (fd != STDIN_FILENO && close(fd))
+ err(EXIT_FAILURE, _("closing %s failed"), fname);
+ }
+ }
+}
+
+int main(int argc, char **argv)
+{
+ struct mcookie_control ctl = { .verbose = 0 };
+ size_t i;
+ unsigned char digest[UL_MD5LENGTH];
+ unsigned char buf[RAND_BYTES];
+ int c;
+
+ static const struct option longopts[] = {
+ {"file", required_argument, NULL, 'f'},
+ {"max-size", required_argument, NULL, 'm'},
+ {"verbose", no_argument, NULL, 'v'},
+ {"version", no_argument, NULL, 'V'},
+ {"help", no_argument, NULL, 'h'},
+ {NULL, 0, NULL, 0}
+ };
+
+ setlocale(LC_ALL, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+ close_stdout_atexit();
+
+ while ((c = getopt_long(argc, argv, "f:m:vVh", longopts, NULL)) != -1) {
+ switch (c) {
+ case 'v':
+ ctl.verbose = 1;
+ break;
+ case 'f':
+ if (!ctl.files)
+ ctl.files = xmalloc(sizeof(char *) * argc);
+ ctl.files[ctl.nfiles++] = optarg;
+ break;
+ case 'm':
+ ctl.maxsz = strtosize_or_err(optarg,
+ _("failed to parse length"));
+ break;
+
+ case 'V':
+ print_version(EXIT_SUCCESS);
+ case 'h':
+ usage();
+ default:
+ errtryhelp(EXIT_FAILURE);
+ }
+ }
+
+ if (ctl.maxsz && ctl.nfiles == 0)
+ warnx(_("--max-size ignored when used without --file"));
+
+ ul_MD5Init(&ctl.ctx);
+ randomness_from_files(&ctl);
+ free(ctl.files);
+
+ ul_random_get_bytes(&buf, RAND_BYTES);
+ ul_MD5Update(&ctl.ctx, buf, RAND_BYTES);
+ if (ctl.verbose)
+ fprintf(stderr, P_("Got %d byte from %s\n",
+ "Got %d bytes from %s\n", RAND_BYTES),
+ RAND_BYTES, random_tell_source());
+
+ ul_MD5Final(digest, &ctl.ctx);
+ for (i = 0; i < UL_MD5LENGTH; i++)
+ printf("%02x", digest[i]);
+ putchar('\n');
+
+ return EXIT_SUCCESS;
}
projects / thirdparty / util-linux.git / blobdiff