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Diffstat (limited to 'misc-utils/mcookie.c')
| -rw-r--r-- | misc-utils/mcookie.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/misc-utils/mcookie.c b/misc-utils/mcookie.c new file mode 100644 index 0000000..b7b1762 --- /dev/null +++ b/misc-utils/mcookie.c @@ -0,0 +1,190 @@ +/* mcookie.c -- Generates random numbers for xauth + * Created: Fri Feb 3 10:42:48 1995 by 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. + * + * 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 Mi¶kiewicz <misiek@pld.ORG.PL> + * - added Native Language Support + * 1999-03-21 aeb: Added some fragments of code from Colin Plumb. + * + */ + +#include "c.h" +#include "md5.h" +#include "nls.h" +#include "closestream.h" + +#include <fcntl.h> +#include <getopt.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/time.h> +#include <unistd.h> + +#define BUFFERSIZE 4096 + +struct rngs { + const char *path; + int minlength, maxlength; +} rngs[] = { + {"/dev/random", 16, 16}, /* 16 bytes = 128 bits suffice */ + {"/proc/interrupts", 0, 0}, + {"/proc/slabinfo", 0, 0}, + {"/proc/stat", 0, 0}, + {"/dev/urandom", 32, 64}, +}; + +#define RNGS (sizeof(rngs)/sizeof(struct rngs)) + +/* The basic function to hash a file */ +static off_t hash_file(struct MD5Context *ctx, int fd) +{ + off_t count = 0; + ssize_t r; + unsigned char buf[BUFFERSIZE]; + + while ((r = read(fd, buf, sizeof(buf))) > 0) { + MD5Update(ctx, buf, r); + count += r; + } + /* Separate files with a null byte */ + buf[0] = '\0'; + MD5Update(ctx, buf, 1); + return count; +} + +static void __attribute__ ((__noreturn__)) usage(FILE * out) +{ + fputs(_("\nUsage:\n"), out); + fprintf(out, + _(" %s [options]\n"), program_invocation_short_name); + + fputs(_("\nOptions:\n"), out); + fputs(_(" -f, --file <file> use file as a cookie seed\n" + " -v, --verbose explain what is being done\n" + " -V, --version output version information and exit\n" + " -h, --help display this help and exit\n\n"), out); + + exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS); +} + +int main(int argc, char **argv) +{ + size_t i; + struct MD5Context ctx; + unsigned char digest[MD5LENGTH]; + unsigned char buf[BUFFERSIZE]; + int fd; + int c; + pid_t pid; + char *file = NULL; + int verbose = 0; + int r; + struct timeval tv; + struct timezone tz; + + static const struct option longopts[] = { + {"file", required_argument, NULL, 'f'}, + {"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); + atexit(close_stdout); + + while ((c = + getopt_long(argc, argv, "f:vVh", longopts, NULL)) != -1) + switch (c) { + case 'v': + verbose = 1; + break; + case 'f': + file = optarg; + break; + case 'V': + printf(_("%s from %s\n"), + program_invocation_short_name, + PACKAGE_STRING); + return EXIT_SUCCESS; + case 'h': + usage(stdout); + default: + usage(stderr); + } + + MD5Init(&ctx); + gettimeofday(&tv, &tz); + MD5Update(&ctx, (unsigned char *) &tv, sizeof(tv)); + + pid = getppid(); + MD5Update(&ctx, (unsigned char *) &pid, sizeof(pid)); + pid = getpid(); + MD5Update(&ctx, (unsigned char *) &pid, sizeof(pid)); + + if (file) { + int count = 0; + + if (file[0] == '-' && !file[1]) + fd = STDIN_FILENO; + else + fd = open(file, O_RDONLY); + + if (fd < 0) { + warn(_("cannot open %s"), file); + } else { + count = hash_file(&ctx, fd); + if (verbose) + fprintf(stderr, + _("Got %d bytes from %s\n"), count, + file); + + if (fd != STDIN_FILENO) + if (close(fd)) + err(EXIT_FAILURE, + _("closing %s failed"), file); + } + } + + for (i = 0; i < RNGS; i++) { + if ((fd = open(rngs[i].path, O_RDONLY | O_NONBLOCK)) >= 0) { + int count = sizeof(buf); + + if (rngs[i].maxlength && count > rngs[i].maxlength) + count = rngs[i].maxlength; + r = read(fd, buf, count); + if (r > 0) + MD5Update(&ctx, buf, r); + else + r = 0; + close(fd); + if (verbose) + fprintf(stderr, + _("Got %d bytes from %s\n"), r, + rngs[i].path); + if (rngs[i].minlength && r >= rngs[i].minlength) + break; + } else if (verbose) + warn(_("cannot open %s"), rngs[i].path); + } + + MD5Final(digest, &ctx); + for (i = 0; i < MD5LENGTH; i++) + printf("%02x", digest[i]); + putchar('\n'); + + return EXIT_SUCCESS; +} |