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Diffstat (limited to 'contrib/pwdauth.c')
| -rw-r--r-- | contrib/pwdauth.c | 308 |
1 files changed, 0 insertions, 308 deletions
diff --git a/contrib/pwdauth.c b/contrib/pwdauth.c deleted file mode 100644 index ca15495..0000000 --- a/contrib/pwdauth.c +++ /dev/null @@ -1,308 +0,0 @@ -/* - * pwdauth.c - program to verify a given username/password pair. - * - * Run it with username in argv[1] (may be omitted - default is the - * current user), and send it the password over a pipe on stdin. - * Exit status: 0 - correct password, 1 - wrong password, >1 - other - * errors. For use with shadow passwords, this program should be - * installed setuid root. - * - * This can be used, for example, by xlock - you don't have to install - * this large and complex (== possibly insecure) program setuid root, - * just modify it to run this simple program to do the authentication. - * - * Recent versions (xlockmore-3.9) are cleaner, and drop privileges as - * soon as possible after getting the user's encrypted password. - * Using this program probably doesn't make it more secure, and has one - * disadvantage: since we don't get the encrypted user's password at - * startup (but at the time the user is authenticated), it is not clear - * how we should handle errors (like getpwnam() returning NULL). - * - fail the authentication? Problem: no way to unlock (other than kill - * the process from somewhere else) if the NIS server stops responding. - * - succeed and unlock? Problem: it's too easy to unlock by unplugging - * the box from the network and waiting until NIS times out... - * - * This program is Copyright (C) 1996 Marek Michalkiewicz - * <marekm@i17linuxb.ists.pwr.wroc.pl>. - * - * It may be used and distributed freely for any purposes. There is no - * warranty - use at your own risk. I am not liable for any damages etc. - * If you improve it, please send me your changes. - */ - -static char rcsid[] = "$Id$"; - -/* - * Define USE_SYSLOG to use syslog() to log successful and failed - * authentication. This should be safe even if your system has - * the infamous syslog buffer overrun security problem... - */ -#define USE_SYSLOG - -/* - * Define HAVE_GETSPNAM to get shadow passwords using getspnam(). - * Some systems don't have getspnam(), but getpwnam() returns - * encrypted passwords only if running as root. - * - * According to the xlock source (not tested, except Linux) - - * define: Linux, Solaris 2.x, SVR4, ... - * undef: HP-UX with Secured Passwords, FreeBSD, NetBSD, QNX. - * Known not supported (yet): Ultrix, OSF/1, SCO. - */ -#define HAVE_GETSPNAM - -/* - * Define HAVE_PW_ENCRYPT to use pw_encrypt() instead of crypt(). - * pw_encrypt() is like the standard crypt(), except that it may - * support better password hashing algorithms. - * - * Define if linking with libshadow.a from the shadow password - * suite (Linux, SunOS 4.x?). - */ -#undef HAVE_PW_ENCRYPT - -/* - * Define HAVE_AUTH_METHODS to support the shadow suite specific - * extension: the encrypted password field contains a list of - * administrator defined authentication methods, separated by - * semicolons. This program only supports the standard password - * authentication method (a string that doesn't start with '@'). - */ -#undef HAVE_AUTH_METHODS - -/* - * FAIL_DELAY - number of seconds to sleep before exiting if the - * password was wrong, to slow down password guessing attempts. - */ -#define FAIL_DELAY 2 - -/* No user-serviceable parts below :-). */ - -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <sys/types.h> -#include <sys/wait.h> -#include <unistd.h> -#include <pwd.h> - -#ifdef USE_SYSLOG -#include <syslog.h> -#ifndef LOG_AUTHPRIV -#define LOG_AUTHPRIV LOG_AUTH -#endif -#endif - -#ifdef HAVE_GETSPNAM -#include <shadow.h> -#endif - -#ifdef HAVE_PW_ENCRYPT -extern char *pw_encrypt(); -#define crypt pw_encrypt -#endif - -/* - * Read the password (one line) from fp. We don't turn off echo - * because we expect input from a pipe. - */ -static char * -get_line(fp) - FILE *fp; -{ - static char buf[128]; - char *cp; - int ch; - - cp = buf; - while ((ch = getc(fp)) != EOF && ch != '\0' && ch != '\n') { - if (cp >= buf + sizeof buf - 1) - break; - *cp++ = ch; - } - *cp = '\0'; - return buf; -} - -/* - * Get the password file entry for the current user. If the name - * returned by getlogin() is correct (matches the current real uid), - * return the entry for that user. Otherwise, return the entry (if - * any) matching the current real uid. Return NULL on failure. - */ -static struct passwd * -get_my_pwent() -{ - uid_t uid = getuid(); - char *name = getlogin(); - - if (name && *name) { - struct passwd *pw = getpwnam(name); - - if (pw && pw->pw_uid == uid) - return pw; - } - return getpwuid(uid); -} - -/* - * Verify the password. The system-dependent shadow support is here. - */ -static int -password_auth_ok(pw, pass) - const struct passwd *pw; - const char *pass; -{ - int result; - char *cp; -#ifdef HAVE_AUTH_METHODS - char *buf; -#endif -#ifdef HAVE_GETSPNAM - struct spwd *sp; -#endif - - if (pw) { -#ifdef HAVE_GETSPNAM - sp = getspnam(pw->pw_name); - if (sp) - cp = sp->sp_pwdp; - else -#endif - cp = pw->pw_passwd; - } else - cp = "xx"; - -#ifdef HAVE_AUTH_METHODS - buf = strdup(cp); /* will be modified by strtok() */ - if (!buf) { - fprintf(stderr, "Out of memory.\n"); - exit(13); - } - cp = strtok(buf, ";"); - while (cp && *cp == '@') - cp = strtok(NULL, ";"); - - /* fail if no password authentication for this user */ - if (!cp) - cp = "xx"; -#endif - - if (*pass || *cp) - result = (strcmp(crypt(pass, cp), cp) == 0); - else - result = 1; /* user with no password */ - -#ifdef HAVE_AUTH_METHODS - free(buf); -#endif - return result; -} - -/* - * Main program. - */ -int -main(argc, argv) - int argc; - char **argv; -{ - struct passwd *pw; - char *pass, *name; - char myname[32]; - -#ifdef USE_SYSLOG - openlog("pwdauth", LOG_PID | LOG_CONS, LOG_AUTHPRIV); -#endif - pw = get_my_pwent(); - if (!pw) { -#ifdef USE_SYSLOG - syslog(LOG_ERR, "can't get login name for uid %d.\n", - (int) getuid()); -#endif - fprintf(stderr, "Who are you?\n"); - exit(2); - } - strncpy(myname, pw->pw_name, sizeof myname - 1); - myname[sizeof myname - 1] = '\0'; - name = myname; - - if (argc > 1) { - name = argv[1]; - pw = getpwnam(name); - } - - pass = get_line(stdin); - if (password_auth_ok(pw, pass)) { -#ifdef USE_SYSLOG - syslog(pw->pw_uid ? LOG_INFO : LOG_NOTICE, - "user `%s' entered correct password for `%.32s'.\n", - myname, name); -#endif - exit(0); - } -#ifdef USE_SYSLOG - /* be careful not to overrun the syslog buffer */ - syslog((!pw || pw->pw_uid) ? LOG_NOTICE : LOG_WARNING, - "user `%s' entered incorrect password for `%.32s'.\n", - myname, name); -#endif -#ifdef FAIL_DELAY - sleep(FAIL_DELAY); -#endif - fprintf(stderr, "Wrong password.\n"); - exit(1); -} - -#if 0 -/* - * You can use code similar to the following to run this program. - * Return values: >=0 - program exit status (use the <sys/wait.h> - * macros to get the exit code, it is shifted left by 8 bits), - * -1 - check errno. - */ -int -verify_password(const char *username, const char *password) -{ - int pipe_fd[2]; - int pid, wpid, status; - - if (pipe(pipe_fd)) - return -1; - - if ((pid = fork()) == 0) { - char *arg[3]; - char *env[1]; - - /* child */ - close(pipe_fd[1]); - if (pipe_fd[0] != 0) { - if (dup2(pipe_fd[0], 0) != 0) - _exit(127); - close(pipe_fd[0]); - } - arg[0] = "/usr/bin/pwdauth"; - arg[1] = username; - arg[2] = NULL; - env[0] = NULL; - execve(arg[0], arg, env); - _exit(127); - } else if (pid == -1) { - /* error */ - close(pipe_fd[0]); - close(pipe_fd[1]); - return -1; - } - /* parent */ - close(pipe_fd[0]); - write(pipe_fd[1], password, strlen(password)); - write(pipe_fd[1], "\n", 1); - close(pipe_fd[1]); - - while ((wpid = wait(&status)) != pid) { - if (wpid == -1) - return -1; - } - return status; -} -#endif |