127 lines
2.4 KiB
C
127 lines
2.4 KiB
C
/* See LICENSE file for copyright and license details. */
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#define _XOPEN_SOURCE
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#include <errno.h>
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#include <grp.h>
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#include <pwd.h>
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#include <shadow.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "config.h"
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#include "util.h"
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static int dologin(struct passwd *, int);
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static void
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usage(void)
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{
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eprintf("usage: %s [-p] username\n", argv0);
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}
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int
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main(int argc, char *argv[])
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{
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struct passwd *pw;
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struct spwd *spw;
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char *pass, *cryptpass;
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uid_t uid;
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gid_t gid;
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int pflag = 0;
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ARGBEGIN {
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case 'p':
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pflag = 1;
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break;
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default:
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usage();
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} ARGEND;
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if (argc < 1)
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usage();
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if (isatty(STDIN_FILENO) == 0)
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eprintf("stdin is not a tty\n");
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errno = 0;
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pw = getpwnam(argv[0]);
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if (errno)
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eprintf("getpwnam: %s:", argv[0]);
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else if (!pw)
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eprintf("who are you?\n");
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switch (pw->pw_passwd[0]) {
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case '!':
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case '*':
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eprintf("denied\n");
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}
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uid = pw->pw_uid;
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gid = pw->pw_gid;
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/* Empty password? Login now */
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if (pw->pw_passwd[0] == '\0')
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goto login;
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/* Flush pending input */
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ioctl(STDIN_FILENO, TCFLSH, (void *)0);
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pass = getpass("Password: ");
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if (!pass)
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eprintf("getpass:");
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if (pw->pw_passwd[0] == 'x' && pw->pw_passwd[1] == '\0') {
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errno = 0;
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spw = getspnam(argv[0]);
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if (errno)
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eprintf("getspnam: %s:", argv[0]);
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else if (!spw)
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eprintf("who are you?\n");
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switch (spw->sp_pwdp[0]) {
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case '!':
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case '*':
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eprintf("denied\n");
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}
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cryptpass = crypt(pass, spw->sp_pwdp);
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if (!cryptpass)
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eprintf("crypt:");
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if (strcmp(cryptpass, spw->sp_pwdp) != 0)
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eprintf("login failed\n");
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} else {
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cryptpass = crypt(pass, pw->pw_passwd);
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if (!cryptpass)
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eprintf("crypt:");
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if (strcmp(cryptpass, pw->pw_passwd) != 0)
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eprintf("login failed\n");
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}
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login:
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if (initgroups(argv[0], gid) < 0)
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eprintf("initgroups:");
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if (setgid(gid) < 0)
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eprintf("setgid:");
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if (setuid(uid) < 0)
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eprintf("setuid:");
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return dologin(pw, pflag);
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}
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static int
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dologin(struct passwd *pw, int preserve)
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{
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if (preserve == 0)
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clearenv();
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setenv("HOME", pw->pw_dir, !preserve);
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setenv("SHELL", pw->pw_shell, !preserve);
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setenv("USER", pw->pw_name, !preserve);
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setenv("LOGNAME", pw->pw_name, !preserve);
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setenv("PATH", ENV_PATH, !preserve);
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if (chdir(pw->pw_dir) < 0)
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eprintf("chdir %s:", pw->pw_dir);
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execlp(pw->pw_shell, pw->pw_shell, "-l", NULL);
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weprintf("execlp %s:", pw->pw_shell);
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return (errno == ENOENT) ? 127 : 126;
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}
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