163 lines
3.1 KiB
C
163 lines
3.1 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <sys/types.h>
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#include <unistd.h>
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#include <errno.h>
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#include <pwd.h>
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#include <grp.h>
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#include <shadow.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include "config.h"
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#include "util.h"
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extern char **environ;
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static char *msetenv(const char *, const char *);
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static void dologin(struct passwd *);
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static void
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usage(void)
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{
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eprintf("usage: %s [-lp] [username]\n", argv0);
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}
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static int lflag = 0;
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static int pflag = 0;
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int
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main(int argc, char **argv)
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{
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char *usr = "root", *pass, *cryptpass;
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char * const *newargv;
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struct spwd *spw;
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struct passwd *pw;
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uid_t uid;
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int i;
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ARGBEGIN {
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case 'l':
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lflag = 1;
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break;
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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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;
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else if (argc == 1)
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usr = argv[0];
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else
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usage();
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errno = 0;
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spw = getspnam(usr);
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if (errno)
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eprintf("getspnam: %s:", usr);
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else if (!spw)
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enprintf(EXIT_FAILURE, "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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enprintf(EXIT_FAILURE, "Denied\n");
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case '$':
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break;
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default:
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enprintf(EXIT_FAILURE, "Invalid shadow record\n");
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}
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uid = getuid();
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if (uid) {
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pass = getpass("Password: ");
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if (!pass)
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eprintf("getpass:");
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cryptpass = crypt(pass, spw->sp_pwdp);
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for (i = 0; pass[i]; i++)
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pass[i] = '\0';
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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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enprintf(EXIT_FAILURE, "Denied\n");
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}
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errno = 0;
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pw = getpwnam(usr);
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if (errno)
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eprintf("getpwnam: %s", usr);
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else if (!pw)
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enprintf(EXIT_FAILURE, "who are you?\n");
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if (initgroups(usr, pw->pw_gid) < 0)
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eprintf("initgroups:");
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if (setgid(pw->pw_gid) < 0)
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eprintf("setgid:");
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if (setuid(pw->pw_uid) < 0)
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eprintf("setuid:");
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if (lflag) {
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dologin(pw);
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} else {
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newargv = (char *const[]){pw->pw_shell, NULL};
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if (!pflag) {
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setenv("HOME", pw->pw_dir, 1);
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setenv("SHELL", pw->pw_shell, 1);
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if (strcmp(pw->pw_name, "root") != 0) {
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setenv("USER", pw->pw_name, 1);
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setenv("LOGNAME", pw->pw_name, 1);
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}
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}
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if (strcmp(pw->pw_name, "root") == 0)
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setenv("PATH", ENV_SUPATH, 1);
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else
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setenv("PATH", ENV_PATH, 1);
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execve(pflag ? getenv("SHELL") : pw->pw_shell,
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newargv, environ);
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}
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return (errno == ENOENT) ? 127 : 126;
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}
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static char *
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msetenv(const char *name, const char *value)
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{
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char *buf;
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size_t sz;
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sz = strlen(name) + strlen(value) + 2;
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buf = malloc(sz);
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if (!buf)
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eprintf("malloc:");
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snprintf(buf, sz, "%s=%s", name, value);
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return buf;
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}
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static void
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dologin(struct passwd *pw)
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{
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char shbuf[strlen(pw->pw_shell) + 1];
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char * const *newargv;
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char * const *newenv;
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strcpy(shbuf, pw->pw_shell);
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newargv = (char *const[]){shbuf, NULL};
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newenv = (char *const[]){
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msetenv("HOME", pw->pw_dir),
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msetenv("SHELL", pw->pw_shell),
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msetenv("USER", pw->pw_name),
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msetenv("LOGNAME", pw->pw_name),
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msetenv("TERM", getenv("TERM")),
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msetenv("PATH",
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strcmp(pw->pw_name, "root") == 0 ?
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ENV_SUPATH : ENV_PATH),
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NULL
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};
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if (chdir(pw->pw_dir) < 0)
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eprintf("chdir %s:", pw->pw_dir);
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execve(pw->pw_shell, newargv, newenv);
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}
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