150 lines
3.3 KiB
C
150 lines
3.3 KiB
C
/* su - become super-user Author: Patrick van Kleef */
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#include <sys/types.h>
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#include <pwd.h>
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#include <grp.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 <unistd.h>
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#include <limits.h>
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#include <fcntl.h>
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#include <time.h>
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#if __minix_vmd
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#include <sys/syslog.h>
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#endif
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#include <minix/minlib.h>
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int main(int argc, char **argv);
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int main(argc, argv)
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int argc;
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char *argv[];
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{
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register char *name, *password;
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char *shell, sh0[100];
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char from_user[8+1], from_shell[100];
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register struct passwd *pwd;
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char USER[20], LOGNAME[25], HOME[100], SHELL[100];
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char *envv[20], **envp;
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int smallenv;
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char *p;
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int super;
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int loginshell;
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gid_t groups[NGROUPS_MAX];
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int ngroups;
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int g;
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smallenv = 0;
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loginshell = 0;
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if (argc > 1 && (strcmp(argv[1], "-") == 0 || strcmp(argv[1], "-e") == 0)) {
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if (argv[1][1] == 0)
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loginshell= 1; /* 'su -' reads .profile */
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argv[1] = argv[0];
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argv++;
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argc--;
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smallenv = 1; /* Use small environment. */
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}
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if (argc > 1) {
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if (argv[1][0] == '-') {
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fprintf(stderr,
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"Usage: su [-[e]] [user [shell-arguments ...]]\n");
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exit(1);
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}
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name = argv[1];
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argv[1] = argv[0];
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argv++;
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} else {
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name = "root";
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}
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if ((pwd = getpwuid(getuid())) == 0) {
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fprintf(stderr, "You do not exist\n");
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exit(1);
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}
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strncpy(from_user, pwd->pw_name, 8);
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from_user[8]= 0;
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strncpy(from_shell, pwd->pw_shell[0] == '\0' ? "/bin/sh" : pwd->pw_shell,
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sizeof(from_shell)-1);
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from_shell[sizeof(from_shell)-1]= 0;
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if ((pwd = getpwnam(name)) == 0) {
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fprintf(stderr, "Unknown id: %s\n", name);
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exit(1);
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}
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super = 0;
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if (getgid() == 0) super = 1;
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ngroups = getgroups(NGROUPS_MAX, groups);
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for (g = 0; g < ngroups; g++) if (groups[g] == 0) super = 1;
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if (!super && strcmp(pwd->pw_passwd, crypt("", pwd->pw_passwd)) != 0) {
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#if __minix_vmd
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openlog("su", 0, LOG_AUTH);
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#endif
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password = getpass("Password:");
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if (password == 0
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|| strcmp(pwd->pw_passwd, crypt(password, pwd->pw_passwd)) != 0) {
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if (password != 0 && *password != 0) {
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#if __minix_vmd
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syslog(LOG_WARNING, "su %s failed for %s",
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name, from_user);
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#endif
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}
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fprintf(stderr, "Sorry\n");
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exit(2);
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}
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#if __minix_vmd
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syslog(LOG_NOTICE, "su %s succeeded for %s", name, from_user);
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closelog();
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#endif
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}
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initgroups(pwd->pw_name, pwd->pw_gid);
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setgid(pwd->pw_gid);
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setuid(pwd->pw_uid);
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if (loginshell) {
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shell = pwd->pw_shell[0] == '\0' ? "/bin/sh" : pwd->pw_shell;
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} else {
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if ((shell = getenv("SHELL")) == NULL) shell = from_shell;
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}
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if ((p= strrchr(shell, '/')) == 0) p= shell; else p++;
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sh0[0]= '-';
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strcpy(loginshell ? sh0+1 : sh0, p);
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argv[0]= sh0;
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if (smallenv) {
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envp = envv;
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*envp++ = "PATH=:/bin:/usr/bin",
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strcpy(USER, "USER=");
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strcpy(USER + 5, name);
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*envp++ = USER;
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strcpy(LOGNAME, "LOGNAME=");
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strcpy(LOGNAME + 8, name);
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*envp++ = LOGNAME;
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strcpy(SHELL, "SHELL=");
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strcpy(SHELL + 6, shell);
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*envp++ = SHELL;
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strcpy(HOME, "HOME=");
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strcpy(HOME + 5, pwd->pw_dir);
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*envp++ = HOME;
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if ((p = getenv("TERM")) != NULL) {
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*envp++ = p - 5;
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}
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if ((p = getenv("TERMCAP")) != NULL) {
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*envp++ = p - 8;
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}
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if ((p = getenv("TZ")) != NULL) {
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*envp++ = p - 3;
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}
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*envp = NULL;
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(void) chdir(pwd->pw_dir);
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execve(shell, argv, envv);
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perror(shell);
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} else {
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execv(shell, argv);
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perror(shell);
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}
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fprintf(stderr, "No shell\n");
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return(3);
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}
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