BSD 4_3 release

[unix-history] / usr / src / bin / su.c

/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980 Regents of the University of California.\n\
All rights reserved.\n";
#endif not lint

#ifndef lint
static char sccsid[] = "@(#)su.c        5.4 (Berkeley) 1/13/86";
#endif not lint

#include <stdio.h>
#include <pwd.h>
#include <grp.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>

char    userbuf[16]     = "USER=";
char    homebuf[128]    = "HOME=";
char    shellbuf[128]   = "SHELL=";
char    pathbuf[128]    = "PATH=:/usr/ucb:/bin:/usr/bin";
char    *cleanenv[] = { userbuf, homebuf, shellbuf, pathbuf, 0, 0 };
char    *user = "root";
char    *shell = "/bin/sh";
int     fulllogin;
int     fastlogin;

extern char     **environ;
struct  passwd *pwd;
char    *crypt();
char    *getpass();
char    *getenv();
char    *getlogin();

main(argc,argv)
       int argc;
       char *argv[];
{
       char *password;
       char buf[1000];
       FILE *fp;
       register char *p;

       openlog("su", LOG_ODELAY, LOG_AUTH);

again:
       if (argc > 1 && strcmp(argv[1], "-f") == 0) {
               fastlogin++;
               argc--, argv++;
               goto again;
       }
       if (argc > 1 && strcmp(argv[1], "-") == 0) {
               fulllogin++;
               argc--, argv++;
               goto again;
       }
       if (argc > 1 && argv[1][0] != '-') {
               user = argv[1];
               argc--, argv++;
       }
       if ((pwd = getpwuid(getuid())) == NULL) {
               fprintf(stderr, "Who are you?\n");
               exit(1);
       }
       strcpy(buf, pwd->pw_name);
       if ((pwd = getpwnam(user)) == NULL) {
               fprintf(stderr, "Unknown login: %s\n", user);
               exit(1);
       }
       /*
        * Only allow those in group zero to su to root.
        */
       if (pwd->pw_uid == 0) {
               struct  group *gr;
               int i;

               if ((gr = getgrgid(0)) != NULL) {
                       for (i = 0; gr->gr_mem[i] != NULL; i++)
                               if (strcmp(buf, gr->gr_mem[i]) == 0)
                                       goto userok;
                       fprintf(stderr, "You do not have permission to su %s\n",
                               user);
                       exit(1);
               }
       userok:
               setpriority(PRIO_PROCESS, 0, -2);
       }

#define Getlogin()  (((p = getlogin()) && *p) ? p : buf)
       if (pwd->pw_passwd[0] == '\0' || getuid() == 0)
               goto ok;
       password = getpass("Password:");
       if (strcmp(pwd->pw_passwd, crypt(password, pwd->pw_passwd)) != 0) {
               fprintf(stderr, "Sorry\n");
               if (pwd->pw_uid == 0) {
                       syslog(LOG_CRIT, "BAD SU %s on %s",
                                       Getlogin(), ttyname(2));
               }
               exit(2);
       }
ok:
       endpwent();
       if (pwd->pw_uid == 0) {
               syslog(LOG_NOTICE, "%s on %s", Getlogin(), ttyname(2));
               closelog();
       }
       if (setgid(pwd->pw_gid) < 0) {
               perror("su: setgid");
               exit(3);
       }
       if (initgroups(user, pwd->pw_gid)) {
               fprintf(stderr, "su: initgroups failed\n");
               exit(4);
       }
       if (setuid(pwd->pw_uid) < 0) {
               perror("su: setuid");
               exit(5);
       }
       if (pwd->pw_shell && *pwd->pw_shell)
               shell = pwd->pw_shell;
       if (fulllogin) {
               cleanenv[4] = getenv("TERM");
               environ = cleanenv;
       }
       if (strcmp(user, "root"))
               setenv("USER", pwd->pw_name, userbuf);
       setenv("SHELL", shell, shellbuf);
       setenv("HOME", pwd->pw_dir, homebuf);
       setpriority(PRIO_PROCESS, 0, 0);
       if (fastlogin) {
               *argv-- = "-f";
               *argv = "su";
       } else if (fulllogin) {
               if (chdir(pwd->pw_dir) < 0) {
                       fprintf(stderr, "No directory\n");
                       exit(6);
               }
               *argv = "-su";
       } else
               *argv = "su";
       execv(shell, argv);
       fprintf(stderr, "No shell\n");
       exit(7);
}

setenv(ename, eval, buf)
       char *ename, *eval, *buf;
{
       register char *cp, *dp;
       register char **ep = environ;

       /*
        * this assumes an environment variable "ename" already exists
        */
       while (dp = *ep++) {
               for (cp = ename; *cp == *dp && *cp; cp++, dp++)
                       continue;
               if (*cp == 0 && (*dp == '=' || *dp == 0)) {
                       strcat(buf, eval);
                       *--ep = buf;
                       return;
               }
       }
}

char *
getenv(ename)
       char *ename;
{
       register char *cp, *dp;
       register char **ep = environ;

       while (dp = *ep++) {
               for (cp = ename; *cp == *dp && *cp; cp++, dp++)
                       continue;
               if (*cp == 0 && (*dp == '=' || *dp == 0))
                       return (*--ep);
       }
       return ((char *)0);
}