-/* su for GNU. Run a shell with substitute user and group IDs.
- Copyright (C) 92, 93, 94, 95, 1996 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+#include "su-common.h"
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
-
-/* Run a shell with the real and effective UID and GID and groups
- of USER, default `root'.
-
- The shell run is taken from USER's password entry, /bin/sh if
- none is specified there. If the account has a password, su
- prompts for a password unless run by a user with real UID 0.
-
- Does not change the current directory.
- Sets `HOME' and `SHELL' from the password entry for USER, and if
- USER is not root, sets `USER' and `LOGNAME' to USER.
- The subshell is not a login shell.
-
- If one or more ARGs are given, they are passed as additional
- arguments to the subshell.
-
- Does not handle /bin/sh or other shells specially
- (setting argv[0] to "-su", passing -c only to certain shells, etc.).
- I don't see the point in doing that, and it's ugly.
-
- This program intentionally does not support a "wheel group" that
- restricts who can su to UID 0 accounts. RMS considers that to
- be fascist.
-
- Options:
- -, -l, --login Make the subshell a login shell.
- Unset all environment variables except
- TERM, HOME and SHELL (set as above), and USER
- and LOGNAME (set unconditionally as above), and
- set PATH to a default value.
- Change to USER's home directory.
- Prepend "-" to the shell's name.
- -c, --commmand=COMMAND
- Pass COMMAND to the subshell with a -c option
- instead of starting an interactive shell.
- -f, --fast Pass the -f option to the subshell.
- -m, -p, --preserve-environment
- Do not change HOME, USER, LOGNAME, SHELL.
- Run $SHELL instead of USER's shell from /etc/passwd
- unless not the superuser and USER's shell is
- restricted.
- Overridden by --login and --shell.
- -s, --shell=shell Run SHELL instead of USER's shell from /etc/passwd
- unless not the superuser and USER's shell is
- restricted.
-
- Compile-time options:
- -DSYSLOG_SUCCESS Log successful su's (by default, to root) with syslog.
- -DSYSLOG_FAILURE Log failed su's (by default, to root) with syslog.
-
- -DSYSLOG_NON_ROOT Log all su's, not just those to root (UID 0).
- Never logs attempted su's to nonexistent accounts.
-
- Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
-
-#include <config.h>
-#include <stdio.h>
-#include <getopt.h>
-#include <sys/types.h>
-#include <pwd.h>
-#include <grp.h>
-#include "system.h"
-
-#if defined(HAVE_SYSLOG_H) && defined(HAVE_SYSLOG)
-#include <syslog.h>
-#else /* !HAVE_SYSLOG_H */
-#ifdef SYSLOG_SUCCESS
-#undef SYSLOG_SUCCESS
-#endif
-#ifdef SYSLOG_FAILURE
-#undef SYSLOG_FAILURE
-#endif
-#ifdef SYSLOG_NON_ROOT
-#undef SYSLOG_NON_ROOT
-#endif
-#endif /* !HAVE_SYSLOG_H */
-
-#ifdef _POSIX_VERSION
-#include <limits.h>
-#else /* not _POSIX_VERSION */
-struct passwd *getpwuid ();
-struct group *getgrgid ();
-uid_t getuid ();
-#include <sys/param.h>
-#endif /* not _POSIX_VERSION */
-
-#ifndef HAVE_ENDGRENT
-# define endgrent() ((void) 0)
-#endif
-
-#ifndef HAVE_ENDPWENT
-# define endpwent() ((void) 0)
-#endif
-
-#ifdef HAVE_SHADOW_H
-#include <shadow.h>
-#endif
-
-#include "error.h"
-
-/* The default PATH for simulated logins to non-superuser accounts. */
-#define DEFAULT_LOGIN_PATH ":/usr/ucb:/bin:/usr/bin"
-
-/* The default PATH for simulated logins to superuser accounts. */
-#define DEFAULT_ROOT_LOGIN_PATH "/usr/ucb:/bin:/usr/bin:/etc"
-
-/* The shell to run if none is given in the user's passwd entry. */
-#define DEFAULT_SHELL "/bin/sh"
-
-/* The user to become if none is specified. */
-#define DEFAULT_USER "root"
-
-char *crypt ();
-char *getpass ();
-char *getusershell ();
-void endusershell ();
-void setusershell ();
-
-char *basename ();
-char *xmalloc ();
-char *xrealloc ();
-char *xstrdup ();
-
-extern char **environ;
-
-/* The name this program was run with. */
-char *program_name;
-
-/* If nonzero, display usage information and exit. */
-static int show_help;
-
-/* If nonzero, print the version on standard output and exit. */
-static int show_version;
-
-/* If nonzero, pass the `-f' option to the subshell. */
-static int fast_startup;
-
-/* If nonzero, simulate a login instead of just starting a shell. */
-static int simulate_login;
-
-/* If nonzero, change some environment vars to indicate the user su'd to. */
-static int change_environment;
-
-static struct option const longopts[] =
-{
- {"command", required_argument, 0, 'c'},
- {"fast", no_argument, &fast_startup, 1},
- {"help", no_argument, &show_help, 1},
- {"login", no_argument, &simulate_login, 1},
- {"preserve-environment", no_argument, &change_environment, 0},
- {"shell", required_argument, 0, 's'},
- {"version", no_argument, &show_version, 1},
- {0, 0, 0, 0}
-};
-
-/* Add VAL to the environment, checking for out of memory errors. */
-
-static void
-xputenv (const char *val)
-{
- if (putenv (val))
- error (1, 0, _("virtual memory exhausted"));
-}
-
-/* Return a newly-allocated string whose contents concatenate
- those of S1, S2, S3. */
-
-static char *
-concat (const char *s1, const char *s2, const char *s3)
+int main(int argc, char **argv)
{
- int len1 = strlen (s1), len2 = strlen (s2), len3 = strlen (s3);
- char *result = (char *) xmalloc (len1 + len2 + len3 + 1);
-
- strcpy (result, s1);
- strcpy (result + len1, s2);
- strcpy (result + len1 + len2, s3);
- result[len1 + len2 + len3] = 0;
-
- return result;
-}
-
-/* Return the number of elements in ARR, a null-terminated array. */
-
-static int
-elements (char **arr)
-{
- int n = 0;
-
- for (n = 0; *arr; ++arr)
- ++n;
- return n;
-}
-
-#if defined (SYSLOG_SUCCESS) || defined (SYSLOG_FAILURE)
-/* Log the fact that someone has run su to the user given by PW;
- if SUCCESSFUL is nonzero, they gave the correct password, etc. */
-
-static void
-log_su (const struct passwd *pw, int successful)
-{
- const char *new_user, *old_user, *tty;
-
-#ifndef SYSLOG_NON_ROOT
- if (pw->pw_uid)
- return;
-#endif
- new_user = pw->pw_name;
- /* The utmp entry (via getlogin) is probably the best way to identify
- the user, especially if someone su's from a su-shell. */
- old_user = getlogin ();
- if (old_user == NULL)
- old_user = "";
- tty = ttyname (2);
- if (tty == NULL)
- tty = "";
- /* 4.2BSD openlog doesn't have the third parameter. */
- openlog (basename (program_name), 0
-#ifdef LOG_AUTH
- , LOG_AUTH
-#endif
- );
- syslog (LOG_NOTICE,
-#ifdef SYSLOG_NON_ROOT
- "%s(to %s) %s on %s",
-#else
- "%s%s on %s",
-#endif
- successful ? "" : "FAILED SU ",
-#ifdef SYSLOG_NON_ROOT
- new_user,
-#endif
- old_user, tty);
- closelog ();
+ return su_main(argc, argv, SU_MODE);
}
-#endif
-/* Ask the user for a password.
- Return 1 if the user gives the correct password for entry PW,
- 0 if not. Return 1 without asking for a password if run by UID 0
- or if PW has an empty password. */
-
-static int
-correct_password (const struct passwd *pw)
-{
- char *unencrypted, *encrypted, *correct;
-#ifdef HAVE_SHADOW_H
- /* Shadow passwd stuff for SVR3 and maybe other systems. */
- struct spwd *sp = getspnam (pw->pw_name);
-
- endspent ();
- if (sp)
- correct = sp->sp_pwdp;
- else
-#endif
- correct = pw->pw_passwd;
-
- if (getuid () == 0 || correct == 0 || correct[0] == '\0')
- return 1;
-
- unencrypted = getpass (_("Password:"));
- if (unencrypted == NULL)
- {
- error (0, 0, _("getpass: cannot open /dev/tty"));
- return 0;
- }
- encrypted = crypt (unencrypted, correct);
- memset (unencrypted, 0, strlen (unencrypted));
- return strcmp (encrypted, correct) == 0;
-}
-
-/* Update `environ' for the new shell based on PW, with SHELL being
- the value for the SHELL environment variable. */
-
-static void
-modify_environment (const struct passwd *pw, const char *shell)
-{
- char *term;
-
- if (simulate_login)
- {
- /* Leave TERM unchanged. Set HOME, SHELL, USER, LOGNAME, PATH.
- Unset all other environment variables. */
- term = getenv ("TERM");
- environ = (char **) xmalloc (2 * sizeof (char *));
- environ[0] = 0;
- if (term)
- xputenv (concat ("TERM", "=", term));
- xputenv (concat ("HOME", "=", pw->pw_dir));
- xputenv (concat ("SHELL", "=", shell));
- xputenv (concat ("USER", "=", pw->pw_name));
- xputenv (concat ("LOGNAME", "=", pw->pw_name));
- xputenv (concat ("PATH", "=", pw->pw_uid
- ? DEFAULT_LOGIN_PATH : DEFAULT_ROOT_LOGIN_PATH));
- }
- else
- {
- /* Set HOME, SHELL, and if not becoming a super-user,
- USER and LOGNAME. */
- if (change_environment)
- {
- xputenv (concat ("HOME", "=", pw->pw_dir));
- xputenv (concat ("SHELL", "=", shell));
- if (pw->pw_uid)
- {
- xputenv (concat ("USER", "=", pw->pw_name));
- xputenv (concat ("LOGNAME", "=", pw->pw_name));
- }
- }
- }
-}
-
-/* Become the user and group(s) specified by PW. */
-
-static void
-change_identity (const struct passwd *pw)
-{
-#ifdef HAVE_INITGROUPS
- errno = 0;
- if (initgroups (pw->pw_name, pw->pw_gid) == -1)
- error (1, errno, _("cannot set groups"));
- endgrent ();
-#endif
- if (setgid (pw->pw_gid))
- error (1, errno, _("cannot set group id"));
- if (setuid (pw->pw_uid))
- error (1, errno, _("cannot set user id"));
-}
-
-/* Run SHELL, or DEFAULT_SHELL if SHELL is empty.
- If COMMAND is nonzero, pass it to the shell with the -c option.
- If ADDITIONAL_ARGS is nonzero, pass it to the shell as more
- arguments. */
-
-static void
-run_shell (const char *shell, const char *command, char **additional_args)
-{
- const char **args;
- int argno = 1;
-
- if (additional_args)
- args = (const char **) xmalloc (sizeof (char *)
- * (10 + elements (additional_args)));
- else
- args = (const char **) xmalloc (sizeof (char *) * 10);
- if (simulate_login)
- {
- char *arg0;
- char *shell_basename;
-
- shell_basename = basename (shell);
- arg0 = xmalloc (strlen (shell_basename) + 2);
- arg0[0] = '-';
- strcpy (arg0 + 1, shell_basename);
- args[0] = arg0;
- }
- else
- args[0] = basename (shell);
- if (fast_startup)
- args[argno++] = "-f";
- if (command)
- {
- args[argno++] = "-c";
- args[argno++] = command;
- }
- if (additional_args)
- for (; *additional_args; ++additional_args)
- args[argno++] = *additional_args;
- args[argno] = NULL;
- execv (shell, (char **) args);
- error (1, errno, _("cannot run %s"), shell);
-}
-
-/* Return 1 if SHELL is a restricted shell (one not returned by
- getusershell), else 0, meaning it is a standard shell. */
-
-static int
-restricted_shell (const char *shell)
-{
- char *line;
-
- setusershell ();
- while ((line = getusershell ()) != NULL)
- {
- if (*line != '#' && strcmp (line, shell) == 0)
- {
- endusershell ();
- return 0;
- }
- }
- endusershell ();
- return 1;
-}
-
-static void
-usage (int status)
-{
- if (status != 0)
- fprintf (stderr, _("Try `%s --help' for more information.\n"),
- program_name);
- else
- {
- printf (_("Usage: %s [OPTION]... [-] [USER [ARG]...]\n"), program_name);
- printf (_("\
-Change the effective user id and group id to that of USER.\n\
-\n\
- -, -l, --login make the shell a login shell\n\
- -c, --commmand=COMMAND pass a single COMMAND to the shell with -c\n\
- -f, --fast pass -f to the shell (for csh or tcsh)\n\
- -m, --preserve-environment do not reset environment variables\n\
- -p same as -m\n\
- -s, --shell=SHELL run SHELL if /etc/shells allows it\n\
- --help display this help and exit\n\
- --version output version information and exit\n\
-\n\
-A mere - implies -l. If USER not given, assume root.\n\
-"));
- puts (_("\nReport bugs to bug-gnu-utils@gnu.ai.mit.edu"));
- }
- exit (status);
-}
-
-int
-main (int argc, char **argv)
-{
- int optc;
- const char *new_user = DEFAULT_USER;
- char *command = 0;
- char **additional_args = 0;
- char *shell = 0;
- struct passwd *pw;
- struct passwd pw_copy;
-
- program_name = argv[0];
- setlocale (LC_ALL, "");
- bindtextdomain (PACKAGE, LOCALEDIR);
- textdomain (PACKAGE);
-
- fast_startup = 0;
- simulate_login = 0;
- change_environment = 1;
-
- while ((optc = getopt_long (argc, argv, "c:flmps:", longopts, (int *) 0))
- != EOF)
- {
- switch (optc)
- {
- case 0:
- break;
-
- case 'c':
- command = optarg;
- break;
-
- case 'f':
- fast_startup = 1;
- break;
-
- case 'l':
- simulate_login = 1;
- break;
-
- case 'm':
- case 'p':
- change_environment = 0;
- break;
-
- case 's':
- shell = optarg;
- break;
-
- default:
- usage (1);
- }
- }
-
- if (show_version)
- {
- printf ("su (%s) %s\n", GNU_PACKAGE, VERSION);
- exit (0);
- }
-
- if (show_help)
- usage (0);
-
- if (optind < argc && !strcmp (argv[optind], "-"))
- {
- simulate_login = 1;
- ++optind;
- }
- if (optind < argc)
- new_user = argv[optind++];
- if (optind < argc)
- additional_args = argv + optind;
-
- pw = getpwnam (new_user);
- if (pw == 0)
- error (1, 0, _("user %s does not exist"), new_user);
- endpwent ();
-
- /* Make a copy of the password information and point pw at the local
- copy instead. Otherwise, some systems (e.g. Linux) would clobber
- the static data through the getlogin call from log_su. */
- pw_copy = *pw;
- pw = &pw_copy;
- pw->pw_name = xstrdup (pw->pw_name);
- pw->pw_dir = xstrdup (pw->pw_dir);
- pw->pw_shell = xstrdup (pw->pw_shell);
-
- if (!correct_password (pw))
- {
-#ifdef SYSLOG_FAILURE
- log_su (pw, 0);
-#endif
- error (1, 0, _("incorrect password"));
- }
-#ifdef SYSLOG_SUCCESS
- else
- {
- log_su (pw, 1);
- }
-#endif
-
- if (pw->pw_shell == 0 || pw->pw_shell[0] == 0)
- pw->pw_shell = (char *) DEFAULT_SHELL;
- if (shell == 0 && change_environment == 0)
- shell = getenv ("SHELL");
- if (shell != 0 && getuid () && restricted_shell (pw->pw_shell))
- {
- /* The user being su'd to has a nonstandard shell, and so is
- probably a uucp account or has restricted access. Don't
- compromise the account by allowing access with a standard
- shell. */
- error (0, 0, _("using restricted shell %s"), pw->pw_shell);
- shell = 0;
- }
- if (shell == 0)
- {
- shell = xstrdup (pw->pw_shell);
- }
- modify_environment (pw, shell);
-
- change_identity (pw);
- if (simulate_login && chdir (pw->pw_dir))
- error (0, errno, _("warning: cannot change directory to %s"), pw->pw_dir);
-
- run_shell (shell, command, additional_args);
-}
projects / thirdparty / util-linux.git / blobdiff