su: move generic su code to su-common.c
Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
parent
8528ea2f81
commit
cf1a99dacc
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@ -82,6 +82,8 @@ if BUILD_SU
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bin_PROGRAMS += su
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su_SOURCES = \
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login-utils/su.c \
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login-utils/su-common.c \
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login-utils/su-common.h \
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login-utils/logindefs.c \
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login-utils/logindefs.h
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su_CFLAGS = $(SUID_CFLAGS) $(AM_CFLAGS)
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@ -0,0 +1,883 @@
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/* su for Linux. Run a shell with substitute user and group IDs.
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Copyright (C) 1992-2006 Free Software Foundation, Inc.
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Copyright (C) 2012 SUSE Linux Products GmbH, Nuernberg
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* Run a shell with the real and effective UID and GID and groups
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of USER, default `root'.
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The shell run is taken from USER's password entry, /bin/sh if
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none is specified there. If the account has a password, su
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prompts for a password unless run by a user with real UID 0.
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Does not change the current directory.
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Sets `HOME' and `SHELL' from the password entry for USER, and if
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USER is not root, sets `USER' and `LOGNAME' to USER.
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The subshell is not a login shell.
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If one or more ARGs are given, they are passed as additional
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arguments to the subshell.
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Does not handle /bin/sh or other shells specially
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(setting argv[0] to "-su", passing -c only to certain shells, etc.).
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I don't see the point in doing that, and it's ugly.
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Based on an implemenation by David MacKenzie <djm@gnu.ai.mit.edu>. */
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enum
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{
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EXIT_CANNOT_INVOKE = 126,
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EXIT_ENOENT = 127
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};
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#include <config.h>
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#include <stdio.h>
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#include <getopt.h>
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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 <security/pam_appl.h>
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#include <security/pam_misc.h>
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#include <signal.h>
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#include <sys/wait.h>
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#include <syslog.h>
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#include "err.h"
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#include <stdbool.h>
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#include "c.h"
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#include "xalloc.h"
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#include "nls.h"
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#include "pathnames.h"
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#include "env.h"
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/* name of the pam configuration files. separate configs for su and su - */
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#define PAM_SERVICE_NAME "su"
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#define PAM_SERVICE_NAME_L "su-l"
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#define is_pam_failure(_rc) ((_rc) != PAM_SUCCESS)
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#include "logindefs.h"
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#include "su-common.h"
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/* The shell to run if none is given in the user's passwd entry. */
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#define DEFAULT_SHELL "/bin/sh"
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/* The user to become if none is specified. */
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#define DEFAULT_USER "root"
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#ifndef HAVE_ENVIRON_DECL
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extern char **environ;
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#endif
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static void run_shell (char const *, char const *, char **, size_t)
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__attribute__ ((__noreturn__));
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/* If true, pass the `-f' option to the subshell. */
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static bool fast_startup;
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/* If true, simulate a login instead of just starting a shell. */
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static bool simulate_login;
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/* If true, change some environment vars to indicate the user su'd to. */
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static bool change_environment;
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/* If true, then don't call setsid() with a command. */
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static int same_session = 0;
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/* SU_MODE_{RUNUSER,SU} */
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static int su_mode;
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static bool _pam_session_opened;
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static bool _pam_cred_established;
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static sig_atomic_t volatile caught_signal = false;
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static pam_handle_t *pamh = NULL;
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static struct option const longopts[] =
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{
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{"command", required_argument, NULL, 'c'},
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{"session-command", required_argument, NULL, 'C'},
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{"fast", no_argument, NULL, 'f'},
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{"login", no_argument, NULL, 'l'},
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{"preserve-environment", no_argument, NULL, 'p'},
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{"shell", required_argument, NULL, 's'},
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{"group", required_argument, NULL, 'g'},
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{"supp-group", required_argument, NULL, 'G'},
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{"help", no_argument, 0, 'h'},
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{"version", no_argument, 0, 'V'},
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{NULL, 0, NULL, 0}
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};
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/* Log the fact that someone has run su to the user given by PW;
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if SUCCESSFUL is true, they gave the correct password, etc. */
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static void
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log_su (struct passwd const *pw, bool successful)
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{
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const char *new_user, *old_user, *tty;
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new_user = pw->pw_name;
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/* The utmp entry (via getlogin) is probably the best way to identify
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the user, especially if someone su's from a su-shell. */
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old_user = getlogin ();
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if (!old_user)
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{
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/* getlogin can fail -- usually due to lack of utmp entry.
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Resort to getpwuid. */
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struct passwd *pwd = getpwuid (getuid ());
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old_user = (pwd ? pwd->pw_name : "");
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}
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tty = ttyname (STDERR_FILENO);
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if (!tty)
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tty = "none";
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openlog (program_invocation_short_name, 0 , LOG_AUTH);
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syslog (LOG_NOTICE, "%s(to %s) %s on %s",
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successful ? "" : "FAILED SU ",
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new_user, old_user, tty);
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closelog ();
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}
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static struct pam_conv conv =
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{
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misc_conv,
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NULL
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};
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static void
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cleanup_pam (int retcode)
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{
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int saved_errno = errno;
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if (_pam_session_opened)
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pam_close_session (pamh, 0);
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if (_pam_cred_established)
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pam_setcred (pamh, PAM_DELETE_CRED | PAM_SILENT);
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pam_end(pamh, retcode);
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errno = saved_errno;
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}
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/* Signal handler for parent process. */
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static void
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su_catch_sig (int sig __attribute__((__unused__)))
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{
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caught_signal = true;
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}
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/* Export env variables declared by PAM modules. */
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static void
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export_pamenv (void)
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{
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char **env;
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/* This is a copy but don't care to free as we exec later anyways. */
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env = pam_getenvlist (pamh);
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while (env && *env)
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{
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if (putenv (*env) != 0)
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err (EXIT_FAILURE, NULL);
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env++;
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}
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}
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static void
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create_watching_parent (void)
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{
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pid_t child;
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sigset_t ourset;
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int status = 0;
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int retval;
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retval = pam_open_session (pamh, 0);
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if (is_pam_failure(retval))
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{
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cleanup_pam (retval);
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errx (EXIT_FAILURE, _("cannot not open session: %s"),
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pam_strerror (pamh, retval));
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}
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else
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_pam_session_opened = 1;
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child = fork ();
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if (child == (pid_t) -1)
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{
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cleanup_pam (PAM_ABORT);
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err (EXIT_FAILURE, _("cannot create child process"));
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}
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/* the child proceeds to run the shell */
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if (child == 0)
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return;
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/* In the parent watch the child. */
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/* su without pam support does not have a helper that keeps
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sitting on any directory so let's go to /. */
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if (chdir ("/") != 0)
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warn (_("cannot change directory to %s"), "/");
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sigfillset (&ourset);
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if (sigprocmask (SIG_BLOCK, &ourset, NULL))
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{
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warn (_("cannot block signals"));
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caught_signal = true;
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}
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if (!caught_signal)
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{
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struct sigaction action;
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action.sa_handler = su_catch_sig;
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sigemptyset (&action.sa_mask);
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action.sa_flags = 0;
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sigemptyset (&ourset);
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if (!same_session)
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{
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if (sigaddset(&ourset, SIGINT) || sigaddset(&ourset, SIGQUIT))
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{
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warn (_("cannot set signal handler"));
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caught_signal = true;
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}
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}
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if (!caught_signal && (sigaddset(&ourset, SIGTERM)
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|| sigaddset(&ourset, SIGALRM)
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|| sigaction(SIGTERM, &action, NULL)
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|| sigprocmask(SIG_UNBLOCK, &ourset, NULL))) {
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warn (_("cannot set signal handler"));
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caught_signal = true;
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}
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if (!caught_signal && !same_session && (sigaction(SIGINT, &action, NULL)
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|| sigaction(SIGQUIT, &action, NULL)))
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{
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warn (_("cannot set signal handler"));
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caught_signal = true;
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}
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}
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if (!caught_signal)
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{
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pid_t pid;
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for (;;)
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{
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pid = waitpid (child, &status, WUNTRACED);
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if (pid != (pid_t)-1 && WIFSTOPPED (status))
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{
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kill (getpid (), SIGSTOP);
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/* once we get here, we must have resumed */
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kill (pid, SIGCONT);
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}
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else
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break;
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}
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if (pid != (pid_t)-1)
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if (WIFSIGNALED (status))
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status = WTERMSIG (status) + 128;
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else
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status = WEXITSTATUS (status);
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else
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status = 1;
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}
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else
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status = 1;
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if (caught_signal)
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{
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fprintf (stderr, _("\nSession terminated, killing shell..."));
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kill (child, SIGTERM);
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}
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cleanup_pam (PAM_SUCCESS);
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if (caught_signal)
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{
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sleep (2);
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kill (child, SIGKILL);
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fprintf (stderr, _(" ...killed.\n"));
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}
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exit (status);
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}
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static void
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authenticate (const struct passwd *pw)
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{
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const struct passwd *lpw;
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const char *cp;
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int retval;
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retval = pam_start (simulate_login ? PAM_SERVICE_NAME_L : PAM_SERVICE_NAME,
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pw->pw_name, &conv, &pamh);
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if (is_pam_failure(retval))
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goto done;
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if (isatty (0) && (cp = ttyname (0)) != NULL)
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{
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const char *tty;
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if (strncmp (cp, "/dev/", 5) == 0)
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tty = cp + 5;
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else
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tty = cp;
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retval = pam_set_item (pamh, PAM_TTY, tty);
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if (is_pam_failure(retval))
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goto done;
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}
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lpw = getpwuid (getuid ());
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if (lpw && lpw->pw_name)
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{
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retval = pam_set_item (pamh, PAM_RUSER, (const void *) lpw->pw_name);
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if (is_pam_failure(retval))
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goto done;
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}
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retval = pam_authenticate (pamh, 0);
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if (is_pam_failure(retval))
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goto done;
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retval = pam_acct_mgmt (pamh, 0);
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if (retval == PAM_NEW_AUTHTOK_REQD)
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{
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/* Password has expired. Offer option to change it. */
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retval = pam_chauthtok (pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
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}
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done:
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log_su (pw, !is_pam_failure(retval));
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if (is_pam_failure(retval))
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{
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const char *msg = pam_strerror(pamh, retval);
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pam_end(pamh, retval);
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sleep (getlogindefs_num ("FAIL_DELAY", 1));
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errx (EXIT_FAILURE, "%s", msg?msg:_("incorrect password"));
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}
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}
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/* Add or clear /sbin and /usr/sbin for the su command
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used without `-'. */
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/* Set if /sbin is found in path. */
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#define SBIN_MASK 0x01
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/* Set if /usr/sbin is found in path. */
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#define USBIN_MASK 0x02
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static char *
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addsbin (const char *const path)
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{
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unsigned char smask = 0;
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char *ptr, *tmp, *cur, *ret = NULL;
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size_t len;
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if (!path || *path == 0)
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return NULL;
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tmp = xstrdup (path);
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cur = tmp;
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for (ptr = strsep (&cur, ":"); ptr != NULL; ptr = strsep (&cur, ":"))
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{
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if (!strcmp (ptr, "/sbin"))
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smask |= SBIN_MASK;
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if (!strcmp (ptr, "/usr/sbin"))
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smask |= USBIN_MASK;
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}
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if ((smask & (USBIN_MASK|SBIN_MASK)) == (USBIN_MASK|SBIN_MASK))
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{
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free (tmp);
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return NULL;
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}
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len = strlen (path);
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if (!(smask & USBIN_MASK))
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len += strlen ("/usr/sbin:");
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if (!(smask & SBIN_MASK))
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len += strlen (":/sbin");
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ret = xmalloc (len + 1);
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strcpy (tmp, path);
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*ret = 0;
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cur = tmp;
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for (ptr = strsep (&cur, ":"); ptr; ptr = strsep (&cur, ":"))
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{
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if (!strcmp (ptr, "."))
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continue;
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if (*ret)
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strcat (ret, ":");
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if (!(smask & USBIN_MASK) && !strcmp (ptr, "/bin"))
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{
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strcat (ret, "/usr/sbin:");
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strcat (ret, ptr);
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smask |= USBIN_MASK;
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continue;
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}
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if (!(smask & SBIN_MASK) && !strcmp (ptr, "/usr/bin"))
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{
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strcat (ret, ptr);
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strcat (ret, ":/sbin");
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smask |= SBIN_MASK;
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continue;
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}
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strcat (ret, ptr);
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}
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free (tmp);
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if (!(smask & USBIN_MASK))
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strcat (ret, ":/usr/sbin");
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if (!(smask & SBIN_MASK))
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strcat (ret, ":/sbin");
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return ret;
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}
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static char *
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clearsbin (const char *const path)
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{
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char *ptr, *tmp, *cur, *ret = NULL;
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if (!path || *path == 0)
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return NULL;
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tmp = xstrdup (path);
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ret = xmalloc (strlen (path) + 1);
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*ret = 0;
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cur = tmp;
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for (ptr = strsep (&cur, ":"); ptr; ptr = strsep (&cur, ":"))
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{
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if (!strcmp (ptr, "/sbin"))
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continue;
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if (!strcmp (ptr, "/usr/sbin"))
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continue;
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if (!strcmp (ptr, "/usr/local/sbin"))
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continue;
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if (*ret)
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strcat (ret, ":");
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strcat (ret, ptr);
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}
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free (tmp);
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return ret;
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}
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static void
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set_path(const struct passwd* pw)
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{
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int r;
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if (pw->pw_uid)
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r = logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH);
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else if ((r = logindefs_setenv("PATH", "ENV_ROOTPATH", NULL)) != 0)
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r = logindefs_setenv("PATH", "ENV_SUPATH", _PATH_DEFPATH_ROOT);
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if (r != 0)
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err (EXIT_FAILURE, _("failed to set PATH"));
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}
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/* Update `environ' for the new shell based on PW, with SHELL being
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the value for the SHELL environment variable. */
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static void
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modify_environment (const struct passwd *pw, const char *shell)
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{
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if (simulate_login)
|
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{
|
||||
/* Leave TERM unchanged. Set HOME, SHELL, USER, LOGNAME, PATH.
|
||||
Unset all other environment variables. */
|
||||
char const *term = getenv ("TERM");
|
||||
if (term)
|
||||
term = xstrdup (term);
|
||||
environ = xmalloc ((6 + !!term) * sizeof (char *));
|
||||
environ[0] = NULL;
|
||||
if (term)
|
||||
xsetenv ("TERM", term, 1);
|
||||
xsetenv ("HOME", pw->pw_dir, 1);
|
||||
xsetenv ("SHELL", shell, 1);
|
||||
xsetenv ("USER", pw->pw_name, 1);
|
||||
xsetenv ("LOGNAME", pw->pw_name, 1);
|
||||
set_path(pw);
|
||||
}
|
||||
else
|
||||
{
|
||||
/* Set HOME, SHELL, and if not becoming a super-user,
|
||||
USER and LOGNAME. */
|
||||
if (change_environment)
|
||||
{
|
||||
xsetenv ("HOME", pw->pw_dir, 1);
|
||||
xsetenv ("SHELL", shell, 1);
|
||||
if (getlogindefs_bool ("ALWAYS_SET_PATH", 0))
|
||||
set_path(pw);
|
||||
else
|
||||
{
|
||||
char const *path = getenv ("PATH");
|
||||
char *new = NULL;
|
||||
|
||||
if (pw->pw_uid)
|
||||
new = clearsbin (path);
|
||||
else
|
||||
new = addsbin (path);
|
||||
|
||||
if (new)
|
||||
{
|
||||
xsetenv ("PATH", new, 1);
|
||||
free (new);
|
||||
}
|
||||
}
|
||||
if (pw->pw_uid)
|
||||
{
|
||||
xsetenv ("USER", pw->pw_name, 1);
|
||||
xsetenv ("LOGNAME", pw->pw_name, 1);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
export_pamenv ();
|
||||
}
|
||||
|
||||
/* Become the user and group(s) specified by PW. */
|
||||
|
||||
static void
|
||||
init_groups (const struct passwd *pw, gid_t *groups, int num_groups)
|
||||
{
|
||||
int retval;
|
||||
|
||||
errno = 0;
|
||||
|
||||
if (num_groups)
|
||||
retval = setgroups (num_groups, groups);
|
||||
else
|
||||
retval = initgroups (pw->pw_name, pw->pw_gid);
|
||||
|
||||
if (retval == -1)
|
||||
{
|
||||
cleanup_pam (PAM_ABORT);
|
||||
err (EXIT_FAILURE, _("cannot set groups"));
|
||||
}
|
||||
endgrent ();
|
||||
|
||||
retval = pam_setcred (pamh, PAM_ESTABLISH_CRED);
|
||||
if (is_pam_failure(retval))
|
||||
errx (EXIT_FAILURE, "%s", pam_strerror (pamh, retval));
|
||||
else
|
||||
_pam_cred_established = 1;
|
||||
}
|
||||
|
||||
static void
|
||||
change_identity (const struct passwd *pw)
|
||||
{
|
||||
if (setgid (pw->pw_gid))
|
||||
err (EXIT_FAILURE, _("cannot set group id"));
|
||||
if (setuid (pw->pw_uid))
|
||||
err (EXIT_FAILURE, _("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.
|
||||
Pass ADDITIONAL_ARGS to the shell as more arguments; there
|
||||
are N_ADDITIONAL_ARGS extra arguments. */
|
||||
|
||||
static void
|
||||
run_shell (char const *shell, char const *command, char **additional_args,
|
||||
size_t n_additional_args)
|
||||
{
|
||||
size_t n_args = 1 + fast_startup + 2 * !!command + n_additional_args + 1;
|
||||
char const **args = xcalloc (n_args, sizeof *args);
|
||||
size_t argno = 1;
|
||||
|
||||
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;
|
||||
}
|
||||
memcpy (args + argno, additional_args, n_additional_args * sizeof *args);
|
||||
args[argno + n_additional_args] = NULL;
|
||||
execv (shell, (char **) args);
|
||||
|
||||
{
|
||||
int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
|
||||
warn ("%s", shell);
|
||||
exit (exit_status);
|
||||
}
|
||||
}
|
||||
|
||||
/* Return true if SHELL is a restricted shell (one not returned by
|
||||
getusershell), else false, meaning it is a standard shell. */
|
||||
|
||||
static bool
|
||||
restricted_shell (const char *shell)
|
||||
{
|
||||
char *line;
|
||||
|
||||
setusershell ();
|
||||
while ((line = getusershell ()) != NULL)
|
||||
{
|
||||
if (*line != '#' && !strcmp (line, shell))
|
||||
{
|
||||
endusershell ();
|
||||
return false;
|
||||
}
|
||||
}
|
||||
endusershell ();
|
||||
return true;
|
||||
}
|
||||
|
||||
static void __attribute__((__noreturn__))
|
||||
usage (int status)
|
||||
{
|
||||
if (status != EXIT_SUCCESS)
|
||||
fprintf (stderr, _("Try `%s --help' for more information.\n"),
|
||||
program_invocation_short_name);
|
||||
else
|
||||
{
|
||||
fputs(USAGE_HEADER, stdout);
|
||||
printf (_(" %s [options] [-] [USER [arg]...]\n"), program_invocation_short_name);
|
||||
fputs (_("\n\
|
||||
Change the effective user id and group id to that of USER.\n\
|
||||
A mere - implies -l. If USER not given, assume root.\n"), stdout);
|
||||
fputs(USAGE_OPTIONS, stdout);
|
||||
fputs (_("\
|
||||
-, -l, --login make the shell a login shell\n\
|
||||
-c, --command <command> pass a single command to the shell with -c\n\
|
||||
--session-command <command> pass a single command to the shell with -c\n\
|
||||
and do not create a new session\n\
|
||||
-g --group=group specify the primary group\n\
|
||||
-G --supp-group=group specify a supplemental group\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\
|
||||
"), stdout);
|
||||
|
||||
fputs(USAGE_SEPARATOR, stdout);
|
||||
fputs(USAGE_HELP, stdout);
|
||||
fputs(USAGE_VERSION, stdout);
|
||||
printf(USAGE_MAN_TAIL("su(1)"));
|
||||
}
|
||||
exit (status);
|
||||
}
|
||||
|
||||
static
|
||||
void load_config(void)
|
||||
{
|
||||
logindefs_load_file("/etc/default/su");
|
||||
logindefs_load_file(_PATH_LOGINDEFS);
|
||||
}
|
||||
|
||||
/*
|
||||
* Returns 1 if the current user is not root
|
||||
*/
|
||||
static int
|
||||
evaluate_uid(void)
|
||||
{
|
||||
uid_t ruid = getuid();
|
||||
uid_t euid = geteuid();
|
||||
|
||||
/* if we're really root and aren't running setuid */
|
||||
return (uid_t) 0 == ruid && ruid == euid ? 0 : 1;
|
||||
}
|
||||
|
||||
int
|
||||
su_main (int argc, char **argv, int mode)
|
||||
{
|
||||
int optc;
|
||||
const char *new_user = DEFAULT_USER;
|
||||
char *command = NULL;
|
||||
int request_same_session = 0;
|
||||
char *shell = NULL;
|
||||
struct passwd *pw;
|
||||
struct passwd pw_copy;
|
||||
struct group *gr;
|
||||
gid_t groups[NGROUPS_MAX];
|
||||
int num_supp_groups = 0;
|
||||
int use_gid = 0;
|
||||
int restricted;
|
||||
|
||||
setlocale (LC_ALL, "");
|
||||
bindtextdomain (PACKAGE, LOCALEDIR);
|
||||
textdomain (PACKAGE);
|
||||
|
||||
su_mode = mode;
|
||||
fast_startup = false;
|
||||
simulate_login = false;
|
||||
change_environment = true;
|
||||
|
||||
while ((optc = getopt_long (argc, argv, "c:fg:G:lmps:hV", longopts, NULL)) != -1)
|
||||
{
|
||||
switch (optc)
|
||||
{
|
||||
case 'c':
|
||||
command = optarg;
|
||||
break;
|
||||
|
||||
case 'C':
|
||||
command = optarg;
|
||||
request_same_session = 1;
|
||||
break;
|
||||
|
||||
case 'f':
|
||||
fast_startup = true;
|
||||
break;
|
||||
|
||||
case 'g':
|
||||
gr = getgrnam(optarg);
|
||||
if (!gr)
|
||||
errx(EXIT_FAILURE, _("group %s does not exist"), optarg);
|
||||
use_gid = 1;
|
||||
groups[0] = gr->gr_gid;
|
||||
break;
|
||||
|
||||
case 'G':
|
||||
num_supp_groups++;
|
||||
if (num_supp_groups >= NGROUPS_MAX)
|
||||
errx(EXIT_FAILURE,
|
||||
_("can't specify more than %d supplemental groups"),
|
||||
NGROUPS_MAX - 1);
|
||||
gr = getgrnam(optarg);
|
||||
if (!gr)
|
||||
errx(EXIT_FAILURE, _("group %s does not exist"), optarg);
|
||||
groups[num_supp_groups] = gr->gr_gid;
|
||||
break;
|
||||
|
||||
case 'l':
|
||||
simulate_login = true;
|
||||
break;
|
||||
|
||||
case 'm':
|
||||
case 'p':
|
||||
change_environment = false;
|
||||
break;
|
||||
|
||||
case 's':
|
||||
shell = optarg;
|
||||
break;
|
||||
|
||||
case 'h':
|
||||
usage(0);
|
||||
|
||||
case 'V':
|
||||
printf(UTIL_LINUX_VERSION);
|
||||
exit(EXIT_SUCCESS);
|
||||
|
||||
default:
|
||||
usage (EXIT_FAILURE);
|
||||
}
|
||||
}
|
||||
|
||||
restricted = evaluate_uid ();
|
||||
|
||||
if (optind < argc && !strcmp (argv[optind], "-"))
|
||||
{
|
||||
simulate_login = true;
|
||||
++optind;
|
||||
}
|
||||
if (optind < argc)
|
||||
new_user = argv[optind++];
|
||||
|
||||
if ((num_supp_groups || use_gid) && restricted)
|
||||
errx(EXIT_FAILURE, _("only root can specify alternative groups"));
|
||||
|
||||
logindefs_load_defaults = load_config;
|
||||
|
||||
pw = getpwnam (new_user);
|
||||
if (! (pw && pw->pw_name && pw->pw_name[0] && pw->pw_dir && pw->pw_dir[0]
|
||||
&& pw->pw_passwd))
|
||||
errx (EXIT_FAILURE, _("user %s does not exist"), new_user);
|
||||
|
||||
/* 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.
|
||||
Also, make sure pw->pw_shell is a nonempty string.
|
||||
It may be NULL when NEW_USER is a username that is retrieved via NIS (YP),
|
||||
but that doesn't have a default shell listed. */
|
||||
pw_copy = *pw;
|
||||
pw = &pw_copy;
|
||||
pw->pw_name = xstrdup (pw->pw_name);
|
||||
pw->pw_passwd = xstrdup (pw->pw_passwd);
|
||||
pw->pw_dir = xstrdup (pw->pw_dir);
|
||||
pw->pw_shell = xstrdup (pw->pw_shell && pw->pw_shell[0]
|
||||
? pw->pw_shell
|
||||
: DEFAULT_SHELL);
|
||||
endpwent ();
|
||||
|
||||
if (num_supp_groups && !use_gid)
|
||||
{
|
||||
pw->pw_gid = groups[1];
|
||||
memmove (groups, groups + 1, sizeof(gid_t) * num_supp_groups);
|
||||
}
|
||||
else if (use_gid)
|
||||
{
|
||||
pw->pw_gid = groups[0];
|
||||
num_supp_groups++;
|
||||
}
|
||||
|
||||
authenticate (pw);
|
||||
|
||||
if (request_same_session || !command || !pw->pw_uid)
|
||||
same_session = 1;
|
||||
|
||||
if (!shell && !change_environment)
|
||||
shell = getenv ("SHELL");
|
||||
if (shell && getuid () != 0 && 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. */
|
||||
warnx (_("using restricted shell %s"), pw->pw_shell);
|
||||
shell = NULL;
|
||||
}
|
||||
shell = xstrdup (shell ? shell : pw->pw_shell);
|
||||
|
||||
init_groups (pw, groups, num_supp_groups);
|
||||
|
||||
create_watching_parent ();
|
||||
/* Now we're in the child. */
|
||||
|
||||
change_identity (pw);
|
||||
if (!same_session)
|
||||
setsid ();
|
||||
|
||||
/* Set environment after pam_open_session, which may put KRB5CCNAME
|
||||
into the pam_env, etc. */
|
||||
|
||||
modify_environment (pw, shell);
|
||||
|
||||
if (simulate_login && chdir (pw->pw_dir) != 0)
|
||||
warn (_("warning: cannot change directory to %s"), pw->pw_dir);
|
||||
|
||||
run_shell (shell, command, argv + optind, max (0, argc - optind));
|
||||
}
|
||||
|
||||
// vim: sw=2 cinoptions=>4,n-2,{2,^-2,\:2,=2,g0,h2,p5,t0,+2,(0,u0,w1,m1
|
|
@ -0,0 +1,11 @@
|
|||
#ifndef UTIL_LINUX_SU_COMMON_H
|
||||
#define UTIL_LINUX_SU_COMMON_H
|
||||
|
||||
enum {
|
||||
SU_MODE,
|
||||
RUNUSER_MODE
|
||||
};
|
||||
|
||||
extern int su_main(int argc, char **argv, int mode);
|
||||
|
||||
#endif /* UTIL_LINUX_SU_COMMON */
|
876
login-utils/su.c
876
login-utils/su.c
|
@ -1,878 +1,8 @@
|
|||
/* su for Linux. Run a shell with substitute user and group IDs.
|
||||
Copyright (C) 1992-2006 Free Software Foundation, Inc.
|
||||
Copyright (C) 2012 SUSE Linux Products GmbH, Nuernberg
|
||||
|
||||
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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.
|
||||
|
||||
Based on an implemenation by David MacKenzie <djm@gnu.ai.mit.edu>. */
|
||||
|
||||
enum
|
||||
int main(int argv, char **argc)
|
||||
{
|
||||
EXIT_CANNOT_INVOKE = 126,
|
||||
EXIT_ENOENT = 127
|
||||
};
|
||||
|
||||
#include <config.h>
|
||||
#include <stdio.h>
|
||||
#include <getopt.h>
|
||||
#include <sys/types.h>
|
||||
#include <pwd.h>
|
||||
#include <grp.h>
|
||||
#include <security/pam_appl.h>
|
||||
#include <security/pam_misc.h>
|
||||
#include <signal.h>
|
||||
#include <sys/wait.h>
|
||||
#include <syslog.h>
|
||||
|
||||
#include "err.h"
|
||||
|
||||
#include <stdbool.h>
|
||||
#include "c.h"
|
||||
#include "xalloc.h"
|
||||
#include "nls.h"
|
||||
#include "pathnames.h"
|
||||
#include "env.h"
|
||||
|
||||
/* name of the pam configuration files. separate configs for su and su - */
|
||||
#define PAM_SERVICE_NAME "su"
|
||||
#define PAM_SERVICE_NAME_L "su-l"
|
||||
|
||||
#define is_pam_failure(_rc) ((_rc) != PAM_SUCCESS)
|
||||
|
||||
#include "logindefs.h"
|
||||
|
||||
/* 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"
|
||||
|
||||
#ifndef HAVE_ENVIRON_DECL
|
||||
extern char **environ;
|
||||
#endif
|
||||
|
||||
static void run_shell (char const *, char const *, char **, size_t)
|
||||
__attribute__ ((__noreturn__));
|
||||
|
||||
/* If true, pass the `-f' option to the subshell. */
|
||||
static bool fast_startup;
|
||||
|
||||
/* If true, simulate a login instead of just starting a shell. */
|
||||
static bool simulate_login;
|
||||
|
||||
/* If true, change some environment vars to indicate the user su'd to. */
|
||||
static bool change_environment;
|
||||
|
||||
/* If true, then don't call setsid() with a command. */
|
||||
int same_session = 0;
|
||||
|
||||
static bool _pam_session_opened;
|
||||
static bool _pam_cred_established;
|
||||
static sig_atomic_t volatile caught_signal = false;
|
||||
static pam_handle_t *pamh = NULL;
|
||||
|
||||
static struct option const longopts[] =
|
||||
{
|
||||
{"command", required_argument, NULL, 'c'},
|
||||
{"session-command", required_argument, NULL, 'C'},
|
||||
{"fast", no_argument, NULL, 'f'},
|
||||
{"login", no_argument, NULL, 'l'},
|
||||
{"preserve-environment", no_argument, NULL, 'p'},
|
||||
{"shell", required_argument, NULL, 's'},
|
||||
{"group", required_argument, NULL, 'g'},
|
||||
{"supp-group", required_argument, NULL, 'G'},
|
||||
{"help", no_argument, 0, 'h'},
|
||||
{"version", no_argument, 0, 'V'},
|
||||
{NULL, 0, NULL, 0}
|
||||
};
|
||||
|
||||
/* Log the fact that someone has run su to the user given by PW;
|
||||
if SUCCESSFUL is true, they gave the correct password, etc. */
|
||||
|
||||
static void
|
||||
log_su (struct passwd const *pw, bool successful)
|
||||
{
|
||||
const char *new_user, *old_user, *tty;
|
||||
|
||||
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)
|
||||
{
|
||||
/* getlogin can fail -- usually due to lack of utmp entry.
|
||||
Resort to getpwuid. */
|
||||
struct passwd *pwd = getpwuid (getuid ());
|
||||
old_user = (pwd ? pwd->pw_name : "");
|
||||
}
|
||||
tty = ttyname (STDERR_FILENO);
|
||||
if (!tty)
|
||||
tty = "none";
|
||||
|
||||
openlog (program_invocation_short_name, 0 , LOG_AUTH);
|
||||
syslog (LOG_NOTICE, "%s(to %s) %s on %s",
|
||||
successful ? "" : "FAILED SU ",
|
||||
new_user, old_user, tty);
|
||||
closelog ();
|
||||
return su_main(argv, argc, SU_MODE);
|
||||
}
|
||||
|
||||
static struct pam_conv conv =
|
||||
{
|
||||
misc_conv,
|
||||
NULL
|
||||
};
|
||||
|
||||
static void
|
||||
cleanup_pam (int retcode)
|
||||
{
|
||||
int saved_errno = errno;
|
||||
|
||||
if (_pam_session_opened)
|
||||
pam_close_session (pamh, 0);
|
||||
|
||||
if (_pam_cred_established)
|
||||
pam_setcred (pamh, PAM_DELETE_CRED | PAM_SILENT);
|
||||
|
||||
pam_end(pamh, retcode);
|
||||
|
||||
errno = saved_errno;
|
||||
}
|
||||
|
||||
/* Signal handler for parent process. */
|
||||
static void
|
||||
su_catch_sig (int sig __attribute__((__unused__)))
|
||||
{
|
||||
caught_signal = true;
|
||||
}
|
||||
|
||||
/* Export env variables declared by PAM modules. */
|
||||
static void
|
||||
export_pamenv (void)
|
||||
{
|
||||
char **env;
|
||||
|
||||
/* This is a copy but don't care to free as we exec later anyways. */
|
||||
env = pam_getenvlist (pamh);
|
||||
while (env && *env)
|
||||
{
|
||||
if (putenv (*env) != 0)
|
||||
err (EXIT_FAILURE, NULL);
|
||||
env++;
|
||||
}
|
||||
}
|
||||
|
||||
static void
|
||||
create_watching_parent (void)
|
||||
{
|
||||
pid_t child;
|
||||
sigset_t ourset;
|
||||
int status = 0;
|
||||
int retval;
|
||||
|
||||
retval = pam_open_session (pamh, 0);
|
||||
if (is_pam_failure(retval))
|
||||
{
|
||||
cleanup_pam (retval);
|
||||
errx (EXIT_FAILURE, _("cannot not open session: %s"),
|
||||
pam_strerror (pamh, retval));
|
||||
}
|
||||
else
|
||||
_pam_session_opened = 1;
|
||||
|
||||
child = fork ();
|
||||
if (child == (pid_t) -1)
|
||||
{
|
||||
cleanup_pam (PAM_ABORT);
|
||||
err (EXIT_FAILURE, _("cannot create child process"));
|
||||
}
|
||||
|
||||
/* the child proceeds to run the shell */
|
||||
if (child == 0)
|
||||
return;
|
||||
|
||||
/* In the parent watch the child. */
|
||||
|
||||
/* su without pam support does not have a helper that keeps
|
||||
sitting on any directory so let's go to /. */
|
||||
if (chdir ("/") != 0)
|
||||
warn (_("cannot change directory to %s"), "/");
|
||||
|
||||
sigfillset (&ourset);
|
||||
if (sigprocmask (SIG_BLOCK, &ourset, NULL))
|
||||
{
|
||||
warn (_("cannot block signals"));
|
||||
caught_signal = true;
|
||||
}
|
||||
if (!caught_signal)
|
||||
{
|
||||
struct sigaction action;
|
||||
action.sa_handler = su_catch_sig;
|
||||
sigemptyset (&action.sa_mask);
|
||||
action.sa_flags = 0;
|
||||
sigemptyset (&ourset);
|
||||
if (!same_session)
|
||||
{
|
||||
if (sigaddset(&ourset, SIGINT) || sigaddset(&ourset, SIGQUIT))
|
||||
{
|
||||
warn (_("cannot set signal handler"));
|
||||
caught_signal = true;
|
||||
}
|
||||
}
|
||||
if (!caught_signal && (sigaddset(&ourset, SIGTERM)
|
||||
|| sigaddset(&ourset, SIGALRM)
|
||||
|| sigaction(SIGTERM, &action, NULL)
|
||||
|| sigprocmask(SIG_UNBLOCK, &ourset, NULL))) {
|
||||
warn (_("cannot set signal handler"));
|
||||
caught_signal = true;
|
||||
}
|
||||
if (!caught_signal && !same_session && (sigaction(SIGINT, &action, NULL)
|
||||
|| sigaction(SIGQUIT, &action, NULL)))
|
||||
{
|
||||
warn (_("cannot set signal handler"));
|
||||
caught_signal = true;
|
||||
}
|
||||
}
|
||||
if (!caught_signal)
|
||||
{
|
||||
pid_t pid;
|
||||
for (;;)
|
||||
{
|
||||
pid = waitpid (child, &status, WUNTRACED);
|
||||
|
||||
if (pid != (pid_t)-1 && WIFSTOPPED (status))
|
||||
{
|
||||
kill (getpid (), SIGSTOP);
|
||||
/* once we get here, we must have resumed */
|
||||
kill (pid, SIGCONT);
|
||||
}
|
||||
else
|
||||
break;
|
||||
}
|
||||
if (pid != (pid_t)-1)
|
||||
if (WIFSIGNALED (status))
|
||||
status = WTERMSIG (status) + 128;
|
||||
else
|
||||
status = WEXITSTATUS (status);
|
||||
else
|
||||
status = 1;
|
||||
}
|
||||
else
|
||||
status = 1;
|
||||
|
||||
if (caught_signal)
|
||||
{
|
||||
fprintf (stderr, _("\nSession terminated, killing shell..."));
|
||||
kill (child, SIGTERM);
|
||||
}
|
||||
|
||||
cleanup_pam (PAM_SUCCESS);
|
||||
|
||||
if (caught_signal)
|
||||
{
|
||||
sleep (2);
|
||||
kill (child, SIGKILL);
|
||||
fprintf (stderr, _(" ...killed.\n"));
|
||||
}
|
||||
exit (status);
|
||||
}
|
||||
|
||||
static void
|
||||
authenticate (const struct passwd *pw)
|
||||
{
|
||||
const struct passwd *lpw;
|
||||
const char *cp;
|
||||
int retval;
|
||||
|
||||
retval = pam_start (simulate_login ? PAM_SERVICE_NAME_L : PAM_SERVICE_NAME,
|
||||
pw->pw_name, &conv, &pamh);
|
||||
if (is_pam_failure(retval))
|
||||
goto done;
|
||||
|
||||
if (isatty (0) && (cp = ttyname (0)) != NULL)
|
||||
{
|
||||
const char *tty;
|
||||
|
||||
if (strncmp (cp, "/dev/", 5) == 0)
|
||||
tty = cp + 5;
|
||||
else
|
||||
tty = cp;
|
||||
retval = pam_set_item (pamh, PAM_TTY, tty);
|
||||
if (is_pam_failure(retval))
|
||||
goto done;
|
||||
}
|
||||
|
||||
lpw = getpwuid (getuid ());
|
||||
if (lpw && lpw->pw_name)
|
||||
{
|
||||
retval = pam_set_item (pamh, PAM_RUSER, (const void *) lpw->pw_name);
|
||||
if (is_pam_failure(retval))
|
||||
goto done;
|
||||
}
|
||||
|
||||
retval = pam_authenticate (pamh, 0);
|
||||
if (is_pam_failure(retval))
|
||||
goto done;
|
||||
|
||||
retval = pam_acct_mgmt (pamh, 0);
|
||||
if (retval == PAM_NEW_AUTHTOK_REQD)
|
||||
{
|
||||
/* Password has expired. Offer option to change it. */
|
||||
retval = pam_chauthtok (pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
|
||||
}
|
||||
|
||||
done:
|
||||
|
||||
log_su (pw, !is_pam_failure(retval));
|
||||
|
||||
if (is_pam_failure(retval))
|
||||
{
|
||||
const char *msg = pam_strerror(pamh, retval);
|
||||
pam_end(pamh, retval);
|
||||
sleep (getlogindefs_num ("FAIL_DELAY", 1));
|
||||
errx (EXIT_FAILURE, "%s", msg?msg:_("incorrect password"));
|
||||
}
|
||||
}
|
||||
|
||||
/* Add or clear /sbin and /usr/sbin for the su command
|
||||
used without `-'. */
|
||||
|
||||
/* Set if /sbin is found in path. */
|
||||
#define SBIN_MASK 0x01
|
||||
/* Set if /usr/sbin is found in path. */
|
||||
#define USBIN_MASK 0x02
|
||||
|
||||
static char *
|
||||
addsbin (const char *const path)
|
||||
{
|
||||
unsigned char smask = 0;
|
||||
char *ptr, *tmp, *cur, *ret = NULL;
|
||||
size_t len;
|
||||
|
||||
if (!path || *path == 0)
|
||||
return NULL;
|
||||
|
||||
tmp = xstrdup (path);
|
||||
cur = tmp;
|
||||
for (ptr = strsep (&cur, ":"); ptr != NULL; ptr = strsep (&cur, ":"))
|
||||
{
|
||||
if (!strcmp (ptr, "/sbin"))
|
||||
smask |= SBIN_MASK;
|
||||
if (!strcmp (ptr, "/usr/sbin"))
|
||||
smask |= USBIN_MASK;
|
||||
}
|
||||
|
||||
if ((smask & (USBIN_MASK|SBIN_MASK)) == (USBIN_MASK|SBIN_MASK))
|
||||
{
|
||||
free (tmp);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
len = strlen (path);
|
||||
if (!(smask & USBIN_MASK))
|
||||
len += strlen ("/usr/sbin:");
|
||||
|
||||
if (!(smask & SBIN_MASK))
|
||||
len += strlen (":/sbin");
|
||||
|
||||
ret = xmalloc (len + 1);
|
||||
strcpy (tmp, path);
|
||||
|
||||
*ret = 0;
|
||||
cur = tmp;
|
||||
for (ptr = strsep (&cur, ":"); ptr; ptr = strsep (&cur, ":"))
|
||||
{
|
||||
if (!strcmp (ptr, "."))
|
||||
continue;
|
||||
if (*ret)
|
||||
strcat (ret, ":");
|
||||
if (!(smask & USBIN_MASK) && !strcmp (ptr, "/bin"))
|
||||
{
|
||||
strcat (ret, "/usr/sbin:");
|
||||
strcat (ret, ptr);
|
||||
smask |= USBIN_MASK;
|
||||
continue;
|
||||
}
|
||||
if (!(smask & SBIN_MASK) && !strcmp (ptr, "/usr/bin"))
|
||||
{
|
||||
strcat (ret, ptr);
|
||||
strcat (ret, ":/sbin");
|
||||
smask |= SBIN_MASK;
|
||||
continue;
|
||||
}
|
||||
strcat (ret, ptr);
|
||||
}
|
||||
free (tmp);
|
||||
|
||||
if (!(smask & USBIN_MASK))
|
||||
strcat (ret, ":/usr/sbin");
|
||||
|
||||
if (!(smask & SBIN_MASK))
|
||||
strcat (ret, ":/sbin");
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static char *
|
||||
clearsbin (const char *const path)
|
||||
{
|
||||
char *ptr, *tmp, *cur, *ret = NULL;
|
||||
|
||||
if (!path || *path == 0)
|
||||
return NULL;
|
||||
|
||||
tmp = xstrdup (path);
|
||||
|
||||
ret = xmalloc (strlen (path) + 1);
|
||||
*ret = 0;
|
||||
cur = tmp;
|
||||
for (ptr = strsep (&cur, ":"); ptr; ptr = strsep (&cur, ":"))
|
||||
{
|
||||
if (!strcmp (ptr, "/sbin"))
|
||||
continue;
|
||||
if (!strcmp (ptr, "/usr/sbin"))
|
||||
continue;
|
||||
if (!strcmp (ptr, "/usr/local/sbin"))
|
||||
continue;
|
||||
if (*ret)
|
||||
strcat (ret, ":");
|
||||
strcat (ret, ptr);
|
||||
}
|
||||
free (tmp);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void
|
||||
set_path(const struct passwd* pw)
|
||||
{
|
||||
int r;
|
||||
if (pw->pw_uid)
|
||||
r = logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH);
|
||||
|
||||
else if ((r = logindefs_setenv("PATH", "ENV_ROOTPATH", NULL)) != 0)
|
||||
r = logindefs_setenv("PATH", "ENV_SUPATH", _PATH_DEFPATH_ROOT);
|
||||
|
||||
if (r != 0)
|
||||
err (EXIT_FAILURE, _("failed to set PATH"));
|
||||
}
|
||||
|
||||
/* 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)
|
||||
{
|
||||
if (simulate_login)
|
||||
{
|
||||
/* Leave TERM unchanged. Set HOME, SHELL, USER, LOGNAME, PATH.
|
||||
Unset all other environment variables. */
|
||||
char const *term = getenv ("TERM");
|
||||
if (term)
|
||||
term = xstrdup (term);
|
||||
environ = xmalloc ((6 + !!term) * sizeof (char *));
|
||||
environ[0] = NULL;
|
||||
if (term)
|
||||
xsetenv ("TERM", term, 1);
|
||||
xsetenv ("HOME", pw->pw_dir, 1);
|
||||
xsetenv ("SHELL", shell, 1);
|
||||
xsetenv ("USER", pw->pw_name, 1);
|
||||
xsetenv ("LOGNAME", pw->pw_name, 1);
|
||||
set_path(pw);
|
||||
}
|
||||
else
|
||||
{
|
||||
/* Set HOME, SHELL, and if not becoming a super-user,
|
||||
USER and LOGNAME. */
|
||||
if (change_environment)
|
||||
{
|
||||
xsetenv ("HOME", pw->pw_dir, 1);
|
||||
xsetenv ("SHELL", shell, 1);
|
||||
if (getlogindefs_bool ("ALWAYS_SET_PATH", 0))
|
||||
set_path(pw);
|
||||
else
|
||||
{
|
||||
char const *path = getenv ("PATH");
|
||||
char *new = NULL;
|
||||
|
||||
if (pw->pw_uid)
|
||||
new = clearsbin (path);
|
||||
else
|
||||
new = addsbin (path);
|
||||
|
||||
if (new)
|
||||
{
|
||||
xsetenv ("PATH", new, 1);
|
||||
free (new);
|
||||
}
|
||||
}
|
||||
if (pw->pw_uid)
|
||||
{
|
||||
xsetenv ("USER", pw->pw_name, 1);
|
||||
xsetenv ("LOGNAME", pw->pw_name, 1);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
export_pamenv ();
|
||||
}
|
||||
|
||||
/* Become the user and group(s) specified by PW. */
|
||||
|
||||
static void
|
||||
init_groups (const struct passwd *pw, gid_t *groups, int num_groups)
|
||||
{
|
||||
int retval;
|
||||
|
||||
errno = 0;
|
||||
|
||||
if (num_groups)
|
||||
retval = setgroups (num_groups, groups);
|
||||
else
|
||||
retval = initgroups (pw->pw_name, pw->pw_gid);
|
||||
|
||||
if (retval == -1)
|
||||
{
|
||||
cleanup_pam (PAM_ABORT);
|
||||
err (EXIT_FAILURE, _("cannot set groups"));
|
||||
}
|
||||
endgrent ();
|
||||
|
||||
retval = pam_setcred (pamh, PAM_ESTABLISH_CRED);
|
||||
if (is_pam_failure(retval))
|
||||
errx (EXIT_FAILURE, "%s", pam_strerror (pamh, retval));
|
||||
else
|
||||
_pam_cred_established = 1;
|
||||
}
|
||||
|
||||
static void
|
||||
change_identity (const struct passwd *pw)
|
||||
{
|
||||
if (setgid (pw->pw_gid))
|
||||
err (EXIT_FAILURE, _("cannot set group id"));
|
||||
if (setuid (pw->pw_uid))
|
||||
err (EXIT_FAILURE, _("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.
|
||||
Pass ADDITIONAL_ARGS to the shell as more arguments; there
|
||||
are N_ADDITIONAL_ARGS extra arguments. */
|
||||
|
||||
static void
|
||||
run_shell (char const *shell, char const *command, char **additional_args,
|
||||
size_t n_additional_args)
|
||||
{
|
||||
size_t n_args = 1 + fast_startup + 2 * !!command + n_additional_args + 1;
|
||||
char const **args = xcalloc (n_args, sizeof *args);
|
||||
size_t argno = 1;
|
||||
|
||||
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;
|
||||
}
|
||||
memcpy (args + argno, additional_args, n_additional_args * sizeof *args);
|
||||
args[argno + n_additional_args] = NULL;
|
||||
execv (shell, (char **) args);
|
||||
|
||||
{
|
||||
int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
|
||||
warn ("%s", shell);
|
||||
exit (exit_status);
|
||||
}
|
||||
}
|
||||
|
||||
/* Return true if SHELL is a restricted shell (one not returned by
|
||||
getusershell), else false, meaning it is a standard shell. */
|
||||
|
||||
static bool
|
||||
restricted_shell (const char *shell)
|
||||
{
|
||||
char *line;
|
||||
|
||||
setusershell ();
|
||||
while ((line = getusershell ()) != NULL)
|
||||
{
|
||||
if (*line != '#' && !strcmp (line, shell))
|
||||
{
|
||||
endusershell ();
|
||||
return false;
|
||||
}
|
||||
}
|
||||
endusershell ();
|
||||
return true;
|
||||
}
|
||||
|
||||
static void __attribute__((__noreturn__))
|
||||
usage (int status)
|
||||
{
|
||||
if (status != EXIT_SUCCESS)
|
||||
fprintf (stderr, _("Try `%s --help' for more information.\n"),
|
||||
program_invocation_short_name);
|
||||
else
|
||||
{
|
||||
fputs(USAGE_HEADER, stdout);
|
||||
printf (_(" %s [options] [-] [USER [arg]...]\n"), program_invocation_short_name);
|
||||
fputs (_("\n\
|
||||
Change the effective user id and group id to that of USER.\n\
|
||||
A mere - implies -l. If USER not given, assume root.\n"), stdout);
|
||||
fputs(USAGE_OPTIONS, stdout);
|
||||
fputs (_("\
|
||||
-, -l, --login make the shell a login shell\n\
|
||||
-c, --command <command> pass a single command to the shell with -c\n\
|
||||
--session-command <command> pass a single command to the shell with -c\n\
|
||||
and do not create a new session\n\
|
||||
-g --group=group specify the primary group\n\
|
||||
-G --supp-group=group specify a supplemental group\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\
|
||||
"), stdout);
|
||||
|
||||
fputs(USAGE_SEPARATOR, stdout);
|
||||
fputs(USAGE_HELP, stdout);
|
||||
fputs(USAGE_VERSION, stdout);
|
||||
printf(USAGE_MAN_TAIL("su(1)"));
|
||||
}
|
||||
exit (status);
|
||||
}
|
||||
|
||||
static
|
||||
void load_config(void)
|
||||
{
|
||||
logindefs_load_file("/etc/default/su");
|
||||
logindefs_load_file(_PATH_LOGINDEFS);
|
||||
}
|
||||
|
||||
/*
|
||||
* Returns 1 if the current user is not root
|
||||
*/
|
||||
static int
|
||||
evaluate_uid(void)
|
||||
{
|
||||
uid_t ruid = getuid();
|
||||
uid_t euid = geteuid();
|
||||
|
||||
/* if we're really root and aren't running setuid */
|
||||
return (uid_t) 0 == ruid && ruid == euid ? 0 : 1;
|
||||
}
|
||||
|
||||
int
|
||||
main (int argc, char **argv)
|
||||
{
|
||||
int optc;
|
||||
const char *new_user = DEFAULT_USER;
|
||||
char *command = NULL;
|
||||
int request_same_session = 0;
|
||||
char *shell = NULL;
|
||||
struct passwd *pw;
|
||||
struct passwd pw_copy;
|
||||
struct group *gr;
|
||||
gid_t groups[NGROUPS_MAX];
|
||||
int num_supp_groups = 0;
|
||||
int use_gid = 0;
|
||||
int restricted;
|
||||
|
||||
setlocale (LC_ALL, "");
|
||||
bindtextdomain (PACKAGE, LOCALEDIR);
|
||||
textdomain (PACKAGE);
|
||||
|
||||
fast_startup = false;
|
||||
simulate_login = false;
|
||||
change_environment = true;
|
||||
|
||||
while ((optc = getopt_long (argc, argv, "c:fg:G:lmps:hV", longopts, NULL)) != -1)
|
||||
{
|
||||
switch (optc)
|
||||
{
|
||||
case 'c':
|
||||
command = optarg;
|
||||
break;
|
||||
|
||||
case 'C':
|
||||
command = optarg;
|
||||
request_same_session = 1;
|
||||
break;
|
||||
|
||||
case 'f':
|
||||
fast_startup = true;
|
||||
break;
|
||||
|
||||
case 'g':
|
||||
gr = getgrnam(optarg);
|
||||
if (!gr)
|
||||
errx(EXIT_FAILURE, _("group %s does not exist"), optarg);
|
||||
use_gid = 1;
|
||||
groups[0] = gr->gr_gid;
|
||||
break;
|
||||
|
||||
case 'G':
|
||||
num_supp_groups++;
|
||||
if (num_supp_groups >= NGROUPS_MAX)
|
||||
errx(EXIT_FAILURE,
|
||||
_("can't specify more than %d supplemental groups"),
|
||||
NGROUPS_MAX - 1);
|
||||
gr = getgrnam(optarg);
|
||||
if (!gr)
|
||||
errx(EXIT_FAILURE, _("group %s does not exist"), optarg);
|
||||
groups[num_supp_groups] = gr->gr_gid;
|
||||
break;
|
||||
|
||||
case 'l':
|
||||
simulate_login = true;
|
||||
break;
|
||||
|
||||
case 'm':
|
||||
case 'p':
|
||||
change_environment = false;
|
||||
break;
|
||||
|
||||
case 's':
|
||||
shell = optarg;
|
||||
break;
|
||||
|
||||
case 'h':
|
||||
usage(0);
|
||||
|
||||
case 'V':
|
||||
printf(UTIL_LINUX_VERSION);
|
||||
exit(EXIT_SUCCESS);
|
||||
|
||||
default:
|
||||
usage (EXIT_FAILURE);
|
||||
}
|
||||
}
|
||||
|
||||
restricted = evaluate_uid ();
|
||||
|
||||
if (optind < argc && !strcmp (argv[optind], "-"))
|
||||
{
|
||||
simulate_login = true;
|
||||
++optind;
|
||||
}
|
||||
if (optind < argc)
|
||||
new_user = argv[optind++];
|
||||
|
||||
if ((num_supp_groups || use_gid) && restricted)
|
||||
errx(EXIT_FAILURE, _("only root can specify alternative groups"));
|
||||
|
||||
logindefs_load_defaults = load_config;
|
||||
|
||||
pw = getpwnam (new_user);
|
||||
if (! (pw && pw->pw_name && pw->pw_name[0] && pw->pw_dir && pw->pw_dir[0]
|
||||
&& pw->pw_passwd))
|
||||
errx (EXIT_FAILURE, _("user %s does not exist"), new_user);
|
||||
|
||||
/* 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.
|
||||
Also, make sure pw->pw_shell is a nonempty string.
|
||||
It may be NULL when NEW_USER is a username that is retrieved via NIS (YP),
|
||||
but that doesn't have a default shell listed. */
|
||||
pw_copy = *pw;
|
||||
pw = &pw_copy;
|
||||
pw->pw_name = xstrdup (pw->pw_name);
|
||||
pw->pw_passwd = xstrdup (pw->pw_passwd);
|
||||
pw->pw_dir = xstrdup (pw->pw_dir);
|
||||
pw->pw_shell = xstrdup (pw->pw_shell && pw->pw_shell[0]
|
||||
? pw->pw_shell
|
||||
: DEFAULT_SHELL);
|
||||
endpwent ();
|
||||
|
||||
if (num_supp_groups && !use_gid)
|
||||
{
|
||||
pw->pw_gid = groups[1];
|
||||
memmove (groups, groups + 1, sizeof(gid_t) * num_supp_groups);
|
||||
}
|
||||
else if (use_gid)
|
||||
{
|
||||
pw->pw_gid = groups[0];
|
||||
num_supp_groups++;
|
||||
}
|
||||
|
||||
authenticate (pw);
|
||||
|
||||
if (request_same_session || !command || !pw->pw_uid)
|
||||
same_session = 1;
|
||||
|
||||
if (!shell && !change_environment)
|
||||
shell = getenv ("SHELL");
|
||||
if (shell && getuid () != 0 && 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. */
|
||||
warnx (_("using restricted shell %s"), pw->pw_shell);
|
||||
shell = NULL;
|
||||
}
|
||||
shell = xstrdup (shell ? shell : pw->pw_shell);
|
||||
|
||||
init_groups (pw, groups, num_supp_groups);
|
||||
|
||||
create_watching_parent ();
|
||||
/* Now we're in the child. */
|
||||
|
||||
change_identity (pw);
|
||||
if (!same_session)
|
||||
setsid ();
|
||||
|
||||
/* Set environment after pam_open_session, which may put KRB5CCNAME
|
||||
into the pam_env, etc. */
|
||||
|
||||
modify_environment (pw, shell);
|
||||
|
||||
if (simulate_login && chdir (pw->pw_dir) != 0)
|
||||
warn (_("warning: cannot change directory to %s"), pw->pw_dir);
|
||||
|
||||
run_shell (shell, command, argv + optind, max (0, argc - optind));
|
||||
}
|
||||
|
||||
// vim: sw=2 cinoptions=>4,n-2,{2,^-2,\:2,=2,g0,h2,p5,t0,+2,(0,u0,w1,m1
|
||||
|
|
Loading…
Reference in New Issue