-/* 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.
-
- 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 implementation by David MacKenzie <djm@gnu.ai.mit.edu>. */
-
-enum
-{
- EXIT_CANNOT_INVOKE = 126,
- EXIT_ENOENT = 127
-};
-
-#include <config.h>
+/*
+ * su(1) 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
+ * Copyright (C) 2016-2017 Karel Zak <kzak@redhat.com>
+ *
+ * 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.
+ *
+ * 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.
+ *
+ *
+ * Based on an implementation by David MacKenzie <djm@gnu.ai.mit.edu>.
+ */
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#include <syslog.h>
#include <utmpx.h>
+#if defined(HAVE_LIBUTIL) && defined(HAVE_PTY_H) && defined(HAVE_SYS_SIGNALFD_H)
+# include <pty.h>
+# include <poll.h>
+# include <sys/signalfd.h>
+# include "all-io.h"
+# define USE_PTY
+#endif
+
#include "err.h"
#include <stdbool.h>
+
#include "c.h"
#include "xalloc.h"
#include "nls.h"
#include "pathnames.h"
#include "env.h"
#include "closestream.h"
+#include "strv.h"
#include "strutils.h"
#include "ttyutils.h"
+#include "pwdutils.h"
+#include "optutils.h"
+
+#include "logindefs.h"
+#include "su-common.h"
+
+#include "debug.h"
+
+UL_DEBUG_DEFINE_MASK(su);
+UL_DEBUG_DEFINE_MASKNAMES(su) = UL_DEBUG_EMPTY_MASKNAMES;
+
+#define SU_DEBUG_INIT (1 << 1)
+#define SU_DEBUG_PAM (1 << 2)
+#define SU_DEBUG_PARENT (1 << 3)
+#define SU_DEBUG_TTY (1 << 4)
+#define SU_DEBUG_LOG (1 << 5)
+#define SU_DEBUG_MISC (1 << 6)
+#define SU_DEBUG_SIG (1 << 7)
+#define SU_DEBUG_PTY (1 << 8)
+#define SU_DEBUG_ALL 0xFFFF
+
+#define DBG(m, x) __UL_DBG(su, SU_DEBUG_, m, x)
+#define ON_DBG(m, x) __UL_DBG_CALL(su, SU_DEBUG_, m, x)
+
/* name of the pam configuration files. separate configs for su and su - */
#define PAM_SRVNAME_SU "su"
#define is_pam_failure(_rc) ((_rc) != PAM_SUCCESS)
-#include "logindefs.h"
-#include "su-common.h"
-
/* The shell to run if none is given in the user's passwd entry. */
#define DEFAULT_SHELL "/bin/sh"
extern char **environ;
#endif
-static void run_shell (char const *, char const *, char **, size_t)
- __attribute__ ((__noreturn__));
+enum {
+ SIGTERM_IDX = 0,
+ SIGINT_IDX,
+ SIGQUIT_IDX,
+
+ SIGNALS_IDX_COUNT
+};
+
+/*
+ * su/runuser control struct
+ */
+struct su_context {
+ pam_handle_t *pamh; /* PAM handler */
+ struct pam_conv conv; /* PAM conversation */
+
+ struct passwd *pwd; /* new user info */
+ char *pwdbuf; /* pwd strings */
+
+ const char *tty_name; /* tty_path without /dev prefix */
+ const char *tty_number; /* end of the tty_path */
-/* If true, pass the `-f' option to the subshell. */
-static bool fast_startup;
+ char *new_user; /* wanted user */
+ char *old_user; /* original user */
-/* If true, simulate a login instead of just starting a shell. */
-static bool simulate_login;
+ pid_t child; /* fork() baby */
+ int childstatus; /* wait() status */
-/* If true, change some environment vars to indicate the user su'd to. */
-static bool change_environment;
+ char **env_whitelist_names; /* environment whitelist */
+ char **env_whitelist_vals;
-/* If true, then don't call setsid() with a command. */
-static int same_session = 0;
+ struct sigaction oldact[SIGNALS_IDX_COUNT]; /* original sigactions indexed by SIG*_IDX */
-/* SU_MODE_{RUNUSER,SU} */
-static int su_mode;
+#ifdef USE_PTY
+ struct termios stdin_attrs; /* stdin and slave terminal runtime attributes */
+ int pty_master;
+ int pty_slave;
+ int pty_sigfd; /* signalfd() */
+ int poll_timeout;
+ struct winsize win; /* terminal window size */
+ sigset_t oldsig; /* original signal mask */
+#endif
+ unsigned int runuser :1, /* flase=su, true=runuser */
+ runuser_uopt :1, /* runuser -u specified */
+ isterm :1, /* is stdin terminal? */
+ fast_startup :1, /* pass the `-f' option to the subshell. */
+ simulate_login :1, /* simulate a login instead of just starting a shell. */
+ change_environment :1, /* change some environment vars to indicate the user su'd to.*/
+ same_session :1, /* don't call setsid() with a command. */
+ suppress_pam_info:1, /* don't print PAM info messages (Last login, etc.). */
+ pam_has_session :1, /* PAM session opened */
+ pam_has_cred :1, /* PAM cred established */
+ pty :1, /* create pseudo-terminal */
+ restricted :1; /* false for root user */
+};
-/* Don't print PAM info messages (Last login, etc.). */
-static int suppress_pam_info;
-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 int restricted = 1; /* zero for root user */
+/* Signal handler for parent process. */
+static void
+su_catch_sig(int sig)
+{
+ caught_signal = sig;
+}
+
+static void su_init_debug(void)
+{
+ __UL_INIT_DEBUG_FROM_ENV(su, SU_DEBUG_, 0, SU_DEBUG);
+}
+
+static void init_tty(struct su_context *su)
+{
+ su->isterm = isatty(STDIN_FILENO) ? 1 : 0;
+ DBG(TTY, ul_debug("initialize [is-term=%s]", su->isterm ? "true" : "false"));
+ if (su->isterm)
+ get_terminal_name(NULL, &su->tty_name, &su->tty_number);
+}
+
+/*
+ * Note, this function has to be possible call more than once. If the child is
+ * already dead than it returns saved result from the previous call.
+ */
+static int wait_for_child(struct su_context *su)
+{
+ pid_t pid = (pid_t) -1;;
+ int status = 0;
+
+ if (su->child == (pid_t) -1)
+ return su->childstatus;
+
+ if (su->child != (pid_t) -1) {
+ /*
+ * The "su" parent process spends all time here in waitpid(),
+ * but "su --pty" uses pty_proxy_master() and waitpid() is only
+ * called to pick up child status or to react to SIGSTOP.
+ */
+ DBG(SIG, ul_debug("waiting for child [%d]...", su->child));
+ for (;;) {
+ pid = waitpid(su->child, &status, WUNTRACED);
+
+ if (pid != (pid_t) - 1 && WIFSTOPPED(status)) {
+ DBG(SIG, ul_debug(" child got SIGSTOP -- stop all session"));
+ kill(getpid(), SIGSTOP);
+ /* once we get here, we must have resumed */
+ kill(pid, SIGCONT);
+ DBG(SIG, ul_debug(" session resumed -- continue"));
+#ifdef USE_PTY
+ /* Let's go back to pty_proxy_master() */
+ if (su->pty_sigfd != -1) {
+ DBG(SIG, ul_debug(" leaving on child SIGSTOP"));
+ return 0;
+ }
+#endif
+ } else
+ break;
+ }
+ }
+ if (pid != (pid_t) -1) {
+ if (WIFSIGNALED(status)) {
+ fprintf(stderr, "%s%s\n",
+ strsignal(WTERMSIG(status)),
+ WCOREDUMP(status) ? _(" (core dumped)")
+ : "");
+ status = WTERMSIG(status) + 128;
+ } else
+ status = WEXITSTATUS(status);
+
+ DBG(SIG, ul_debug("child %d is dead", su->child));
+ su->child = (pid_t) -1; /* Don't use the PID anymore! */
+ su->childstatus = status;
+ } else if (caught_signal)
+ status = caught_signal + 128;
+ else
+ status = 1;
+
+ DBG(SIG, ul_debug("child status=%d", status));
+ return status;
+}
-static const struct passwd *
-current_getpwuid(void)
+#ifdef USE_PTY
+static void pty_init_slave(struct su_context *su)
{
- uid_t ruid;
+ DBG(PTY, ul_debug("initialize slave"));
+
+ ioctl(su->pty_slave, TIOCSCTTY, 1);
+ close(su->pty_master);
- /* GNU Hurd implementation has an extension where a process can exist in a
- * non-conforming environment, and thus be outside the realms of POSIX
- * process identifiers; on this platform, getuid() fails with a status of
- * (uid_t)(-1) and sets errno if a program is run from a non-conforming
- * environment.
- *
- * http://austingroupbugs.net/view.php?id=511
- */
- errno = 0;
- ruid = getuid ();
+ dup2(su->pty_slave, STDIN_FILENO);
+ dup2(su->pty_slave, STDOUT_FILENO);
+ dup2(su->pty_slave, STDERR_FILENO);
- return errno == 0 ? getpwuid (ruid) : NULL;
+ close(su->pty_slave);
+ close(su->pty_sigfd);
+
+ su->pty_slave = -1;
+ su->pty_master = -1;
+ su->pty_sigfd = -1;
+
+ sigprocmask(SIG_SETMASK, &su->oldsig, NULL);
+
+ DBG(PTY, ul_debug("... initialize slave done"));
}
-/* 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 pty_create(struct su_context *su)
+{
+ struct termios slave_attrs;
+ int rc;
+
+ if (su->isterm) {
+ DBG(PTY, ul_debug("create for terminal"));
+
+ /* original setting of the current terminal */
+ if (tcgetattr(STDIN_FILENO, &su->stdin_attrs) != 0)
+ err(EXIT_FAILURE, _("failed to get terminal attributes"));
+ ioctl(STDIN_FILENO, TIOCGWINSZ, (char *)&su->win);
+ /* create master+slave */
+ rc = openpty(&su->pty_master, &su->pty_slave, NULL, &su->stdin_attrs, &su->win);
+
+ /* set the current terminal to raw mode; pty_cleanup() reverses this change on exit */
+ slave_attrs = su->stdin_attrs;
+ cfmakeraw(&slave_attrs);
+ slave_attrs.c_lflag &= ~ECHO;
+ tcsetattr(STDIN_FILENO, TCSANOW, &slave_attrs);
+ } else {
+ DBG(PTY, ul_debug("create for non-terminal"));
+ rc = openpty(&su->pty_master, &su->pty_slave, NULL, NULL, NULL);
+
+ if (!rc) {
+ tcgetattr(su->pty_slave, &slave_attrs);
+ slave_attrs.c_lflag &= ~ECHO;
+ tcsetattr(su->pty_slave, TCSANOW, &slave_attrs);
+ }
+ }
-static void
-log_syslog(struct passwd const * const pw, const bool successful)
+ if (rc < 0)
+ err(EXIT_FAILURE, _("failed to create pseudo-terminal"));
+
+ DBG(PTY, ul_debug("pty setup done [master=%d, slave=%d]", su->pty_master, su->pty_slave));
+}
+
+static void pty_cleanup(struct su_context *su)
+{
+ struct termios rtt;
+
+ if (su->pty_master == -1 || !su->isterm)
+ return;
+
+ DBG(PTY, ul_debug("cleanup"));
+ rtt = su->stdin_attrs;
+ tcsetattr(STDIN_FILENO, TCSADRAIN, &rtt);
+}
+
+static int write_output(char *obuf, ssize_t bytes)
+{
+ DBG(PTY, ul_debug(" writing output"));
+
+ if (write_all(STDOUT_FILENO, obuf, bytes)) {
+ DBG(PTY, ul_debug(" writing output *failed*"));
+ warn(_("write failed"));
+ return -errno;
+ }
+
+ return 0;
+}
+
+static int write_to_child(struct su_context *su,
+ char *buf, size_t bufsz)
+{
+ return write_all(su->pty_master, buf, bufsz);
+}
+
+/*
+ * The su(1) is usually faster than shell, so it's a good idea to wait until
+ * the previous message has been already read by shell from slave before we
+ * write to master. This is necessary especially for EOF situation when we can
+ * send EOF to master before shell is fully initialized, to workaround this
+ * problem we wait until slave is empty. For example:
+ *
+ * echo "date" | su
+ *
+ * Unfortunately, the child (usually shell) can ignore stdin at all, so we
+ * don't wait forever to avoid dead locks...
+ *
+ * Note that su --pty is primarily designed for interactive sessions as it
+ * maintains master+slave tty stuff within the session. Use pipe to write to
+ * su(1) and assume non-interactive (tee-like) behavior is NOT well
+ * supported.
+ */
+static void write_eof_to_child(struct su_context *su)
+{
+ unsigned int tries = 0;
+ struct pollfd fds[] = {
+ { .fd = su->pty_slave, .events = POLLIN }
+ };
+ char c = DEF_EOF;
+
+ DBG(PTY, ul_debug(" waiting for empty slave"));
+ while (poll(fds, 1, 10) == 1 && tries < 8) {
+ DBG(PTY, ul_debug(" slave is not empty"));
+ xusleep(250000);
+ tries++;
+ }
+ if (tries < 8)
+ DBG(PTY, ul_debug(" slave is empty now"));
+
+ DBG(PTY, ul_debug(" sending EOF to master"));
+ write_to_child(su, &c, sizeof(char));
+}
+
+static int pty_handle_io(struct su_context *su, int fd, int *eof)
+{
+ char buf[BUFSIZ];
+ ssize_t bytes;
+
+ DBG(PTY, ul_debug("%d FD active", fd));
+ *eof = 0;
+
+ /* read from active FD */
+ bytes = read(fd, buf, sizeof(buf));
+ if (bytes < 0) {
+ if (errno == EAGAIN || errno == EINTR)
+ return 0;
+ return -errno;
+ }
+
+ if (bytes == 0) {
+ *eof = 1;
+ return 0;
+ }
+
+ /* from stdin (user) to command */
+ if (fd == STDIN_FILENO) {
+ DBG(PTY, ul_debug(" stdin --> master %zd bytes", bytes));
+
+ if (write_to_child(su, buf, bytes)) {
+ warn(_("write failed"));
+ return -errno;
+ }
+ /* without sync write_output() will write both input &
+ * shell output that looks like double echoing */
+ fdatasync(su->pty_master);
+
+ /* from command (master) to stdout */
+ } else if (fd == su->pty_master) {
+ DBG(PTY, ul_debug(" master --> stdout %zd bytes", bytes));
+ write_output(buf, bytes);
+ }
+
+ return 0;
+}
+
+static int pty_handle_signal(struct su_context *su, int fd)
+{
+ struct signalfd_siginfo info;
+ ssize_t bytes;
+
+ DBG(SIG, ul_debug("signal FD %d active", fd));
+
+ bytes = read(fd, &info, sizeof(info));
+ if (bytes != sizeof(info)) {
+ if (bytes < 0 && (errno == EAGAIN || errno == EINTR))
+ return 0;
+ return -errno;
+ }
+
+ switch (info.ssi_signo) {
+ case SIGCHLD:
+ DBG(SIG, ul_debug(" get signal SIGCHLD"));
+
+ /* The child terminated or stopped. Note that we ignore SIGCONT
+ * here, because stop/cont semantic is handled by wait_for_child() */
+ if (info.ssi_code == CLD_EXITED
+ || info.ssi_code == CLD_KILLED
+ || info.ssi_code == CLD_DUMPED
+ || info.ssi_status == SIGSTOP)
+ wait_for_child(su);
+ /* The child is dead, force poll() timeout. */
+ if (su->child == (pid_t) -1)
+ su->poll_timeout = 10;
+ return 0;
+ case SIGWINCH:
+ DBG(SIG, ul_debug(" get signal SIGWINCH"));
+ if (su->isterm) {
+ ioctl(STDIN_FILENO, TIOCGWINSZ, (char *)&su->win);
+ ioctl(su->pty_slave, TIOCSWINSZ, (char *)&su->win);
+ }
+ break;
+ case SIGTERM:
+ /* fallthrough */
+ case SIGINT:
+ /* fallthrough */
+ case SIGQUIT:
+ DBG(SIG, ul_debug(" get signal SIG{TERM,INT,QUIT}"));
+ caught_signal = info.ssi_signo;
+ /* Child termination is going to generate SIGCHILD (see above) */
+ kill(su->child, SIGTERM);
+ break;
+ default:
+ abort();
+ }
+
+ return 0;
+}
+
+static void pty_proxy_master(struct su_context *su)
{
- const char *new_user, *old_user, *tty;
+ sigset_t ourset;
+ int rc = 0, ret, eof = 0;
+ enum {
+ POLLFD_SIGNAL = 0,
+ POLLFD_MASTER,
+ POLLFD_STDIN
+
+ };
+ struct pollfd pfd[] = {
+ [POLLFD_SIGNAL] = { .fd = -1, .events = POLLIN | POLLERR | POLLHUP },
+ [POLLFD_MASTER] = { .fd = su->pty_master, .events = POLLIN | POLLERR | POLLHUP },
+ [POLLFD_STDIN] = { .fd = STDIN_FILENO, .events = POLLIN | POLLERR | POLLHUP }
+ };
+
+ /* for PTY mode we use signalfd
+ *
+ * TODO: script(1) initializes this FD before fork, good or bad idea?
+ */
+ sigfillset(&ourset);
+ if (sigprocmask(SIG_BLOCK, &ourset, NULL)) {
+ warn(_("cannot block signals"));
+ caught_signal = true;
+ return;
+ }
- 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. */
- const struct passwd *pwd = current_getpwuid();
- old_user = pwd ? pwd->pw_name : "";
- }
+ sigemptyset(&ourset);
+ sigaddset(&ourset, SIGCHLD);
+ sigaddset(&ourset, SIGWINCH);
+ sigaddset(&ourset, SIGALRM);
+ sigaddset(&ourset, SIGTERM);
+ sigaddset(&ourset, SIGINT);
+ sigaddset(&ourset, SIGQUIT);
+
+ if ((su->pty_sigfd = signalfd(-1, &ourset, SFD_CLOEXEC)) < 0) {
+ warn(("cannot create signal file descriptor"));
+ caught_signal = true;
+ return;
+ }
- if (get_terminal_name(NULL, &tty, NULL) != 0 || !tty)
- tty = "none";
+ pfd[POLLFD_SIGNAL].fd = su->pty_sigfd;
+ su->poll_timeout = -1;
+
+ while (!caught_signal) {
+ size_t i;
+ int errsv;
+
+ DBG(PTY, ul_debug("calling poll()"));
+
+ /* wait for input or signal */
+ ret = poll(pfd, ARRAY_SIZE(pfd), su->poll_timeout);
+ errsv = errno;
+ DBG(PTY, ul_debug("poll() rc=%d", ret));
+
+ if (ret < 0) {
+ if (errsv == EAGAIN)
+ continue;
+ warn(_("poll failed"));
+ break;
+ }
+ if (ret == 0) {
+ DBG(PTY, ul_debug("leaving poll() loop [timeout=%d]", su->poll_timeout));
+ break;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(pfd); i++) {
+ rc = 0;
+
+ if (pfd[i].revents == 0)
+ continue;
+
+ DBG(PTY, ul_debug(" active pfd[%s].fd=%d %s %s %s",
+ i == POLLFD_STDIN ? "stdin" :
+ i == POLLFD_MASTER ? "master" :
+ i == POLLFD_SIGNAL ? "signal" : "???",
+ pfd[i].fd,
+ pfd[i].revents & POLLIN ? "POLLIN" : "",
+ pfd[i].revents & POLLHUP ? "POLLHUP" : "",
+ pfd[i].revents & POLLERR ? "POLLERR" : ""));
+ switch (i) {
+ case POLLFD_STDIN:
+ case POLLFD_MASTER:
+ /* data */
+ if (pfd[i].revents & POLLIN)
+ rc = pty_handle_io(su, pfd[i].fd, &eof);
+ /* EOF maybe detected by two ways:
+ * A) poll() return POLLHUP event after close()
+ * B) read() returns 0 (no data) */
+ if ((pfd[i].revents & POLLHUP) || eof) {
+ DBG(PTY, ul_debug(" ignore FD"));
+ pfd[i].fd = -1;
+ if (i == POLLFD_STDIN) {
+ write_eof_to_child(su);
+ DBG(PTY, ul_debug(" ignore STDIN"));
+ }
+ }
+ continue;
+ case POLLFD_SIGNAL:
+ rc = pty_handle_signal(su, pfd[i].fd);
+ break;
+ }
+ if (rc)
+ break;
+ }
+ }
- openlog (program_invocation_short_name, 0 , LOG_AUTH);
- syslog (LOG_NOTICE, "%s(to %s) %s on %s",
- successful ? "" :
- su_mode == RUNUSER_MODE ? "FAILED RUNUSER " : "FAILED SU ",
- new_user, old_user, tty);
- closelog ();
+ close(su->pty_sigfd);
+ su->pty_sigfd = -1;
+ DBG(PTY, ul_debug("poll() done [signal=%d, rc=%d]", caught_signal, rc));
}
+#endif /* USE_PTY */
+
+
+/* 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_syslog(struct su_context *su, bool successful)
+{
+ DBG(LOG, ul_debug("syslog logging"));
+
+ openlog(program_invocation_short_name, 0, LOG_AUTH);
+ syslog(LOG_NOTICE, "%s(to %s) %s on %s",
+ successful ? "" :
+ su->runuser ? "FAILED RUNUSER " : "FAILED SU ",
+ su->new_user, su->old_user ? : "",
+ su->tty_name ? : "none");
+ closelog();
+}
/*
* Log failed login attempts in _PATH_BTMP if that exists.
*/
-static void log_btmp(struct passwd const * const pw)
+static void log_btmp(struct su_context *su)
{
struct utmpx ut;
struct timeval tv;
- const char *tty_name, *tty_num;
- memset(&ut, 0, sizeof(ut));
+ DBG(LOG, ul_debug("btmp logging"));
- strncpy(ut.ut_user,
- pw && pw->pw_name ? pw->pw_name : "(unknown)",
+ memset(&ut, 0, sizeof(ut));
+ str2memcpy(ut.ut_user,
+ su->pwd && su->pwd->pw_name ? su->pwd->pw_name : "(unknown)",
sizeof(ut.ut_user));
- get_terminal_name(NULL, &tty_name, &tty_num);
- if (tty_num)
- xstrncpy(ut.ut_id, tty_num, sizeof(ut.ut_id));
- if (tty_name)
- xstrncpy(ut.ut_line, tty_name, sizeof(ut.ut_line));
+ if (su->tty_number)
+ str2memcpy(ut.ut_id, su->tty_number, sizeof(ut.ut_id));
+ if (su->tty_name)
+ str2memcpy(ut.ut_line, su->tty_name, sizeof(ut.ut_line));
gettimeofday(&tv, NULL);
ut.ut_tv.tv_sec = tv.tv_sec;
updwtmpx(_PATH_BTMP, &ut);
}
-
-static int su_pam_conv(int num_msg, const struct pam_message **msg,
- struct pam_response **resp, void *appdata_ptr)
+static int supam_conv( int num_msg,
+ const struct pam_message **msg,
+ struct pam_response **resp,
+ void *data)
{
- if (suppress_pam_info
+ struct su_context *su = (struct su_context *) data;
+
+ if (su->suppress_pam_info
&& num_msg == 1
- && msg
- && msg[0]->msg_style == PAM_TEXT_INFO)
+ && msg && msg[0]->msg_style == PAM_TEXT_INFO)
return PAM_SUCCESS;
+
#ifdef HAVE_SECURITY_PAM_MISC_H
- return misc_conv(num_msg, msg, resp, appdata_ptr);
+ return misc_conv(num_msg, msg, resp, data);
#elif defined(HAVE_SECURITY_OPENPAM_H)
- return openpam_ttyconv(num_msg, msg, resp, appdata_ptr);
+ return openpam_ttyconv(num_msg, msg, resp, data);
#endif
}
-static struct pam_conv conv =
+static void supam_cleanup(struct su_context *su, int retcode)
{
- su_pam_conv,
- NULL
-};
+ const int errsv = errno;
-static void
-cleanup_pam (const int retcode)
-{
- const int saved_errno = errno;
+ DBG(PAM, ul_debug("cleanup"));
- if (_pam_session_opened)
- pam_close_session (pamh, 0);
+ if (su->pam_has_session)
+ pam_close_session(su->pamh, 0);
+ if (su->pam_has_cred)
+ pam_setcred(su->pamh, PAM_DELETE_CRED | PAM_SILENT);
+ pam_end(su->pamh, retcode);
+ errno = errsv;
+}
+
+
+static void supam_export_environment(struct su_context *su)
+{
+ char **env;
- if (_pam_cred_established)
- pam_setcred (pamh, PAM_DELETE_CRED | PAM_SILENT);
+ DBG(PAM, ul_debug("init environ[]"));
- pam_end(pamh, retcode);
+ /* This is a copy but don't care to free as we exec later anyways. */
+ env = pam_getenvlist(su->pamh);
- errno = saved_errno;
+ while (env && *env) {
+ if (putenv(*env) != 0)
+ err(EXIT_FAILURE, _("failed to modify environment"));
+ env++;
+ }
}
-/* Signal handler for parent process. */
-static void
-su_catch_sig (int sig)
+static void supam_authenticate(struct su_context *su)
{
- caught_signal = sig;
+ const char *srvname = NULL;
+ int rc;
+
+ srvname = su->runuser ?
+ (su->simulate_login ? PAM_SRVNAME_RUNUSER_L : PAM_SRVNAME_RUNUSER) :
+ (su->simulate_login ? PAM_SRVNAME_SU_L : PAM_SRVNAME_SU);
+
+ DBG(PAM, ul_debug("start [name: %s]", srvname));
+
+ rc = pam_start(srvname, su->pwd->pw_name, &su->conv, &su->pamh);
+ if (is_pam_failure(rc))
+ goto done;
+
+ if (su->tty_name) {
+ rc = pam_set_item(su->pamh, PAM_TTY, su->tty_name);
+ if (is_pam_failure(rc))
+ goto done;
+ }
+ if (su->old_user) {
+ rc = pam_set_item(su->pamh, PAM_RUSER, (const void *) su->old_user);
+ if (is_pam_failure(rc))
+ goto done;
+ }
+ if (su->runuser) {
+ /*
+ * This is the only difference between runuser(1) and su(1). The command
+ * runuser(1) does not required authentication, because user is root.
+ */
+ if (su->restricted)
+ errx(EXIT_FAILURE, _("may not be used by non-root users"));
+ return;
+ }
+
+ rc = pam_authenticate(su->pamh, 0);
+ if (is_pam_failure(rc))
+ goto done;
+
+ /* Check password expiration and offer option to change it. */
+ rc = pam_acct_mgmt(su->pamh, 0);
+ if (rc == PAM_NEW_AUTHTOK_REQD)
+ rc = pam_chauthtok(su->pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
+ done:
+ log_syslog(su, !is_pam_failure(rc));
+
+ if (is_pam_failure(rc)) {
+ const char *msg;
+
+ DBG(PAM, ul_debug("authentication failed"));
+ log_btmp(su);
+
+ msg = pam_strerror(su->pamh, rc);
+ pam_end(su->pamh, rc);
+ sleep(getlogindefs_num("FAIL_DELAY", 1));
+ errx(EXIT_FAILURE, "%s", msg ? msg : _("authentication failed"));
+ }
}
-/* Export env variables declared by PAM modules. */
-static void
-export_pamenv (void)
+static void supam_open_session(struct su_context *su)
{
- char **env;
+ int rc;
+
+ DBG(PAM, ul_debug("opening session"));
- /* 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++;
- }
+ rc = pam_open_session(su->pamh, 0);
+ if (is_pam_failure(rc)) {
+ supam_cleanup(su, rc);
+ errx(EXIT_FAILURE, _("cannot open session: %s"),
+ pam_strerror(su->pamh, rc));
+ } else
+ su->pam_has_session = 1;
}
-static void
-create_watching_parent (void)
-{
- pid_t child;
- sigset_t ourset;
- struct sigaction oldact[3];
- int status = 0;
- const int retval = pam_open_session (pamh, 0);
-
- if (is_pam_failure(retval))
- {
- cleanup_pam (retval);
- errx (EXIT_FAILURE, _("cannot open session: %s"),
- pam_strerror (pamh, retval));
- }
- else
- _pam_session_opened = 1;
-
- memset(oldact, 0, sizeof(oldact));
-
- 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, &oldact[0])
- || sigprocmask(SIG_UNBLOCK, &ourset, NULL))) {
- warn (_("cannot set signal handler"));
- caught_signal = true;
- }
- if (!caught_signal && !same_session && (sigaction(SIGINT, &action, &oldact[1])
- || sigaction(SIGQUIT, &action, &oldact[2])))
- {
- 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))
- {
- fprintf (stderr, "%s%s\n", strsignal (WTERMSIG (status)),
- WCOREDUMP (status) ? _(" (core dumped)") : "");
- status = WTERMSIG (status) + 128;
- }
- else
- status = WEXITSTATUS (status);
-
- /* child is gone, don't use the PID anymore */
- child = (pid_t) -1;
- }
- else if (caught_signal)
- status = caught_signal + 128;
- else
- status = 1;
- }
- else
- status = 1;
-
- if (caught_signal && child != (pid_t)-1)
- {
- fprintf (stderr, _("\nSession terminated, killing shell..."));
- kill (child, SIGTERM);
- }
-
- cleanup_pam (PAM_SUCCESS);
-
- if (caught_signal)
- {
- if (child != (pid_t)-1)
- {
- sleep (2);
- kill (child, SIGKILL);
- fprintf (stderr, _(" ...killed.\n"));
- }
-
- /* Let's terminate itself with the received signal.
- *
- * It seems that shells use WIFSIGNALED() rather than our exit status
- * value to detect situations when is necessary to cleanup (reset)
- * terminal settings (kzak -- Jun 2013).
- */
- switch (caught_signal) {
- case SIGTERM:
- sigaction(SIGTERM, &oldact[0], NULL);
- break;
- case SIGINT:
- sigaction(SIGINT, &oldact[1], NULL);
- break;
- case SIGQUIT:
- sigaction(SIGQUIT, &oldact[2], NULL);
- break;
- default:
- /* just in case that signal stuff initialization failed and
- * caught_signal = true */
- caught_signal = SIGKILL;
- break;
- }
- kill(getpid(), caught_signal);
- }
- exit (status);
+static void parent_setup_signals(struct su_context *su)
+{
+ sigset_t ourset;
+
+ /*
+ * Signals setup
+ *
+ * 1) block all signals
+ */
+ DBG(SIG, ul_debug("initialize signals"));
+
+ 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);
+
+ /* 2a) add wanted signals to the mask (for session) */
+ if (!su->same_session
+ && (sigaddset(&ourset, SIGINT)
+ || sigaddset(&ourset, SIGQUIT))) {
+
+ warn(_("cannot initialize signal mask for session"));
+ caught_signal = true;
+ }
+ /* 2b) add wanted generic signals to the mask */
+ if (!caught_signal
+ && (sigaddset(&ourset, SIGTERM)
+ || sigaddset(&ourset, SIGALRM))) {
+
+ warn(_("cannot initialize signal mask"));
+ caught_signal = true;
+ }
+
+ /* 3a) set signal handlers (for session) */
+ if (!caught_signal
+ && !su->same_session
+ && (sigaction(SIGINT, &action, &su->oldact[SIGINT_IDX])
+ || sigaction(SIGQUIT, &action, &su->oldact[SIGQUIT_IDX]))) {
+
+ warn(_("cannot set signal handler for session"));
+ caught_signal = true;
+ }
+
+ /* 3b) set signal handlers */
+ if (!caught_signal
+ && sigaction(SIGTERM, &action, &su->oldact[SIGTERM_IDX])) {
+
+ warn(_("cannot set signal handler"));
+ caught_signal = true;
+ }
+
+ /* 4) unblock wanted signals */
+ if (!caught_signal
+ && sigprocmask(SIG_UNBLOCK, &ourset, NULL)) {
+
+ warn(_("cannot set signal mask"));
+ caught_signal = true;
+ }
+ }
}
-static void
-authenticate (const struct passwd * const pw)
-{
- const struct passwd *lpw = NULL;
- const char *cp, *srvname = NULL;
- int retval;
-
- switch (su_mode) {
- case SU_MODE:
- srvname = simulate_login ? PAM_SRVNAME_SU_L : PAM_SRVNAME_SU;
- break;
- case RUNUSER_MODE:
- srvname = simulate_login ? PAM_SRVNAME_RUNUSER_L : PAM_SRVNAME_RUNUSER;
- break;
- default:
- abort();
- break;
- }
-
- retval = pam_start (srvname, 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 = current_getpwuid ();
- if (lpw && lpw->pw_name)
- {
- retval = pam_set_item (pamh, PAM_RUSER, (const void *) lpw->pw_name);
- if (is_pam_failure(retval))
- goto done;
- }
-
- if (su_mode == RUNUSER_MODE)
- {
- /*
- * This is the only difference between runuser(1) and su(1). The command
- * runuser(1) does not required authentication, because user is root.
- */
- if (restricted)
- errx(EXIT_FAILURE, _("may not be used by non-root users"));
- return;
- }
-
- 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_syslog(pw, !is_pam_failure(retval));
-
- if (is_pam_failure(retval))
- {
- const char *msg;
-
- log_btmp(pw);
-
- msg = pam_strerror(pamh, retval);
- pam_end(pamh, retval);
- sleep (getlogindefs_num ("FAIL_DELAY", 1));
- errx (EXIT_FAILURE, "%s", msg?msg:_("incorrect password"));
- }
+
+static void create_watching_parent(struct su_context *su)
+{
+ int status;
+
+ DBG(MISC, ul_debug("forking..."));
+#ifdef USE_PTY
+ /* no-op, just save original signal mask to oldsig */
+ sigprocmask(SIG_BLOCK, NULL, &su->oldsig);
+
+ if (su->pty)
+ pty_create(su);
+#endif
+ fflush(stdout); /* ??? */
+
+ switch ((int) (su->child = fork())) {
+ case -1: /* error */
+ supam_cleanup(su, PAM_ABORT);
+#ifdef USE_PTY
+ if (su->pty)
+ pty_cleanup(su);
+#endif
+ err(EXIT_FAILURE, _("cannot create child process"));
+ break;
+
+ case 0: /* child */
+ return;
+
+ default: /* parent */
+ DBG(MISC, ul_debug("child [pid=%d]", (int) su->child));
+ break;
+ }
+
+ /* free unnecessary stuff */
+ free_getlogindefs_data();
+
+ /* 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"), "/");
+#ifdef USE_PTY
+ if (su->pty)
+ pty_proxy_master(su);
+ else
+#endif
+ parent_setup_signals(su);
+
+ /*
+ * Wait for child
+ */
+ if (!caught_signal)
+ status = wait_for_child(su);
+ else
+ status = 1;
+
+ DBG(SIG, ul_debug("final child status=%d", status));
+
+ if (caught_signal && su->child != (pid_t)-1) {
+ fprintf(stderr, _("\nSession terminated, killing shell..."));
+ kill(su->child, SIGTERM);
+ }
+
+ supam_cleanup(su, PAM_SUCCESS);
+
+ if (caught_signal) {
+ if (su->child != (pid_t)-1) {
+ DBG(SIG, ul_debug("killing child"));
+ sleep(2);
+ kill(su->child, SIGKILL);
+ fprintf(stderr, _(" ...killed.\n"));
+ }
+
+ /* Let's terminate itself with the received signal.
+ *
+ * It seems that shells use WIFSIGNALED() rather than our exit status
+ * value to detect situations when is necessary to cleanup (reset)
+ * terminal settings (kzak -- Jun 2013).
+ */
+ DBG(SIG, ul_debug("restore signals setting"));
+ switch (caught_signal) {
+ case SIGTERM:
+ sigaction(SIGTERM, &su->oldact[SIGTERM_IDX], NULL);
+ break;
+ case SIGINT:
+ sigaction(SIGINT, &su->oldact[SIGINT_IDX], NULL);
+ break;
+ case SIGQUIT:
+ sigaction(SIGQUIT, &su->oldact[SIGQUIT_IDX], NULL);
+ break;
+ default:
+ /* just in case that signal stuff initialization failed and
+ * caught_signal = true */
+ caught_signal = SIGKILL;
+ break;
+ }
+ DBG(SIG, ul_debug("self-send %d signal", caught_signal));
+ kill(getpid(), caught_signal);
+ }
+
+#ifdef USE_PTY
+ if (su->pty)
+ pty_cleanup(su);
+#endif
+ DBG(MISC, ul_debug("exiting [rc=%d]", status));
+ exit(status);
}
-static void
-set_path(const struct passwd * const pw)
+/* Adds @name from the current environment to the whitelist. If @name is not
+ * set then nothing is added to the whitelist and returns 1.
+ */
+static int env_whitelist_add(struct su_context *su, const char *name)
{
- int r;
- if (pw->pw_uid)
- r = logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH);
+ const char *env = getenv(name);
+
+ if (!env)
+ return 1;
+ if (strv_extend(&su->env_whitelist_names, name))
+ err_oom();
+ if (strv_extend(&su->env_whitelist_vals, env))
+ err_oom();
+ return 0;
+}
- else if ((r = logindefs_setenv("PATH", "ENV_ROOTPATH", NULL)) != 0)
- r = logindefs_setenv("PATH", "ENV_SUPATH", _PATH_DEFPATH_ROOT);
+static int env_whitelist_setenv(struct su_context *su, int overwrite)
+{
+ char **one;
+ size_t i = 0;
+ int rc;
+
+ STRV_FOREACH(one, su->env_whitelist_names) {
+ rc = setenv(*one, su->env_whitelist_vals[i], overwrite);
+ if (rc)
+ return rc;
+ i++;
+ }
- if (r != 0)
- err (EXIT_FAILURE, _("failed to set the %s environment variable"), "PATH");
+ return 0;
}
-/* Update `environ' for the new shell based on PW, with SHELL being
- the value for the SHELL environment variable. */
+/* Creates (add to) whitelist from comma delimited string */
+static int env_whitelist_from_string(struct su_context *su, const char *str)
+{
+ char **all = strv_split(str, ",");
+ char **one;
-static void
-modify_environment (const struct passwd * const pw, const char * const shell)
-{
- if (simulate_login)
- {
- /* Leave TERM unchanged. Set HOME, SHELL, USER, LOGNAME, PATH.
- Unset all other environment variables. */
- char *term = getenv ("TERM");
- if (term)
- term = xstrdup (term);
- environ = xmalloc ((6 + !!term) * sizeof (char *));
- environ[0] = NULL;
- if (term) {
- xsetenv ("TERM", term, 1);
- free(term);
- }
- xsetenv ("HOME", pw->pw_dir, 1);
- if (shell)
- 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 superuser)
- USER and LOGNAME. */
- if (change_environment)
- {
- xsetenv ("HOME", pw->pw_dir, 1);
- if (shell)
- xsetenv ("SHELL", shell, 1);
- if (getlogindefs_bool ("ALWAYS_SET_PATH", 0))
- set_path(pw);
-
- 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. */
+ if (!all) {
+ if (errno == ENOMEM)
+ err_oom();
+ return -EINVAL;
+ }
-static void
-init_groups (const struct passwd * const pw, const gid_t * const groups, const size_t num_groups)
+ STRV_FOREACH(one, all)
+ env_whitelist_add(su, *one);
+ strv_free(all);
+ return 0;
+}
+
+static void setenv_path(const struct passwd *pw)
{
- int retval;
+ int rc;
- errno = 0;
+ DBG(MISC, ul_debug("setting PATH"));
- if (num_groups)
- retval = setgroups (num_groups, groups);
- else
- retval = initgroups (pw->pw_name, pw->pw_gid);
+ if (pw->pw_uid)
+ rc = logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH);
- if (retval == -1)
- {
- cleanup_pam (PAM_ABORT);
- err (EXIT_FAILURE, _("cannot set groups"));
- }
- endgrent ();
+ else if ((rc = logindefs_setenv("PATH", "ENV_SUPATH", NULL)) != 0)
+ rc = logindefs_setenv("PATH", "ENV_ROOTPATH", _PATH_DEFPATH_ROOT);
- 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;
+ if (rc)
+ err(EXIT_FAILURE, _("failed to set the PATH environment variable"));
}
-static void
-change_identity (const struct passwd * const pw)
+static void modify_environment(struct su_context *su, const char *shell)
{
- if (setgid (pw->pw_gid))
- err (EXIT_FAILURE, _("cannot set group id"));
- if (setuid (pw->pw_uid))
- err (EXIT_FAILURE, _("cannot set user id"));
+ const struct passwd *pw = su->pwd;
+
+
+ DBG(MISC, ul_debug("modify environ[]"));
+
+ /* Leave TERM unchanged. Set HOME, SHELL, USER, LOGNAME, PATH.
+ *
+ * Unset all other environment variables, but follow
+ * --whitelist-environment if specified.
+ */
+ if (su->simulate_login) {
+ /* leave TERM unchanged */
+ env_whitelist_add(su, "TERM");
+
+ /* Note that original su(1) has allocated environ[] by malloc
+ * to the number of expected variables. This seems unnecessary
+ * optimization as libc later re-alloc(current_size+2) and for
+ * empty environ[] the curren_size is zero. It seems better to
+ * keep all logic around environment in glibc's hands.
+ * --kzak [Aug 2018]
+ */
+#ifdef HAVE_CLEARENV
+ clearenv();
+#else
+ environ = NULL;
+#endif
+ /* always reset */
+ if (shell)
+ xsetenv("SHELL", shell, 1);
+
+ setenv_path(pw);
+
+ xsetenv("HOME", pw->pw_dir, 1);
+ xsetenv("USER", pw->pw_name, 1);
+ xsetenv("LOGNAME", pw->pw_name, 1);
+
+ /* apply all from whitelist, but no overwrite */
+ env_whitelist_setenv(su, 0);
+
+ /* Set HOME, SHELL, and (if not becoming a superuser) USER and LOGNAME.
+ */
+ } else if (su->change_environment) {
+ xsetenv("HOME", pw->pw_dir, 1);
+ if (shell)
+ xsetenv("SHELL", shell, 1);
+
+ if (getlogindefs_bool("ALWAYS_SET_PATH", 0))
+ setenv_path(pw);
+
+ if (pw->pw_uid) {
+ xsetenv("USER", pw->pw_name, 1);
+ xsetenv("LOGNAME", pw->pw_name, 1);
+ }
+ }
+
+ supam_export_environment(su);
}
-/* 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 init_groups(struct su_context *su, gid_t *groups, size_t ngroups)
+{
+ int rc;
-static void
-run_shell (char const * const shell, char const * const command, char ** const additional_args,
- const size_t n_additional_args)
-{
- const size_t n_args = 1 + fast_startup + 2 * !!command + n_additional_args + 1;
- const char **args = xcalloc (n_args, sizeof *args);
- size_t argno = 1;
-
- if (simulate_login)
- {
- char *arg0;
- const 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 (_("failed to execute %s"), shell);
- exit (exit_status);
- }
+ DBG(MISC, ul_debug("initialize groups"));
+
+ errno = 0;
+ if (ngroups)
+ rc = setgroups(ngroups, groups);
+ else
+ rc = initgroups(su->pwd->pw_name, su->pwd->pw_gid);
+
+ if (rc == -1) {
+ supam_cleanup(su, PAM_ABORT);
+ err(EXIT_FAILURE, _("cannot set groups"));
+ }
+ endgrent();
+
+ rc = pam_setcred(su->pamh, PAM_ESTABLISH_CRED);
+ if (is_pam_failure(rc))
+ errx(EXIT_FAILURE, _("failed to user credentials: %s"),
+ pam_strerror(su->pamh, rc));
+ su->pam_has_cred = 1;
}
-/* Return true if SHELL is a restricted shell (one not returned by
- getusershell), else false, meaning it is a standard shell. */
+static void change_identity(const struct passwd *pw)
+{
+ DBG(MISC, ul_debug("changing identity [GID=%d, UID=%d]", pw->pw_gid, pw->pw_uid));
+
+ if (setgid(pw->pw_gid))
+ err(EXIT_FAILURE, _("cannot set group id"));
+ if (setuid(pw->pw_uid))
+ err(EXIT_FAILURE, _("cannot set user id"));
+}
-static bool
-restricted_shell (const char * const shell)
+/* Run SHELL, 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(
+ struct su_context *su,
+ char const *shell, char const *command, char **additional_args,
+ size_t n_additional_args)
{
- char *line;
+ size_t n_args = 1 + su->fast_startup + 2 * ! !command + n_additional_args + 1;
+ const char **args = xcalloc(n_args, sizeof *args);
+ size_t argno = 1;
+
+ DBG(MISC, ul_debug("starting shell [shell=%s, command=\"%s\"%s%s]",
+ shell, command,
+ su->simulate_login ? " login" : "",
+ su->fast_startup ? " fast-start" : ""));
+
+ if (su->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 (su->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);
+ errexec(shell);
+}
- setusershell ();
- while ((line = getusershell ()) != NULL)
- {
- if (*line != '#' && !strcmp (line, shell))
- {
- endusershell ();
- return false;
+/* Return true if SHELL is a restricted shell (one not returned by
+ * getusershell), else false, meaning it is a standard shell.
+ */
+static bool is_restricted_shell(const char *shell)
+{
+ char *line;
+
+ setusershell();
+ while ((line = getusershell()) != NULL) {
+ if (*line != '#' && !strcmp(line, shell)) {
+ endusershell();
+ return false;
+ }
}
- }
- endusershell ();
- return true;
+ endusershell();
+
+ DBG(MISC, ul_debug("%s is restricted shell (not in /etc/shells)", shell));
+ return true;
}
-static void __attribute__((__noreturn__))
-usage(void)
+static void usage_common(void)
{
- if (su_mode == RUNUSER_MODE) {
- fputs(USAGE_HEADER, stdout);
- printf (_(" %s [options] -u <user> [[--] <command>]\n"), program_invocation_short_name);
- printf (_(" %s [options] [-] [<user> [<argument>...]]\n"), program_invocation_short_name);
- fputs (_("\n"
- "Run <command> with the effective user ID and group ID of <user>. If -u is\n"
- "not given, fall back to su(1)-compatible semantics and execute standard shell.\n"
- "The options -c, -f, -l, and -s are mutually exclusive with -u.\n"), stdout);
+ fputs(_(" -m, -p, --preserve-environment do not reset environment variables\n"), stdout);
+ fputs(_(" -w, --whitelist-environment <list> don't reset specified variables\n"), stdout);
+ fputs(USAGE_SEPARATOR, stdout);
+
+ fputs(_(" -g, --group <group> specify the primary group\n"), stdout);
+ fputs(_(" -G, --supp-group <group> specify a supplemental group\n"), stdout);
+ fputs(USAGE_SEPARATOR, stdout);
+
+ fputs(_(" -, -l, --login make the shell a login shell\n"), stdout);
+ fputs(_(" -c, --command <command> pass a single command to the shell with -c\n"), stdout);
+ fputs(_(" --session-command <command> pass a single command to the shell with -c\n"
+ " and do not create a new session\n"), stdout);
+ fputs(_(" -f, --fast pass -f to the shell (for csh or tcsh)\n"), stdout);
+ fputs(_(" -s, --shell <shell> run <shell> if /etc/shells allows it\n"), stdout);
+ fputs(_(" -P, --pty create a new pseudo-terminal\n"), stdout);
+
+ fputs(USAGE_SEPARATOR, stdout);
+ printf(USAGE_HELP_OPTIONS(33));
+}
- fputs(USAGE_OPTIONS, stdout);
+static void usage_runuser(void)
+{
+ fputs(USAGE_HEADER, stdout);
+ fprintf(stdout,
+ _(" %1$s [options] -u <user> [[--] <command>]\n"
+ " %1$s [options] [-] [<user> [<argument>...]]\n"),
+ program_invocation_short_name);
+
+ fputs(USAGE_SEPARATOR, stdout);
+ fputs(_("Run <command> with the effective user ID and group ID of <user>. If -u is\n"
+ "not given, fall back to su(1)-compatible semantics and execute standard shell.\n"
+ "The options -c, -f, -l, and -s are mutually exclusive with -u.\n"), stdout);
+
+ fputs(USAGE_OPTIONS, stdout);
+ fputs(_(" -u, --user <user> username\n"), stdout);
+ usage_common();
+ fputs(USAGE_SEPARATOR, stdout);
+
+ fprintf(stdout, USAGE_MAN_TAIL("runuser(1)"));
+}
- fputs (_(" -u, --user <user> username\n"), stdout);
+static void usage_su(void)
+{
+ fputs(USAGE_HEADER, stdout);
+ fprintf(stdout,
+ _(" %s [options] [-] [<user> [<argument>...]]\n"),
+ program_invocation_short_name);
- } else {
- fputs(USAGE_HEADER, stdout);
- printf (_(" %s [options] [-] [<user> [<argument>...]]\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> is not given, root is assumed.\n"), stdout);
+ fputs(USAGE_SEPARATOR, stdout);
+ fputs(_("Change the effective user ID and group ID to that of <user>.\n"
+ "A mere - implies -l. If <user> is not given, root is assumed.\n"), stdout);
- fputs(USAGE_OPTIONS, stdout);
- }
+ fputs(USAGE_OPTIONS, stdout);
+ usage_common();
- fputs (_(" -m, -p, --preserve-environment do not reset environment variables\n"), stdout);
- fputs (_(" -g, --group <group> specify the primary group\n"), stdout);
- fputs (_(" -G, --supp-group <group> specify a supplemental group\n\n"), stdout);
+ fprintf(stdout, USAGE_MAN_TAIL("su(1)"));
+}
- fputs (_(" -, -l, --login make the shell a login shell\n"), stdout);
- fputs (_(" -c, --command <command> pass a single command to the shell with -c\n"), stdout);
- fputs (_(" --session-command <command> pass a single command to the shell with -c\n"
- " and do not create a new session\n"), stdout);
- fputs (_(" -f, --fast pass -f to the shell (for csh or tcsh)\n"), stdout);
- fputs (_(" -s, --shell <shell> run <shell> if /etc/shells allows it\n"), stdout);
+static void __attribute__((__noreturn__)) usage(int mode)
+{
+ if (mode == SU_MODE)
+ usage_su();
+ else
+ usage_runuser();
- fputs(USAGE_SEPARATOR, stdout);
- print_usage_help_options(33);
- printf(USAGE_MAN_TAIL(su_mode == SU_MODE ? "su(1)" : "runuser(1)"));
- exit(EXIT_SUCCESS);
+ exit(EXIT_SUCCESS);
}
-static
-void load_config(void)
+static void load_config(void *data)
{
- switch (su_mode) {
- case SU_MODE:
- logindefs_load_file(_PATH_LOGINDEFS_SU);
- break;
- case RUNUSER_MODE:
- logindefs_load_file(_PATH_LOGINDEFS_RUNUSER);
- break;
- default:
- abort();
- break;
- }
+ struct su_context *su = (struct su_context *) data;
- logindefs_load_file(_PATH_LOGINDEFS);
+ DBG(MISC, ul_debug("loading logindefs"));
+ logindefs_load_file(_PATH_LOGINDEFS);
+ logindefs_load_file(su->runuser ? _PATH_LOGINDEFS_RUNUSER : _PATH_LOGINDEFS_SU);
}
/*
* Returns 1 if the current user is not root
*/
-static int
-evaluate_uid(void)
-{
- const uid_t ruid = getuid();
- const uid_t euid = geteuid();
-
- /* if we're really root and aren't running setuid */
- return (uid_t) 0 == ruid && ruid == euid ? 0 : 1;
-}
-
-static gid_t
-add_supp_group(const char *name, gid_t **groups, size_t *ngroups)
-{
- struct group *gr;
-
- if (*ngroups >= NGROUPS_MAX)
- errx(EXIT_FAILURE,
- P_("specifying more than %d supplemental group is not possible",
- "specifying more than %d supplemental groups is not possible",
- NGROUPS_MAX - 1), NGROUPS_MAX - 1);
-
- gr = getgrnam(name);
- if (!gr)
- errx(EXIT_FAILURE, _("group %s does not exist"), name);
-
- *groups = xrealloc(*groups, sizeof(gid_t) * (*ngroups + 1));
- (*groups)[*ngroups] = gr->gr_gid;
- (*ngroups)++;
-
- return gr->gr_gid;
-}
-
-int
-su_main (int argc, char **argv, int mode)
-{
- int optc;
- const char *new_user = DEFAULT_USER, *runuser_user = NULL;
- const char *command = NULL;
- int request_same_session = 0;
- const char *shell = NULL;
- struct passwd *pw;
- struct passwd pw_copy;
-
- gid_t *groups = NULL;
- size_t ngroups = 0;
- bool use_supp = false;
- bool use_gid = false;
- gid_t gid = 0;
-
- static const struct option 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'},
- {"user", required_argument, NULL, 'u'}, /* runuser only */
- {"help", no_argument, NULL, 'h'},
- {"version", no_argument, NULL, 'V'},
- {NULL, 0, NULL, 0}
- };
-
- setlocale (LC_ALL, "");
- bindtextdomain (PACKAGE, LOCALEDIR);
- textdomain (PACKAGE);
- atexit(close_stdout);
-
- su_mode = mode;
- fast_startup = false;
- simulate_login = false;
- change_environment = true;
-
- while ((optc = getopt_long (argc, argv, "c:fg:G:lmps:u: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':
- use_gid = true;
- gid = add_supp_group(optarg, &groups, &ngroups);
- break;
-
- case 'G':
- use_supp = true;
- add_supp_group(optarg, &groups, &ngroups);
- break;
-
- case 'l':
- simulate_login = true;
- break;
-
- case 'm':
- case 'p':
- change_environment = false;
- break;
-
- case 's':
- shell = optarg;
- break;
-
- case 'u':
- if (su_mode != RUNUSER_MODE) {
- warnx(_("invalid option -- 'u'"));
- errtryhelp(EXIT_FAILURE);
- }
- runuser_user = optarg;
- break;
-
- case 'h':
- usage();
-
- case 'V':
- printf(UTIL_LINUX_VERSION);
- exit(EXIT_SUCCESS);
+static int is_not_root(void)
+{
+ const uid_t ruid = getuid();
+ const uid_t euid = geteuid();
- default:
- errtryhelp(EXIT_FAILURE);
- }
- }
-
- restricted = evaluate_uid ();
-
- if (optind < argc && !strcmp (argv[optind], "-"))
- {
- simulate_login = true;
- ++optind;
- }
-
- if (simulate_login && !change_environment) {
- warnx(_("ignoring --preserve-environment, it's mutually exclusive with --login"));
- change_environment = true;
- }
-
- switch (su_mode) {
- case RUNUSER_MODE:
- if (runuser_user) {
- /* runuser -u <user> <command> */
- new_user = runuser_user;
- if (shell || fast_startup || command || simulate_login) {
- errx(EXIT_FAILURE,
- _("options --{shell,fast,command,session-command,login} and "
- "--user are mutually exclusive"));
- }
- if (optind == argc)
- errx(EXIT_FAILURE, _("no command was specified"));
-
- break;
- }
- /* fallthrough if -u <user> is not specified, then follow
- * traditional su(1) behavior
- */
- /* fallthrough */
- case SU_MODE:
- if (optind < argc)
- new_user = argv[optind++];
- break;
- default:
- abort();
- break;
- }
-
- if ((use_supp || 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 (use_supp && !use_gid)
- pw->pw_gid = groups[0];
- else if (use_gid)
- pw->pw_gid = gid;
-
- authenticate (pw);
-
- if (request_same_session || !command || !pw->pw_uid)
- same_session = 1;
-
- /* initialize shell variable only if "-u <user>" not specified */
- if (runuser_user) {
- shell = NULL;
- } else {
- 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, ngroups);
-
- if (!simulate_login || command)
- suppress_pam_info = 1; /* don't print PAM info messages */
-
- 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);
-
- if (shell)
- run_shell (shell, command, argv + optind, max (0, argc - optind));
- else {
- execvp(argv[optind], &argv[optind]);
- err(EXIT_FAILURE, _("failed to execute %s"), argv[optind]);
- }
-}
-
-// vim: sw=2 cinoptions=>4,n-2,{2,^-2,\:2,=2,g0,h2,p5,t0,+2,(0,u0,w1,m1
+ /* if we're really root and aren't running setuid */
+ return (uid_t) 0 == ruid && ruid == euid ? 0 : 1;
+}
+
+static gid_t add_supp_group(const char *name, gid_t **groups, size_t *ngroups)
+{
+ struct group *gr;
+
+ if (*ngroups >= NGROUPS_MAX)
+ errx(EXIT_FAILURE,
+ P_("specifying more than %d supplemental group is not possible",
+ "specifying more than %d supplemental groups is not possible",
+ NGROUPS_MAX - 1), NGROUPS_MAX - 1);
+
+ gr = getgrnam(name);
+ if (!gr)
+ errx(EXIT_FAILURE, _("group %s does not exist"), name);
+
+ DBG(MISC, ul_debug("add %s group [name=%s, GID=%d]", name, gr->gr_name, (int) gr->gr_gid));
+
+ *groups = xrealloc(*groups, sizeof(gid_t) * (*ngroups + 1));
+ (*groups)[*ngroups] = gr->gr_gid;
+ (*ngroups)++;
+
+ return gr->gr_gid;
+}
+
+int su_main(int argc, char **argv, int mode)
+{
+ struct su_context _su = {
+ .conv = { supam_conv, NULL },
+ .runuser = (mode == RUNUSER_MODE ? 1 : 0),
+ .change_environment = 1,
+ .new_user = DEFAULT_USER,
+#ifdef USE_PTY
+ .pty_master = -1,
+ .pty_slave = -1,
+ .pty_sigfd = -1,
+#endif
+ }, *su = &_su;
+
+ int optc;
+ char *command = NULL;
+ int request_same_session = 0;
+ char *shell = NULL;
+
+ gid_t *groups = NULL;
+ size_t ngroups = 0;
+ bool use_supp = false;
+ bool use_gid = false;
+ gid_t gid = 0;
+
+ static const struct option 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'},
+ {"pty", no_argument, NULL, 'P'},
+ {"shell", required_argument, NULL, 's'},
+ {"group", required_argument, NULL, 'g'},
+ {"supp-group", required_argument, NULL, 'G'},
+ {"user", required_argument, NULL, 'u'}, /* runuser only */
+ {"whitelist-environment", required_argument, NULL, 'w'},
+ {"help", no_argument, 0, 'h'},
+ {"version", no_argument, 0, 'V'},
+ {NULL, 0, NULL, 0}
+ };
+ static const ul_excl_t excl[] = { /* rows and cols in ASCII order */
+ { 'm', 'w' }, /* preserve-environment, whitelist-environment */
+ { 'p', 'w' }, /* preserve-environment, whitelist-environment */
+ { 0 }
+ };
+ int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
+
+ setlocale(LC_ALL, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+ close_stdout_atexit();
+
+ su_init_debug();
+ su->conv.appdata_ptr = (void *) su;
+
+ while ((optc =
+ getopt_long(argc, argv, "c:fg:G:lmpPs:u:hVw:", longopts,
+ NULL)) != -1) {
+
+ err_exclusive_options(optc, longopts, excl, excl_st);
+
+ switch (optc) {
+ case 'c':
+ command = optarg;
+ break;
+
+ case 'C':
+ command = optarg;
+ request_same_session = 1;
+ break;
+
+ case 'f':
+ su->fast_startup = true;
+ break;
+
+ case 'g':
+ use_gid = true;
+ gid = add_supp_group(optarg, &groups, &ngroups);
+ break;
+
+ case 'G':
+ use_supp = true;
+ add_supp_group(optarg, &groups, &ngroups);
+ break;
+
+ case 'l':
+ su->simulate_login = true;
+ break;
+
+ case 'm':
+ case 'p':
+ su->change_environment = false;
+ break;
+
+ case 'w':
+ env_whitelist_from_string(su, optarg);
+ break;
+
+ case 'P':
+#ifdef USE_PTY
+ su->pty = 1;
+#else
+ errx(EXIT_FAILURE, _("--pty is not supported for your system"));
+#endif
+ break;
+
+ case 's':
+ shell = optarg;
+ break;
+
+ case 'u':
+ if (!su->runuser)
+ errtryhelp(EXIT_FAILURE);
+ su->runuser_uopt = 1;
+ su->new_user = optarg;
+ break;
+
+ case 'h':
+ usage(mode);
+
+ case 'V':
+ print_version(EXIT_SUCCESS);
+ default:
+ errtryhelp(EXIT_FAILURE);
+ }
+ }
+
+ su->restricted = is_not_root();
+
+ if (optind < argc && !strcmp(argv[optind], "-")) {
+ su->simulate_login = true;
+ ++optind;
+ }
+
+ if (su->simulate_login && !su->change_environment) {
+ warnx(_
+ ("ignoring --preserve-environment, it's mutually exclusive with --login"));
+ su->change_environment = true;
+ }
+
+ switch (mode) {
+ case RUNUSER_MODE:
+ /* runuser -u <user> <command>
+ *
+ * If -u <user> is not specified, then follow traditional su(1) behavior and
+ * fallthrough
+ */
+ if (su->runuser_uopt) {
+ if (shell || su->fast_startup || command || su->simulate_login)
+ errx(EXIT_FAILURE,
+ _("options --{shell,fast,command,session-command,login} and "
+ "--user are mutually exclusive"));
+ if (optind == argc)
+ errx(EXIT_FAILURE, _("no command was specified"));
+ break;
+ }
+ /* fallthrough */
+ case SU_MODE:
+ if (optind < argc)
+ su->new_user = argv[optind++];
+ break;
+ }
+
+ if ((use_supp || use_gid) && su->restricted)
+ errx(EXIT_FAILURE,
+ _("only root can specify alternative groups"));
+
+ logindefs_set_loader(load_config, (void *) su);
+ init_tty(su);
+
+ su->pwd = xgetpwnam(su->new_user, &su->pwdbuf);
+ if (!su->pwd
+ || !su->pwd->pw_passwd
+ || !su->pwd->pw_name || !*su->pwd->pw_name
+ || !su->pwd->pw_dir || !*su->pwd->pw_dir)
+ errx(EXIT_FAILURE,
+ _("user %s does not exist or the user entry does not "
+ "contain all the required fields"), su->new_user);
+
+ su->new_user = su->pwd->pw_name;
+ su->old_user = xgetlogin();
+
+ if (!su->pwd->pw_shell || !*su->pwd->pw_shell)
+ su->pwd->pw_shell = DEFAULT_SHELL;
+
+ if (use_supp && !use_gid)
+ su->pwd->pw_gid = groups[0];
+ else if (use_gid)
+ su->pwd->pw_gid = gid;
+
+ supam_authenticate(su);
+
+ if (request_same_session || !command || !su->pwd->pw_uid)
+ su->same_session = 1;
+
+ /* initialize shell variable only if "-u <user>" not specified */
+ if (su->runuser_uopt) {
+ shell = NULL;
+ } else {
+ if (!shell && !su->change_environment)
+ shell = getenv("SHELL");
+
+ if (shell
+ && getuid() != 0
+ && is_restricted_shell(su->pwd->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"), su->pwd->pw_shell);
+ shell = NULL;
+ }
+ shell = xstrdup(shell ? shell : su->pwd->pw_shell);
+ }
+
+ init_groups(su, groups, ngroups);
+
+ if (!su->simulate_login || command)
+ su->suppress_pam_info = 1; /* don't print PAM info messages */
+
+ supam_open_session(su);
+
+ create_watching_parent(su);
+ /* Now we're in the child. */
+
+ change_identity(su->pwd);
+ if (!su->same_session || su->pty) {
+ DBG(MISC, ul_debug("call setsid()"));
+ setsid();
+ }
+#ifdef USE_PTY
+ if (su->pty)
+ pty_init_slave(su);
+#endif
+ /* Set environment after pam_open_session, which may put KRB5CCNAME
+ into the pam_env, etc. */
+
+ modify_environment(su, shell);
+
+ if (su->simulate_login && chdir(su->pwd->pw_dir) != 0)
+ warn(_("warning: cannot change directory to %s"), su->pwd->pw_dir);
+
+ if (shell)
+ run_shell(su, shell, command, argv + optind, max(0, argc - optind));
+
+ execvp(argv[optind], &argv[optind]);
+ err(EXIT_FAILURE, _("failed to execute %s"), argv[optind]);
+}
projects / thirdparty / util-linux.git / blobdiff