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util-linux/0201-su-move-generic-su-code-to-su-common.c.patch
Karel Zak 7443d56081 2.22.1-3: enable su(1) and runuser(1) 
Signed-off-by: Karel Zak <kzak@redhat.com>
2012-11-01 15:09:04 +01:00

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From 1874fa1ef38ce41eaf61b1aada25fac5f6966839 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Thu, 1 Nov 2012 12:38:48 +0100
Subject: [PATCH 201/208] su: move generic su code to su-common.c
Signed-off-by: Karel Zak <kzak@redhat.com>
---
login-utils/Makemodule.am | 2 +
login-utils/su-common.c | 759 ++++++++++++++++++++++++++++++++++++++++++++++
login-utils/su-common.h | 12 +
login-utils/su.c | 754 +--------------------------------------------
4 files changed, 776 insertions(+), 751 deletions(-)
create mode 100644 login-utils/su-common.c
create mode 100644 login-utils/su-common.h
diff --git a/login-utils/Makemodule.am b/login-utils/Makemodule.am
index e10da46..b918f00 100644
--- a/login-utils/Makemodule.am
+++ b/login-utils/Makemodule.am
@@ -83,6 +83,8 @@ bin_PROGRAMS += su
dist_man_MANS += login-utils/su.1
su_SOURCES = \
login-utils/su.c \
+ login-utils/su-common.c \
+ login-utils/su-common.h \
login-utils/logindefs.c \
login-utils/logindefs.h
su_CFLAGS = $(SUID_CFLAGS) $(AM_CFLAGS)
diff --git a/login-utils/su-common.c b/login-utils/su-common.c
new file mode 100644
index 0000000..f1f46aa
--- /dev/null
+++ b/login-utils/su-common.c
@@ -0,0 +1,759 @@
+/* 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 implemenation by David MacKenzie <djm@gnu.ai.mit.edu>. */
+
+enum
+{
+ 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"
+#include "su-common.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;
+
+/* SU_MODE_{RUNUSER,SU} */
+static int su_mode;
+
+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 ();
+}
+
+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"));
+ }
+}
+
+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);
+
+ 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
diff --git a/login-utils/su-common.h b/login-utils/su-common.h
new file mode 100644
index 0000000..4e4dc9d
--- /dev/null
+++ b/login-utils/su-common.h
@@ -0,0 +1,12 @@
+#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 */
+
diff --git a/login-utils/su.c b/login-utils/su.c
index f11c757..6179e1b 100644
--- a/login-utils/su.c
+++ b/login-utils/su.c
@@ -1,754 +1,6 @@
-/* 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
+#include "su-common.h"
- 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 implemenation by David MacKenzie <djm@gnu.ai.mit.edu>. */
-
-enum
-{
- 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 ();
-}
-
-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)
+int main (int argc, char **argv)
{
- 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"));
- }
+ return su_main(argc, argv, SU_MODE);
}
-
-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);
-
- 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
--
1.7.11.7
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