coreutils/coreutils-pam.patch

--- coreutils-5.92/src/Makefile.am.pam	2005-10-24 17:58:21.000000000 +0100
+++ coreutils-5.92/src/Makefile.am	2005-10-24 17:58:21.000000000 +0100
@@ -93,7 +93,7 @@
 
 uptime_LDADD = $(LDADD) $(GETLOADAVG_LIBS)
 
-su_LDADD = $(LDADD) $(LIB_CRYPT)
+su_LDADD = $(LDADD) $(LIB_CRYPT) @LIB_PAM@
 
 $(PROGRAMS): ../lib/libcoreutils.a
 
--- coreutils-5.92/src/su.c.pam	2005-10-24 17:58:21.000000000 +0100
+++ coreutils-5.92/src/su.c	2005-10-24 18:06:22.000000000 +0100
@@ -38,6 +38,16 @@
    restricts who can su to UID 0 accounts.  RMS considers that to
    be fascist.
 
+#ifdef USE_PAM
+
+   Actually, with PAM, su has nothing to do with whether or not a
+   wheel group is enforced by su.  RMS tries to restrict your access
+   to a su which implements the wheel group, but PAM considers that
+   to be fascist, and gives the user/sysadmin the opportunity to
+   enforce a wheel group by proper editing of /etc/pam.conf
+
+#endif
+
    Options:
    -, -l, --login	Make the subshell a login shell.
 			Unset all environment variables except
@@ -81,6 +91,15 @@
    prototype (returning `int') in <unistd.h>.  */
 #define getusershell _getusershell_sys_proto_
 
+#ifdef USE_PAM
+# include <signal.h>
+# include <sys/wait.h>
+# include <sys/fsuid.h>
+# include <unistd.h>
+# include <security/pam_appl.h>
+# include <security/pam_misc.h>
+#endif /* USE_PAM */
+
 #include "system.h"
 #include "dirname.h"
 
@@ -150,7 +169,9 @@
 /* The user to become if none is specified.  */
 #define DEFAULT_USER "root"
 
+#ifndef USE_PAM
 char *crypt ();
+#endif
 char *getpass ();
 char *getusershell ();
 void endusershell ();
@@ -158,8 +179,13 @@
 
 extern char **environ;
 
-static void run_shell (char const *, char const *, char **, size_t)
+static void run_shell (char const *, char const *, char **, size_t,
+	const struct passwd *)
+#ifdef USE_PAM
+	;
+#else
      ATTRIBUTE_NORETURN;
+#endif
 
 /* The name this program was run with.  */
 char *program_name;
@@ -248,7 +274,22 @@
 }
 #endif
 
+#ifdef USE_PAM
+static pam_handle_t *pamh = NULL;
+static int retval;
+static struct pam_conv conv = {
+  misc_conv,
+  NULL
+};
+
+#define PAM_BAIL_P if (retval) { \
+  pam_end(pamh, PAM_SUCCESS); \
+  return 0; \
+}
+#endif
+
 /* Ask the user for a password.
+   If PAM is in use, let PAM ask for the password if necessary.
    Return true if the user gives the correct password for entry PW,
    false if not.  Return true without asking for a password if run by UID 0
    or if PW has an empty password.  */
@@ -256,6 +297,44 @@
 static bool
 correct_password (const struct passwd *pw)
 {
+#ifdef USE_PAM
+  struct passwd *caller;
+  char *tty_name, *ttyn;
+  retval = pam_start(PROGRAM_NAME, pw->pw_name, &conv, &pamh);
+  PAM_BAIL_P;
+
+  if (getuid() != 0 && !isatty(0)) {
+	fprintf(stderr, "standard in must be a tty\n");
+	exit(1);
+  }
+
+  caller = getpwuid(getuid());
+  if(caller != NULL && caller->pw_name != NULL) {
+	  retval = pam_set_item(pamh, PAM_RUSER, caller->pw_name);
+	  PAM_BAIL_P;
+  }
+
+  ttyn = ttyname(0);
+  if (ttyn) {
+    if (strncmp(ttyn, "/dev/", 5) == 0)
+       tty_name = ttyn+5;
+    else
+       tty_name = ttyn;
+    retval = pam_set_item(pamh, PAM_TTY, tty_name);
+    PAM_BAIL_P;
+  }
+  retval = pam_authenticate(pamh, 0);
+  PAM_BAIL_P;
+  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);
+    PAM_BAIL_P;
+  }
+  PAM_BAIL_P;
+  /* must be authenticated if this point was reached */
+  return 1;
+#else /* !USE_PAM */
   char *unencrypted, *encrypted, *correct;
 #if HAVE_GETSPNAM && HAVE_STRUCT_SPWD_SP_PWDP
   /* Shadow passwd stuff for SVR3 and maybe other systems.  */
@@ -280,6 +359,7 @@
   encrypted = crypt (unencrypted, correct);
   memset (unencrypted, 0, strlen (unencrypted));
   return STREQ (encrypted, correct);
+#endif /* !USE_PAM */
 }
 
 /* Update `environ' for the new shell based on PW, with SHELL being
@@ -293,12 +373,18 @@
       /* Leave TERM unchanged.  Set HOME, SHELL, USER, LOGNAME, PATH.
          Unset all other environment variables.  */
       char const *term = getenv ("TERM");
+      char const *display = getenv ("DISPLAY");
+      char const *xauthority = getenv ("XAUTHORITY");
       if (term)
 	term = xstrdup (term);
       environ = xmalloc ((6 + !!term) * sizeof (char *));
       environ[0] = NULL;
       if (term)
 	xsetenv ("TERM", term);
+      if (display)
+	xsetenv ("DISPLAY", display);
+      if (xauthority)
+	xsetenv ("XAUTHORITY", xauthority);
       xsetenv ("HOME", pw->pw_dir);
       xsetenv ("SHELL", shell);
       xsetenv ("USER", pw->pw_name);
@@ -331,8 +417,13 @@
 {
 #ifdef HAVE_INITGROUPS
   errno = 0;
-  if (initgroups (pw->pw_name, pw->pw_gid) == -1)
+  if (initgroups (pw->pw_name, pw->pw_gid) == -1) {
+#ifdef USE_PAM
+    pam_close_session(pamh, 0);
+    pam_end(pamh, PAM_ABORT);
+#endif
     error (EXIT_FAIL, errno, _("cannot set groups"));
+  }
   endgrent ();
 #endif
   if (setgid (pw->pw_gid))
@@ -341,6 +432,31 @@
     error (EXIT_FAIL, errno, _("cannot set user id"));
 }
 
+#ifdef USE_PAM
+static int caught=0;
+/* Signal handler for parent process later */
+static void su_catch_sig(int sig)
+{
+  ++caught;
+}
+
+int
+pam_copyenv (pam_handle_t *pamh)
+{
+  char **env;
+
+  env = pam_getenvlist(pamh);
+  if(env) {
+    while(*env) {
+	if (putenv (*env))
+	  xalloc_die ();
+	env++;
+    }
+  }
+  return(0);
+}
+#endif
+
 /* 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
@@ -348,17 +464,49 @@
 
 static void
 run_shell (char const *shell, char const *command, char **additional_args,
-	   size_t n_additional_args)
+	   size_t n_additional_args, const struct passwd *pw)
 {
   size_t n_args = 1 + fast_startup + 2 * !!command + n_additional_args + 1;
   char const **args = xnmalloc (n_args, sizeof *args);
   size_t argno = 1;
+#ifdef USE_PAM
+  int child;
+  sigset_t ourset;
+  int status;
+
+  retval = pam_open_session(pamh,0);
+  if (retval != PAM_SUCCESS) {
+    fprintf (stderr, "could not open session\n");
+    exit (1);
+  }
+
+/* do this at the last possible moment, because environment variables may
+   be passed even in the session phase
+*/
+  if(pam_copyenv(pamh) != PAM_SUCCESS)
+     fprintf (stderr, "error copying PAM environment\n");
+  
+  /* Credentials should be set in the parent */ 
+  if (pam_setcred(pamh, PAM_ESTABLISH_CRED) != PAM_SUCCESS) {
+    pam_close_session(pamh, 0);
+    fprintf(stderr, "could not set PAM credentials\n");
+    exit(1);
+  }
+
+  child = fork();
+  if (child == 0) {  /* child shell */
+  change_identity (pw);
+  pam_end(pamh, 0);
+#endif
 
   if (simulate_login)
     {
       char *arg0;
       char *shell_basename;
 
+      if(chdir(pw->pw_dir))
+	      error(0, errno, _("warning: cannot change directory to %s"), pw->pw_dir);
+
       shell_basename = base_name (shell);
       arg0 = xmalloc (strlen (shell_basename) + 2);
       arg0[0] = '-';
@@ -383,6 +531,66 @@
     error (0, errno, "%s", shell);
     exit (exit_status);
   }
+#ifdef USE_PAM
+  } else if (child == -1) {
+      fprintf(stderr, "can not fork user shell: %s", strerror(errno));
+      pam_setcred(pamh, PAM_DELETE_CRED | PAM_SILENT);
+      pam_close_session(pamh, 0);
+      pam_end(pamh, PAM_ABORT);
+      exit(1);
+  }
+  /* parent only */
+  sigfillset(&ourset);
+  if (sigprocmask(SIG_BLOCK, &ourset, NULL)) {
+    fprintf(stderr, "%s: signal malfunction\n", PROGRAM_NAME);
+    caught = 1;
+  }
+  if (!caught) {
+    struct sigaction action;
+    action.sa_handler = su_catch_sig;
+    sigemptyset(&action.sa_mask);
+    action.sa_flags = 0;
+    sigemptyset(&ourset);
+    if (sigaddset(&ourset, SIGTERM)
+        || sigaddset(&ourset, SIGALRM)
+        || sigaction(SIGTERM, &action, NULL)
+        || sigprocmask(SIG_UNBLOCK, &ourset, NULL)) {
+      fprintf(stderr, "%s: signal masking malfunction\n", PROGRAM_NAME);
+      caught = 1;
+    }
+  }
+  if (!caught) {
+    do {
+      int pid;
+
+      pid = waitpid(-1, &status, WUNTRACED);
+
+      if (WIFSTOPPED(status)) {
+          kill(getpid(), SIGSTOP);
+          /* once we get here, we must have resumed */
+          kill(pid, SIGCONT);
+      }
+    } while (WIFSTOPPED(status));
+  }
+
+  if (caught) {
+    fprintf(stderr, "\nSession terminated, killing shell...");
+    kill (child, SIGTERM);
+  }
+  /* Not checking retval on this because we need to call close session */
+  pam_setcred(pamh, PAM_DELETE_CRED | PAM_SILENT);
+  retval = pam_close_session(pamh, 0);
+  PAM_BAIL_P;
+  retval = pam_end(pamh, PAM_SUCCESS);
+  PAM_BAIL_P;
+  if (caught) {
+    sleep(2);
+    kill(child, SIGKILL);
+    fprintf(stderr, " ...killed.\n");
+    exit(-1);
+  }
+  exit (WEXITSTATUS(status));
+#endif /* USE_PAM */
 }
 
 /* Return true if SHELL is a restricted shell (one not returned by
@@ -550,9 +758,11 @@
   shell = xstrdup (shell ? shell : pw->pw_shell);
   modify_environment (pw, shell);
 
+#ifndef USE_PAM
   change_identity (pw);
+#endif
   if (simulate_login && chdir (pw->pw_dir) != 0)
     error (0, errno, _("warning: cannot change directory to %s"), pw->pw_dir);
 
-  run_shell (shell, command, argv + optind, MAX (0, argc - optind));
+  run_shell (shell, command, argv + optind, MAX (0, argc - optind), pw);
 }
--- coreutils-5.92/doc/coreutils.texi.pam	2005-10-16 08:26:21.000000000 +0100
+++ coreutils-5.92/doc/coreutils.texi	2005-10-24 17:58:21.000000000 +0100
@@ -12746,8 +12746,11 @@
 @findex syslog
 @command{su} can optionally be compiled to use @code{syslog} to report
 failed, and optionally successful, @command{su} attempts.  (If the system
-supports @code{syslog}.)  However, GNU @command{su} does not check if the
-user is a member of the @code{wheel} group; see below.
+supports @code{syslog}.)
+
+This version of @command{su} has support for using PAM for
+authentication.  You can edit @file{/etc/pam.d/su} to customize its
+behaviour.
 
 The program accepts the following options.  Also see @ref{Common options}.
 
@@ -12828,33 +12831,6 @@
 the exit status of the subshell otherwise
 @end display
 
-@cindex wheel group, not supported
-@cindex group wheel, not supported
-@cindex fascism
-@subsection Why GNU @command{su} does not support the @samp{wheel} group
-
-(This section is by Richard Stallman.)
-
-@cindex Twenex
-@cindex MIT AI lab
-Sometimes a few of the users try to hold total power over all the
-rest.  For example, in 1984, a few users at the MIT AI lab decided to
-seize power by changing the operator password on the Twenex system and
-keeping it secret from everyone else.  (I was able to thwart this coup
-and give power back to the users by patching the kernel, but I
-wouldn't know how to do that in Unix.)
-
-However, occasionally the rulers do tell someone.  Under the usual
-@command{su} mechanism, once someone learns the root password who
-sympathizes with the ordinary users, he or she can tell the rest.  The
-``wheel group'' feature would make this impossible, and thus cement the
-power of the rulers.
-
-I'm on the side of the masses, not that of the rulers.  If you are
-used to supporting the bosses and sysadmins in whatever they do, you
-might find this idea strange at first.
-
-
 @node Process control
 @chapter Process control
 
--- coreutils-5.92/configure.ac.pam	2005-10-24 17:58:21.000000000 +0100
+++ coreutils-5.92/configure.ac	2005-10-24 17:58:21.000000000 +0100
@@ -28,6 +28,13 @@
 AB_INIT()
 AM_INIT_AUTOMAKE([1.8.3 gnits dist-bzip2])
 
+dnl Give the chance to enable PAM
+AC_ARG_ENABLE(pam, dnl
+[  --enable-pam              Enable use of the PAM libraries],
+[AC_DEFINE(USE_PAM, 1, [Define if you want to use PAM])
+LIB_PAM="-ldl -lpam -lpam_misc"
+AC_SUBST(LIB_PAM)])
+
 gl_DEFAULT_POSIX2_VERSION
 gl_USE_SYSTEM_EXTENSIONS
 gl_PERL
--- coreutils-5.92/config.hin.pam	2005-10-24 17:58:21.000000000 +0100
+++ coreutils-5.92/config.hin	2005-10-24 17:58:21.000000000 +0100
@@ -1526,6 +1526,9 @@
 /* Define if you want access control list support. */
 #undef USE_ACL
 
+/* Define if you want to use PAM */
+#undef USE_PAM
+
 /* Version number of package */
 #undef VERSION