nixpkgs/pkgs/tools/misc/su/su-pam.patch

--- src/getdef.c
+++ src/getdef.c
@@ -0,0 +1,257 @@
+/* Copyright (C) 2003, 2004, 2005 Thorsten Kukuk
+   Author: Thorsten Kukuk <kukuk@suse.de>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License version 2 as
+   published by the Free Software Foundation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+#include "getdef.h"
+
+struct item {
+  char *name;         /* name of the option.  */
+  char *value;        /* value of the option.  */
+  struct item *next;  /* pointer to next option.  */
+};
+
+static struct item *list = NULL;
+
+void
+free_getdef_data (void)
+{
+  struct item *ptr;
+
+  ptr = list;
+  while (ptr != NULL)
+    {
+      struct item *tmp;
+      tmp = ptr->next;
+      free (ptr->name);
+      free (ptr->value);
+      free (ptr);
+      ptr = tmp;
+    }
+
+  list = NULL;
+}
+
+/* Add a new entry to the list.  */
+static void
+store (const char *name, const char *value)
+{
+  struct item *new = malloc (sizeof (struct item));
+
+  if (new == NULL)
+    abort ();
+
+  if (name == NULL)
+    abort ();
+
+  new->name = strdup (name);
+  new->value = strdup (value?:"");
+  new->next = list;
+  list = new;
+}
+
+/* search a special entry in the list and return the value.  */
+static const char *
+search (const char *name)
+{
+  struct item *ptr;
+
+  ptr = list;
+  while (ptr != NULL)
+    {
+      if (strcasecmp (name, ptr->name) == 0)
+	return ptr->value;
+      ptr = ptr->next;
+    }
+
+  return NULL;
+}
+
+/* Load the login.defs file (/etc/login.defs)  */
+static void
+load_defaults_internal (const char *filename)
+{
+  FILE *fp;
+  char *buf = NULL;
+  size_t buflen = 0;
+
+  fp = fopen (filename, "r");
+  if (NULL == fp)
+    return;
+
+  while (!feof (fp))
+    {
+      char *tmp, *cp;
+#if defined(HAVE_GETLINE)
+      ssize_t n = getline (&buf, &buflen, fp);
+#elif defined (HAVE_GETDELIM)
+      ssize_t n = getdelim (&buf, &buflen, '\n', fp);
+#else
+      ssize_t n;
+
+      if (buf == NULL)
+        {
+          buflen = 8096;
+          buf = malloc (buflen);
+        }
+      buf[0] = '\0';
+      fgets (buf, buflen - 1, fp);
+      if (buf != NULL)
+        n = strlen (buf);
+      else
+        n = 0;
+#endif /* HAVE_GETLINE / HAVE_GETDELIM */
+      cp = buf;
+
+      if (n < 1)
+        break;
+
+      tmp = strchr (cp, '#');  /* remove comments */
+      if (tmp)
+        *tmp = '\0';
+      while (isspace ((int)*cp))    /* remove spaces and tabs */
+        ++cp;
+      if (*cp == '\0')        /* ignore empty lines */
+        continue;
+
+      if (cp[strlen (cp) - 1] == '\n')
+        cp[strlen (cp) - 1] = '\0';
+
+      tmp = strsep (&cp, " \t=");
+      if (cp != NULL)
+	while (isspace ((int)*cp) || *cp == '=')
+	  ++cp;
+
+      store (tmp, cp);
+    }
+  fclose (fp);
+
+  if (buf)
+    free (buf);
+}
+
+static void
+load_defaults (void)
+{
+  load_defaults_internal ("/etc/default/su");
+  load_defaults_internal ("/etc/login.defs");
+}
+
+int
+getdef_bool (const char *name, int dflt)
+{
+  const char *val;
+
+  if (list == NULL)
+    load_defaults ();
+
+  val = search (name);
+
+  if (val == NULL)
+    return dflt;
+
+  return (strcasecmp (val, "yes") == 0);
+}
+
+long
+getdef_num (const char *name, long dflt)
+{
+  const char *val;
+  char *cp;
+  long retval;
+
+  if (list == NULL)
+    load_defaults ();
+
+  val = search (name);
+
+  if (val == NULL)
+    return dflt;
+
+  retval = strtol (val, &cp, 0);
+  if (*cp != '\0' ||
+      ((retval == LONG_MAX || retval == LONG_MIN) && errno == ERANGE))
+    {
+      fprintf (stderr,
+	       "%s contains invalid numerical value: %s!\n",
+	       name, val);
+      retval = dflt;
+    }
+  return retval;
+}
+
+unsigned long
+getdef_unum (const char *name, unsigned long dflt)
+{
+  const char *val;
+  char *cp;
+  unsigned long retval;
+
+  if (list == NULL)
+    load_defaults ();
+
+  val = search (name);
+
+  if (val == NULL)
+    return dflt;
+
+  retval = strtoul (val, &cp, 0);
+  if (*cp != '\0' || (retval == ULONG_MAX && errno == ERANGE))
+    {
+      fprintf (stderr,
+	       "%s contains invalid numerical value: %s!\n",
+	       name, val);
+      retval = dflt;
+    }
+  return retval;
+}
+
+const char *
+getdef_str (const char *name, const char *dflt)
+{
+  const char *retval;
+
+  if (list == NULL)
+    load_defaults ();
+
+  retval = search (name);
+
+  return retval ?: dflt;
+}
+
+#if defined(TEST)
+
+int
+main ()
+{
+  printf ("CYPT=%s\n", getdef_str ("cRypt", "no"));
+  printf ("LOG_UNKFAIL_ENAB=%s\n", getdef_str ("log_unkfail_enab",""));
+  printf ("DOESNOTEXIST=%s\n", getdef_str ("DOESNOTEXIST","yes"));
+  return 0;
+}
+
+#endif
--- src/getdef.h
+++ src/getdef.h
@@ -0,0 +1,29 @@
+/* Copyright (C) 2003, 2005 Thorsten Kukuk
+   Author: Thorsten Kukuk <kukuk@suse.de>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License version 2 as
+   published by the Free Software Foundation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#ifndef _GETDEF_H_
+
+#define _GETDEF_H_ 1
+
+extern int getdef_bool (const char *name, int dflt);
+extern long getdef_num (const char *name, long dflt);
+extern unsigned long getdef_unum (const char *name, unsigned long dflt);
+extern const char *getdef_str (const char *name, const char *dflt);
+
+/* Free all data allocated by getdef_* calls before.  */
+extern void free_getdef_data (void);
+
+#endif /* _GETDEF_H_ */
--- src/su.c
+++ src/su.c
@@ -38,6 +38,12 @@
    restricts who can su to UID 0 accounts.  RMS considers that to
    be fascist.
 
+   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.d/su
+
    Compile-time options:
    -DSYSLOG_SUCCESS	Log successful su's (by default, to root) with syslog.
    -DSYSLOG_FAILURE	Log failed su's (by default, to root) with syslog.
@@ -53,6 +59,13 @@
 #include <sys/types.h>
 #include <pwd.h>
 #include <grp.h>
+#ifdef USE_PAM
+#include <security/pam_appl.h>
+#include <security/pam_misc.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <sys/fsuid.h>
+#endif
 
 /* Hide any system prototype for getusershell.
    This is necessary because some Cray systems have a conflicting
@@ -66,6 +79,9 @@
 
 #if HAVE_SYSLOG_H && HAVE_SYSLOG
 # include <syslog.h>
+# define SYSLOG_SUCCESS  1
+# define SYSLOG_FAILURE  1
+# define SYSLOG_NON_ROOT 1
 #else
 # undef SYSLOG_SUCCESS
 # undef SYSLOG_FAILURE
@@ -99,19 +115,13 @@
 # include <paths.h>
 #endif
 
+#include "getdef.h"
+
 /* The default PATH for simulated logins to non-superuser accounts.  */
-#ifdef _PATH_DEFPATH
-# define DEFAULT_LOGIN_PATH _PATH_DEFPATH
-#else
-# define DEFAULT_LOGIN_PATH ":/usr/ucb:/bin:/usr/bin"
-#endif
+#define DEFAULT_LOGIN_PATH "/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin"
 
 /* The default PATH for simulated logins to superuser accounts.  */
-#ifdef _PATH_DEFPATH_ROOT
-# define DEFAULT_ROOT_LOGIN_PATH _PATH_DEFPATH_ROOT
-#else
-# define DEFAULT_ROOT_LOGIN_PATH "/usr/ucb:/bin:/usr/bin:/etc"
-#endif
+#define DEFAULT_ROOT_LOGIN_PATH "/usr/sbin:/bin:/usr/bin:/sbin:/usr/X11R6/bin"
 
 /* The shell to run if none is given in the user's passwd entry.  */
 #define DEFAULT_SHELL "/bin/sh"
@@ -119,7 +129,9 @@
 /* The user to become if none is specified.  */
 #define DEFAULT_USER "root"
 
+#ifndef USE_PAM
 char *crypt ();
+#endif
 char *getusershell ();
 void endusershell ();
 void setusershell ();
@@ -216,7 +228,26 @@
 }
 #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(a) \
+  if (retval) \
+    { \
+      pam_end (pamh, PAM_SUCCESS); \
+      a; \
+    }
+#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.  */
@@ -224,10 +255,49 @@
 static bool
 correct_password (const struct passwd *pw)
 {
+#ifdef USE_PAM
+  const struct passwd *lpw;
+  const char *cp;
+
+  retval = pam_start ("su", pw->pw_name, &conv, &pamh);
+  PAM_BAIL_P (return false);
+
+  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);
+      PAM_BAIL_P (return false);
+    }
+  cp = getlogin ();
+  if (!(cp && *cp && (lpw = getpwnam (cp)) != NULL && lpw->pw_uid == getuid ()))
+    lpw = getpwuid (getuid ());
+  if (lpw)
+    {
+      retval = pam_set_item (pamh, PAM_RUSER, (const void *) lpw->pw_name);
+      PAM_BAIL_P (return false);
+    }
+  retval = pam_authenticate (pamh, 0);
+  PAM_BAIL_P (return false);
+  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 (return false);
+    }
+  PAM_BAIL_P (return false);
+  /* must be authenticated if this point was reached */
+  return true;
+#else /* !USE_PAM */
   char *unencrypted, *encrypted, *correct;
 #if HAVE_GETSPNAM && HAVE_STRUCT_SPWD_SP_PWDP
   /* Shadow passwd stuff for SVR3 and maybe other systems.  */
-  struct spwd *sp = getspnam (pw->pw_name);
+  const struct spwd *sp = getspnam (pw->pw_name);
 
   endspent ();
   if (sp)
@@ -248,6 +318,7 @@
   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
@@ -272,8 +343,8 @@
       xsetenv ("USER", pw->pw_name);
       xsetenv ("LOGNAME", pw->pw_name);
       xsetenv ("PATH", (pw->pw_uid
-			? DEFAULT_LOGIN_PATH
-			: DEFAULT_ROOT_LOGIN_PATH));
+			? getdef_str ("PATH", DEFAULT_LOGIN_PATH)
+			: getdef_str ("SUPATH", DEFAULT_ROOT_LOGIN_PATH)));
     }
   else
     {
@@ -283,6 +354,12 @@
 	{
 	  xsetenv ("HOME", pw->pw_dir);
 	  xsetenv ("SHELL", shell);
+	  if (getdef_bool ("ALWAYS_SET_PATH", 0))
+	    xsetenv ("PATH", (pw->pw_uid
+			      ? getdef_str ("PATH",
+					    DEFAULT_LOGIN_PATH)
+			      : getdef_str ("SUPATH",
+					    DEFAULT_ROOT_LOGIN_PATH)));
 	  if (pw->pw_uid)
 	    {
 	      xsetenv ("USER", pw->pw_name);
@@ -303,12 +380,35 @@
     error (EXIT_FAIL, errno, _("cannot set groups"));
   endgrent ();
 #endif
+#ifdef USE_PAM
+  retval = pam_setcred (pamh, PAM_ESTABLISH_CRED);
+  if (retval != PAM_SUCCESS)
+    error (EXIT_FAIL, 0, "%s", pam_strerror (pamh, retval));
+
+  retval = pam_open_session (pamh,0);
+  if (retval != PAM_SUCCESS)
+    {
+       pam_setcred (pamh, PAM_DELETE_CRED);
+       error (EXIT_FAIL, 0, "could not open session: %s",
+              pam_strerror (pamh, retval));
+    }
+#endif /* USE_PAM */
   if (setgid (pw->pw_gid))
     error (EXIT_FAIL, errno, _("cannot set group id"));
   if (setuid (pw->pw_uid))
     error (EXIT_FAIL, errno, _("cannot set user id"));
 }
 
+#ifdef USE_PAM
+static bool caught = false;
+/* Signal handler for parent process later */
+static void
+su_catch_sig (int sig)
+{
+  caught = true;
+}
+#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
@@ -321,6 +421,88 @@
   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
+  pid_t child;
+  sigset_t ourset;
+  int status;
+
+  child = fork ();
+  if (child == (pid_t) -1)
+    error (EXIT_FAILURE, errno, "cannot fork");
+
+  if (child != 0)
+    {
+      /* parent only */
+      sigfillset (&ourset);
+      if (sigprocmask (SIG_BLOCK, &ourset, NULL))
+	{
+	  error (0, errno, "cannot block signals");
+	  caught = true;
+	}
+      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))
+	    {
+	      error (0, errno, "cannot set signal handler");
+	      caught = true;
+	    }
+	}
+      if (!caught)
+	{
+	  for (;;)
+	    {
+	      pid_t pid;
+
+	      pid = waitpid (child, &status, WUNTRACED);
+
+	      if (WIFSTOPPED (status))
+		{
+		  kill (getpid (), SIGSTOP);
+		  /* once we get here, we must have resumed */
+		  kill (pid, SIGCONT);
+		}
+	      else
+		break;
+	    }
+	  if (WIFSIGNALED (status))
+	    status = WTERMSIG (status) + 128;
+	  else
+	    status = WEXITSTATUS (status);
+	}
+      else
+	status = 1;
+
+      if (caught)
+	{
+	  fprintf (stderr, "\nSession terminated, killing shell...");
+	  kill (child, SIGTERM);
+	}
+      retval = pam_setcred (pamh, PAM_DELETE_CRED);
+      PAM_BAIL_P (exit (EXIT_FAILURE));
+      retval = pam_close_session (pamh, 0);
+      PAM_BAIL_P (exit (EXIT_FAILURE));
+      retval = pam_end (pamh, PAM_SUCCESS);
+      PAM_BAIL_P (exit (EXIT_FAILURE));
+      if (caught)
+	{
+	  sleep (2);
+	  kill (child, SIGKILL);
+	  fprintf (stderr, " ...killed.\n");
+	}
+      exit (status);
+    }
+
+  /* child shell */
+  pam_end (pamh, 0);
+#endif
 
   if (simulate_login)
     {
@@ -339,6 +521,11 @@
     args[argno++] = "-f";
   if (command)
     {
+      if (simulate_login)
+	/* Bash 2.0 have to be invoked as `-su'.  See the comments in
+	   `shell.c (run_startup_files)'.  */
+	args[0] = "-su";
+
       args[argno++] = "-c";
       args[argno++] = command;
     }
@@ -495,6 +682,9 @@
 #ifdef SYSLOG_FAILURE
       log_su (pw, false);
 #endif
+#ifdef USE_PAM
+      sleep (getdef_num ("FAIL_DELAY", 1));
+#endif
       error (EXIT_FAIL, 0, _("incorrect password"));
     }
 #ifdef SYSLOG_SUCCESS