Adding upstream version 1.5.2.upstream/1.5.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 875 insertions, 0 deletions

diff --git a/modules/pam_unix/pam_unix_passwd.c b/modules/pam_unix/pam_unix_passwd.c
new file mode 100644
index 0000000..a20e919
--- /dev/null
+++ b/modules/pam_unix/pam_unix_passwd.c
@@ -0,0 +1,875 @@
+/*
+ * pam_unix password management
+ *
+ * Main coding by Elliot Lee <sopwith@redhat.com>, Red Hat Software.
+ * Copyright (C) 1996.
+ * Copyright (c) Jan Rękorajski, 1999.
+ * Copyright (c) Red Hat, Inc., 2007, 2008.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, and the entire permission notice in its entirety,
+ *    including the disclaimer of warranties.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions.  (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <malloc.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <syslog.h>
+#include <shadow.h>
+#include <time.h>		/* for time() */
+#include <fcntl.h>
+#include <ctype.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+
+#include <signal.h>
+#include <sys/wait.h>
+#include <sys/resource.h>
+
+#include <security/_pam_macros.h>
+#include <security/pam_modules.h>
+#include <security/pam_ext.h>
+#include <security/pam_modutil.h>
+
+#include "pam_cc_compat.h"
+#include "md5.h"
+#include "support.h"
+#include "passverify.h"
+#include "bigcrypt.h"
+
+#if (HAVE_YP_GET_DEFAULT_DOMAIN || HAVE_GETDOMAINNAME) && HAVE_YP_MASTER
+# define HAVE_NIS
+#endif
+
+#ifdef HAVE_NIS
+# include <rpc/rpc.h>
+
+# if HAVE_RPCSVC_YP_PROT_H
+#  include <rpcsvc/yp_prot.h>
+# endif
+
+# if HAVE_RPCSVC_YPCLNT_H
+#  include <rpcsvc/ypclnt.h>
+# endif
+
+# include "yppasswd.h"
+
+# if !HAVE_DECL_GETRPCPORT &&!HAVE_RPCB_GETADDR
+extern int getrpcport(const char *host, unsigned long prognum,
+		      unsigned long versnum, unsigned int proto);
+# endif				/* GNU libc 2.1 */
+#endif
+
+/*
+   How it works:
+   Gets in username (has to be done) from the calling program
+   Does authentication of user (only if we are not running as root)
+   Gets new password/checks for sanity
+   Sets it.
+ */
+
+#define MAX_PASSWD_TRIES	3
+
+#ifdef HAVE_NIS
+#ifdef HAVE_RPCB_GETADDR
+static unsigned short
+__taddr2port (const struct netconfig *nconf, const struct netbuf *nbuf)
+{
+  unsigned short port = 0;
+  struct __rpc_sockinfo si;
+  struct sockaddr_in *sin;
+  struct sockaddr_in6 *sin6;
+  if (!__rpc_nconf2sockinfo(nconf, &si))
+    return 0;
+
+  switch (si.si_af)
+    {
+    case AF_INET:
+      sin = nbuf->buf;
+      port = sin->sin_port;
+      break;
+    case AF_INET6:
+      sin6 = nbuf->buf;
+      port = sin6->sin6_port;
+      break;
+    default:
+      break;
+    }
+
+  return htons (port);
+}
+#endif
+
+static char *getNISserver(pam_handle_t *pamh, unsigned long long ctrl)
+{
+	char *master;
+	char *domainname;
+	int port, err;
+#if defined(HAVE_RPCB_GETADDR)
+	struct netconfig *nconf;
+	struct netbuf svcaddr;
+	char addrbuf[INET6_ADDRSTRLEN];
+	void *handle;
+	int found;
+#endif
+
+
+#ifdef HAVE_YP_GET_DEFAULT_DOMAIN
+	if ((err = yp_get_default_domain(&domainname)) != 0) {
+		pam_syslog(pamh, LOG_WARNING, "can't get local yp domain: %s",
+			 yperr_string(err));
+		return NULL;
+	}
+#elif defined(HAVE_GETDOMAINNAME)
+	char domainname_res[256];
+
+	if (getdomainname (domainname_res, sizeof (domainname_res)) == 0)
+	  {
+	    if (strcmp (domainname_res, "(none)") == 0)
+	      {
+		/* If domainname is not set, some systems will return "(none)" */
+		domainname_res[0] = '\0';
+	      }
+	    domainname = domainname_res;
+	  }
+	else domainname = NULL;
+#endif
+
+	if ((err = yp_master(domainname, "passwd.byname", &master)) != 0) {
+		pam_syslog(pamh, LOG_WARNING, "can't find the master ypserver: %s",
+			 yperr_string(err));
+		return NULL;
+	}
+#ifdef HAVE_RPCB_GETADDR
+	svcaddr.len = 0;
+	svcaddr.maxlen = sizeof (addrbuf);
+	svcaddr.buf = addrbuf;
+	port = 0;
+	found = 0;
+
+	handle = setnetconfig();
+	while ((nconf = getnetconfig(handle)) != NULL) {
+	  if (!strcmp(nconf->nc_proto, "udp")) {
+	    if (rpcb_getaddr(YPPASSWDPROG, YPPASSWDPROC_UPDATE,
+			     nconf, &svcaddr, master)) {
+              port = __taddr2port (nconf, &svcaddr);
+              endnetconfig (handle);
+              found=1;
+              break;
+            }
+
+	    if (rpc_createerr.cf_stat != RPC_UNKNOWNHOST) {
+	      clnt_pcreateerror (master);
+              pam_syslog (pamh, LOG_ERR,
+			  "rpcb_getaddr (%s) failed!", master);
+              return NULL;
+            }
+	  }
+	}
+
+	if (!found) {
+	  pam_syslog (pamh, LOG_ERR,
+		      "Cannot find suitable transport for protocol 'udp'");
+	  return NULL;
+	}
+#else
+	port = getrpcport(master, YPPASSWDPROG, YPPASSWDPROC_UPDATE, IPPROTO_UDP);
+#endif
+	if (port == 0) {
+		pam_syslog(pamh, LOG_WARNING,
+		         "yppasswdd not running on NIS master host");
+		return NULL;
+	}
+	if (port >= IPPORT_RESERVED) {
+		pam_syslog(pamh, LOG_WARNING,
+		         "yppasswd daemon running on illegal port");
+		return NULL;
+	}
+	if (on(UNIX_DEBUG, ctrl)) {
+	  pam_syslog(pamh, LOG_DEBUG, "Use NIS server on %s with port %d",
+		     master, port);
+	}
+	return master;
+}
+#endif
+
+#ifdef WITH_SELINUX
+
+static int _unix_run_update_binary(pam_handle_t *pamh, unsigned long long ctrl, const char *user,
+    const char *fromwhat, const char *towhat, int remember)
+{
+    int retval, child, fds[2];
+    struct sigaction newsa, oldsa;
+
+    D(("called."));
+    /* create a pipe for the password */
+    if (pipe(fds) != 0) {
+	D(("could not make pipe"));
+	return PAM_AUTH_ERR;
+    }
+
+    if (off(UNIX_NOREAP, ctrl)) {
+	/*
+	 * This code arranges that the demise of the child does not cause
+	 * the application to receive a signal it is not expecting - which
+	 * may kill the application or worse.
+	 *
+	 * The "noreap" module argument is provided so that the admin can
+	 * override this behavior.
+	 */
+        memset(&newsa, '\0', sizeof(newsa));
+        newsa.sa_handler = SIG_DFL;
+        sigaction(SIGCHLD, &newsa, &oldsa);
+    }
+
+    /* fork */
+    child = fork();
+    if (child == 0) {
+	static char *envp[] = { NULL };
+	const char *args[] = { NULL, NULL, NULL, NULL, NULL, NULL };
+        char buffer[16];
+
+	/* XXX - should really tidy up PAM here too */
+
+	/* reopen stdin as pipe */
+	if (dup2(fds[0], STDIN_FILENO) != STDIN_FILENO) {
+		pam_syslog(pamh, LOG_ERR, "dup2 of %s failed: %m", "stdin");
+		_exit(PAM_AUTHINFO_UNAVAIL);
+	}
+
+	if (pam_modutil_sanitize_helper_fds(pamh, PAM_MODUTIL_IGNORE_FD,
+					    PAM_MODUTIL_PIPE_FD,
+					    PAM_MODUTIL_PIPE_FD) < 0) {
+		_exit(PAM_AUTHINFO_UNAVAIL);
+	}
+
+	/* exec binary helper */
+	args[0] = UPDATE_HELPER;
+	args[1] = user;
+	args[2] = "update";
+	if (on(UNIX_SHADOW, ctrl))
+		args[3] = "1";
+	else
+		args[3] = "0";
+
+        snprintf(buffer, sizeof(buffer), "%d", remember);
+        args[4] = buffer;
+
+	DIAG_PUSH_IGNORE_CAST_QUAL;
+	execve(UPDATE_HELPER, (char *const *) args, envp);
+	DIAG_POP_IGNORE_CAST_QUAL;
+
+	/* should not get here: exit with error */
+	D(("helper binary is not available"));
+	_exit(PAM_AUTHINFO_UNAVAIL);
+    } else if (child > 0) {
+	/* wait for child */
+	/* if the stored password is NULL */
+        int rc=0;
+	if (fromwhat) {
+	    int len = strlen(fromwhat);
+
+	    if (len > PAM_MAX_RESP_SIZE)
+	      len = PAM_MAX_RESP_SIZE;
+	    pam_modutil_write(fds[1], fromwhat, len);
+	}
+        pam_modutil_write(fds[1], "", 1);
+	if (towhat) {
+	    int len = strlen(towhat);
+
+	    if (len > PAM_MAX_RESP_SIZE)
+	      len = PAM_MAX_RESP_SIZE;
+	    pam_modutil_write(fds[1], towhat, len);
+        }
+        pam_modutil_write(fds[1], "", 1);
+
+	close(fds[0]);       /* close here to avoid possible SIGPIPE above */
+	close(fds[1]);
+	/* wait for helper to complete: */
+	while ((rc=waitpid(child, &retval, 0)) < 0 && errno == EINTR);
+	if (rc<0) {
+	  pam_syslog(pamh, LOG_ERR, "unix_update waitpid failed: %m");
+	  retval = PAM_AUTHTOK_ERR;
+	} else if (!WIFEXITED(retval)) {
+          pam_syslog(pamh, LOG_ERR, "unix_update abnormal exit: %d", retval);
+          retval = PAM_AUTHTOK_ERR;
+        } else {
+	  retval = WEXITSTATUS(retval);
+	}
+    } else {
+	D(("fork failed"));
+	close(fds[0]);
+	close(fds[1]);
+	retval = PAM_AUTH_ERR;
+    }
+
+    if (off(UNIX_NOREAP, ctrl)) {
+        sigaction(SIGCHLD, &oldsa, NULL);   /* restore old signal handler */
+    }
+
+    return retval;
+}
+#endif
+
+static int check_old_password(const char *forwho, const char *newpass)
+{
+	static char buf[16384];
+	char *s_pas;
+	int retval = PAM_SUCCESS;
+	FILE *opwfile;
+	size_t len = strlen(forwho);
+
+	opwfile = fopen(OLD_PASSWORDS_FILE, "r");
+	if (opwfile == NULL)
+		return PAM_ABORT;
+
+	while (fgets(buf, 16380, opwfile)) {
+		if (!strncmp(buf, forwho, len) && (buf[len] == ':' ||
+			buf[len] == ',')) {
+			char *sptr;
+			buf[strlen(buf) - 1] = '\0';
+			/* s_luser = */ strtok_r(buf, ":,", &sptr);
+			/* s_uid = */ strtok_r(NULL, ":,", &sptr);
+			/* s_npas = */ strtok_r(NULL, ":,", &sptr);
+			s_pas = strtok_r(NULL, ":,", &sptr);
+			while (s_pas != NULL) {
+				char *md5pass = Goodcrypt_md5(newpass, s_pas);
+				if (md5pass == NULL || !strcmp(md5pass, s_pas)) {
+					_pam_delete(md5pass);
+					retval = PAM_AUTHTOK_ERR;
+					break;
+				}
+				s_pas = strtok_r(NULL, ":,", &sptr);
+				_pam_delete(md5pass);
+			}
+			break;
+		}
+	}
+	fclose(opwfile);
+
+	return retval;
+}
+
+static int _do_setpass(pam_handle_t* pamh, const char *forwho,
+		       const char *fromwhat,
+		       char *towhat, unsigned long long ctrl, int remember)
+{
+	struct passwd *pwd = NULL;
+	int retval = 0;
+	int unlocked = 0;
+
+	D(("called"));
+
+	pwd = getpwnam(forwho);
+
+	if (pwd == NULL) {
+		retval = PAM_AUTHTOK_ERR;
+		goto done;
+	}
+
+	if (on(UNIX_NIS, ctrl) && _unix_comesfromsource(pamh, forwho, 0, 1)) {
+#ifdef HAVE_NIS
+	  char *master;
+
+	  if ((master=getNISserver(pamh, ctrl)) != NULL) {
+		struct timeval timeout;
+		struct yppasswd yppwd;
+		CLIENT *clnt;
+		int status;
+		enum clnt_stat err;
+
+		/* Unlock passwd file to avoid deadlock */
+		unlock_pwdf();
+		unlocked = 1;
+
+		/* Initialize password information */
+		yppwd.newpw.pw_passwd = pwd->pw_passwd;
+		yppwd.newpw.pw_name = pwd->pw_name;
+		yppwd.newpw.pw_uid = pwd->pw_uid;
+		yppwd.newpw.pw_gid = pwd->pw_gid;
+		yppwd.newpw.pw_gecos = pwd->pw_gecos;
+		yppwd.newpw.pw_dir = pwd->pw_dir;
+		yppwd.newpw.pw_shell = pwd->pw_shell;
+		yppwd.oldpass = fromwhat ? strdup (fromwhat) : strdup ("");
+		yppwd.newpw.pw_passwd = towhat;
+
+		D(("Set password %s for %s", yppwd.newpw.pw_passwd, forwho));
+
+		/* The yppasswd.x file said `unix authentication required',
+		 * so I added it. This is the only reason it is in here.
+		 * My yppasswdd doesn't use it, but maybe some others out there
+		 * do.                                        --okir
+		 */
+		clnt = clnt_create(master, YPPASSWDPROG, YPPASSWDVERS, "udp");
+		clnt->cl_auth = authunix_create_default();
+		memset((char *) &status, '\0', sizeof(status));
+		timeout.tv_sec = 25;
+		timeout.tv_usec = 0;
+		err = clnt_call(clnt, YPPASSWDPROC_UPDATE,
+				(xdrproc_t) xdr_yppasswd, (char *) &yppwd,
+				(xdrproc_t) xdr_int, (char *) &status,
+				timeout);
+
+		free (yppwd.oldpass);
+
+		if (err) {
+			_make_remark(pamh, ctrl, PAM_TEXT_INFO,
+				clnt_sperrno(err));
+		} else if (status) {
+			D(("Error while changing NIS password.\n"));
+		}
+		D(("The password has%s been changed on %s.",
+		   (err || status) ? " not" : "", master));
+		pam_syslog(pamh, LOG_NOTICE, "password%s changed for %s on %s",
+			 (err || status) ? " not" : "", pwd->pw_name, master);
+
+		auth_destroy(clnt->cl_auth);
+		clnt_destroy(clnt);
+		if (err || status) {
+			_make_remark(pamh, ctrl, PAM_TEXT_INFO,
+				_("NIS password could not be changed."));
+			retval = PAM_TRY_AGAIN;
+		}
+#ifdef PAM_DEBUG
+		sleep(5);
+#endif
+	    } else {
+		    retval = PAM_TRY_AGAIN;
+	    }
+#else
+          if (on(UNIX_DEBUG, ctrl)) {
+            pam_syslog(pamh, LOG_DEBUG, "No NIS support available");
+          }
+
+          retval = PAM_TRY_AGAIN;
+#endif
+	}
+
+	if (_unix_comesfromsource(pamh, forwho, 1, 0)) {
+		if(unlocked) {
+			if (lock_pwdf() != PAM_SUCCESS) {
+				return PAM_AUTHTOK_LOCK_BUSY;
+			}
+		}
+#ifdef WITH_SELINUX
+	        if (unix_selinux_confined())
+			  return _unix_run_update_binary(pamh, ctrl, forwho, fromwhat, towhat, remember);
+#endif
+		/* first, save old password */
+		if (save_old_password(pamh, forwho, fromwhat, remember)) {
+			retval = PAM_AUTHTOK_ERR;
+			goto done;
+		}
+		if (on(UNIX_SHADOW, ctrl) || is_pwd_shadowed(pwd)) {
+			retval = unix_update_shadow(pamh, forwho, towhat);
+			if (retval == PAM_SUCCESS)
+				if (!is_pwd_shadowed(pwd))
+					retval = unix_update_passwd(pamh, forwho, "x");
+		} else {
+			retval = unix_update_passwd(pamh, forwho, towhat);
+		}
+	}
+
+
+done:
+	unlock_pwdf();
+
+	return retval;
+}
+
+static int _unix_verify_shadow(pam_handle_t *pamh, const char *user, unsigned long long ctrl)
+{
+	struct passwd *pwent = NULL;	/* Password and shadow password */
+	struct spwd *spent = NULL;	/* file entries for the user */
+	int daysleft;
+	int retval;
+
+	retval = get_account_info(pamh, user, &pwent, &spent);
+	if (retval == PAM_USER_UNKNOWN) {
+		return retval;
+	}
+
+	if (retval == PAM_SUCCESS && spent == NULL)
+		return PAM_SUCCESS;
+
+	if (retval == PAM_UNIX_RUN_HELPER) {
+		retval = _unix_run_verify_binary(pamh, ctrl, user, &daysleft);
+		if (retval == PAM_AUTH_ERR || retval == PAM_USER_UNKNOWN)
+			return retval;
+	}
+	else if (retval == PAM_SUCCESS)
+		retval = check_shadow_expiry(pamh, spent, &daysleft);
+
+	if (on(UNIX__IAMROOT, ctrl) || retval == PAM_NEW_AUTHTOK_REQD)
+		return PAM_SUCCESS;
+
+	return retval;
+}
+
+static int _pam_unix_approve_pass(pam_handle_t * pamh
+				  ,unsigned long long ctrl
+				  ,const char *pass_old
+				  ,const char *pass_new,
+                                  int pass_min_len)
+{
+	const void *user;
+	const char *remark = NULL;
+	int retval = PAM_SUCCESS;
+
+	D(("&new=%p, &old=%p", pass_old, pass_new));
+	D(("new=[%s]", pass_new));
+	D(("old=[%s]", pass_old));
+
+	if (pass_new == NULL || (pass_old && !strcmp(pass_old, pass_new))) {
+		if (on(UNIX_DEBUG, ctrl)) {
+			pam_syslog(pamh, LOG_DEBUG, "bad authentication token");
+		}
+		_make_remark(pamh, ctrl, PAM_ERROR_MSG, pass_new == NULL ?
+			_("No password has been supplied.") :
+			_("The password has not been changed."));
+		return PAM_AUTHTOK_ERR;
+	}
+	/*
+	 * if one wanted to hardwire authentication token strength
+	 * checking this would be the place - AGM
+	 */
+
+	retval = pam_get_item(pamh, PAM_USER, &user);
+	if (retval != PAM_SUCCESS) {
+		if (on(UNIX_DEBUG, ctrl)) {
+			pam_syslog(pamh, LOG_ERR, "Can not get username");
+			return PAM_AUTHTOK_ERR;
+		}
+	}
+
+	if (strlen(pass_new) > PAM_MAX_RESP_SIZE) {
+		remark = _("You must choose a shorter password.");
+		D(("length exceeded [%s]", remark));
+	} else if (off(UNIX__IAMROOT, ctrl)) {
+		if ((int)strlen(pass_new) < pass_min_len)
+		  remark = _("You must choose a longer password.");
+		D(("length check [%s]", remark));
+		if (on(UNIX_REMEMBER_PASSWD, ctrl)) {
+			if ((retval = check_old_password(user, pass_new)) == PAM_AUTHTOK_ERR)
+			  remark = _("Password has been already used. Choose another.");
+			if (retval == PAM_ABORT) {
+				pam_syslog(pamh, LOG_ERR, "can't open %s file to check old passwords",
+					OLD_PASSWORDS_FILE);
+				return retval;
+			}
+		}
+	}
+	if (remark) {
+		_make_remark(pamh, ctrl, PAM_ERROR_MSG, remark);
+		retval = PAM_AUTHTOK_ERR;
+	}
+	return retval;
+}
+
+int
+pam_sm_chauthtok(pam_handle_t *pamh, int flags, int argc, const char **argv)
+{
+	unsigned long long ctrl, lctrl;
+	int retval;
+	int remember = -1;
+	int rounds = 0;
+	int pass_min_len = 0;
+
+	/* <DO NOT free() THESE> */
+	const char *user;
+	const void *item;
+	const char *pass_old, *pass_new;
+	/* </DO NOT free() THESE> */
+
+	D(("called."));
+
+	ctrl = _set_ctrl(pamh, flags, &remember, &rounds, &pass_min_len,
+	                 argc, argv);
+
+	/*
+	 * First get the name of a user
+	 */
+	retval = pam_get_user(pamh, &user, NULL);
+	if (retval == PAM_SUCCESS) {
+		/*
+		 * Various libraries at various times have had bugs related to
+		 * '+' or '-' as the first character of a user name. Don't
+		 * allow them.
+		 */
+		if (user[0] == '-' || user[0] == '+') {
+			pam_syslog(pamh, LOG_NOTICE, "bad username [%s]", user);
+			return PAM_USER_UNKNOWN;
+		}
+		if (retval == PAM_SUCCESS && on(UNIX_DEBUG, ctrl))
+			pam_syslog(pamh, LOG_DEBUG, "username [%s] obtained",
+			         user);
+	} else {
+		if (on(UNIX_DEBUG, ctrl))
+			pam_syslog(pamh, LOG_DEBUG,
+			         "password - could not identify user");
+		return retval;
+	}
+
+	D(("Got username of %s", user));
+
+	/*
+	 * Before we do anything else, check to make sure that the user's
+	 * info is in one of the databases we can modify from this module,
+	 * which currently is 'files' and 'nis'.  We have to do this because
+	 * getpwnam() doesn't tell you *where* the information it gives you
+	 * came from, nor should it.  That's our job.
+	 */
+	if (_unix_comesfromsource(pamh, user, 1, on(UNIX_NIS, ctrl)) == 0) {
+		pam_syslog(pamh, LOG_DEBUG,
+			 "user \"%s\" does not exist in /etc/passwd%s",
+			 user, on(UNIX_NIS, ctrl) ? " or NIS" : "");
+		return PAM_USER_UNKNOWN;
+	} else {
+		struct passwd *pwd;
+		_unix_getpwnam(pamh, user, 1, 1, &pwd);
+		if (pwd == NULL) {
+			pam_syslog(pamh, LOG_DEBUG,
+				"user \"%s\" has corrupted passwd entry",
+				user);
+			return PAM_USER_UNKNOWN;
+		}
+	}
+
+	/*
+	 * This is not an AUTH module!
+	 */
+	if (on(UNIX__NONULL, ctrl))
+		set(UNIX__NULLOK, ctrl);
+
+	if (on(UNIX__PRELIM, ctrl)) {
+		/*
+		 * obtain and verify the current password (OLDAUTHTOK) for
+		 * the user.
+		 */
+		D(("prelim check"));
+
+		if (_unix_blankpasswd(pamh, ctrl, user)) {
+			return PAM_SUCCESS;
+		} else if (off(UNIX__IAMROOT, ctrl) ||
+			   (on(UNIX_NIS, ctrl) && _unix_comesfromsource(pamh, user, 0, 1))) {
+			/* instruct user what is happening */
+			if (off(UNIX__QUIET, ctrl)) {
+				retval = pam_info(pamh, _("Changing password for %s."), user);
+				if (retval != PAM_SUCCESS)
+					return retval;
+			}
+			retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass_old, NULL);
+
+			if (retval != PAM_SUCCESS) {
+				pam_syslog(pamh, LOG_NOTICE,
+				    "password - (old) token not obtained");
+				return retval;
+			}
+			/* verify that this is the password for this user */
+
+			retval = _unix_verify_password(pamh, user, pass_old, ctrl);
+		} else {
+			D(("process run by root so do nothing this time around"));
+			pass_old = NULL;
+			retval = PAM_SUCCESS;	/* root doesn't have too */
+		}
+
+		if (retval != PAM_SUCCESS) {
+			D(("Authentication failed"));
+			pass_old = NULL;
+			return retval;
+		}
+		pass_old = NULL;
+		retval = _unix_verify_shadow(pamh,user, ctrl);
+		if (retval == PAM_AUTHTOK_ERR) {
+			if (off(UNIX__IAMROOT, ctrl))
+				_make_remark(pamh, ctrl, PAM_ERROR_MSG,
+					     _("You must wait longer to change your password."));
+			else
+				retval = PAM_SUCCESS;
+		}
+	} else if (on(UNIX__UPDATE, ctrl)) {
+		/*
+		 * tpass is used below to store the _pam_md() return; it
+		 * should be _pam_delete()'d.
+		 */
+
+		char *tpass = NULL;
+		int retry = 0;
+
+		/*
+		 * obtain the proposed password
+		 */
+
+		D(("do update"));
+
+		/*
+		 * get the old token back. NULL was ok only if root [at this
+		 * point we assume that this has already been enforced on a
+		 * previous call to this function].
+		 */
+
+		retval = pam_get_item(pamh, PAM_OLDAUTHTOK, &item);
+
+		if (retval != PAM_SUCCESS) {
+			pam_syslog(pamh, LOG_NOTICE, "user not authenticated");
+			return retval;
+		}
+		pass_old = item;
+		D(("pass_old [%s]", pass_old));
+
+		D(("get new password now"));
+
+		lctrl = ctrl;
+
+		if (on(UNIX_USE_AUTHTOK, lctrl)) {
+			set(UNIX_USE_FIRST_PASS, lctrl);
+		}
+		if (on(UNIX_USE_FIRST_PASS, lctrl)) {
+			retry = MAX_PASSWD_TRIES-1;
+		}
+		retval = PAM_AUTHTOK_ERR;
+		while ((retval != PAM_SUCCESS) && (retry++ < MAX_PASSWD_TRIES)) {
+			/*
+			 * use_authtok is to force the use of a previously entered
+			 * password -- needed for pluggable password strength checking
+			 */
+
+			retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass_new, NULL);
+
+			if (retval != PAM_SUCCESS) {
+				if (on(UNIX_DEBUG, ctrl)) {
+					pam_syslog(pamh, LOG_ERR,
+						 "password - new password not obtained");
+				}
+				pass_old = NULL;	/* tidy up */
+				return retval;
+			}
+			D(("returned to _unix_chauthtok"));
+
+			/*
+			 * At this point we know who the user is and what they
+			 * propose as their new password. Verify that the new
+			 * password is acceptable.
+			 */
+
+			if (*(const char *)pass_new == '\0') {	/* "\0" password = NULL */
+				pass_new = NULL;
+			}
+			retval = _pam_unix_approve_pass(pamh, ctrl, pass_old,
+			                                pass_new, pass_min_len);
+
+			if (retval != PAM_SUCCESS) {
+				pam_set_item(pamh, PAM_AUTHTOK, NULL);
+			}
+		}
+
+		if (retval != PAM_SUCCESS) {
+			pam_syslog(pamh, LOG_NOTICE,
+			         "new password not acceptable");
+			pass_new = pass_old = NULL;	/* tidy up */
+			return retval;
+		}
+		if (lock_pwdf() != PAM_SUCCESS) {
+			return PAM_AUTHTOK_LOCK_BUSY;
+		}
+
+		if (pass_old) {
+			retval = _unix_verify_password(pamh, user, pass_old, ctrl);
+			if (retval != PAM_SUCCESS) {
+				pam_syslog(pamh, LOG_NOTICE, "user password changed by another process");
+				unlock_pwdf();
+				return retval;
+			}
+		}
+
+		retval = _unix_verify_shadow(pamh, user, ctrl);
+		if (retval != PAM_SUCCESS) {
+			pam_syslog(pamh, LOG_NOTICE, "user shadow entry expired");
+			unlock_pwdf();
+			return retval;
+		}
+
+		retval = _pam_unix_approve_pass(pamh, ctrl, pass_old, pass_new,
+		                                pass_min_len);
+		if (retval != PAM_SUCCESS) {
+			pam_syslog(pamh, LOG_NOTICE,
+			         "new password not acceptable 2");
+			pass_new = pass_old = NULL;	/* tidy up */
+			unlock_pwdf();
+			return retval;
+		}
+
+		/*
+		 * By reaching here we have approved the passwords and must now
+		 * rebuild the password database file.
+		 */
+
+		/*
+		 * First we encrypt the new password.
+		 */
+
+		tpass = create_password_hash(pamh, pass_new, ctrl, rounds);
+		if (tpass == NULL) {
+			pam_syslog(pamh, LOG_CRIT,
+				"crypt() failure or out of memory for password");
+			pass_new = pass_old = NULL;	/* tidy up */
+			unlock_pwdf();
+			return PAM_BUF_ERR;
+		}
+
+		D(("password processed"));
+
+		/* update the password database(s) -- race conditions..? */
+
+		retval = _do_setpass(pamh, user, pass_old, tpass, ctrl,
+		                     remember);
+	        /* _do_setpass has called unlock_pwdf for us */
+
+		_pam_delete(tpass);
+		pass_old = pass_new = NULL;
+	} else {		/* something has broken with the module */
+		pam_syslog(pamh, LOG_CRIT,
+		         "password received unknown request");
+		retval = PAM_ABORT;
+	}
+
+	D(("retval was %d", retval));
+
+	return retval;
+}