Add xauth-pam, an XAuth backend verifying credentials with PAM

7 files changed, 395 insertions, 1 deletions

diff --git a/configure.in b/configure.in
index c5fd1d3c6..a1adb8cc1 100644
--- a/configure.in
+++ b/configure.in
@@ -134,6 +134,7 @@ ARG_ENABL_SET([eap-tnc],        [enable EAP TNC trusted network connect module.]
 ARG_ENABL_SET([eap-radius],     [enable RADIUS proxy authentication module.])
 ARG_DISBL_SET([xauth-generic],  [disable generic XAuth backend.])
 ARG_ENABL_SET([xauth-eap],      [enable XAuth backend using EAP methods to verify passwords.])
+ARG_ENABL_SET([xauth-pam],      [enable XAuth backend using PAM to verify passwords.])
 ARG_ENABL_SET([tnc-ifmap],      [enable TNC IF-MAP module.])
 ARG_ENABL_SET([tnc-pdp],        [enable TNC policy decision point module.])
 ARG_ENABL_SET([tnc-imc],        [enable TNC IMC module.])
@@ -745,7 +746,7 @@ if test x$nm = xtrue; then
 	AC_SUBST(nm_LIBS)
 fi
 
-if test x$eap_gtc = xtrue; then
+if test x$xauth_pam = xtrue; then
 	AC_HAVE_LIBRARY([pam],[LIBS="$LIBS"],[AC_MSG_ERROR([PAM library not found])])
 	AC_CHECK_HEADER([security/pam_appl.h],,[AC_MSG_ERROR([PAM header security/pam_appl.h not found!])])
 fi
@@ -900,6 +901,7 @@ ADD_PLUGIN([eap-peap],             [c charon nm])
 ADD_PLUGIN([eap-tnc],              [c charon])
 ADD_PLUGIN([xauth-generic],        [c charon])
 ADD_PLUGIN([xauth-eap],            [c charon])
+ADD_PLUGIN([xauth-pam],            [c charon])
 ADD_PLUGIN([tnc-ifmap],            [c charon])
 ADD_PLUGIN([tnc-pdp],              [c charon])
 ADD_PLUGIN([tnc-imc],              [c charon])
@@ -1026,6 +1028,7 @@ AM_CONDITIONAL(USE_EAP_TNC, test x$eap_tnc = xtrue)
 AM_CONDITIONAL(USE_EAP_RADIUS, test x$eap_radius = xtrue)
 AM_CONDITIONAL(USE_XAUTH_GENERIC, test x$xauth_generic = xtrue)
 AM_CONDITIONAL(USE_XAUTH_EAP, test x$xauth_eap = xtrue)
+AM_CONDITIONAL(USE_XAUTH_PAM, test x$xauth_pam = xtrue)
 AM_CONDITIONAL(USE_TNC_IFMAP, test x$tnc_ifmap = xtrue)
 AM_CONDITIONAL(USE_TNC_PDP, test x$tnc_pdp = xtrue)
 AM_CONDITIONAL(USE_TNC_IMC, test x$tnc_imc = xtrue)
@@ -1204,6 +1207,7 @@ AC_OUTPUT(
 	src/libcharon/plugins/eap_radius/Makefile
 	src/libcharon/plugins/xauth_generic/Makefile
 	src/libcharon/plugins/xauth_eap/Makefile
+	src/libcharon/plugins/xauth_pam/Makefile
 	src/libcharon/plugins/tnc_ifmap/Makefile
 	src/libcharon/plugins/tnc_pdp/Makefile
 	src/libcharon/plugins/tnc_imc/Makefile
diff --git a/src/libcharon/Makefile.am b/src/libcharon/Makefile.am
index a254c0336..2d4227990 100644
--- a/src/libcharon/Makefile.am
+++ b/src/libcharon/Makefile.am
@@ -546,3 +546,10 @@ if MONOLITHIC
   libcharon_la_LIBADD += plugins/xauth_eap/libstrongswan-xauth-eap.la
 endif
 endif
+
+if USE_XAUTH_PAM
+  SUBDIRS += plugins/xauth_pam
+if MONOLITHIC
+  libcharon_la_LIBADD += plugins/xauth_pam/libstrongswan-xauth-pam.la
+endif
+endif
diff --git a/src/libcharon/plugins/xauth_pam/Makefile.am b/src/libcharon/plugins/xauth_pam/Makefile.am
new file mode 100644
index 000000000..47521a3ff
--- /dev/null
+++ b/src/libcharon/plugins/xauth_pam/Makefile.am
@@ -0,0 +1,17 @@
+
+INCLUDES = -I$(top_srcdir)/src/libstrongswan -I$(top_srcdir)/src/libhydra \
+	-I$(top_srcdir)/src/libcharon
+
+AM_CFLAGS = -rdynamic
+
+if MONOLITHIC
+noinst_LTLIBRARIES = libstrongswan-xauth-pam.la
+else
+plugin_LTLIBRARIES = libstrongswan-xauth-pam.la
+endif
+
+libstrongswan_xauth_pam_la_SOURCES = \
+	xauth_pam_plugin.h xauth_pam_plugin.c \
+	xauth_pam.h xauth_pam.c
+
+libstrongswan_xauth_pam_la_LDFLAGS = -module -avoid-version -lpam
diff --git a/src/libcharon/plugins/xauth_pam/xauth_pam.c b/src/libcharon/plugins/xauth_pam/xauth_pam.c
new file mode 100644
index 000000000..98c1a97a4
--- /dev/null
+++ b/src/libcharon/plugins/xauth_pam/xauth_pam.c
@@ -0,0 +1,215 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ *
+ * 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 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+#include "xauth_pam.h"
+
+#include <daemon.h>
+#include <library.h>
+
+#include <security/pam_appl.h>
+
+typedef struct private_xauth_pam_t private_xauth_pam_t;
+
+/**
+ * Private data of an xauth_pam_t object.
+ */
+struct private_xauth_pam_t {
+
+	/**
+	 * Public interface.
+	 */
+	xauth_pam_t public;
+
+	/**
+	 * ID of the peer
+	 */
+	identification_t *peer;
+};
+
+METHOD(xauth_method_t, initiate, status_t,
+	private_xauth_pam_t *this, cp_payload_t **out)
+{
+	cp_payload_t *cp;
+
+	cp = cp_payload_create_type(CONFIGURATION_V1, CFG_REQUEST);
+	cp->add_attribute(cp, configuration_attribute_create_chunk(
+				CONFIGURATION_ATTRIBUTE_V1, XAUTH_USER_NAME, chunk_empty));
+	cp->add_attribute(cp, configuration_attribute_create_chunk(
+				CONFIGURATION_ATTRIBUTE_V1, XAUTH_USER_PASSWORD, chunk_empty));
+	*out = cp;
+	return NEED_MORE;
+}
+
+/**
+ * PAM conv callback function
+ */
+static int auth_conv(int num_msg, const struct pam_message **msg,
+					 struct pam_response **resp, char *password)
+{
+	struct pam_response *response;
+
+	if (num_msg != 1)
+	{
+		return PAM_CONV_ERR;
+	}
+	response = malloc(sizeof(struct pam_response));
+	response->resp = strdup(password);
+	response->resp_retcode = 0;
+	*resp = response;
+	return PAM_SUCCESS;
+}
+
+/**
+ * Authenticate a username/password using PAM
+ */
+static bool authenticate(char *service, char *user, char *password)
+{
+	pam_handle_t *pamh = NULL;
+	static struct pam_conv conv;
+	int ret;
+
+	conv.conv = (void*)auth_conv;
+	conv.appdata_ptr = password;
+
+	ret = pam_start(service, user, &conv, &pamh);
+	if (ret != PAM_SUCCESS)
+	{
+		DBG1(DBG_IKE, "XAuth pam_start for '%s' failed: %s",
+			 user, pam_strerror(pamh, ret));
+		return FALSE;
+	}
+	ret = pam_authenticate(pamh, 0);
+	if (ret == PAM_SUCCESS)
+	{
+		ret = pam_acct_mgmt(pamh, 0);
+		if (ret != PAM_SUCCESS)
+		{
+			DBG1(DBG_IKE, "XAuth pam_acct_mgmt for '%s' failed: %s",
+				 user, pam_strerror(pamh, ret));
+		}
+	}
+	else
+	{
+		DBG1(DBG_IKE, "XAuth pam_authenticate for '%s' failed: %s",
+			 user, pam_strerror(pamh, ret));
+	}
+	pam_end(pamh, ret);
+	return ret == PAM_SUCCESS;
+}
+
+/**
+ * Convert configuration attribute content to a null-terminated string
+ */
+static void attr2string(char *buf, size_t len, chunk_t chunk)
+{
+	if (chunk.len && chunk.len < len)
+	{
+		snprintf(buf, len, "%.*s", (int)chunk.len, chunk.ptr);
+	}
+}
+
+METHOD(xauth_method_t, process, status_t,
+	private_xauth_pam_t *this, cp_payload_t *in, cp_payload_t **out)
+{
+	char *service, user[128] = "", pass[128] = "", *pos;
+	configuration_attribute_t *attr;
+	enumerator_t *enumerator;
+	chunk_t chunk;
+
+	enumerator = in->create_attribute_enumerator(in);
+	while (enumerator->enumerate(enumerator, &attr))
+	{
+		switch (attr->get_type(attr))
+		{
+			case XAUTH_USER_NAME:
+				/* trim to username part if email address given */
+				chunk = attr->get_chunk(attr);
+				pos = memchr(chunk.ptr, '@', chunk.len);
+				if (pos)
+				{
+					chunk.len = (u_char*)pos - chunk.ptr;
+				}
+				attr2string(user, sizeof(user), chunk);
+				break;
+			case XAUTH_USER_PASSWORD:
+				attr2string(pass, sizeof(pass), attr->get_chunk(attr));
+				break;
+			default:
+				break;
+		}
+	}
+	enumerator->destroy(enumerator);
+
+	if (!user[0] || !pass[0])
+	{
+		DBG1(DBG_IKE, "peer did not respond to our XAuth request");
+		return FAILED;
+	}
+
+	this->peer->destroy(this->peer);
+	this->peer = identification_create_from_string(user);
+
+	/* Look for PAM service, with a legacy fallback for the eap-gtc plugin.
+	 * Default to "login". */
+	service = lib->settings->get_str(lib->settings,
+				"%s.plugins.xauth-pam.pam_service",
+					lib->settings->get_str(lib->settings,
+						"%s.plugins.eap-gtc.pam_service",
+						"login", charon->name),
+				charon->name);
+
+	if (authenticate(service, user, pass))
+	{
+		DBG1(DBG_IKE, "PAM authentication of '%s' successful", user);
+		return SUCCESS;
+	}
+	return FAILED;
+}
+
+METHOD(xauth_method_t, get_identity, identification_t*,
+	private_xauth_pam_t *this)
+{
+	return this->peer;
+}
+
+METHOD(xauth_method_t, destroy, void,
+	private_xauth_pam_t *this)
+{
+	this->peer->destroy(this->peer);
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+xauth_pam_t *xauth_pam_create_server(identification_t *server,
+									 identification_t *peer)
+{
+	private_xauth_pam_t *this;
+
+	INIT(this,
+		.public = {
+			.xauth_method = {
+				.initiate = _initiate,
+				.process = _process,
+				.get_identity = _get_identity,
+				.destroy = _destroy,
+			},
+		},
+		.peer = peer->clone(peer),
+	);
+
+	return &this->public;
+}
diff --git a/src/libcharon/plugins/xauth_pam/xauth_pam.h b/src/libcharon/plugins/xauth_pam/xauth_pam.h
new file mode 100644
index 000000000..f2d310c0d
--- /dev/null
+++ b/src/libcharon/plugins/xauth_pam/xauth_pam.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ *
+ * 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 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup xauth_pam_i xauth_pam
+ * @{ @ingroup xauth_pam
+ */
+
+#ifndef XAUTH_PAM_H_
+#define XAUTH_PAM_H_
+
+typedef struct xauth_pam_t xauth_pam_t;
+
+#include <sa/xauth/xauth_method.h>
+
+/**
+ * XAuth plugin using Pluggable Authentication Modules to verify credentials.
+ */
+struct xauth_pam_t {
+
+	/**
+	 * Implemented xauth_method_t interface.
+	 */
+	xauth_method_t xauth_method;
+};
+
+/**
+ * Creates the XAuth method using PAM, acting as server.
+ *
+ * @param server	ID of the XAuth server
+ * @param peer		ID of the XAuth client
+ * @return			xauth_pam_t object
+ */
+xauth_pam_t *xauth_pam_create_server(identification_t *server,
+									 identification_t *peer);
+
+#endif /** XAUTH_PAM_H_ @}*/
diff --git a/src/libcharon/plugins/xauth_pam/xauth_pam_plugin.c b/src/libcharon/plugins/xauth_pam/xauth_pam_plugin.c
new file mode 100644
index 000000000..363aaf003
--- /dev/null
+++ b/src/libcharon/plugins/xauth_pam/xauth_pam_plugin.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ *
+ * 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 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+#include "xauth_pam_plugin.h"
+#include "xauth_pam.h"
+
+#include <daemon.h>
+
+METHOD(plugin_t, get_name, char*,
+	xauth_pam_plugin_t *this)
+{
+	return "xauth-pam";
+}
+
+METHOD(plugin_t, get_features, int,
+	xauth_pam_plugin_t *this, plugin_feature_t *features[])
+{
+	static plugin_feature_t f[] = {
+		PLUGIN_CALLBACK(xauth_method_register, xauth_pam_create_server),
+			PLUGIN_PROVIDE(XAUTH_SERVER, "pam"),
+	};
+	*features = f;
+	return countof(f);
+}
+
+METHOD(plugin_t, destroy, void,
+	xauth_pam_plugin_t *this)
+{
+	free(this);
+}
+
+/*
+ * see header file
+ */
+plugin_t *xauth_pam_plugin_create()
+{
+	xauth_pam_plugin_t *this;
+
+	INIT(this,
+		.plugin = {
+			.get_name = _get_name,
+			.get_features = _get_features,
+			.destroy = _destroy,
+		},
+	);
+
+	return &this->plugin;
+}
diff --git a/src/libcharon/plugins/xauth_pam/xauth_pam_plugin.h b/src/libcharon/plugins/xauth_pam/xauth_pam_plugin.h
new file mode 100644
index 000000000..b75268880
--- /dev/null
+++ b/src/libcharon/plugins/xauth_pam/xauth_pam_plugin.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ *
+ * 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 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup xauth_pam xauth_pam
+ * @ingroup cplugins
+ *
+ * @defgroup xauth_pam_plugin xauth_pam_plugin
+ * @{ @ingroup xauth_pam
+ */
+
+#ifndef XAUTH_PAM_PLUGIN_H_
+#define XAUTH_PAM_PLUGIN_H_
+
+#include <plugins/plugin.h>
+
+typedef struct xauth_pam_plugin_t xauth_pam_plugin_t;
+
+/**
+ * XAuth plugin using Pluggable Authentication Modules to verify credentials.
+ */
+struct xauth_pam_plugin_t {
+
+	/**
+	 * implements plugin interface
+	 */
+	plugin_t plugin;
+};
+
+#endif /** XAUTH_PAM_PLUGIN_H_ @}*/