Implemented permanent certificate coupling plugin
authorMartin Willi <martin@revosec.ch>
Mon, 21 Feb 2011 13:05:21 +0000 (13:05 +0000)
committerMartin Willi <martin@revosec.ch>
Mon, 28 Feb 2011 15:39:40 +0000 (16:39 +0100)
configure.in
src/libcharon/Makefile.am
src/libcharon/plugins/coupling/Makefile.am [new file with mode: 0644]
src/libcharon/plugins/coupling/coupling_plugin.c [new file with mode: 0644]
src/libcharon/plugins/coupling/coupling_plugin.h [new file with mode: 0644]
src/libcharon/plugins/coupling/coupling_validator.c [new file with mode: 0644]
src/libcharon/plugins/coupling/coupling_validator.h [new file with mode: 0644]

index 938afb0..009af12 100644 (file)
@@ -169,6 +169,7 @@ ARG_ENABL_SET([ha],             [enable high availability cluster plugin.])
 ARG_ENABL_SET([whitelist],      [enable peer identity whitelisting plugin.])
 ARG_ENABL_SET([led],            [enable plugin to control LEDs on IKEv2 activity using the Linux kernel LED subsystem.])
 ARG_ENABL_SET([duplicheck],     [advanced duplicate checking plugin using liveness checks.])
+ARG_ENABL_SET([coupling],       [enable IKEv2 plugin to couple peer certificates permanently to authentication.])
 ARG_ENABL_SET([vstr],           [enforce using the Vstr string library to replace glibc-like printf hooks.])
 ARG_ENABL_SET([monolithic],     [build monolithic version of libstrongswan that includes all enabled plugins. Similarly, the plugins of charon are assembled in libcharon.])
 
@@ -779,6 +780,7 @@ ADD_PLUGIN([ha],                   [c libcharon])
 ADD_PLUGIN([whitelist],            [c libcharon])
 ADD_PLUGIN([led],                  [c libcharon])
 ADD_PLUGIN([duplicheck],           [c libcharon])
+ADD_PLUGIN([coupling],             [c libcharon])
 ADD_PLUGIN([maemo],                [c libcharon])
 ADD_PLUGIN([uci],                  [c libcharon])
 ADD_PLUGIN([addrblock],            [c libcharon])
@@ -860,6 +862,7 @@ AM_CONDITIONAL(USE_HA, test x$ha = xtrue)
 AM_CONDITIONAL(USE_WHITELIST, test x$whitelist = xtrue)
 AM_CONDITIONAL(USE_LED, test x$led = xtrue)
 AM_CONDITIONAL(USE_DUPLICHECK, test x$duplicheck = xtrue)
+AM_CONDITIONAL(USE_COUPLING, test x$coupling = xtrue)
 AM_CONDITIONAL(USE_EAP_SIM, test x$eap_sim = xtrue)
 AM_CONDITIONAL(USE_EAP_SIM_FILE, test x$eap_sim_file = xtrue)
 AM_CONDITIONAL(USE_EAP_SIMAKA_SQL, test x$eap_simaka_sql = xtrue)
@@ -1043,6 +1046,7 @@ AC_OUTPUT(
        src/libcharon/plugins/whitelist/Makefile
        src/libcharon/plugins/led/Makefile
        src/libcharon/plugins/duplicheck/Makefile
+       src/libcharon/plugins/coupling/Makefile
        src/libcharon/plugins/android/Makefile
        src/libcharon/plugins/maemo/Makefile
        src/libcharon/plugins/stroke/Makefile
index 8a4f891..a995cae 100644 (file)
@@ -424,6 +424,13 @@ if MONOLITHIC
 endif
 endif
 
+if USE_COUPLING
+  SUBDIRS += plugins/coupling
+if MONOLITHIC
+  libcharon_la_LIBADD += plugins/coupling/libstrongswan-coupling.la
+endif
+endif
+
 if USE_UCI
   SUBDIRS += plugins/uci
 if MONOLITHIC
diff --git a/src/libcharon/plugins/coupling/Makefile.am b/src/libcharon/plugins/coupling/Makefile.am
new file mode 100644 (file)
index 0000000..642ce82
--- /dev/null
@@ -0,0 +1,16 @@
+
+INCLUDES = -I$(top_srcdir)/src/libstrongswan -I$(top_srcdir)/src/libhydra \
+       -I$(top_srcdir)/src/libcharon
+
+AM_CFLAGS = -rdynamic
+
+if MONOLITHIC
+noinst_LTLIBRARIES = libstrongswan-coupling.la
+else
+plugin_LTLIBRARIES = libstrongswan-coupling.la
+endif
+
+libstrongswan_coupling_la_SOURCES = coupling_plugin.h coupling_plugin.c \
+       coupling_validator.h coupling_validator.c
+
+libstrongswan_coupling_la_LDFLAGS = -module -avoid-version
diff --git a/src/libcharon/plugins/coupling/coupling_plugin.c b/src/libcharon/plugins/coupling/coupling_plugin.c
new file mode 100644 (file)
index 0000000..8e0705c
--- /dev/null
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2011 Martin Willi
+ * Copyright (C) 2011 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 "coupling_plugin.h"
+
+#include "coupling_validator.h"
+
+#include <daemon.h>
+
+typedef struct private_coupling_plugin_t private_coupling_plugin_t;
+
+/**
+ * private data of coupling plugin
+ */
+struct private_coupling_plugin_t {
+
+       /**
+        * implements plugin interface
+        */
+       coupling_plugin_t public;
+
+       /**
+        * validator controlling couplings
+        */
+       coupling_validator_t *validator;
+};
+
+METHOD(plugin_t, destroy, void,
+       private_coupling_plugin_t *this)
+{
+       lib->credmgr->remove_validator(lib->credmgr, &this->validator->validator);
+       this->validator->destroy(this->validator);
+       free(this);
+}
+
+/**
+ * Plugin constructor
+ */
+plugin_t *coupling_plugin_create()
+{
+       private_coupling_plugin_t *this;
+
+       INIT(this,
+               .public = {
+                       .plugin = {
+                               .destroy = _destroy,
+                       },
+               },
+               .validator = coupling_validator_create(),
+       );
+
+       if (!this->validator)
+       {
+               free(this);
+               return NULL;
+       }
+
+       lib->credmgr->add_validator(lib->credmgr, &this->validator->validator);
+
+       return &this->public.plugin;
+}
diff --git a/src/libcharon/plugins/coupling/coupling_plugin.h b/src/libcharon/plugins/coupling/coupling_plugin.h
new file mode 100644 (file)
index 0000000..645100b
--- /dev/null
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2011 Martin Willi
+ * Copyright (C) 2011 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 coupling coupling
+ * @ingroup cplugins
+ *
+ * @defgroup coupling_plugin coupling_plugin
+ * @{ @ingroup coupling
+ */
+
+#ifndef COUPLING_PLUGIN_H_
+#define COUPLING_PLUGIN_H_
+
+#include <plugins/plugin.h>
+
+typedef struct coupling_plugin_t coupling_plugin_t;
+
+/**
+ * Plugin to couple peer certificates permanently to peer authentication.
+ */
+struct coupling_plugin_t {
+
+       /**
+        * implements plugin interface
+        */
+       plugin_t plugin;
+};
+
+#endif /** COUPLING_PLUGIN_H_ @}*/
diff --git a/src/libcharon/plugins/coupling/coupling_validator.c b/src/libcharon/plugins/coupling/coupling_validator.c
new file mode 100644 (file)
index 0000000..06b6f7d
--- /dev/null
@@ -0,0 +1,258 @@
+/*
+ * Copyright (C) 2011 Martin Willi
+ * Copyright (C) 2011 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 "coupling_validator.h"
+
+#include <errno.h>
+#include <time.h>
+
+#include <daemon.h>
+#include <threading/mutex.h>
+
+/* buffer size for hex-encoded hash */
+#define MAX_HASH_SIZE (HASH_SIZE_SHA512 * 2 + 1)
+
+typedef struct private_coupling_validator_t private_coupling_validator_t;
+
+/**
+ * Private data of an coupling_validator_t object.
+ */
+struct private_coupling_validator_t {
+
+       /**
+        * Public coupling_validator_t interface.
+        */
+       coupling_validator_t public;
+
+       /**
+        * Mutex
+        */
+       mutex_t *mutex;
+
+       /**
+        * File with device couplings
+        */
+       FILE *f;
+
+       /**
+        * Hasher to create hashes
+        */
+       hasher_t *hasher;
+
+       /**
+        * maximum number of couplings
+        */
+       int max_couplings;
+};
+
+/**
+ * Get hash of a certificate
+ */
+static bool get_cert_hash(private_coupling_validator_t *this,
+                                                 certificate_t *cert, char *hex)
+{
+       char buf[MAX_HASH_SIZE];
+       chunk_t encoding;
+
+       if (!cert->get_encoding(cert, CERT_ASN1_DER, &encoding))
+       {
+               return FALSE;
+       }
+       this->hasher->get_hash(this->hasher, encoding, buf);
+       free(encoding.ptr);
+       chunk_to_hex(chunk_create(buf, this->hasher->get_hash_size(this->hasher)),
+                                hex, FALSE);
+       return TRUE;
+}
+
+/**
+ * Check if we have an entry for a given hash
+ */
+static bool has_entry(private_coupling_validator_t *this, char *hash)
+{
+       char line[256];
+       int hash_len;
+
+       hash_len = strlen(hash);
+       rewind(this->f);
+
+       while (fgets(line, sizeof(line), this->f))
+       {
+               if (strlen(line) >= hash_len &&
+                       strncaseeq(line, hash, hash_len))
+               {
+                       return TRUE;
+               }
+       }
+       return FALSE;
+}
+
+/**
+ * Get the number of coupling entries we currently have
+ */
+static int get_number_of_entries(private_coupling_validator_t *this)
+{
+       char line[256];
+       int count = 0;
+
+       rewind(this->f);
+
+       while (fgets(line, sizeof(line), this->f))
+       {
+               /* valid entries start with hex encoded hash */
+               if (strchr("1234567890abcdefABCDEF", line[0]))
+               {
+                       count++;
+               }
+       }
+       return count;
+}
+
+/**
+ * Add a new entry to the file
+ */
+static bool add_entry(private_coupling_validator_t *this, char *hash,
+                                         identification_t *id)
+{
+       return fseek(this->f, 0, SEEK_END) == 0 &&
+                  fprintf(this->f, "%s %u '%Y'\n", hash, time(NULL), id) > 0;
+}
+
+METHOD(cert_validator_t, validate, bool,
+       private_coupling_validator_t *this,
+       certificate_t *subject, certificate_t *issuer,
+       bool online, u_int pathlen, bool anchor, auth_cfg_t *auth)
+{
+       bool valid = FALSE;
+       char hash[MAX_HASH_SIZE];
+
+       if (pathlen != 0)
+       {
+               return TRUE;
+       }
+       if (get_cert_hash(this, subject, hash))
+       {
+               this->mutex->lock(this->mutex);
+               if (has_entry(this, hash))
+               {
+                       DBG1(DBG_CFG, "coupled certificate '%Y' found, accepted",
+                                subject->get_subject(subject));
+                       valid = TRUE;
+               }
+               else if (get_number_of_entries(this) < this->max_couplings)
+               {
+                       if (add_entry(this, hash, subject->get_subject(subject)))
+                       {
+                               DBG1(DBG_CFG, "coupled new certificate '%Y'",
+                                        subject->get_subject(subject));
+                               valid = TRUE;
+                       }
+                       else
+                       {
+                               DBG1(DBG_CFG, "coupling new certificate '%Y' failed",
+                                        subject->get_subject(subject));
+                       }
+               }
+               else
+               {
+                       DBG1(DBG_CFG, "coupling new certificate '%Y' failed, limit of %d "
+                                "couplings reached", subject->get_subject(subject),
+                                this->max_couplings);
+               }
+               this->mutex->unlock(this->mutex);
+       }
+       return valid;
+}
+
+METHOD(coupling_validator_t, destroy, void,
+       private_coupling_validator_t *this)
+{
+       if (this->f)
+       {
+               fclose(this->f);
+       }
+       DESTROY_IF(this->hasher);
+       this->mutex->destroy(this->mutex);
+       free(this);
+}
+
+/**
+ * See header
+ */
+coupling_validator_t *coupling_validator_create()
+{
+       private_coupling_validator_t *this;
+       char *path, *hash;
+       int i;
+       struct {
+               hash_algorithm_t alg;
+               char *name;
+       } hash_types[] = {
+               { HASH_MD5,             "md5"},
+               { HASH_SHA1,    "sha1"},
+               { HASH_SHA256,  "sha256"},
+               { HASH_SHA384,  "sha384"},
+               { HASH_SHA512,  "sha512"},
+       };
+
+       INIT(this,
+               .public = {
+                       .validator = {
+                               .validate = _validate,
+                       },
+                       .destroy = _destroy,
+               },
+               .mutex = mutex_create(MUTEX_TYPE_DEFAULT),
+               .max_couplings = lib->settings->get_int(lib->settings,
+                                                                         "charon.plugins.coupling.max", 1),
+       );
+
+       hash = lib->settings->get_str(lib->settings,
+                                                                 "charon.plugins.coupling.hash", "sha1");
+       for (i = 0; i < countof(hash_types); i++)
+       {
+               if (strcaseeq(hash_types[i].name, hash))
+               {
+                       this->hasher = lib->crypto->create_hasher(lib->crypto,
+                                                                                                         hash_types[i].alg);
+                       break;
+               }
+       }
+       if (!this->hasher)
+       {
+               DBG1(DBG_CFG, "unsupported coupling hash algorithm: %s", hash);
+               destroy(this);
+               return NULL;
+       }
+
+       path = lib->settings->get_str(lib->settings,
+                                                                 "charon.plugins.coupling.file", NULL);
+       if (!path)
+       {
+               DBG1(DBG_CFG, "coupling file path unspecified");
+               destroy(this);
+               return NULL;
+       }
+       this->f = fopen(path, "a+");
+       if (!this->f)
+       {
+               DBG1(DBG_CFG, "opening coupling file '%s' failed: %s",
+                        path, strerror(errno));
+               destroy(this);
+               return NULL;
+       }
+       setlinebuf(this->f);
+       return &this->public;
+}
diff --git a/src/libcharon/plugins/coupling/coupling_validator.h b/src/libcharon/plugins/coupling/coupling_validator.h
new file mode 100644 (file)
index 0000000..d6b4d37
--- /dev/null
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2011 Martin Willi
+ * Copyright (C) 2011 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 coupling_validator coupling_validator
+ * @{ @ingroup coupling
+ */
+
+#ifndef COUPLING_VALIDATOR_H_
+#define COUPLING_VALIDATOR_H_
+
+#include <credentials/cert_validator.h>
+
+typedef struct coupling_validator_t coupling_validator_t;
+
+/**
+ * Validator that couples authenticated certificates permanently.
+ */
+struct coupling_validator_t {
+
+       /**
+        * Implements cert_validator_t interface.
+        */
+       cert_validator_t validator;
+
+       /**
+        * Destroy a coupling_validator_t.
+        */
+       void (*destroy)(coupling_validator_t *this);
+};
+
+/**
+ * Create a coupling_validator instance.
+ */
+coupling_validator_t *coupling_validator_create();
+
+#endif /** COUPLING_VALIDATOR_H_ @}*/