diff --git a/configure.in b/configure.in index c3dd7280f..ea86c59e5 100644 --- a/configure.in +++ b/configure.in @@ -571,6 +571,16 @@ AC_ARG_ENABLE( fi], ) +AC_ARG_ENABLE( + [agent], + AS_HELP_STRING([--enable-agent],[enables the ssh-agent signing plugin. (default is NO).]), + [if test x$enableval = xyes; then + agent=true + else + agent=false + fi], +) + AC_ARG_ENABLE( [uci], AS_HELP_STRING([--enable-uci],[enable OpenWRT UCI configuration plugin (default is NO).]), @@ -793,6 +803,9 @@ fi if test x$openssl = xtrue; then libstrongswan_plugins=${libstrongswan_plugins}" openssl" fi +if test x$agent = xtrue; then + libstrongswan_plugins=${libstrongswan_plugins}" agent" +fi if test x$gmp = xtrue; then libstrongswan_plugins=${libstrongswan_plugins}" gmp" fi @@ -823,6 +836,7 @@ AM_CONDITIONAL(USE_MYSQL, test x$mysql = xtrue) AM_CONDITIONAL(USE_SQLITE, test x$sqlite = xtrue) AM_CONDITIONAL(USE_PADLOCK, test x$padlock = xtrue) AM_CONDITIONAL(USE_OPENSSL, test x$openssl = xtrue) +AM_CONDITIONAL(USE_AGENT, test x$agent = xtrue) dnl charon plugins dnl ============== @@ -900,6 +914,7 @@ AC_OUTPUT( src/libstrongswan/plugins/sqlite/Makefile src/libstrongswan/plugins/padlock/Makefile src/libstrongswan/plugins/openssl/Makefile + src/libstrongswan/plugins/agent/Makefile src/libstrongswan/fips/Makefile src/libcrypto/Makefile src/libfreeswan/Makefile diff --git a/src/libstrongswan/Makefile.am b/src/libstrongswan/Makefile.am index 8976a79a0..08409d503 100644 --- a/src/libstrongswan/Makefile.am +++ b/src/libstrongswan/Makefile.am @@ -156,6 +156,10 @@ if USE_OPENSSL SUBDIRS += plugins/openssl endif +if USE_AGENT + SUBDIRS += plugins/agent +endif + if USE_INTEGRITY_TEST SUBDIRS += fips endif diff --git a/src/libstrongswan/plugins/agent/Makefile.am b/src/libstrongswan/plugins/agent/Makefile.am new file mode 100644 index 000000000..bc022aa26 --- /dev/null +++ b/src/libstrongswan/plugins/agent/Makefile.am @@ -0,0 +1,12 @@ + +INCLUDES = -I$(top_srcdir)/src/libstrongswan + +AM_CFLAGS = -rdynamic + +plugin_LTLIBRARIES = libstrongswan-agent.la + +libstrongswan_agent_la_SOURCES = agent_plugin.h agent_plugin.c \ + agent_private_key.c agent_private_key.h + +libstrongswan_agent_la_LDFLAGS = -module + diff --git a/src/libstrongswan/plugins/agent/agent_plugin.c b/src/libstrongswan/plugins/agent/agent_plugin.c new file mode 100644 index 000000000..474171ad1 --- /dev/null +++ b/src/libstrongswan/plugins/agent/agent_plugin.c @@ -0,0 +1,59 @@ +/* + * Copyright (C) 2008 Martin Willi + * Hochschule fuer Technik Rapperswil + * + * 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 . + * + * 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. + * + * $Id$ + */ + +#include "agent_plugin.h" + +#include +#include "agent_private_key.h" + +typedef struct private_agent_plugin_t private_agent_plugin_t; + +/** + * private data of agent_plugin + */ +struct private_agent_plugin_t { + + /** + * public functions + */ + agent_plugin_t public; +}; + +/** + * Implementation of agent_plugin_t.agenttroy + */ +static void destroy(private_agent_plugin_t *this) +{ + lib->creds->remove_builder(lib->creds, + (builder_constructor_t)agent_private_key_builder); + free(this); +} + +/* + * see header file + */ +plugin_t *plugin_create() +{ + private_agent_plugin_t *this = malloc_thing(private_agent_plugin_t); + + this->public.plugin.destroy = (void(*)(plugin_t*))destroy; + + lib->creds->add_builder(lib->creds, CRED_PRIVATE_KEY, KEY_RSA, + (builder_constructor_t)agent_private_key_builder); + return &this->public.plugin; +} + diff --git a/src/libstrongswan/plugins/agent/agent_plugin.h b/src/libstrongswan/plugins/agent/agent_plugin.h new file mode 100644 index 000000000..d12dd44ac --- /dev/null +++ b/src/libstrongswan/plugins/agent/agent_plugin.h @@ -0,0 +1,47 @@ +/* + * Copyright (C) 2008 Martin Willi + * Hochschule fuer Technik Rapperswil + * + * 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 . + * + * 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 agent_p agent + * @ingroup plugins + * + * @defgroup agent_plugin agent_plugin + * @{ @ingroup agent_p + */ + +#ifndef AGENT_PLUGIN_H_ +#define AGENT_PLUGIN_H_ + +#include + +typedef struct agent_plugin_t agent_plugin_t; + +/** + * Plugin to use private keys loaded in a ssh-agent. + */ +struct agent_plugin_t { + + /** + * implements plugin interface + */ + plugin_t plugin; +}; + +/** + * Create a agent_plugin instance. + */ +plugin_t *plugin_create(); + +#endif /* AGENT_PLUGIN_H_ @}*/ diff --git a/src/libstrongswan/plugins/agent/agent_private_key.c b/src/libstrongswan/plugins/agent/agent_private_key.c new file mode 100644 index 000000000..83f22b6f7 --- /dev/null +++ b/src/libstrongswan/plugins/agent/agent_private_key.c @@ -0,0 +1,540 @@ +/* + * Copyright (C) 2008 Martin Willi + * Hochschule fuer Technik Rapperswil + * + * 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 . + * + * 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. + * + * $Id$ + */ + +#include "agent_private_key.h" + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#ifndef UNIX_PATH_MAX +#define UNIX_PATH_MAX 108 +#endif /* UNIX_PATH_MAX */ + +typedef struct private_agent_private_key_t private_agent_private_key_t; +typedef enum agent_msg_type_t agent_msg_type_t; + +/** + * Private data of a agent_private_key_t object. + */ +struct private_agent_private_key_t { + /** + * Public interface for this signer. + */ + agent_private_key_t public; + + /** + * ssh-agent unix socket connection + */ + int socket; + + /** + * key identity blob in ssh format + */ + chunk_t key; + + /** + * keysize in bytes + */ + size_t key_size; + + /** + * Keyid formed as a SHA-1 hash of a publicKey object + */ + identification_t* keyid; + + /** + * Keyid formed as a SHA-1 hash of a publicKeyInfo object + */ + identification_t* keyid_info; + + /** + * reference count + */ + refcount_t ref; +}; + +/** + * Message types for ssh-agent protocol + */ +enum agent_msg_type_t { + SSH_AGENT_FAILURE = 5, + SSH_AGENT_SUCCESS = 6, + SSH_AGENT_ID_REQUEST = 11, + SSH_AGENT_ID_RESPONSE = 12, + SSH_AGENT_SIGN_REQUEST = 13, + SSH_AGENT_SIGN_RESPONSE = 14, +}; + +/** + * read a byte from a blob + */ +static u_char read_byte(chunk_t *blob) +{ + u_char val; + + if (blob->len < sizeof(u_char)) + { + return 0; + } + val = *(blob->ptr); + *blob = chunk_skip(*blob, sizeof(u_char)); + return val; +} + +/** + * read a u_int32_t from a blob + */ +static u_int32_t read_uint32(chunk_t *blob) +{ + u_int32_t val; + + if (blob->len < sizeof(u_int32_t)) + { + return 0; + } + val = ntohl(*(u_int32_t*)blob->ptr); + *blob = chunk_skip(*blob, sizeof(u_int32_t)); + return val; +} + +/** + * read a ssh-agent "string" length/value from a blob + */ +static chunk_t read_string(chunk_t *blob) +{ + int len; + chunk_t str; + + len = read_uint32(blob); + if (len > blob->len) + { + return chunk_empty; + } + str = chunk_create(blob->ptr, len); + *blob = chunk_skip(*blob, + len); + return str; +} + +/** + * open socket connection to the ssh-agent + */ +static int open_connection(char *path) +{ + struct sockaddr_un addr; + int s; + + s = socket(AF_UNIX, SOCK_STREAM, 0); + if (s == -1) + { + DBG1("opening ssh-agent socket %s failed: %s:", path, strerror(errno)); + return -1; + } + + addr.sun_family = AF_UNIX; + addr.sun_path[UNIX_PATH_MAX - 1] = '\0'; + strncpy(addr.sun_path, path, UNIX_PATH_MAX - 1); + + if (connect(s, (struct sockaddr*)&addr, SUN_LEN(&addr)) != 0) + { + DBG1("connecting to ssh-agent socket failed: %s", strerror(errno)); + close(s); + return -1; + } + return s; +} + +/** + * Get the first usable key from the agent + */ +static bool read_key(private_agent_private_key_t *this) +{ + int len, count; + char buf[2048]; + chunk_t blob = chunk_from_buf(buf), key, type, tmp; + + len = htonl(1); + write(this->socket, &len, sizeof(len)); + buf[0] = SSH_AGENT_ID_REQUEST; + write(this->socket, &buf, 1); + + blob.len = read(this->socket, blob.ptr, blob.len); + + if (blob.len < sizeof(u_int32_t) + sizeof(u_char) || + read_uint32(&blob) != blob.len || + read_byte(&blob) != SSH_AGENT_ID_RESPONSE) + { + DBG1("received invalid ssh-agent identity response"); + return FALSE; + } + count = read_uint32(&blob); + + while (blob.len) + { + key = read_string(&blob); + if (key.len) + { + tmp = key; + type = read_string(&tmp); + read_string(&tmp); + tmp = read_string(&tmp); + if (type.len && strneq("ssh-rsa", type.ptr, type.len) && + tmp.len >= 512/8) + { + this->key = chunk_clone(key); + this->key_size = tmp.len; + if (tmp.ptr[0] == 0) + { + this->key_size--; + } + return TRUE; + } + continue; + } + break; + } + return FALSE; +} + +/** + * Implementation of agent_private_key.destroy. + */ +static bool sign(private_agent_private_key_t *this, signature_scheme_t scheme, + chunk_t data, chunk_t *signature) +{ + u_int32_t len, flags; + char buf[2048]; + chunk_t blob = chunk_from_buf(buf); + + if (scheme != SIGN_DEFAULT && scheme != SIGN_RSA_EMSA_PKCS1_SHA1) + { + DBG1("signature scheme %N not supported by ssh-agent", + signature_scheme_names, scheme); + return FALSE; + } + + len = htonl(1 + sizeof(u_int32_t) * 3 + this->key.len + data.len); + write(this->socket, &len, sizeof(len)); + buf[0] = SSH_AGENT_SIGN_REQUEST; + write(this->socket, &buf, 1); + + len = htonl(this->key.len); + write(this->socket, &len, sizeof(len)); + write(this->socket, this->key.ptr, this->key.len); + + len = htonl(data.len); + write(this->socket, &len, sizeof(len)); + write(this->socket, data.ptr, data.len); + + flags = htonl(0); + write(this->socket, &flags, sizeof(flags)); + + blob.len = read(this->socket, blob.ptr, blob.len); + if (blob.len < sizeof(u_int32_t) + sizeof(u_char) || + read_uint32(&blob) != blob.len || + read_byte(&blob) != SSH_AGENT_SIGN_RESPONSE) + { + DBG1("received invalid ssh-agent signature response"); + return FALSE; + } + /* parse length */ + blob = read_string(&blob); + /* skip sig type */ + read_string(&blob); + /* parse length */ + blob = read_string(&blob); + if (!blob.len) + { + DBG1("received invalid ssh-agent signature response"); + return FALSE; + } + *signature = chunk_clone(blob); + return TRUE; +} + +/** + * Implementation of agent_private_key.destroy. + */ +static key_type_t get_type(private_agent_private_key_t *this) +{ + return KEY_RSA; +} + +/** + * Implementation of agent_private_key.destroy. + */ +static bool decrypt(private_agent_private_key_t *this, + chunk_t crypto, chunk_t *plain) +{ + DBG1("private key decryption not supported by ssh-agent"); + return FALSE; +} + +/** + * Implementation of agent_private_key.destroy. + */ +static size_t get_keysize(private_agent_private_key_t *this) +{ + return this->key_size; +} + +/** + * Implementation of agent_private_key.destroy. + */ +static identification_t* get_id(private_agent_private_key_t *this, + id_type_t type) +{ + switch (type) + { + case ID_PUBKEY_INFO_SHA1: + return this->keyid_info; + case ID_PUBKEY_SHA1: + return this->keyid; + default: + return NULL; + } +} + +/** + * Implementation of agent_private_key.get_public_key. + */ +static public_key_t* get_public_key(private_agent_private_key_t *this) +{ + chunk_t key, n, e, encoded; + public_key_t *public; + + key = this->key; + read_string(&key); + e = read_string(&key); + n = read_string(&key); + encoded = asn1_wrap(ASN1_SEQUENCE, "mm", + asn1_wrap(ASN1_INTEGER, "c", n), + asn1_wrap(ASN1_INTEGER, "c", e)); + + public = lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA, + BUILD_BLOB_ASN1_DER, encoded, BUILD_END); + free(encoded.ptr); + return public; +} + +/** + * Implementation of agent_private_key.belongs_to. + */ +static bool belongs_to(private_agent_private_key_t *this, public_key_t *public) +{ + identification_t *keyid; + + if (public->get_type(public) != KEY_RSA) + { + return FALSE; + } + keyid = public->get_id(public, ID_PUBKEY_SHA1); + if (keyid && keyid->equals(keyid, this->keyid)) + { + return TRUE; + } + keyid = public->get_id(public, ID_PUBKEY_INFO_SHA1); + if (keyid && keyid->equals(keyid, this->keyid_info)) + { + return TRUE; + } + return FALSE; +} + +/** + * Build the RSA key identifier from n and e using SHA1 hashed publicKey(Info). + */ +static bool build_ids(private_agent_private_key_t *this) +{ + chunk_t publicKeyInfo, publicKey, hash, key, n, e; + hasher_t *hasher; + + key = this->key; + e = read_string(&key); + n = read_string(&key); + + hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1); + if (hasher == NULL) + { + DBG1("SHA1 hash algorithm not supported, unable to use RSA"); + return FALSE; + } + publicKey = asn1_wrap(ASN1_SEQUENCE, "cc", n, e); + hasher->allocate_hash(hasher, publicKey, &hash); + this->keyid = identification_create_from_encoding(ID_PUBKEY_SHA1, hash); + chunk_free(&hash); + + publicKeyInfo = asn1_wrap(ASN1_SEQUENCE, "cm", + asn1_algorithmIdentifier(OID_RSA_ENCRYPTION), + asn1_bitstring("m", publicKey)); + hasher->allocate_hash(hasher, publicKeyInfo, &hash); + this->keyid_info = identification_create_from_encoding(ID_PUBKEY_INFO_SHA1, hash); + chunk_free(&hash); + + hasher->destroy(hasher); + chunk_free(&publicKeyInfo); + return TRUE; +} + +/** + * Implementation of private_key_t.get_encoding. + */ +static chunk_t get_encoding(private_agent_private_key_t *this) +{ + return chunk_empty; +} + +/** + * Implementation of agent_private_key.get_ref. + */ +static private_agent_private_key_t* get_ref(private_agent_private_key_t *this) +{ + ref_get(&this->ref); + return this; +} + +/** + * Implementation of agent_private_key.destroy. + */ +static void destroy(private_agent_private_key_t *this) +{ + if (ref_put(&this->ref)) + { + close(this->socket); + DESTROY_IF(this->keyid); + DESTROY_IF(this->keyid_info); + free(this->key.ptr); + free(this); + } +} + +/** + * Internal constructor + */ +static agent_private_key_t *agent_private_key_create(char *path) +{ + private_agent_private_key_t *this = malloc_thing(private_agent_private_key_t); + + this->public.interface.get_type = (key_type_t (*)(private_key_t *this))get_type; + this->public.interface.sign = (bool (*)(private_key_t *this, signature_scheme_t scheme, chunk_t data, chunk_t *signature))sign; + this->public.interface.decrypt = (bool (*)(private_key_t *this, chunk_t crypto, chunk_t *plain))decrypt; + this->public.interface.get_keysize = (size_t (*) (private_key_t *this))get_keysize; + this->public.interface.get_id = (identification_t* (*) (private_key_t *this,id_type_t))get_id; + this->public.interface.get_public_key = (public_key_t* (*)(private_key_t *this))get_public_key; + this->public.interface.belongs_to = (bool (*) (private_key_t *this, public_key_t *public))belongs_to; + this->public.interface.get_encoding = (chunk_t(*)(private_key_t*))get_encoding; + this->public.interface.get_ref = (private_key_t* (*)(private_key_t *this))get_ref; + this->public.interface.destroy = (void (*)(private_key_t *this))destroy; + + this->socket = open_connection(path); + if (this->socket < 0) + { + free(this); + return NULL; + } + this->keyid = NULL; + this->keyid_info = NULL; + this->ref = 1; + if (!read_key(this) || !build_ids(this)) + { + destroy(this); + return NULL; + } + return &this->public; +} + +typedef struct private_builder_t private_builder_t; +/** + * Builder implementation for key loading/generation + */ +struct private_builder_t { + /** implements the builder interface */ + builder_t public; + /** loaded/generated private key */ + agent_private_key_t *key; +}; + +/** + * Implementation of builder_t.build + */ +static agent_private_key_t *build(private_builder_t *this) +{ + agent_private_key_t *key = this->key; + + free(this); + return key; +} + +/** + * Implementation of builder_t.add + */ +static void add(private_builder_t *this, builder_part_t part, ...) +{ + va_list args; + + if (this->key) + { + DBG1("ignoring surplus build part %N", builder_part_names, part); + return; + } + + switch (part) + { + case BUILD_AGENT_SOCKET: + { + va_start(args, part); + this->key = agent_private_key_create(va_arg(args, char*)); + va_end(args); + break; + } + default: + DBG1("ignoring unsupported build part %N", builder_part_names, part); + break; + } +} + +/** + * Builder construction function + */ +builder_t *agent_private_key_builder(key_type_t type) +{ + private_builder_t *this; + + if (type != KEY_RSA) + { + return NULL; + } + + this = malloc_thing(private_builder_t); + + this->key = NULL; + this->public.add = (void(*)(builder_t *this, builder_part_t part, ...))add; + this->public.build = (void*(*)(builder_t *this))build; + + return &this->public; +} + diff --git a/src/libstrongswan/plugins/agent/agent_private_key.h b/src/libstrongswan/plugins/agent/agent_private_key.h new file mode 100644 index 000000000..4d678dd08 --- /dev/null +++ b/src/libstrongswan/plugins/agent/agent_private_key.h @@ -0,0 +1,48 @@ +/* + * Copyright (C) 2008 Martin Willi + * Hochschule fuer Technik Rapperswil + * + * 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 . + * + * 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 agent_private_key agent_private_key + * @{ @ingroup agent_p + */ + +#ifndef AGENT_PRIVATE_KEY_H_ +#define AGENT_PRIVATE_KEY_H_ + +#include + +typedef struct agent_private_key_t agent_private_key_t; + +/** + * private_key_t implementation using an ssh-agent. + */ +struct agent_private_key_t { + + /** + * Implements private_key_t interface + */ + private_key_t interface; +}; + +/** + * Create the builder for a private key. + * + * @param type type of the key + * @return builder instance + */ +builder_t *agent_private_key_builder(key_type_t type); + +#endif /*AGENT_PRIVATE_KEY_H_ @}*/ +