Implemented crypter on top of AF_ALG

src/libstrongswan/plugins/af_alg/Makefile.am

@@ -12,6 +12,7 @@ endif
 libstrongswan_af_alg_la_SOURCES = \
 	af_alg_plugin.h af_alg_plugin.c \
 	af_alg_hasher.h af_alg_hasher.c \
-	af_alg_signer.h af_alg_signer.c
+	af_alg_signer.h af_alg_signer.c \
+	af_alg_crypter.h af_alg_crypter.c
 
 libstrongswan_af_alg_la_LDFLAGS = -module -avoid-version

src/libstrongswan/plugins/af_alg/af_alg_crypter.c

@@ -0,0 +1,295 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 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 "af_alg_crypter.h"
+
+#include <unistd.h>
+#include <errno.h>
+#include <linux/socket.h>
+#include <linux/if_alg.h>
+
+#include <debug.h>
+
+#ifndef AF_ALG
+#define AF_ALG		38
+#endif /* AF_ALG */
+
+#ifndef SOL_ALG
+#define SOL_ALG 279
+#endif /* SOL_ALG */
+
+typedef struct private_af_alg_crypter_t private_af_alg_crypter_t;
+
+/**
+ * Private data of af_alg_crypter_t
+ */
+struct private_af_alg_crypter_t {
+
+	/**
+	 * Public part of this class.
+	 */
+	af_alg_crypter_t public;
+
+	/**
+	 * Transform fd
+	 */
+	int tfm;
+
+	/**
+	 * Size of the truncated signature
+	 */
+	size_t block_size;
+
+	/**
+	 * Size of the keymat
+	 */
+	size_t keymat_size;
+
+	/**
+	 * Size of initialization vector
+	 */
+	size_t iv_size;
+};
+
+/**
+ * Get the kernel algorithm string and block/key size for our identifier
+ */
+static size_t lookup_alg(encryption_algorithm_t algo, char *name,
+						 size_t key_size, size_t *keymat_size, size_t *iv_size)
+{
+	static struct {
+		encryption_algorithm_t id;
+		char *name;
+		size_t block_size;
+		/* key size of the algorithm */
+		size_t key_size;
+		/* size of the keying material (key + nonce for ctr mode) */
+		size_t keymat_size;
+		size_t iv_size;
+	} algs[] = {
+		{ENCR_DES,			"cbc(des)",					 8,	 8,	 8,	 8,	},
+		{ENCR_3DES,			"cbc(des3_ede)",			 8,	24,	24,	 8,	},
+		{ENCR_AES_CBC,		"cbc(aes)",					16,	16,	16,	16,	},
+		{ENCR_AES_CBC,		"cbc(aes)",					16,	24,	24,	16,	},
+		{ENCR_AES_CBC,		"cbc(aes)",					16,	32,	32,	16,	},
+		{ENCR_AES_CTR,		"rfc3686(ctr(aes))",		 1,	16,	20,	 8,	},
+		{ENCR_AES_CTR,		"rfc3686(ctr(aes))",		 1,	24,	28,	 8,	},
+		{ENCR_AES_CTR,		"rfc3686(ctr(aes))",		 1,	32,	36,	 8,	},
+		{ENCR_CAMELLIA_CBC,	"cbc(camellia)",			16,	16,	16,	16,	},
+		{ENCR_CAMELLIA_CBC,	"cbc(camellia)",			16,	24,	24,	16,	},
+		{ENCR_CAMELLIA_CBC,	"cbc(camellia)",			16,	32,	32,	16,	},
+		{ENCR_CAMELLIA_CTR,	"rfc3686(ctr(camellia))",	 1,	16,	20,	 8,	},
+		{ENCR_CAMELLIA_CTR,	"rfc3686(ctr(camellia))",	 1,	24,	28,	 8,	},
+		{ENCR_CAMELLIA_CTR,	"rfc3686(ctr(camellia))",	 1,	32,	36,	 8,	},
+	};
+	int i;
+
+	for (i = 0; i < countof(algs); i++)
+	{
+		if (algs[i].id == algo &&
+			(key_size == 0 || algs[i].key_size == key_size))
+		{
+			strcpy(name, algs[i].name);
+			*keymat_size = algs[i].keymat_size;
+			*iv_size = algs[i].iv_size;
+			return algs[i].block_size;
+		}
+	}
+	return 0;
+}
+
+/**
+ * Do the en-/decryption operation
+ */
+static void crypt(private_af_alg_crypter_t *this, u_int32_t type, chunk_t iv,
+				  chunk_t in, char *out)
+{
+	struct msghdr msg = {};
+	struct cmsghdr *cmsg;
+	struct af_alg_iv *ivm;
+	struct iovec iov;
+	char buf[CMSG_SPACE(sizeof(type)) +
+			 CMSG_SPACE(offsetof(struct af_alg_iv, iv) + iv.len)];
+	ssize_t len;
+	int op;
+
+	while ((op = accept(this->tfm, NULL, 0)) == -1)
+	{
+		DBG1(DBG_LIB, "accepting AF_ALG crypter failed: %s", strerror(errno));
+		sleep(1);
+	}
+
+	memset(buf, 0, sizeof(buf));
+
+	msg.msg_control = buf;
+	msg.msg_controllen = sizeof(buf);
+
+	cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_level = SOL_ALG;
+	cmsg->cmsg_type = ALG_SET_OP;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(type));
+	*(u_int32_t*)CMSG_DATA(cmsg) = type;
+
+	cmsg = CMSG_NXTHDR(&msg, cmsg);
+	cmsg->cmsg_level = SOL_ALG;
+	cmsg->cmsg_type = ALG_SET_IV;
+	cmsg->cmsg_len = CMSG_LEN(offsetof(struct af_alg_iv, iv) + iv.len);
+	ivm = (void*)CMSG_DATA(cmsg);
+	ivm->ivlen = iv.len;
+	memcpy(ivm->iv, iv.ptr, iv.len);
+
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	while (in.len)
+	{
+		iov.iov_base = in.ptr;
+		iov.iov_len = in.len;
+
+		len = sendmsg(op, &msg, 0);
+		if (len == -1)
+		{
+			DBG1(DBG_LIB, "writing to AF_ALG crypter failed: %s",
+				 strerror(errno));
+			sleep(1);
+			continue;
+		}
+		if (read(op, out, len) != len)
+		{
+			DBG1(DBG_LIB, "reading from AF_ALG crypter failed: %s",
+				 strerror(errno));
+		}
+		in = chunk_skip(in, len);
+		/* no IV for subsequent data chunks */
+		msg.msg_controllen = 0;
+	}
+	close(op);
+}
+
+METHOD(crypter_t, decrypt, void,
+	private_af_alg_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *dst)
+{
+	if (dst)
+	{
+		*dst = chunk_alloc(data.len);
+		crypt(this, ALG_OP_DECRYPT, iv, data, dst->ptr);
+	}
+	else
+	{
+		crypt(this, ALG_OP_DECRYPT, iv, data, data.ptr);
+	}
+}
+
+METHOD(crypter_t, encrypt, void,
+	private_af_alg_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *dst)
+{
+	if (dst)
+	{
+		*dst = chunk_alloc(data.len);
+		crypt(this, ALG_OP_ENCRYPT, iv, data, dst->ptr);
+	}
+	else
+	{
+		crypt(this, ALG_OP_ENCRYPT, iv, data, data.ptr);
+	}
+}
+
+METHOD(crypter_t, get_block_size, size_t,
+	private_af_alg_crypter_t *this)
+{
+	return this->block_size;
+}
+
+METHOD(crypter_t, get_iv_size, size_t,
+	private_af_alg_crypter_t *this)
+{
+	return this->iv_size;
+}
+
+METHOD(crypter_t, get_key_size, size_t,
+	private_af_alg_crypter_t *this)
+{
+	return this->keymat_size;
+}
+
+METHOD(crypter_t, set_key, void,
+	private_af_alg_crypter_t *this, chunk_t key)
+{
+	if (setsockopt(this->tfm, SOL_ALG, ALG_SET_KEY, key.ptr, key.len) == -1)
+	{
+		DBG1(DBG_LIB, "setting AF_ALG key %B failed: %s", &key, strerror(errno));
+	}
+}
+
+METHOD(crypter_t, destroy, void,
+	private_af_alg_crypter_t *this)
+{
+	close(this->tfm);
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+af_alg_crypter_t *af_alg_crypter_create(encryption_algorithm_t algo,
+										size_t key_size)
+{
+	private_af_alg_crypter_t *this;
+	struct sockaddr_alg sa = {
+		.salg_family = AF_ALG,
+		.salg_type = "skcipher",
+	};
+	size_t block_size, keymat_size, iv_size;
+
+	block_size = lookup_alg(algo, sa.salg_name, key_size,
+							&keymat_size, &iv_size);
+	if (!block_size)
+	{	/* not supported by kernel */
+		return NULL;
+	}
+
+	INIT(this,
+		.public = {
+			.crypter = {
+				.encrypt = _encrypt,
+				.decrypt = _decrypt,
+				.get_block_size = _get_block_size,
+				.get_iv_size = _get_iv_size,
+				.get_key_size = _get_key_size,
+				.set_key = _set_key,
+				.destroy = _destroy,
+			},
+		},
+		.block_size = block_size,
+		.keymat_size = keymat_size,
+		.iv_size = iv_size,
+		.tfm = socket(AF_ALG, SOCK_SEQPACKET, 0),
+	);
+
+	if (this->tfm == -1)
+	{
+		DBG1(DBG_LIB, "opening AF_ALG socket failed: %s", strerror(errno));
+		free(this);
+		return NULL;
+	}
+	if (bind(this->tfm, (struct sockaddr*)&sa, sizeof(sa)) == -1)
+	{
+		DBG1(DBG_LIB, "binding AF_ALG socket for '%s' failed: %s",
+			 sa.salg_name, strerror(errno));
+		destroy(this);
+		return NULL;
+	}
+	return &this->public;
+}

src/libstrongswan/plugins/af_alg/af_alg_crypter.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 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 af_alg_crypter af_alg_crypter
+ * @{ @ingroup af_alg
+ */
+
+#ifndef AF_ALG_CRYPTER_H_
+#define AF_ALG_CRYPTER_H_
+
+typedef struct af_alg_crypter_t af_alg_crypter_t;
+
+#include <crypto/crypters/crypter.h>
+
+/**
+ * Implementation of signers using AF_ALG.
+ */
+struct af_alg_crypter_t {
+
+	/**
+	 * The crypter_t interface.
+	 */
+	crypter_t crypter;
+};
+
+/**
+ * Constructor to create af_alg_crypter_t.
+ *
+ * @param algo			algorithm to implement
+ * @param key_size		key size in bytes
+ * @return				af_alg_crypter_t, NULL if not supported
+ */
+af_alg_crypter_t *af_alg_crypter_create(encryption_algorithm_t algo,
+										size_t key_size);
+
+#endif /** AF_ALG_CRYPTER_H_ @}*/

src/libstrongswan/plugins/af_alg/af_alg_plugin.c

@@ -19,6 +19,7 @@
 
 #include "af_alg_hasher.h"
 #include "af_alg_signer.h"
+#include "af_alg_crypter.h"
 
 typedef struct private_af_alg_plugin_t private_af_alg_plugin_t;
 
@@ -40,6 +41,8 @@ METHOD(plugin_t, destroy, void,
 					(hasher_constructor_t)af_alg_hasher_create);
 	lib->crypto->remove_signer(lib->crypto,
 					(signer_constructor_t)af_alg_signer_create);
+	lib->crypto->remove_crypter(lib->crypto,
+					(crypter_constructor_t)af_alg_crypter_create);
 
 	free(this);
 }
@@ -101,5 +104,18 @@ plugin_t *af_alg_plugin_create()
 	lib->crypto->add_signer(lib->crypto, AUTH_CAMELLIA_XCBC_96,
 					(signer_constructor_t)af_alg_signer_create);
 
+	lib->crypto->add_crypter(lib->crypto, ENCR_DES,
+					(crypter_constructor_t)af_alg_crypter_create);
+	lib->crypto->add_crypter(lib->crypto, ENCR_3DES,
+					(crypter_constructor_t)af_alg_crypter_create);
+	lib->crypto->add_crypter(lib->crypto, ENCR_AES_CBC,
+					(crypter_constructor_t)af_alg_crypter_create);
+	lib->crypto->add_crypter(lib->crypto, ENCR_AES_CTR,
+					(crypter_constructor_t)af_alg_crypter_create);
+	lib->crypto->add_crypter(lib->crypto, ENCR_CAMELLIA_CBC,
+					(crypter_constructor_t)af_alg_crypter_create);
+	lib->crypto->add_crypter(lib->crypto, ENCR_CAMELLIA_CTR,
+					(crypter_constructor_t)af_alg_crypter_create);
+
 	return &this->public.plugin;
 }