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-rw-r--r--src/openvpn/crypto_polarssl.c605
1 files changed, 605 insertions, 0 deletions
diff --git a/src/openvpn/crypto_polarssl.c b/src/openvpn/crypto_polarssl.c
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+++ b/src/openvpn/crypto_polarssl.c
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+/*
+ * OpenVPN -- An application to securely tunnel IP networks
+ * over a single TCP/UDP port, with support for SSL/TLS-based
+ * session authentication and key exchange,
+ * packet encryption, packet authentication, and
+ * packet compression.
+ *
+ * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ * Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (see the file COPYING included with this
+ * distribution); if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/**
+ * @file Data Channel Cryptography PolarSSL-specific backend interface
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#if defined(ENABLE_CRYPTO) && defined(ENABLE_CRYPTO_POLARSSL)
+
+#include "errlevel.h"
+#include "basic.h"
+#include "buffer.h"
+#include "integer.h"
+#include "crypto_backend.h"
+#include "otime.h"
+#include "misc.h"
+
+#include <polarssl/des.h>
+#include <polarssl/md5.h>
+#include <polarssl/cipher.h>
+#include <polarssl/havege.h>
+
+#include <polarssl/entropy.h>
+
+/*
+ *
+ * Hardware engine support. Allows loading/unloading of engines.
+ *
+ */
+
+void
+crypto_init_lib_engine (const char *engine_name)
+{
+ msg (M_WARN, "Note: PolarSSL hardware crypto engine functionality is not "
+ "available");
+}
+
+/*
+ *
+ * Functions related to the core crypto library
+ *
+ */
+
+void
+crypto_init_lib (void)
+{
+}
+
+void
+crypto_uninit_lib (void)
+{
+}
+
+void
+crypto_clear_error (void)
+{
+}
+
+#ifdef DMALLOC
+void
+crypto_init_dmalloc (void)
+{
+ msg (M_ERR, "Error: dmalloc support is not available for PolarSSL.");
+}
+#endif /* DMALLOC */
+
+void
+show_available_ciphers ()
+{
+ const int *ciphers = cipher_list();
+
+#ifndef ENABLE_SMALL
+ printf ("The following ciphers and cipher modes are available\n"
+ "for use with " PACKAGE_NAME ". Each cipher shown below may be\n"
+ "used as a parameter to the --cipher option. The default\n"
+ "key size is shown as well as whether or not it can be\n"
+ "changed with the --keysize directive. Using a CBC mode\n"
+ "is recommended.\n\n");
+#endif
+
+ while (*ciphers != 0)
+ {
+ const cipher_info_t *info = cipher_info_from_type(*ciphers);
+
+ if (info && info->mode == POLARSSL_MODE_CBC)
+ printf ("%s %d bit default key\n",
+ info->name, info->key_length);
+
+ ciphers++;
+ }
+ printf ("\n");
+}
+
+void
+show_available_digests ()
+{
+ const int *digests = md_list();
+
+#ifndef ENABLE_SMALL
+ printf ("The following message digests are available for use with\n"
+ PACKAGE_NAME ". A message digest is used in conjunction with\n"
+ "the HMAC function, to authenticate received packets.\n"
+ "You can specify a message digest as parameter to\n"
+ "the --auth option.\n\n");
+#endif
+
+ while (*digests != 0)
+ {
+ const md_info_t *info = md_info_from_type(*digests);
+
+ if (info)
+ printf ("%s %d bit default key\n",
+ info->name, info->size * 8);
+ digests++;
+ }
+ printf ("\n");
+}
+
+void
+show_available_engines ()
+{
+ printf ("Sorry, PolarSSL hardware crypto engine functionality is not "
+ "available\n");
+}
+
+/*
+ *
+ * Random number functions, used in cases where we want
+ * reasonably strong cryptographic random number generation
+ * without depleting our entropy pool. Used for random
+ * IV values and a number of other miscellaneous tasks.
+ *
+ */
+
+/*
+ * Initialise the given ctr_drbg context, using a personalisation string and an
+ * entropy gathering function.
+ */
+ctr_drbg_context * rand_ctx_get()
+{
+ static entropy_context ec = {0};
+ static ctr_drbg_context cd_ctx = {0};
+ static bool rand_initialised = false;
+
+ if (!rand_initialised)
+ {
+ struct gc_arena gc = gc_new();
+ struct buffer pers_string = alloc_buf_gc(100, &gc);
+
+ /*
+ * Personalisation string, should be as unique as possible (see NIST
+ * 800-90 section 8.7.1). We have very little information at this stage.
+ * Include Program Name, memory address of the context and PID.
+ */
+ buf_printf(&pers_string, "OpenVPN %0u %p %s", platform_getpid(), &cd_ctx, time_string(0, 0, 0, &gc));
+
+ /* Initialise PolarSSL RNG, and built-in entropy sources */
+ entropy_init(&ec);
+
+ if (0 != ctr_drbg_init(&cd_ctx, entropy_func, &ec, BPTR(&pers_string), BLEN(&pers_string)))
+ msg (M_FATAL, "Failed to initialize random generator");
+
+ gc_free(&gc);
+ rand_initialised = true;
+ }
+
+ return &cd_ctx;
+}
+
+#ifdef ENABLE_PREDICTION_RESISTANCE
+void rand_ctx_enable_prediction_resistance()
+{
+ ctr_drbg_context *cd_ctx = rand_ctx_get();
+
+ ctr_drbg_set_prediction_resistance(cd_ctx, 1);
+}
+#endif /* ENABLE_PREDICTION_RESISTANCE */
+
+int
+rand_bytes (uint8_t *output, int len)
+{
+ ctr_drbg_context *rng_ctx = rand_ctx_get();
+
+ while (len > 0)
+ {
+ const size_t blen = min_int (len, CTR_DRBG_MAX_REQUEST);
+ if (0 != ctr_drbg_random(rng_ctx, output, blen))
+ return 0;
+
+ output += blen;
+ len -= blen;
+ }
+
+ return 1;
+}
+
+/*
+ *
+ * Key functions, allow manipulation of keys.
+ *
+ */
+
+
+int
+key_des_num_cblocks (const cipher_info_t *kt)
+{
+ int ret = 0;
+ if (kt->type == POLARSSL_CIPHER_DES_CBC)
+ ret = 1;
+ if (kt->type == POLARSSL_CIPHER_DES_EDE_CBC)
+ ret = 2;
+ if (kt->type == POLARSSL_CIPHER_DES_EDE3_CBC)
+ ret = 3;
+
+ dmsg (D_CRYPTO_DEBUG, "CRYPTO INFO: n_DES_cblocks=%d", ret);
+ return ret;
+}
+
+bool
+key_des_check (uint8_t *key, int key_len, int ndc)
+{
+ int i;
+ struct buffer b;
+
+ buf_set_read (&b, key, key_len);
+
+ for (i = 0; i < ndc; ++i)
+ {
+ unsigned char *key = buf_read_alloc(&b, DES_KEY_SIZE);
+ if (!key)
+ {
+ msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: insufficient key material");
+ goto err;
+ }
+ if (0 != des_key_check_weak(key))
+ {
+ msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: weak key detected");
+ goto err;
+ }
+ if (0 != des_key_check_key_parity(key))
+ {
+ msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: bad parity detected");
+ goto err;
+ }
+ }
+ return true;
+
+ err:
+ return false;
+}
+
+void
+key_des_fixup (uint8_t *key, int key_len, int ndc)
+{
+ int i;
+ struct buffer b;
+
+ buf_set_read (&b, key, key_len);
+ for (i = 0; i < ndc; ++i)
+ {
+ unsigned char *key = buf_read_alloc(&b, DES_KEY_SIZE);
+ if (!key)
+ {
+ msg (D_CRYPT_ERRORS, "CRYPTO INFO: fixup_key_DES: insufficient key material");
+ return;
+ }
+ des_key_set_parity(key);
+ }
+}
+
+/*
+ *
+ * Generic cipher key type functions
+ *
+ */
+
+
+const cipher_info_t *
+cipher_kt_get (const char *ciphername)
+{
+ const cipher_info_t *cipher = NULL;
+
+ ASSERT (ciphername);
+
+ cipher = cipher_info_from_string(ciphername);
+
+ if (NULL == cipher)
+ msg (M_FATAL, "Cipher algorithm '%s' not found", ciphername);
+
+ if (cipher->key_length/8 > MAX_CIPHER_KEY_LENGTH)
+ msg (M_FATAL, "Cipher algorithm '%s' uses a default key size (%d bytes) which is larger than " PACKAGE_NAME "'s current maximum key size (%d bytes)",
+ ciphername,
+ cipher->key_length/8,
+ MAX_CIPHER_KEY_LENGTH);
+
+ return cipher;
+}
+
+const char *
+cipher_kt_name (const cipher_info_t *cipher_kt)
+{
+ if (NULL == cipher_kt)
+ return "[null-cipher]";
+ return cipher_kt->name;
+}
+
+int
+cipher_kt_key_size (const cipher_info_t *cipher_kt)
+{
+ if (NULL == cipher_kt)
+ return 0;
+ return cipher_kt->key_length/8;
+}
+
+int
+cipher_kt_iv_size (const cipher_info_t *cipher_kt)
+{
+ if (NULL == cipher_kt)
+ return 0;
+ return cipher_kt->iv_size;
+}
+
+int
+cipher_kt_block_size (const cipher_info_t *cipher_kt)
+{
+ if (NULL == cipher_kt)
+ return 0;
+ return cipher_kt->block_size;
+}
+
+int
+cipher_kt_mode (const cipher_info_t *cipher_kt)
+{
+ ASSERT(NULL != cipher_kt);
+ return cipher_kt->mode;
+}
+
+
+/*
+ *
+ * Generic cipher context functions
+ *
+ */
+
+
+void
+cipher_ctx_init (cipher_context_t *ctx, uint8_t *key, int key_len,
+ const cipher_info_t *kt, int enc)
+{
+ ASSERT(NULL != kt && NULL != ctx);
+
+ CLEAR (*ctx);
+
+ if (0 != cipher_init_ctx(ctx, kt))
+ msg (M_FATAL, "PolarSSL cipher context init #1");
+
+ if (0 != cipher_setkey(ctx, key, key_len*8, enc))
+ msg (M_FATAL, "PolarSSL cipher set key");
+
+ /* make sure we used a big enough key */
+ ASSERT (ctx->key_length <= key_len*8);
+}
+
+void cipher_ctx_cleanup (cipher_context_t *ctx)
+{
+ cipher_free_ctx(ctx);
+}
+
+int cipher_ctx_iv_length (const cipher_context_t *ctx)
+{
+ return cipher_get_iv_size(ctx);
+}
+
+int cipher_ctx_block_size(const cipher_context_t *ctx)
+{
+ return cipher_get_block_size(ctx);
+}
+
+int cipher_ctx_mode (const cipher_context_t *ctx)
+{
+ ASSERT(NULL != ctx);
+
+ return cipher_kt_mode(ctx->cipher_info);
+}
+
+int cipher_ctx_reset (cipher_context_t *ctx, uint8_t *iv_buf)
+{
+ return 0 == cipher_reset(ctx, iv_buf);
+}
+
+int cipher_ctx_update (cipher_context_t *ctx, uint8_t *dst, int *dst_len,
+ uint8_t *src, int src_len)
+{
+ int retval = 0;
+ size_t s_dst_len = *dst_len;
+
+ retval = cipher_update(ctx, src, (size_t)src_len, dst, &s_dst_len);
+
+ *dst_len = s_dst_len;
+
+ return 0 == retval;
+}
+
+int cipher_ctx_final (cipher_context_t *ctx, uint8_t *dst, int *dst_len)
+{
+ int retval = 0;
+ size_t s_dst_len = *dst_len;
+
+ retval = cipher_finish(ctx, dst, &s_dst_len);
+ *dst_len = s_dst_len;
+
+ return 0 == retval;
+}
+
+void
+cipher_des_encrypt_ecb (const unsigned char key[DES_KEY_LENGTH],
+ unsigned char *src,
+ unsigned char *dst)
+{
+ des_context ctx;
+
+ des_setkey_enc(&ctx, key);
+ des_crypt_ecb(&ctx, src, dst);
+}
+
+
+
+/*
+ *
+ * Generic message digest information functions
+ *
+ */
+
+
+const md_info_t *
+md_kt_get (const char *digest)
+{
+ const md_info_t *md = NULL;
+ ASSERT (digest);
+
+ md = md_info_from_string(digest);
+ if (!md)
+ msg (M_FATAL, "Message hash algorithm '%s' not found", digest);
+ if (md->size > MAX_HMAC_KEY_LENGTH)
+ msg (M_FATAL, "Message hash algorithm '%s' uses a default hash size (%d bytes) which is larger than " PACKAGE_NAME "'s current maximum hash size (%d bytes)",
+ digest,
+ md->size,
+ MAX_HMAC_KEY_LENGTH);
+ return md;
+}
+
+const char *
+md_kt_name (const md_info_t *kt)
+{
+ if (NULL == kt)
+ return "[null-digest]";
+ return md_get_name (kt);
+}
+
+int
+md_kt_size (const md_info_t *kt)
+{
+ if (NULL == kt)
+ return 0;
+ return md_get_size(kt);
+}
+
+/*
+ *
+ * Generic message digest functions
+ *
+ */
+
+int
+md_full (const md_kt_t *kt, const uint8_t *src, int src_len, uint8_t *dst)
+{
+ return 0 == md(kt, src, src_len, dst);
+}
+
+
+void
+md_ctx_init (md_context_t *ctx, const md_info_t *kt)
+{
+ ASSERT(NULL != ctx && NULL != kt);
+
+ CLEAR(*ctx);
+
+ ASSERT(0 == md_init_ctx(ctx, kt));
+ ASSERT(0 == md_starts(ctx));
+}
+
+void
+md_ctx_cleanup(md_context_t *ctx)
+{
+}
+
+int
+md_ctx_size (const md_context_t *ctx)
+{
+ if (NULL == ctx)
+ return 0;
+ return md_get_size(ctx->md_info);
+}
+
+void
+md_ctx_update (md_context_t *ctx, const uint8_t *src, int src_len)
+{
+ ASSERT(0 == md_update(ctx, src, src_len));
+}
+
+void
+md_ctx_final (md_context_t *ctx, uint8_t *dst)
+{
+ ASSERT(0 == md_finish(ctx, dst));
+ ASSERT(0 == md_free_ctx(ctx));
+}
+
+
+/*
+ *
+ * Generic HMAC functions
+ *
+ */
+
+
+/*
+ * TODO: re-enable dmsg for crypto debug
+ */
+void
+hmac_ctx_init (md_context_t *ctx, const uint8_t *key, int key_len, const md_info_t *kt)
+{
+ ASSERT(NULL != kt && NULL != ctx);
+
+ CLEAR(*ctx);
+
+ ASSERT(0 == md_init_ctx(ctx, kt));
+ ASSERT(0 == md_hmac_starts(ctx, key, key_len));
+
+ /* make sure we used a big enough key */
+ ASSERT (md_get_size(kt) <= key_len);
+}
+
+void
+hmac_ctx_cleanup(md_context_t *ctx)
+{
+ ASSERT(0 == md_free_ctx(ctx));
+}
+
+int
+hmac_ctx_size (const md_context_t *ctx)
+{
+ if (NULL == ctx)
+ return 0;
+ return md_get_size(ctx->md_info);
+}
+
+void
+hmac_ctx_reset (md_context_t *ctx)
+{
+ ASSERT(0 == md_hmac_reset(ctx));
+}
+
+void
+hmac_ctx_update (md_context_t *ctx, const uint8_t *src, int src_len)
+{
+ ASSERT(0 == md_hmac_update(ctx, src, src_len));
+}
+
+void
+hmac_ctx_final (md_context_t *ctx, uint8_t *dst)
+{
+ ASSERT(0 == md_hmac_finish(ctx, dst));
+}
+
+#endif /* ENABLE_CRYPTO && ENABLE_CRYPTO_POLARSSL */
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