/*
* 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 Control Channel PolarSSL Backend
*/
#include "syshead.h"
#if defined(USE_SSL) && defined(USE_POLARSSL)
#include "errlevel.h"
#include "ssl_backend.h"
#include "buffer.h"
#include "misc.h"
#include "manage.h"
#include "ssl_common.h"
#include "ssl_verify_polarssl.h"
#include <polarssl/pem.h>
void
tls_init_lib()
{
}
void
tls_free_lib()
{
}
void
tls_clear_error()
{
}
static int default_ciphersuites[] =
{
SSL_EDH_RSA_AES_256_SHA,
SSL_EDH_RSA_CAMELLIA_256_SHA,
SSL_EDH_RSA_AES_128_SHA,
SSL_EDH_RSA_CAMELLIA_128_SHA,
SSL_EDH_RSA_DES_168_SHA,
SSL_RSA_AES_256_SHA,
SSL_RSA_CAMELLIA_256_SHA,
SSL_RSA_AES_128_SHA,
SSL_RSA_CAMELLIA_128_SHA,
SSL_RSA_DES_168_SHA,
SSL_RSA_RC4_128_SHA,
SSL_RSA_RC4_128_MD5,
0
};
void
tls_ctx_server_new(struct tls_root_ctx *ctx)
{
ASSERT(NULL != ctx);
CLEAR(*ctx);
ALLOC_OBJ_CLEAR(ctx->hs, havege_state);
havege_init(ctx->hs);
ALLOC_OBJ_CLEAR(ctx->dhm_ctx, dhm_context);
ALLOC_OBJ_CLEAR(ctx->priv_key, rsa_context);
ALLOC_OBJ_CLEAR(ctx->ca_chain, x509_cert);
ALLOC_OBJ_CLEAR(ctx->crt_chain, x509_cert);
ctx->endpoint = SSL_IS_SERVER;
ctx->initialised = true;
}
void
tls_ctx_client_new(struct tls_root_ctx *ctx)
{
ASSERT(NULL != ctx);
CLEAR(*ctx);
ALLOC_OBJ_CLEAR(ctx->hs, havege_state);
havege_init(ctx->hs);
ALLOC_OBJ_CLEAR(ctx->dhm_ctx, dhm_context);
ALLOC_OBJ_CLEAR(ctx->priv_key, rsa_context);
ALLOC_OBJ_CLEAR(ctx->ca_chain, x509_cert);
ALLOC_OBJ_CLEAR(ctx->crt_chain, x509_cert);
ctx->endpoint = SSL_IS_CLIENT;
ctx->initialised = true;
}
void
tls_ctx_free(struct tls_root_ctx *ctx)
{
if (ctx)
{
rsa_free(ctx->priv_key);
free(ctx->priv_key);
x509_free(ctx->ca_chain);
free(ctx->ca_chain);
x509_free(ctx->crt_chain);
free(ctx->crt_chain);
dhm_free(ctx->dhm_ctx);
free(ctx->dhm_ctx);
#if defined(ENABLE_PKCS11)
if (ctx->priv_key_pkcs11 != NULL) {
pkcs11_priv_key_free(ctx->priv_key_pkcs11);
free(ctx->priv_key_pkcs11);
}
#endif
free(ctx->hs);
if (ctx->allowed_ciphers)
free(ctx->allowed_ciphers);
CLEAR(*ctx);
ctx->initialised = false;
}
}
bool
tls_ctx_initialised(struct tls_root_ctx *ctx)
{
ASSERT(NULL != ctx);
return ctx->initialised;
}
void
tls_ctx_set_options (struct tls_root_ctx *ctx, unsigned int ssl_flags)
{
}
void
tls_ctx_restrict_ciphers(struct tls_root_ctx *ctx, const char *ciphers)
{
char *tmp_ciphers, *tmp_ciphers_orig, *token;
int i, cipher_count;
int ciphers_len = strlen (ciphers);
ASSERT (NULL != ctx);
ASSERT (0 != ciphers_len);
/* Get number of ciphers */
for (i = 0, cipher_count = 1; i < ciphers_len; i++)
if (ciphers[i] == ':')
cipher_count++;
/* Allocate an array for them */
ALLOC_ARRAY_CLEAR(ctx->allowed_ciphers, int, cipher_count+1)
/* Parse allowed ciphers, getting IDs */
i = 0;
tmp_ciphers_orig = tmp_ciphers = strdup(ciphers);
token = strtok (tmp_ciphers, ":");
while(token)
{
ctx->allowed_ciphers[i] = ssl_get_ciphersuite_id (token);
if (0 != ctx->allowed_ciphers[i])
i++;
token = strtok (NULL, ":");
}
free(tmp_ciphers_orig);
}
void
tls_ctx_load_dh_params (struct tls_root_ctx *ctx, const char *dh_file
#if ENABLE_INLINE_FILES
, const char *dh_file_inline
#endif /* ENABLE_INLINE_FILES */
)
{
#if ENABLE_INLINE_FILES
if (!strcmp (dh_file, INLINE_FILE_TAG) && dh_file_inline)
{
if (0 != x509parse_dhm(ctx->dhm_ctx, dh_file_inline, strlen(dh_file_inline)))
msg (M_FATAL, "Cannot read inline DH parameters");
}
else
#endif /* ENABLE_INLINE_FILES */
{
if (0 != x509parse_dhmfile(ctx->dhm_ctx, dh_file))
msg (M_FATAL, "Cannot read DH parameters from file %s", dh_file);
}
msg (D_TLS_DEBUG_LOW, "Diffie-Hellman initialized with " counter_format " bit key",
(counter_type) 8 * mpi_size(&ctx->dhm_ctx->P));
}
int
tls_ctx_load_pkcs12(struct tls_root_ctx *ctx, const char *pkcs12_file,
#if ENABLE_INLINE_FILES
const char *pkcs12_file_inline,
#endif /* ENABLE_INLINE_FILES */
bool load_ca_file
)
{
msg(M_FATAL, "PKCS #12 files not yet supported for PolarSSL.");
return 0;
}
#ifdef ENABLE_CRYPTOAPI
void
tls_ctx_load_cryptoapi(struct tls_root_ctx *ctx, const char *cryptoapi_cert)
{
msg(M_FATAL, "Windows CryptoAPI not yet supported for PolarSSL.");
}
#endif /* WIN32 */
void
tls_ctx_load_cert_file (struct tls_root_ctx *ctx, const char *cert_file,
#if ENABLE_INLINE_FILES
const char *cert_file_inline,
#endif
x509_cert_t **x509
)
{
ASSERT(NULL != ctx);
if (NULL != x509)
ASSERT(NULL == *x509);
#if ENABLE_INLINE_FILES
if (!strcmp (cert_file, INLINE_FILE_TAG) && cert_file_inline)
{
if (0 != x509parse_crt(ctx->crt_chain, cert_file_inline,
strlen(cert_file_inline)))
msg (M_FATAL, "Cannot load inline certificate file");
}
else
#endif /* ENABLE_INLINE_FILES */
{
if (0 != x509parse_crtfile(ctx->crt_chain, cert_file))
msg (M_FATAL, "Cannot load certificate file %s", cert_file);
}
if (x509)
{
*x509 = ctx->crt_chain;
}
}
void
tls_ctx_free_cert_file (x509_cert_t *x509)
{
x509_free(x509);
}
int
tls_ctx_load_priv_file (struct tls_root_ctx *ctx, const char *priv_key_file
#if ENABLE_INLINE_FILES
, const char *priv_key_file_inline
#endif /* ENABLE_INLINE_FILES */
)
{
int status;
ASSERT(NULL != ctx);
#if ENABLE_INLINE_FILES
if (!strcmp (priv_key_file, INLINE_FILE_TAG) && priv_key_file_inline)
{
status = x509parse_key(ctx->priv_key,
priv_key_file_inline, strlen(priv_key_file_inline),
NULL, 0);
if (POLARSSL_ERR_PEM_PASSWORD_REQUIRED == status)
{
char passbuf[512] = {0};
pem_password_callback(passbuf, 512, 0, NULL);
status = x509parse_key(ctx->priv_key,
priv_key_file_inline, strlen(priv_key_file_inline),
passbuf, strlen(passbuf));
}
}
else
#endif /* ENABLE_INLINE_FILES */
{
status = x509parse_keyfile(ctx->priv_key, priv_key_file, NULL);
if (POLARSSL_ERR_PEM_PASSWORD_REQUIRED == status)
{
char passbuf[512] = {0};
pem_password_callback(passbuf, 512, 0, NULL);
status = x509parse_keyfile(ctx->priv_key, priv_key_file, passbuf);
}
}
if (0 != status)
{
#ifdef ENABLE_MANAGEMENT
if (management && (POLARSSL_ERR_PEM_PASSWORD_MISMATCH == status))
management_auth_failure (management, UP_TYPE_PRIVATE_KEY, NULL);
#endif
msg (M_WARN, "Cannot load private key file %s", priv_key_file);
return 1;
}
warn_if_group_others_accessible (priv_key_file);
/* TODO: Check Private Key */
// if (!SSL_CTX_check_private_key (ctx))
// msg (M_SSLERR, "Private key does not match the certificate");
return 0;
}
#ifdef MANAGMENT_EXTERNAL_KEY
int
tls_ctx_use_external_private_key (struct tls_root_ctx *ctx, x509_cert_t *cert)
{
msg(M_FATAL, "Use of management external keys not yet supported for PolarSSL.");
return false;
}
#endif
void tls_ctx_load_ca (struct tls_root_ctx *ctx, const char *ca_file,
#if ENABLE_INLINE_FILES
const char *ca_file_inline,
#endif
const char *ca_path, bool tls_server
)
{
if (ca_path)
msg(M_FATAL, "ERROR: PolarSSL cannot handle the capath directive");
#if ENABLE_INLINE_FILES
if (ca_file && !strcmp (ca_file, INLINE_FILE_TAG) && ca_file_inline)
{
if (0 != x509parse_crt(ctx->ca_chain, ca_file_inline, strlen(ca_file_inline)));
msg (M_FATAL, "Cannot load inline CA certificates");
}
else
#endif
{
/* Load CA file for verifying peer supplied certificate */
if (0 != x509parse_crtfile(ctx->ca_chain, ca_file))
msg (M_FATAL, "Cannot load CA certificate file %s", ca_file);
}
}
void
tls_ctx_load_extra_certs (struct tls_root_ctx *ctx, const char *extra_certs_file
#if ENABLE_INLINE_FILES
, const char *extra_certs_file_inline
#endif
)
{
ASSERT(NULL != ctx);
#if ENABLE_INLINE_FILES
if (!strcmp (extra_certs_file, INLINE_FILE_TAG) && extra_certs_file_inline)
{
if (0 != x509parse_crt(ctx->crt_chain, extra_certs_file_inline,
strlen(extra_certs_file_inline)))
msg (M_FATAL, "Cannot load inline extra-certs file");
}
else
#endif /* ENABLE_INLINE_FILES */
{
if (0 != x509parse_crtfile(ctx->crt_chain, extra_certs_file))
msg (M_FATAL, "Cannot load extra-certs file: %s", extra_certs_file);
}
}
/* **************************************
*
* Key-state specific functions
*
***************************************/
/*
* "Endless buffer"
*/
static inline void buf_free_entry(buffer_entry *entry)
{
if (NULL != entry)
{
free(entry->data);
free(entry);
}
}
static void buf_free_entries(endless_buffer *buf)
{
while(buf->first_block)
{
buffer_entry *cur_block = buf->first_block;
buf->first_block = cur_block->next_block;
buf_free_entry(cur_block);
}
buf->last_block = NULL;
}
static int endless_buf_read( void * ctx, unsigned char * out, size_t out_len )
{
endless_buffer *in = (endless_buffer *) ctx;
size_t read_len = 0;
if (in->first_block == NULL)
return POLARSSL_ERR_NET_WANT_READ;
while (in->first_block != NULL && read_len < out_len)
{
int block_len = in->first_block->length - in->data_start;
if (block_len <= out_len - read_len)
{
buffer_entry *cur_entry = in->first_block;
memcpy(out + read_len, cur_entry->data + in->data_start,
block_len);
read_len += block_len;
in->first_block = cur_entry->next_block;
in->data_start = 0;
if (in->first_block == NULL)
in->last_block = NULL;
buf_free_entry(cur_entry);
}
else
{
memcpy(out + read_len, in->first_block->data + in->data_start,
out_len - read_len);
in->data_start += out_len - read_len;
read_len = out_len;
}
}
return read_len;
}
static int endless_buf_write( void *ctx, const unsigned char *in, size_t len )
{
endless_buffer *out = (endless_buffer *) ctx;
buffer_entry *new_block = malloc(sizeof(buffer_entry));
if (NULL == new_block)
return POLARSSL_ERR_NET_SEND_FAILED;
new_block->data = malloc(len);
if (NULL == new_block->data)
{
free(new_block);
return POLARSSL_ERR_NET_SEND_FAILED;
}
new_block->length = len;
new_block->next_block = NULL;
memcpy(new_block->data, in, len);
if (NULL == out->first_block)
out->first_block = new_block;
if (NULL != out->last_block)
out->last_block->next_block = new_block;
out->last_block = new_block;
return len;
}
static void my_debug( void *ctx, int level, const char *str )
{
if (level == 1)
{
dmsg (D_HANDSHAKE_VERBOSE, "PolarSSL alert: %s", str);
}
}
void key_state_ssl_init(struct key_state_ssl *ks_ssl,
const struct tls_root_ctx *ssl_ctx, bool is_server, void *session)
{
ASSERT(NULL != ssl_ctx);
ASSERT(ks_ssl);
CLEAR(*ks_ssl);
ALLOC_OBJ_CLEAR(ks_ssl->ctx, ssl_context);
if (0 == ssl_init(ks_ssl->ctx))
{
/* Initialise SSL context */
ssl_set_dbg (ks_ssl->ctx, my_debug, NULL);
ssl_set_endpoint (ks_ssl->ctx, ssl_ctx->endpoint);
ssl_set_rng (ks_ssl->ctx, havege_rand, ssl_ctx->hs);
ALLOC_OBJ_CLEAR (ks_ssl->ssn, ssl_session);
ssl_set_session (ks_ssl->ctx, 0, 0, ks_ssl->ssn );
if (ssl_ctx->allowed_ciphers)
ssl_set_ciphersuites (ks_ssl->ctx, ssl_ctx->allowed_ciphers);
else
ssl_set_ciphersuites (ks_ssl->ctx, default_ciphersuites);
/* Initialise authentication information */
if (is_server)
ssl_set_dh_param_ctx (ks_ssl->ctx, ssl_ctx->dhm_ctx );
#if defined(ENABLE_PKCS11)
if (ssl_ctx->priv_key_pkcs11 != NULL)
ssl_set_own_cert_pkcs11( ks_ssl->ctx, ssl_ctx->crt_chain,
ssl_ctx->priv_key_pkcs11 );
else
#endif
ssl_set_own_cert( ks_ssl->ctx, ssl_ctx->crt_chain, ssl_ctx->priv_key );
/* Initialise SSL verification */
ssl_set_authmode (ks_ssl->ctx, SSL_VERIFY_REQUIRED);
ssl_set_verify (ks_ssl->ctx, verify_callback, session);
/* TODO: PolarSSL does not currently support sending the CA chain to the client */
ssl_set_ca_chain (ks_ssl->ctx, ssl_ctx->ca_chain, NULL, NULL );
/* Initialise BIOs */
ALLOC_OBJ_CLEAR (ks_ssl->ct_in, endless_buffer);
ALLOC_OBJ_CLEAR (ks_ssl->ct_out, endless_buffer);
ssl_set_bio (ks_ssl->ctx, endless_buf_read, ks_ssl->ct_in,
endless_buf_write, ks_ssl->ct_out);
}
}
void
key_state_ssl_free(struct key_state_ssl *ks_ssl)
{
if (ks_ssl) {
if (ks_ssl->ctx)
{
ssl_free(ks_ssl->ctx);
free(ks_ssl->ctx);
}
if (ks_ssl->ssn)
free(ks_ssl->ssn);
if (ks_ssl->ct_in) {
buf_free_entries(ks_ssl->ct_in);
free(ks_ssl->ct_in);
}
if (ks_ssl->ct_out) {
buf_free_entries(ks_ssl->ct_out);
free(ks_ssl->ct_out);
}
CLEAR(*ks_ssl);
}
}
int
key_state_write_plaintext (struct key_state_ssl *ks, struct buffer *buf)
{
int retval = 0;
perf_push (PERF_BIO_WRITE_PLAINTEXT);
ASSERT (NULL != ks);
ASSERT (buf);
ASSERT (buf->len >= 0);
if (0 == buf->len)
{
return 0;
perf_pop ();
}
retval = ssl_write(ks->ctx, BPTR(buf), buf->len);
if (retval < 0)
{
perf_pop ();
if (POLARSSL_ERR_NET_WANT_WRITE == retval || POLARSSL_ERR_NET_WANT_READ == retval)
return 0;
msg (D_TLS_ERRORS, "TLS ERROR: write tls_write_plaintext error");
return -1;
}
if (retval != buf->len)
{
msg (D_TLS_ERRORS,
"TLS ERROR: write tls_write_plaintext incomplete %d/%d",
retval, buf->len);
perf_pop ();
return -1;
}
/* successful write */
dmsg (D_HANDSHAKE_VERBOSE, "write tls_write_plaintext %d bytes", retval);
memset (BPTR (buf), 0, BLEN (buf)); /* erase data just written */
buf->len = 0;
perf_pop ();
return 1;
}
int
key_state_write_plaintext_const (struct key_state_ssl *ks, const uint8_t *data, int len)
{
int retval = 0;
perf_push (PERF_BIO_WRITE_PLAINTEXT);
ASSERT (NULL != ks);
ASSERT (len >= 0);
if (0 == len)
{
perf_pop ();
return 0;
}
ASSERT (data);
retval = ssl_write(ks->ctx, data, len);
if (retval < 0)
{
perf_pop ();
if (POLARSSL_ERR_NET_WANT_WRITE == retval || POLARSSL_ERR_NET_WANT_READ == retval)
return 0;
msg (D_TLS_ERRORS, "TLS ERROR: write tls_write_plaintext_const error");
return -1;
}
if (retval != len)
{
msg (D_TLS_ERRORS,
"TLS ERROR: write tls_write_plaintext_const incomplete %d/%d",
retval, len);
perf_pop ();
return -1;
}
/* successful write */
dmsg (D_HANDSHAKE_VERBOSE, "write tls_write_plaintext_const %d bytes", retval);
perf_pop ();
return 1;
}
int
key_state_read_ciphertext (struct key_state_ssl *ks, struct buffer *buf,
int maxlen)
{
int retval = 0;
int len = 0;
perf_push (PERF_BIO_READ_CIPHERTEXT);
ASSERT (NULL != ks);
ASSERT (buf);
ASSERT (buf->len >= 0);
if (buf->len)
{
perf_pop ();
return 0;
}
len = buf_forward_capacity (buf);
if (maxlen < len)
len = maxlen;
retval = endless_buf_read(ks->ct_out, BPTR(buf), len);
/* Error during read, check for retry error */
if (retval < 0)
{
perf_pop ();
if (POLARSSL_ERR_NET_WANT_WRITE == retval || POLARSSL_ERR_NET_WANT_READ == retval)
return 0;
msg (D_TLS_ERRORS, "TLS_ERROR: read tls_read_plaintext error");
buf->len = 0;
return -1;
}
/* Nothing read, try again */
if (0 == retval)
{
buf->len = 0;
perf_pop ();
return 0;
}
/* successful read */
dmsg (D_HANDSHAKE_VERBOSE, "read tls_read_ciphertext %d bytes", retval);
buf->len = retval;
perf_pop ();
return 1;
}
int
key_state_write_ciphertext (struct key_state_ssl *ks, struct buffer *buf)
{
int retval = 0;
perf_push (PERF_BIO_WRITE_CIPHERTEXT);
ASSERT (NULL != ks);
ASSERT (buf);
ASSERT (buf->len >= 0);
if (0 == buf->len)
{
perf_pop ();
return 0;
}
retval = endless_buf_write(ks->ct_in, BPTR(buf), buf->len);
if (retval < 0)
{
perf_pop ();
if (POLARSSL_ERR_NET_WANT_WRITE == retval || POLARSSL_ERR_NET_WANT_READ == retval)
return 0;
msg (D_TLS_ERRORS, "TLS ERROR: write tls_write_ciphertext error");
return -1;
}
if (retval != buf->len)
{
msg (D_TLS_ERRORS,
"TLS ERROR: write tls_write_ciphertext incomplete %d/%d",
retval, buf->len);
perf_pop ();
return -1;
}
/* successful write */
dmsg (D_HANDSHAKE_VERBOSE, "write tls_write_ciphertext %d bytes", retval);
memset (BPTR (buf), 0, BLEN (buf)); /* erase data just written */
buf->len = 0;
perf_pop ();
return 1;
}
int
key_state_read_plaintext (struct key_state_ssl *ks, struct buffer *buf,
int maxlen)
{
int retval = 0;
int len = 0;
perf_push (PERF_BIO_READ_PLAINTEXT);
ASSERT (NULL != ks);
ASSERT (buf);
ASSERT (buf->len >= 0);
if (buf->len)
{
perf_pop ();
return 0;
}
len = buf_forward_capacity (buf);
if (maxlen < len)
len = maxlen;
retval = ssl_read(ks->ctx, BPTR(buf), len);
/* Error during read, check for retry error */
if (retval < 0)
{
if (POLARSSL_ERR_NET_WANT_WRITE == retval || POLARSSL_ERR_NET_WANT_READ == retval)
return 0;
msg (D_TLS_ERRORS, "TLS_ERROR: read tls_read_plaintext error");
buf->len = 0;
perf_pop ();
return -1;
}
/* Nothing read, try again */
if (0 == retval)
{
buf->len = 0;
perf_pop ();
return 0;
}
/* successful read */
dmsg (D_HANDSHAKE_VERBOSE, "read tls_read_plaintext %d bytes", retval);
buf->len = retval;
perf_pop ();
return 1;
}
/* **************************************
*
* Information functions
*
* Print information for the end user.
*
***************************************/
void
print_details (struct key_state_ssl * ks_ssl, const char *prefix)
{
x509_cert *cert;
char s1[256];
char s2[256];
s1[0] = s2[0] = 0;
openvpn_snprintf (s1, sizeof (s1), "%s %s, cipher %s",
prefix,
ssl_get_version (ks_ssl->ctx),
ssl_get_ciphersuite(ks_ssl->ctx));
cert = ks_ssl->ctx->peer_cert;
if (cert != NULL)
{
openvpn_snprintf (s2, sizeof (s2), ", " counter_format " bit RSA", (counter_type) cert->rsa.len * 8);
}
msg (D_HANDSHAKE, "%s%s", s1, s2);
}
void
show_available_tls_ciphers ()
{
const int *ciphers = ssl_list_ciphersuites();
#ifndef ENABLE_SMALL
printf ("Available TLS Ciphers,\n");
printf ("listed in order of preference:\n\n");
#endif
while (*ciphers != 0)
{
printf ("%s\n", ssl_get_ciphersuite_name(*ciphers));
ciphers++;
}
printf ("\n");
}
void
get_highest_preference_tls_cipher (char *buf, int size)
{
const char *cipher_name;
const int *ciphers = ssl_list_ciphersuites();
if (*ciphers == 0)
msg (M_FATAL, "Cannot retrieve list of supported SSL ciphers.");
cipher_name = ssl_get_ciphersuite_name(*ciphers);
strncpynt (buf, cipher_name, size);
}
#endif /* defined(USE_SSL) && defined(USE_POLARSSL) */