/*
* 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>
* Copyright (C) 2006-2010, Brainspark B.V.
*
* 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 mbed TLS Backend
*/
#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_MBEDTLS)
#include "errlevel.h"
#include "ssl_backend.h"
#include "base64.h"
#include "buffer.h"
#include "misc.h"
#include "manage.h"
#include "ssl_common.h"
#include <mbedtls/havege.h>
#include "ssl_verify_mbedtls.h"
#include <mbedtls/debug.h>
#include <mbedtls/error.h>
#include <mbedtls/net.h>
#include <mbedtls/oid.h>
#include <mbedtls/pem.h>
#include <mbedtls/sha256.h>
#include <mbedtls/version.h>
void
tls_init_lib()
{
}
void
tls_free_lib()
{
}
void
tls_clear_error()
{
}
void
tls_ctx_server_new(struct tls_root_ctx *ctx)
{
ASSERT(NULL != ctx);
CLEAR(*ctx);
ALLOC_OBJ_CLEAR(ctx->dhm_ctx, mbedtls_dhm_context);
ALLOC_OBJ_CLEAR(ctx->ca_chain, mbedtls_x509_crt);
ctx->endpoint = MBEDTLS_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->dhm_ctx, mbedtls_dhm_context);
ALLOC_OBJ_CLEAR(ctx->ca_chain, mbedtls_x509_crt);
ctx->endpoint = MBEDTLS_SSL_IS_CLIENT;
ctx->initialised = true;
}
void
tls_ctx_free(struct tls_root_ctx *ctx)
{
if (ctx)
{
mbedtls_pk_free(ctx->priv_key);
if (ctx->priv_key)
free(ctx->priv_key);
mbedtls_x509_crt_free(ctx->ca_chain);
if (ctx->ca_chain)
free(ctx->ca_chain);
mbedtls_x509_crt_free(ctx->crt_chain);
if (ctx->crt_chain)
free(ctx->crt_chain);
mbedtls_dhm_free(ctx->dhm_ctx);
if (ctx->dhm_ctx)
free(ctx->dhm_ctx);
#if defined(ENABLE_PKCS11)
if (ctx->priv_key_pkcs11 != NULL) {
mbedtls_pkcs11_priv_key_free(ctx->priv_key_pkcs11);
free(ctx->priv_key_pkcs11);
}
#endif
#if defined(MANAGMENT_EXTERNAL_KEY)
if (ctx->external_key != NULL)
free(ctx->external_key);
#endif
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
key_state_export_keying_material(struct key_state_ssl *ssl,
struct tls_session *session)
{
}
void
tls_ctx_set_options (struct tls_root_ctx *ctx, unsigned int ssl_flags)
{
}
static const char *
tls_translate_cipher_name (const char * cipher_name) {
const tls_cipher_name_pair * pair = tls_get_cipher_name_pair(cipher_name, strlen(cipher_name));
if (NULL == pair)
{
// No translation found, return original
return cipher_name;
}
if (0 != strcmp(cipher_name, pair->iana_name))
{
// Deprecated name found, notify user
msg(M_WARN, "Deprecated cipher suite name '%s', please use IANA name '%s'", pair->openssl_name, pair->iana_name);
}
return pair->iana_name;
}
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;
if (NULL == ciphers)
return; /* Nothing to do */
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 = string_alloc (ciphers, NULL);
token = strtok (tmp_ciphers, ":");
while(token)
{
ctx->allowed_ciphers[i] = mbedtls_ssl_get_ciphersuite_id (
tls_translate_cipher_name (token));
if (0 != ctx->allowed_ciphers[i])
i++;
token = strtok (NULL, ":");
}
free(tmp_ciphers_orig);
}
void
tls_ctx_check_cert_time (const struct tls_root_ctx *ctx)
{
ASSERT (ctx);
if (ctx->crt_chain == NULL)
{
return; /* Nothing to check if there is no certificate */
}
if (mbedtls_x509_time_is_future (&ctx->crt_chain->valid_from))
{
msg (M_WARN, "WARNING: Your certificate is not yet valid!");
}
if (mbedtls_x509_time_is_past (&ctx->crt_chain->valid_to))
{
msg (M_WARN, "WARNING: Your certificate has expired!");
}
}
void
tls_ctx_load_dh_params (struct tls_root_ctx *ctx, const char *dh_file,
const char *dh_inline
)
{
if (!strcmp (dh_file, INLINE_FILE_TAG) && dh_inline)
{
if (!mbed_ok(mbedtls_dhm_parse_dhm(ctx->dhm_ctx,
(const unsigned char *) dh_inline, strlen(dh_inline)+1)))
msg (M_FATAL, "Cannot read inline DH parameters");
}
else
{
if (!mbed_ok(mbedtls_dhm_parse_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 * mbedtls_mpi_size(&ctx->dhm_ctx->P));
}
void
tls_ctx_load_ecdh_params (struct tls_root_ctx *ctx, const char *curve_name
)
{
if (NULL != curve_name)
msg(M_WARN, "WARNING: mbed TLS builds do not support specifying an ECDH "
"curve, using default curves.");
}
int
tls_ctx_load_pkcs12(struct tls_root_ctx *ctx, const char *pkcs12_file,
const char *pkcs12_file_inline,
bool load_ca_file
)
{
msg(M_FATAL, "PKCS #12 files not yet supported for mbed TLS.");
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 mbed TLS.");
}
#endif /* _WIN32 */
void
tls_ctx_load_cert_file (struct tls_root_ctx *ctx, const char *cert_file,
const char *cert_inline
)
{
ASSERT(NULL != ctx);
if (!ctx->crt_chain)
{
ALLOC_OBJ_CLEAR(ctx->crt_chain, mbedtls_x509_crt);
}
if (!strcmp (cert_file, INLINE_FILE_TAG) && cert_inline)
{
if (!mbed_ok(mbedtls_x509_crt_parse(ctx->crt_chain,
(const unsigned char *) cert_inline, strlen(cert_inline)+1)))
msg (M_FATAL, "Cannot load inline certificate file");
}
else
{
if (!mbed_ok(mbedtls_x509_crt_parse_file(ctx->crt_chain, cert_file)))
{
msg (M_FATAL, "Cannot load certificate file %s", cert_file);
}
}
}
int
tls_ctx_load_priv_file (struct tls_root_ctx *ctx, const char *priv_key_file,
const char *priv_key_inline
)
{
int status;
ASSERT(NULL != ctx);
if (!ctx->priv_key)
{
ALLOC_OBJ_CLEAR(ctx->priv_key, mbedtls_pk_context);
}
if (!strcmp (priv_key_file, INLINE_FILE_TAG) && priv_key_inline)
{
status = mbedtls_pk_parse_key(ctx->priv_key,
(const unsigned char *) priv_key_inline, strlen(priv_key_inline)+1,
NULL, 0);
if (MBEDTLS_ERR_PK_PASSWORD_REQUIRED == status)
{
char passbuf[512] = {0};
pem_password_callback(passbuf, 512, 0, NULL);
status = mbedtls_pk_parse_key(ctx->priv_key,
(const unsigned char *) priv_key_inline,
strlen(priv_key_inline)+1, (unsigned char *) passbuf,
strlen(passbuf));
}
}
else
{
status = mbedtls_pk_parse_keyfile(ctx->priv_key, priv_key_file, NULL);
if (MBEDTLS_ERR_PK_PASSWORD_REQUIRED == status)
{
char passbuf[512] = {0};
pem_password_callback(passbuf, 512, 0, NULL);
status = mbedtls_pk_parse_keyfile(ctx->priv_key, priv_key_file, passbuf);
}
}
if (!mbed_ok(status))
{
#ifdef ENABLE_MANAGEMENT
if (management && (MBEDTLS_ERR_PK_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;
}
if (!mbed_ok(mbedtls_pk_check_pair(&ctx->crt_chain->pk, ctx->priv_key)))
{
msg (M_WARN, "Private key does not match the certificate");
return 1;
}
return 0;
}
#ifdef MANAGMENT_EXTERNAL_KEY
struct external_context {
size_t signature_length;
};
/**
* external_pkcs1_sign implements a mbed TLS rsa_sign_func callback, that uses
* the management interface to request an RSA signature for the supplied hash.
*
* @param ctx_voidptr Management external key context.
* @param f_rng (Unused)
* @param p_rng (Unused)
* @param mode RSA mode (should be RSA_PRIVATE).
* @param md_alg Message digest ('hash') algorithm type.
* @param hashlen Length of hash (overridden by length specified by md_alg
* if md_alg != MBEDTLS_MD_NONE).
* @param hash The digest ('hash') to sign. Should have a size
* matching the length of md_alg (if != MBEDTLS_MD_NONE),
* or hashlen otherwise.
* @param sig Buffer that returns the signature. Should be at least of
* size ctx->signature_length.
*
* @return 0 on success, non-zero mbed TLS error code on failure.
*/
static inline int external_pkcs1_sign( void *ctx_voidptr,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, int mode,
mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash,
unsigned char *sig )
{
struct external_context * const ctx = ctx_voidptr;
char *in_b64 = NULL;
char *out_b64 = NULL;
int rv;
unsigned char *p = sig;
size_t asn_len = 0, oid_size = 0, sig_len = 0;
const char *oid = NULL;
if( NULL == ctx )
return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
if( MBEDTLS_RSA_PRIVATE != mode )
return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
/*
* Support a wide range of hashes. TLSv1.1 and before only need SIG_RSA_RAW,
* but TLSv1.2 needs the full suite of hashes.
*
* This code has been taken from mbed TLS pkcs11_sign(), under the GPLv2.0+.
*/
if( md_alg != MBEDTLS_MD_NONE )
{
const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_alg );
if( md_info == NULL )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
if (!mbed_ok(mbedtls_oid_get_oid_by_md( md_alg, &oid, &oid_size )))
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
hashlen = mbedtls_md_get_size( md_info );
asn_len = 10 + oid_size;
}
sig_len = ctx->signature_length;
if ( (SIZE_MAX - hashlen) < asn_len || (hashlen + asn_len) > sig_len )
return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
if( md_alg != MBEDTLS_MD_NONE )
{
/*
* DigestInfo ::= SEQUENCE {
* digestAlgorithm DigestAlgorithmIdentifier,
* digest Digest }
*
* DigestAlgorithmIdentifier ::= AlgorithmIdentifier
*
* Digest ::= OCTET STRING
*/
*p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
*p++ = (unsigned char) ( 0x08 + oid_size + hashlen );
*p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
*p++ = (unsigned char) ( 0x04 + oid_size );
*p++ = MBEDTLS_ASN1_OID;
*p++ = oid_size & 0xFF;
memcpy( p, oid, oid_size );
p += oid_size;
*p++ = MBEDTLS_ASN1_NULL;
*p++ = 0x00;
*p++ = MBEDTLS_ASN1_OCTET_STRING;
*p++ = hashlen;
/* Determine added ASN length */
asn_len = p - sig;
}
/* Copy the hash to be signed */
memcpy( p, hash, hashlen );
/* convert 'from' to base64 */
if (openvpn_base64_encode (sig, asn_len + hashlen, &in_b64) <= 0)
{
rv = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
goto done;
}
/* call MI for signature */
if (management)
out_b64 = management_query_rsa_sig (management, in_b64);
if (!out_b64)
{
rv = MBEDTLS_ERR_RSA_PRIVATE_FAILED;
goto done;
}
/* decode base64 signature to binary and verify length */
if ( openvpn_base64_decode (out_b64, sig, ctx->signature_length) !=
ctx->signature_length )
{
rv = MBEDTLS_ERR_RSA_PRIVATE_FAILED;
goto done;
}
rv = 0;
done:
if (in_b64)
free (in_b64);
if (out_b64)
free (out_b64);
return rv;
}
static inline size_t external_key_len(void *vctx)
{
struct external_context * const ctx = vctx;
return ctx->signature_length;
}
int
tls_ctx_use_external_private_key (struct tls_root_ctx *ctx,
const char *cert_file, const char *cert_file_inline)
{
ASSERT(NULL != ctx);
tls_ctx_load_cert_file(ctx, cert_file, cert_file_inline);
if (ctx->crt_chain == NULL)
return 0;
ALLOC_OBJ_CLEAR (ctx->external_key, struct external_context);
ctx->external_key->signature_length = mbedtls_pk_get_len (&ctx->crt_chain->pk);
ALLOC_OBJ_CLEAR (ctx->priv_key, mbedtls_pk_context);
if (!mbed_ok (mbedtls_pk_setup_rsa_alt (ctx->priv_key, ctx->external_key,
NULL, external_pkcs1_sign, external_key_len)))
return 0;
return 1;
}
#endif
void tls_ctx_load_ca (struct tls_root_ctx *ctx, const char *ca_file,
const char *ca_inline, const char *ca_path, bool tls_server
)
{
if (ca_path)
msg(M_FATAL, "ERROR: mbed TLS cannot handle the capath directive");
if (ca_file && !strcmp (ca_file, INLINE_FILE_TAG) && ca_inline)
{
if (!mbed_ok (mbedtls_x509_crt_parse (ctx->ca_chain,
(const unsigned char *) ca_inline, strlen(ca_inline)+1)))
msg (M_FATAL, "Cannot load inline CA certificates");
}
else
{
/* Load CA file for verifying peer supplied certificate */
if (!mbed_ok (mbedtls_x509_crt_parse_file (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,
const char *extra_certs_inline
)
{
ASSERT(NULL != ctx);
if (!ctx->crt_chain)
{
ALLOC_OBJ_CLEAR (ctx->crt_chain, mbedtls_x509_crt);
}
if (!strcmp (extra_certs_file, INLINE_FILE_TAG) && extra_certs_inline)
{
if (!mbed_ok(mbedtls_x509_crt_parse(ctx->crt_chain,
(const unsigned char *) extra_certs_inline,
strlen(extra_certs_inline)+1)))
msg (M_FATAL, "Cannot load inline extra-certs file");
}
else
{
if (!mbed_ok(mbedtls_x509_crt_parse_file(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( endless_buffer *in, unsigned char * out, size_t out_len )
{
size_t read_len = 0;
if (in->first_block == NULL)
return MBEDTLS_ERR_SSL_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( endless_buffer *out, const unsigned char *in, size_t len )
{
buffer_entry *new_block = malloc(sizeof(buffer_entry));
if (NULL == new_block)
return MBEDTLS_ERR_NET_SEND_FAILED;
new_block->data = malloc(len);
if (NULL == new_block->data)
{
free(new_block);
return MBEDTLS_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 int ssl_bio_read( void *ctx, unsigned char *out, size_t out_len)
{
bio_ctx *my_ctx = (bio_ctx *) ctx;
return endless_buf_read (&my_ctx->in, out, out_len);
}
static int ssl_bio_write( void *ctx, const unsigned char *in, size_t in_len)
{
bio_ctx *my_ctx = (bio_ctx *) ctx;
return endless_buf_write (&my_ctx->out, in, in_len);
}
static void my_debug( void *ctx, int level, const char *file, int line,
const char *str )
{
int my_loglevel = (level < 3) ? D_TLS_DEBUG_MED : D_TLS_DEBUG;
msg (my_loglevel, "mbed TLS msg (%s:%d): %s", file, line, str);
}
/*
* Further personalise the RNG using a hash of the public key
*/
void tls_ctx_personalise_random(struct tls_root_ctx *ctx)
{
static char old_sha256_hash[32] = {0};
unsigned char sha256_hash[32] = {0};
mbedtls_ctr_drbg_context *cd_ctx = rand_ctx_get();
if (NULL != ctx->crt_chain)
{
mbedtls_x509_crt *cert = ctx->crt_chain;
mbedtls_sha256(cert->tbs.p, cert->tbs.len, sha256_hash, false);
if ( 0 != memcmp(old_sha256_hash, sha256_hash, sizeof(sha256_hash)))
{
mbedtls_ctr_drbg_update(cd_ctx, sha256_hash, 32);
memcpy(old_sha256_hash, sha256_hash, sizeof(old_sha256_hash));
}
}
}
int
tls_version_max(void)
{
#if defined(MBEDTLS_SSL_MAJOR_VERSION_3) && defined(MBEDTLS_SSL_MINOR_VERSION_3)
return TLS_VER_1_2;
#elif defined(MBEDTLS_SSL_MAJOR_VERSION_3) && defined(MBEDTLS_SSL_MINOR_VERSION_2)
return TLS_VER_1_1;
#else
return TLS_VER_1_0;
#endif
}
/**
* Convert an OpenVPN tls-version variable to mbed TLS format (i.e. a major and
* minor ssl version number).
*
* @param tls_ver The tls-version variable to convert.
* @param major Returns the TLS major version in mbed TLS format.
* Must be a valid pointer.
* @param minor Returns the TLS minor version in mbed TLS format.
* Must be a valid pointer.
*/
static void tls_version_to_major_minor(int tls_ver, int *major, int *minor) {
ASSERT(major);
ASSERT(minor);
switch (tls_ver)
{
case TLS_VER_1_0:
*major = MBEDTLS_SSL_MAJOR_VERSION_3;
*minor = MBEDTLS_SSL_MINOR_VERSION_1;
break;
case TLS_VER_1_1:
*major = MBEDTLS_SSL_MAJOR_VERSION_3;
*minor = MBEDTLS_SSL_MINOR_VERSION_2;
break;
case TLS_VER_1_2:
*major = MBEDTLS_SSL_MAJOR_VERSION_3;
*minor = MBEDTLS_SSL_MINOR_VERSION_3;
break;
default:
msg(M_FATAL, "%s: invalid TLS version %d", __func__, tls_ver);
break;
}
}
void key_state_ssl_init(struct key_state_ssl *ks_ssl,
const struct tls_root_ctx *ssl_ctx, bool is_server, struct tls_session *session)
{
ASSERT(NULL != ssl_ctx);
ASSERT(ks_ssl);
CLEAR(*ks_ssl);
/* Initialise SSL config */
mbedtls_ssl_config_init(&ks_ssl->ssl_config);
mbedtls_ssl_config_defaults(&ks_ssl->ssl_config, ssl_ctx->endpoint,
MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT);
#ifdef MBEDTLS_DEBUG_C
mbedtls_debug_set_threshold(3);
#endif
mbedtls_ssl_conf_dbg (&ks_ssl->ssl_config, my_debug, NULL);
mbedtls_ssl_conf_rng (&ks_ssl->ssl_config, mbedtls_ctr_drbg_random,
rand_ctx_get());
if (ssl_ctx->allowed_ciphers)
mbedtls_ssl_conf_ciphersuites (&ks_ssl->ssl_config, ssl_ctx->allowed_ciphers);
/* Disable record splitting (for now). OpenVPN assumes records are sent
* unfragmented, and changing that will require thorough review and
* testing. Since OpenVPN is not susceptible to BEAST, we can just
* disable record splitting as a quick fix. */
#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
mbedtls_ssl_conf_cbc_record_splitting (&ks_ssl->ssl_config,
MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED);
#endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */
/* Initialise authentication information */
if (is_server)
mbed_ok (mbedtls_ssl_conf_dh_param_ctx(&ks_ssl->ssl_config,
ssl_ctx->dhm_ctx));
mbed_ok (mbedtls_ssl_conf_own_cert(&ks_ssl->ssl_config, ssl_ctx->crt_chain,
ssl_ctx->priv_key));
/* Initialise SSL verification */
#if P2MP_SERVER
if (session->opt->ssl_flags & SSLF_CLIENT_CERT_OPTIONAL)
{
mbedtls_ssl_conf_authmode(&ks_ssl->ssl_config, MBEDTLS_SSL_VERIFY_OPTIONAL);
}
else if (!(session->opt->ssl_flags & SSLF_CLIENT_CERT_NOT_REQUIRED))
#endif
{
mbedtls_ssl_conf_authmode (&ks_ssl->ssl_config, MBEDTLS_SSL_VERIFY_REQUIRED);
}
mbedtls_ssl_conf_verify (&ks_ssl->ssl_config, verify_callback, session);
/* TODO: mbed TLS does not currently support sending the CA chain to the client */
mbedtls_ssl_conf_ca_chain (&ks_ssl->ssl_config, ssl_ctx->ca_chain, NULL );
/* Initialize minimum TLS version */
{
const int tls_version_min =
(session->opt->ssl_flags >> SSLF_TLS_VERSION_MIN_SHIFT) &
SSLF_TLS_VERSION_MIN_MASK;
/* default to TLS 1.0 */
int major = MBEDTLS_SSL_MAJOR_VERSION_3;
int minor = MBEDTLS_SSL_MINOR_VERSION_1;
if (tls_version_min > TLS_VER_UNSPEC)
tls_version_to_major_minor(tls_version_min, &major, &minor);
mbedtls_ssl_conf_min_version(&ks_ssl->ssl_config, major, minor);
}
/* Initialize maximum TLS version */
{
const int tls_version_max =
(session->opt->ssl_flags >> SSLF_TLS_VERSION_MAX_SHIFT) &
SSLF_TLS_VERSION_MAX_MASK;
if (tls_version_max > TLS_VER_UNSPEC)
{
int major, minor;
tls_version_to_major_minor(tls_version_max, &major, &minor);
mbedtls_ssl_conf_max_version(&ks_ssl->ssl_config, major, minor);
}
}
/* Initialise SSL context */
ALLOC_OBJ_CLEAR(ks_ssl->ctx, mbedtls_ssl_context);
mbedtls_ssl_init(ks_ssl->ctx);
mbedtls_ssl_setup(ks_ssl->ctx, &ks_ssl->ssl_config);
/* Initialise BIOs */
CLEAR (ks_ssl->bio_ctx);
mbedtls_ssl_set_bio (ks_ssl->ctx, &ks_ssl->bio_ctx, ssl_bio_write,
ssl_bio_read, NULL);
}
void
key_state_ssl_free(struct key_state_ssl *ks_ssl)
{
if (ks_ssl) {
if (ks_ssl->ctx)
{
mbedtls_ssl_free(ks_ssl->ctx);
free(ks_ssl->ctx);
}
mbedtls_ssl_config_free(&ks_ssl->ssl_config);
buf_free_entries(&ks_ssl->bio_ctx.in);
buf_free_entries(&ks_ssl->bio_ctx.out);
CLEAR(*ks_ssl);
}
}
int
key_state_write_plaintext (struct key_state_ssl *ks, struct buffer *buf)
{
int retval = 0;
ASSERT (buf);
retval = key_state_write_plaintext_const(ks, BPTR(buf), BLEN(buf));
if (1 == retval)
{
memset (BPTR (buf), 0, BLEN (buf)); /* erase data just written */
buf->len = 0;
}
return retval;
}
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 = mbedtls_ssl_write(ks->ctx, data, len);
if (retval < 0)
{
perf_pop ();
if (MBEDTLS_ERR_SSL_WANT_WRITE == retval || MBEDTLS_ERR_SSL_WANT_READ == retval)
return 0;
mbed_log_err (D_TLS_ERRORS, retval,
"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->bio_ctx.out, BPTR(buf), len);
/* Error during read, check for retry error */
if (retval < 0)
{
perf_pop ();
if (MBEDTLS_ERR_SSL_WANT_WRITE == retval || MBEDTLS_ERR_SSL_WANT_READ == retval)
return 0;
mbed_log_err (D_TLS_ERRORS, retval, "TLS_ERROR: read tls_read_ciphertext 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->bio_ctx.in, BPTR(buf), buf->len);
if (retval < 0)
{
perf_pop ();
if (MBEDTLS_ERR_SSL_WANT_WRITE == retval || MBEDTLS_ERR_SSL_WANT_READ == retval)
return 0;
mbed_log_err (D_TLS_ERRORS, retval,
"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 = mbedtls_ssl_read(ks->ctx, BPTR(buf), len);
/* Error during read, check for retry error */
if (retval < 0)
{
if (MBEDTLS_ERR_SSL_WANT_WRITE == retval || MBEDTLS_ERR_SSL_WANT_READ == retval)
return 0;
mbed_log_err (D_TLS_ERRORS, retval, "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)
{
const mbedtls_x509_crt *cert;
char s1[256];
char s2[256];
s1[0] = s2[0] = 0;
openvpn_snprintf (s1, sizeof (s1), "%s %s, cipher %s",
prefix,
mbedtls_ssl_get_version (ks_ssl->ctx),
mbedtls_ssl_get_ciphersuite (ks_ssl->ctx));
cert = mbedtls_ssl_get_peer_cert (ks_ssl->ctx);
if (cert != NULL)
{
openvpn_snprintf (s2, sizeof (s2), ", %u bit key",
(unsigned int) mbedtls_pk_get_bitlen (&cert->pk));
}
msg (D_HANDSHAKE, "%s%s", s1, s2);
}
void
show_available_tls_ciphers (const char *cipher_list)
{
struct tls_root_ctx tls_ctx;
const int *ciphers = mbedtls_ssl_list_ciphersuites ();
tls_ctx_server_new(&tls_ctx);
tls_ctx_restrict_ciphers(&tls_ctx, cipher_list);
if (tls_ctx.allowed_ciphers)
ciphers = tls_ctx.allowed_ciphers;
#ifndef ENABLE_SMALL
printf ("Available TLS Ciphers,\n");
printf ("listed in order of preference:\n\n");
#endif
while (*ciphers != 0)
{
printf ("%s\n", mbedtls_ssl_get_ciphersuite_name (*ciphers));
ciphers++;
}
printf ("\n" SHOW_TLS_CIPHER_LIST_WARNING);
tls_ctx_free(&tls_ctx);
}
void
show_available_curves (void)
{
const mbedtls_ecp_curve_info *pcurve = mbedtls_ecp_curve_list ();
if (NULL == pcurve)
msg (M_FATAL, "Cannot retrieve curve list from mbed TLS");
/* Print curve list */
printf ("Available Elliptic curves, listed in order of preference:\n\n");
while (MBEDTLS_ECP_DP_NONE != pcurve->grp_id)
{
printf("%s\n", pcurve->name);
pcurve++;
}
}
void
get_highest_preference_tls_cipher (char *buf, int size)
{
const char *cipher_name;
const int *ciphers = mbedtls_ssl_list_ciphersuites();
if (*ciphers == 0)
msg (M_FATAL, "Cannot retrieve list of supported SSL ciphers.");
cipher_name = mbedtls_ssl_get_ciphersuite_name(*ciphers);
strncpynt (buf, cipher_name, size);
}
const char *
get_ssl_library_version(void)
{
static char mbedtls_version[30];
unsigned int pv = mbedtls_version_get_number();
sprintf( mbedtls_version, "mbed TLS %d.%d.%d",
(pv>>24)&0xff, (pv>>16)&0xff, (pv>>8)&0xff );
return mbedtls_version;
}
#endif /* defined(ENABLE_CRYPTO) && defined(ENABLE_CRYPTO_MBEDTLS) */