solanum-vs-hackint-and-char.../libratbox/src/mbedtls.c

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/*
* libratbox: a library used by ircd-ratbox and other things
* mbedtls.c: ARM mbedTLS backend
*
* Copyright (C) 2007-2008 ircd-ratbox development team
* Copyright (C) 2007-2008 Aaron Sethman <androsyn@ratbox.org>
* Copyright (C) 2015 William Pitcock <nenolod@dereferenced.org>
* Copyright (C) 2016 Aaron Jones <aaronmdjones@gmail.com>
*
* 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.
*
* 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; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
* USA
*
* $Id$
*/
#include <libratbox_config.h>
#include <ratbox_lib.h>
#include <commio-int.h>
#include <commio-ssl.h>
#ifdef HAVE_MBEDTLS
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/certs.h"
#include "mbedtls/x509.h"
#include "mbedtls/ssl.h"
#include "mbedtls/net.h"
#include "mbedtls/error.h"
#include "mbedtls/debug.h"
#include "mbedtls/dhm.h"
#include "mbedtls/version.h"
#include "mbedtls_embedded_data.h"
typedef struct
{
mbedtls_x509_crt crt;
mbedtls_pk_context key;
mbedtls_dhm_context dhp;
mbedtls_ssl_config server_cfg;
mbedtls_ssl_config client_cfg;
size_t refcount;
} rb_mbedtls_cfg_context;
typedef struct
{
rb_mbedtls_cfg_context *cfg;
mbedtls_ssl_context ssl;
} rb_mbedtls_ssl_context;
#define SSL_C(x) ((rb_mbedtls_ssl_context *) (x)->ssl)->cfg
#define SSL_P(x) &((rb_mbedtls_ssl_context *) (x)->ssl)->ssl
static mbedtls_ctr_drbg_context ctr_drbg_ctx;
static mbedtls_entropy_context entropy_ctx;
static mbedtls_x509_crt dummy_ca_ctx;
static rb_mbedtls_cfg_context *rb_mbedtls_cfg = NULL;
struct ssl_connect
{
CNCB *callback;
void *data;
int timeout;
};
static void rb_ssl_connect_realcb(rb_fde_t *, int, struct ssl_connect *);
static int rb_sock_net_recv(void *, unsigned char *, size_t);
static int rb_sock_net_xmit(void *, const unsigned char *, size_t);
/*
* Internal MbedTLS-specific code
*/
static const char *
rb_get_ssl_strerror_internal(int err)
{
static char errbuf[512];
#ifdef MBEDTLS_ERROR_C
char mbed_errbuf[512];
mbedtls_strerror(err, mbed_errbuf, sizeof mbed_errbuf);
rb_snprintf(errbuf, sizeof errbuf, "(-0x%x) %s", -err, mbed_errbuf);
#else
rb_snprintf(errbuf, sizeof errbuf, "-0x%x", -err);
#endif
return errbuf;
}
static void
rb_mbedtls_cfg_incref(rb_mbedtls_cfg_context *cfg)
{
lrb_assert(cfg->refcount > 0);
cfg->refcount++;
}
static void
rb_mbedtls_cfg_decref(rb_mbedtls_cfg_context *cfg)
{
if(cfg == NULL)
return;
lrb_assert(cfg->refcount > 0);
if((--cfg->refcount) > 0)
return;
mbedtls_ssl_config_free(&cfg->client_cfg);
mbedtls_ssl_config_free(&cfg->server_cfg);
mbedtls_dhm_free(&cfg->dhp);
mbedtls_pk_free(&cfg->key);
mbedtls_x509_crt_free(&cfg->crt);
rb_free(cfg);
}
static rb_mbedtls_cfg_context *
rb_mbedtls_cfg_new(void)
{
rb_mbedtls_cfg_context *cfg;
int ret;
if((cfg = rb_malloc(sizeof(rb_mbedtls_cfg_context))) == NULL)
return NULL;
mbedtls_x509_crt_init(&cfg->crt);
mbedtls_pk_init(&cfg->key);
mbedtls_dhm_init(&cfg->dhp);
mbedtls_ssl_config_init(&cfg->server_cfg);
mbedtls_ssl_config_init(&cfg->client_cfg);
cfg->refcount = 1;
if((ret = mbedtls_ssl_config_defaults(&cfg->server_cfg,
MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_STREAM,
MBEDTLS_SSL_PRESET_DEFAULT)) != 0)
{
rb_lib_log("rb_mbedtls_cfg_new: ssl_config_defaults (server): %s",
rb_get_ssl_strerror_internal(ret));
rb_mbedtls_cfg_decref(cfg);
return NULL;
}
if((ret = mbedtls_ssl_config_defaults(&cfg->client_cfg,
MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM,
MBEDTLS_SSL_PRESET_DEFAULT)) != 0)
{
rb_lib_log("rb_mbedtls_cfg_new: ssl_config_defaults (client): %s",
rb_get_ssl_strerror_internal(ret));
rb_mbedtls_cfg_decref(cfg);
return NULL;
}
mbedtls_ssl_conf_rng(&cfg->server_cfg, mbedtls_ctr_drbg_random, &ctr_drbg_ctx);
mbedtls_ssl_conf_rng(&cfg->client_cfg, mbedtls_ctr_drbg_random, &ctr_drbg_ctx);
mbedtls_ssl_conf_ca_chain(&cfg->server_cfg, &dummy_ca_ctx, NULL);
mbedtls_ssl_conf_ca_chain(&cfg->client_cfg, &dummy_ca_ctx, NULL);
mbedtls_ssl_conf_authmode(&cfg->server_cfg, MBEDTLS_SSL_VERIFY_OPTIONAL);
mbedtls_ssl_conf_authmode(&cfg->client_cfg, MBEDTLS_SSL_VERIFY_NONE);
return cfg;
}
static void
rb_ssl_setup_mbed_context(rb_fde_t *F, mbedtls_ssl_config *const mbed_config)
{
rb_mbedtls_ssl_context *const mbed_ssl_ctx = rb_malloc(sizeof *mbed_ssl_ctx);
if(mbed_ssl_ctx == NULL)
{
rb_lib_log("rb_ssl_setup_mbed_context: rb_malloc: allocation failure");
rb_close(F);
return;
}
mbedtls_ssl_init(&mbed_ssl_ctx->ssl);
mbedtls_ssl_set_bio(&mbed_ssl_ctx->ssl, F, rb_sock_net_xmit, rb_sock_net_recv, NULL);
int ret;
if((ret = mbedtls_ssl_setup(&mbed_ssl_ctx->ssl, mbed_config)) != 0)
{
rb_lib_log("rb_ssl_setup_mbed_context: ssl_setup: %s",
rb_get_ssl_strerror_internal(ret));
mbedtls_ssl_free(&mbed_ssl_ctx->ssl);
rb_free(mbed_ssl_ctx);
rb_close(F);
return;
}
rb_mbedtls_cfg_incref(rb_mbedtls_cfg);
mbed_ssl_ctx->cfg = rb_mbedtls_cfg;
F->ssl = mbed_ssl_ctx;
}
static void
rb_ssl_accept_common(rb_fde_t *const F, void *const data)
{
lrb_assert(F != NULL);
lrb_assert(F->accept != NULL);
lrb_assert(F->accept->callback != NULL);
lrb_assert(F->ssl != NULL);
mbedtls_ssl_context *const ssl_ctx = (mbedtls_ssl_context *) SSL_P(F);
if(ssl_ctx->state != MBEDTLS_SSL_HANDSHAKE_OVER)
{
int ret = mbedtls_ssl_handshake(ssl_ctx);
switch(ret)
{
case 0:
F->handshake_count++;
break;
case MBEDTLS_ERR_SSL_WANT_READ:
rb_setselect(F, RB_SELECT_READ, rb_ssl_accept_common, NULL);
return;
case MBEDTLS_ERR_SSL_WANT_WRITE:
rb_setselect(F, RB_SELECT_WRITE, rb_ssl_accept_common, NULL);
return;
default:
F->ssl_errno = ret;
F->accept->callback(F, RB_ERROR_SSL, NULL, 0, F->accept->data);
return;
}
}
rb_settimeout(F, 0, NULL, NULL);
rb_setselect(F, RB_SELECT_READ | RB_SELECT_WRITE, NULL, NULL);
struct acceptdata *const ad = F->accept;
F->accept = NULL;
ad->callback(F, RB_OK, (struct sockaddr *)&ad->S, ad->addrlen, ad->data);
rb_free(ad);
}
static void
rb_ssl_tryconn_cb(rb_fde_t *const F, void *const data)
{
lrb_assert(F != NULL);
lrb_assert(F->ssl != NULL);
mbedtls_ssl_context *const ssl_ctx = SSL_P(F);
if(ssl_ctx->state != MBEDTLS_SSL_HANDSHAKE_OVER)
{
int ret = mbedtls_ssl_handshake(ssl_ctx);
switch(ret)
{
case 0:
F->handshake_count++;
break;
case MBEDTLS_ERR_SSL_WANT_READ:
rb_setselect(F, RB_SELECT_READ, rb_ssl_tryconn_cb, data);
return;
case MBEDTLS_ERR_SSL_WANT_WRITE:
rb_setselect(F, RB_SELECT_WRITE, rb_ssl_tryconn_cb, data);
return;
default:
errno = EIO;
F->ssl_errno = ret;
rb_ssl_connect_realcb(F, RB_ERROR_SSL, data);
return;
}
}
rb_ssl_connect_realcb(F, RB_OK, data);
}
/*
* External MbedTLS-specific code
*/
void
rb_ssl_shutdown(rb_fde_t *const F)
{
if(F == NULL || F->ssl == NULL)
return;
if(SSL_P(F) != NULL)
{
for(int i = 0; i < 4; i++)
{
int ret = mbedtls_ssl_close_notify(SSL_P(F));
if(ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
break;
}
mbedtls_ssl_free(SSL_P(F));
}
if(SSL_C(F) != NULL)
rb_mbedtls_cfg_decref(SSL_C(F));
rb_free(F->ssl);
}
int
rb_init_ssl(void)
{
int ret;
mbedtls_ctr_drbg_init(&ctr_drbg_ctx);
mbedtls_entropy_init(&entropy_ctx);
if((ret = mbedtls_ctr_drbg_seed(&ctr_drbg_ctx, mbedtls_entropy_func, &entropy_ctx,
(const unsigned char *)rb_mbedtls_personal_str, sizeof(rb_mbedtls_personal_str))) != 0)
{
rb_lib_log("rb_init_ssl: ctr_drbg_seed: %s",
rb_get_ssl_strerror_internal(ret));
return 0;
}
if((ret = mbedtls_x509_crt_parse_der(&dummy_ca_ctx, rb_mbedtls_dummy_ca_certificate,
sizeof(rb_mbedtls_dummy_ca_certificate))) != 0)
{
rb_lib_log("rb_init_ssl: x509_crt_parse_der (Dummy CA): %s",
rb_get_ssl_strerror_internal(ret));
return 0;
}
rb_lib_log("rb_init_ssl: MbedTLS backend initialised");
return 1;
}
int
rb_setup_ssl_server(const char *const certfile, const char *keyfile,
const char *const dhfile, const char *const cipherlist)
{
rb_mbedtls_cfg_context *newcfg;
int ret;
if(certfile == NULL)
{
rb_lib_log("rb_setup_ssl_server: no certificate file specified");
return 0;
}
if(keyfile == NULL)
keyfile = certfile;
if((newcfg = rb_mbedtls_cfg_new()) == NULL)
{
rb_lib_log("rb_setup_ssl_server: rb_mbedtls_cfg_new: allocation failed");
return 0;
}
if((ret = mbedtls_x509_crt_parse_file(&newcfg->crt, certfile)) != 0)
{
rb_lib_log("rb_setup_ssl_server: x509_crt_parse_file ('%s'): %s",
certfile, rb_get_ssl_strerror_internal(ret));
rb_mbedtls_cfg_decref(newcfg);
return 0;
}
if((ret = mbedtls_pk_parse_keyfile(&newcfg->key, keyfile, NULL)) != 0)
{
rb_lib_log("rb_setup_ssl_server: pk_parse_keyfile ('%s'): %s",
keyfile, rb_get_ssl_strerror_internal(ret));
rb_mbedtls_cfg_decref(newcfg);
return 0;
}
/* Absense of DH parameters does not matter with mbedTLS, as it comes with its own defaults
Thus, clients can still use DHE- ciphersuites, just over a weaker, common DH group
So, we do not consider failure to parse DH parameters as fatal */
if(dhfile == NULL)
{
rb_lib_log("rb_setup_ssl_server: no DH parameters file specified");
}
else
{
if((ret = mbedtls_dhm_parse_dhmfile(&newcfg->dhp, dhfile)) != 0)
{
rb_lib_log("rb_setup_ssl_server: dhm_parse_dhmfile ('%s'): %s",
dhfile, rb_get_ssl_strerror_internal(ret));
}
else if((ret = mbedtls_ssl_conf_dh_param_ctx(&newcfg->server_cfg, &newcfg->dhp)) != 0)
{
rb_lib_log("rb_setup_ssl_server: ssl_conf_dh_param_ctx: %s",
rb_get_ssl_strerror_internal(ret));
}
}
if((ret = mbedtls_ssl_conf_own_cert(&newcfg->server_cfg, &newcfg->crt, &newcfg->key)) != 0)
{
rb_lib_log("rb_setup_ssl_server: ssl_conf_own_cert (server): %s",
rb_get_ssl_strerror_internal(ret));
rb_mbedtls_cfg_decref(newcfg);
return 0;
}
if((ret = mbedtls_ssl_conf_own_cert(&newcfg->client_cfg, &newcfg->crt, &newcfg->key)) != 0)
{
rb_lib_log("rb_setup_ssl_server: ssl_conf_own_cert (client): %s",
rb_get_ssl_strerror_internal(ret));
rb_mbedtls_cfg_decref(newcfg);
return 0;
}
/* XXX support cipher lists when added to mbedtls */
rb_mbedtls_cfg_decref(rb_mbedtls_cfg);
rb_mbedtls_cfg = newcfg;
rb_lib_log("rb_setup_ssl_server: TLS configuration successful");
return 1;
}
int
rb_init_prng(const char *const path, prng_seed_t seed_type)
{
rb_lib_log("rb_init_prng: Skipping PRNG initialisation; not required by MbedTLS backend");
return 1;
}
int
rb_get_random(void *const buf, size_t length)
{
int ret;
if((ret = mbedtls_ctr_drbg_random(&ctr_drbg_ctx, buf, length)) != 0)
{
rb_lib_log("rb_get_random: ctr_drbg_random: %s",
rb_get_ssl_strerror_internal(ret));
return 0;
}
return 1;
}
const char *
rb_get_ssl_strerror(rb_fde_t *const F)
{
return rb_get_ssl_strerror_internal(F->ssl_errno);
}
int
rb_get_ssl_certfp(rb_fde_t *const F, uint8_t certfp[RB_SSL_CERTFP_LEN], int method)
{
const mbedtls_x509_crt *peer_cert;
const mbedtls_md_info_t *md_info;
mbedtls_md_type_t md_type;
int hashlen;
int ret;
switch(method)
{
case RB_SSL_CERTFP_METH_SHA1:
md_type = MBEDTLS_MD_SHA1;
hashlen = RB_SSL_CERTFP_LEN_SHA1;
break;
case RB_SSL_CERTFP_METH_SHA256:
md_type = MBEDTLS_MD_SHA256;
hashlen = RB_SSL_CERTFP_LEN_SHA256;
break;
case RB_SSL_CERTFP_METH_SHA512:
md_type = MBEDTLS_MD_SHA512;
hashlen = RB_SSL_CERTFP_LEN_SHA512;
break;
default:
return 0;
}
if((peer_cert = mbedtls_ssl_get_peer_cert(SSL_P(F))) == NULL)
return 0;
if((md_info = mbedtls_md_info_from_type(md_type)) == NULL)
return 0;
if((ret = mbedtls_md(md_info, peer_cert->raw.p, peer_cert->raw.len, certfp)) != 0)
{
rb_lib_log("rb_get_ssl_certfp: mbedtls_md: %s",
rb_get_ssl_strerror_internal(ret));
return 0;
}
return hashlen;
}
void
rb_get_ssl_info(char *const buf, size_t len)
{
char version_str[512];
mbedtls_version_get_string(version_str);
(void) rb_snprintf(buf, len, "ARM mbedTLS: compiled (v%s), library (v%s)",
MBEDTLS_VERSION_STRING, version_str);
}
const char *
rb_ssl_get_cipher(rb_fde_t *const F)
{
if(F == NULL || F->ssl == NULL || SSL_P(F) == NULL)
return NULL;
static char buf[512];
const char *const version = mbedtls_ssl_get_version(SSL_P(F));
const char *const cipher = mbedtls_ssl_get_ciphersuite(SSL_P(F));
(void) rb_snprintf(buf, sizeof buf, "%s, %s", version, cipher);
return buf;
}
ssize_t
rb_ssl_read(rb_fde_t *const F, void *const buf, size_t count)
{
lrb_assert(F != NULL);
lrb_assert(F->ssl != NULL);
ssize_t ret = (ssize_t) mbedtls_ssl_read(SSL_P(F), buf, count);
if(ret > 0)
return ret;
switch(ret)
{
case MBEDTLS_ERR_SSL_WANT_READ:
errno = EAGAIN;
return RB_RW_SSL_NEED_READ;
case MBEDTLS_ERR_SSL_WANT_WRITE:
errno = EAGAIN;
return RB_RW_SSL_NEED_WRITE;
default:
errno = EIO;
F->ssl_errno = ret;
return RB_RW_SSL_ERROR;
}
}
ssize_t
rb_ssl_write(rb_fde_t *const F, const void *const buf, size_t count)
{
lrb_assert(F != NULL);
lrb_assert(F->ssl != NULL);
ssize_t ret = (ssize_t) mbedtls_ssl_write(SSL_P(F), buf, count);
if(ret > 0)
return ret;
switch(ret)
{
case MBEDTLS_ERR_SSL_WANT_READ:
errno = EAGAIN;
return RB_RW_SSL_NEED_READ;
case MBEDTLS_ERR_SSL_WANT_WRITE:
errno = EAGAIN;
return RB_RW_SSL_NEED_WRITE;
default:
errno = EIO;
F->ssl_errno = ret;
return RB_RW_SSL_ERROR;
}
}
/*
* Internal library-agnostic code
* Mostly copied from the OpenSSL backend, with some optimisations and complete const-correctness
*/
static void
rb_ssl_connect_realcb(rb_fde_t *const F, int status, struct ssl_connect *const sconn)
{
lrb_assert(F->connect != NULL);
F->connect->callback = sconn->callback;
F->connect->data = sconn->data;
rb_connect_callback(F, status);
rb_free(sconn);
}
static void
rb_ssl_timeout_cb(rb_fde_t *const F, void *const data)
{
lrb_assert(F->accept != NULL);
lrb_assert(F->accept->callback != NULL);
F->accept->callback(F, RB_ERR_TIMEOUT, NULL, 0, F->accept->data);
}
static void
rb_ssl_tryconn_timeout_cb(rb_fde_t *const F, void *const data)
{
rb_ssl_connect_realcb(F, RB_ERR_TIMEOUT, data);
}
static void
rb_ssl_tryconn(rb_fde_t *const F, int status, void *const data)
{
lrb_assert(F != NULL);
if(status != RB_OK)
{
rb_ssl_connect_realcb(F, status, data);
return;
}
F->type |= RB_FD_SSL;
struct ssl_connect *const sconn = data;
rb_settimeout(F, sconn->timeout, rb_ssl_tryconn_timeout_cb, sconn);
rb_ssl_setup_mbed_context(F, &rb_mbedtls_cfg->client_cfg);
rb_ssl_tryconn_cb(F, sconn);
}
static int
rb_sock_net_recv(void *const context_ptr, unsigned char *const buf, size_t count)
{
rb_fde_t *const F = (rb_fde_t *)context_ptr;
int ret = (int) read(F->fd, buf, count);
if(ret < 0 && rb_ignore_errno(errno))
return MBEDTLS_ERR_SSL_WANT_READ;
return ret;
}
static int
rb_sock_net_xmit(void *const context_ptr, const unsigned char *const buf, size_t count)
{
rb_fde_t *const F = (rb_fde_t *)context_ptr;
int ret = (int) write(F->fd, buf, count);
if(ret < 0 && rb_ignore_errno(errno))
return MBEDTLS_ERR_SSL_WANT_READ;
return ret;
}
/*
* External library-agnostic code
* Mostly copied from the OpenSSL backend, with some optimisations and const-correctness
*/
int
rb_supports_ssl(void)
{
return 1;
}
unsigned int
rb_ssl_handshake_count(rb_fde_t *const F)
{
return F->handshake_count;
}
void
rb_ssl_clear_handshake_count(rb_fde_t *const F)
{
F->handshake_count = 0;
}
void
rb_ssl_start_accepted(rb_fde_t *const F, ACCB *const cb, void *const data, int timeout)
{
F->type |= RB_FD_SSL;
F->accept = rb_malloc(sizeof(struct acceptdata));
F->accept->callback = cb;
F->accept->data = data;
rb_settimeout(F, timeout, rb_ssl_timeout_cb, NULL);
F->accept->addrlen = 0;
(void) memset(&F->accept->S, 0x00, sizeof F->accept->S);
rb_ssl_setup_mbed_context(F, &rb_mbedtls_cfg->server_cfg);
rb_ssl_accept_common(F, NULL);
}
void
rb_ssl_accept_setup(rb_fde_t *const srv_F, rb_fde_t *const cli_F, struct sockaddr *const st, int addrlen)
{
cli_F->type |= RB_FD_SSL;
cli_F->accept = rb_malloc(sizeof(struct acceptdata));
cli_F->accept->callback = srv_F->accept->callback;
cli_F->accept->data = srv_F->accept->data;
rb_settimeout(cli_F, 10, rb_ssl_timeout_cb, NULL);
cli_F->accept->addrlen = addrlen;
(void) memset(&cli_F->accept->S, 0x00, sizeof cli_F->accept->S);
(void) memcpy(&cli_F->accept->S, st, addrlen);
rb_ssl_setup_mbed_context(cli_F, &rb_mbedtls_cfg->server_cfg);
rb_ssl_accept_common(cli_F, NULL);
}
int
rb_ssl_listen(rb_fde_t *const F, int backlog, int defer_accept)
{
int result = rb_listen(F, backlog, defer_accept);
F->type = RB_FD_SOCKET | RB_FD_LISTEN | RB_FD_SSL;
return result;
}
void
rb_connect_tcp_ssl(rb_fde_t *const F, struct sockaddr *const dest, struct sockaddr *const clocal, int socklen,
CNCB *const callback, void *const data, int timeout)
{
if(F == NULL)
return;
struct ssl_connect *const sconn = rb_malloc(sizeof(struct ssl_connect));
sconn->data = data;
sconn->callback = callback;
sconn->timeout = timeout;
rb_connect_tcp(F, dest, clocal, socklen, rb_ssl_tryconn, sconn, timeout);
}
void
rb_ssl_start_connected(rb_fde_t *const F, CNCB *const callback, void *const data, int timeout)
{
if(F == NULL)
return;
F->connect = rb_malloc(sizeof(struct conndata));
F->connect->callback = callback;
F->connect->data = data;
F->type |= RB_FD_SSL;
struct ssl_connect *const sconn = rb_malloc(sizeof(struct ssl_connect));
sconn->data = data;
sconn->callback = callback;
sconn->timeout = timeout;
rb_settimeout(F, sconn->timeout, rb_ssl_tryconn_timeout_cb, sconn);
rb_ssl_setup_mbed_context(F, &rb_mbedtls_cfg->client_cfg);
rb_ssl_tryconn_cb(F, sconn);
}
#endif /* HAVE_MBEDTLS */