blob: e54b292a882154615e69db7bafb55c44fba546ae [file] [log] [blame]
/**
* \file session_client_tls.c
* \author Radek Krejci <rkrejci@cesnet.cz>
* \author Michal Vasko <mvasko@cesnet.cz>
* \brief libnetconf2 - TLS specific session client transport functions
*
* This source is compiled only with libssl.
*
* Copyright (c) 2015 CESNET, z.s.p.o.
*
* This source code is licensed under BSD 3-Clause License (the "License").
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://opensource.org/licenses/BSD-3-Clause
*/
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <libyang/libyang.h>
#include <openssl/err.h>
#include <openssl/x509.h>
#include "session_client.h"
#include "session_client_ch.h"
#include "libnetconf.h"
extern struct nc_client_opts client_opts;
static struct nc_client_tls_opts tls_opts;
static struct nc_client_tls_opts tls_ch_opts;
static int tlsauth_ch;
static int
tlsauth_verify_callback(int preverify_ok, X509_STORE_CTX *x509_ctx)
{
X509_STORE_CTX store_ctx;
X509_OBJECT obj;
X509_NAME *subject, *issuer;
X509 *cert;
X509_CRL *crl;
X509_REVOKED *revoked;
EVP_PKEY *pubkey;
int i, n, rc;
ASN1_TIME *next_update = NULL;
struct nc_client_tls_opts *opts;
if (!preverify_ok) {
return 0;
}
opts = (tlsauth_ch ? &tls_ch_opts : &tls_opts);
if (!opts->crl_store) {
/* nothing to check */
return 1;
}
cert = X509_STORE_CTX_get_current_cert(x509_ctx);
subject = X509_get_subject_name(cert);
issuer = X509_get_issuer_name(cert);
/* try to retrieve a CRL corresponding to the _subject_ of
* the current certificate in order to verify it's integrity */
memset((char *)&obj, 0, sizeof obj);
X509_STORE_CTX_init(&store_ctx, opts->crl_store, NULL, NULL);
rc = X509_STORE_get_by_subject(&store_ctx, X509_LU_CRL, subject, &obj);
X509_STORE_CTX_cleanup(&store_ctx);
crl = obj.data.crl;
if (rc > 0 && crl) {
next_update = X509_CRL_get_nextUpdate(crl);
/* verify the signature on this CRL */
pubkey = X509_get_pubkey(cert);
if (X509_CRL_verify(crl, pubkey) <= 0) {
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CRL_SIGNATURE_FAILURE);
X509_OBJECT_free_contents(&obj);
if (pubkey) {
EVP_PKEY_free(pubkey);
}
return 0; /* fail */
}
if (pubkey) {
EVP_PKEY_free(pubkey);
}
/* check date of CRL to make sure it's not expired */
if (!next_update) {
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD);
X509_OBJECT_free_contents(&obj);
return 0; /* fail */
}
if (X509_cmp_current_time(next_update) < 0) {
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CRL_HAS_EXPIRED);
X509_OBJECT_free_contents(&obj);
return 0; /* fail */
}
X509_OBJECT_free_contents(&obj);
}
/* try to retrieve a CRL corresponding to the _issuer_ of
* the current certificate in order to check for revocation */
memset((char *)&obj, 0, sizeof obj);
X509_STORE_CTX_init(&store_ctx, opts->crl_store, NULL, NULL);
rc = X509_STORE_get_by_subject(&store_ctx, X509_LU_CRL, issuer, &obj);
X509_STORE_CTX_cleanup(&store_ctx);
crl = obj.data.crl;
if (rc > 0 && crl) {
/* check if the current certificate is revoked by this CRL */
n = sk_X509_REVOKED_num(X509_CRL_get_REVOKED(crl));
for (i = 0; i < n; i++) {
revoked = sk_X509_REVOKED_value(X509_CRL_get_REVOKED(crl), i);
if (ASN1_INTEGER_cmp(revoked->serialNumber, X509_get_serialNumber(cert)) == 0) {
ERR("Certificate revoked!");
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CERT_REVOKED);
X509_OBJECT_free_contents(&obj);
return 0; /* fail */
}
}
X509_OBJECT_free_contents(&obj);
}
return 1; /* success */
}
static void
_nc_client_tls_destroy_opts(struct nc_client_tls_opts *opts)
{
free(opts->cert_path);
free(opts->key_path);
free(opts->ca_file);
free(opts->ca_dir);
SSL_CTX_free(opts->tls_ctx);
free(opts->crl_file);
free(opts->crl_dir);
X509_STORE_free(opts->crl_store);
}
void
nc_client_tls_destroy_opts(void)
{
_nc_client_tls_destroy_opts(&tls_opts);
_nc_client_tls_destroy_opts(&tls_ch_opts);
}
static int
_nc_client_tls_set_cert_key_paths(const char *client_cert, const char *client_key, struct nc_client_tls_opts *opts)
{
if (!client_cert) {
ERRARG("client_cert");
return -1;
}
free(opts->cert_path);
free(opts->key_path);
opts->cert_path = strdup(client_cert);
if (!opts->cert_path) {
ERRMEM;
return -1;
}
if (client_key) {
opts->key_path = strdup(client_key);
if (!opts->key_path) {
ERRMEM;
return -1;
}
} else {
opts->key_path = NULL;
}
opts->tls_ctx_change = 1;
return 0;
}
API int
nc_client_tls_set_cert_key_paths(const char *client_cert, const char *client_key)
{
return _nc_client_tls_set_cert_key_paths(client_cert, client_key, &tls_opts);
}
API int
nc_client_tls_ch_set_cert_key_paths(const char *client_cert, const char *client_key)
{
return _nc_client_tls_set_cert_key_paths(client_cert, client_key, &tls_ch_opts);
}
static void
_nc_client_tls_get_cert_key_paths(const char **client_cert, const char **client_key, struct nc_client_tls_opts *opts)
{
if (!client_cert && !client_key) {
ERRARG("client_cert and client_key");
return;
}
if (client_cert) {
*client_cert = opts->cert_path;
}
if (client_key) {
*client_key = opts->key_path;
}
}
API void
nc_client_tls_get_cert_key_paths(const char **client_cert, const char **client_key)
{
_nc_client_tls_get_cert_key_paths(client_cert, client_key, &tls_opts);
}
API void
nc_client_tls_ch_get_cert_key_paths(const char **client_cert, const char **client_key)
{
_nc_client_tls_get_cert_key_paths(client_cert, client_key, &tls_ch_opts);
}
static int
_nc_client_tls_set_trusted_ca_paths(const char *ca_file, const char *ca_dir, struct nc_client_tls_opts *opts)
{
if (!ca_file && !ca_dir) {
ERRARG("ca_file and ca_dir");
return -1;
}
free(opts->ca_file);
free(opts->ca_dir);
if (ca_file) {
opts->ca_file = strdup(ca_file);
if (!opts->ca_file) {
ERRMEM;
return -1;
}
} else {
opts->ca_file = NULL;
}
if (ca_dir) {
opts->ca_dir = strdup(ca_dir);
if (!opts->ca_dir) {
ERRMEM;
return -1;
}
} else {
opts->ca_dir = NULL;
}
opts->tls_ctx_change = 1;
return 0;
}
API int
nc_client_tls_set_trusted_ca_paths(const char *ca_file, const char *ca_dir)
{
return _nc_client_tls_set_trusted_ca_paths(ca_file, ca_dir, &tls_opts);
}
API int
nc_client_tls_ch_set_trusted_ca_paths(const char *ca_file, const char *ca_dir)
{
return _nc_client_tls_set_trusted_ca_paths(ca_file, ca_dir, &tls_ch_opts);
}
static void
_nc_client_tls_get_trusted_ca_paths(const char **ca_file, const char **ca_dir, struct nc_client_tls_opts *opts)
{
if (!ca_file && !ca_dir) {
ERRARG("ca_file and ca_dir");
return;
}
if (ca_file) {
*ca_file = opts->ca_file;
}
if (ca_dir) {
*ca_dir = opts->ca_dir;
}
}
API void
nc_client_tls_get_trusted_ca_paths(const char **ca_file, const char **ca_dir)
{
_nc_client_tls_get_trusted_ca_paths(ca_file, ca_dir, &tls_opts);
}
API void
nc_client_tls_ch_get_trusted_ca_paths(const char **ca_file, const char **ca_dir)
{
_nc_client_tls_get_trusted_ca_paths(ca_file, ca_dir, &tls_ch_opts);
}
static int
_nc_client_tls_set_crl_paths(const char *crl_file, const char *crl_dir, struct nc_client_tls_opts *opts)
{
if (!crl_file && !crl_dir) {
ERRARG("crl_file and crl_dir");
return -1;
}
free(opts->crl_file);
free(opts->crl_dir);
if (crl_file) {
opts->crl_file = strdup(crl_file);
if (!opts->crl_file) {
ERRMEM;
return -1;
}
} else {
opts->crl_file = NULL;
}
if (crl_dir) {
opts->crl_dir = strdup(crl_dir);
if (!opts->crl_dir) {
ERRMEM;
return -1;
}
} else {
opts->crl_dir = NULL;
}
opts->crl_store_change = 1;
return 0;
}
API int
nc_client_tls_set_crl_paths(const char *crl_file, const char *crl_dir)
{
return _nc_client_tls_set_crl_paths(crl_file, crl_dir, &tls_opts);
}
API int
nc_client_tls_ch_set_crl_paths(const char *crl_file, const char *crl_dir)
{
return _nc_client_tls_set_crl_paths(crl_file, crl_dir, &tls_ch_opts);
}
static void
_nc_client_tls_get_crl_paths(const char **crl_file, const char **crl_dir, struct nc_client_tls_opts *opts)
{
if (!crl_file && !crl_dir) {
ERRARG("crl_file and crl_dir");
return;
}
if (crl_file) {
*crl_file = opts->crl_file;
}
if (crl_dir) {
*crl_dir = opts->crl_dir;
}
}
API void
nc_client_tls_get_crl_paths(const char **crl_file, const char **crl_dir)
{
_nc_client_tls_get_crl_paths(crl_file, crl_dir, &tls_opts);
}
API void
nc_client_tls_ch_get_crl_paths(const char **crl_file, const char **crl_dir)
{
_nc_client_tls_get_crl_paths(crl_file, crl_dir, &tls_ch_opts);
}
API int
nc_client_tls_ch_add_bind_listen(const char *address, uint16_t port)
{
return nc_client_ch_add_bind_listen(address, port, NC_TI_OPENSSL);
}
API int
nc_client_tls_ch_del_bind(const char *address, uint16_t port)
{
return nc_client_ch_del_bind(address, port, NC_TI_OPENSSL);
}
static int
nc_client_tls_update_opts(struct nc_client_tls_opts *opts)
{
char *key;
X509_LOOKUP *lookup;
if (!opts->tls_ctx || opts->tls_ctx_change) {
SSL_CTX_free(opts->tls_ctx);
/* prepare global SSL context, allow only mandatory TLS 1.2 */
if (!(opts->tls_ctx = SSL_CTX_new(TLSv1_2_client_method()))) {
ERR("Unable to create OpenSSL context (%s).", ERR_reason_error_string(ERR_get_error()));
return -1;
}
SSL_CTX_set_verify(opts->tls_ctx, SSL_VERIFY_PEER, tlsauth_verify_callback);
/* get peer certificate */
if (SSL_CTX_use_certificate_file(opts->tls_ctx, opts->cert_path, SSL_FILETYPE_PEM) != 1) {
ERR("Loading the client certificate from \'%s\' failed (%s).", opts->cert_path, ERR_reason_error_string(ERR_get_error()));
return -1;
}
/* if the file with private key not specified, expect that the private key is stored with the certificate */
if (!opts->key_path) {
key = opts->cert_path;
} else {
key = opts->key_path;
}
if (SSL_CTX_use_PrivateKey_file(opts->tls_ctx, key, SSL_FILETYPE_PEM) != 1) {
ERR("Loading the client priavte key from \'%s\' failed (%s).", key, ERR_reason_error_string(ERR_get_error()));
return -1;
}
if (!SSL_CTX_load_verify_locations(opts->tls_ctx, opts->ca_file, opts->ca_dir)) {
ERR("Failed to load the locations of trusted CA certificates (%s).", ERR_reason_error_string(ERR_get_error()));
return -1;
}
}
if (opts->crl_store_change || (!opts->crl_store && (opts->crl_file || opts->crl_dir))) {
/* set the revocation store with the correct paths for the callback */
X509_STORE_free(opts->crl_store);
opts->crl_store = X509_STORE_new();
if (!opts->crl_store) {
ERR("Unable to create a certificate store (%s).", ERR_reason_error_string(ERR_get_error()));
return -1;
}
opts->crl_store->cache = 0;
if (opts->crl_file) {
if (!(lookup = X509_STORE_add_lookup(opts->crl_store, X509_LOOKUP_file()))) {
ERR("Failed to add lookup method to CRL checking.");
return -1;
}
if (X509_LOOKUP_add_dir(lookup, opts->crl_file, X509_FILETYPE_PEM) != 1) {
ERR("Failed to add the revocation lookup file \"%s\".", opts->crl_file);
return -1;
}
}
if (opts->crl_dir) {
if (!(lookup = X509_STORE_add_lookup(opts->crl_store, X509_LOOKUP_hash_dir()))) {
ERR("Failed to add lookup method to CRL checking.");
return -1;
}
if (X509_LOOKUP_add_dir(lookup, opts->crl_dir, X509_FILETYPE_PEM) != 1) {
ERR("Failed to add the revocation lookup directory \"%s\".", opts->crl_dir);
return -1;
}
}
}
return 0;
}
API struct nc_session *
nc_connect_tls(const char *host, unsigned short port, struct ly_ctx *ctx)
{
struct nc_session *session = NULL;
int sock, verify, ret;
uint32_t elapsed_usec = 0;
if (!tls_opts.cert_path || (!tls_opts.ca_file && !tls_opts.ca_dir)) {
ERRINIT;
return NULL;
}
/* process parameters */
if (!host || strisempty(host)) {
host = "localhost";
}
if (!port) {
port = NC_PORT_TLS;
}
/* create/update TLS structures */
if (nc_client_tls_update_opts(&tls_opts)) {
return NULL;
}
/* prepare session structure */
session = calloc(1, sizeof *session);
if (!session) {
ERRMEM;
return NULL;
}
session->status = NC_STATUS_STARTING;
session->side = NC_CLIENT;
/* transport lock */
session->ti_lock = malloc(sizeof *session->ti_lock);
if (!session->ti_lock) {
ERRMEM;
goto fail;
}
pthread_mutex_init(session->ti_lock, NULL);
/* fill the session */
session->ti_type = NC_TI_OPENSSL;
if (!(session->ti.tls = SSL_new(tls_opts.tls_ctx))) {
ERR("Failed to create a new TLS session structure (%s).", ERR_reason_error_string(ERR_get_error()));
goto fail;
}
/* create and assign socket */
sock = nc_sock_connect(host, port);
if (sock == -1) {
ERR("Unable to connect to %s:%u (%s).", host, port, strerror(errno));
goto fail;
}
SSL_set_fd(session->ti.tls, sock);
/* set the SSL_MODE_AUTO_RETRY flag to allow OpenSSL perform re-handshake automatically */
SSL_set_mode(session->ti.tls, SSL_MODE_AUTO_RETRY);
/* connect and perform the handshake */
tlsauth_ch = 0;
while (((ret = SSL_connect(session->ti.tls)) == -1) && (SSL_get_error(session->ti.tls, ret) == SSL_ERROR_WANT_READ)) {
usleep(NC_TIMEOUT_STEP);
elapsed_usec += NC_TIMEOUT_STEP;
if (elapsed_usec / 1000 >= NC_TRANSPORT_TIMEOUT) {
ERR("SSL_connect timeout.");
goto fail;
}
}
if (ret != 1) {
switch (SSL_get_error(session->ti.tls, ret)) {
case SSL_ERROR_SYSCALL:
ERR("SSL_connect failed (%s).", strerror(errno));
break;
case SSL_ERROR_SSL:
ERR("SSL_connect failed (%s).", ERR_reason_error_string(ERR_get_error()));
break;
default:
ERR("SSL_connect failed.");
break;
}
goto fail;
}
/* check certificate verification result */
verify = SSL_get_verify_result(session->ti.tls);
switch (verify) {
case X509_V_OK:
VRB("Server certificate successfully verified.");
break;
default:
WRN("Server certificate verification problem (%s).", X509_verify_cert_error_string(verify));
}
/* assign context (dicionary needed for handshake) */
if (!ctx) {
if (client_opts.schema_searchpath) {
ctx = ly_ctx_new(client_opts.schema_searchpath);
} else {
ctx = ly_ctx_new(SCHEMAS_DIR);
}
/* definitely should not happen, but be ready */
if (!ctx && !(ctx = ly_ctx_new(NULL))) {
/* that's just it */
goto fail;
}
} else {
session->flags |= NC_SESSION_SHAREDCTX;
}
session->ctx = ctx;
/* NETCONF handshake */
if (nc_handshake(session) != NC_MSG_HELLO) {
goto fail;
}
session->status = NC_STATUS_RUNNING;
if (nc_ctx_check_and_fill(session) == -1) {
goto fail;
}
/* store information into session and the dictionary */
session->host = lydict_insert(ctx, host, 0);
session->port = port;
session->username = lydict_insert(ctx, "certificate-based", 0);
return session;
fail:
nc_session_free(session, NULL);
return NULL;
}
API struct nc_session *
nc_connect_libssl(SSL *tls, struct ly_ctx *ctx)
{
struct nc_session *session;
if (!tls) {
ERRARG("tls");
return NULL;
} else if (!SSL_is_init_finished(tls)) {
ERR("Supplied TLS session is not fully connected!");
return NULL;
}
/* prepare session structure */
session = calloc(1, sizeof *session);
if (!session) {
ERRMEM;
return NULL;
}
session->status = NC_STATUS_STARTING;
session->side = NC_CLIENT;
/* transport lock */
session->ti_lock = malloc(sizeof *session->ti_lock);
if (!session->ti_lock) {
ERRMEM;
goto fail;
}
pthread_mutex_init(session->ti_lock, NULL);
session->ti_type = NC_TI_OPENSSL;
session->ti.tls = tls;
/* assign context (dicionary needed for handshake) */
if (!ctx) {
if (client_opts.schema_searchpath) {
ctx = ly_ctx_new(client_opts.schema_searchpath);
} else {
ctx = ly_ctx_new(SCHEMAS_DIR);
}
/* definitely should not happen, but be ready */
if (!ctx && !(ctx = ly_ctx_new(NULL))) {
/* that's just it */
goto fail;
}
} else {
session->flags |= NC_SESSION_SHAREDCTX;
}
session->ctx = ctx;
/* NETCONF handshake */
if (nc_handshake(session) != NC_MSG_HELLO) {
goto fail;
}
session->status = NC_STATUS_RUNNING;
if (nc_ctx_check_and_fill(session) == -1) {
goto fail;
}
return session;
fail:
nc_session_free(session, NULL);
return NULL;
}
struct nc_session *
nc_accept_callhome_tls_sock(int sock, const char *host, uint16_t port, struct ly_ctx *ctx, int timeout)
{
int verify, ret, elapsed_usec = 0;
SSL *tls;
struct nc_session *session;
if (nc_client_tls_update_opts(&tls_ch_opts)) {
close(sock);
return NULL;
}
if (!(tls = SSL_new(tls_ch_opts.tls_ctx))) {
ERR("Failed to create new TLS session structure (%s).", ERR_reason_error_string(ERR_get_error()));
close(sock);
return NULL;
}
SSL_set_fd(tls, sock);
/* set the SSL_MODE_AUTO_RETRY flag to allow OpenSSL perform re-handshake automatically */
SSL_set_mode(tls, SSL_MODE_AUTO_RETRY);
/* connect and perform the handshake */
tlsauth_ch = 1;
while (((ret = SSL_connect(tls)) == -1) && (SSL_get_error(tls, ret) == SSL_ERROR_WANT_READ)) {
usleep(NC_TIMEOUT_STEP);
elapsed_usec += NC_TIMEOUT_STEP;
if ((timeout > -1) && (elapsed_usec / 1000 >= timeout)) {
ERR("SSL_connect timeout.");
SSL_free(tls);
return NULL;
}
}
if (ret != 1) {
switch (SSL_get_error(tls, ret)) {
case SSL_ERROR_SYSCALL:
ERR("SSL_connect failed (%s).", strerror(errno));
break;
case SSL_ERROR_SSL:
ERR("SSL_connect failed (%s).", ERR_reason_error_string(ERR_get_error()));
break;
default:
ERR("SSL_connect failed.");
break;
}
SSL_free(tls);
return NULL;
}
/* check certificate verification result */
verify = SSL_get_verify_result(tls);
switch (verify) {
case X509_V_OK:
VRB("Server certificate successfully verified.");
break;
default:
WRN("Server certificate verification problem (%s).", X509_verify_cert_error_string(verify));
}
session = nc_connect_libssl(tls, ctx);
if (session) {
session->flags |= NC_SESSION_CALLHOME;
/* store information into session and the dictionary */
session->host = lydict_insert(session->ctx, host, 0);
session->port = port;
session->username = lydict_insert(session->ctx, "certificate-based", 0);
}
return session;
}