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  • /*
     * libwebsockets - mbedTLS-specific lws apis
     *
     * Copyright (C) 2010-2017 Andy Green <andy@warmcat.com>
     *
     *  This library is free software; you can redistribute it and/or
     *  modify it under the terms of the GNU Lesser General Public
     *  License as published by the Free Software Foundation:
     *  version 2.1 of the License.
     *
     *  This library 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
     *  Lesser General Public License for more details.
     *
     *  You should have received a copy of the GNU Lesser General Public
     *  License along with this library; if not, write to the Free Software
     *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
     *  MA  02110-1301  USA
     */
    
    
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    #include <mbedtls/oid.h>
    
    
    void
    lws_ssl_elaborate_error(void)
    {
    }
    
    int
    
    lws_context_init_ssl_library(const struct lws_context_creation_info *info)
    
    {
    	lwsl_info(" Compiled with MbedTLS support\n");
    
    	if (!lws_check_opt(info->options, LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT))
    
    		lwsl_info(" SSL disabled: no "
    			  "LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT\n");
    
    
    	return 0;
    }
    
    LWS_VISIBLE void
    lws_ssl_destroy(struct lws_vhost *vhost)
    {
    	if (!lws_check_opt(vhost->context->options,
    			   LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT))
    		return;
    
    
    	if (vhost->tls.ssl_ctx)
    		SSL_CTX_free(vhost->tls.ssl_ctx);
    	if (!vhost->tls.user_supplied_ssl_ctx && vhost->tls.ssl_client_ctx)
    		SSL_CTX_free(vhost->tls.ssl_client_ctx);
    
    	if (vhost->tls.x509_client_CA)
    		X509_free(vhost->tls.x509_client_CA);
    
    }
    
    LWS_VISIBLE int
    lws_ssl_capable_read(struct lws *wsi, unsigned char *buf, int len)
    {
    	struct lws_context *context = wsi->context;
    	struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
    	int n = 0, m;
    
    
    		return lws_ssl_capable_read_no_ssl(wsi, buf, len);
    
    	lws_stats_atomic_bump(context, pt, LWSSTATS_C_API_READ, 1);
    
    	errno = 0;
    
    	n = SSL_read(wsi->tls.ssl, buf, len);
    
    #if defined(LWS_WITH_ESP32)
    
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    	if (!n && errno == LWS_ENOTCONN) {
    
    		lwsl_debug("%p: SSL_read ENOTCONN\n", wsi);
    		return LWS_SSL_CAPABLE_ERROR;
    	}
    #endif
    #if defined(LWS_WITH_STATS)
    
    	if (!wsi->seen_rx && wsi->accept_start_us) {
    
                    lws_stats_atomic_bump(wsi->context, pt,
                    		      LWSSTATS_MS_SSL_RX_DELAY,
    
    				lws_time_in_microseconds() -
    				wsi->accept_start_us);
    
                    lws_stats_atomic_bump(wsi->context, pt,
                    		      LWSSTATS_C_SSL_CONNS_HAD_RX, 1);
    		wsi->seen_rx = 1;
    	}
    #endif
    
    
    	lwsl_debug("%p: SSL_read says %d\n", wsi, n);
    	/* manpage: returning 0 means connection shut down */
    	if (!n) {
    		wsi->socket_is_permanently_unusable = 1;
    
    		return LWS_SSL_CAPABLE_ERROR;
    	}
    
    	if (n < 0) {
    
    		m = SSL_get_error(wsi->tls.ssl, n);
    
    		lwsl_debug("%p: ssl err %d errno %d\n", wsi, m, errno);
    
    		if (errno == LWS_ENOTCONN) {
    			/* If the socket isn't connected anymore, bail out. */
    			wsi->socket_is_permanently_unusable = 1;
    			return LWS_SSL_CAPABLE_ERROR;
    		}
    
    		if (m == SSL_ERROR_ZERO_RETURN ||
    		    m == SSL_ERROR_SYSCALL)
    			return LWS_SSL_CAPABLE_ERROR;
    
    
    		if (m == SSL_ERROR_WANT_READ || SSL_want_read(wsi->tls.ssl)) {
    
    			lwsl_debug("%s: WANT_READ\n", __func__);
    			lwsl_debug("%p: LWS_SSL_CAPABLE_MORE_SERVICE\n", wsi);
    			return LWS_SSL_CAPABLE_MORE_SERVICE;
    		}
    
    		if (m == SSL_ERROR_WANT_WRITE || SSL_want_write(wsi->tls.ssl)) {
    
    			lwsl_debug("%s: WANT_WRITE\n", __func__);
    			lwsl_debug("%p: LWS_SSL_CAPABLE_MORE_SERVICE\n", wsi);
    			return LWS_SSL_CAPABLE_MORE_SERVICE;
    		}
    		wsi->socket_is_permanently_unusable = 1;
    
    		return LWS_SSL_CAPABLE_ERROR;
    	}
    
    	lws_stats_atomic_bump(context, pt, LWSSTATS_B_READ, n);
    
    	if (wsi->vhost)
    		wsi->vhost->conn_stats.rx += n;
    
    	/*
    	 * if it was our buffer that limited what we read,
    	 * check if SSL has additional data pending inside SSL buffers.
    	 *
    	 * Because these won't signal at the network layer with POLLIN
    	 * and if we don't realize, this data will sit there forever
    	 */
    	if (n != len)
    		goto bail;
    
    	if (SSL_pending(wsi->tls.ssl) &&
    	    lws_dll_is_null(&wsi->tls.pending_tls_list)) {
    
    		lws_dll_lws_add_front(&wsi->tls.pending_tls_list,
    				      &pt->tls.pending_tls_head);
    	}
    
    
    	return n;
    bail:
    	lws_ssl_remove_wsi_from_buffered_list(wsi);
    
    	return n;
    }
    
    LWS_VISIBLE int
    lws_ssl_pending(struct lws *wsi)
    {
    
    	return SSL_pending(wsi->tls.ssl);
    
    }
    
    LWS_VISIBLE int
    lws_ssl_capable_write(struct lws *wsi, unsigned char *buf, int len)
    {
    	int n, m;
    
    
    		return lws_ssl_capable_write_no_ssl(wsi, buf, len);
    
    
    	n = SSL_write(wsi->tls.ssl, buf, len);
    
    	m = SSL_get_error(wsi->tls.ssl, n);
    
    	if (m != SSL_ERROR_SYSCALL) {
    
    		if (m == SSL_ERROR_WANT_READ || SSL_want_read(wsi->tls.ssl)) {
    
    			lwsl_notice("%s: want read\n", __func__);
    
    			return LWS_SSL_CAPABLE_MORE_SERVICE;
    		}
    
    
    		if (m == SSL_ERROR_WANT_WRITE || SSL_want_write(wsi->tls.ssl)) {
    
    			lws_set_blocking_send(wsi);
    
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    			lwsl_debug("%s: want write\n", __func__);
    
    
    			return LWS_SSL_CAPABLE_MORE_SERVICE;
    		}
    	}
    
    	lwsl_debug("%s failed: %d\n",__func__, m);
    	wsi->socket_is_permanently_unusable = 1;
    
    	return LWS_SSL_CAPABLE_ERROR;
    }
    
    int openssl_SSL_CTX_private_data_index;
    
    void
    lws_ssl_info_callback(const SSL *ssl, int where, int ret)
    {
    	struct lws *wsi;
    	struct lws_context *context;
    	struct lws_ssl_info si;
    
    	context = (struct lws_context *)SSL_CTX_get_ex_data(
    					SSL_get_SSL_CTX(ssl),
    					openssl_SSL_CTX_private_data_index);
    	if (!context)
    		return;
    	wsi = wsi_from_fd(context, SSL_get_fd(ssl));
    	if (!wsi)
    		return;
    
    
    	if (!(where & wsi->vhost->tls.ssl_info_event_mask))
    
    		return;
    
    	si.where = where;
    	si.ret = ret;
    
    	if (user_callback_handle_rxflow(wsi->protocol->callback,
    					wsi, LWS_CALLBACK_SSL_INFO,
    					wsi->user_space, &si, 0))
    		lws_set_timeout(wsi, PENDING_TIMEOUT_KILLED_BY_SSL_INFO, -1);
    }
    
    
    LWS_VISIBLE int
    lws_ssl_close(struct lws *wsi)
    {
    	lws_sockfd_type n;
    
    
    		return 0; /* not handled */
    
    #if defined (LWS_HAVE_SSL_SET_INFO_CALLBACK)
    	/* kill ssl callbacks, becausse we will remove the fd from the
    	 * table linking it to the wsi
    	 */
    
    	if (wsi->vhost->tls.ssl_info_event_mask)
    		SSL_set_info_callback(wsi->tls.ssl, NULL);
    
    	if (!wsi->socket_is_permanently_unusable)
    
    	compatible_close(n);
    
    	SSL_free(wsi->tls.ssl);
    	wsi->tls.ssl = NULL;
    
    	if (!lwsi_role_client(wsi) &&
    
    	    wsi->context->simultaneous_ssl_restriction &&
    
    	    wsi->context->simultaneous_ssl-- ==
    			    wsi->context->simultaneous_ssl_restriction)
    		/* we made space and can do an accept */
    		lws_gate_accepts(wsi->context, 1);
    
    #if defined(LWS_WITH_STATS)
    	wsi->context->updated = 1;
    #endif
    
    	return 1; /* handled */
    }
    
    void
    lws_ssl_SSL_CTX_destroy(struct lws_vhost *vhost)
    {
    
    	if (vhost->tls.ssl_ctx)
    		SSL_CTX_free(vhost->tls.ssl_ctx);
    
    	if (!vhost->tls.user_supplied_ssl_ctx && vhost->tls.ssl_client_ctx)
    		SSL_CTX_free(vhost->tls.ssl_client_ctx);
    
    #if defined(LWS_WITH_ACME)
    
    	lws_tls_acme_sni_cert_destroy(vhost);
    
    }
    
    void
    lws_ssl_context_destroy(struct lws_context *context)
    {
    }
    
    lws_tls_ctx *
    lws_tls_ctx_from_wsi(struct lws *wsi)
    {
    
    	return SSL_get_SSL_CTX(wsi->tls.ssl);
    
    }
    
    enum lws_ssl_capable_status
    
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    __lws_tls_shutdown(struct lws *wsi)
    
    	int n = SSL_shutdown(wsi->tls.ssl);
    
    
    	lwsl_debug("SSL_shutdown=%d for fd %d\n", n, wsi->desc.sockfd);
    
    	switch (n) {
    	case 1: /* successful completion */
    		n = shutdown(wsi->desc.sockfd, SHUT_WR);
    		return LWS_SSL_CAPABLE_DONE;
    
    	case 0: /* needs a retry */
    
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    		__lws_change_pollfd(wsi, 0, LWS_POLLIN);
    
    		return LWS_SSL_CAPABLE_MORE_SERVICE;
    
    	default: /* fatal error, or WANT */
    
    		n = SSL_get_error(wsi->tls.ssl, n);
    
    		if (n != SSL_ERROR_SYSCALL && n != SSL_ERROR_SSL) {
    
    			if (SSL_want_read(wsi->tls.ssl)) {
    
    				lwsl_debug("(wants read)\n");
    
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    				__lws_change_pollfd(wsi, 0, LWS_POLLIN);
    
    				return LWS_SSL_CAPABLE_MORE_SERVICE_READ;
    			}
    
    			if (SSL_want_write(wsi->tls.ssl)) {
    
    				lwsl_debug("(wants write)\n");
    
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    				__lws_change_pollfd(wsi, 0, LWS_POLLOUT);
    
    				return LWS_SSL_CAPABLE_MORE_SERVICE_WRITE;
    			}
    		}
    		return LWS_SSL_CAPABLE_ERROR;
    	}
    }
    
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    static time_t
    lws_tls_mbedtls_time_to_unix(mbedtls_x509_time *xtime)
    {
    	struct tm t;
    
    	if (!xtime || !xtime->year || xtime->year < 0)
    		return (time_t)(long long)-1;
    
    	memset(&t, 0, sizeof(t));
    
    	t.tm_year = xtime->year - 1900;
    	t.tm_mon = xtime->mon - 1; /* mbedtls months are 1+, tm are 0+ */
    	t.tm_mday = xtime->day - 1; /* mbedtls days are 1+, tm are 0+ */
    	t.tm_hour = xtime->hour;
    	t.tm_min = xtime->min;
    	t.tm_sec = xtime->sec;
    	t.tm_isdst = -1;
    
    	return mktime(&t);
    }
    
    static int
    lws_tls_mbedtls_get_x509_name(mbedtls_x509_name *name,
    			      union lws_tls_cert_info_results *buf, size_t len)
    {
    	while (name) {
    		if (MBEDTLS_OID_CMP(MBEDTLS_OID_AT_CN, &name->oid)) {
    			name = name->next;
    			continue;
    		}
    
    		if (len - 1 < name->val.len)
    			return -1;
    
    		memcpy(&buf->ns.name[0], name->val.p, name->val.len);
    		buf->ns.name[name->val.len] = '\0';
    		buf->ns.len = name->val.len;
    
    		return 0;
    	}
    
    	return -1;
    }
    
    static int
    lws_tls_mbedtls_cert_info(mbedtls_x509_crt *x509, enum lws_tls_cert_info type,
    			  union lws_tls_cert_info_results *buf, size_t len)
    {
    	if (!x509)
    		return -1;
    
    	switch (type) {
    	case LWS_TLS_CERT_INFO_VALIDITY_FROM:
    		buf->time = lws_tls_mbedtls_time_to_unix(&x509->valid_from);
    		if (buf->time == (time_t)(long long)-1)
    			return -1;
    		break;
    
    	case LWS_TLS_CERT_INFO_VALIDITY_TO:
    		buf->time = lws_tls_mbedtls_time_to_unix(&x509->valid_to);
    		if (buf->time == (time_t)(long long)-1)
    			return -1;
    		break;
    
    	case LWS_TLS_CERT_INFO_COMMON_NAME:
    		return lws_tls_mbedtls_get_x509_name(&x509->subject, buf, len);
    
    	case LWS_TLS_CERT_INFO_ISSUER_NAME:
    		return lws_tls_mbedtls_get_x509_name(&x509->issuer, buf, len);
    
    	case LWS_TLS_CERT_INFO_USAGE:
    		buf->usage = x509->key_usage;
    		break;
    
    
    	case LWS_TLS_CERT_INFO_OPAQUE_PUBLIC_KEY:
    	{
    		char *p = buf->ns.name;
    		size_t r = len, u;
    
    		switch (mbedtls_pk_get_type(&x509->pk)) {
    		case MBEDTLS_PK_RSA:
    		{
    			mbedtls_rsa_context *rsa = mbedtls_pk_rsa(x509->pk);
    
    			if (mbedtls_mpi_write_string(&rsa->N, 16, p, r, &u))
    				return -1;
    			r -= u;
    			p += u;
    			if (mbedtls_mpi_write_string(&rsa->E, 16, p, r, &u))
    				return -1;
    
    			p += u;
    			buf->ns.len = lws_ptr_diff(p, buf->ns.name);
    			break;
    		}
    		case MBEDTLS_PK_ECKEY:
    		{
    			mbedtls_ecp_keypair *ecp = mbedtls_pk_ec(x509->pk);
    
    			if (mbedtls_mpi_write_string(&ecp->Q.X, 16, p, r, &u))
    				 return -1;
    			r -= u;
    			p += u;
    			if (mbedtls_mpi_write_string(&ecp->Q.Y, 16, p, r, &u))
    				 return -1;
    			r -= u;
    			p += u;
    			if (mbedtls_mpi_write_string(&ecp->Q.Z, 16, p, r, &u))
    				 return -1;
    			p += u;
    			buf->ns.len = lws_ptr_diff(p, buf->ns.name);
    			break;
    		}
    		default:
    			lwsl_notice("%s: x509 has unsupported pubkey type %d\n",
    				    __func__,
    				    mbedtls_pk_get_type(&x509->pk));
    
    			return -1;
    		}
    		break;
    	}
    
    
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    	}
    
    	return 0;
    }
    
    LWS_VISIBLE LWS_EXTERN int
    lws_tls_vhost_cert_info(struct lws_vhost *vhost, enum lws_tls_cert_info type,
    		        union lws_tls_cert_info_results *buf, size_t len)
    {
    
    	mbedtls_x509_crt *x509 = ssl_ctx_get_mbedtls_x509_crt(vhost->tls.ssl_ctx);
    
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    	return lws_tls_mbedtls_cert_info(x509, type, buf, len);
    }
    
    LWS_VISIBLE int
    lws_tls_peer_cert_info(struct lws *wsi, enum lws_tls_cert_info type,
    		       union lws_tls_cert_info_results *buf, size_t len)
    {
    
    	mbedtls_x509_crt *x509;
    
    	wsi = lws_get_network_wsi(wsi);
    
    
    	x509 = ssl_get_peer_mbedtls_x509_crt(wsi->tls.ssl);
    
    	if (!x509)
    		return -1;
    
    	switch (type) {
    	case LWS_TLS_CERT_INFO_VERIFIED:
    
    		buf->verified = SSL_get_verify_result(wsi->tls.ssl) == X509_V_OK;
    
    		return 0;
    	default:
    		return lws_tls_mbedtls_cert_info(x509, type, buf, len);
    	}
    
    	return -1;
    
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    }
    
    
    static int
    tops_fake_POLLIN_for_buffered_mbedtls(struct lws_context_per_thread *pt)
    {
    	return lws_tls_fake_POLLIN_for_buffered(pt);
    }
    
    
    static int
    tops_periodic_housekeeping_mbedtls(struct lws_context *context, time_t now)
    {
    	int n;
    
    	n = lws_compare_time_t(context, now, context->tls.last_cert_check_s);
    	if ((!context->tls.last_cert_check_s || n > (24 * 60 * 60)) &&
    	    !lws_tls_check_all_cert_lifetimes(context))
    		context->tls.last_cert_check_s = now;
    
    	return 0;
    }
    
    
    const struct lws_tls_ops tls_ops_mbedtls = {
    	/* fake_POLLIN_for_buffered */	tops_fake_POLLIN_for_buffered_mbedtls,
    
    	/* periodic_housekeeping */	tops_periodic_housekeeping_mbedtls,