363 lines
12 KiB
C
363 lines
12 KiB
C
/*
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* TLS/SSL Protocol
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* Copyright (c) 2018 Thomas Volkert
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <mbedtls/version.h>
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#include <mbedtls/ctr_drbg.h>
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#include <mbedtls/entropy.h>
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#include <mbedtls/net_sockets.h>
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#include <mbedtls/platform.h>
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#include <mbedtls/ssl.h>
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#include <mbedtls/x509_crt.h>
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#include "avformat.h"
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#include "internal.h"
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#include "url.h"
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#include "tls.h"
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#include "libavutil/parseutils.h"
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typedef struct TLSContext {
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const AVClass *class;
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TLSShared tls_shared;
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mbedtls_ssl_context ssl_context;
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mbedtls_ssl_config ssl_config;
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mbedtls_entropy_context entropy_context;
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mbedtls_ctr_drbg_context ctr_drbg_context;
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mbedtls_x509_crt ca_cert;
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mbedtls_x509_crt own_cert;
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mbedtls_pk_context priv_key;
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char *priv_key_pw;
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} TLSContext;
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#define OFFSET(x) offsetof(TLSContext, x)
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static int tls_close(URLContext *h)
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{
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TLSContext *tls_ctx = h->priv_data;
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mbedtls_ssl_close_notify(&tls_ctx->ssl_context);
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mbedtls_pk_free(&tls_ctx->priv_key);
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mbedtls_x509_crt_free(&tls_ctx->ca_cert);
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mbedtls_x509_crt_free(&tls_ctx->own_cert);
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mbedtls_ssl_free(&tls_ctx->ssl_context);
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mbedtls_ssl_config_free(&tls_ctx->ssl_config);
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mbedtls_ctr_drbg_free(&tls_ctx->ctr_drbg_context);
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mbedtls_entropy_free(&tls_ctx->entropy_context);
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ffurl_closep(&tls_ctx->tls_shared.tcp);
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return 0;
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}
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static int handle_transport_error(URLContext *h, const char* func_name, int react_on_eagain, int ret)
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{
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switch (ret) {
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case AVERROR(EAGAIN):
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return react_on_eagain;
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case AVERROR_EXIT:
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return 0;
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case AVERROR(EPIPE):
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case AVERROR(ECONNRESET):
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return MBEDTLS_ERR_NET_CONN_RESET;
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default:
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av_log(h, AV_LOG_ERROR, "%s returned 0x%x\n", func_name, ret);
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errno = EIO;
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return MBEDTLS_ERR_NET_SEND_FAILED;
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}
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}
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static int mbedtls_send(void *ctx, const unsigned char *buf, size_t len)
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{
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URLContext *h = (URLContext*) ctx;
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int ret = ffurl_write(h, buf, len);
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if (ret >= 0)
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return ret;
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if (h->max_packet_size && len > h->max_packet_size)
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return MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL;
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return handle_transport_error(h, "ffurl_write", MBEDTLS_ERR_SSL_WANT_WRITE, ret);
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}
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static int mbedtls_recv(void *ctx, unsigned char *buf, size_t len)
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{
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URLContext *h = (URLContext*) ctx;
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int ret = ffurl_read(h, buf, len);
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if (ret >= 0)
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return ret;
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if (h->max_packet_size && len > h->max_packet_size)
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return MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL;
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return handle_transport_error(h, "ffurl_read", MBEDTLS_ERR_SSL_WANT_READ, ret);
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}
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static void handle_pk_parse_error(URLContext *h, int ret)
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{
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switch (ret) {
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case MBEDTLS_ERR_PK_FILE_IO_ERROR:
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av_log(h, AV_LOG_ERROR, "Read of key file failed. Is it actually there, are the access permissions correct?\n");
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break;
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case MBEDTLS_ERR_PK_PASSWORD_REQUIRED:
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av_log(h, AV_LOG_ERROR, "A password for the private key is missing.\n");
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break;
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case MBEDTLS_ERR_PK_PASSWORD_MISMATCH:
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av_log(h, AV_LOG_ERROR, "The given password for the private key is wrong.\n");
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break;
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default:
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av_log(h, AV_LOG_ERROR, "mbedtls_pk_parse_key returned -0x%x\n", -ret);
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break;
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}
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}
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static void handle_handshake_error(URLContext *h, int ret)
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{
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switch (ret) {
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#if MBEDTLS_VERSION_MAJOR < 3
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case MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE:
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av_log(h, AV_LOG_ERROR, "None of the common ciphersuites is usable. Was the local certificate correctly set?\n");
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break;
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#else
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case MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE:
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av_log(h, AV_LOG_ERROR, "TLS handshake failed.\n");
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break;
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#endif
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case MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE:
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av_log(h, AV_LOG_ERROR, "A fatal alert message was received from the peer, has the peer a correct certificate?\n");
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break;
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case MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED:
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av_log(h, AV_LOG_ERROR, "No CA chain is set, but required to operate. Was the CA correctly set?\n");
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break;
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case MBEDTLS_ERR_NET_CONN_RESET:
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av_log(h, AV_LOG_ERROR, "TLS handshake was aborted by peer.\n");
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break;
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default:
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av_log(h, AV_LOG_ERROR, "mbedtls_ssl_handshake returned -0x%x\n", -ret);
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break;
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}
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}
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static void parse_options(TLSContext *tls_ctxc, const char *uri)
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{
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char buf[1024];
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const char *p = strchr(uri, '?');
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if (!p)
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return;
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if (!tls_ctxc->priv_key_pw && av_find_info_tag(buf, sizeof(buf), "key_password", p))
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tls_ctxc->priv_key_pw = av_strdup(buf);
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}
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static int tls_open(URLContext *h, const char *uri, int flags, AVDictionary **options)
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{
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TLSContext *tls_ctx = h->priv_data;
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TLSShared *shr = &tls_ctx->tls_shared;
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uint32_t verify_res_flags;
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int ret;
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// parse additional options
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parse_options(tls_ctx, uri);
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if ((ret = ff_tls_open_underlying(shr, h, uri, options)) < 0)
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goto fail;
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mbedtls_ssl_init(&tls_ctx->ssl_context);
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mbedtls_ssl_config_init(&tls_ctx->ssl_config);
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mbedtls_entropy_init(&tls_ctx->entropy_context);
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mbedtls_ctr_drbg_init(&tls_ctx->ctr_drbg_context);
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mbedtls_x509_crt_init(&tls_ctx->ca_cert);
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mbedtls_pk_init(&tls_ctx->priv_key);
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// load trusted CA
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if (shr->ca_file) {
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if ((ret = mbedtls_x509_crt_parse_file(&tls_ctx->ca_cert, shr->ca_file)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_x509_crt_parse_file for CA cert returned %d\n", ret);
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goto fail;
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}
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}
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// load own certificate
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if (shr->cert_file) {
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if ((ret = mbedtls_x509_crt_parse_file(&tls_ctx->own_cert, shr->cert_file)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_x509_crt_parse_file for own cert returned %d\n", ret);
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goto fail;
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}
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}
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// seed the random number generator
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if ((ret = mbedtls_ctr_drbg_seed(&tls_ctx->ctr_drbg_context,
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mbedtls_entropy_func,
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&tls_ctx->entropy_context,
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NULL, 0)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_ctr_drbg_seed returned %d\n", ret);
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goto fail;
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}
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// load key file
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if (shr->key_file) {
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if ((ret = mbedtls_pk_parse_keyfile(&tls_ctx->priv_key,
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shr->key_file,
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tls_ctx->priv_key_pw
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#if MBEDTLS_VERSION_MAJOR >= 3
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, mbedtls_ctr_drbg_random,
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&tls_ctx->ctr_drbg_context
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#endif
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)) != 0) {
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handle_pk_parse_error(h, ret);
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goto fail;
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}
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}
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if ((ret = mbedtls_ssl_config_defaults(&tls_ctx->ssl_config,
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shr->listen ? MBEDTLS_SSL_IS_SERVER : MBEDTLS_SSL_IS_CLIENT,
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MBEDTLS_SSL_TRANSPORT_STREAM,
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MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_ssl_config_defaults returned %d\n", ret);
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goto fail;
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}
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mbedtls_ssl_conf_authmode(&tls_ctx->ssl_config,
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shr->ca_file ? MBEDTLS_SSL_VERIFY_REQUIRED : MBEDTLS_SSL_VERIFY_NONE);
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mbedtls_ssl_conf_rng(&tls_ctx->ssl_config, mbedtls_ctr_drbg_random, &tls_ctx->ctr_drbg_context);
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mbedtls_ssl_conf_ca_chain(&tls_ctx->ssl_config, &tls_ctx->ca_cert, NULL);
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// set own certificate and private key
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if ((ret = mbedtls_ssl_conf_own_cert(&tls_ctx->ssl_config, &tls_ctx->own_cert, &tls_ctx->priv_key)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_ssl_conf_own_cert returned %d\n", ret);
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goto fail;
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}
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if ((ret = mbedtls_ssl_setup(&tls_ctx->ssl_context, &tls_ctx->ssl_config)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_ssl_setup returned %d\n", ret);
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goto fail;
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}
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if (!shr->listen && !shr->numerichost) {
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if ((ret = mbedtls_ssl_set_hostname(&tls_ctx->ssl_context, shr->host)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_ssl_set_hostname returned %d\n", ret);
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goto fail;
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}
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}
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// set I/O functions to use FFmpeg internal code for transport layer
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mbedtls_ssl_set_bio(&tls_ctx->ssl_context, shr->tcp, mbedtls_send, mbedtls_recv, NULL);
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// ssl handshake
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while ((ret = mbedtls_ssl_handshake(&tls_ctx->ssl_context)) != 0) {
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if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
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handle_handshake_error(h, ret);
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goto fail;
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}
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}
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if (shr->verify) {
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// check the result of the certificate verification
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if ((verify_res_flags = mbedtls_ssl_get_verify_result(&tls_ctx->ssl_context)) != 0) {
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av_log(h, AV_LOG_ERROR, "mbedtls_ssl_get_verify_result reported problems "\
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"with the certificate verification, returned flags: %u\n",
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verify_res_flags);
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if (verify_res_flags & MBEDTLS_X509_BADCERT_NOT_TRUSTED)
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av_log(h, AV_LOG_ERROR, "The certificate is not correctly signed by the trusted CA.\n");
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goto fail;
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}
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}
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return 0;
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fail:
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tls_close(h);
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return AVERROR(EIO);
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}
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static int handle_tls_error(URLContext *h, const char* func_name, int ret)
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{
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switch (ret) {
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case MBEDTLS_ERR_SSL_WANT_READ:
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case MBEDTLS_ERR_SSL_WANT_WRITE:
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return AVERROR(EAGAIN);
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case MBEDTLS_ERR_NET_SEND_FAILED:
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case MBEDTLS_ERR_NET_RECV_FAILED:
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return AVERROR(EIO);
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case MBEDTLS_ERR_NET_CONN_RESET:
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case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
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av_log(h, AV_LOG_WARNING, "%s reported connection reset by peer\n", func_name);
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return AVERROR_EOF;
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default:
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av_log(h, AV_LOG_ERROR, "%s returned -0x%x\n", func_name, -ret);
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return AVERROR(EIO);
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}
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}
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static int tls_read(URLContext *h, uint8_t *buf, int size)
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{
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TLSContext *tls_ctx = h->priv_data;
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int ret;
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if ((ret = mbedtls_ssl_read(&tls_ctx->ssl_context, buf, size)) > 0) {
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// return read length
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return ret;
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}
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return handle_tls_error(h, "mbedtls_ssl_read", ret);
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}
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static int tls_write(URLContext *h, const uint8_t *buf, int size)
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{
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TLSContext *tls_ctx = h->priv_data;
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int ret;
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if ((ret = mbedtls_ssl_write(&tls_ctx->ssl_context, buf, size)) > 0) {
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// return written length
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return ret;
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}
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return handle_tls_error(h, "mbedtls_ssl_write", ret);
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}
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static int tls_get_file_handle(URLContext *h)
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{
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TLSContext *c = h->priv_data;
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return ffurl_get_file_handle(c->tls_shared.tcp);
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}
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static const AVOption options[] = {
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TLS_COMMON_OPTIONS(TLSContext, tls_shared), \
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{"key_password", "Password for the private key file", OFFSET(priv_key_pw), AV_OPT_TYPE_STRING, .flags = TLS_OPTFL }, \
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{ NULL }
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};
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static const AVClass tls_class = {
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.class_name = "tls",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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const URLProtocol ff_tls_protocol = {
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.name = "tls",
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.url_open2 = tls_open,
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.url_read = tls_read,
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.url_write = tls_write,
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.url_close = tls_close,
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.url_get_file_handle = tls_get_file_handle,
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.priv_data_size = sizeof(TLSContext),
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.flags = URL_PROTOCOL_FLAG_NETWORK,
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.priv_data_class = &tls_class,
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};
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