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ffmpeg/libavformat/tls_schannel.c

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/*
* Copyright (c) 2015 Hendrik Leppkes
*
* This file is part of FFmpeg.
*
* FFmpeg 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; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/** Based on the CURL SChannel module */
#include "libavutil/mem.h"
#include "avformat.h"
#include "internal.h"
#include "network.h"
#include "os_support.h"
#include "url.h"
#include "tls.h"
#define SECURITY_WIN32
#include <windows.h>
#include <security.h>
#include <schnlsp.h>
#define SCHANNEL_INITIAL_BUFFER_SIZE 4096
#define SCHANNEL_FREE_BUFFER_SIZE 1024
/* mingw does not define this symbol */
#ifndef SECBUFFER_ALERT
#define SECBUFFER_ALERT 17
#endif
typedef struct TLSContext {
const AVClass *class;
TLSShared tls_shared;
CredHandle cred_handle;
TimeStamp cred_timestamp;
CtxtHandle ctxt_handle;
TimeStamp ctxt_timestamp;
ULONG request_flags;
ULONG context_flags;
uint8_t *enc_buf;
int enc_buf_size;
int enc_buf_offset;
uint8_t *dec_buf;
int dec_buf_size;
int dec_buf_offset;
SecPkgContext_StreamSizes sizes;
int connected;
int connection_closed;
int sspi_close_notify;
} TLSContext;
static void init_sec_buffer(SecBuffer *buffer, unsigned long type,
void *data, unsigned long size)
{
buffer->cbBuffer = size;
buffer->BufferType = type;
buffer->pvBuffer = data;
}
static void init_sec_buffer_desc(SecBufferDesc *desc, SecBuffer *buffers,
unsigned long buffer_count)
{
desc->ulVersion = SECBUFFER_VERSION;
desc->pBuffers = buffers;
desc->cBuffers = buffer_count;
}
static int tls_shutdown_client(URLContext *h)
{
TLSContext *c = h->priv_data;
TLSShared *s = &c->tls_shared;
int ret;
if (c->connected) {
SecBufferDesc BuffDesc;
SecBuffer Buffer;
SECURITY_STATUS sspi_ret;
SecBuffer outbuf;
SecBufferDesc outbuf_desc;
DWORD dwshut = SCHANNEL_SHUTDOWN;
init_sec_buffer(&Buffer, SECBUFFER_TOKEN, &dwshut, sizeof(dwshut));
init_sec_buffer_desc(&BuffDesc, &Buffer, 1);
sspi_ret = ApplyControlToken(&c->ctxt_handle, &BuffDesc);
if (sspi_ret != SEC_E_OK)
av_log(h, AV_LOG_ERROR, "ApplyControlToken failed\n");
init_sec_buffer(&outbuf, SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer_desc(&outbuf_desc, &outbuf, 1);
sspi_ret = InitializeSecurityContext(&c->cred_handle, &c->ctxt_handle, s->host,
c->request_flags, 0, 0, NULL, 0, &c->ctxt_handle,
&outbuf_desc, &c->context_flags, &c->ctxt_timestamp);
if (sspi_ret == SEC_E_OK || sspi_ret == SEC_I_CONTEXT_EXPIRED) {
s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
ret = ffurl_write(s->tcp, outbuf.pvBuffer, outbuf.cbBuffer);
FreeContextBuffer(outbuf.pvBuffer);
if (ret < 0 || ret != outbuf.cbBuffer)
av_log(h, AV_LOG_ERROR, "Failed to send close message\n");
}
c->connected = 0;
}
return 0;
}
static int tls_close(URLContext *h)
{
TLSContext *c = h->priv_data;
tls_shutdown_client(h);
DeleteSecurityContext(&c->ctxt_handle);
FreeCredentialsHandle(&c->cred_handle);
av_freep(&c->enc_buf);
c->enc_buf_size = c->enc_buf_offset = 0;
av_freep(&c->dec_buf);
c->dec_buf_size = c->dec_buf_offset = 0;
ffurl_closep(&c->tls_shared.tcp);
return 0;
}
static int tls_client_handshake_loop(URLContext *h, int initial)
{
TLSContext *c = h->priv_data;
TLSShared *s = &c->tls_shared;
SECURITY_STATUS sspi_ret;
SecBuffer outbuf[3] = { 0 };
SecBufferDesc outbuf_desc;
SecBuffer inbuf[2];
SecBufferDesc inbuf_desc;
int i, ret = 0, read_data = initial;
if (c->enc_buf == NULL) {
c->enc_buf_offset = 0;
ret = av_reallocp(&c->enc_buf, SCHANNEL_INITIAL_BUFFER_SIZE);
if (ret < 0)
goto fail;
c->enc_buf_size = SCHANNEL_INITIAL_BUFFER_SIZE;
}
if (c->dec_buf == NULL) {
c->dec_buf_offset = 0;
ret = av_reallocp(&c->dec_buf, SCHANNEL_INITIAL_BUFFER_SIZE);
if (ret < 0)
goto fail;
c->dec_buf_size = SCHANNEL_INITIAL_BUFFER_SIZE;
}
while (1) {
if (c->enc_buf_size - c->enc_buf_offset < SCHANNEL_FREE_BUFFER_SIZE) {
c->enc_buf_size = c->enc_buf_offset + SCHANNEL_FREE_BUFFER_SIZE;
ret = av_reallocp(&c->enc_buf, c->enc_buf_size);
if (ret < 0) {
c->enc_buf_size = c->enc_buf_offset = 0;
goto fail;
}
}
if (read_data) {
ret = ffurl_read(c->tls_shared.tcp, c->enc_buf + c->enc_buf_offset,
c->enc_buf_size - c->enc_buf_offset);
if (ret < 0) {
av_log(h, AV_LOG_ERROR, "Failed to read handshake response\n");
goto fail;
}
c->enc_buf_offset += ret;
}
/* input buffers */
init_sec_buffer(&inbuf[0], SECBUFFER_TOKEN, av_malloc(c->enc_buf_offset), c->enc_buf_offset);
init_sec_buffer(&inbuf[1], SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer_desc(&inbuf_desc, inbuf, 2);
if (inbuf[0].pvBuffer == NULL) {
av_log(h, AV_LOG_ERROR, "Failed to allocate input buffer\n");
ret = AVERROR(ENOMEM);
goto fail;
}
memcpy(inbuf[0].pvBuffer, c->enc_buf, c->enc_buf_offset);
/* output buffers */
init_sec_buffer(&outbuf[0], SECBUFFER_TOKEN, NULL, 0);
init_sec_buffer(&outbuf[1], SECBUFFER_ALERT, NULL, 0);
init_sec_buffer(&outbuf[2], SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer_desc(&outbuf_desc, outbuf, 3);
sspi_ret = InitializeSecurityContext(&c->cred_handle, &c->ctxt_handle, s->host, c->request_flags,
0, 0, &inbuf_desc, 0, NULL, &outbuf_desc, &c->context_flags,
&c->ctxt_timestamp);
av_freep(&inbuf[0].pvBuffer);
if (sspi_ret == SEC_E_INCOMPLETE_MESSAGE) {
av_log(h, AV_LOG_DEBUG, "Received incomplete handshake, need more data\n");
read_data = 1;
continue;
}
/* remote requests a client certificate - attempt to continue without one anyway */
if (sspi_ret == SEC_I_INCOMPLETE_CREDENTIALS &&
!(c->request_flags & ISC_REQ_USE_SUPPLIED_CREDS)) {
av_log(h, AV_LOG_VERBOSE, "Client certificate has been requested, ignoring\n");
c->request_flags |= ISC_REQ_USE_SUPPLIED_CREDS;
read_data = 0;
continue;
}
/* continue handshake */
if (sspi_ret == SEC_I_CONTINUE_NEEDED || sspi_ret == SEC_E_OK) {
for (i = 0; i < 3; i++) {
if (outbuf[i].BufferType == SECBUFFER_TOKEN && outbuf[i].cbBuffer > 0) {
ret = ffurl_write(c->tls_shared.tcp, outbuf[i].pvBuffer, outbuf[i].cbBuffer);
if (ret < 0 || ret != outbuf[i].cbBuffer) {
av_log(h, AV_LOG_VERBOSE, "Failed to send handshake data\n");
ret = AVERROR(EIO);
goto fail;
}
}
if (outbuf[i].pvBuffer != NULL) {
FreeContextBuffer(outbuf[i].pvBuffer);
outbuf[i].pvBuffer = NULL;
}
}
} else {
if (sspi_ret == SEC_E_WRONG_PRINCIPAL)
av_log(h, AV_LOG_ERROR, "SNI or certificate check failed\n");
else
av_log(h, AV_LOG_ERROR, "Creating security context failed (0x%lx)\n", sspi_ret);
ret = AVERROR_UNKNOWN;
goto fail;
}
if (inbuf[1].BufferType == SECBUFFER_EXTRA && inbuf[1].cbBuffer > 0) {
if (c->enc_buf_offset > inbuf[1].cbBuffer) {
memmove(c->enc_buf, (c->enc_buf + c->enc_buf_offset) - inbuf[1].cbBuffer,
inbuf[1].cbBuffer);
c->enc_buf_offset = inbuf[1].cbBuffer;
if (sspi_ret == SEC_I_CONTINUE_NEEDED) {
read_data = 0;
continue;
}
}
} else {
c->enc_buf_offset = 0;
}
if (sspi_ret == SEC_I_CONTINUE_NEEDED) {
read_data = 1;
continue;
}
break;
}
return 0;
fail:
/* free any remaining output data */
for (i = 0; i < 3; i++) {
if (outbuf[i].pvBuffer != NULL) {
FreeContextBuffer(outbuf[i].pvBuffer);
outbuf[i].pvBuffer = NULL;
}
}
return ret;
}
static int tls_client_handshake(URLContext *h)
{
TLSContext *c = h->priv_data;
TLSShared *s = &c->tls_shared;
SecBuffer outbuf;
SecBufferDesc outbuf_desc;
SECURITY_STATUS sspi_ret;
int ret;
init_sec_buffer(&outbuf, SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer_desc(&outbuf_desc, &outbuf, 1);
c->request_flags = ISC_REQ_SEQUENCE_DETECT | ISC_REQ_REPLAY_DETECT |
ISC_REQ_CONFIDENTIALITY | ISC_REQ_ALLOCATE_MEMORY |
ISC_REQ_STREAM;
sspi_ret = InitializeSecurityContext(&c->cred_handle, NULL, s->host, c->request_flags, 0, 0,
NULL, 0, &c->ctxt_handle, &outbuf_desc, &c->context_flags,
&c->ctxt_timestamp);
if (sspi_ret != SEC_I_CONTINUE_NEEDED) {
av_log(h, AV_LOG_ERROR, "Unable to create initial security context (0x%lx)\n", sspi_ret);
ret = AVERROR_UNKNOWN;
goto fail;
}
s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
ret = ffurl_write(s->tcp, outbuf.pvBuffer, outbuf.cbBuffer);
FreeContextBuffer(outbuf.pvBuffer);
if (ret < 0 || ret != outbuf.cbBuffer) {
av_log(h, AV_LOG_ERROR, "Failed to send initial handshake data\n");
ret = AVERROR(EIO);
goto fail;
}
return tls_client_handshake_loop(h, 1);
fail:
DeleteSecurityContext(&c->ctxt_handle);
return ret;
}
static int tls_open(URLContext *h, const char *uri, int flags, AVDictionary **options)
{
TLSContext *c = h->priv_data;
TLSShared *s = &c->tls_shared;
SECURITY_STATUS sspi_ret;
SCHANNEL_CRED schannel_cred = { 0 };
int ret;
if ((ret = ff_tls_open_underlying(s, h, uri, options)) < 0)
goto fail;
if (s->listen) {
av_log(h, AV_LOG_ERROR, "TLS Listen Sockets with SChannel is not implemented.\n");
ret = AVERROR(EINVAL);
goto fail;
}
/* SChannel Options */
schannel_cred.dwVersion = SCHANNEL_CRED_VERSION;
if (s->verify)
schannel_cred.dwFlags = SCH_CRED_AUTO_CRED_VALIDATION |
SCH_CRED_REVOCATION_CHECK_CHAIN;
else
schannel_cred.dwFlags = SCH_CRED_MANUAL_CRED_VALIDATION |
SCH_CRED_IGNORE_NO_REVOCATION_CHECK |
SCH_CRED_IGNORE_REVOCATION_OFFLINE;
/* Get credential handle */
sspi_ret = AcquireCredentialsHandle(NULL, (TCHAR *)UNISP_NAME, SECPKG_CRED_OUTBOUND,
NULL, &schannel_cred, NULL, NULL, &c->cred_handle,
&c->cred_timestamp);
if (sspi_ret != SEC_E_OK) {
av_log(h, AV_LOG_ERROR, "Unable to acquire security credentials (0x%lx)\n", sspi_ret);
ret = AVERROR_UNKNOWN;
goto fail;
}
ret = tls_client_handshake(h);
if (ret < 0)
goto fail;
c->connected = 1;
return 0;
fail:
tls_close(h);
return ret;
}
static int tls_read(URLContext *h, uint8_t *buf, int len)
{
TLSContext *c = h->priv_data;
TLSShared *s = &c->tls_shared;
SECURITY_STATUS sspi_ret = SEC_E_OK;
SecBuffer inbuf[4];
SecBufferDesc inbuf_desc;
int size, ret;
int min_enc_buf_size = len + SCHANNEL_FREE_BUFFER_SIZE;
/* If we have some left-over data from previous network activity,
* return it first in case it is enough. It may contain
* data that is required to know whether this connection
* is still required or not, esp. in case of HTTP keep-alive
* connections. */
if (c->dec_buf_offset > 0)
goto cleanup;
if (c->sspi_close_notify)
goto cleanup;
if (!c->connection_closed) {
size = c->enc_buf_size - c->enc_buf_offset;
if (size < SCHANNEL_FREE_BUFFER_SIZE || c->enc_buf_size < min_enc_buf_size) {
c->enc_buf_size = c->enc_buf_offset + SCHANNEL_FREE_BUFFER_SIZE;
if (c->enc_buf_size < min_enc_buf_size)
c->enc_buf_size = min_enc_buf_size;
ret = av_reallocp(&c->enc_buf, c->enc_buf_size);
if (ret < 0) {
c->enc_buf_size = c->enc_buf_offset = 0;
return ret;
}
}
s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
s->tcp->flags |= h->flags & AVIO_FLAG_NONBLOCK;
ret = ffurl_read(s->tcp, c->enc_buf + c->enc_buf_offset,
c->enc_buf_size - c->enc_buf_offset);
if (ret == AVERROR_EOF) {
c->connection_closed = 1;
ret = 0;
} else if (ret == AVERROR(EAGAIN)) {
ret = 0;
} else if (ret < 0) {
av_log(h, AV_LOG_ERROR, "Unable to read from socket\n");
return ret;
}
c->enc_buf_offset += ret;
}
while (c->enc_buf_offset > 0 && sspi_ret == SEC_E_OK) {
/* input buffer */
init_sec_buffer(&inbuf[0], SECBUFFER_DATA, c->enc_buf, c->enc_buf_offset);
/* additional buffers for possible output */
init_sec_buffer(&inbuf[1], SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer(&inbuf[2], SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer(&inbuf[3], SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer_desc(&inbuf_desc, inbuf, 4);
sspi_ret = DecryptMessage(&c->ctxt_handle, &inbuf_desc, 0, NULL);
if (sspi_ret == SEC_E_OK || sspi_ret == SEC_I_RENEGOTIATE ||
sspi_ret == SEC_I_CONTEXT_EXPIRED) {
/* handle decrypted data */
if (inbuf[1].BufferType == SECBUFFER_DATA) {
/* grow buffer if needed */
size = inbuf[1].cbBuffer > SCHANNEL_FREE_BUFFER_SIZE ?
inbuf[1].cbBuffer : SCHANNEL_FREE_BUFFER_SIZE;
if (c->dec_buf_size - c->dec_buf_offset < size || c->dec_buf_size < len) {
c->dec_buf_size = c->dec_buf_offset + size;
if (c->dec_buf_size < len)
c->dec_buf_size = len;
ret = av_reallocp(&c->dec_buf, c->dec_buf_size);
if (ret < 0) {
c->dec_buf_size = c->dec_buf_offset = 0;
return ret;
}
}
/* copy decrypted data to buffer */
size = inbuf[1].cbBuffer;
if (size) {
memcpy(c->dec_buf + c->dec_buf_offset, inbuf[1].pvBuffer, size);
c->dec_buf_offset += size;
}
}
if (inbuf[3].BufferType == SECBUFFER_EXTRA && inbuf[3].cbBuffer > 0) {
if (c->enc_buf_offset > inbuf[3].cbBuffer) {
memmove(c->enc_buf, (c->enc_buf + c->enc_buf_offset) - inbuf[3].cbBuffer,
inbuf[3].cbBuffer);
c->enc_buf_offset = inbuf[3].cbBuffer;
}
} else
c->enc_buf_offset = 0;
if (sspi_ret == SEC_I_RENEGOTIATE) {
if (c->enc_buf_offset) {
av_log(h, AV_LOG_ERROR, "Cannot renegotiate, encrypted data buffer not empty\n");
ret = AVERROR_UNKNOWN;
goto cleanup;
}
av_log(h, AV_LOG_VERBOSE, "Re-negotiating security context\n");
ret = tls_client_handshake_loop(h, 0);
if (ret < 0) {
goto cleanup;
}
sspi_ret = SEC_E_OK;
continue;
} else if (sspi_ret == SEC_I_CONTEXT_EXPIRED) {
c->sspi_close_notify = 1;
if (!c->connection_closed) {
c->connection_closed = 1;
av_log(h, AV_LOG_VERBOSE, "Server closed the connection\n");
}
ret = 0;
goto cleanup;
}
} else if (sspi_ret == SEC_E_INCOMPLETE_MESSAGE) {
ret = AVERROR(EAGAIN);
goto cleanup;
} else {
av_log(h, AV_LOG_ERROR, "Unable to decrypt message (error 0x%x)\n", (unsigned)sspi_ret);
ret = AVERROR(EIO);
goto cleanup;
}
}
ret = 0;
cleanup:
size = FFMIN(len, c->dec_buf_offset);
if (size) {
memcpy(buf, c->dec_buf, size);
memmove(c->dec_buf, c->dec_buf + size, c->dec_buf_offset - size);
c->dec_buf_offset -= size;
return size;
}
if (ret == 0 && !c->connection_closed)
ret = AVERROR(EAGAIN);
return ret < 0 ? ret : AVERROR_EOF;
}
static int tls_write(URLContext *h, const uint8_t *buf, int len)
{
TLSContext *c = h->priv_data;
TLSShared *s = &c->tls_shared;
SECURITY_STATUS sspi_ret;
int ret = 0, data_size;
uint8_t *data = NULL;
SecBuffer outbuf[4];
SecBufferDesc outbuf_desc;
if (c->sizes.cbMaximumMessage == 0) {
sspi_ret = QueryContextAttributes(&c->ctxt_handle, SECPKG_ATTR_STREAM_SIZES, &c->sizes);
if (sspi_ret != SEC_E_OK)
return AVERROR_UNKNOWN;
}
/* limit how much data we can consume */
len = FFMIN(len, c->sizes.cbMaximumMessage);
data_size = c->sizes.cbHeader + len + c->sizes.cbTrailer;
data = av_malloc(data_size);
if (data == NULL)
return AVERROR(ENOMEM);
init_sec_buffer(&outbuf[0], SECBUFFER_STREAM_HEADER,
data, c->sizes.cbHeader);
init_sec_buffer(&outbuf[1], SECBUFFER_DATA,
data + c->sizes.cbHeader, len);
init_sec_buffer(&outbuf[2], SECBUFFER_STREAM_TRAILER,
data + c->sizes.cbHeader + len,
c->sizes.cbTrailer);
init_sec_buffer(&outbuf[3], SECBUFFER_EMPTY, NULL, 0);
init_sec_buffer_desc(&outbuf_desc, outbuf, 4);
memcpy(outbuf[1].pvBuffer, buf, len);
sspi_ret = EncryptMessage(&c->ctxt_handle, 0, &outbuf_desc, 0);
if (sspi_ret == SEC_E_OK) {
len = outbuf[0].cbBuffer + outbuf[1].cbBuffer + outbuf[2].cbBuffer;
s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
s->tcp->flags |= h->flags & AVIO_FLAG_NONBLOCK;
ret = ffurl_write(s->tcp, data, len);
if (ret == AVERROR(EAGAIN)) {
goto done;
} else if (ret < 0 || ret != len) {
ret = AVERROR(EIO);
av_log(h, AV_LOG_ERROR, "Writing encrypted data to socket failed\n");
goto done;
}
} else {
av_log(h, AV_LOG_ERROR, "Encrypting data failed\n");
if (sspi_ret == SEC_E_INSUFFICIENT_MEMORY)
ret = AVERROR(ENOMEM);
else
ret = AVERROR(EIO);
goto done;
}
done:
av_freep(&data);
return ret < 0 ? ret : outbuf[1].cbBuffer;
}
static int tls_get_file_handle(URLContext *h)
{
TLSContext *c = h->priv_data;
return ffurl_get_file_handle(c->tls_shared.tcp);
}
static int tls_get_short_seek(URLContext *h)
{
TLSContext *s = h->priv_data;
return ffurl_get_short_seek(s->tls_shared.tcp);
}
static const AVOption options[] = {
TLS_COMMON_OPTIONS(TLSContext, tls_shared),
{ NULL }
};
static const AVClass tls_class = {
.class_name = "tls",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const URLProtocol ff_tls_protocol = {
.name = "tls",
.url_open2 = tls_open,
.url_read = tls_read,
.url_write = tls_write,
.url_close = tls_close,
.url_get_file_handle = tls_get_file_handle,
.url_get_short_seek = tls_get_short_seek,
.priv_data_size = sizeof(TLSContext),
.flags = URL_PROTOCOL_FLAG_NETWORK,
.priv_data_class = &tls_class,
};
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