FFmpeg/libavformat/tls_securetransport.c
Aman Gupta 9c8922acad This fixes a deadlock while reading a chunked https response, if
multiple_requests=1 is also set. Without an EOF to signal the end of
the last chunk, tls_read gets stuck forever trying to read more data
than is available. This occurs with the http protocol reproducibly,
because http.c always reads 4kb at a time, and the last chunk of an
http response is often much smaller.

After this commit, tls_read always returns any buffered plaintext
first before attempting to read more encrypted data off the
underlying tcp socket.

Signed-off-by: Rodger Combs <rodger.combs@gmail.com>
2017-11-13 15:04:55 -06:00

423 lines
12 KiB
C

/*
* Copyright (c) 2015 Rodger Combs
*
* 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
*/
#include <errno.h>
#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#include "network.h"
#include "os_support.h"
#include "url.h"
#include "tls.h"
#include "libavcodec/internal.h"
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include <Security/Security.h>
#include <Security/SecureTransport.h>
#include <CoreFoundation/CoreFoundation.h>
// We use a private API call here; it's good enough for WebKit.
SecIdentityRef SecIdentityCreate(CFAllocatorRef allocator, SecCertificateRef certificate, SecKeyRef privateKey);
#define ioErr -36
typedef struct TLSContext {
const AVClass *class;
TLSShared tls_shared;
SSLContextRef ssl_context;
CFArrayRef ca_array;
int lastErr;
} TLSContext;
static int print_tls_error(URLContext *h, int ret)
{
TLSContext *c = h->priv_data;
switch (ret) {
case errSSLWouldBlock:
return AVERROR(EAGAIN);
case errSSLXCertChainInvalid:
av_log(h, AV_LOG_ERROR, "Invalid certificate chain\n");
return AVERROR(EIO);
case ioErr:
return c->lastErr;
default:
av_log(h, AV_LOG_ERROR, "IO Error: %i\n", ret);
return AVERROR(EIO);
}
return AVERROR(EIO);
}
static int import_pem(URLContext *h, char *path, CFArrayRef *array)
{
#if !HAVE_SECITEMIMPORT
return AVERROR_PATCHWELCOME;
#else
AVIOContext *s = NULL;
CFDataRef data = NULL;
int64_t ret = 0;
char *buf = NULL;
SecExternalFormat format = kSecFormatPEMSequence;
SecExternalFormat type = kSecItemTypeAggregate;
CFStringRef pathStr = CFStringCreateWithCString(NULL, path, 0x08000100);
if (!pathStr) {
ret = AVERROR(ENOMEM);
goto end;
}
if ((ret = ffio_open_whitelist(&s, path, AVIO_FLAG_READ,
&h->interrupt_callback, NULL,
h->protocol_whitelist, h->protocol_blacklist)) < 0)
goto end;
if ((ret = avio_size(s)) < 0)
goto end;
if (ret == 0) {
ret = AVERROR_INVALIDDATA;
goto end;
}
if (!(buf = av_malloc(ret))) {
ret = AVERROR(ENOMEM);
goto end;
}
if ((ret = avio_read(s, buf, ret)) < 0)
goto end;
data = CFDataCreate(kCFAllocatorDefault, buf, ret);
if (SecItemImport(data, pathStr, &format, &type,
0, NULL, NULL, array) != noErr || !array) {
ret = AVERROR_UNKNOWN;
goto end;
}
if (CFArrayGetCount(*array) == 0) {
ret = AVERROR_INVALIDDATA;
goto end;
}
end:
av_free(buf);
if (pathStr)
CFRelease(pathStr);
if (data)
CFRelease(data);
if (s)
avio_close(s);
return ret;
#endif
}
static int load_ca(URLContext *h)
{
TLSContext *c = h->priv_data;
int ret = 0;
CFArrayRef array = NULL;
if ((ret = import_pem(h, c->tls_shared.ca_file, &array)) < 0)
goto end;
if (!(c->ca_array = CFRetain(array))) {
ret = AVERROR(ENOMEM);
goto end;
}
end:
if (array)
CFRelease(array);
return ret;
}
static int load_cert(URLContext *h)
{
TLSContext *c = h->priv_data;
int ret = 0;
CFArrayRef certArray = NULL;
CFArrayRef keyArray = NULL;
SecIdentityRef id = NULL;
CFMutableArrayRef outArray = NULL;
if ((ret = import_pem(h, c->tls_shared.cert_file, &certArray)) < 0)
goto end;
if ((ret = import_pem(h, c->tls_shared.key_file, &keyArray)) < 0)
goto end;
if (!(id = SecIdentityCreate(kCFAllocatorDefault,
(SecCertificateRef)CFArrayGetValueAtIndex(certArray, 0),
(SecKeyRef)CFArrayGetValueAtIndex(keyArray, 0)))) {
ret = AVERROR_UNKNOWN;
goto end;
}
if (!(outArray = CFArrayCreateMutableCopy(kCFAllocatorDefault, 0, certArray))) {
ret = AVERROR(ENOMEM);
goto end;
}
CFArraySetValueAtIndex(outArray, 0, id);
SSLSetCertificate(c->ssl_context, outArray);
end:
if (certArray)
CFRelease(certArray);
if (keyArray)
CFRelease(keyArray);
if (outArray)
CFRelease(outArray);
if (id)
CFRelease(id);
return ret;
}
static OSStatus tls_read_cb(SSLConnectionRef connection, void *data, size_t *dataLength)
{
URLContext *h = (URLContext*)connection;
TLSContext *c = h->priv_data;
size_t requested = *dataLength;
int read = ffurl_read(c->tls_shared.tcp, data, requested);
if (read <= 0) {
*dataLength = 0;
switch(AVUNERROR(read)) {
case ENOENT:
case 0:
return errSSLClosedGraceful;
case ECONNRESET:
return errSSLClosedAbort;
case EAGAIN:
return errSSLWouldBlock;
default:
c->lastErr = read;
return ioErr;
}
} else {
*dataLength = read;
if (read < requested)
return errSSLWouldBlock;
else
return noErr;
}
}
static OSStatus tls_write_cb(SSLConnectionRef connection, const void *data, size_t *dataLength)
{
URLContext *h = (URLContext*)connection;
TLSContext *c = h->priv_data;
int written = ffurl_write(c->tls_shared.tcp, data, *dataLength);
if (written <= 0) {
*dataLength = 0;
switch(AVUNERROR(written)) {
case EAGAIN:
return errSSLWouldBlock;
default:
c->lastErr = written;
return ioErr;
}
} else {
*dataLength = written;
return noErr;
}
}
static int tls_close(URLContext *h)
{
TLSContext *c = h->priv_data;
if (c->ssl_context) {
SSLClose(c->ssl_context);
CFRelease(c->ssl_context);
}
if (c->ca_array)
CFRelease(c->ca_array);
if (c->tls_shared.tcp)
ffurl_close(c->tls_shared.tcp);
return 0;
}
#define CHECK_ERROR(func, ...) do { \
OSStatus status = func(__VA_ARGS__); \
if (status != noErr) { \
ret = AVERROR_UNKNOWN; \
av_log(h, AV_LOG_ERROR, #func ": Error %i\n", (int)status); \
goto fail; \
} \
} while (0)
static int tls_open(URLContext *h, const char *uri, int flags, AVDictionary **options)
{
TLSContext *c = h->priv_data;
TLSShared *s = &c->tls_shared;
int ret;
if ((ret = ff_tls_open_underlying(s, h, uri, options)) < 0)
goto fail;
c->ssl_context = SSLCreateContext(NULL, s->listen ? kSSLServerSide : kSSLClientSide, kSSLStreamType);
if (!c->ssl_context) {
av_log(h, AV_LOG_ERROR, "Unable to create SSL context\n");
ret = AVERROR(ENOMEM);
goto fail;
}
if (s->ca_file) {
if ((ret = load_ca(h)) < 0)
goto fail;
}
if (s->ca_file || !s->verify)
CHECK_ERROR(SSLSetSessionOption, c->ssl_context, kSSLSessionOptionBreakOnServerAuth, true);
if (s->cert_file)
if ((ret = load_cert(h)) < 0)
goto fail;
CHECK_ERROR(SSLSetPeerDomainName, c->ssl_context, s->host, strlen(s->host));
CHECK_ERROR(SSLSetIOFuncs, c->ssl_context, tls_read_cb, tls_write_cb);
CHECK_ERROR(SSLSetConnection, c->ssl_context, h);
while (1) {
OSStatus status = SSLHandshake(c->ssl_context);
if (status == errSSLServerAuthCompleted) {
SecTrustRef peerTrust;
SecTrustResultType trustResult;
if (!s->verify)
continue;
if (SSLCopyPeerTrust(c->ssl_context, &peerTrust) != noErr) {
ret = AVERROR(ENOMEM);
goto fail;
}
if (SecTrustSetAnchorCertificates(peerTrust, c->ca_array) != noErr) {
ret = AVERROR_UNKNOWN;
goto fail;
}
if (SecTrustEvaluate(peerTrust, &trustResult) != noErr) {
ret = AVERROR_UNKNOWN;
goto fail;
}
if (trustResult == kSecTrustResultProceed ||
trustResult == kSecTrustResultUnspecified) {
// certificate is trusted
status = errSSLWouldBlock; // so we call SSLHandshake again
} else if (trustResult == kSecTrustResultRecoverableTrustFailure) {
// not trusted, for some reason other than being expired
status = errSSLXCertChainInvalid;
} else {
// cannot use this certificate (fatal)
status = errSSLBadCert;
}
if (peerTrust)
CFRelease(peerTrust);
}
if (status == noErr) {
break;
} else if (status != errSSLWouldBlock) {
av_log(h, AV_LOG_ERROR, "Unable to negotiate TLS/SSL session: %i\n", (int)status);
ret = AVERROR(EIO);
goto fail;
}
}
return 0;
fail:
tls_close(h);
return ret;
}
static int map_ssl_error(OSStatus status, size_t processed)
{
switch (status) {
case noErr:
return processed;
case errSSLClosedGraceful:
case errSSLClosedNoNotify:
return 0;
case errSSLWouldBlock:
if (processed > 0)
return processed;
default:
return (int)status;
}
}
static int tls_read(URLContext *h, uint8_t *buf, int size)
{
TLSContext *c = h->priv_data;
size_t available = 0, processed = 0;
int ret;
SSLGetBufferedReadSize(c->ssl_context, &available);
if (available)
size = FFMIN(available, size);
ret = SSLRead(c->ssl_context, buf, size, &processed);
ret = map_ssl_error(ret, processed);
if (ret > 0)
return ret;
if (ret == 0)
return AVERROR_EOF;
return print_tls_error(h, ret);
}
static int tls_write(URLContext *h, const uint8_t *buf, int size)
{
TLSContext *c = h->priv_data;
size_t processed = 0;
int ret = SSLWrite(c->ssl_context, buf, size, &processed);
ret = map_ssl_error(ret, processed);
if (ret > 0)
return ret;
if (ret == 0)
return AVERROR_EOF;
return print_tls_error(h, ret);
}
static int tls_get_file_handle(URLContext *h)
{
TLSContext *c = h->priv_data;
return ffurl_get_file_handle(c->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,
.priv_data_size = sizeof(TLSContext),
.flags = URL_PROTOCOL_FLAG_NETWORK,
.priv_data_class = &tls_class,
};