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Stop malformed MPO files terminating Kodi, and bounds-check the MP parser #73

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Merged
garbear merged 1 commit into from
Aug 30, 2026
Merged

Stop malformed MPO files terminating Kodi, and bounds-check the MP parser #73

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40 changes: 39 additions & 1 deletion src/MPOPicture.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,9 +10,30 @@

#include "../lib/TinyEXIF/TinyEXIF.h"

#include <csetjmp>
#include <iostream>
#include <kodi/Filesystem.h>

namespace
{

// libjpeg's default error_exit calls exit(), and libmpo installs it via
// jpeg_std_error() without overriding it, so a malformed file terminates Kodi
// rather than failing the decode. mpo_decompress_error_exit() can only replace
// the function pointer, not attach state to it, so the jump target is
// thread-local; each decoder instance is driven from one thread at a time.
thread_local std::jmp_buf s_jpegEscape;

void MpoFatalError(j_common_ptr cinfo)
{
char message[JMSG_LENGTH_MAX] = {};
(*cinfo->err->format_message)(cinfo, message);
kodi::Log(ADDON_LOG_ERROR, "libjpeg: %s", message);
std::longjmp(s_jpegEscape, 1);
}

} // namespace

MPOPicture::MPOPicture(const kodi::addon::IInstanceInfo& instance)
: CInstanceImageDecoder(instance)
{
Expand All @@ -36,8 +57,15 @@ bool MPOPicture::SupportsFile(const std::string& file)

mpo_decompress_struct mpoinfo;
mpo_create_decompress(&mpoinfo);
mpo_decompress_error_exit(&mpoinfo, MpoFatalError);
if (setjmp(s_jpegEscape))
{
mpo_destroy_decompress(&mpoinfo);
return false;
}

mpo_mem_src(&mpoinfo, buffer.data(), buffer.size());
bool ret = mpo_read_header(&mpoinfo);
const bool ret = mpo_read_header(&mpoinfo);
mpo_destroy_decompress(&mpoinfo);
return ret;
}
Expand Down Expand Up @@ -139,6 +167,13 @@ bool MPOPicture::LoadImageFromMemory(const std::string& mimetype,
m_data.resize(bufSize);
std::copy(buffer, buffer + bufSize, m_data.begin());
mpo_create_decompress(&m_mpoinfo);
mpo_decompress_error_exit(&m_mpoinfo, MpoFatalError);
if (setjmp(s_jpegEscape))
{
mpo_destroy_decompress(&m_mpoinfo);
return false;
}

mpo_mem_src(&m_mpoinfo, m_data.data(), m_data.size());
if (!mpo_read_header(&m_mpoinfo))
{
Expand Down Expand Up @@ -169,6 +204,9 @@ bool MPOPicture::Decode(uint8_t* pixels,
return false;
}

if (setjmp(s_jpegEscape))
return false;

size_t image = 0;
while (image < m_images)
{
Expand Down