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RAW: Error out on malformed files

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Internally, LibRaw often doesn't check the return values of various functions. It's not uncommon to find things like:

fseek(ifp, oAtom, SEEK_SET);
szAtom = get4();
... (more read operations without checking the result)

This means is up to us to error our properly when something went wrong. We do that by keeping an error counter and calling IOERROR once we've reached enough errors. IOERROR will throw an exception that will be internally caught by libraw itself.
This commit is contained in:
Mirco Miranda
2025-08-07 22:39:55 +02:00
committed by Albert Astals Cid
parent 480ea8dba0
commit e912a4ac9b
1 changed files with 84 additions and 16 deletions
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100
src/imageformats/raw.cpp
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@ -11,7 +11,6 @@
#include <QColorSpace>
#include <QDateTime>
#include <QDebug>
#include <QImage>
#include <QSet>
#include <QTimeZone>
@ -22,12 +21,24 @@
#include <libraw/libraw.h>
#ifndef RAW_DISABLE_BROKEN_STREAM_PROTECTION
/* The LibRaw_QIODevice stream interrupt the reading of the RAW file if a
* burst of read errors are detected.
* By defining RAW_IGNORE_BROKEN_STREAMS removes this protection, leaving
* LibRaw in complete control of error handling (which is mostly absent).
*/
// #define RAW_DISABLE_BROKEN_STREAM_PROTECTION
#endif
#ifdef QT_DEBUG
// This should be used to exclude the local QIODevice wrapper of the LibRaw_abstract_datastream interface.
// If the result changes then the problem is in the local wrapper and must be corrected.
// WARNING: using the LibRaw's streams instead of the local wrapper from a Qt program falls in the LOCALE
// bug when the RAW file needs the scanf_one() function (e.g. *.MOS files). See also raw_scanf_one().
//#define EXCLUDE_LibRaw_QIODevice // Uncomment this code if you think that the problem is LibRaw_QIODevice (default commented)
/* This should be used to exclude the local QIODevice wrapper of the
* LibRaw_abstract_datastream interface. If the result changes then the problem
* is in the local wrapper and must be corrected.
* WARNING: using the LibRaw's streams instead of the local wrapper from a Qt
* program falls in the LOCALE bug when the RAW file needs the
* scanf_one() function (e.g. *.MOS files). See also raw_scanf_one().
*/
// #define EXCLUDE_LibRaw_QIODevice // Uncomment this code if you think that the problem is LibRaw_QIODevice (default commented)
#endif
namespace // Private.
@ -95,10 +106,46 @@ inline int raw_scanf_one(const QByteArray &ba, const char *fmt, void *val)
*/
class LibRaw_QIODevice : public LibRaw_abstract_datastream
{
inline void incError()
{
// Normally, when read errors occur, a plugin exits with an error.
// Here, given how LibRaw works, we need to be a little more flexible:
// for example, a seek might fail when the library tries to figure out
// what it's reading. We therefore use a dynamic error counting system
// where the error counts heavily, but subsequent successful
// operations can mitigate it.
// If the stream is obviously corrupt, the plugin exits.
m_errorCount += 3;
}
inline void decError()
{
m_errorCount = std::max(m_errorCount - 1, 0);
}
void checkErrors() {
// Internally, LibRaw often doesn't check the return values of various
// functions. It's not uncommon to find things like:
//
// fseek(ifp, oAtom, SEEK_SET);
// szAtom = get4();
//
// which can cause the read to go into an infinite loop on corrupted
// files. I've set the error count to high to avoid these issues.
if (m_errorCount > 10) {
#ifndef RAW_DISABLE_BROKEN_STREAM_PROTECTION
// LibRaw stream classes can throw exceptions that are handled by
// libraw itself (e.g. see implementation of
// LibRaw_bigfile_datastream).
// Every LibRaw function that works on the stream used in this
// plugin is protected by a Try...Catch.
IOERROR(); // defined in libraw_datastream.h
#endif
}
}
public:
explicit LibRaw_QIODevice(QIODevice *device)
: m_device(device)
, m_errorCount(0)
{
m_device = device;
}
virtual ~LibRaw_QIODevice() override
{
@ -109,19 +156,22 @@ public:
}
virtual int read(void *ptr, size_t sz, size_t nmemb) override
{
checkErrors();
qint64 read = 0;
if (sz == 0) {
return 0;
}
auto data = reinterpret_cast<char*>(ptr);
for (qint64 r = 0, size = sz * nmemb; read < size; read += r) {
if (m_device->atEnd()) {
break;
}
r = m_device->read(data + read, size - read);
if (r < 1) {
if (read == 0 || r < 0) {
incError();
}
break;
}
decError();
}
return int(read / sz);
}
@ -131,17 +181,21 @@ public:
}
virtual int seek(INT64 o, int whence) override
{
checkErrors();
auto pos = o;
auto size = m_device->size();
auto siz = size();
if (whence == SEEK_CUR) {
pos = m_device->pos() + o;
pos = tell() + o;
}
if (whence == SEEK_END) {
pos = size + o;
pos = siz + o;
}
if (pos < 0 || m_device->isSequential()) {
if (pos < 0 || pos > siz || m_device->isSequential()) {
incError();
return -1;
}
decError();
return m_device->seek(pos) ? 0 : -1;
}
virtual INT64 tell() override
@ -154,17 +208,24 @@ public:
}
virtual char *gets(char *s, int sz) override
{
checkErrors();
if (m_device->readLine(s, sz) > 0) {
decError();
return s;
}
incError();
return nullptr;
}
virtual int scanf_one(const char *fmt, void *val) override
{
checkErrors();
QByteArray ba;
for (int xcnt = 0; xcnt < 24 && !m_device->atEnd(); ++xcnt) {
char c;
if (!m_device->getChar(&c)) {
incError();
return EOF;
}
if (ba.isEmpty() && (c == ' ' || c == '\t')) {
@ -175,14 +236,19 @@ public:
}
ba.append(c);
}
decError();
return raw_scanf_one(ba, fmt, val);
}
virtual int get_char() override
{
checkErrors();
unsigned char c;
if (!m_device->getChar(reinterpret_cast<char *>(&c))) {
incError();
return EOF;
}
decError();
return int(c);
}
#if (LIBRAW_VERSION < LIBRAW_MAKE_VERSION(0, 21, 0)) || defined(LIBRAW_OLD_VIDEO_SUPPORT)
@ -194,6 +260,8 @@ public:
private:
QIODevice *m_device;
qint32 m_errorCount;
};
bool addTag(const QString &tag, QStringList &lines)
@ -591,8 +659,8 @@ bool LoadTHUMB(QImageIOHandler *handler, QImage &img)
return false;
}
#else
auto ba = device->readAll();
if (rawProcessor->open_buffer(ba.data(), ba.size()) != LIBRAW_SUCCESS) {
auto all = device->readAll();
if (rawProcessor->open_buffer(all.data(), all.size()) != LIBRAW_SUCCESS) {
return false;
}
#endif