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Try to re-sync Ogg parser when invalid bytes are detected

This commit is contained in:
Martchus 2021-08-14 13:41:40 +02:00
parent c9f6ae77e2
commit dd2b75d845
1 changed files with 17 additions and 4 deletions
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21
ogg/oggcontainer.cpp
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@ -188,12 +188,13 @@ void OggContainer::internalParseHeader(Diagnostics &diag, AbortableProgressFeedb
CPP_UTILITIES_UNUSED(progress)
static const string context("parsing OGG bitstream header");
bool pagesSkipped = false;
bool pagesSkipped = false, continueFromHere = false;
// iterate through pages using OggIterator helper class
try {
// ensure iterator is setup properly
for (m_iterator.removeFilter(), m_iterator.reset(); m_iterator; m_iterator.nextPage()) {
for (m_iterator.removeFilter(), m_iterator.reset(); m_iterator;
continueFromHere ? [&] { continueFromHere = false; }() : m_iterator.nextPage()) {
const OggPage &page = m_iterator.currentPage();
if (m_validateChecksums && page.checksum() != OggPage::computeChecksum(stream(), page.startOffset())) {
diag.emplace_back(DiagLevel::Warning,
@ -248,8 +249,20 @@ void OggContainer::internalParseHeader(Diagnostics &diag, AbortableProgressFeedb
diag.emplace_back(DiagLevel::Critical, "The OGG file is truncated.", context);
} catch (const InvalidDataException &) {
// thrown when first 4 byte do not match capture pattern
diag.emplace_back(
DiagLevel::Critical, argsToString("Capture pattern \"OggS\" at ", m_iterator.currentSegmentOffset(), " expected."), context);
const auto expectedOffset = m_iterator.currentSegmentOffset();
diag.emplace_back(DiagLevel::Critical, argsToString("Capture pattern \"OggS\" at ", expectedOffset, " expected."), context);
if (m_iterator.resyncAt(expectedOffset)) {
diag.emplace_back(DiagLevel::Warning,
argsToString("Found next capture pattern \"OggS\" at ", m_iterator.currentPageOffset(), ". Skipped ",
m_iterator.currentPageOffset() - expectedOffset, " invalid bytes."),
context);
continueFromHere = true;
} else {
diag.emplace_back(DiagLevel::Critical,
argsToString(
"Aborting after not being able to find any \"OggS\" capture patterns within 65307 bytes (from offset ", expectedOffset, ")."),
context);
}
}
// invalidate stream sizes in case pages have been skipped