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Prevent StackOverflow in ParseTrailer and fix #1122 #1127

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Merged
BobLd merged 1 commit into from
Aug 9, 2025
Merged

Prevent StackOverflow in ParseTrailer and fix #1122 #1127

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9 changes: 9 additions & 0 deletions src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,15 @@

public class GithubIssuesTests
{
[Fact]
public void Issue1122()
{
var path = IntegrationHelpers.GetSpecificTestDocumentPath("StackOverflow_Issue_1122.pdf");

var ex = Assert.Throws<PdfDocumentFormatException>(() => PdfDocument.Open(path, new ParsingOptions() { UseLenientParsing = true }));
Assert.StartsWith("Reached maximum search depth while getting indirect reference.", ex.Message);
}

[Fact]
public void Issue1096()
{
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Binary file added src/UglyToad.PdfPig.Tests/Integration/SpecificTestDocuments/StackOverflow_Issue_1122.pdf
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25 changes: 20 additions & 5 deletions src/UglyToad.PdfPig/Tokenization/Scanner/PdfTokenScanner.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -625,7 +625,8 @@ private DictionaryToken GetStreamDictionary()
{
if (offset < 0)
{
var result = GetObjectFromStream(lengthReference.Data, offset);
ushort searchDepth = 0;
var result = GetObjectFromStream(lengthReference.Data, offset, ref searchDepth);

if (!(result.Data is NumericToken streamLengthToken))
{
Expand Down Expand Up @@ -714,9 +715,23 @@ public void DeregisterCustomTokenizer(ITokenizer tokenizer)

coreTokenScanner.DeregisterCustomTokenizer(tokenizer);
}

public ObjectToken? Get(IndirectReference reference)
{
ushort searchDepth = 0;
return Get(reference, ref searchDepth);
}

private ObjectToken? Get(IndirectReference reference, ref ushort searchDepth)
{
if (searchDepth > 1_000)
{
throw new PdfDocumentFormatException("Reached maximum search depth while getting indirect reference.");
}

searchDepth++;


if (isDisposed)
{
throw new ObjectDisposedException(nameof(PdfTokenScanner));
Expand All @@ -740,7 +755,7 @@ public void DeregisterCustomTokenizer(ITokenizer tokenizer)
// Negative offsets refer to a stream with that number.
if (offset < 0)
{
var result = GetObjectFromStream(reference, offset);
var result = GetObjectFromStream(reference, offset, ref searchDepth);

return result;
}
Expand Down Expand Up @@ -802,11 +817,11 @@ private ObjectToken BruteForceFileToFindReference(IndirectReference reference)
}
}

private ObjectToken GetObjectFromStream(IndirectReference reference, long offset)
private ObjectToken GetObjectFromStream(IndirectReference reference, long offset, ref ushort searchDepth)
{
var streamObjectNumber = offset * -1;

var streamObject = Get(new IndirectReference(streamObjectNumber, 0));
var streamObject = Get(new IndirectReference(streamObjectNumber, 0), ref searchDepth);

if (!(streamObject?.Data is StreamToken stream))
{
Expand Down
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