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Add depth check

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This commit is contained in:
theolivenbaum
2022-03-28 20:57:51 +02:00
committed by GitHub
parent abcbdc55e3
commit c14238676c
1 changed files with 14 additions and 3 deletions
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17
src/UglyToad.PdfPig/Parser/CatalogFactory.cs
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@@ -10,6 +10,11 @@
internal static class CatalogFactory internal static class CatalogFactory
{ {
// Keep the algorithm below from throwing a StackOverflow exception.
// It probably should be refactored to not be recursive
private const ushort MAX_TREE_DEPTH = 1024;
public static Catalog Create(IndirectReference rootReference, DictionaryToken dictionary, public static Catalog Create(IndirectReference rootReference, DictionaryToken dictionary,
IPdfTokenScanner scanner, IPdfTokenScanner scanner,
bool isLenientParsing) bool isLenientParsing)
@@ -49,7 +54,7 @@
var pageNumber = 0; var pageNumber = 0;
var pageTree = ProcessPagesNode(pagesReference, pages, new IndirectReference(1, 0), true, var pageTree = ProcessPagesNode(pagesReference, pages, new IndirectReference(1, 0), true,
scanner, isLenientParsing, ref pageNumber); scanner, isLenientParsing, ref pageNumber, 0);
return new Catalog(dictionary, pages, pageTree); return new Catalog(dictionary, pages, pageTree);
} }
@@ -59,8 +64,14 @@
bool isRoot, bool isRoot,
IPdfTokenScanner pdfTokenScanner, IPdfTokenScanner pdfTokenScanner,
bool isLenientParsing, bool isLenientParsing,
ref int pageNumber) ref int pageNumber,
ushort depth)
{ {
if(depth > MAX_TREE_DEPTH)
{
throw new PdfDocumentFormatException($"Tree exceeded maximum depth of {MAX_TREE_DEPTH}, aborting.");
}
var isPage = false; var isPage = false;
if (!nodeDictionary.TryGet(NameToken.Type, pdfTokenScanner, out NameToken type)) if (!nodeDictionary.TryGet(NameToken.Type, pdfTokenScanner, out NameToken type))
@@ -133,7 +144,7 @@
throw new PdfDocumentFormatException($"Could not find dictionary associated with reference in pages kids array: {kidRef}."); throw new PdfDocumentFormatException($"Could not find dictionary associated with reference in pages kids array: {kidRef}.");
} }
var kidNode = ProcessPagesNode(kidRef.Data, kidDictionaryToken, reference, false, pdfTokenScanner, isLenientParsing, ref pageNumber); var kidNode = ProcessPagesNode(kidRef.Data, kidDictionaryToken, reference, false, pdfTokenScanner, isLenientParsing, ref pageNumber, depth + 1);
nodeChildren.Add(kidNode); nodeChildren.Add(kidNode);
} }