Fix #1601: guard against corrupt object-stream references in xref streams - #1602
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Fix #1601: guard against corrupt object-stream references in xref streams#1602andreasrosdalw wants to merge 1 commit into
andreasrosdalw wants to merge 1 commit into
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…xref streams A cross-reference stream's type 2 (compressed object) entry can reference an object-stream number that does not correspond to any parsed object (e.g. a corrupt/malformed xref stream where the reference is far outside the actual object range). PdfReader.readDocObj() looked up that object number via xrefObj.get(n) without any bounds or type check, so a malformed PDF could crash the reader with a raw IndexOutOfBoundsException (or ClassCastException) instead of a handled parse error. Skip such entries the same way getPdfObject(int) already tolerates out-of-range indices, so a single corrupt compressed-object reference no longer prevents the rest of an otherwise valid document from parsing.
Up to standards ✅🟢 Issues
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| Metric | Results |
|---|---|
| Complexity | 14 |
| Duplication | 0 |
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Summary
PdfReadercould throw a rawIndexOutOfBoundsException("Index 57407 out of bounds for length 899") when parsing a PDF whose cross-reference stream has a type 2 (compressed object) entry pointing at an object-stream number outside the document's actual object range.PdfReader.readDocObj(), theobjStmMarkprocessing loop callsxrefObj.get(n)with no bounds or type check, unlikegetPdfObject(int)a few hundred lines above, which already guardsidx < 0 || idx >= xrefObj.size(). A corrupt/malformed xref stream can set that object-stream number to an arbitrary value (e.g. via a truncated or hand-edited PDF), and the unguarded.get(n)throws instead of failing gracefully.objStmMarkentry when its key is out of range or does not actually resolve to aPRStream, mirroring the existing tolerant behavior ofgetPdfObject(int). A single corrupt compressed-object reference no longer prevents the rest of an otherwise valid document from parsing.