Peter Wyatt created PDFBOX-5156:
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Summary: Error in identification of PDF comment symbol % as a
token separator with PDF names
Key: PDFBOX-5156
URL: https://issues.apache.org/jira/browse/PDFBOX-5156
Project: PDFBox
Issue Type: Bug
Components: Parsing
Affects Versions: 3.0.0 PDFBox
Reporter: Peter Wyatt
The DARPA-funded SafeDocs research program has developed a Compacted PDF Syntax
text case to stress-test PDF lexical analyzers/parsers. See
[https://github.com/pdf-association/safedocs/tree/main/CompactedSyntax]. The
output of this test PDF was examined in detail using the PDFBOX debugger "view
internal structure" feature for both the body and content stream and this is
the only error... so well done!
PDFBOX 3.0.0-RC1 was tested using this highly targeted test PDF and there is an
error in the lexical analysis (token separators) between PDF name objects and
PDF comments. As specified in ISO 32000-2:
* clause 7.2.3: "The delimiter characters (, ), <, >, [, ], /, and % are
special (LEFT PARENTHESIS (28h), RIGHT PARENTHESIS (29h), LESS-THAN SIGN (3Ch),
GREATER-THAN SIGN (3Eh), LEFT SQUARE BRACKET (5Bh), RIGHT SQUARE BRACKET (5Dh),
SOLIDUS (2Fh) and PERCENT SIGN (25h), respectively). They delimit syntactic
entities such as arrays, names, and comments. ... Any of these delimiters
terminates the entity preceding it and is not included in the entity."
* clause 7.2.4 "Any occurrence of the PERCENT SIGN (25h) outside a string or
inside a content stream (see 7.8.2, "Content streams") introduces a comment."
Offset 3561 (as reported in the output below) is in the middle of this fragment
of PDF: {{<</Root 1 0 R/Info%comment after name}}
Note also that other/earlier versions of PDFBOX were not tested.
{{java -jar pdfbox-app-3.0.0-RC1.jar debug
safedocs\CompactedSyntax\CompactedPDFSyntaxTest.pdf}}
{{Apr. 08, 2021 9:41:24 AM org.apache.pdfbox.pdfparser.BaseParser
parseDirObject}}
{{WARNING: Skipped unexpected dir object = 'after' at offset 3561}}
{{Apr. 08, 2021 9:41:24 AM org.apache.pdfbox.pdfparser.BaseParser
parseCOSDictionaryNameValuePair}}
{{WARNING: Bad dictionary declaration at offset 3562}}
{{Apr. 08, 2021 9:41:24 AM org.apache.pdfbox.pdfparser.BaseParser
parseCOSDictionary}}
{{WARNING: Invalid dictionary, found: 'n' but expected: '/' at offset 3562}}
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