tree 6bc0705812d06cf2626d945a558a45c580e45b5a
parent 09b39bf806be38caab78da7e721589670a6e7516
author Lei Zhang <thestig@chromium.org> 1674692873 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> 1674692873 +0000

Check the first page xref size when parsing linearized PDFs.

When parsing linearized PDFs, the first page's cross-reference table
objects may not match up with the trailer's size entry. The current
behavior for handling PDFs with this error is to trust the trailer's
size entry, but that leads to incorrect PDF parsing, whereas other PDF
readers handle this error correctly.

Fix this issue by changing CPDF_Parser::StartLinearizedParse() to check
for the error. In which case, rebuild the cross-reference table.

To test this, add a deliberately bad bug_1287409.pdf. The steps to
create this PDF is as follows:

1) Run: qpdf --linearize rectangles.pdf bug_1287409.pdf
2) Deliberately change the trailer's /Size entry in a text editor.

The existing CPDF_Parser behavior results in an unknown /MediaBox for
the first page, and the page size will default to 612x792. With this
fix, the page size will be correctly set to 200x300.

Bug: chromium:1287409
Change-Id: I4f31a1775521ec43b02fb4bf88c75fe09f087815
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/103473
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: K. Moon <kmoon@chromium.org>