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https://issues.apache.org/jira/browse/PDFBOX-5521?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17610436#comment-17610436
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Michael Klink commented on PDFBOX-5521:
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{quote}COSWriter code hits an "old" signature that is (for whatever reason,
maybe it was incorrectly included) present in the incremental part.{quote}
Most likely the problem signature in question is the usage rights signature.
(The message "This document enabled extended features in Adobe Acrobat Reader."
indicates that there is a usage rights signature in the PDF in question.)
In contrast to other signatures, a usage rights signature dictionary need not
be an indirect object, it may be a direct object in the *Perms* dictionary
which in turn may be a direct object in the catalog dictionary. Thus, such a
usage rights signature may occur again and again in each incremental update
touching the catalog.
In particular such a recurring usage rights signature is not _incorrectly
included_ and the PDFBox signing code must be able to recognize that its
signature dictionary is not the dictionary of the currently to sign signature
field.
> Signing tries to set byteRange of old signature
> -----------------------------------------------
>
> Key: PDFBOX-5521
> URL: https://issues.apache.org/jira/browse/PDFBOX-5521
> Project: PDFBox
> Issue Type: Bug
> Components: Signing
> Affects Versions: 2.0.27
> Reporter: Tilman Hausherr
> Assignee: Tilman Hausherr
> Priority: Major
> Fix For: 2.0.28, 3.0.0 PDFBox
>
>
> A long bug report on the users mailing lists leads to the finding that the
> COSWriter code hits an "old" signature that is (for whatever reason, maybe it
> was incorrectly included) present in the incremental part. The signing then
> fails because the byte range to be written is longer than the existing byte
> range.
> To avoid this, we improve signature detection by checking that the size
> indicated by byteRange is higher than the existing PDF size.
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