[PDFBOX-4131] Stack overflow in fields

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.8
• Fix Version/s: 2.0.9, 3.0.0 PDFBox
• Component/s: AcroForm
• Assignee: Unassigned
• Reporter: Maison
• Created: 27/Feb/18 11:19
• Updated: 02/Dec/18 17:08
• Resolved: 18/Apr/18 07:41

Description

Note: unfortunately I can not attach original file for confidentiality reasons

I have a pdf containing some fields :

 

/AcroForm 2 0 R

...

2 0 obj
<<
/DR 5 0 R
/Fields [ ...  15 0 R 16 0 R 17 0 R ...]
>>

and then for field object 17 :

17 0 obj
<<
/DA (/Helv 8 Tf 0 g)
/FT /Tx
/Ff 1
/Kids [17 0 R 88 0 R 89 0 R]
/MaxLen 0
/T (Nom)
>>

Here we see that this field is contained in its children list : this triggers a recursivity loop during parsing (or at least during method call getAcroForm() )

    at java.lang.StringBuilder.toString(StringBuilder.java:407)
    at org.apache.pdfbox.cos.PDFDocEncoding.toString(PDFDocEncoding.java:135)
    at org.apache.pdfbox.cos.COSString.getString(COSString.java:203)
    at org.apache.pdfbox.cos.COSDictionary.getString(COSDictionary.java:670)
    at org.apache.pdfbox.pdmodel.interactive.form.PDFieldFactory.createField(PDFieldFactory.java:64)
    at org.apache.pdfbox.pdmodel.interactive.form.PDField.fromDictionary(PDField.java:80)
    at org.apache.pdfbox.pdmodel.interactive.form.PDNonTerminalField.getChildren(PDNonTerminalField.java:139)
    at org.apache.pdfbox.pdmodel.interactive.form.PDFieldTree$FieldIterator.enqueueKids(PDFieldTree.java:99)
    at org.apache.pdfbox.pdmodel.interactive.form.PDFieldTree$FieldIterator.enqueueKids(PDFieldTree.java:102)

...

 

I use pdfbox 2.0.8

Similar problem with preflight parser.

In this case a simple fix would be to ignore children fields that are the same as their parent ; however the references loop may be much more complicated.