Document.save() owner_pw & user_pw has buffer overflow bug.

[lys0829]

Please provide all mandatory information!

Describe the bug (mandatory)

owner_pw & user_pw arguments in Document.save()has buffer overflow bug. May cause program crash and arbitrary code execution.

To Reproduce (mandatory)

PoC:

import fitz

pdf = fitz.Document()
pdf.new_page()
pdf.save(1, owner_pw="a"*1000)

Your configuration (mandatory)

FROM ubuntu:20.04
MAINTAINER Lys

RUN apt-get update && \
    DEBIAN_FRONTEND=noninteractive apt-get install -yq python3.8=3.8.10-0ubuntu1~20.04.5 python3-pip

RUN pip3 install PyMuPDF==1.20.2

[JorjMcKie]

Thanks for the report.
There exists a limitation to 40 characters. We will document this and include a respective check.

[julian-smith-artifex-com]

Fixed in PyMuPDF-1.21.1.