Xpdf, GPdf: Stack overflow in Decrypt::makeFileKey2

Background

Xpdf is an open source viewer for Portable Document Format (PDF) files. GPdf is a Gnome-based PDF viewer that includes some Xpdf code.

Description

iDEFENSE reports that the Decrypt::makeFileKey2 function in Xpdf’s Decrypt.cc insufficiently checks boundaries when processing /Encrypt /Length tags in PDF files.

Impact

An attacker could entice an user to open a specially-crafted PDF file which would trigger a stack overflow, potentially resulting in execution of arbitrary code with the rights of the user running Xpdf or GPdf.

Workaround

There is no known workaround at this time.

Resolution

All Xpdf users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-text/xpdf-3.00-r8"

All GPdf users should also upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-text/gpdf-2.8.2"