REDHAT-BUG-526911: Buffer Overflow

Adam Zabrocki reported flaws in xpdf's Splash::drawImage function related to buffer memory allocations:

2220 // allocate pixel buffers 2221 colorBuf = (SplashColorPtr)gmalloc((yp + 1) w nComps); 2222 if (srcAlpha) { 2223 alphaBuf = (Guchar )gmalloc((yp + 1) w); 2224 } else { 2225 alphaBuf = NULL; 2226 }

Values used to compute argument passed to gmalloc come from input PDF file. Properly chosen values will cause gmalloc to return NULL or buffer of insufficient size, leading to NULL pointer dereference or heap buffer overflow later.

Affected Splash output device is not available in xpdf 2.x versions and earlier. It is also not used in xpdf embedded in CUPS or tetex.

This was already fixed in poppler as part of preventive gmalloc -> gmallocn changes: http://cgit.freedesktop.org/poppler/poppler/commit/?id=9cf2325fb2

This fix is also present in the EL5 poppler packages.

Acknowledgements:

Red Hat would like to thank Adam Zabrocki for reporting this issue.