# Exploit Title: Oracle Java lookupByteBI function heap buffer overflow
# Google Dork:
# Date: 2013-09-03
# Exploit Author: GuHe
# Vendor Homepage: http://www.oracle.com/
# Software Link:
http://www.oracle.com/technetwork/java/javase/downloads/index.html
# Version: 7u21 and eariler
# Tested on: Windows 7
# CVE : CVE-2013-2470

PoC: https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/28050.zip


CVE-2013-2470 - Java_sun_awt_image_ImagingLib_lookupByteBI heap buffer
overflow


1. Affected Software
JRE 7 update 21 and earlier
JRE 6 update 45 and earlier


2. Root cause analysis

The "Java_sun_awt_image_ImagingLib_lookupByteBI" performs byte lookup
operation on two BufferedImage.

In the following code:

 /* Mlib needs 16bit lookuptable and must be signed! */
    if (src->type == MLIB_SHORT) {
        unsigned short *sdataP = (unsigned short *) src->data;
        unsigned short *sP;
        if (dst->type == MLIB_BYTE) {
            unsigned char *cdataP  = (unsigned char *)  dst->data;
            unsigned char *cP;
            if (nbands > 1) {
                retStatus = 0;
            }
            else {
                int x, y;
                for (y=0; y < src->height; y++) {
                    cP = cdataP;
                    sP = sdataP;
                    for (x=0; x < src->width; x++) {
                        *cP++ = table[0][*sP++];
                    }

                    /*
                     * 4554571: increment pointers using the scanline stride
                     * in pixel units (not byte units)
                     */
                    cdataP += dstImageP->raster.scanlineStride;
                    sdataP += srcImageP->raster.scanlineStride;
                }
            }
        }
        /* How about ddata == null? */
    }

It tries to map data in src raster to the dst raster. The total bytes
written to dst rater buffer is:
(src->width) * (src->height). However, it does not correctly check the size
of the dst buffer, if the size of the
dst buffer is smaller than (src->width) * (src->height), it will be
overflowed.


3. Poc
See "TestByteBI.java" for the source code.
And you can test the poc by directly open the "HelloApplet.html" in a web
browser.


4. Tested on
JRE 7 update 21 on Windows 7 Enterprise