Author: toad
Date: 2008-02-15 14:04:17 +0000 (Fri, 15 Feb 2008)
New Revision: 17937
Modified:
trunk/freenet/src/freenet/clients/http/filter/JPEGFilter.java
Log:
Support a much wider range of JPEG markers. Fixes two images I was sent.
A site on the web had told me that you only need to support a few markers,
unfortunately this wasn't true, JPEG is very complex and the full spec is not
available without payment.
Modified: trunk/freenet/src/freenet/clients/http/filter/JPEGFilter.java
===================================================================
--- trunk/freenet/src/freenet/clients/http/filter/JPEGFilter.java
2008-02-15 13:47:40 UTC (rev 17936)
+++ trunk/freenet/src/freenet/clients/http/filter/JPEGFilter.java
2008-02-15 14:04:17 UTC (rev 17937)
@@ -268,13 +268,56 @@
finished = true;
if(logMINOR)
Logger.minor(this, "End of
image");
- } else
- // Essential but unparsed frames
- if(markerType == 0xDB // quantisation
table
- || markerType == 0xDD //
restart interoperability marker
- || markerType == 0xC4 //
huffman table
- || markerType == 0xC0) { //
start of frame
- // Essential, non-terminal frames.
+ } else {
+ boolean valid = false;
+ // We used to support only DB C4 C0,
because some website said they were
+ // sufficient for decoding a JPEG.
Unfortunately they are not, JPEG is a
+ // very complex standard and the full
spec is only available for a fee.
+ // FIXME somebody who has access to the
spec should have a look at this,
+ // and ideally write some chunk
sanitizers.
+ switch(markerType) {
+ // descriptions from
http://svn.xiph.org/experimental/giles/jpegdump.c (GPL)
+ case 0xc0: // start of frame
+ case 0xc1: // extended sequential,
huffman
+ case 0xc2: // progressive, huffman
+ case 0xc3: // lossless, huffman
+ case 0xc5: // differential sequential,
huffman
+ case 0xc6: // differential progressive,
huffman
+ case 0xc7: // differential lossless,
huffman
+ // DELETE 0xc8 - "reserved for
JPEG extension" - likely to be used for Bad Things
+ case 0xc9: // extended sequential,
arithmetic
+ case 0xca: // progressive, arithmetic
+ case 0xcb: // lossless, arithmetic
+ case 0xcd: // differential sequential,
arithmetic
+ case 0xcf: // differential lossless,
arithmetic
+ case 0xc4: // define huffman tables
+ case 0xcc: // define arithmetic-coding
conditioning
+ // Restart markers
+ case 0xd0:
+ case 0xd1:
+ case 0xd2:
+ case 0xd3:
+ case 0xd4:
+ case 0xd5:
+ case 0xd6:
+ case 0xd7:
+ // Delimiters:
+ case 0xd8: // start of image
+ case 0xd9: // end of image
+ case 0xda: // start of scan
+ case 0xdb: // define quantization tables
+ case 0xdc: // define number of lines
+ case 0xdd: // define restart interval
+ case 0xde: // define hierarchical
progression
+ case 0xdf: // expand reference
components
+ // DELETE APP0 - APP15 -
application data sections, likely to be troublesome.
+ // DELETE extension data
sections JPG0-6,SOF48,LSE,JPG9-JPG13, JCOM (comment!!), TEM ("temporary private
use for arithmetic coding")
+ // DELETE 0x02 - 0xbf reserved
sections.
+ // Do not support JPEG2000 at
the moment. Probably has different headers. FIXME.
+ valid = true;
+ }
+ if(valid) {
+ // Essential, non-terminal, but
unparsed frames.
if(blockLength < 2)
throwError("Invalid frame
length", "The file includes an invalid frame (length "+blockLength+").");
if(dos != null) {
@@ -297,6 +340,7 @@
skipBytes(dis, blockLength - 2);
continue;
}
+ }
if(cis.count() != countAtStart + blockLength)
throwError("Invalid frame", "The length
of the frame is incorrect (read "+
