[jcifs] RE: Corrupted MP3/JPEGS

[Allen, Michael B (RSCH)]

This is what the "edit distance" (a byte level binary diff) looks like:

MAT: pos1=0 pos2=0 len=4096
INS: pos2=4096        len=190
MAT: pos1=4096 pos2=4286 len=4286
DEL: pos1=8382        len=66
MAT: pos1=8449 pos2=8573 len=4285
DEL: pos1=12734        len=66
MAT: pos1=12800 pos2=12858 len=4096
INS: pos2=16954        len=190
MAT: pos1=16896 pos2=17144 len=4286
DEL: pos1=21182        len=66
MAT: pos1=21248 pos2=21430 len=4285
DEL: pos1=25533        len=47
MAT: pos1=25580 pos2=25715 len=1
DEL: pos1=25581        len=19
MAT: pos1=25600 pos2=25716 len=1296
INS: pos2=27012        len=132
more of the same...

So good matches bad for 4096 bytes, then good needs to insert 190 bytes
to match bad, then they match again for 4286 bytes ...etc. In total the
corrupted files are slightly larger. The INS and DEL fragments are other
snipplets from the file itself. Looks like plain and simple buffer corruption. I
don't know where the 4096 is coming from though. The negotiated buf size
could be 4096 but it's rarely a perfect power of 2 like that. The
TransactNamedPipeInputStream default buffer size is 4096 but I don't think
you're using a named pipe to transfer files so....

It would help emmensely if you could reproduce this.

> -----Original Message-----
> From:	Sujit Jagdev [SMTP:sujit.jagdev at casero.com]
> Sent:	Monday, December 02, 2002 12:55 PM
> To:	Allen at casero.com; Michael B +AFw-(RSCH+AFw-); jcifs at lists.samba.org
> Subject:	RE: Corrupted MP3/JPEGS
> 
> 
> Michael,
> Here are the files that you requested.
> Thanks
> Sujit
> 
> 
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> 
> The information contained in this message is proprietary of Casero Inc.,
> protected from disclosure, and may be privileged. The information is
> intended to be conveyed only to the designated recipient(s) of the
> message. If the reader of this message is not the intended recipient,
> you are hereby notified that any dissemination, use, distribution or
> copying of this communication is strictly prohibited and may be
> unlawful. If you have received this communication in error, please
> notify us immediately by replying to the message and deleting it from
> your computer. Thank you. << File: corrupted_Water lilies.jpg >>  << File: good_Water lilies.jpg >>  << File: good_Winter.jpg >>  << File: corrupted_Winter.jpg >>