AIM file transfers to Pidgin are marked "Failed" in AOL Instant Messenger

[Evan Schoenberg]

On Aug 28, 2007, at 10:30 AM, Kyryll A Mirnenko aka Mirya wrote:

> Seems like I've found the problematic code.
> In libpurple/protocols/oscar/oft.c:
>
> static void peer_oft_send(...) {
> ...
> length = 192 + MAX(64, frame->name_length + 1);
> ...
> byte_stream_putraw(&bs, frame->name, MAX(64, frame->name_length + 1));
> ...
> }
>
> Looks like
> a) name_length is always >= 64, just 'cause of the way it's read  
> from the
> incoming packet
> b) if an actual filename length is <= 63 (so it fits 64 bytes with  
> terminating
> null), then setting length to 192 + 64 makes AIM6 AOL client mark the
> transfer as successful
> c) if the filename length is >= 64 than AIM6 makes it as "Failed"  
> whatever
> modifications to the original formula I tried (MAX(64, frame- 
> >name_length +
> 1) == frame->name_length + 1 there)
> d) Miranda IM OSCAR plugin (noted in the previous message) fails to  
> accept
> files with the filename longer than 64 at all
> e) sniffing AIM6 to AIM6 traffic shows that it uses some upgraded  
> version of
> file transfer exchange; the OftFrame has "OFT3" header and some  
> extra fields
> in the middle (adding extra 8 bytes); the frame size field seems to  
> stay
> where it was, and the filename is still the last bytes of the frame  
> with
> extra null byte added; with that AIM6 accepts all filenames correctly
> regardless of its size

As I commented in your other thread about AIM file transfers, a Pidgin  
Trac ticket with your findings would be great.  Sounds like you're on  
the road to a patch to fix this one -- be sure to attach it to the  
ticket so we can review it and get it into libpurple.  Definitely let  
us know if you run into any problems!

Cheers,
Evan