Crash in Add Magnet Link

[henryhog]

When you add a magnet torrent with a large number of characters in the tracker URL transmission will crash.

It does not seem to be exploitable, however it prevents the user from opening transmission as it will crash upon launch so it will cause Denial of Service. It occurs because it returns null on the DNS lookup I believe.

NORMAL MAGNET magnet:?xt=urn:btih:804cfd9a77cbc88108d387b18748d4d46af85b6e&dn=BackTrack+5+R3+Gnome+32bit&tr=udp%3A%2F%2Ftracker.openbittorrent.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80&tr=udp%3A%2F%2Fopen.demonii.com%3A1337

CRASH MAGNET magnet:?xt=urn:btih:804cfd9a77cbc88108d387b18748d4d46af85b6e&dn=BackTrack+5+R3+Gnome+32bit&tr=udp%3A%2F%2Ftracker.openbittorrent.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80&tr=udp%3A%2F%2Fopen.demAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAonii.com%3A1337

Tested on OSX and Ubuntu

[cfpp2p]

The only way to restart transmission after is to delete the offending magnet link from the torrents directory before restarting.

Attached is .torrent file created from above magnet crasher.

[cfpp2p]

By opening/adding with web client or rpc the torrent file I attached will crash transmission and there again you can't restart transmission until you delete it from the torrents directory.

[cfpp2p]

this is a duplicate of #5426