[tor-relays] Log warning : possible (zlib) compression bomb on middle relays

[Sven Schmeling]

Hello,

same here on my middle relay running 0.4.4.5:

...
Nov 02 05:20:48.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:20:48.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:20:48.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:21:49.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:21:49.000 [warn] Possible zlib bomb; abandoning stream.
Nov 02 05:22:48.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:22:49.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:22:49.000 [warn] Possible zlib bomb; abandoning stream.
Nov 02 05:23:49.000 [warn] Possible zlib bomb; abandoning stream.
Nov 02 05:23:49.000 [warn] Possible zlib bomb; abandoning stream.
Nov 02 05:23:49.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:23:49.000 [warn] Possible compression bomb; abandoning stream.
Nov 02 05:23:49.000 [warn] Possible compression bomb; abandoning stream.
....

Regards

Am 02.11.20 um 11:05 schrieb Guinness:
> Hi all,
> 
> We are at least 3 users running middle relays from 0.4.4.5 and after having
> some logs like those :
> ```
> Nov 02 05:30:55.000 [warn] Possible compression bomb; abandoning stream.
> Nov 02 05:30:55.000 [warn] Possible zlib bomb; abandoning stream.
> Nov 02 05:30:56.000 [warn] Possible compression bomb; abandoning stream.
> Nov 02 05:31:00.000 [warn] Possible compression bomb; abandoning stream.
> Nov 02 05:31:00.000 [warn] Possible compression bomb; abandoning stream.
> Nov 02 05:31:00.000 [warn] Possible compression bomb; abandoning stream.
> Nov 02 05:31:55.000 [warn] Possible compression bomb; abandoning stream.
> Nov 02 05:31:56.000 [warn] Possible compression bomb; abandoning stream.
> ```
> 
> I'm wondering if this is an attack or a new feature (haven't checked
> yet) but I'd like to know how many users are impacted.
> 
> The interesting informations are :
>   * Number of warnings
>   * What kind of relay it is (middle, exit, entry)
> 
> After your answers, I'll complete the issue I have opened on the bug
> tracker.
> 
> 
> Cheers,
> 
> 
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