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Date: Tue, 31 May 2011 22:41:41 +0200
From: Matthias Andree <matthias.andree@....de>
To: oss-security@...ts.openwall.com
Subject: Re: CVE request for fetchmail STARTTLS hang (Denial
of Service)
Am 31.05.2011 22:01, schrieb Josh Bressers:
>
>
> ----- Original Message -----
>> Could I get a CVE name for the issue in
>> <http://gitorious.org/fetchmail/fetchmail/blobs/legacy_63/fetchmail-SA-2011-01.txt>?
>>
>
> Please use CVE-2011-1947.
Thanks.
> I can't help but wonder what else could be vulnerable to a similar flaw.
> Has anyone looked?
I seriously considered not asking for a CVE in the first place because
it's rather close to a resource-hogging-through-slowdowns attack vector,
if you send at a very slow pace just avoiding the timeout by a notch,
you hog your peer's resources for extended amounts of time -- and I
can't think of good heuristics to tell abuse from legit use by those on
slow links apart, and it's pointless listing CVEs for the unfixable
situations.
Anecdotal story from the fix: I've been particularly disappointed that
Solaris 10 doesn't support setsockopt(n, SOL_SOCKET, SO_RCVTIMEO, &foo,
sizeof foo); (returns -1 with errno == EAFNOSUPPORT), which would have
been the thorough and easy way out. I've had the code in place and
released as candidate, but umm, no, didn't work. I do set SO_KEEPALIVE
now, but that's not anywhere close of defending against malice.
Rewriting the whole socket stuff as non-blocking code with
poll()/select() which is supposed to be the canonical portable way was
too intrusive, hence, a no-go for a stable release update.
Best regards
Matthias Andree
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