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Message-ID: <alpine.GSO.2.20.1711081305160.6849@scrappy.simplesystems.org>
Date: Wed, 8 Nov 2017 13:13:20 -0600 (CST)
From: Bob Friesenhahn <bfriesen@...ple.dallas.tx.us>
To: oss-security@...ts.openwall.com
cc: "Jonas 'Sortie' Termansen" <sortie@...si.org>
Subject: Re: Race condition between UDP bind(2) and connect(2)
delivers wrong datagrams
On Wed, 8 Nov 2017, Eric Blake wrote:
>>
>> This issue is not that case because Darwin[1], DragonFly[2], FreeBSD[3],
>> GNU/Hurd (though by importing Linux man pages), Linux[4], NetBSD[5], and
>> OpenBSD[6] all document behavior compatible with POSIX[7].
>
> It doesn't matter what the implementations document (if their
> documentation is copying from POSIX), but what they actually DO.
For the purpose of this list (about security) it seems to me that the
current behavior makes use of the recv(2) (or read(2)) system calls
inherently insecure since there is no way to verify that a received
message is from the expected source address. The only work-around is
to intentionally discard messages until no more messages are
available, but this may discard valid messages.
This makes most common uses of recv(2) insecure.
Bob
--
Bob Friesenhahn
bfriesen@...ple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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