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From: Lowell Gilbert <freebsd-security-local@be-well.ilk.org>
To: mike tancsa <mike@sentex.net>
Cc: "freebsd-security\@freebsd.org" <freebsd-security@freebsd.org>
Subject: Re: TCP SACK (CVE-2019-5599)
References: <29d6e221-e88a-f828-0e5b-ac235691ed86@sentex.net>
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Date: Tue, 18 Jun 2019 10:48:13 -0400
In-Reply-To: <29d6e221-e88a-f828-0e5b-ac235691ed86@sentex.net> (mike tancsa's
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mike tancsa <mike@sentex.net> writes:

> *How does I know if this is enabled in my default kernel on RELENG_12 ?
> There is some vague mention in various forums this is not the default on
> FreeBSD ? Can anyone shed more light as to how this does/does not impact
> FreeBSD ?

If the net.inet.tcp.functions_default sysctl doesn't list "rack", you
don't have to worry about it. As far as I can see from a quick look at
my source tree, you would have to load a module to use it.