Date: Tue, 19 Jun 2012 14:44:35 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-security@freebsd.org Cc: bz@freebsd.org, "Simon L. B. Nielsen" <simon@freebsd.org>, Steven Chamberlain <steven@pyro.eu.org> Subject: Re: Update for FreeBSD Security Advisory FreeBSD-SA-12:04.sysret for 8.1 Message-ID: <201206191444.35285.jhb@freebsd.org> In-Reply-To: <4FE0C1DA.2080809@pyro.eu.org> References: <497105EC-3223-4E59-A6E6-F810A15BCA5C@FreeBSD.org> <4FE0C1DA.2080809@pyro.eu.org>
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On Tuesday, June 19, 2012 2:15:54 pm Steven Chamberlain wrote: > Hi, > > Thanks a lot of looking into this! > > On 18/06/12 22:37, Simon L. B. Nielsen wrote: > > Note that this is ONLY for FreeBSD 8.1. Other branches are OK. > > Having seen the correct fix now, I'm starting to wonder if the commit to > RELENG_7_4 was really okay too? > > http://svnweb.freebsd.org/base/releng/7.4/sys/amd64/amd64/trap.c?annotate=236953#l975 > > The inserted code does not appear at the end of the function, like it > does now in all other versions including 8.1 which is the most similar. > > I expect this would at least trap if the exploit was attempted, but then > it would omit the rest of the function, including userret(); would that > have consequences? It would perhaps be best to occur at the end of the function to be consistent. However, the fix is functionally correct in this case. -- John Baldwin
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