Date: Tue, 15 Nov 2011 11:14:08 +0400 From: Andrey Chernov <ache@FreeBSD.ORG> To: David Schultz <das@FreeBSD.ORG> Cc: svn-src-head@FreeBSD.ORG, svn-src-all@FreeBSD.ORG, src-committers@FreeBSD.ORG Subject: Re: svn commit: r227520 - head/lib/libc/gen Message-ID: <20111115071407.GB86944@vniz.net> In-Reply-To: <201111150549.pAF5nOu8083029@svn.freebsd.org> References: <201111150549.pAF5nOu8083029@svn.freebsd.org>
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On Tue, Nov 15, 2011 at 05:49:24AM +0000, David Schultz wrote: > Author: das > Date: Tue Nov 15 05:49:24 2011 > New Revision: 227520 > URL: http://svn.freebsd.org/changeset/base/227520 > > Log: > Further reduce diffs with OpenBSD's arc4random. The main functional > change here is to ensure that when a process forks after arc4random > is seeded, the parent and child don't observe the same random sequence. > OpenBSD's fix introduces some additional overhead in the form of a > getpid() call. This could be improved upon, e.g., by setting a flag > in fork(), if it proves to be a problem. > > This was discussed with secteam (simon, csjp, rwatson) in 2008, shortly > prior to my going out of town and forgetting all about it. The conclusion > was that the problem with forks is worrisome, but it doesn't appear to > have introduced an actual vulnerability for any known programs. > > The only significant remaining difference between our arc4random and > OpenBSD's is in how we seed the generator in arc4_stir(). Thanx for taking that! -- http://ache.vniz.net/
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