Date: Fri, 14 Sep 2012 17:29:37 +0100 From: Ben Laurie <benl@freebsd.org> To: Mark Murray <markm@freebsd.org> Cc: Arthur Mesh <arthurmesh@gmail.com>, Ian Lepore <freebsd@damnhippie.dyndns.org>, Doug Barton <dougb@freebsd.org>, freebsd-security@freebsd.org, RW <rwmaillists@googlemail.com>, "Bjoern A. Zeeb" <bz@freebsd.org> Subject: Re: svn commit: r239569 - head/etc/rc.d Message-ID: <CAG5KPzwOdCkybj3D5uic1KC-pwW-pewgsrqrXg60f5SJjtzYPw@mail.gmail.com> In-Reply-To: <E1TCXN0-000NFT-7I@groundzero.grondar.org> References: <50453686.9090100@FreeBSD.org> <20120911082309.GD72584@dragon.NUXI.org> <504F0687.7020309@FreeBSD.org> <201209121628.18088.jhb@freebsd.org> <5050F477.8060409@FreeBSD.org> <20120912213141.GI14077@x96.org> <20120913052431.GA15052@dragon.NUXI.org> <alpine.BSF.2.00.1209131258210.13080@ai.fobar.qr> <alpine.BSF.2.00.1209141336170.13080@ai.fobar.qr> <E1TCXN0-000NFT-7I@groundzero.grondar.org>
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On Fri, Sep 14, 2012 at 3:59 PM, Mark Murray <markm@freebsd.org> wrote: >> 5) send all data to the kernel but XORing the data together on >> overflow in the kernel (can control when buffer full and only then >> take action when needed, indepedent on how seed data is chosen, >> withdrawn) > > I've already coded this up :-) (well, similar). This is the "improved > file handling" that I was thinking of. Note that I only do it for writes > to /d/r, and not for all entropy harvesting. It still largely kills the > entropy swamping, and while an attacker can subvert this, the attack > would be obvious. > > I'll send patches (untested) in a couple of hours for discussion. I used to like this idea, but it can break pretty badly if you repeat input, so in the end I decided hashes were the only safe way. > >> 6) send all data to the kernel but XORing the data + counter value >> together on overflow in the kernel (can control when buffer full and >> only then take action when needed, indepedent on how seed data is >> chosen, but why XOR?) > > Variation on above. > >> 7) send all data to the kernel and hash (arch dependent?) it + counter >> value into the buffer on overflow, as in b[n] = H(b[n] + c + i[n]) in >> the kernel (can control when buffer full and only then take action >> when needed, indepedent on how seed data is chosen, uses standard >> technology) > > Variation on above. > > M > -- > Mark R V Murray > Pi: 132511160 > > _______________________________________________ > freebsd-security@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-security > To unsubscribe, send any mail to "freebsd-security-unsubscribe@freebsd.org"
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