Date: Tue, 10 Nov 2015 11:42:31 +0100 From: Yves-Alexis Perez <corsac@...ian.org> To: kernel-hardening@...ts.openwall.com, Matthew Garrett <mjg59@...f.ucam.org> Cc: Theodore Tso <tytso@...gle.com>, Emese Revfy <re.emese@...il.com>, Kees Cook <keescook@...omium.org>, PaX Team <pageexec@...email.hu>, Brad Spengler <spender@...ecurity.net>, Greg KH <gregkh@...uxfoundation.org>, Josh Triplett <josh@...htriplett.org> Subject: Re: Re: Proposal for kernel self protection features On lun., 2015-11-09 at 21:13 +0000, Matthew Garrett wrote: > On Mon, Nov 09, 2015 at 09:09:22PM +0000, Jason Cooper wrote: > > > Well, That's why I referred to reading from /boot or from a flash > > partition. Existing bootloaders in the field already have that > > capability. That's how they load the kernel. > > This doesn't really handle cases like network booting. Most SoCs have > some kind of RNG, recent x86 has hardware RNG, older x86 frequently has > an RNG in a TPM. Pulling an entropy seed from the filesystem is a > reasonable fallback, but we should definitely be thinking of it as a > fallback - someone with physical access to your system while it's turned > off may be able to infer the ASLR state for your next boot, for > instance. About the TPM RNG: I was definitely interested in the “get entropy from TPM” kind of thing for my laptop (even though I think my laptop would not be the worst place to find entropy). Right now I'm using rng-tools to read from /dev/hwrng (handled by tpm_rng module), which then feeds entropy to /dev/random (or maybe directly using the RND ioctls). Do you think bypassing userland completely in order to be able to feed that entropy even before userland is completely initialized would be helpful? Regards, -- Yves-Alexis Download attachment "signature.asc" of type "application/pgp-signature" (474 bytes)
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.