From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Getz Subject: Re: IRQF_SAMPLE_RANDOM question... Date: Tue, 7 Apr 2009 07:16:25 -0400 Message-ID: <200904070716.25846.rgetz@blackfin.uclinux.org> References: <200904061430.26276.rgetz@blackfin.uclinux.org> <1239044483.14392.55.camel@calx> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Chris Peterson" To: "Matt Mackall" Return-path: In-Reply-To: <1239044483.14392.55.camel@calx> Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon 6 Apr 2009 15:01, Matt Mackall pondered: > On Mon, 2009-04-06 at 14:30 -0400, Robin Getz wrote: > > We have lots of embedded headless systems (no keyboard/mouse, no > > soundcard, no video) systems with *no* sources of entropy - and > > people using SSL. > > I'd rather add a random_sample_network call somewhere reasonably central > in the network stack. Then we can use the knowledge that the sample is > network-connected in the random core to decide how to measure its > entropy. The trouble with IRQF_SAMPLE_RANDOM is that many of its users > are technically bogus as entropy sources in the current model. OK - that makes more sense. Does that mean we also shouldn't be using IRQF_SAMPLE_RANDOM on interrupt sources in subsystems which already have add_xxx_randomness() in them? (block devices, and input devices?) block/blk-core.c -> blk_end_io() -> add_disk_randomness() drivers/input/input.c -> input_event() -> add_input_randomness() drivers/block/xen-blkfront.c, line 639 drivers/input/touchscreen/wm97xx-core.c, line 374 drivers/input/keyboard/gpio_keys.c, line 145 drivers/input/keyboard/bf54x-keys.c, line 255 drivers/input/serio/hp_sdc.c, line 881 > I'm eventually going to move the RNG away from the strict theoretical > entropy accounting model to a more pragmatic one which will be much > happier with iffy entropy sources, but that's a ways off. Looking forward to it.