| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Wed, 6 Jun 2012 18:42:02 +0100 From: Matthew Garrett <mjg59@...f.ucam.org> To: Khalid Aziz <khalid.aziz@...com> Cc: linux-kernel@...r.kernel.org, bhelgaas@...gle.com, linux-pci@...r.kernel.org Subject: Re: [PATCH] Disable Bus Master on PCI device shutdown On Wed, Jun 06, 2012 at 11:32:36AM -0600, Khalid Aziz wrote: > Do we agree that if device shutdown routine cleanly shuts down all I/O, > clearing PCI Bus Mster bit should be safe? In the absence of hardware that dislikes the bus master bit ever being disabled, yes. Do we know if hardware is ever tested in that situation? > If yes, then we only have to deal with broken devices. So the approach > could be to disable Bus Master bit unless the device ID matches a > blacklist which we update as we find broken devices. I really don't > like the idea of maintaining blacklists in the kernel for such things > but is that a more practical approach? If blacklist does not sound > good, maybe we can ask drivers to tell PCI subsystem if they are not > ok with clearing Bus Master bit and then PCI subsystem could skip > those devices. Or we could just put responsibility on the drivers to ensure that the hardware won't continue doing any DMA, either by shutting down the engines or clearing the bit. -- Matthew Garrett | mjg59@...f.ucam.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists