On Tue, Feb 2, 2021 at 3:51 PM Ben Widawsky <ben.widawsky@xxxxxxxxx> wrote: > > On 21-02-01 13:28:48, Konrad Rzeszutek Wilk wrote: > > On Fri, Jan 29, 2021 at 04:24:37PM -0800, Ben Widawsky wrote: > > > The Get Log command returns the actual log entries that are advertised > > > via the Get Supported Logs command (0400h). CXL device logs are selected > > > by UUID which is part of the CXL spec. Because the driver tries to > > > sanitize what is sent to hardware, there becomes a need to restrict the > > > types of logs which can be accessed by userspace. For example, the > > > vendor specific log might only be consumable by proprietary, or offline > > > applications, and therefore a good candidate for userspace. > > > > > > The current driver infrastructure does allow basic validation for all > > > commands, but doesn't inspect any of the payload data. Along with Get > > > Log support comes new infrastructure to add a hook for payload > > > validation. This infrastructure is used to filter out the CEL UUID, > > > which the userspace driver doesn't have business knowing, and taints on > > > invalid UUIDs being sent to hardware. > > > > Perhaps a better option is to reject invalid UUIDs? > > > > And if you really really want to use invalid UUIDs then: > > > > 1) Make that code wrapped in CONFIG_CXL_DEBUG_THIS_IS_GOING_TO..? > > > > 2) Wrap it with lockdown code so that you can't do this at all > > when in LOCKDOWN_INTEGRITY or such? > > > > The commit message needs update btw as CEL is allowed in the latest rev of the > patches. > > We could potentially combine this with the now added (in a branch) CONFIG_RAW > config option. Indeed I think that makes sense. Dan, thoughts? Yeah, unknown UUIDs blocking is the same risk as raw commands as a vendor can trigger any behavior they want. A "CONFIG_RAW depends on !CONFIG_INTEGRITY" policy sounds reasonable as well.
