On Wed, May 13, 2020 at 05:20:14PM -0400, Mimi Zohar wrote: > On Wed, 2020-05-13 at 12:41 -0700, Scott Branden wrote: > > > > On 2020-05-13 12:39 p.m., Mimi Zohar wrote: > > > On Wed, 2020-05-13 at 12:18 -0700, Scott Branden wrote: > > >> On 2020-05-13 12:03 p.m., Mimi Zohar wrote: > > >>> On Wed, 2020-05-13 at 11:53 -0700, Scott Branden wrote: > > >> Even if the kernel successfully verified the firmware file signature it > > >> would just be wasting its time. The kernel in these use cases is not always > > >> trusted. The device needs to authenticate the firmware image itself. > > > There are also environments where the kernel is trusted and limits the > > > firmware being provided to the device to one which they signed. > > > > > >>> The device firmware is being downloaded piecemeal from somewhere and > > >>> won't be measured? > > >> It doesn't need to be measured for current driver needs. > > > Sure the device doesn't need the kernel measuring the firmware, but > > > hardened environments do measure firmware. > > > > > >> If someone has such need the infrastructure could be added to the kernel > > >> at a later date. Existing functionality is not broken in any way by > > >> this patch series. > > > Wow! You're saying that your patch set takes precedence over the > > > existing expectations and can break them. > > Huh? I said existing functionality is NOT broken by this patch series. > > Assuming a system is configured to measure and appraise firmware > (rules below), with this change the firmware file will not be properly > measured and will fail signature verification. > > Sample IMA policy rules: > measure func=FIRMWARE_CHECK > appraise func=FIRMWARE_CHECK appraise_type=imasig Would a pre and post lsm hook for pread do it? Luis
