On Wed, 2016-08-31 at 13:50 -0700, Andrew Morton wrote: > On Tue, 30 Aug 2016 18:40:02 -0400 Mimi Zohar <zohar at linux.vnet.ibm.com> wrote: > > > The TPM PCRs are only reset on a hard reboot. In order to validate a > > TPM's quote after a soft reboot (eg. kexec -e), the IMA measurement list > > of the running kernel must be saved and then restored on the subsequent > > boot, possibly of a different architecture. > > > > The existing securityfs binary_runtime_measurements file conveniently > > provides a serialized format of the IMA measurement list. This patch > > set serializes the measurement list in this format and restores it. > > > > Up to now, the binary_runtime_measurements was defined as architecture > > native format. The assumption being that userspace could and would > > handle any architecture conversions. With the ability of carrying the > > measurement list across kexec, possibly from one architecture to a > > different one, the per boot architecture information is lost and with it > > the ability of recalculating the template digest hash. To resolve this > > problem, without breaking the existing ABI, this patch set introduces > > the boot command line option "ima_canonical_fmt", which is arbitrarily > > defined as little endian. > > > > The need for this boot command line option will be limited to the > > existing version 1 format of the binary_runtime_measurements. > > Subsequent formats will be defined as canonical format (eg. TPM 2.0 > > support for larger digests). > > > > This patch set pre-req's Thiago Bauermann's "kexec_file: Add buffer > > hand-over for the next kernel" patch set. > > > > These patches can also be found in the next-kexec-restore branch of: > > git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git > > I'll merge these into -mm to get some linux-next exposure. I don't > know what your upstream merge plans will be? Sounds good. I'm hoping to get some review/comments on this patch set as well. At the moment, I'm chasing down a kernel test robot report from this afternoon. Mimi
