On 21 November 2016 at 16:26, Josh Boyer <jwbo...@fedoraproject.org> wrote: > On Mon, Nov 21, 2016 at 11:18 AM, Ard Biesheuvel > <ard.biesheu...@linaro.org> wrote: >> On 16 November 2016 at 18:11, David Howells <dhowe...@redhat.com> wrote: >>> From: Josh Boyer <jwbo...@fedoraproject.org> >>> >>> If a user tells shim to not use the certs/hashes in the UEFI db variable >>> for verification purposes, shim will set a UEFI variable called >>> MokIgnoreDB. Have the uefi import code look for this and ignore the db >>> variable if it is found. >>> >> >> Similar concern as in the previous patch: it appears to me that you >> can DoS a machine by setting MokIgnoreDB if, e.g., its modules are >> signed against a cert that resides in db, and shim/mokmanager are not >> being used. > > If shim/mokmanager aren't used, then you can't actually modify > MokIgnoreDB. Again, it requires physical access and a reboot into > mokmanager to actually take effect. >
This does the trick as well printf "\x07\x00\x00\x00\x01" > /sys/firmware/efi/efivars/MokIgnoreDB-605dab50-e046-4300-abb6-3dd810dd8b23
