So far the variable was set as soon as one of the SMBIOS structures
(types 1, 2 and 11) was measured, and a later failure on another only
logged.The original intent was to prevent sd-stub from measuring these
things a second time after sd-boot already did.
This PR adds a second consumer: in a confidential VM, PID 1 takes the
variable as confirmation that the SMBIOS OEM strings are covered by
PCR 1 before it imports credentials from them. Make the loader provide
that guarantee and leave the variable unset if any structure could not
be measured, which also matches how the documentation already describes
it.
The effect on the existing consumer is limited to boots with a
measurement failure: when sd-boot fails to measure some of the structs
and then chainloads sd-stub, sd-stub measures the structs sd-boot was
able to measure a second time. Previously it would have left the
incomplete measurement as is. In that situation PCR 1 already didn't
match the expected value before (events missing), and after this change
it still won't (additional events), so anything bound to it, such as a
pcrlock policy, does not match either way.
Signed-off-by: Paul Meyer <katexochen0@gmail.com>
(cherry picked from commit 224a37a47b)
Paul Meyer
5d504e55cf
