On 2/6/2024 6:02 PM, Dan Williams wrote:
James Bottomley wrote:
There isn't really anything more complex about an interface that takes
a log entry, and does the record an extend, than an interface which
takes a PCR extension value. So best practice would say that you
should create the ABI that you can't get wrong (log and record) rather
than creating one that causes additional problems for userspace.
Agree, there's no need for the kernel to leave deliberately pointy edges
for userspace to trip over.
Cedric, almost every time we, kernel community, build an interface where
userspace says "trust us, we know what we are doing" it inevitably
results later in "whoops, turns out it would have helped if the kernel
enforced structure here". So the log ABI adds that structure for the
primary use cases.
Dan, I agree with your statement generally. But with the precedent of
TPM module not maintaining a log, I just wonder if the addition of log
would cause problems or force more changes to existing usages than
necessary. For example, IMA has its own log and if changed to use RTMR,
how would those 2 logs interoperate? We would also need to decide on a
log format that can accommodate all applications.
