On Wed, Nov 27, 2024 at 10:51:11AM +0100, Roberto Sassu wrote:

For eBPF programs we are also in a need for a better way to
measure/appraise them.

I am confused now, I was under the impression this "Integrity Digest
Cache" is just a special thing for LSMs, and so I was under the
impression that kernel_read_file() lsm hook already would take care
of eBPF programs.

Now, I'm trying to follow you on the additional kernel_read_file()
calls. I agree with you, if a parser tries to open again the file that
is being verified it would cause a deadlock in IMA (since the inode
mutex is already locked for verifying the original file).

Just document this on the parser as a requirement.

quoted

quoted

Supporting kernel modules opened the road for new deadlocks, since one
can ask a digest list to verify a kernel module, but that digest list
requires the same kernel module. That is why the in-kernel mechanism is
100% reliable,

Are users of this infrastructure really in need of modules for these
parsers?

I planned to postpone this to later, and introduced two parsers built-
in (TLV and RPM). However, due to Linus's concern regarding the RPM
parser, I moved it out in a kernel module.

OK this should be part of the commit log, ie that it is not desirable to
have an rpm parser in-kernel for some users.

  Luis