On Fri, 2024-09-06 at 12:45 +0300, Jarkko Sakkinen wrote: > On Thu Sep 5, 2024 at 6:25 PM EEST, Roberto Sassu wrote: > > From: Roberto Sassu <roberto.sassu@xxxxxxxxxx> > > > > Specify the 'digest_cache_measure' boot-time policy with 'ima_policy=' in > > the kernel command line to add the following rule at the beginning of the > > IMA policy, before other rules: > > > > measure func=DIGEST_LIST_CHECK pcr=12 > > > > which will measure digest lists into PCR 12 (or the value in > > CONFIG_IMA_DIGEST_CACHE_MEASURE_PCR_IDX). > > > > Specify 'digest_cache_appraise' to add the following rule at the beginning, > > before other rules: > > > > appraise func=DIGEST_LIST_CHECK appraise_type=imasig|modsig > > > > which will appraise digest lists with IMA signatures or module-style > > appended signatures. > > > > Adding those rule at the beginning rather than at the end is necessary to > > ensure that digest lists are measured and appraised in the initial ram > > disk, which would be otherwise prevented by the dont_ rules. > > > > Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx> > > --- > > .../admin-guide/kernel-parameters.txt | 10 +++++- > > security/integrity/ima/Kconfig | 10 ++++++ > > security/integrity/ima/ima_policy.c | 35 +++++++++++++++++++ > > 3 files changed, 54 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index 09126bb8cc9f..afaaf125a237 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2077,7 +2077,8 @@ > > ima_policy= [IMA] > > The builtin policies to load during IMA setup. > > Format: "tcb | appraise_tcb | secure_boot | > > - fail_securely | critical_data" > > + fail_securely | critical_data | > > + digest_cache_measure | digest_cache_appraise" > > > > The "tcb" policy measures all programs exec'd, files > > mmap'd for exec, and all files opened with the read > > @@ -2099,6 +2100,13 @@ > > The "critical_data" policy measures kernel integrity > > critical data. > > > > + The "digest_cache_measure" policy measures digest lists > > + into PCR 12 (can be changed with kernel config). > > + > > + The "digest_cache_appraise" policy appraises digest > > + lists with IMA signatures or module-style appended > > + signatures. > > + > > ima_tcb [IMA] Deprecated. Use ima_policy= instead. > > Load a policy which meets the needs of the Trusted > > Computing Base. This means IMA will measure all > > Must be updated as a separate commit as kernel-parameters.txt not > part of IMA. Consider it as a different subsystem in this context. Can be done, but this would be more like an atomic change in case the patch is reverted. Thanks Roberto
