[LTP] [PATCH] ima_violations.sh: Another fix of condition evaluation

[Petr Vorel]

> On Thu, 2025-12-11 at 12:10 +0100, Petr Vorel wrote:
> > c0c35509f9 was not enough to fix evaluation against empty
> > $expected_violations:

> > ima_violations 1 TINFO: verify open writers violation
> > /opt/ltp/testcases/bin/ima_violations.sh: line 96: [: 0: unary operator expected

> > Therefore split checks into two if.

> > Also improvements (readability)
> > * shorten line length with saving subtraction into variable
> > * evaluate empty variable with ${:-}

> > Fixes: 726ed71905 ("ima_violations.sh: Update validate() to support multiple violations")
> > Reported-by: Martin Doucha <mdoucha@suse.cz>
> > Signed-off-by: Petr Vorel <pvorel@suse.cz>

> Thanks, Martin, Petr.  LGTM

Thanks! FYI merged with simpler code suggested by Andrea.

> > ---
> > NOTE: this was found on old SLES 4.4 based kernel which does not log
> > validations. But missing validations might be just a Secure Boot related
> > setup problem:

> > $ mokutil --sb-state
> > Secure Boot: EFI variables not supported on SUT

> > Events are logged when Secure Boot is off:
> > $ mokutil --sb-state
> > SecureBoot disabled

> > Or maybe violations worked differently on the old kernel (I remember
> > only 6.15 change).

> Violations only occur when there are policy rules containing "func=FILE_CHECK"
> defined.  The secure boot mode should only affects the arch specific policies,
> which do not include "func=FILE_CHECK" rules.  There is a slight difference
> between the builtin the original "ima_tcb" and newer "ima_policy=tcb" policies,
> which might affect violations.

Thanks for the hints! I'll have to dig more into tthe problem to see what is
wrong.

Anyway at least for example policy I see the differences between the old [1] and
new [2]:

-measure func=FILE_CHECK mask=MAY_READ uid=0
+measure func=FILE_CHECK mask=^MAY_READ euid=0
+measure func=FILE_CHECK mask=^MAY_READ uid=0    # root opened r/o, r/w

I guess I'll just add for older kernels this example policy:
measure func=FILE_CHECK mask=MAY_READ uid=0

Kind regards,
Petr

[1] https://ima-doc.readthedocs.io/en/latest/ima-policy.html#ima-policy-tcb
[2] https://ima-doc.readthedocs.io/en/latest/ima-policy.html#ima-tcb