Re: [PATCH v2 3/4] IMA: Add a test to verify measurement of certificate imported into a keyring

Petr Vorel
2020-08-17T11:09:17Z

Hi Mimi, Lakshmi,

> On Fri, 2020-08-07 at 22:46 +0200, Petr Vorel wrote:
> > From: Lachlan Sneff <t-josne@linux.microsoft.com>

> > diff --git a/testcases/kernel/security/integrity/ima/tests/ima_keys.sh b/testcases/kernel/security/integrity/ima/tests/ima_keys.sh
> > index 53c289054..30950904e 100755
> > --- a/testcases/kernel/security/integrity/ima/tests/ima_keys.sh
> > +++ b/testcases/kernel/security/integrity/ima/tests/ima_keys.sh

> > @@ -61,4 +65,52 @@ test1()
> > tst_res TPASS "specified keyrings were measured correctly"
> > }

> > +# Create a new keyring, import a certificate into it, and verify
> > +# that the certificate is measured correctly by IMA.
> > +test2()
> > +{
> > + tst_require_cmds evmctl keyctl openssl
> > +
> > + local cert_file="$TST_DATAROOT/x509_ima.der"
> > + local keyring_name="key_import_test"
> > + local temp_file="file.txt"
> > + local keyring_id
> > +
> > + tst_res TINFO "verify measurement of certificate imported into a keyring"
> > +
> > + if ! check_ima_policy_content "^measure.*func=KEY_CHECK.*keyrings=.*$keyring_name"; then
> > + tst_brk TCONF "IMA policy does not contain $keyring_name keyring"
> > + fi
> > +

> If the IMA policy contains multiple KEY_CHECK measurement policy rules
> it complains about "grep: Unmatched ( or \(".

> Sample rules:
> measure func=KEY_CHECK template=ima-buf
> keyrings=.ima|.builtin_trusted_keys
> measure func=KEY_CHECK template=ima-buf keyrings=key_import_test

Good catch, reproduced, working on fix (NOTE 2nd line is obviously joined to the
first one).

Caused by later code:
grep -E "($templates)*($keyrings)" $ASCII_MEASUREMENTS | while read line

> > + keyctl new_session > /dev/null
> > +
> > + keyring_id=$(keyctl newring $keyring_name @s) || \
> > + tst_brk TBROK "unable to create a new keyring"
> > +
> > + tst_is_num $keyring_id || \
> > + tst_brk TBROK "unable to parse the new keyring id"
> > +
> > + evmctl import $cert_file $keyring_id > /dev/null || \
> > + tst_brk TBROK "unable to import a certificate into $keyring_name keyring"

> "cert_file" needs to be updated from
> "ltp/testcases/kernel/security/integrity/ima/tests/datafiles/x509_ima.d
> er" to
> "ltp/testcases/kernel/security/integrity/ima/tests/../datafiles/ima_key
> s/x509_ima.der".

As Lakshmi wrote if you apply the fix, which I included in my branch
Lachlan_Sneff/ima_keys.sh-second-test.v1.fixes [1] it'd work.

Unlike kselftest, LTP requires installing and running from installed
directory. There was fix in the past allow running uninstalled test:
435d2fd82 ("ima: Rename the folder name for policy files to datafiles"), but I
broke that in this patchset ("IMA: Refactor datafiles directory").

Maybe fixing a code in tst_test.sh
if [ -z "$LTPROOT" ]; then
export LTPROOT="$PWD"
export TST_DATAROOT="$LTPROOT/datafiles"
else
export TST_DATAROOT="$LTPROOT/testcases/data/$TST_ID"
fi

To allow to redefine it, for local testing:
if [ -z "$TST_DATAROOT" ]; then
if [ -z "$LTPROOT" ]; then
export LTPROOT="$PWD"
export TST_DATAROOT="$LTPROOT/datafiles"
else
export TST_DATAROOT="$LTPROOT/testcases/data/$TST_ID"
fi
fi

because datafile layout does not expect subdirectory. I also hate the makefile
helper, which requires to have special directory, datafiles just require some
rethinking.

> On failure to open the file,
> errno: No such file or directory (2)

The rest is obviously not relevant (was just a hint for problems caused with
other LSM).
> ima_keys 2 TBROK: unable to import a certificate into key_import_test keyring
> ima_keys 2 TINFO: SELinux enabled in enforcing mode, this may affect test results
> ima_keys 2 TINFO: it can be disabled with TST_DISABLE_SELINUX=1 (requires super/root)
> ima_keys 2 TINFO: install seinfo to find used SELinux profiles
> ima_keys 2 TINFO: loaded SELinux profiles: none

Kind regards,
Petr

[1] https://github.com/pevik/ltp/tree/Lachlan_Sneff/ima_keys.sh-second-test.v1.fixes