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

Mimi Zohar
2020-08-17T03:22:10Z

Hi Petr, Lachlan,

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

> + 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".

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

Mimi

> +
> + grep $keyring_name $ASCII_MEASUREMENTS | tail -n1 | cut -d' ' -f6 | \
> + xxd -r -p > $temp_file
> +
> + if [ ! -s $temp_file ]; then
> + tst_res TFAIL "keyring $keyring_name not found in $ASCII_MEASUREMENTS"
> + return
> + fi
> +
> + if ! openssl x509 -in $temp_file -inform der > /dev/null; then
> + tst_res TFAIL "logged certificate is not a valid x509 certificate"
> + return
> + fi
> +
> + if cmp -s $temp_file $cert_file; then
> + tst_res TPASS "logged certificate matches the original"
> + else
> + tst_res TFAIL "logged certificate does not match original"
> + fi
> +}
> +
> tst_run