Verifying that a file hash is not blacklisted is currently only
supported for files with appended signatures (modsig). In the future,
this might change.
For now, the "appraise_flag" option is only appropriate for appraise
actions and its "blacklist" value is only appropriate when
CONFIG_IMA_APPRAISE_MODSIG is enabled and "appraise_flag=blacklist" is
only appropriate when "appraise_type=imasig|modsig" is also present.
Make this clear at policy load so that IMA policy authors don't assume
that other uses of "appraise_flag=blacklist" are supported.
Fixes:
273df864cf74 ("ima: Check against blacklisted hashes for files with modsig")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reivewed-by: Nayna Jain <nayna@linux.ibm.com>
Tested-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
return false;
}
+ /* Ensure that combinations of flags are compatible with each other */
+ if (entry->flags & IMA_CHECK_BLACKLIST &&
+ !(entry->flags & IMA_MODSIG_ALLOWED))
+ return false;
+
return true;
}
result = -EINVAL;
break;
case Opt_appraise_flag:
+ if (entry->action != APPRAISE) {
+ result = -EINVAL;
+ break;
+ }
+
ima_log_string(ab, "appraise_flag", args[0].from);
- if (strstr(args[0].from, "blacklist"))
+ if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
+ strstr(args[0].from, "blacklist"))
entry->flags |= IMA_CHECK_BLACKLIST;
+ else
+ result = -EINVAL;
break;
case Opt_permit_directio:
entry->flags |= IMA_PERMIT_DIRECTIO;