Messages in this thread | | | Subject | Re: [PATCH v3 07/12] ima: Fail rule parsing when appraise_flag=blacklist is unsupportable | From | Mimi Zohar <> | Date | Thu, 16 Jul 2020 14:14:50 -0400 |
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On Thu, 2020-07-09 at 01:19 -0500, Tyler Hicks wrote: > 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.
The code looks correct, but this patch description could be written at a higher level. Perhaps it just needs to be prefixed with something like this:
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, ...
Mimi
> > Fixes: 273df864cf74 ("ima: Check against blacklisted hashes for files with modsig") > Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com> > Cc: Nayna Jain <nayna@linux.ibm.com>
> --- > > * v3 > - New patch > > security/integrity/ima/ima_policy.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c > index 81da02071d41..9842e2e0bc6d 100644 > --- a/security/integrity/ima/ima_policy.c > +++ b/security/integrity/ima/ima_policy.c > @@ -1035,6 +1035,11 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) > 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; > } > > @@ -1371,8 +1376,14 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) > 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; > break; > case Opt_permit_directio:
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