On 2020-07-16 14:14:50, Mimi Zohar wrote:
> 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, ...
That makes sense. I'm not up to speed on the intent behind the blacklist
feature or where it may go in the future so I didn't think to add
anything along those lines.
If you are happy with the rest of the series, please feel free to append
this to the commit message. Otherwise, I can add it if I need to submit
a new revision of the series.
Tyler
>
> Mimi
>
> >
> > Fixes: 273df864cf74 ("ima: Check against blacklisted hashes for files with modsig")
> > Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx>
> > Cc: Nayna Jain <nayna@xxxxxxxxxxxxx>
>
> > ---
> >
> > * 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:
