Messages in this thread | | | Date | Thu, 16 Jul 2020 13:20:57 -0500 | From | Tyler Hicks <> | Subject | Re: [PATCH v3 07/12] ima: Fail rule parsing when appraise_flag=blacklist is unsupportable |
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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@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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