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 <tyhi...@linux.microsoft.com>
> Cc: Nayna Jain <na...@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:
