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From: Tyler Hicks <tyhicks@linux.microsoft.com>
To: Mimi Zohar <zohar@linux.ibm.com>,
	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
	Prakhar Srivastava <prsriva02@gmail.com>,
	linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	Nayna Jain <nayna@linux.ibm.com>
Subject: [PATCH v3 07/12] ima: Fail rule parsing when appraise_flag=blacklist is unsupportable
Date: Thu,  9 Jul 2020 01:19:06 -0500	[thread overview]
Message-ID: <20200709061911.954326-8-tyhicks@linux.microsoft.com> (raw)
In-Reply-To: <20200709061911.954326-1-tyhicks@linux.microsoft.com>

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>
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:
-- 
2.25.1


  parent reply	other threads:[~2020-07-09  6:20 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09  6:18 [PATCH v3 00/12] ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 01/12] ima: Have the LSM free its audit rule Tyler Hicks
2020-07-17 19:20   ` Nayna
2020-07-17 19:24     ` Tyler Hicks
2020-07-19 11:02       ` Mimi Zohar
2020-07-09  6:19 ` [PATCH v3 02/12] ima: Free the entire rule when deleting a list of rules Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 03/12] ima: Free the entire rule if it fails to parse Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 04/12] ima: Fail rule parsing when buffer hook functions have an invalid action Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 05/12] ima: Fail rule parsing when the KEXEC_CMDLINE hook is combined with an invalid cond Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 06/12] ima: Fail rule parsing when the KEY_CHECK " Tyler Hicks
2020-07-17 18:56   ` Nayna
2020-07-17 19:18     ` Tyler Hicks
2020-07-17 23:39       ` Tyler Hicks
2020-07-09  6:19 ` Tyler Hicks [this message]
2020-07-16 18:14   ` [PATCH v3 07/12] ima: Fail rule parsing when appraise_flag=blacklist is unsupportable Mimi Zohar
2020-07-16 18:20     ` Tyler Hicks
     [not found]   ` <76d2b27b-3b59-1852-046a-b1718c62b167@linux.vnet.ibm.com>
2020-07-17 18:11     ` Tyler Hicks
2020-07-20 17:02       ` Nayna
2020-07-09  6:19 ` [PATCH v3 08/12] ima: Shallow copy the args_p member of ima_rule_entry.lsm elements Tyler Hicks
2020-07-17 15:35   ` Konsta Karsisto
2020-07-17 16:51     ` Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 09/12] ima: Use correct type for " Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 10/12] ima: Move comprehensive rule validation checks out of the token parser Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 11/12] ima: Use the common function to detect LSM conditionals in a rule Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 12/12] ima: Support additional conditionals in the KEXEC_CMDLINE hook function Tyler Hicks
2020-07-17  4:31 ` [PATCH v3 00/12] ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support Mimi Zohar
2020-07-17  4:34   ` Tyler Hicks
2020-07-20 21:38 ` Mimi Zohar

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