---

yaml
---
r: 146433
b: refs/heads/master
c: 5789ba3
h: refs/heads/master
i:
  146431: 943ba7b
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c5642f4bbae30122beb696e723f6da273caa570e
+refs/heads/master: 5789ba3bd0a3cd20df5980ebf03358f2eb44fd67

trunk/Documentation/kernel-parameters.txt

@@ -914,6 +914,12 @@ and is between 256 and 4096 characters. It is defined in the file
 			Formt: { "sha1" | "md5" }
 			default: "sha1"
 
+	ima_tcb		[IMA]
+			Load a policy which meets the needs of the Trusted
+			Computing Base.  This means IMA will measure all
+			programs exec'd, files mmap'd for exec, and all files
+			opened for read by uid=0.
+
 	in2000=		[HW,SCSI]
 			See header of drivers/scsi/in2000.c.
 

trunk/security/integrity/ima/ima_policy.c

@@ -45,9 +45,17 @@ struct ima_measure_rule_entry {
 	} lsm[MAX_LSM_RULES];
 };
 
-/* Without LSM specific knowledge, the default policy can only be
+/*
+ * Without LSM specific knowledge, the default policy can only be
  * written in terms of .action, .func, .mask, .fsmagic, and .uid
  */
+
+/*
+ * The minimum rule set to allow for full TCB coverage.  Measures all files
+ * opened or mmap for exec and everything read by root.  Dangerous because
+ * normal users can easily run the machine out of memory simply building
+ * and running executables.
+ */
 static struct ima_measure_rule_entry default_rules[] = {
 	{.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
 	{.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
@@ -59,6 +67,8 @@ static struct ima_measure_rule_entry default_rules[] = {
 	 .flags = IMA_FUNC | IMA_MASK},
 	{.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC,
 	 .flags = IMA_FUNC | IMA_MASK},
+	{.action = MEASURE,.func = PATH_CHECK,.mask = MAY_READ,.uid = 0,
+	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
 };
 
 static LIST_HEAD(measure_default_rules);
@@ -67,6 +77,14 @@ static struct list_head *ima_measure;
 
 static DEFINE_MUTEX(ima_measure_mutex);
 
+static bool ima_use_tcb __initdata;
+static int __init default_policy_setup(char *str)
+{
+	ima_use_tcb = 1;
+	return 1;
+}
+__setup("ima_tcb", default_policy_setup);
+
 /**
  * ima_match_rules - determine whether an inode matches the measure rule.
  * @rule: a pointer to a rule
@@ -162,9 +180,15 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
  */
 void ima_init_policy(void)
 {
-	int i;
+	int i, entries;
+
+	/* if !ima_use_tcb set entries = 0 so we load NO default rules */
+	if (ima_use_tcb)
+		entries = ARRAY_SIZE(default_rules);
+	else
+		entries = 0;
 
-	for (i = 0; i < ARRAY_SIZE(default_rules); i++)
+	for (i = 0; i < entries; i++)
 		list_add_tail(&default_rules[i].list, &measure_default_rules);
 	ima_measure = &measure_default_rules;
 }