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-rw-r--r--security/integrity/ima/ima_policy.c48
1 files changed, 34 insertions, 14 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index b5291ad5ef5..e1278399b34 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -45,24 +45,30 @@ 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 = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
{.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
{.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
{.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
- {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,
- .flags = IMA_FSMAGIC},
- {.action = DONT_MEASURE,.fsmagic = 0xF97CFF8C,.flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
{.action = MEASURE,.func = FILE_MMAP,.mask = MAY_EXEC,
.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}
+ .flags = IMA_FUNC | IMA_MASK | IMA_UID},
};
static LIST_HEAD(measure_default_rules);
@@ -71,6 +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
@@ -96,7 +110,7 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
if ((rule->flags & IMA_UID) && rule->uid != tsk->cred->uid)
return false;
for (i = 0; i < MAX_LSM_RULES; i++) {
- int rc;
+ int rc = 0;
u32 osid, sid;
if (!rule->lsm[i].rule)
@@ -109,7 +123,7 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
security_inode_getsecid(inode, &osid);
rc = security_filter_rule_match(osid,
rule->lsm[i].type,
- AUDIT_EQUAL,
+ Audit_equal,
rule->lsm[i].rule,
NULL);
break;
@@ -119,7 +133,7 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
security_task_getsecid(tsk, &sid);
rc = security_filter_rule_match(sid,
rule->lsm[i].type,
- AUDIT_EQUAL,
+ Audit_equal,
rule->lsm[i].rule,
NULL);
default:
@@ -164,11 +178,17 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
* ima_measure points to either the measure_default_rules or the
* the new measure_policy_rules.
*/
-void ima_init_policy(void)
+void __init 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;
}
@@ -227,7 +247,7 @@ static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry,
entry->lsm[lsm_rule].type = audit_type;
result = security_filter_rule_init(entry->lsm[lsm_rule].type,
- AUDIT_EQUAL, args,
+ Audit_equal, args,
&entry->lsm[lsm_rule].rule);
return result;
}