1 files changed, 140 insertions, 23 deletions

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 7b53f2ca58e2..6df7f641ff66 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -76,6 +76,7 @@ struct ima_rule_entry {
 		int type;	/* audit type */
 	} lsm[MAX_LSM_RULES];
 	char *fsname;
+	struct ima_template_desc *template;
 };
 
 /*
@@ -195,7 +196,7 @@ static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
 };
 
 /* An array of architecture specific rules */
-struct ima_rule_entry *arch_policy_entry __ro_after_init;
+static struct ima_rule_entry *arch_policy_entry __ro_after_init;
 
 static LIST_HEAD(ima_default_rules);
 static LIST_HEAD(ima_policy_rules);
@@ -245,31 +246,113 @@ static int __init default_appraise_policy_setup(char *str)
 }
 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 
+static void ima_lsm_free_rule(struct ima_rule_entry *entry)
+{
+	int i;
+
+	for (i = 0; i < MAX_LSM_RULES; i++) {
+		kfree(entry->lsm[i].rule);
+		kfree(entry->lsm[i].args_p);
+	}
+	kfree(entry);
+}
+
+static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
+{
+	struct ima_rule_entry *nentry;
+	int i, result;
+
+	nentry = kmalloc(sizeof(*nentry), GFP_KERNEL);
+	if (!nentry)
+		return NULL;
+
+	/*
+	 * Immutable elements are copied over as pointers and data; only
+	 * lsm rules can change
+	 */
+	memcpy(nentry, entry, sizeof(*nentry));
+	memset(nentry->lsm, 0, FIELD_SIZEOF(struct ima_rule_entry, lsm));
+
+	for (i = 0; i < MAX_LSM_RULES; i++) {
+		if (!entry->lsm[i].rule)
+			continue;
+
+		nentry->lsm[i].type = entry->lsm[i].type;
+		nentry->lsm[i].args_p = kstrdup(entry->lsm[i].args_p,
+						GFP_KERNEL);
+		if (!nentry->lsm[i].args_p)
+			goto out_err;
+
+		result = security_filter_rule_init(nentry->lsm[i].type,
+						   Audit_equal,
+						   nentry->lsm[i].args_p,
+						   &nentry->lsm[i].rule);
+		if (result == -EINVAL)
+			pr_warn("ima: rule for LSM \'%d\' is undefined\n",
+				entry->lsm[i].type);
+	}
+	return nentry;
+
+out_err:
+	ima_lsm_free_rule(nentry);
+	return NULL;
+}
+
+static int ima_lsm_update_rule(struct ima_rule_entry *entry)
+{
+	struct ima_rule_entry *nentry;
+
+	nentry = ima_lsm_copy_rule(entry);
+	if (!nentry)
+		return -ENOMEM;
+
+	list_replace_rcu(&entry->list, &nentry->list);
+	synchronize_rcu();
+	ima_lsm_free_rule(entry);
+
+	return 0;
+}
+
 /*
  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
- * the reloaded LSM policy.  We assume the rules still exist; and BUG_ON() if
- * they don't.
+ * the reloaded LSM policy.
  */
 static void ima_lsm_update_rules(void)
 {
-	struct ima_rule_entry *entry;
-	int result;
-	int i;
+	struct ima_rule_entry *entry, *e;
+	int i, result, needs_update;
 
-	list_for_each_entry(entry, &ima_policy_rules, list) {
+	list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
+		needs_update = 0;
 		for (i = 0; i < MAX_LSM_RULES; i++) {
-			if (!entry->lsm[i].rule)
-				continue;
-			result = security_filter_rule_init(entry->lsm[i].type,
-							   Audit_equal,
-							   entry->lsm[i].args_p,
-							   &entry->lsm[i].rule);
-			BUG_ON(!entry->lsm[i].rule);
+			if (entry->lsm[i].rule) {
+				needs_update = 1;
+				break;
+			}
+		}
+		if (!needs_update)
+			continue;
+
+		result = ima_lsm_update_rule(entry);
+		if (result) {
+			pr_err("ima: lsm rule update error %d\n",
+				result);
+			return;
 		}
 	}
 }
 
+int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
+			  void *lsm_data)
+{
+	if (event != LSM_POLICY_CHANGE)
+		return NOTIFY_DONE;
+
+	ima_lsm_update_rules();
+	return NOTIFY_OK;
+}
+
 /**
  * ima_match_rules - determine whether an inode matches the measure rule.
  * @rule: a pointer to a rule
@@ -287,6 +370,11 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 {
 	int i;
 
+	if (func == KEXEC_CMDLINE) {
+		if ((rule->flags & IMA_FUNC) && (rule->func == func))
+			return true;
+		return false;
+	}
 	if ((rule->flags & IMA_FUNC) &&
 	    (rule->func != func && func != POST_SETATTR))
 		return false;
@@ -323,11 +411,10 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 	for (i = 0; i < MAX_LSM_RULES; i++) {
 		int rc = 0;
 		u32 osid;
-		int retried = 0;
 
 		if (!rule->lsm[i].rule)
 			continue;
-retry:
+
 		switch (i) {
 		case LSM_OBJ_USER:
 		case LSM_OBJ_ROLE:
@@ -348,11 +435,6 @@ retry:
 		default:
 			break;
 		}
-		if ((rc < 0) && (!retried)) {
-			retried = 1;
-			ima_lsm_update_rules();
-			goto retry;
-		}
 		if (!rc)
 			return false;
 	}
@@ -393,6 +475,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * @func: IMA hook identifier
  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
  * @pcr: set the pcr to extend
+ * @template_desc: the template that should be used for this rule
  *
  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
  * conditions.
@@ -402,7 +485,8 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * than writes so ima_match_policy() is classical RCU candidate.
  */
 int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
-		     enum ima_hooks func, int mask, int flags, int *pcr)
+		     enum ima_hooks func, int mask, int flags, int *pcr,
+		     struct ima_template_desc **template_desc)
 {
 	struct ima_rule_entry *entry;
 	int action = 0, actmask = flags | (flags << 1);
@@ -434,6 +518,11 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
 		if ((pcr) && (entry->flags & IMA_PCR))
 			*pcr = entry->pcr;
 
+		if (template_desc && entry->template)
+			*template_desc = entry->template;
+		else if (template_desc)
+			*template_desc = ima_template_desc_current();
+
 		if (!actmask)
 			break;
 	}
@@ -672,7 +761,7 @@ enum {
 	Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
 	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
 	Opt_appraise_type, Opt_permit_directio,
-	Opt_pcr, Opt_err
+	Opt_pcr, Opt_template, Opt_err
 };
 
 static const match_table_t policy_tokens = {
@@ -706,6 +795,7 @@ static const match_table_t policy_tokens = {
 	{Opt_appraise_type, "appraise_type=%s"},
 	{Opt_permit_directio, "permit_directio"},
 	{Opt_pcr, "pcr=%s"},
+	{Opt_template, "template=%s"},
 	{Opt_err, NULL}
 };
 
@@ -759,6 +849,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 	char *from;
 	char *p;
 	bool uid_token;
+	struct ima_template_desc *template_desc;
 	int result = 0;
 
 	ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
@@ -866,6 +957,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 				entry->func = KEXEC_INITRAMFS_CHECK;
 			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
 				entry->func = POLICY_CHECK;
+			else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
+				entry->func = KEXEC_CMDLINE;
 			else
 				result = -EINVAL;
 			if (!result)
@@ -1055,6 +1148,28 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 				entry->flags |= IMA_PCR;
 
 			break;
+		case Opt_template:
+			ima_log_string(ab, "template", args[0].from);
+			if (entry->action != MEASURE) {
+				result = -EINVAL;
+				break;
+			}
+			template_desc = lookup_template_desc(args[0].from);
+			if (!template_desc || entry->template) {
+				result = -EINVAL;
+				break;
+			}
+
+			/*
+			 * template_desc_init_fields() does nothing if
+			 * the template is already initialised, so
+			 * it's safe to do this unconditionally
+			 */
+			template_desc_init_fields(template_desc->fmt,
+						 &(template_desc->fields),
+						 &(template_desc->num_fields));
+			entry->template = template_desc;
+			break;
 		case Opt_err:
 			ima_log_string(ab, "UNKNOWN", p);
 			result = -EINVAL;
@@ -1330,6 +1445,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 			}
 		}
 	}
+	if (entry->template)
+		seq_printf(m, "template=%s ", entry->template->name);
 	if (entry->flags & IMA_DIGSIG_REQUIRED)
 		seq_puts(m, "appraise_type=imasig ");
 	if (entry->flags & IMA_PERMIT_DIRECTIO)