ima: fallback to MODULE_SIG_ENFORCE for existing kernel module syscall

The new kernel module syscall appraises kernel modules based on policy. If the IMA policy requires kernel module checking, fallback to module signature enforcing for the existing syscall. Without CONFIG_MODULE_SIG_FORCE enabled, the kernel module's integrity is unknown, return -EACCES. Changelog v1: - Fix ima_module_check() return result (Tetsuo Handa) Reported-by: Tetsuo Handa <[email protected]> Reviewed-by: Tetsuo Handa <[email protected]> Signed-off-by: Mimi Zohar <[email protected]>
cbmeeks · Dec 24, 2012 · a7f2a36 · a7f2a36
1 parent a49f0d1
commit a7f2a36
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Showing 3 changed files with 11 additions and 5 deletions.
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
@@ -139,6 +139,7 @@ void ima_delete_rules(void);
 /* Appraise integrity measurements */
 #define IMA_APPRAISE_ENFORCE	0x01
 #define IMA_APPRAISE_FIX	0x02
+#define IMA_APPRAISE_MODULES	0x04
 
 #ifdef CONFIG_IMA_APPRAISE
 int ima_appraise_measurement(struct integrity_iint_cache *iint,

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
@@ -291,11 +291,15 @@ EXPORT_SYMBOL_GPL(ima_file_check);
  */
 int ima_module_check(struct file *file)
 {
-	int rc;
+	int rc = 0;
 
-	if (!file)
-		rc = INTEGRITY_UNKNOWN;
-	else
+	if (!file) {
+		if (ima_appraise & IMA_APPRAISE_MODULES) {
+#ifndef CONFIG_MODULE_SIG_FORCE
+			rc = -EACCES;	/* INTEGRITY_UNKNOWN */
+#endif
+		}
+	} else
 		rc = process_measurement(file, file->f_dentry->d_name.name,
 					 MAY_EXEC, MODULE_CHECK);
 	return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0;

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
@@ -523,7 +523,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 	}
 	if (!result && (entry->action == UNKNOWN))
 		result = -EINVAL;
-
+	else if (entry->func == MODULE_CHECK)
+		ima_appraise |= IMA_APPRAISE_MODULES;
 	audit_log_format(ab, "res=%d", !result);
 	audit_log_end(ab);
 	return result;