only check ftrace_enabled if cred->security is to be remapped

cormander · May 6, 2017 · 44e9f0a · 44e9f0a
1 parent 67c7f42
commit 44e9f0a
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Showing 2 changed files with 6 additions and 7 deletions.
diff --git a/fopskit.c b/fopskit.c
@@ -151,6 +151,12 @@ int fopskit_init_cred_security(struct fops_cred_handler *h) {
 	 * it's up to the caller of fopskit to decide how to handle this, based on fopskit_cred_remapped */
 	if (fopskit_sym_int("selinux_enabled") == 1 || fopskit_sym_int("selinux_disabled") == 1) {
 
+		/* remapping cred->security is only safe if ftrace is enabled */
+		if (fopskit_sym_int("ftrace_enabled") != 1) {
+			printk("fopskit: nable to insert module, ftrace is not enabled.\n");
+			return -ENOSYS;
+		}
+
 		/* save off init->cred->security */
 		init_sec = init->cred->security;
 

diff --git a/tpe_module.c b/tpe_module.c
@@ -186,13 +186,6 @@ static struct fops_cred_handler tpe_cred_handler = {
 static int __init tpe_init(void) {
 	int i, ret;
 
-	ret = fopskit_sym_int("ftrace_enabled");
-
-	if (!ret || IN_ERR(ret)) {
-		printk(PKPRE "Unable to insert module, ftrace is not enabled.\n");
-		return -ENOSYS;
-	}
-
 	ret = fopskit_init_cred_security(&tpe_cred_handler);
 
 	if (IN_ERR(ret))