kernel: stop intercepting devpts inode permission via LSM

* Somehow, it just does not work properly. (sometimes)

Signed-off-by: rsuntk <rsuntk@yukiprjkt.my.id>

kernel/core_hook.c

@@ -830,19 +830,6 @@ static int ksu_task_fix_setuid(struct cred *new, const struct cred *old,
 }
 
 #ifndef MODULE
-
-extern int __ksu_handle_devpts(struct inode *inode);
-static int ksu_inode_permission(struct inode *inode, int mask)
-{
-	if (unlikely(inode->i_sb && inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)) {
-#ifdef CONFIG_KSU_DEBUG
-		pr_info("%s: devpts inode accessed with mask: %x\n", __func__, mask);
-#endif
-		__ksu_handle_devpts(inode);
-	}
-	return 0;
-}
-
 static struct security_hook_list ksu_hooks[] = {
 	LSM_HOOK_INIT(task_prctl, ksu_task_prctl),
 	LSM_HOOK_INIT(inode_rename, ksu_inode_rename),

kernel/sucompat.c

@@ -23,7 +23,7 @@
 extern void escape_to_root();
 
 #ifndef CONFIG_KSU_KPROBES_HOOK
-static bool ksu_sucompat_non_kp __read_mostly = true;
+static bool ksu_sucompat_hook_state __read_mostly = true;
 #endif
 
 static void __user *userspace_stack_buffer(const void *d, size_t len)
@@ -55,7 +55,7 @@ int ksu_handle_faccessat(int *dfd, const char __user **filename_user, int *mode,
 	const char su[] = SU_PATH;
 
 #ifndef CONFIG_KSU_KPROBES_HOOK
-	if (!ksu_sucompat_non_kp) {
+	if (!ksu_sucompat_hook_state) {
  		return 0;
  	}
 #endif
@@ -82,7 +82,7 @@ int ksu_handle_stat(int *dfd, const char __user **filename_user, int *flags)
 	const char su[] = SU_PATH;
 
 #ifndef CONFIG_KSU_KPROBES_HOOK
-	if (!ksu_sucompat_non_kp) {
+	if (!ksu_sucompat_hook_state) {
  		return 0;
  	}
 #endif
@@ -131,7 +131,7 @@ int ksu_handle_execveat_sucompat(int *fd, struct filename **filename_ptr,
 	const char su[] = SU_PATH;
 
 #ifndef CONFIG_KSU_KPROBES_HOOK
-	if (!ksu_sucompat_non_kp) {
+	if (!ksu_sucompat_hook_state) {
  		return 0;
  	}
 #endif
@@ -165,7 +165,7 @@ int ksu_handle_execve_sucompat(int *fd, const char __user **filename_user,
 	char path[sizeof(su) + 1];
 
 #ifndef CONFIG_KSU_KPROBES_HOOK
-	if (!ksu_sucompat_non_kp){
+	if (!ksu_sucompat_hook_state){
  		return 0;
  	}
 #endif
@@ -189,8 +189,13 @@ int ksu_handle_execve_sucompat(int *fd, const char __user **filename_user,
 	return 0;
 }
 
-static int ksu_inline_handle_devpts(struct inode *inode)
+int ksu_handle_devpts(struct inode *inode)
 {
+#ifndef CONFIG_KSU_KPROBES_HOOK
+	if (!ksu_sucompat_hook_state)
+		return 0;
+#endif
+
 	if (!current->mm) {
 		return 0;
 	}
@@ -214,22 +219,6 @@ static int ksu_inline_handle_devpts(struct inode *inode)
 	return 0;
 }
 
-int __ksu_handle_devpts(struct inode *inode)
-{
-#ifndef CONFIG_KSU_KPROBES_HOOK
-	if (!ksu_sucompat_non_kp) {
-		return 0;
-	}
-#endif
-	return ksu_inline_handle_devpts(inode);
-}
-
-// dead code, we are phasing out ksu_handle_devpts for LSM hooks.
-int __maybe_unused ksu_handle_devpts(struct inode *inode)
-{
-	return 0;
-}
-
 #ifdef CONFIG_KSU_KPROBES_HOOK
 static int faccessat_handler_pre(struct kprobe *p, struct pt_regs *regs)
 {
@@ -263,7 +252,6 @@ static int execve_handler_pre(struct kprobe *p, struct pt_regs *regs)
 					  NULL);
 }
 
-#ifdef MODULE
 static struct kprobe *su_kps[4];
 static int pts_unix98_lookup_pre(struct kprobe *p, struct pt_regs *regs)
 {
@@ -275,11 +263,8 @@ static int pts_unix98_lookup_pre(struct kprobe *p, struct pt_regs *regs)
 	inode = (struct inode *)PT_REGS_PARM2(regs);
 #endif
 
-	return ksu_inline_handle_devpts(inode);
+	return ksu_handle_devpts(inode);
 }
-#else
-static struct kprobe *su_kps[3];
-#endif
 
 static struct kprobe *init_kprobe(const char *name,
 				  kprobe_pre_handler_t handler)
@@ -320,11 +305,9 @@ void ksu_sucompat_init()
 	su_kps[0] = init_kprobe(SYS_EXECVE_SYMBOL, execve_handler_pre);
 	su_kps[1] = init_kprobe(SYS_FACCESSAT_SYMBOL, faccessat_handler_pre);
 	su_kps[2] = init_kprobe(SYS_NEWFSTATAT_SYMBOL, newfstatat_handler_pre);
-#ifdef MODULE
 	su_kps[3] = init_kprobe("pts_unix98_lookup", pts_unix98_lookup_pre);
-#endif
 #else
-	ksu_sucompat_non_kp = true;
+	ksu_sucompat_hook_state = true;
  	pr_info("ksu_sucompat_init: hooks enabled: execve/execveat_su, faccessat, stat\n");
 #endif
 }
@@ -336,7 +319,7 @@ void ksu_sucompat_exit()
 		destroy_kprobe(&su_kps[i]);
 	}
 #else
-	ksu_sucompat_non_kp = false;
+	ksu_sucompat_hook_state = false;
  	pr_info("ksu_sucompat_exit: hooks disabled: execve/execveat_su, faccessat, stat\n");
 #endif
 }