From 23ed4384e625ac447859cad033c6522aaf9e9d47 Mon Sep 17 00:00:00 2001
From: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>
Date: Thu, 25 Sep 2025 16:13:07 +0800
Subject: [PATCH] Revert "Unmount isolated process which forks from zygote
 unconditionally (#2747)"

This reverts commit 695e749e3e99500fb0ec96f21aab5ce5f516ad79.
---
 kernel/core_hook.c | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)

diff --git a/kernel/core_hook.c b/kernel/core_hook.c
index 63c066f9..9387e994 100644
--- a/kernel/core_hook.c
+++ b/kernel/core_hook.c
@@ -66,7 +66,7 @@ static inline bool is_allow_su()
 	return ksu_is_allow_uid(current_uid().val);
 }
 
-static inline bool is_unsupported_app_uid(uid_t uid)
+static inline bool is_unsupported_uid(uid_t uid)
 {
 #define LAST_APPLICATION_UID 19999
 	uid_t appid = uid % 100000;
@@ -628,13 +628,14 @@ int ksu_handle_prctl(int option, unsigned long arg2, unsigned long arg3,
 	return 0;
 }
 
-static bool is_non_appuid(kuid_t uid)
+static bool is_appuid(kuid_t uid)
 {
 #define PER_USER_RANGE 100000
 #define FIRST_APPLICATION_UID 10000
+#define LAST_APPLICATION_UID 19999
 
 	uid_t appid = uid.val % PER_USER_RANGE;
-	return appid < FIRST_APPLICATION_UID;
+	return appid >= FIRST_APPLICATION_UID && appid <= LAST_APPLICATION_UID;
 }
 
 static bool should_umount(struct path *path)
@@ -706,25 +707,13 @@ int ksu_handle_setuid(struct cred *new, const struct cred *old)
 		return 0;
 	}
 
-	if (is_non_appuid(new_uid)) {
-#ifdef CONFIG_KSU_DEBUG
-		pr_info("handle setuid ignore non application uid: %d\n", new_uid.val);
-#endif
+	if (!is_appuid(new_uid) || is_unsupported_uid(new_uid.val)) {
+		// pr_info("handle setuid ignore non application or isolated uid: %d\n", new_uid.val);
 		return 0;
 	}
 
-	// isolated process may be directly forked from zygote, always unmount
-	if (is_unsupported_app_uid(new_uid.val)) {
-#ifdef CONFIG_KSU_DEBUG
-		pr_info("handle umount for unsupported application uid: %d\n", new_uid.val);
-#endif
-		goto do_umount;
-	}
-
 	if (ksu_is_allow_uid(new_uid.val)) {
-#ifdef CONFIG_KSU_DEBUG
-		pr_info("handle setuid ignore allowed application: %d\n", new_uid.val);
-#endif
+		// pr_info("handle setuid ignore allowed application: %d\n", new_uid.val);
 		return 0;
 	}
 
@@ -736,11 +725,11 @@ int ksu_handle_setuid(struct cred *new, const struct cred *old)
 #endif
 	}
 
-do_umount:
 	// check old process's selinux context, if it is not zygote, ignore it!
 	// because some su apps may setuid to untrusted_app but they are in global mount namespace
 	// when we umount for such process, that is a disaster!
-	if (!is_zygote(old->security)) {
+	bool is_zygote_child = is_zygote(old->security);
+	if (!is_zygote_child) {
 		pr_info("handle umount ignore non zygote child: %d\n",
 			current->pid);
 		return 0;