patches: Support path_umount

- xiaoleGun#142
- tiann/KernelSU@b4cfc2f
- https://kernelsu.org/guide/how-to-integrate-for-non-gki.html#how-to-backport-path-umount

patches/patches.sh

@@ -1,15 +1,16 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Patches author: weishu <[email protected]>
 # Shell authon: xiaoleGun <[email protected]>
 #               bdqllW <[email protected]>
 # Tested kernel versions: 5.4, 4.19, 4.14, 4.9
-# 20240123
+# 20240601
 
 patch_files=(
     fs/exec.c
     fs/open.c
     fs/read_write.c
     fs/stat.c
+    fs/namespace.c
     drivers/input/input.c
 )
 
@@ -23,7 +24,6 @@ for i in "${patch_files[@]}"; do
     case $i in
 
     # fs/ changes
-    ## exec.c
     fs/exec.c)
         sed -i '/static int do_execveat_common/i\#ifdef CONFIG_KSU\nextern bool ksu_execveat_hook __read_mostly;\nextern int ksu_handle_execveat(int *fd, struct filename **filename_ptr, void *argv,\n			void *envp, int *flags);\nextern int ksu_handle_execveat_sucompat(int *fd, struct filename **filename_ptr,\n				 void *argv, void *envp, int *flags);\n#endif' fs/exec.c
         if grep -q "return __do_execve_file(fd, filename, argv, envp, flags, NULL);" fs/exec.c; then
@@ -33,7 +33,6 @@ for i in "${patch_files[@]}"; do
         fi
         ;;
 
-    ## open.c
     fs/open.c)
         if grep -q "long do_faccessat(int dfd, const char __user \*filename, int mode)" fs/open.c; then
             sed -i '/long do_faccessat(int dfd, const char __user \*filename, int mode)/i\#ifdef CONFIG_KSU\nextern int ksu_handle_faccessat(int *dfd, const char __user **filename_user, int *mode,\n			 int *flags);\n#endif' fs/open.c
@@ -43,18 +42,16 @@ for i in "${patch_files[@]}"; do
         sed -i '/if (mode & ~S_IRWXO)/i\	#ifdef CONFIG_KSU\n	ksu_handle_faccessat(&dfd, &filename, &mode, NULL);\n	#endif\n' fs/open.c
         ;;
 
-    ## read_write.c
     fs/read_write.c)
         sed -i '/ssize_t vfs_read(struct file/i\#ifdef CONFIG_KSU\nextern bool ksu_vfs_read_hook __read_mostly;\nextern int ksu_handle_vfs_read(struct file **file_ptr, char __user **buf_ptr,\n		size_t *count_ptr, loff_t **pos);\n#endif' fs/read_write.c
         sed -i '/ssize_t vfs_read(struct file/,/ssize_t ret;/{/ssize_t ret;/a\
-        #ifdef CONFIG_KSU\
-        if (unlikely(ksu_vfs_read_hook))\
-            ksu_handle_vfs_read(&file, &buf, &count, &pos);\
-        #endif
+    #ifdef CONFIG_KSU\
+    if (unlikely(ksu_vfs_read_hook))\
+        ksu_handle_vfs_read(&file, &buf, &count, &pos);\
+    #endif
         }' fs/read_write.c
         ;;
 
-    ## stat.c
     fs/stat.c)
         if grep -q "int vfs_statx(int dfd, const char __user \*filename, int flags," fs/stat.c; then
             sed -i '/int vfs_statx(int dfd, const char __user \*filename, int flags,/i\#ifdef CONFIG_KSU\nextern int ksu_handle_stat(int *dfd, const char __user **filename_user, int *flags);\n#endif' fs/stat.c
@@ -65,8 +62,47 @@ for i in "${patch_files[@]}"; do
         fi
         ;;
 
+    fs/namespace.c)
+        sed -i '/int ksys_umount(char __user \*name, int flags)/i \
+#ifdef CONFIG_KSU\
+static int can_umount(const struct path *path, int flags)\
+{\
+    struct mount *mnt = real_mount(path->mnt);\
+\
+    if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))\
+        return -EINVAL;\
+    if (!may_mount())\
+        return -EPERM;\
+    if (path->dentry != path->mnt->mnt_root)\
+        return -EINVAL;\
+    if (!check_mnt(mnt))\
+        return -EINVAL;\
+    if (mnt->mnt.mnt_flags & MNT_LOCKED) /* Check optimistically */\
+        return -EINVAL;\
+    if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))\
+        return -EPERM;\
+    return 0;\
+}\
+\
+int path_umount(struct path *path, int flags)\
+{\
+    struct mount *mnt = real_mount(path->mnt);\
+    int ret;\
+\
+    ret = can_umount(path, flags);\
+    if (!ret)\
+        ret = do_umount(mnt, flags);\
+\
+    /* we must not call path_put() as that would clear mnt_expiry_mark */\
+    dput(path->dentry);\
+    mntput_no_expire(mnt);\
+    return ret;\
+}\
+#endif\
+' fs/namespace.c
+        ;;
+
     # drivers/input changes
-    ## input.c
     drivers/input/input.c)
         sed -i '/static void input_handle_event/i\#ifdef CONFIG_KSU\nextern bool ksu_input_hook __read_mostly;\nextern int ksu_handle_input_handle_event(unsigned int *type, unsigned int *code, int *value);\n#endif\n' drivers/input/input.c
         sed -i '/int disposition = input_get_disposition(dev, type, code, &value);/a\	#ifdef CONFIG_KSU\n	if (unlikely(ksu_input_hook))\n		ksu_handle_input_handle_event(&type, &code, &value);\n	#endif' drivers/input/input.c