152 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			152 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| /*
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|    Copyright The containerd Authors.
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| 
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|    Licensed under the Apache License, Version 2.0 (the "License");
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|    you may not use this file except in compliance with the License.
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|    You may obtain a copy of the License at
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| 
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|        http://www.apache.org/licenses/LICENSE-2.0
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| 
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|    Unless required by applicable law or agreed to in writing, software
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|    distributed under the License is distributed on an "AS IS" BASIS,
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|    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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|    See the License for the specific language governing permissions and
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|    limitations under the License.
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| */
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| 
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| package sys
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| 
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| import (
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| 	"os"
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| 	"regexp"
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| 	"syscall"
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| 	"unsafe"
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| 
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| 	"golang.org/x/sys/windows"
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| )
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| 
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| // SddlAdministratorsLocalSystem is local administrators plus NT AUTHORITY\System.
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| const SddlAdministratorsLocalSystem = "D:P(A;OICI;GA;;;BA)(A;OICI;GA;;;SY)"
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| 
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| // volumePath is a regular expression to check if a path is a Windows
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| // volume path (e.g., "\\?\Volume{4c1b02c1-d990-11dc-99ae-806e6f6e6963}"
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| // or "\\?\Volume{4c1b02c1-d990-11dc-99ae-806e6f6e6963}\").
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| var volumePath = regexp.MustCompile(`^\\\\\?\\Volume{[a-z0-9-]+}\\?$`)
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| 
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| // MkdirAllWithACL is a custom version of os.MkdirAll modified for use on Windows
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| // so that it is both volume path aware, and to create a directory
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| // an appropriate SDDL defined ACL for Builtin Administrators and Local System.
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| func MkdirAllWithACL(path string, _ os.FileMode) error {
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| 	sa, err := makeSecurityAttributes(SddlAdministratorsLocalSystem)
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| 	if err != nil {
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| 		return &os.PathError{Op: "mkdirall", Path: path, Err: err}
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| 	}
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| 	return mkdirall(path, sa)
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| }
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| 
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| // MkdirAll is a custom version of os.MkdirAll that is volume path aware for
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| // Windows. It can be used as a drop-in replacement for os.MkdirAll.
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| func MkdirAll(path string, _ os.FileMode) error {
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| 	return mkdirall(path, nil)
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| }
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| 
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| // mkdirall is a custom version of os.MkdirAll modified for use on Windows
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| // so that it is both volume path aware, and can create a directory with
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| // a DACL.
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| func mkdirall(path string, perm *windows.SecurityAttributes) error {
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| 	if volumePath.MatchString(path) {
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| 		return nil
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| 	}
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| 
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| 	// The rest of this method is largely copied from os.MkdirAll and should be kept
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| 	// as-is to ensure compatibility.
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| 
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| 	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
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| 	dir, err := os.Stat(path)
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| 	if err == nil {
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| 		if dir.IsDir() {
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| 			return nil
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| 		}
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| 		return &os.PathError{Op: "mkdir", Path: path, Err: syscall.ENOTDIR}
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| 	}
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| 
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| 	// Slow path: make sure parent exists and then call Mkdir for path.
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| 	i := len(path)
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| 	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
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| 		i--
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| 	}
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| 
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| 	j := i
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| 	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
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| 		j--
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| 	}
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| 
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| 	if j > 1 {
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| 		// Create parent.
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| 		err = mkdirall(fixRootDirectory(path[:j-1]), perm)
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| 		if err != nil {
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| 			return err
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| 		}
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| 	}
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| 
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| 	// Parent now exists; invoke Mkdir and use its result.
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| 	err = mkdirWithACL(path, perm)
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| 	if err != nil {
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| 		// Handle arguments like "foo/." by
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| 		// double-checking that directory doesn't exist.
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| 		dir, err1 := os.Lstat(path)
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| 		if err1 == nil && dir.IsDir() {
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| 			return nil
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| 		}
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| 		return err
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| 	}
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| 	return nil
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| }
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| 
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| // mkdirWithACL creates a new directory. If there is an error, it will be of
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| // type *PathError. .
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| //
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| // This is a modified and combined version of os.Mkdir and windows.Mkdir
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| // in golang to cater for creating a directory am ACL permitting full
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| // access, with inheritance, to any subfolder/file for Built-in Administrators
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| // and Local System.
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| func mkdirWithACL(name string, sa *windows.SecurityAttributes) error {
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| 	if sa == nil {
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| 		return os.Mkdir(name, 0)
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| 	}
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| 
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| 	namep, err := windows.UTF16PtrFromString(name)
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| 	if err != nil {
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| 		return &os.PathError{Op: "mkdir", Path: name, Err: err}
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| 	}
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| 
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| 	err = windows.CreateDirectory(namep, sa)
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| 	if err != nil {
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| 		return &os.PathError{Op: "mkdir", Path: name, Err: err}
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| 	}
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| 	return nil
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| }
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| 
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| // fixRootDirectory fixes a reference to a drive's root directory to
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| // have the required trailing slash.
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| func fixRootDirectory(p string) string {
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| 	if len(p) == len(`\\?\c:`) {
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| 		if os.IsPathSeparator(p[0]) && os.IsPathSeparator(p[1]) && p[2] == '?' && os.IsPathSeparator(p[3]) && p[5] == ':' {
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| 			return p + `\`
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| 		}
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| 	}
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| 	return p
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| }
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| 
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| func makeSecurityAttributes(sddl string) (*windows.SecurityAttributes, error) {
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| 	var sa windows.SecurityAttributes
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| 	sa.Length = uint32(unsafe.Sizeof(sa))
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| 	sa.InheritHandle = 1
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| 	var err error
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| 	sa.SecurityDescriptor, err = windows.SecurityDescriptorFromString(sddl)
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| 	if err != nil {
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| 		return nil, err
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| 	}
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| 	return &sa, nil
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| }
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