86 lines
2.3 KiB
Go
86 lines
2.3 KiB
Go
//go:build !windows
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package safeio
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import (
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"errors"
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"os"
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"path/filepath"
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)
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func createPrivateDirectory(path string) error {
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if err := os.Mkdir(path, 0o700); err != nil {
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if errors.Is(err, os.ErrExist) {
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return os.ErrExist
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}
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return err
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}
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return ProtectPrivateDirectory(path)
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}
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// ProtectPrivateDirectory sets the private directory mode used for local authentication state.
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func ProtectPrivateDirectory(path string) error {
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if err := ValidateCanonicalPath(path); err != nil {
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return err
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}
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if err := os.Chmod(path, 0o700); err != nil {
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return ErrUnsafeFile
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}
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return ValidatePrivateDirectory(path)
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}
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// ValidatePrivateDirectory requires a canonical, non-symlinked directory with no group or world access.
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func ValidatePrivateDirectory(path string) error {
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if err := requireCanonicalDirectory(path); err != nil {
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return err
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}
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info, err := os.Lstat(path)
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if err != nil || !info.IsDir() || info.Mode()&os.ModeSymlink != 0 || !isExactPrivateMode(info.Mode(), 0o700) {
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return ErrUnsafeFile
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}
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return nil
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}
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// ProtectPrivateRegular sets the private file mode used for local authentication files.
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func ProtectPrivateRegular(path string) error {
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if err := ValidateCanonicalPath(path); err != nil {
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return err
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}
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if err := os.Chmod(path, 0o600); err != nil {
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return ErrUnsafeFile
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}
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return ValidatePrivateRegular(path)
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}
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func createCanonicalNewPrivateFile(path string, mode os.FileMode) (*os.File, error) {
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file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_EXCL, mode)
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if err != nil {
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return nil, err
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}
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if err := ProtectPrivateRegular(path); err != nil {
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_ = file.Close()
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_ = os.Remove(path)
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return nil, ErrUnsafeFile
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}
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return file, nil
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}
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// ValidatePrivateRegular requires a canonical, single-link private regular file.
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func ValidatePrivateRegular(path string) error {
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if err := ValidateCanonicalPath(path); err != nil {
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return err
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}
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if err := requireCanonicalDirectory(filepath.Dir(path)); err != nil {
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return err
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}
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info, err := os.Lstat(path)
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if err != nil || !info.Mode().IsRegular() || info.Mode()&os.ModeSymlink != 0 || !hasSingleLink(info) || !isExactPrivateMode(info.Mode(), 0o600) {
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return ErrUnsafeFile
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}
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return nil
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}
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func isExactPrivateMode(mode os.FileMode, permissions os.FileMode) bool {
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return mode.Perm() == permissions && mode&(os.ModeSetuid|os.ModeSetgid|os.ModeSticky) == 0
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}
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