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mirror of https://github.com/docker/docker-credential-helpers.git synced 2026-06-13 16:01:28 +05:30

remove uses of golang.org/x/sys/execabs

the "golang.org/x/sys/execabs" package was introduced to address a security
issue on Windows, and changing the default behavior of os/exec was considered
a breaking change. go1.19 applied the behavior that was previously implemented
in the execabs package;

from the release notes: https://go.dev/doc/go1.19#os-exec-path

> Command and LookPath no longer allow results from a PATH search to be found
> relative to the current directory. This removes a common source of security
> problems but may also break existing programs that depend on using, say,
> exec.Command("prog") to run a binary named prog (or, on Windows, prog.exe)
> in the current directory. See the os/exec package documentation for information
> about how best to update such programs.
>
> On Windows, Command and LookPath now respect the NoDefaultCurrentDirectoryInExePath
> environment variable, making it possible to disable the default implicit search
> of “.” in PATH lookups on Windows systems.

With those changes, we no longer need to use the execabs package, and we can
switch back to os/exec.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This commit is contained in:
Sebastiaan van Stijn
2023-05-26 02:08:00 +02:00
parent da93839996
commit 37c4a6b158
6 changed files with 5 additions and 149 deletions
-102
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@@ -1,102 +0,0 @@
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package execabs is a drop-in replacement for os/exec
// that requires PATH lookups to find absolute paths.
// That is, execabs.Command("cmd") runs the same PATH lookup
// as exec.Command("cmd"), but if the result is a path
// which is relative, the Run and Start methods will report
// an error instead of running the executable.
//
// See https://blog.golang.org/path-security for more information
// about when it may be necessary or appropriate to use this package.
package execabs
import (
"context"
"fmt"
"os/exec"
"path/filepath"
"reflect"
"unsafe"
)
// ErrNotFound is the error resulting if a path search failed to find an executable file.
// It is an alias for exec.ErrNotFound.
var ErrNotFound = exec.ErrNotFound
// Cmd represents an external command being prepared or run.
// It is an alias for exec.Cmd.
type Cmd = exec.Cmd
// Error is returned by LookPath when it fails to classify a file as an executable.
// It is an alias for exec.Error.
type Error = exec.Error
// An ExitError reports an unsuccessful exit by a command.
// It is an alias for exec.ExitError.
type ExitError = exec.ExitError
func relError(file, path string) error {
return fmt.Errorf("%s resolves to executable in current directory (.%c%s)", file, filepath.Separator, path)
}
// LookPath searches for an executable named file in the directories
// named by the PATH environment variable. If file contains a slash,
// it is tried directly and the PATH is not consulted. The result will be
// an absolute path.
//
// LookPath differs from exec.LookPath in its handling of PATH lookups,
// which are used for file names without slashes. If exec.LookPath's
// PATH lookup would have returned an executable from the current directory,
// LookPath instead returns an error.
func LookPath(file string) (string, error) {
path, err := exec.LookPath(file)
if err != nil && !isGo119ErrDot(err) {
return "", err
}
if filepath.Base(file) == file && !filepath.IsAbs(path) {
return "", relError(file, path)
}
return path, nil
}
func fixCmd(name string, cmd *exec.Cmd) {
if filepath.Base(name) == name && !filepath.IsAbs(cmd.Path) && !isGo119ErrFieldSet(cmd) {
// exec.Command was called with a bare binary name and
// exec.LookPath returned a path which is not absolute.
// Set cmd.lookPathErr and clear cmd.Path so that it
// cannot be run.
lookPathErr := (*error)(unsafe.Pointer(reflect.ValueOf(cmd).Elem().FieldByName("lookPathErr").Addr().Pointer()))
if *lookPathErr == nil {
*lookPathErr = relError(name, cmd.Path)
}
cmd.Path = ""
}
}
// CommandContext is like Command but includes a context.
//
// The provided context is used to kill the process (by calling os.Process.Kill)
// if the context becomes done before the command completes on its own.
func CommandContext(ctx context.Context, name string, arg ...string) *exec.Cmd {
cmd := exec.CommandContext(ctx, name, arg...)
fixCmd(name, cmd)
return cmd
}
// Command returns the Cmd struct to execute the named program with the given arguments.
// See exec.Command for most details.
//
// Command differs from exec.Command in its handling of PATH lookups,
// which are used when the program name contains no slashes.
// If exec.Command would have returned an exec.Cmd configured to run an
// executable from the current directory, Command instead
// returns an exec.Cmd that will return an error from Start or Run.
func Command(name string, arg ...string) *exec.Cmd {
cmd := exec.Command(name, arg...)
fixCmd(name, cmd)
return cmd
}
-18
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@@ -1,18 +0,0 @@
// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build !go1.19
// +build !go1.19
package execabs
import "os/exec"
func isGo119ErrDot(err error) bool {
return false
}
func isGo119ErrFieldSet(cmd *exec.Cmd) bool {
return false
}
-21
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@@ -1,21 +0,0 @@
// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build go1.19
// +build go1.19
package execabs
import (
"errors"
"os/exec"
)
func isGo119ErrDot(err error) bool {
return errors.Is(err, exec.ErrDot)
}
func isGo119ErrFieldSet(cmd *exec.Cmd) bool {
return cmd.Err != nil
}
-1
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@@ -3,6 +3,5 @@
github.com/danieljoos/wincred
# golang.org/x/sys v0.7.0
## explicit; go 1.17
golang.org/x/sys/execabs
golang.org/x/sys/internal/unsafeheader
golang.org/x/sys/windows