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package main
import (
"context"
"crypto/rand"
"encoding/binary"
"errors"
"flag"
"fmt"
"io"
"os"
"strings"
"github.com/google/subcommands"
"roseh.moe/pkg/wordlist"
)
type encCmd struct {
generatePassword bool
password string
force bool
passwordIn func() (string, error)
passwordOut io.Writer
stdin io.Reader
stdout io.Writer
}
func (*encCmd) Name() string { return "enc" }
func (*encCmd) Synopsis() string { return "encrypt" }
func (*encCmd) Usage() string {
return `usage: sym enc [OPTION]... [FILE]...
Encrypt files, or stdin if no files are provided.
One of -g or -p must be used when reading from stdin. When encrypting to
stdout, consider redirecting the result since binary output can mess up
your terminal. Example:
echo test | sym enc -p 'my super secure password' | base64
`
}
func (c *encCmd) SetFlags(fs *flag.FlagSet) {
fs.BoolVar(&c.generatePassword, "g", false, "generate a secure password automatically (password will be printed to stderr)")
fs.StringVar(&c.password, "p", "", "use the specified password; if not provided, enc will prompt for a password")
fs.BoolVar(&c.force, "f", false, "overwrite output files even if they already exist")
}
func (c *encCmd) encrypt(w io.Writer, r io.Reader, password string) error {
writer := newEncryptingWriter(w, password)
if _, err := io.Copy(writer, r); err != nil {
return err
}
return writer.close()
}
func (c *encCmd) encryptFile(fileName string, password string) (err error) {
f, err := os.Open(fileName)
if err != nil {
return err
}
defer f.Close()
fileOpts := os.O_CREATE | os.O_WRONLY
if c.force {
fileOpts |= os.O_TRUNC
} else {
fileOpts |= os.O_EXCL
}
fOut, err := os.OpenFile(fileName+".enc", fileOpts, 0644)
if err != nil {
if errors.Is(err, os.ErrExist) {
return fmt.Errorf("output file %q exists (use -f to overwrite)", fileName+".enc")
}
return err
}
defer func() {
fOut.Close()
if err != nil {
os.Remove(fOut.Name())
}
}()
if err = c.encrypt(fOut, f, password); err != nil {
return fmt.Errorf("encrypt %q: %s", fileName, err)
}
return fOut.Close()
}
func (c *encCmd) readPassword() (string, error) {
fmt.Fprint(os.Stderr, "Enter password: ")
password, err := c.passwordIn()
fmt.Fprintln(os.Stderr)
if err != nil {
return "", err
}
if password == "" {
return "", usageErr("password cannot be empty")
}
fmt.Fprint(os.Stderr, "Repeat password: ")
pwConfirm, err := c.passwordIn()
fmt.Fprintln(os.Stderr)
if err != nil {
return "", err
}
if pwConfirm != password {
return "", usageErr("passwords do not match")
}
return password, nil
}
func (c *encCmd) run(args ...string) error {
if c.generatePassword && c.password != "" {
return usageErr("-g and -p cannot be used together")
}
if len(args) == 0 && !c.generatePassword && c.password == "" {
return usageErr("must use -g or -p when reading from stdin")
}
var password string
if c.password != "" {
password = c.password
} else if c.generatePassword {
const nWords = 10
buf := make([]byte, 2*nWords)
rand.Read(buf)
words := make([]string, nWords)
for i := range words {
words[i] = wordlist.Words[binary.NativeEndian.Uint16(buf[2*i:])&0x1fff]
}
password = strings.Join(words, " ")
fmt.Fprint(os.Stderr, "Your password: ")
fmt.Fprint(c.passwordOut, password)
fmt.Fprintln(os.Stderr)
} else {
var err error
if password, err = c.readPassword(); err != nil {
return err
}
}
if len(args) == 0 {
return c.encrypt(c.stdout, c.stdin, password)
}
for _, fileName := range args {
if err := c.encryptFile(fileName, password); err != nil {
return err
}
}
return nil
}
func (c *encCmd) Execute(ctx context.Context, f *flag.FlagSet, _ ...any) subcommands.ExitStatus {
if err := c.run(f.Args()...); err != nil {
fmt.Fprintf(os.Stderr, "sym: %s\n", err)
if errors.Is(err, errUsage) {
return subcommands.ExitUsageError
}
return subcommands.ExitFailure
}
return subcommands.ExitSuccess
}
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