/
gpg.go
84 lines (71 loc) · 2.57 KB
/
gpg.go
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package gpg
import (
"bytes"
"fmt"
"io"
"os"
"strings"
"github.com/ProtonMail/go-crypto/openpgp"
"github.com/crc-org/crc/v2/pkg/crc/constants"
"github.com/crc-org/crc/v2/pkg/crc/logging"
goOpenpgp "golang.org/x/crypto/openpgp" //nolint
goClearsign "golang.org/x/crypto/openpgp/clearsign" //nolint
)
func Verify(filePath, signatureFilePath string) error {
data, err := os.Open(filePath)
if err != nil {
return err
}
defer data.Close()
signature, err := os.Open(signatureFilePath)
if err != nil {
return err
}
defer signature.Close()
keyring, err := openpgp.ReadArmoredKeyRing(bytes.NewBufferString(constants.CrcOrgPublicKey))
if err != nil {
return fmt.Errorf("failed to parse public key: %s", err)
}
if _, err = openpgp.CheckArmoredDetachedSignature(keyring, data, signature, nil); err != nil {
return fmt.Errorf("failed to check signature: %s", err)
}
return nil
}
func GetVerifiedClearsignedMsgV3(pubkey, clearSignedMsg string) (string, error) {
k, err := goOpenpgp.ReadArmoredKeyRing(bytes.NewBufferString(pubkey))
if err != nil {
return "", fmt.Errorf("Unable to read pubkey: %w", err)
}
block, rest := goClearsign.Decode([]byte(clearSignedMsg))
if len(rest) != 0 {
return "", fmt.Errorf("Error decoding clear signed message")
}
sig, err := io.ReadAll(block.ArmoredSignature.Body)
if err != nil {
return "", fmt.Errorf("Error reading signature: %w", err)
}
// CheckDetachedSignature method expects the clear text msg
// in the canonical format as defined in the pgp spec which
// says that each line of the text needs to end with \r\n
clearTextMsg := make([]byte, len(block.Bytes))
copy(clearTextMsg, block.Bytes)
canonicalizedMsgText := canonicalize(trimEachLine(string(clearTextMsg)))
id, err := goOpenpgp.CheckDetachedSignature(k, bytes.NewBufferString(canonicalizedMsgText), bytes.NewBuffer(sig))
if err != nil {
return "", fmt.Errorf("Invalid signature: %w", err)
}
logging.Debugf("Got valid signature from key id: %s", id.PrimaryKey.KeyIdString())
return trimEachLine(string(clearTextMsg)), nil
}
// https://github.com/ProtonMail/gopenpgp/blob/5aebf6a366fd8b81e80c337186fdaa0793597354/internal/common.go#L10-L12
func canonicalize(text string) string {
return strings.ReplaceAll(strings.ReplaceAll(text, "\r\n", "\n"), "\n", "\r\n")
}
// https://github.com/ProtonMail/gopenpgp/blob/5aebf6a366fd8b81e80c337186fdaa0793597354/internal/common.go#L14-L22
func trimEachLine(text string) string {
lines := strings.Split(text, "\n")
for i := range lines {
lines[i] = strings.TrimRight(lines[i], " \t\r")
}
return strings.Join(lines, "\n")
}