mirror of
https://github.com/containers/skopeo.git
synced 2025-09-21 18:09:08 +00:00
Add support for Fulcio and Rekor, and --sign-by-sigstore=param-file
(skopeo copy) and (skopeo sync) now support --sign-by-sigstore=param-file, using the containers-sigstore-signing-params.yaml(5) file format. That notably adds support for Fulcio and Rekor signing. Signed-off-by: Miloslav Trmač <mitr@redhat.com>
This commit is contained in:
Miloslav Trmač
678
vendor/golang.org/x/mod/sumdb/note/note.go
generated
vendored
Normal file
678
vendor/golang.org/x/mod/sumdb/note/note.go
generated
vendored
Normal file
@@ -0,0 +1,678 @@
|
||||
// Copyright 2019 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 note defines the notes signed by the Go module database server.
|
||||
//
|
||||
// A note is text signed by one or more server keys.
|
||||
// The text should be ignored unless the note is signed by
|
||||
// a trusted server key and the signature has been verified
|
||||
// using the server's public key.
|
||||
//
|
||||
// A server's public key is identified by a name, typically the "host[/path]"
|
||||
// giving the base URL of the server's transparency log.
|
||||
// The syntactic restrictions on a name are that it be non-empty,
|
||||
// well-formed UTF-8 containing neither Unicode spaces nor plus (U+002B).
|
||||
//
|
||||
// A Go module database server signs texts using public key cryptography.
|
||||
// A given server may have multiple public keys, each
|
||||
// identified by a 32-bit hash of the public key.
|
||||
//
|
||||
// # Verifying Notes
|
||||
//
|
||||
// A Verifier allows verification of signatures by one server public key.
|
||||
// It can report the name of the server and the uint32 hash of the key,
|
||||
// and it can verify a purported signature by that key.
|
||||
//
|
||||
// The standard implementation of a Verifier is constructed
|
||||
// by NewVerifier starting from a verifier key, which is a
|
||||
// plain text string of the form "<name>+<hash>+<keydata>".
|
||||
//
|
||||
// A Verifiers allows looking up a Verifier by the combination
|
||||
// of server name and key hash.
|
||||
//
|
||||
// The standard implementation of a Verifiers is constructed
|
||||
// by VerifierList from a list of known verifiers.
|
||||
//
|
||||
// A Note represents a text with one or more signatures.
|
||||
// An implementation can reject a note with too many signatures
|
||||
// (for example, more than 100 signatures).
|
||||
//
|
||||
// A Signature represents a signature on a note, verified or not.
|
||||
//
|
||||
// The Open function takes as input a signed message
|
||||
// and a set of known verifiers. It decodes and verifies
|
||||
// the message signatures and returns a Note structure
|
||||
// containing the message text and (verified or unverified) signatures.
|
||||
//
|
||||
// # Signing Notes
|
||||
//
|
||||
// A Signer allows signing a text with a given key.
|
||||
// It can report the name of the server and the hash of the key
|
||||
// and can sign a raw text using that key.
|
||||
//
|
||||
// The standard implementation of a Signer is constructed
|
||||
// by NewSigner starting from an encoded signer key, which is a
|
||||
// plain text string of the form "PRIVATE+KEY+<name>+<hash>+<keydata>".
|
||||
// Anyone with an encoded signer key can sign messages using that key,
|
||||
// so it must be kept secret. The encoding begins with the literal text
|
||||
// "PRIVATE+KEY" to avoid confusion with the public server key.
|
||||
//
|
||||
// The Sign function takes as input a Note and a list of Signers
|
||||
// and returns an encoded, signed message.
|
||||
//
|
||||
// # Signed Note Format
|
||||
//
|
||||
// A signed note consists of a text ending in newline (U+000A),
|
||||
// followed by a blank line (only a newline),
|
||||
// followed by one or more signature lines of this form:
|
||||
// em dash (U+2014), space (U+0020),
|
||||
// server name, space, base64-encoded signature, newline.
|
||||
//
|
||||
// Signed notes must be valid UTF-8 and must not contain any
|
||||
// ASCII control characters (those below U+0020) other than newline.
|
||||
//
|
||||
// A signature is a base64 encoding of 4+n bytes.
|
||||
//
|
||||
// The first four bytes in the signature are the uint32 key hash
|
||||
// stored in big-endian order.
|
||||
//
|
||||
// The remaining n bytes are the result of using the specified key
|
||||
// to sign the note text (including the final newline but not the
|
||||
// separating blank line).
|
||||
//
|
||||
// # Generating Keys
|
||||
//
|
||||
// There is only one key type, Ed25519 with algorithm identifier 1.
|
||||
// New key types may be introduced in the future as needed,
|
||||
// although doing so will require deploying the new algorithms to all clients
|
||||
// before starting to depend on them for signatures.
|
||||
//
|
||||
// The GenerateKey function generates and returns a new signer
|
||||
// and corresponding verifier.
|
||||
//
|
||||
// # Example
|
||||
//
|
||||
// Here is a well-formed signed note:
|
||||
//
|
||||
// If you think cryptography is the answer to your problem,
|
||||
// then you don't know what your problem is.
|
||||
//
|
||||
// — PeterNeumann x08go/ZJkuBS9UG/SffcvIAQxVBtiFupLLr8pAcElZInNIuGUgYN1FFYC2pZSNXgKvqfqdngotpRZb6KE6RyyBwJnAM=
|
||||
//
|
||||
// It can be constructed and displayed using:
|
||||
//
|
||||
// skey := "PRIVATE+KEY+PeterNeumann+c74f20a3+AYEKFALVFGyNhPJEMzD1QIDr+Y7hfZx09iUvxdXHKDFz"
|
||||
// text := "If you think cryptography is the answer to your problem,\n" +
|
||||
// "then you don't know what your problem is.\n"
|
||||
//
|
||||
// signer, err := note.NewSigner(skey)
|
||||
// if err != nil {
|
||||
// log.Fatal(err)
|
||||
// }
|
||||
//
|
||||
// msg, err := note.Sign(¬e.Note{Text: text}, signer)
|
||||
// if err != nil {
|
||||
// log.Fatal(err)
|
||||
// }
|
||||
// os.Stdout.Write(msg)
|
||||
//
|
||||
// The note's text is two lines, including the final newline,
|
||||
// and the text is purportedly signed by a server named
|
||||
// "PeterNeumann". (Although server names are canonically
|
||||
// base URLs, the only syntactic requirement is that they
|
||||
// not contain spaces or newlines).
|
||||
//
|
||||
// If Open is given access to a Verifiers including the
|
||||
// Verifier for this key, then it will succeed at verifiying
|
||||
// the encoded message and returning the parsed Note:
|
||||
//
|
||||
// vkey := "PeterNeumann+c74f20a3+ARpc2QcUPDhMQegwxbzhKqiBfsVkmqq/LDE4izWy10TW"
|
||||
// msg := []byte("If you think cryptography is the answer to your problem,\n" +
|
||||
// "then you don't know what your problem is.\n" +
|
||||
// "\n" +
|
||||
// "— PeterNeumann x08go/ZJkuBS9UG/SffcvIAQxVBtiFupLLr8pAcElZInNIuGUgYN1FFYC2pZSNXgKvqfqdngotpRZb6KE6RyyBwJnAM=\n")
|
||||
//
|
||||
// verifier, err := note.NewVerifier(vkey)
|
||||
// if err != nil {
|
||||
// log.Fatal(err)
|
||||
// }
|
||||
// verifiers := note.VerifierList(verifier)
|
||||
//
|
||||
// n, err := note.Open([]byte(msg), verifiers)
|
||||
// if err != nil {
|
||||
// log.Fatal(err)
|
||||
// }
|
||||
// fmt.Printf("%s (%08x):\n%s", n.Sigs[0].Name, n.Sigs[0].Hash, n.Text)
|
||||
//
|
||||
// You can add your own signature to this message by re-signing the note:
|
||||
//
|
||||
// skey, vkey, err := note.GenerateKey(rand.Reader, "EnochRoot")
|
||||
// if err != nil {
|
||||
// log.Fatal(err)
|
||||
// }
|
||||
// _ = vkey // give to verifiers
|
||||
//
|
||||
// me, err := note.NewSigner(skey)
|
||||
// if err != nil {
|
||||
// log.Fatal(err)
|
||||
// }
|
||||
//
|
||||
// msg, err := note.Sign(n, me)
|
||||
// if err != nil {
|
||||
// log.Fatal(err)
|
||||
// }
|
||||
// os.Stdout.Write(msg)
|
||||
//
|
||||
// This will print a doubly-signed message, like:
|
||||
//
|
||||
// If you think cryptography is the answer to your problem,
|
||||
// then you don't know what your problem is.
|
||||
//
|
||||
// — PeterNeumann x08go/ZJkuBS9UG/SffcvIAQxVBtiFupLLr8pAcElZInNIuGUgYN1FFYC2pZSNXgKvqfqdngotpRZb6KE6RyyBwJnAM=
|
||||
// — EnochRoot rwz+eBzmZa0SO3NbfRGzPCpDckykFXSdeX+MNtCOXm2/5n2tiOHp+vAF1aGrQ5ovTG01oOTGwnWLox33WWd1RvMc+QQ=
|
||||
package note
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"crypto/ed25519"
|
||||
"crypto/sha256"
|
||||
"encoding/base64"
|
||||
"encoding/binary"
|
||||
"errors"
|
||||
"fmt"
|
||||
"io"
|
||||
"strconv"
|
||||
"strings"
|
||||
"unicode"
|
||||
"unicode/utf8"
|
||||
)
|
||||
|
||||
// A Verifier verifies messages signed with a specific key.
|
||||
type Verifier interface {
|
||||
// Name returns the server name associated with the key.
|
||||
Name() string
|
||||
|
||||
// KeyHash returns the key hash.
|
||||
KeyHash() uint32
|
||||
|
||||
// Verify reports whether sig is a valid signature of msg.
|
||||
Verify(msg, sig []byte) bool
|
||||
}
|
||||
|
||||
// A Signer signs messages using a specific key.
|
||||
type Signer interface {
|
||||
// Name returns the server name associated with the key.
|
||||
Name() string
|
||||
|
||||
// KeyHash returns the key hash.
|
||||
KeyHash() uint32
|
||||
|
||||
// Sign returns a signature for the given message.
|
||||
Sign(msg []byte) ([]byte, error)
|
||||
}
|
||||
|
||||
// keyHash computes the key hash for the given server name and encoded public key.
|
||||
func keyHash(name string, key []byte) uint32 {
|
||||
h := sha256.New()
|
||||
h.Write([]byte(name))
|
||||
h.Write([]byte("\n"))
|
||||
h.Write(key)
|
||||
sum := h.Sum(nil)
|
||||
return binary.BigEndian.Uint32(sum)
|
||||
}
|
||||
|
||||
var (
|
||||
errVerifierID = errors.New("malformed verifier id")
|
||||
errVerifierAlg = errors.New("unknown verifier algorithm")
|
||||
errVerifierHash = errors.New("invalid verifier hash")
|
||||
)
|
||||
|
||||
const (
|
||||
algEd25519 = 1
|
||||
)
|
||||
|
||||
// isValidName reports whether name is valid.
|
||||
// It must be non-empty and not have any Unicode spaces or pluses.
|
||||
func isValidName(name string) bool {
|
||||
return name != "" && utf8.ValidString(name) && strings.IndexFunc(name, unicode.IsSpace) < 0 && !strings.Contains(name, "+")
|
||||
}
|
||||
|
||||
// NewVerifier construct a new Verifier from an encoded verifier key.
|
||||
func NewVerifier(vkey string) (Verifier, error) {
|
||||
name, vkey := chop(vkey, "+")
|
||||
hash16, key64 := chop(vkey, "+")
|
||||
hash, err1 := strconv.ParseUint(hash16, 16, 32)
|
||||
key, err2 := base64.StdEncoding.DecodeString(key64)
|
||||
if len(hash16) != 8 || err1 != nil || err2 != nil || !isValidName(name) || len(key) == 0 {
|
||||
return nil, errVerifierID
|
||||
}
|
||||
if uint32(hash) != keyHash(name, key) {
|
||||
return nil, errVerifierHash
|
||||
}
|
||||
|
||||
v := &verifier{
|
||||
name: name,
|
||||
hash: uint32(hash),
|
||||
}
|
||||
|
||||
alg, key := key[0], key[1:]
|
||||
switch alg {
|
||||
default:
|
||||
return nil, errVerifierAlg
|
||||
|
||||
case algEd25519:
|
||||
if len(key) != 32 {
|
||||
return nil, errVerifierID
|
||||
}
|
||||
v.verify = func(msg, sig []byte) bool {
|
||||
return ed25519.Verify(key, msg, sig)
|
||||
}
|
||||
}
|
||||
|
||||
return v, nil
|
||||
}
|
||||
|
||||
// chop chops s at the first instance of sep, if any,
|
||||
// and returns the text before and after sep.
|
||||
// If sep is not present, chop returns before is s and after is empty.
|
||||
func chop(s, sep string) (before, after string) {
|
||||
i := strings.Index(s, sep)
|
||||
if i < 0 {
|
||||
return s, ""
|
||||
}
|
||||
return s[:i], s[i+len(sep):]
|
||||
}
|
||||
|
||||
// verifier is a trivial Verifier implementation.
|
||||
type verifier struct {
|
||||
name string
|
||||
hash uint32
|
||||
verify func([]byte, []byte) bool
|
||||
}
|
||||
|
||||
func (v *verifier) Name() string { return v.name }
|
||||
func (v *verifier) KeyHash() uint32 { return v.hash }
|
||||
func (v *verifier) Verify(msg, sig []byte) bool { return v.verify(msg, sig) }
|
||||
|
||||
// NewSigner constructs a new Signer from an encoded signer key.
|
||||
func NewSigner(skey string) (Signer, error) {
|
||||
priv1, skey := chop(skey, "+")
|
||||
priv2, skey := chop(skey, "+")
|
||||
name, skey := chop(skey, "+")
|
||||
hash16, key64 := chop(skey, "+")
|
||||
hash, err1 := strconv.ParseUint(hash16, 16, 32)
|
||||
key, err2 := base64.StdEncoding.DecodeString(key64)
|
||||
if priv1 != "PRIVATE" || priv2 != "KEY" || len(hash16) != 8 || err1 != nil || err2 != nil || !isValidName(name) || len(key) == 0 {
|
||||
return nil, errSignerID
|
||||
}
|
||||
|
||||
// Note: hash is the hash of the public key and we have the private key.
|
||||
// Must verify hash after deriving public key.
|
||||
|
||||
s := &signer{
|
||||
name: name,
|
||||
hash: uint32(hash),
|
||||
}
|
||||
|
||||
var pubkey []byte
|
||||
|
||||
alg, key := key[0], key[1:]
|
||||
switch alg {
|
||||
default:
|
||||
return nil, errSignerAlg
|
||||
|
||||
case algEd25519:
|
||||
if len(key) != 32 {
|
||||
return nil, errSignerID
|
||||
}
|
||||
key = ed25519.NewKeyFromSeed(key)
|
||||
pubkey = append([]byte{algEd25519}, key[32:]...)
|
||||
s.sign = func(msg []byte) ([]byte, error) {
|
||||
return ed25519.Sign(key, msg), nil
|
||||
}
|
||||
}
|
||||
|
||||
if uint32(hash) != keyHash(name, pubkey) {
|
||||
return nil, errSignerHash
|
||||
}
|
||||
|
||||
return s, nil
|
||||
}
|
||||
|
||||
var (
|
||||
errSignerID = errors.New("malformed verifier id")
|
||||
errSignerAlg = errors.New("unknown verifier algorithm")
|
||||
errSignerHash = errors.New("invalid verifier hash")
|
||||
)
|
||||
|
||||
// signer is a trivial Signer implementation.
|
||||
type signer struct {
|
||||
name string
|
||||
hash uint32
|
||||
sign func([]byte) ([]byte, error)
|
||||
}
|
||||
|
||||
func (s *signer) Name() string { return s.name }
|
||||
func (s *signer) KeyHash() uint32 { return s.hash }
|
||||
func (s *signer) Sign(msg []byte) ([]byte, error) { return s.sign(msg) }
|
||||
|
||||
// GenerateKey generates a signer and verifier key pair for a named server.
|
||||
// The signer key skey is private and must be kept secret.
|
||||
func GenerateKey(rand io.Reader, name string) (skey, vkey string, err error) {
|
||||
pub, priv, err := ed25519.GenerateKey(rand)
|
||||
if err != nil {
|
||||
return "", "", err
|
||||
}
|
||||
pubkey := append([]byte{algEd25519}, pub...)
|
||||
privkey := append([]byte{algEd25519}, priv.Seed()...)
|
||||
h := keyHash(name, pubkey)
|
||||
|
||||
skey = fmt.Sprintf("PRIVATE+KEY+%s+%08x+%s", name, h, base64.StdEncoding.EncodeToString(privkey))
|
||||
vkey = fmt.Sprintf("%s+%08x+%s", name, h, base64.StdEncoding.EncodeToString(pubkey))
|
||||
return skey, vkey, nil
|
||||
}
|
||||
|
||||
// NewEd25519VerifierKey returns an encoded verifier key using the given name
|
||||
// and Ed25519 public key.
|
||||
func NewEd25519VerifierKey(name string, key ed25519.PublicKey) (string, error) {
|
||||
if len(key) != ed25519.PublicKeySize {
|
||||
return "", fmt.Errorf("invalid public key size %d, expected %d", len(key), ed25519.PublicKeySize)
|
||||
}
|
||||
|
||||
pubkey := append([]byte{algEd25519}, key...)
|
||||
hash := keyHash(name, pubkey)
|
||||
|
||||
b64Key := base64.StdEncoding.EncodeToString(pubkey)
|
||||
return fmt.Sprintf("%s+%08x+%s", name, hash, b64Key), nil
|
||||
}
|
||||
|
||||
// A Verifiers is a collection of known verifier keys.
|
||||
type Verifiers interface {
|
||||
// Verifier returns the Verifier associated with the key
|
||||
// identified by the name and hash.
|
||||
// If the name, hash pair is unknown, Verifier should return
|
||||
// an UnknownVerifierError.
|
||||
Verifier(name string, hash uint32) (Verifier, error)
|
||||
}
|
||||
|
||||
// An UnknownVerifierError indicates that the given key is not known.
|
||||
// The Open function records signatures without associated verifiers as
|
||||
// unverified signatures.
|
||||
type UnknownVerifierError struct {
|
||||
Name string
|
||||
KeyHash uint32
|
||||
}
|
||||
|
||||
func (e *UnknownVerifierError) Error() string {
|
||||
return fmt.Sprintf("unknown key %s+%08x", e.Name, e.KeyHash)
|
||||
}
|
||||
|
||||
// An ambiguousVerifierError indicates that the given name and hash
|
||||
// match multiple keys passed to VerifierList.
|
||||
// (If this happens, some malicious actor has taken control of the
|
||||
// verifier list, at which point we may as well give up entirely,
|
||||
// but we diagnose the problem instead.)
|
||||
type ambiguousVerifierError struct {
|
||||
name string
|
||||
hash uint32
|
||||
}
|
||||
|
||||
func (e *ambiguousVerifierError) Error() string {
|
||||
return fmt.Sprintf("ambiguous key %s+%08x", e.name, e.hash)
|
||||
}
|
||||
|
||||
// VerifierList returns a Verifiers implementation that uses the given list of verifiers.
|
||||
func VerifierList(list ...Verifier) Verifiers {
|
||||
m := make(verifierMap)
|
||||
for _, v := range list {
|
||||
k := nameHash{v.Name(), v.KeyHash()}
|
||||
m[k] = append(m[k], v)
|
||||
}
|
||||
return m
|
||||
}
|
||||
|
||||
type nameHash struct {
|
||||
name string
|
||||
hash uint32
|
||||
}
|
||||
|
||||
type verifierMap map[nameHash][]Verifier
|
||||
|
||||
func (m verifierMap) Verifier(name string, hash uint32) (Verifier, error) {
|
||||
v, ok := m[nameHash{name, hash}]
|
||||
if !ok {
|
||||
return nil, &UnknownVerifierError{name, hash}
|
||||
}
|
||||
if len(v) > 1 {
|
||||
return nil, &ambiguousVerifierError{name, hash}
|
||||
}
|
||||
return v[0], nil
|
||||
}
|
||||
|
||||
// A Note is a text and signatures.
|
||||
type Note struct {
|
||||
Text string // text of note
|
||||
Sigs []Signature // verified signatures
|
||||
UnverifiedSigs []Signature // unverified signatures
|
||||
}
|
||||
|
||||
// A Signature is a single signature found in a note.
|
||||
type Signature struct {
|
||||
// Name and Hash give the name and key hash
|
||||
// for the key that generated the signature.
|
||||
Name string
|
||||
Hash uint32
|
||||
|
||||
// Base64 records the base64-encoded signature bytes.
|
||||
Base64 string
|
||||
}
|
||||
|
||||
// An UnverifiedNoteError indicates that the note
|
||||
// successfully parsed but had no verifiable signatures.
|
||||
type UnverifiedNoteError struct {
|
||||
Note *Note
|
||||
}
|
||||
|
||||
func (e *UnverifiedNoteError) Error() string {
|
||||
return "note has no verifiable signatures"
|
||||
}
|
||||
|
||||
// An InvalidSignatureError indicates that the given key was known
|
||||
// and the associated Verifier rejected the signature.
|
||||
type InvalidSignatureError struct {
|
||||
Name string
|
||||
Hash uint32
|
||||
}
|
||||
|
||||
func (e *InvalidSignatureError) Error() string {
|
||||
return fmt.Sprintf("invalid signature for key %s+%08x", e.Name, e.Hash)
|
||||
}
|
||||
|
||||
var (
|
||||
errMalformedNote = errors.New("malformed note")
|
||||
errInvalidSigner = errors.New("invalid signer")
|
||||
errMismatchedVerifier = errors.New("verifier name or hash doesn't match signature")
|
||||
|
||||
sigSplit = []byte("\n\n")
|
||||
sigPrefix = []byte("— ")
|
||||
)
|
||||
|
||||
// Open opens and parses the message msg, checking signatures from the known verifiers.
|
||||
//
|
||||
// For each signature in the message, Open calls known.Verifier to find a verifier.
|
||||
// If known.Verifier returns a verifier and the verifier accepts the signature,
|
||||
// Open records the signature in the returned note's Sigs field.
|
||||
// If known.Verifier returns a verifier but the verifier rejects the signature,
|
||||
// Open returns an InvalidSignatureError.
|
||||
// If known.Verifier returns an UnknownVerifierError,
|
||||
// Open records the signature in the returned note's UnverifiedSigs field.
|
||||
// If known.Verifier returns any other error, Open returns that error.
|
||||
//
|
||||
// If no known verifier has signed an otherwise valid note,
|
||||
// Open returns an UnverifiedNoteError.
|
||||
// In this case, the unverified note can be fetched from inside the error.
|
||||
func Open(msg []byte, known Verifiers) (*Note, error) {
|
||||
if known == nil {
|
||||
// Treat nil Verifiers as empty list, to produce useful error instead of crash.
|
||||
known = VerifierList()
|
||||
}
|
||||
|
||||
// Must have valid UTF-8 with no non-newline ASCII control characters.
|
||||
for i := 0; i < len(msg); {
|
||||
r, size := utf8.DecodeRune(msg[i:])
|
||||
if r < 0x20 && r != '\n' || r == utf8.RuneError && size == 1 {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
i += size
|
||||
}
|
||||
|
||||
// Must end with signature block preceded by blank line.
|
||||
split := bytes.LastIndex(msg, sigSplit)
|
||||
if split < 0 {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
text, sigs := msg[:split+1], msg[split+2:]
|
||||
if len(sigs) == 0 || sigs[len(sigs)-1] != '\n' {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
|
||||
n := &Note{
|
||||
Text: string(text),
|
||||
}
|
||||
|
||||
// Parse and verify signatures.
|
||||
// Ignore duplicate signatures.
|
||||
seen := make(map[nameHash]bool)
|
||||
seenUnverified := make(map[string]bool)
|
||||
numSig := 0
|
||||
for len(sigs) > 0 {
|
||||
// Pull out next signature line.
|
||||
// We know sigs[len(sigs)-1] == '\n', so IndexByte always finds one.
|
||||
i := bytes.IndexByte(sigs, '\n')
|
||||
line := sigs[:i]
|
||||
sigs = sigs[i+1:]
|
||||
|
||||
if !bytes.HasPrefix(line, sigPrefix) {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
line = line[len(sigPrefix):]
|
||||
name, b64 := chop(string(line), " ")
|
||||
sig, err := base64.StdEncoding.DecodeString(b64)
|
||||
if err != nil || !isValidName(name) || b64 == "" || len(sig) < 5 {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
hash := binary.BigEndian.Uint32(sig[0:4])
|
||||
sig = sig[4:]
|
||||
|
||||
if numSig++; numSig > 100 {
|
||||
// Avoid spending forever parsing a note with many signatures.
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
|
||||
v, err := known.Verifier(name, hash)
|
||||
if _, ok := err.(*UnknownVerifierError); ok {
|
||||
// Drop repeated identical unverified signatures.
|
||||
if seenUnverified[string(line)] {
|
||||
continue
|
||||
}
|
||||
seenUnverified[string(line)] = true
|
||||
n.UnverifiedSigs = append(n.UnverifiedSigs, Signature{Name: name, Hash: hash, Base64: b64})
|
||||
continue
|
||||
}
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
// Check that known.Verifier returned the right verifier.
|
||||
if v.Name() != name || v.KeyHash() != hash {
|
||||
return nil, errMismatchedVerifier
|
||||
}
|
||||
|
||||
// Drop repeated signatures by a single verifier.
|
||||
if seen[nameHash{name, hash}] {
|
||||
continue
|
||||
}
|
||||
seen[nameHash{name, hash}] = true
|
||||
|
||||
ok := v.Verify(text, sig)
|
||||
if !ok {
|
||||
return nil, &InvalidSignatureError{name, hash}
|
||||
}
|
||||
|
||||
n.Sigs = append(n.Sigs, Signature{Name: name, Hash: hash, Base64: b64})
|
||||
}
|
||||
|
||||
// Parsed and verified all the signatures.
|
||||
if len(n.Sigs) == 0 {
|
||||
return nil, &UnverifiedNoteError{n}
|
||||
}
|
||||
return n, nil
|
||||
}
|
||||
|
||||
// Sign signs the note with the given signers and returns the encoded message.
|
||||
// The new signatures from signers are listed in the encoded message after
|
||||
// the existing signatures already present in n.Sigs.
|
||||
// If any signer uses the same key as an existing signature,
|
||||
// the existing signature is elided from the output.
|
||||
func Sign(n *Note, signers ...Signer) ([]byte, error) {
|
||||
var buf bytes.Buffer
|
||||
if !strings.HasSuffix(n.Text, "\n") {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
buf.WriteString(n.Text)
|
||||
|
||||
// Prepare signatures.
|
||||
var sigs bytes.Buffer
|
||||
have := make(map[nameHash]bool)
|
||||
for _, s := range signers {
|
||||
name := s.Name()
|
||||
hash := s.KeyHash()
|
||||
have[nameHash{name, hash}] = true
|
||||
if !isValidName(name) {
|
||||
return nil, errInvalidSigner
|
||||
}
|
||||
|
||||
sig, err := s.Sign(buf.Bytes()) // buf holds n.Text
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
var hbuf [4]byte
|
||||
binary.BigEndian.PutUint32(hbuf[:], hash)
|
||||
b64 := base64.StdEncoding.EncodeToString(append(hbuf[:], sig...))
|
||||
sigs.WriteString("— ")
|
||||
sigs.WriteString(name)
|
||||
sigs.WriteString(" ")
|
||||
sigs.WriteString(b64)
|
||||
sigs.WriteString("\n")
|
||||
}
|
||||
|
||||
buf.WriteString("\n")
|
||||
|
||||
// Emit existing signatures not replaced by new ones.
|
||||
for _, list := range [][]Signature{n.Sigs, n.UnverifiedSigs} {
|
||||
for _, sig := range list {
|
||||
name, hash := sig.Name, sig.Hash
|
||||
if !isValidName(name) {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
if have[nameHash{name, hash}] {
|
||||
continue
|
||||
}
|
||||
// Double-check hash against base64.
|
||||
raw, err := base64.StdEncoding.DecodeString(sig.Base64)
|
||||
if err != nil || len(raw) < 4 || binary.BigEndian.Uint32(raw) != hash {
|
||||
return nil, errMalformedNote
|
||||
}
|
||||
buf.WriteString("— ")
|
||||
buf.WriteString(sig.Name)
|
||||
buf.WriteString(" ")
|
||||
buf.WriteString(sig.Base64)
|
||||
buf.WriteString("\n")
|
||||
}
|
||||
}
|
||||
buf.Write(sigs.Bytes())
|
||||
|
||||
return buf.Bytes(), nil
|
||||
}
|
||||
Reference in New Issue
Block a user