DockerCLI/vendor/github.com/docker/notary/tuf/signed/sign.go

114 lines
3.8 KiB
Go

package signed
// The Sign function is a choke point for all code paths that do signing.
// We use this fact to do key ID translation. There are 2 types of key ID:
// - Scoped: the key ID based purely on the data that appears in the TUF
// files. This may be wrapped by a certificate that scopes the
// key to be used in a specific context.
// - Canonical: the key ID based purely on the public key bytes. This is
// used by keystores to easily identify keys that may be reused
// in many scoped locations.
// Currently these types only differ in the context of Root Keys in Notary
// for which the root key is wrapped using an x509 certificate.
import (
"crypto/rand"
"github.com/docker/notary/trustmanager"
"github.com/docker/notary/tuf/data"
"github.com/docker/notary/tuf/utils"
"github.com/sirupsen/logrus"
)
// Sign takes a data.Signed and a cryptoservice containing private keys,
// calculates and adds at least minSignature signatures using signingKeys the
// data.Signed. It will also clean up any signatures that are not in produced
// by either a signingKey or an otherWhitelistedKey.
// Note that in most cases, otherWhitelistedKeys should probably be null. They
// are for keys you don't want to sign with, but you also don't want to remove
// existing signatures by those keys. For instance, if you want to call Sign
// multiple times with different sets of signing keys without undoing removing
// signatures produced by the previous call to Sign.
func Sign(service CryptoService, s *data.Signed, signingKeys []data.PublicKey,
minSignatures int, otherWhitelistedKeys []data.PublicKey) error {
logrus.Debugf("sign called with %d/%d required keys", minSignatures, len(signingKeys))
signatures := make([]data.Signature, 0, len(s.Signatures)+1)
signingKeyIDs := make(map[string]struct{})
tufIDs := make(map[string]data.PublicKey)
privKeys := make(map[string]data.PrivateKey)
// Get all the private key objects related to the public keys
missingKeyIDs := []string{}
for _, key := range signingKeys {
canonicalID, err := utils.CanonicalKeyID(key)
tufIDs[key.ID()] = key
if err != nil {
return err
}
k, _, err := service.GetPrivateKey(canonicalID)
if err != nil {
if _, ok := err.(trustmanager.ErrKeyNotFound); ok {
missingKeyIDs = append(missingKeyIDs, canonicalID)
continue
}
return err
}
privKeys[key.ID()] = k
}
// include the list of otherWhitelistedKeys
for _, key := range otherWhitelistedKeys {
if _, ok := tufIDs[key.ID()]; !ok {
tufIDs[key.ID()] = key
}
}
// Check to ensure we have enough signing keys
if len(privKeys) < minSignatures {
return ErrInsufficientSignatures{FoundKeys: len(privKeys),
NeededKeys: minSignatures, MissingKeyIDs: missingKeyIDs}
}
emptyStruct := struct{}{}
// Do signing and generate list of signatures
for keyID, pk := range privKeys {
sig, err := pk.Sign(rand.Reader, *s.Signed, nil)
if err != nil {
logrus.Debugf("Failed to sign with key: %s. Reason: %v", keyID, err)
return err
}
signingKeyIDs[keyID] = emptyStruct
signatures = append(signatures, data.Signature{
KeyID: keyID,
Method: pk.SignatureAlgorithm(),
Signature: sig[:],
})
}
for _, sig := range s.Signatures {
if _, ok := signingKeyIDs[sig.KeyID]; ok {
// key is in the set of key IDs for which a signature has been created
continue
}
var (
k data.PublicKey
ok bool
)
if k, ok = tufIDs[sig.KeyID]; !ok {
// key is no longer a valid signing key
continue
}
if err := VerifySignature(*s.Signed, &sig, k); err != nil {
// signature is no longer valid
continue
}
// keep any signatures that still represent valid keys and are
// themselves valid
signatures = append(signatures, sig)
}
s.Signatures = signatures
return nil
}