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forgejo/models/gpg_key.go

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// Copyright 2017 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package models
import (
"bytes"
"container/list"
"crypto"
"encoding/base64"
"fmt"
"hash"
"io"
"strings"
"time"
"code.gitea.io/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/util"
"github.com/go-xorm/xorm"
"github.com/keybase/go-crypto/openpgp"
"github.com/keybase/go-crypto/openpgp/armor"
"github.com/keybase/go-crypto/openpgp/packet"
)
// GPGKey represents a GPG key.
type GPGKey struct {
ID int64 `xorm:"pk autoincr"`
OwnerID int64 `xorm:"INDEX NOT NULL"`
KeyID string `xorm:"INDEX CHAR(16) NOT NULL"`
PrimaryKeyID string `xorm:"CHAR(16)"`
Content string `xorm:"TEXT NOT NULL"`
CreatedUnix util.TimeStamp `xorm:"created"`
ExpiredUnix util.TimeStamp
AddedUnix util.TimeStamp
SubsKey []*GPGKey `xorm:"-"`
Emails []*EmailAddress
CanSign bool
CanEncryptComms bool
CanEncryptStorage bool
CanCertify bool
}
// BeforeInsert will be invoked by XORM before inserting a record
func (key *GPGKey) BeforeInsert() {
key.AddedUnix = util.TimeStampNow()
}
// AfterLoad is invoked from XORM after setting the values of all fields of this object.
func (key *GPGKey) AfterLoad(session *xorm.Session) {
err := session.Where("primary_key_id=?", key.KeyID).Find(&key.SubsKey)
if err != nil {
log.Error(3, "Find Sub GPGkeys[%d]: %v", key.KeyID, err)
}
}
// ListGPGKeys returns a list of public keys belongs to given user.
func ListGPGKeys(uid int64) ([]*GPGKey, error) {
keys := make([]*GPGKey, 0, 5)
return keys, x.Where("owner_id=? AND primary_key_id=''", uid).Find(&keys)
}
// GetGPGKeyByID returns public key by given ID.
func GetGPGKeyByID(keyID int64) (*GPGKey, error) {
key := new(GPGKey)
has, err := x.ID(keyID).Get(key)
if err != nil {
return nil, err
} else if !has {
return nil, ErrGPGKeyNotExist{keyID}
}
return key, nil
}
// checkArmoredGPGKeyString checks if the given key string is a valid GPG armored key.
// The function returns the actual public key on success
func checkArmoredGPGKeyString(content string) (*openpgp.Entity, error) {
list, err := openpgp.ReadArmoredKeyRing(strings.NewReader(content))
if err != nil {
return nil, ErrGPGKeyParsing{err}
}
return list[0], nil
}
//addGPGKey add key and subkeys to database
func addGPGKey(e Engine, key *GPGKey) (err error) {
// Save GPG primary key.
if _, err = e.Insert(key); err != nil {
return err
}
// Save GPG subs key.
for _, subkey := range key.SubsKey {
if err := addGPGKey(e, subkey); err != nil {
return err
}
}
return nil
}
// AddGPGKey adds new public key to database.
func AddGPGKey(ownerID int64, content string) (*GPGKey, error) {
ekey, err := checkArmoredGPGKeyString(content)
if err != nil {
return nil, err
}
// Key ID cannot be duplicated.
has, err := x.Where("key_id=?", ekey.PrimaryKey.KeyIdString()).
Get(new(GPGKey))
if err != nil {
return nil, err
} else if has {
return nil, ErrGPGKeyIDAlreadyUsed{ekey.PrimaryKey.KeyIdString()}
}
//Get DB session
sess := x.NewSession()
defer sess.Close()
if err = sess.Begin(); err != nil {
return nil, err
}
key, err := parseGPGKey(ownerID, ekey)
if err != nil {
return nil, err
}
if err = addGPGKey(sess, key); err != nil {
return nil, err
}
return key, sess.Commit()
}
//base64EncPubKey encode public kay content to base 64
func base64EncPubKey(pubkey *packet.PublicKey) (string, error) {
var w bytes.Buffer
err := pubkey.Serialize(&w)
if err != nil {
return "", err
}
return base64.StdEncoding.EncodeToString(w.Bytes()), nil
}
//parseSubGPGKey parse a sub Key
func parseSubGPGKey(ownerID int64, primaryID string, pubkey *packet.PublicKey, expiry time.Time) (*GPGKey, error) {
content, err := base64EncPubKey(pubkey)
if err != nil {
return nil, err
}
return &GPGKey{
OwnerID: ownerID,
KeyID: pubkey.KeyIdString(),
PrimaryKeyID: primaryID,
Content: content,
CreatedUnix: util.TimeStamp(pubkey.CreationTime.Unix()),
ExpiredUnix: util.TimeStamp(expiry.Unix()),
CanSign: pubkey.CanSign(),
CanEncryptComms: pubkey.PubKeyAlgo.CanEncrypt(),
CanEncryptStorage: pubkey.PubKeyAlgo.CanEncrypt(),
CanCertify: pubkey.PubKeyAlgo.CanSign(),
}, nil
}
//parseGPGKey parse a PrimaryKey entity (primary key + subs keys + self-signature)
func parseGPGKey(ownerID int64, e *openpgp.Entity) (*GPGKey, error) {
pubkey := e.PrimaryKey
//Extract self-sign for expire date based on : https://github.com/golang/crypto/blob/master/openpgp/keys.go#L165
var selfSig *packet.Signature
for _, ident := range e.Identities {
if selfSig == nil {
selfSig = ident.SelfSignature
} else if ident.SelfSignature.IsPrimaryId != nil && *ident.SelfSignature.IsPrimaryId {
selfSig = ident.SelfSignature
break
}
}
expiry := time.Time{}
if selfSig.KeyLifetimeSecs != nil {
expiry = selfSig.CreationTime.Add(time.Duration(*selfSig.KeyLifetimeSecs) * time.Second)
}
//Parse Subkeys
subkeys := make([]*GPGKey, len(e.Subkeys))
for i, k := range e.Subkeys {
subs, err := parseSubGPGKey(ownerID, pubkey.KeyIdString(), k.PublicKey, expiry)
if err != nil {
return nil, err
}
subkeys[i] = subs
}
//Check emails
userEmails, err := GetEmailAddresses(ownerID)
if err != nil {
return nil, err
}
emails := make([]*EmailAddress, 0, len(e.Identities))
for _, ident := range e.Identities {
email := strings.ToLower(strings.TrimSpace(ident.UserId.Email))
for _, e := range userEmails {
if e.Email == email {
emails = append(emails, e)
break
}
}
}
//In the case no email as been found
if len(emails) == 0 {
failedEmails := make([]string, 0, len(e.Identities))
for _, ident := range e.Identities {
failedEmails = append(failedEmails, ident.UserId.Email)
}
return nil, ErrGPGNoEmailFound{failedEmails}
}
content, err := base64EncPubKey(pubkey)
if err != nil {
return nil, err
}
return &GPGKey{
OwnerID: ownerID,
KeyID: pubkey.KeyIdString(),
PrimaryKeyID: "",
Content: content,
CreatedUnix: util.TimeStamp(pubkey.CreationTime.Unix()),
ExpiredUnix: util.TimeStamp(expiry.Unix()),
Emails: emails,
SubsKey: subkeys,
CanSign: pubkey.CanSign(),
CanEncryptComms: pubkey.PubKeyAlgo.CanEncrypt(),
CanEncryptStorage: pubkey.PubKeyAlgo.CanEncrypt(),
CanCertify: pubkey.PubKeyAlgo.CanSign(),
}, nil
}
// deleteGPGKey does the actual key deletion
func deleteGPGKey(e *xorm.Session, keyID string) (int64, error) {
if keyID == "" {
return 0, fmt.Errorf("empty KeyId forbidden") //Should never happen but just to be sure
}
return e.Where("key_id=?", keyID).Or("primary_key_id=?", keyID).Delete(new(GPGKey))
}
// DeleteGPGKey deletes GPG key information in database.
func DeleteGPGKey(doer *User, id int64) (err error) {
key, err := GetGPGKeyByID(id)
if err != nil {
if IsErrGPGKeyNotExist(err) {
return nil
}
return fmt.Errorf("GetPublicKeyByID: %v", err)
}
// Check if user has access to delete this key.
if !doer.IsAdmin && doer.ID != key.OwnerID {
return ErrGPGKeyAccessDenied{doer.ID, key.ID}
}
sess := x.NewSession()
defer sess.Close()
if err = sess.Begin(); err != nil {
return err
}
if _, err = deleteGPGKey(sess, key.KeyID); err != nil {
return err
}
2017-09-19 08:08:30 +00:00
return sess.Commit()
}
// CommitVerification represents a commit validation of signature
type CommitVerification struct {
Verified bool
Reason string
SigningUser *User
SigningKey *GPGKey
}
// SignCommit represents a commit with validation of signature.
type SignCommit struct {
Verification *CommitVerification
*UserCommit
}
func readerFromBase64(s string) (io.Reader, error) {
bs, err := base64.StdEncoding.DecodeString(s)
if err != nil {
return nil, err
}
return bytes.NewBuffer(bs), nil
}
func populateHash(hashFunc crypto.Hash, msg []byte) (hash.Hash, error) {
h := hashFunc.New()
if _, err := h.Write(msg); err != nil {
return nil, err
}
return h, nil
}
// readArmoredSign read an armored signature block with the given type. https://sourcegraph.com/github.com/golang/crypto/-/blob/openpgp/read.go#L24:6-24:17
func readArmoredSign(r io.Reader) (body io.Reader, err error) {
block, err := armor.Decode(r)
if err != nil {
return
}
if block.Type != openpgp.SignatureType {
return nil, fmt.Errorf("expected '" + openpgp.SignatureType + "', got: " + block.Type)
}
return block.Body, nil
}
func extractSignature(s string) (*packet.Signature, error) {
r, err := readArmoredSign(strings.NewReader(s))
if err != nil {
return nil, fmt.Errorf("Failed to read signature armor")
}
p, err := packet.Read(r)
if err != nil {
return nil, fmt.Errorf("Failed to read signature packet")
}
sig, ok := p.(*packet.Signature)
if !ok {
return nil, fmt.Errorf("Packet is not a signature")
}
return sig, nil
}
func verifySign(s *packet.Signature, h hash.Hash, k *GPGKey) error {
//Check if key can sign
if !k.CanSign {
return fmt.Errorf("key can not sign")
}
//Decode key
b, err := readerFromBase64(k.Content)
if err != nil {
return err
}
//Read key
p, err := packet.Read(b)
if err != nil {
return err
}
//Check type
pkey, ok := p.(*packet.PublicKey)
if !ok {
return fmt.Errorf("key is not a public key")
}
return pkey.VerifySignature(h, s)
}
// ParseCommitWithSignature check if signature is good against keystore.
func ParseCommitWithSignature(c *git.Commit) *CommitVerification {
if c.Signature != nil {
//Parsing signature
sig, err := extractSignature(c.Signature.Signature)
if err != nil { //Skipping failed to extract sign
log.Error(3, "SignatureRead err: %v", err)
return &CommitVerification{
Verified: false,
Reason: "gpg.error.extract_sign",
}
}
//Find Committer account
committer, err := GetUserByEmail(c.Committer.Email) //This find the user by primary email or activated email so commit will not be valid if email is not
if err != nil { //Skipping not user for commiter
// We can expect this to often be an ErrUserNotExist. in the case
// it is not, however, it is important to log it.
if !IsErrUserNotExist(err) {
log.Error(3, "GetUserByEmail: %v", err)
}
return &CommitVerification{
Verified: false,
Reason: "gpg.error.no_committer_account",
}
}
keys, err := ListGPGKeys(committer.ID)
if err != nil { //Skipping failed to get gpg keys of user
log.Error(3, "ListGPGKeys: %v", err)
return &CommitVerification{
Verified: false,
Reason: "gpg.error.failed_retrieval_gpg_keys",
}
}
for _, k := range keys {
//Pre-check (& optimization) that emails attached to key can be attached to the commiter email and can validate
canValidate := false
lowerCommiterEmail := strings.ToLower(c.Committer.Email)
for _, e := range k.Emails {
if e.IsActivated && strings.ToLower(e.Email) == lowerCommiterEmail {
canValidate = true
break
}
}
if !canValidate {
continue //Skip this key
}
//Generating hash of commit
hash, err := populateHash(sig.Hash, []byte(c.Signature.Payload))
if err != nil { //Skipping ailed to generate hash
log.Error(3, "PopulateHash: %v", err)
return &CommitVerification{
Verified: false,
Reason: "gpg.error.generate_hash",
}
}
//We get PK
if err := verifySign(sig, hash, k); err == nil {
return &CommitVerification{ //Everything is ok
Verified: true,
Reason: fmt.Sprintf("%s <%s> / %s", c.Committer.Name, c.Committer.Email, k.KeyID),
SigningUser: committer,
SigningKey: k,
}
}
//And test also SubsKey
for _, sk := range k.SubsKey {
//Generating hash of commit
hash, err := populateHash(sig.Hash, []byte(c.Signature.Payload))
if err != nil { //Skipping ailed to generate hash
log.Error(3, "PopulateHash: %v", err)
return &CommitVerification{
Verified: false,
Reason: "gpg.error.generate_hash",
}
}
if err := verifySign(sig, hash, sk); err == nil {
return &CommitVerification{ //Everything is ok
Verified: true,
Reason: fmt.Sprintf("%s <%s> / %s", c.Committer.Name, c.Committer.Email, sk.KeyID),
SigningUser: committer,
SigningKey: sk,
}
}
}
}
return &CommitVerification{ //Default at this stage
Verified: false,
Reason: "gpg.error.no_gpg_keys_found",
}
}
return &CommitVerification{
Verified: false, //Default value
Reason: "gpg.error.not_signed_commit", //Default value
}
}
// ParseCommitsWithSignature checks if signaute of commits are corresponding to users gpg keys.
func ParseCommitsWithSignature(oldCommits *list.List) *list.List {
var (
newCommits = list.New()
e = oldCommits.Front()
)
for e != nil {
c := e.Value.(UserCommit)
newCommits.PushBack(SignCommit{
UserCommit: &c,
Verification: ParseCommitWithSignature(c.Commit),
})
e = e.Next()
}
return newCommits
}