mirror of
https://github.com/go-gitea/gitea.git
synced 2025-10-31 11:41:32 +01:00
451 lines
16 KiB
Go
451 lines
16 KiB
Go
// Copyright 2025 The Gitea Authors. All rights reserved.
|
|
// SPDX-License-Identifier: MIT
|
|
|
|
package asymkey
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"slices"
|
|
"strings"
|
|
|
|
asymkey_model "code.gitea.io/gitea/models/asymkey"
|
|
"code.gitea.io/gitea/models/db"
|
|
user_model "code.gitea.io/gitea/models/user"
|
|
"code.gitea.io/gitea/modules/cache"
|
|
"code.gitea.io/gitea/modules/cachegroup"
|
|
"code.gitea.io/gitea/modules/git"
|
|
"code.gitea.io/gitea/modules/log"
|
|
"code.gitea.io/gitea/modules/setting"
|
|
|
|
"github.com/42wim/sshsig"
|
|
"github.com/ProtonMail/go-crypto/openpgp/packet"
|
|
)
|
|
|
|
// ParseCommitWithSignature check if signature is good against keystore.
|
|
func ParseCommitWithSignature(ctx context.Context, c *git.Commit) *asymkey_model.CommitVerification {
|
|
committer, err := user_model.GetUserByEmail(ctx, c.Committer.Email)
|
|
if err != nil && !user_model.IsErrUserNotExist(err) {
|
|
log.Error("GetUserByEmail: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
Verified: false,
|
|
Reason: "gpg.error.no_committer_account", // this error is not right, but such error should seldom happen
|
|
}
|
|
}
|
|
return ParseCommitWithSignatureCommitter(ctx, c, committer)
|
|
}
|
|
|
|
// ParseCommitWithSignatureCommitter parses a commit's GPG or SSH signature.
|
|
// The caller guarantees that the committer user is related to the commit by checking its activated email addresses or no-reply address.
|
|
// If the commit is singed by an instance key, then committer can be nil.
|
|
// If the signature exists, even if committer is nil, the returned CommittingUser will be a non-nil fake user (e.g.: instance key)
|
|
func ParseCommitWithSignatureCommitter(ctx context.Context, c *git.Commit, committer *user_model.User) *asymkey_model.CommitVerification {
|
|
// If no signature, just report the committer
|
|
if c.Signature == nil {
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.not_signed_commit",
|
|
}
|
|
}
|
|
// to support instance key, we need a fake committer user (not really needed, but legacy code accesses the committer without nil-check)
|
|
if committer == nil {
|
|
committer = &user_model.User{
|
|
Name: c.Committer.Name,
|
|
Email: c.Committer.Email,
|
|
}
|
|
}
|
|
if strings.HasPrefix(c.Signature.Signature, "-----BEGIN SSH SIGNATURE-----") {
|
|
return parseCommitWithSSHSignature(ctx, c, committer)
|
|
}
|
|
return parseCommitWithGPGSignature(ctx, c, committer)
|
|
}
|
|
|
|
func parseCommitWithGPGSignature(ctx context.Context, c *git.Commit, committer *user_model.User) *asymkey_model.CommitVerification {
|
|
// Parsing signature
|
|
sig, err := asymkey_model.ExtractSignature(c.Signature.Signature)
|
|
if err != nil { // Skipping failed to extract sign
|
|
log.Error("SignatureRead err: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.extract_sign",
|
|
}
|
|
}
|
|
|
|
keyID := asymkey_model.TryGetKeyIDFromSignature(sig)
|
|
defaultReason := asymkey_model.NoKeyFound
|
|
|
|
// First check if the sig has a keyID and if so just look at that
|
|
if commitVerification := HashAndVerifyForKeyID(
|
|
ctx,
|
|
sig,
|
|
c.Signature.Payload,
|
|
committer,
|
|
keyID,
|
|
setting.AppName,
|
|
""); commitVerification != nil {
|
|
if commitVerification.Reason == asymkey_model.BadSignature {
|
|
defaultReason = asymkey_model.BadSignature
|
|
} else {
|
|
return commitVerification
|
|
}
|
|
}
|
|
|
|
// Now try to associate the signature with the committer, if present
|
|
if committer.ID != 0 {
|
|
keys, err := db.Find[asymkey_model.GPGKey](ctx, asymkey_model.FindGPGKeyOptions{
|
|
OwnerID: committer.ID,
|
|
})
|
|
if err != nil { // Skipping failed to get gpg keys of user
|
|
log.Error("ListGPGKeys: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.failed_retrieval_gpg_keys",
|
|
}
|
|
}
|
|
|
|
if err := asymkey_model.GPGKeyList(keys).LoadSubKeys(ctx); err != nil {
|
|
log.Error("LoadSubKeys: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
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 committer email and can validate
|
|
canValidate := false
|
|
email := ""
|
|
if k.Verified {
|
|
canValidate = true
|
|
email = c.Committer.Email
|
|
}
|
|
if !canValidate {
|
|
for _, e := range k.Emails {
|
|
if e.IsActivated && strings.EqualFold(e.Email, c.Committer.Email) {
|
|
canValidate = true
|
|
email = e.Email
|
|
break
|
|
}
|
|
}
|
|
}
|
|
if !canValidate {
|
|
continue // Skip this key
|
|
}
|
|
|
|
commitVerification := asymkey_model.HashAndVerifyWithSubKeysCommitVerification(sig, c.Signature.Payload, k, committer, committer, email)
|
|
if commitVerification != nil {
|
|
return commitVerification
|
|
}
|
|
}
|
|
}
|
|
|
|
if setting.Repository.Signing.SigningKey != "" && setting.Repository.Signing.SigningKey != "default" && setting.Repository.Signing.SigningKey != "none" {
|
|
// OK we should try the default key
|
|
gpgSettings := git.GPGSettings{
|
|
Sign: true,
|
|
KeyID: setting.Repository.Signing.SigningKey,
|
|
Name: setting.Repository.Signing.SigningName,
|
|
Email: setting.Repository.Signing.SigningEmail,
|
|
}
|
|
if err := gpgSettings.LoadPublicKeyContent(); err != nil {
|
|
log.Error("Error getting default signing key: %s %v", gpgSettings.KeyID, err)
|
|
} else if commitVerification := verifyWithGPGSettings(ctx, &gpgSettings, sig, c.Signature.Payload, committer, keyID); commitVerification != nil {
|
|
if commitVerification.Reason == asymkey_model.BadSignature {
|
|
defaultReason = asymkey_model.BadSignature
|
|
} else {
|
|
return commitVerification
|
|
}
|
|
}
|
|
}
|
|
|
|
defaultGPGSettings, err := c.GetRepositoryDefaultPublicGPGKey(false)
|
|
if err != nil {
|
|
log.Error("Error getting default public gpg key: %v", err)
|
|
} else if defaultGPGSettings == nil {
|
|
log.Warn("Unable to get defaultGPGSettings for unattached commit: %s", c.ID.String())
|
|
} else if defaultGPGSettings.Sign {
|
|
if commitVerification := verifyWithGPGSettings(ctx, defaultGPGSettings, sig, c.Signature.Payload, committer, keyID); commitVerification != nil {
|
|
if commitVerification.Reason == asymkey_model.BadSignature {
|
|
defaultReason = asymkey_model.BadSignature
|
|
} else {
|
|
return commitVerification
|
|
}
|
|
}
|
|
}
|
|
|
|
return &asymkey_model.CommitVerification{ // Default at this stage
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Warning: defaultReason != asymkey_model.NoKeyFound,
|
|
Reason: defaultReason,
|
|
SigningKey: &asymkey_model.GPGKey{
|
|
KeyID: keyID,
|
|
},
|
|
}
|
|
}
|
|
|
|
func checkKeyEmails(ctx context.Context, email string, keys ...*asymkey_model.GPGKey) (bool, string) {
|
|
uid := int64(0)
|
|
var userEmails []*user_model.EmailAddress
|
|
var user *user_model.User
|
|
for _, key := range keys {
|
|
for _, e := range key.Emails {
|
|
if e.IsActivated && (email == "" || strings.EqualFold(e.Email, email)) {
|
|
return true, e.Email
|
|
}
|
|
}
|
|
if key.Verified && key.OwnerID != 0 {
|
|
if uid != key.OwnerID {
|
|
userEmails, _ = cache.GetWithContextCache(ctx, cachegroup.UserEmailAddresses, key.OwnerID, user_model.GetEmailAddresses)
|
|
uid = key.OwnerID
|
|
user, _ = cache.GetWithContextCache(ctx, cachegroup.User, uid, user_model.GetUserByID)
|
|
}
|
|
for _, e := range userEmails {
|
|
if e.IsActivated && (email == "" || strings.EqualFold(e.Email, email)) {
|
|
return true, e.Email
|
|
}
|
|
}
|
|
if user != nil && strings.EqualFold(email, user.GetPlaceholderEmail()) {
|
|
return true, user.GetPlaceholderEmail()
|
|
}
|
|
}
|
|
}
|
|
return false, email
|
|
}
|
|
|
|
func HashAndVerifyForKeyID(ctx context.Context, sig *packet.Signature, payload string, committer *user_model.User, keyID, name, email string) *asymkey_model.CommitVerification {
|
|
if keyID == "" {
|
|
return nil
|
|
}
|
|
keys, err := cache.GetWithContextCache(ctx, cachegroup.GPGKeyWithSubKeys, keyID, asymkey_model.FindGPGKeyWithSubKeys)
|
|
if err != nil {
|
|
log.Error("GetGPGKeysByKeyID: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.failed_retrieval_gpg_keys",
|
|
}
|
|
}
|
|
if len(keys) == 0 {
|
|
return nil
|
|
}
|
|
for _, key := range keys {
|
|
var primaryKeys []*asymkey_model.GPGKey
|
|
if key.PrimaryKeyID != "" {
|
|
primaryKeys, err = cache.GetWithContextCache(ctx, cachegroup.GPGKeyWithSubKeys, key.PrimaryKeyID, asymkey_model.FindGPGKeyWithSubKeys)
|
|
if err != nil {
|
|
log.Error("GetGPGKeysByKeyID: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.failed_retrieval_gpg_keys",
|
|
}
|
|
}
|
|
}
|
|
|
|
activated, email := checkKeyEmails(ctx, email, append([]*asymkey_model.GPGKey{key}, primaryKeys...)...)
|
|
if !activated {
|
|
continue
|
|
}
|
|
|
|
signer := &user_model.User{
|
|
Name: name,
|
|
Email: email,
|
|
}
|
|
if key.OwnerID > 0 {
|
|
owner, err := cache.GetWithContextCache(ctx, cachegroup.User, key.OwnerID, user_model.GetUserByID)
|
|
if err == nil {
|
|
signer = owner
|
|
} else if !user_model.IsErrUserNotExist(err) {
|
|
log.Error("Failed to user_model.GetUserByID: %d for key ID: %d (%s) %v", key.OwnerID, key.ID, key.KeyID, err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.no_committer_account",
|
|
}
|
|
}
|
|
}
|
|
commitVerification := asymkey_model.HashAndVerifyWithSubKeysCommitVerification(sig, payload, key, committer, signer, email)
|
|
if commitVerification != nil {
|
|
return commitVerification
|
|
}
|
|
}
|
|
// This is a bad situation ... We have a key id that is in our database but the signature doesn't match.
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Warning: true,
|
|
Reason: asymkey_model.BadSignature,
|
|
}
|
|
}
|
|
|
|
func verifyWithGPGSettings(ctx context.Context, gpgSettings *git.GPGSettings, sig *packet.Signature, payload string, committer *user_model.User, keyID string) *asymkey_model.CommitVerification {
|
|
// First try to find the key in the db
|
|
if commitVerification := HashAndVerifyForKeyID(ctx, sig, payload, committer, gpgSettings.KeyID, gpgSettings.Name, gpgSettings.Email); commitVerification != nil {
|
|
return commitVerification
|
|
}
|
|
|
|
// Otherwise we have to parse the key
|
|
ekeys, err := asymkey_model.CheckArmoredGPGKeyString(gpgSettings.PublicKeyContent)
|
|
if err != nil {
|
|
log.Error("Unable to get default signing key: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.generate_hash",
|
|
}
|
|
}
|
|
for _, ekey := range ekeys {
|
|
pubkey := ekey.PrimaryKey
|
|
content, err := asymkey_model.Base64EncPubKey(pubkey)
|
|
if err != nil {
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.generate_hash",
|
|
}
|
|
}
|
|
k := &asymkey_model.GPGKey{
|
|
Content: content,
|
|
CanSign: pubkey.CanSign(),
|
|
KeyID: pubkey.KeyIdString(),
|
|
}
|
|
for _, subKey := range ekey.Subkeys {
|
|
content, err := asymkey_model.Base64EncPubKey(subKey.PublicKey)
|
|
if err != nil {
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Reason: "gpg.error.generate_hash",
|
|
}
|
|
}
|
|
k.SubsKey = append(k.SubsKey, &asymkey_model.GPGKey{
|
|
Content: content,
|
|
CanSign: subKey.PublicKey.CanSign(),
|
|
KeyID: subKey.PublicKey.KeyIdString(),
|
|
})
|
|
}
|
|
if commitVerification := asymkey_model.HashAndVerifyWithSubKeysCommitVerification(sig, payload, k, committer, &user_model.User{
|
|
Name: gpgSettings.Name,
|
|
Email: gpgSettings.Email,
|
|
}, gpgSettings.Email); commitVerification != nil {
|
|
return commitVerification
|
|
}
|
|
if keyID == k.KeyID {
|
|
// This is a bad situation ... We have a key id that matches our default key but the signature doesn't match.
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committer,
|
|
Verified: false,
|
|
Warning: true,
|
|
Reason: asymkey_model.BadSignature,
|
|
}
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func verifySSHCommitVerificationByInstanceKey(c *git.Commit, committerUser, signerUser *user_model.User, committerGitEmail, publicKeyContent string) *asymkey_model.CommitVerification {
|
|
fingerprint, err := asymkey_model.CalcFingerprint(publicKeyContent)
|
|
if err != nil {
|
|
log.Error("Error calculating the fingerprint public key %q, err: %v", publicKeyContent, err)
|
|
return nil
|
|
}
|
|
sshPubKey := &asymkey_model.PublicKey{
|
|
Verified: true,
|
|
Content: publicKeyContent,
|
|
Fingerprint: fingerprint,
|
|
HasUsed: true,
|
|
}
|
|
return verifySSHCommitVerification(c.Signature.Signature, c.Signature.Payload, sshPubKey, committerUser, signerUser, committerGitEmail)
|
|
}
|
|
|
|
// parseCommitWithSSHSignature check if signature is good against keystore.
|
|
func parseCommitWithSSHSignature(ctx context.Context, c *git.Commit, committerUser *user_model.User) *asymkey_model.CommitVerification {
|
|
// Now try to associate the signature with the committer, if present
|
|
if committerUser.ID != 0 {
|
|
keys, err := db.Find[asymkey_model.PublicKey](ctx, asymkey_model.FindPublicKeyOptions{
|
|
OwnerID: committerUser.ID,
|
|
NotKeytype: asymkey_model.KeyTypePrincipal,
|
|
})
|
|
if err != nil { // Skipping failed to get ssh keys of user
|
|
log.Error("ListPublicKeys: %v", err)
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committerUser,
|
|
Verified: false,
|
|
Reason: "gpg.error.failed_retrieval_gpg_keys",
|
|
}
|
|
}
|
|
|
|
for _, k := range keys {
|
|
if k.Verified {
|
|
commitVerification := verifySSHCommitVerification(c.Signature.Signature, c.Signature.Payload, k, committerUser, committerUser, c.Committer.Email)
|
|
if commitVerification != nil {
|
|
return commitVerification
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Try the pre-set trusted keys (for key-rotation purpose)
|
|
// At the moment, we still use the SigningName&SigningEmail for the rotated keys.
|
|
// Maybe in the future we can extend the key format to "ssh-xxx .... old-user@example.com" to support different signer emails.
|
|
for _, k := range setting.Repository.Signing.TrustedSSHKeys {
|
|
signerUser := &user_model.User{
|
|
Name: setting.Repository.Signing.SigningName,
|
|
Email: setting.Repository.Signing.SigningEmail,
|
|
}
|
|
commitVerification := verifySSHCommitVerificationByInstanceKey(c, committerUser, signerUser, c.Committer.Email, k)
|
|
if commitVerification != nil && commitVerification.Verified {
|
|
return commitVerification
|
|
}
|
|
}
|
|
|
|
// Try the configured instance-wide SSH public key
|
|
if setting.Repository.Signing.SigningFormat == git.SigningKeyFormatSSH && !slices.Contains([]string{"", "default", "none"}, setting.Repository.Signing.SigningKey) {
|
|
gpgSettings := git.GPGSettings{
|
|
Sign: true,
|
|
KeyID: setting.Repository.Signing.SigningKey,
|
|
Name: setting.Repository.Signing.SigningName,
|
|
Email: setting.Repository.Signing.SigningEmail,
|
|
Format: setting.Repository.Signing.SigningFormat,
|
|
}
|
|
signerUser := &user_model.User{
|
|
Name: gpgSettings.Name,
|
|
Email: gpgSettings.Email,
|
|
}
|
|
if err := gpgSettings.LoadPublicKeyContent(); err != nil {
|
|
log.Error("Error getting instance-wide SSH signing key %q, err: %v", gpgSettings.KeyID, err)
|
|
} else {
|
|
commitVerification := verifySSHCommitVerificationByInstanceKey(c, committerUser, signerUser, gpgSettings.Email, gpgSettings.PublicKeyContent)
|
|
if commitVerification != nil && commitVerification.Verified {
|
|
return commitVerification
|
|
}
|
|
}
|
|
}
|
|
|
|
return &asymkey_model.CommitVerification{
|
|
CommittingUser: committerUser,
|
|
Verified: false,
|
|
Reason: asymkey_model.NoKeyFound,
|
|
}
|
|
}
|
|
|
|
func verifySSHCommitVerification(sig, payload string, k *asymkey_model.PublicKey, committer, signer *user_model.User, email string) *asymkey_model.CommitVerification {
|
|
if err := sshsig.Verify(strings.NewReader(payload), []byte(sig), []byte(k.Content), "git"); err != nil {
|
|
return nil
|
|
}
|
|
|
|
return &asymkey_model.CommitVerification{ // Everything is ok
|
|
CommittingUser: committer,
|
|
Verified: true,
|
|
Reason: fmt.Sprintf("%s / %s", signer.Name, k.Fingerprint),
|
|
SigningUser: signer,
|
|
SigningSSHKey: k,
|
|
SigningEmail: email,
|
|
}
|
|
}
|