gitea/services/asymkey/commit.go

364 lines
12 KiB
Go

// Copyright 2025 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package asymkey
import (
"context"
"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/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"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 {
var committer *user_model.User
if c.Committer != nil {
var err error
// Find Committer account
committer, err = user_model.GetUserByEmail(ctx, c.Committer.Email) // This finds 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 committer
committer = &user_model.User{
Name: c.Committer.Name,
Email: c.Committer.Email,
}
// We can expect this to often be an ErrUserNotExist. in the case
// it is not, however, it is important to log it.
if !user_model.IsErrUserNotExist(err) {
log.Error("GetUserByEmail: %v", err)
return &asymkey_model.CommitVerification{
CommittingUser: committer,
Verified: false,
Reason: "gpg.error.no_committer_account",
}
}
}
}
return ParseCommitWithSignatureCommitter(ctx, c, committer)
}
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, // Default value
Reason: "gpg.error.not_signed_commit", // Default value
}
}
// If this a SSH signature handle it differently
if strings.HasPrefix(c.Signature.Signature, "-----BEGIN SSH SIGNATURE-----") {
return asymkey_model.ParseCommitWithSSHSignature(ctx, c, committer)
}
// 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",
}
}
committerEmailAddresses, _ := user_model.GetEmailAddresses(ctx, committer.ID)
activated := false
for _, e := range committerEmailAddresses {
if e.IsActivated && strings.EqualFold(e.Email, c.Committer.Email) {
activated = true
break
}
}
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 && activated {
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, _ = user_model.GetEmailAddresses(ctx, key.OwnerID)
uid = key.OwnerID
user = &user_model.User{ID: uid}
_, _ = user_model.GetUser(ctx, user)
}
for _, e := range userEmails {
if e.IsActivated && (email == "" || strings.EqualFold(e.Email, email)) {
return true, e.Email
}
}
if user.KeepEmailPrivate && strings.EqualFold(email, user.GetEmail()) {
return true, user.GetEmail()
}
}
}
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 := db.Find[asymkey_model.GPGKey](ctx, asymkey_model.FindGPGKeyOptions{
KeyID: keyID,
IncludeSubKeys: true,
})
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 = db.Find[asymkey_model.GPGKey](ctx, asymkey_model.FindGPGKeyOptions{
KeyID: key.PrimaryKeyID,
IncludeSubKeys: true,
})
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 := user_model.GetUserByID(ctx, key.OwnerID)
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
}