Remove undocumented support of signing key in the repository git configuration file (#36143)

Per-repository signing keys have never been officially supported, as
they would require users to modify the repository’s config file.

At this point, it is clear that only global signing keys (GPG or SSH)
should be allowed. If we want to introduce per-repository signing keys
in the future, it will require a complete design proposal.

The endpoint will not be removed for repository special signing key, but
it will reference the global signing key.

---------

Signed-off-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>

modules/git/commit.go

@@ -323,14 +323,6 @@ func GetFullCommitID(ctx context.Context, repoPath, shortID string) (string, err
 	return strings.TrimSpace(commitID), nil
 }
 
-// GetRepositoryDefaultPublicGPGKey returns the default public key for this commit
-func (c *Commit) GetRepositoryDefaultPublicGPGKey(forceUpdate bool) (*GPGSettings, error) {
-	if c.repo == nil {
-		return nil, nil
-	}
-	return c.repo.GetDefaultPublicGPGKey(forceUpdate)
-}
-
 func IsStringLikelyCommitID(objFmt ObjectFormat, s string, minLength ...int) bool {
 	maxLen := 64 // sha256
 	if objFmt != nil {

modules/git/gpg.go

@@ -0,0 +1,102 @@
+// Copyright 2015 The Gogs Authors. All rights reserved.
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+
+	"code.gitea.io/gitea/modules/git/gitcmd"
+	"code.gitea.io/gitea/modules/process"
+)
+
+// GPGSettings represents the default GPG settings for this repository
+type GPGSettings struct {
+	Sign             bool
+	KeyID            string
+	Email            string
+	Name             string
+	PublicKeyContent string
+	Format           string
+}
+
+// LoadPublicKeyContent will load the key from gpg
+func (gpgSettings *GPGSettings) LoadPublicKeyContent() error {
+	if gpgSettings.PublicKeyContent != "" {
+		return nil
+	}
+
+	if gpgSettings.Format == SigningKeyFormatSSH {
+		content, err := os.ReadFile(gpgSettings.KeyID)
+		if err != nil {
+			return fmt.Errorf("unable to read SSH public key file: %s, %w", gpgSettings.KeyID, err)
+		}
+		gpgSettings.PublicKeyContent = string(content)
+		return nil
+	}
+	content, stderr, err := process.GetManager().Exec(
+		"gpg -a --export",
+		"gpg", "-a", "--export", gpgSettings.KeyID)
+	if err != nil {
+		return fmt.Errorf("unable to get default signing key: %s, %s, %w", gpgSettings.KeyID, stderr, err)
+	}
+	gpgSettings.PublicKeyContent = content
+	return nil
+}
+
+var (
+	loadPublicGPGKeyMutex sync.RWMutex
+	globalGPGSettings     *GPGSettings
+)
+
+// GetDefaultPublicGPGKey will return and cache the default public GPG settings
+func GetDefaultPublicGPGKey(ctx context.Context, forceUpdate bool) (*GPGSettings, error) {
+	if !forceUpdate {
+		loadPublicGPGKeyMutex.RLock()
+		if globalGPGSettings != nil {
+			defer loadPublicGPGKeyMutex.RUnlock()
+			return globalGPGSettings, nil
+		}
+		loadPublicGPGKeyMutex.RUnlock()
+	}
+
+	loadPublicGPGKeyMutex.Lock()
+	defer loadPublicGPGKeyMutex.Unlock()
+
+	if globalGPGSettings != nil && !forceUpdate {
+		return globalGPGSettings, nil
+	}
+
+	globalGPGSettings = &GPGSettings{
+		Sign: true,
+	}
+
+	value, _, _ := gitcmd.NewCommand("config", "--global", "--get", "commit.gpgsign").RunStdString(ctx)
+	sign, valid := ParseBool(strings.TrimSpace(value))
+	if !sign || !valid {
+		globalGPGSettings.Sign = false
+		return globalGPGSettings, nil
+	}
+
+	signingKey, _, _ := gitcmd.NewCommand("config", "--global", "--get", "user.signingkey").RunStdString(ctx)
+	globalGPGSettings.KeyID = strings.TrimSpace(signingKey)
+
+	format, _, _ := gitcmd.NewCommand("config", "--global", "--default", SigningKeyFormatOpenPGP, "--get", "gpg.format").RunStdString(ctx)
+	globalGPGSettings.Format = strings.TrimSpace(format)
+
+	defaultEmail, _, _ := gitcmd.NewCommand("config", "--global", "--get", "user.email").RunStdString(ctx)
+	globalGPGSettings.Email = strings.TrimSpace(defaultEmail)
+
+	defaultName, _, _ := gitcmd.NewCommand("config", "--global", "--get", "user.name").RunStdString(ctx)
+	globalGPGSettings.Name = strings.TrimSpace(defaultName)
+
+	if err := globalGPGSettings.LoadPublicKeyContent(); err != nil {
+		return nil, err
+	}
+	return globalGPGSettings, nil
+}

modules/git/key.go

@@ -32,23 +32,23 @@ func (s *SigningKey) String() string {
 }
 
 // GetSigningKey returns the KeyID and git Signature for the repo
-func GetSigningKey(ctx context.Context, repoPath string) (*SigningKey, *Signature) {
+func GetSigningKey(ctx context.Context) (*SigningKey, *Signature) {
 	if setting.Repository.Signing.SigningKey == "none" {
 		return nil, nil
 	}
 
 	if setting.Repository.Signing.SigningKey == "default" || setting.Repository.Signing.SigningKey == "" {
 		// Can ignore the error here as it means that commit.gpgsign is not set
-		value, _, _ := gitcmd.NewCommand("config", "--get", "commit.gpgsign").WithDir(repoPath).RunStdString(ctx)
+		value, _, _ := gitcmd.NewCommand("config", "--global", "--get", "commit.gpgsign").RunStdString(ctx)
 		sign, valid := ParseBool(strings.TrimSpace(value))
 		if !sign || !valid {
 			return nil, nil
 		}
 
-		format, _, _ := gitcmd.NewCommand("config", "--default", SigningKeyFormatOpenPGP, "--get", "gpg.format").WithDir(repoPath).RunStdString(ctx)
-		signingKey, _, _ := gitcmd.NewCommand("config", "--get", "user.signingkey").WithDir(repoPath).RunStdString(ctx)
-		signingName, _, _ := gitcmd.NewCommand("config", "--get", "user.name").WithDir(repoPath).RunStdString(ctx)
-		signingEmail, _, _ := gitcmd.NewCommand("config", "--get", "user.email").WithDir(repoPath).RunStdString(ctx)
+		format, _, _ := gitcmd.NewCommand("config", "--global", "--default", SigningKeyFormatOpenPGP, "--get", "gpg.format").RunStdString(ctx)
+		signingKey, _, _ := gitcmd.NewCommand("config", "--global", "--get", "user.signingkey").RunStdString(ctx)
+		signingName, _, _ := gitcmd.NewCommand("config", "--global", "--get", "user.name").RunStdString(ctx)
+		signingEmail, _, _ := gitcmd.NewCommand("config", "--global", "--get", "user.email").RunStdString(ctx)
 
 		if strings.TrimSpace(signingKey) == "" {
 			return nil, nil

modules/git/repo.go

@@ -20,16 +20,6 @@ import (
 	"code.gitea.io/gitea/modules/proxy"
 )
 
-// GPGSettings represents the default GPG settings for this repository
-type GPGSettings struct {
-	Sign             bool
-	KeyID            string
-	Email            string
-	Name             string
-	PublicKeyContent string
-	Format           string
-}
-
 const prettyLogFormat = `--pretty=format:%H`
 
 func (repo *Repository) ShowPrettyFormatLogToList(ctx context.Context, revisionRange string) ([]*Commit, error) {

modules/git/repo_base_gogit.go

@@ -32,7 +32,6 @@ type Repository struct {
 
 	gogitRepo    *gogit.Repository
 	gogitStorage *filesystem.Storage
-	gpgSettings  *GPGSettings
 
 	Ctx             context.Context
 	LastCommitCache *LastCommitCache

modules/git/repo_base_nogogit.go

@@ -23,8 +23,6 @@ type Repository struct {
 
 	tagCache *ObjectCache[*Tag]
 
-	gpgSettings *GPGSettings
-
 	batchInUse bool
 	batch      *Batch
 

modules/git/repo_gpg.go

@@ -1,71 +0,0 @@
-// Copyright 2015 The Gogs Authors. All rights reserved.
-// Copyright 2017 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package git
-
-import (
-	"fmt"
-	"os"
-	"strings"
-
-	"code.gitea.io/gitea/modules/git/gitcmd"
-	"code.gitea.io/gitea/modules/process"
-)
-
-// LoadPublicKeyContent will load the key from gpg
-func (gpgSettings *GPGSettings) LoadPublicKeyContent() error {
-	if gpgSettings.Format == SigningKeyFormatSSH {
-		content, err := os.ReadFile(gpgSettings.KeyID)
-		if err != nil {
-			return fmt.Errorf("unable to read SSH public key file: %s, %w", gpgSettings.KeyID, err)
-		}
-		gpgSettings.PublicKeyContent = string(content)
-		return nil
-	}
-	content, stderr, err := process.GetManager().Exec(
-		"gpg -a --export",
-		"gpg", "-a", "--export", gpgSettings.KeyID)
-	if err != nil {
-		return fmt.Errorf("unable to get default signing key: %s, %s, %w", gpgSettings.KeyID, stderr, err)
-	}
-	gpgSettings.PublicKeyContent = content
-	return nil
-}
-
-// GetDefaultPublicGPGKey will return and cache the default public GPG settings for this repository
-func (repo *Repository) GetDefaultPublicGPGKey(forceUpdate bool) (*GPGSettings, error) {
-	if repo.gpgSettings != nil && !forceUpdate {
-		return repo.gpgSettings, nil
-	}
-
-	gpgSettings := &GPGSettings{
-		Sign: true,
-	}
-
-	value, _, _ := gitcmd.NewCommand("config", "--get", "commit.gpgsign").WithDir(repo.Path).RunStdString(repo.Ctx)
-	sign, valid := ParseBool(strings.TrimSpace(value))
-	if !sign || !valid {
-		gpgSettings.Sign = false
-		repo.gpgSettings = gpgSettings
-		return gpgSettings, nil
-	}
-
-	signingKey, _, _ := gitcmd.NewCommand("config", "--get", "user.signingkey").WithDir(repo.Path).RunStdString(repo.Ctx)
-	gpgSettings.KeyID = strings.TrimSpace(signingKey)
-
-	format, _, _ := gitcmd.NewCommand("config", "--default", SigningKeyFormatOpenPGP, "--get", "gpg.format").WithDir(repo.Path).RunStdString(repo.Ctx)
-	gpgSettings.Format = strings.TrimSpace(format)
-
-	defaultEmail, _, _ := gitcmd.NewCommand("config", "--get", "user.email").WithDir(repo.Path).RunStdString(repo.Ctx)
-	gpgSettings.Email = strings.TrimSpace(defaultEmail)
-
-	defaultName, _, _ := gitcmd.NewCommand("config", "--get", "user.name").WithDir(repo.Path).RunStdString(repo.Ctx)
-	gpgSettings.Name = strings.TrimSpace(defaultName)
-
-	if err := gpgSettings.LoadPublicKeyContent(); err != nil {
-		return nil, err
-	}
-	repo.gpgSettings = gpgSettings
-	return repo.gpgSettings, nil
-}

modules/gitrepo/signing.go

@@ -9,6 +9,6 @@ import (
 	"code.gitea.io/gitea/modules/git"
 )
 
-func GetSigningKey(ctx context.Context, repo Repository) (*git.SigningKey, *git.Signature) {
-	return git.GetSigningKey(ctx, repoPath(repo))
+func GetSigningKey(ctx context.Context) (*git.SigningKey, *git.Signature) {
+	return git.GetSigningKey(ctx)
 }

routers/api/v1/misc/signing.go

@@ -10,13 +10,8 @@ import (
 )
 
 func getSigningKey(ctx *context.APIContext, expectedFormat string) {
-	// if the handler is in the repo's route group, get the repo's signing key
-	// otherwise, get the global signing key
-	path := ""
-	if ctx.Repo != nil && ctx.Repo.Repository != nil {
-		path = ctx.Repo.Repository.RepoPath()
-	}
-	content, format, err := asymkey_service.PublicSigningKey(ctx, path)
+	// get the global signing key
+	content, format, err := asymkey_service.PublicSigningKey(ctx)
 	if err != nil {
 		ctx.APIErrorInternal(err)
 		return

routers/web/repo/setting/setting.go

@@ -61,7 +61,7 @@ func SettingsCtxData(ctx *context.Context) {
 	ctx.Data["MinimumMirrorInterval"] = setting.Mirror.MinInterval
 	ctx.Data["CanConvertFork"] = ctx.Repo.Repository.IsFork && ctx.Doer.CanCreateRepoIn(ctx.Repo.Repository.Owner)
 
-	signing, _ := gitrepo.GetSigningKey(ctx, ctx.Repo.Repository)
+	signing, _ := gitrepo.GetSigningKey(ctx)
 	ctx.Data["SigningKeyAvailable"] = signing != nil
 	ctx.Data["SigningSettings"] = setting.Repository.Signing
 	ctx.Data["IsRepoIndexerEnabled"] = setting.Indexer.RepoIndexerEnabled
@@ -104,7 +104,7 @@ func SettingsPost(ctx *context.Context) {
 	ctx.Data["DefaultMirrorInterval"] = setting.Mirror.DefaultInterval
 	ctx.Data["MinimumMirrorInterval"] = setting.Mirror.MinInterval
 
-	signing, _ := gitrepo.GetSigningKey(ctx, ctx.Repo.Repository)
+	signing, _ := gitrepo.GetSigningKey(ctx)
 	ctx.Data["SigningKeyAvailable"] = signing != nil
 	ctx.Data["SigningSettings"] = setting.Repository.Signing
 	ctx.Data["IsRepoIndexerEnabled"] = setting.Indexer.RepoIndexerEnabled

services/asymkey/commit.go

@@ -162,7 +162,7 @@ func parseCommitWithGPGSignature(ctx context.Context, c *git.Commit, committer *
 		}
 	}
 
-	defaultGPGSettings, err := c.GetRepositoryDefaultPublicGPGKey(false)
+	defaultGPGSettings, err := git.GetDefaultPublicGPGKey(ctx, false)
 	if err != nil {
 		log.Error("Error getting default public gpg key: %v", err)
 	} else if defaultGPGSettings == nil {

services/asymkey/sign.go

@@ -108,34 +108,34 @@ func IsErrWontSign(err error) bool {
 	return ok
 }
 
-// PublicSigningKey gets the public signing key within a provided repository directory
-func PublicSigningKey(ctx context.Context, repoPath string) (content, format string, err error) {
-	signingKey, _ := git.GetSigningKey(ctx, repoPath)
+// PublicSigningKey gets the public signing key of the entire instance
+func PublicSigningKey(ctx context.Context) (content, format string, err error) {
+	signingKey, _ := git.GetSigningKey(ctx)
 	if signingKey == nil {
 		return "", "", nil
 	}
 	if signingKey.Format == git.SigningKeyFormatSSH {
 		content, err := os.ReadFile(signingKey.KeyID)
 		if err != nil {
-			log.Error("Unable to read SSH public key file in %s: %s, %v", repoPath, signingKey, err)
+			log.Error("Unable to read SSH public key file: %s, %v", signingKey, err)
 			return "", signingKey.Format, err
 		}
 		return string(content), signingKey.Format, nil
 	}
 
-	content, stderr, err := process.GetManager().ExecDir(ctx, -1, repoPath,
+	content, stderr, err := process.GetManager().ExecDir(ctx, -1, setting.Git.HomePath,
 		"gpg --export -a", "gpg", "--export", "-a", signingKey.KeyID)
 	if err != nil {
-		log.Error("Unable to get default signing key in %s: %s, %s, %v", repoPath, signingKey, stderr, err)
+		log.Error("Unable to get default signing key: %s, %s, %v", signingKey, stderr, err)
 		return "", signingKey.Format, err
 	}
 	return content, signingKey.Format, nil
 }
 
 // SignInitialCommit determines if we should sign the initial commit to this repository
-func SignInitialCommit(ctx context.Context, repoPath string, u *user_model.User) (bool, *git.SigningKey, *git.Signature, error) {
+func SignInitialCommit(ctx context.Context, u *user_model.User) (bool, *git.SigningKey, *git.Signature, error) {
 	rules := signingModeFromStrings(setting.Repository.Signing.InitialCommit)
-	signingKey, sig := git.GetSigningKey(ctx, repoPath)
+	signingKey, sig := git.GetSigningKey(ctx)
 	if signingKey == nil {
 		return false, nil, nil, &ErrWontSign{noKey}
 	}
@@ -171,7 +171,7 @@ Loop:
 // SignWikiCommit determines if we should sign the commits to this repository wiki
 func SignWikiCommit(ctx context.Context, repo *repo_model.Repository, u *user_model.User) (bool, *git.SigningKey, *git.Signature, error) {
 	rules := signingModeFromStrings(setting.Repository.Signing.Wiki)
-	signingKey, sig := gitrepo.GetSigningKey(ctx, repo.WikiStorageRepo())
+	signingKey, sig := gitrepo.GetSigningKey(ctx)
 	if signingKey == nil {
 		return false, nil, nil, &ErrWontSign{noKey}
 	}
@@ -222,9 +222,9 @@ Loop:
 }
 
 // SignCRUDAction determines if we should sign a CRUD commit to this repository
-func SignCRUDAction(ctx context.Context, repoPath string, u *user_model.User, tmpBasePath, parentCommit string) (bool, *git.SigningKey, *git.Signature, error) {
+func SignCRUDAction(ctx context.Context, u *user_model.User, tmpBasePath, parentCommit string) (bool, *git.SigningKey, *git.Signature, error) {
 	rules := signingModeFromStrings(setting.Repository.Signing.CRUDActions)
-	signingKey, sig := git.GetSigningKey(ctx, repoPath)
+	signingKey, sig := git.GetSigningKey(ctx)
 	if signingKey == nil {
 		return false, nil, nil, &ErrWontSign{noKey}
 	}
@@ -288,7 +288,7 @@ func SignMerge(ctx context.Context, pr *issues_model.PullRequest, u *user_model.
 	}
 	repo := pr.BaseRepo
 
-	signingKey, signer := gitrepo.GetSigningKey(ctx, repo)
+	signingKey, signer := gitrepo.GetSigningKey(ctx)
 	if signingKey == nil {
 		return false, nil, nil, &ErrWontSign{noKey}
 	}

services/context/repo.go

@@ -140,7 +140,7 @@ func PrepareCommitFormOptions(ctx *Context, doer *user_model.User, targetRepo *r
 		protectionRequireSigned = protectedBranch.RequireSignedCommits
 	}
 
-	willSign, signKey, _, err := asymkey_service.SignCRUDAction(ctx, targetRepo.RepoPath(), doer, targetRepo.RepoPath(), refName.String())
+	willSign, signKey, _, err := asymkey_service.SignCRUDAction(ctx, doer, targetRepo.RepoPath(), refName.String())
 	wontSignReason := ""
 	if asymkey_service.IsErrWontSign(err) {
 		wontSignReason = string(err.(*asymkey_service.ErrWontSign).Reason)

services/repository/files/patch.go

@@ -95,7 +95,7 @@ func (opts *ApplyDiffPatchOptions) Validate(ctx context.Context, repo *repo_mode
 			}
 		}
 		if protectedBranch != nil && protectedBranch.RequireSignedCommits {
-			_, _, _, err := asymkey_service.SignCRUDAction(ctx, repo.RepoPath(), doer, repo.RepoPath(), opts.OldBranch)
+			_, _, _, err := asymkey_service.SignCRUDAction(ctx, doer, repo.RepoPath(), opts.OldBranch)
 			if err != nil {
 				if !asymkey_service.IsErrWontSign(err) {
 					return err

services/repository/files/temp_repo.go

@@ -303,9 +303,9 @@ func (t *TemporaryUploadRepository) CommitTree(ctx context.Context, opts *Commit
 	var key *git.SigningKey
 	var signer *git.Signature
 	if opts.ParentCommitID != "" {
-		sign, key, signer, _ = asymkey_service.SignCRUDAction(ctx, t.repo.RepoPath(), opts.DoerUser, t.basePath, opts.ParentCommitID)
+		sign, key, signer, _ = asymkey_service.SignCRUDAction(ctx, opts.DoerUser, t.basePath, opts.ParentCommitID)
 	} else {
-		sign, key, signer, _ = asymkey_service.SignInitialCommit(ctx, t.repo.RepoPath(), opts.DoerUser)
+		sign, key, signer, _ = asymkey_service.SignInitialCommit(ctx, opts.DoerUser)
 	}
 	if sign {
 		if key.Format != "" {

services/repository/files/update.go

@@ -686,7 +686,7 @@ func VerifyBranchProtection(ctx context.Context, repo *repo_model.Repository, do
 			}
 		}
 		if protectedBranch.RequireSignedCommits {
-			_, _, _, err := asymkey_service.SignCRUDAction(ctx, repo.RepoPath(), doer, repo.RepoPath(), branchName)
+			_, _, _, err := asymkey_service.SignCRUDAction(ctx, doer, repo.RepoPath(), branchName)
 			if err != nil {
 				if !asymkey_service.IsErrWontSign(err) {
 					return err

services/repository/init.go

@@ -41,7 +41,7 @@ func initRepoCommit(ctx context.Context, tmpPath string, repo *repo_model.Reposi
 	cmd := gitcmd.NewCommand("commit", "--message=Initial commit").
 		AddOptionFormat("--author='%s <%s>'", sig.Name, sig.Email)
 
-	sign, key, signer, _ := asymkey_service.SignInitialCommit(ctx, tmpPath, u)
+	sign, key, signer, _ := asymkey_service.SignInitialCommit(ctx, u)
 	if sign {
 		if key.Format != "" {
 			cmd.AddConfig("gpg.format", key.Format)