Add configurable Trust Models (#11712)

* Add configurable Trust Models

Gitea's default signature verification model differs from GitHub. GitHub
uses signatures to verify that the committer is who they say they are -
meaning that when GitHub makes a signed commit it must be the committer.
The GitHub model prevents re-publishing of commits after revocation of a
key and prevents re-signing of other people's commits to create a
completely trusted repository signed by one key or a set of trusted
keys.

The default behaviour of Gitea in contrast is to always display the
avatar and information related to a signature. This allows signatures to
be decoupled from the committer. That being said, allowing arbitary
users to present other peoples commits as theirs is not necessarily
desired therefore we have a trust model whereby signatures from
collaborators are marked trusted, signatures matching the commit line
are marked untrusted and signatures that match a user in the db but not
the committer line are marked unmatched.

The problem with this model is that this conflicts with Github therefore
we need to provide an option to allow users to choose the Github model
should they wish to.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Adjust locale strings

Signed-off-by: Andrew Thornton <art27@cantab.net>

* as per @6543

Co-authored-by: 6543 <6543@obermui.de>

* Update models/gpg_key.go

* Add migration for repository

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/models/repo.go b/models/repo.go
index 2bbc74f439..25fe3f63d3 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -143,6 +143,47 @@ const (
 	RepositoryBeingMigrated                         // repository is migrating
 )
 
+// TrustModelType defines the types of trust model for this repository
+type TrustModelType int
+
+// kinds of TrustModel
+const (
+	DefaultTrustModel TrustModelType = iota // default trust model
+	CommitterTrustModel
+	CollaboratorTrustModel
+	CollaboratorCommitterTrustModel
+)
+
+// String converts a TrustModelType to a string
+func (t TrustModelType) String() string {
+	switch t {
+	case DefaultTrustModel:
+		return "default"
+	case CommitterTrustModel:
+		return "committer"
+	case CollaboratorTrustModel:
+		return "collaborator"
+	case CollaboratorCommitterTrustModel:
+		return "collaboratorcommitter"
+	}
+	return "default"
+}
+
+// ToTrustModel converts a string to a TrustModelType
+func ToTrustModel(model string) TrustModelType {
+	switch strings.ToLower(strings.TrimSpace(model)) {
+	case "default":
+		return DefaultTrustModel
+	case "collaborator":
+		return CollaboratorTrustModel
+	case "committer":
+		return CommitterTrustModel
+	case "collaboratorcommitter":
+		return CollaboratorCommitterTrustModel
+	}
+	return DefaultTrustModel
+}
+
 // Repository represents a git repository.
 type Repository struct {
 	ID                  int64 `xorm:"pk autoincr"`
@@ -198,6 +239,8 @@ type Repository struct {
 	CloseIssuesViaCommitInAnyBranch bool               `xorm:"NOT NULL DEFAULT false"`
 	Topics                          []string           `xorm:"TEXT JSON"`
 
+	TrustModel TrustModelType
+
 	// Avatar: ID(10-20)-md5(32) - must fit into 64 symbols
 	Avatar string `xorm:"VARCHAR(64)"`
 
@@ -1038,6 +1081,7 @@ type CreateRepoOptions struct {
 	IsMirror       bool
 	AutoInit       bool
 	Status         RepositoryStatus
+	TrustModel     TrustModelType
 }
 
 // GetRepoInitFile returns repository init files
@@ -2383,6 +2427,18 @@ func UpdateRepositoryCols(repo *Repository, cols ...string) error {
 	return updateRepositoryCols(x, repo, cols...)
 }
 
+// GetTrustModel will get the TrustModel for the repo or the default trust model
+func (repo *Repository) GetTrustModel() TrustModelType {
+	trustModel := repo.TrustModel
+	if trustModel == DefaultTrustModel {
+		trustModel = ToTrustModel(setting.Repository.Signing.DefaultTrustModel)
+		if trustModel == DefaultTrustModel {
+			return CollaboratorTrustModel
+		}
+	}
+	return trustModel
+}
+
 // DoctorUserStarNum recalculate Stars number for all user
 func DoctorUserStarNum() (err error) {
 	const batchSize = 100