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>
This commit is contained in:
zeripath 2020-09-19 17:44:55 +01:00 committed by GitHub
parent 89c94e2f8e
commit 4979f15c3f
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
29 changed files with 441 additions and 139 deletions

View file

@ -831,7 +831,7 @@ func ParseCommitsWithSignature(oldCommits *list.List, repository *Repository) *l
newCommits = list.New()
e = oldCommits.Front()
)
memberMap := map[int64]bool{}
keyMap := map[string]bool{}
for e != nil {
c := e.Value.(UserCommit)
@ -840,7 +840,7 @@ func ParseCommitsWithSignature(oldCommits *list.List, repository *Repository) *l
Verification: ParseCommitWithSignature(c.Commit),
}
_ = CalculateTrustStatus(signCommit.Verification, repository, &memberMap)
_ = CalculateTrustStatus(signCommit.Verification, repository, &keyMap)
newCommits.PushBack(signCommit)
e = e.Next()
@ -849,31 +849,70 @@ func ParseCommitsWithSignature(oldCommits *list.List, repository *Repository) *l
}
// CalculateTrustStatus will calculate the TrustStatus for a commit verification within a repository
func CalculateTrustStatus(verification *CommitVerification, repository *Repository, memberMap *map[int64]bool) (err error) {
if verification.Verified {
verification.TrustStatus = "trusted"
if verification.SigningUser.ID != 0 {
var isMember bool
if memberMap != nil {
var has bool
isMember, has = (*memberMap)[verification.SigningUser.ID]
if !has {
isMember, err = repository.IsOwnerMemberCollaborator(verification.SigningUser.ID)
(*memberMap)[verification.SigningUser.ID] = isMember
}
} else {
isMember, err = repository.IsOwnerMemberCollaborator(verification.SigningUser.ID)
}
if !isMember {
verification.TrustStatus = "untrusted"
if verification.CommittingUser.ID != verification.SigningUser.ID {
// The committing user and the signing user are not the same and are not the default key
// This should be marked as questionable unless the signing user is a collaborator/team member etc.
verification.TrustStatus = "unmatched"
}
}
}
func CalculateTrustStatus(verification *CommitVerification, repository *Repository, keyMap *map[string]bool) (err error) {
if !verification.Verified {
return
}
// There are several trust models in Gitea
trustModel := repository.GetTrustModel()
// In the Committer trust model a signature is trusted if it matches the committer
// - it doesn't matter if they're a collaborator, the owner, Gitea or Github
// NB: This model is commit verification only
if trustModel == CommitterTrustModel {
// default to "unmatched"
verification.TrustStatus = "unmatched"
// We can only verify against users in our database but the default key will match
// against by email if it is not in the db.
if (verification.SigningUser.ID != 0 &&
verification.CommittingUser.ID == verification.SigningUser.ID) ||
(verification.SigningUser.ID == 0 && verification.CommittingUser.ID == 0 &&
verification.SigningUser.Email == verification.CommittingUser.Email) {
verification.TrustStatus = "trusted"
}
return
}
// Now we drop to the more nuanced trust models...
verification.TrustStatus = "trusted"
if verification.SigningUser.ID == 0 {
// This commit is signed by the default key - but this key is not assigned to a user in the DB.
// However in the CollaboratorCommitterTrustModel we cannot mark this as trusted
// unless the default key matches the email of a non-user.
if trustModel == CollaboratorCommitterTrustModel && (verification.CommittingUser.ID != 0 ||
verification.SigningUser.Email != verification.CommittingUser.Email) {
verification.TrustStatus = "untrusted"
}
return
}
var isMember bool
if keyMap != nil {
var has bool
isMember, has = (*keyMap)[verification.SigningKey.KeyID]
if !has {
isMember, err = repository.IsOwnerMemberCollaborator(verification.SigningUser.ID)
(*keyMap)[verification.SigningKey.KeyID] = isMember
}
} else {
isMember, err = repository.IsOwnerMemberCollaborator(verification.SigningUser.ID)
}
if !isMember {
verification.TrustStatus = "untrusted"
if verification.CommittingUser.ID != verification.SigningUser.ID {
// The committing user and the signing user are not the same
// This should be marked as questionable unless the signing user is a collaborator/team member etc.
verification.TrustStatus = "unmatched"
}
} else if trustModel == CollaboratorCommitterTrustModel && verification.CommittingUser.ID != verification.SigningUser.ID {
// The committing user and the signing user are not the same and our trustmodel states that they must match
verification.TrustStatus = "unmatched"
}
return
}