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mirror of https://github.com/go-gitea/gitea synced 2024-12-23 09:04:26 +00:00
gitea/models/repo_sign.go
zeripath fcb535c5c3
Sign merges, CRUD, Wiki and Repository initialisation with gpg key (#7631)
This PR fixes #7598 by providing a configurable way of signing commits across the Gitea instance. Per repository configurability and import/generation of trusted secure keys is not provided by this PR - from a security PoV that's probably impossible to do properly. Similarly web-signing, that is asking the user to sign something, is not implemented - this could be done at a later stage however.

## Features
- [x] If commit.gpgsign is set in .gitconfig sign commits and files created through repofiles. (merges should already have been signed.)
- [x] Verify commits signed with the default gpg as valid
- [x] Signer, Committer and Author can all be different
    - [x] Allow signer to be arbitrarily different - We still require the key to have an activated email on Gitea. A more complete implementation would be to use a keyserver and mark external-or-unactivated with an "unknown" trust level icon.
- [x] Add a signing-key.gpg endpoint to get the default gpg pub key if available
    - Rather than add a fake web-flow user I've added this as an endpoint on /api/v1/signing-key.gpg
    - [x] Try to match the default key with a user on gitea - this is done at verification time
- [x] Make things configurable?
    - app.ini configuration done
    - [x] when checking commits are signed need to check if they're actually verifiable too
- [x] Add documentation

I have decided that adjusting the docker to create a default gpg key is not the correct thing to do and therefore have not implemented this.
2019-10-16 14:42:42 +01:00

304 lines
7.4 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package models
import (
"strings"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/process"
"code.gitea.io/gitea/modules/setting"
)
type signingMode string
const (
never signingMode = "never"
always signingMode = "always"
pubkey signingMode = "pubkey"
twofa signingMode = "twofa"
parentSigned signingMode = "parentsigned"
baseSigned signingMode = "basesigned"
headSigned signingMode = "headsigned"
commitsSigned signingMode = "commitssigned"
)
func signingModeFromStrings(modeStrings []string) []signingMode {
returnable := make([]signingMode, 0, len(modeStrings))
for _, mode := range modeStrings {
signMode := signingMode(strings.ToLower(mode))
switch signMode {
case never:
return []signingMode{never}
case always:
return []signingMode{always}
case pubkey:
fallthrough
case twofa:
fallthrough
case parentSigned:
fallthrough
case baseSigned:
fallthrough
case headSigned:
fallthrough
case commitsSigned:
returnable = append(returnable, signMode)
}
}
if len(returnable) == 0 {
return []signingMode{never}
}
return returnable
}
func signingKey(repoPath string) string {
if setting.Repository.Signing.SigningKey == "none" {
return ""
}
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, _ := git.NewCommand("config", "--get", "commit.gpgsign").RunInDir(repoPath)
sign, valid := git.ParseBool(strings.TrimSpace(value))
if !sign || !valid {
return ""
}
signingKey, _ := git.NewCommand("config", "--get", "user.signingkey").RunInDir(repoPath)
return strings.TrimSpace(signingKey)
}
return setting.Repository.Signing.SigningKey
}
// PublicSigningKey gets the public signing key within a provided repository directory
func PublicSigningKey(repoPath string) (string, error) {
signingKey := signingKey(repoPath)
if signingKey == "" {
return "", nil
}
content, stderr, err := process.GetManager().ExecDir(-1, repoPath,
"gpg --export -a", "gpg", "--export", "-a", signingKey)
if err != nil {
log.Error("Unable to get default signing key in %s: %s, %s, %v", repoPath, signingKey, stderr, err)
return "", err
}
return content, nil
}
// SignInitialCommit determines if we should sign the initial commit to this repository
func SignInitialCommit(repoPath string, u *User) (bool, string) {
rules := signingModeFromStrings(setting.Repository.Signing.InitialCommit)
signingKey := signingKey(repoPath)
if signingKey == "" {
return false, ""
}
for _, rule := range rules {
switch rule {
case never:
return false, ""
case always:
break
case pubkey:
keys, err := ListGPGKeys(u.ID)
if err != nil || len(keys) == 0 {
return false, ""
}
case twofa:
twofa, err := GetTwoFactorByUID(u.ID)
if err != nil || twofa == nil {
return false, ""
}
}
}
return true, signingKey
}
// SignWikiCommit determines if we should sign the commits to this repository wiki
func (repo *Repository) SignWikiCommit(u *User) (bool, string) {
rules := signingModeFromStrings(setting.Repository.Signing.Wiki)
signingKey := signingKey(repo.WikiPath())
if signingKey == "" {
return false, ""
}
for _, rule := range rules {
switch rule {
case never:
return false, ""
case always:
break
case pubkey:
keys, err := ListGPGKeys(u.ID)
if err != nil || len(keys) == 0 {
return false, ""
}
case twofa:
twofa, err := GetTwoFactorByUID(u.ID)
if err != nil || twofa == nil {
return false, ""
}
case parentSigned:
gitRepo, err := git.OpenRepository(repo.WikiPath())
if err != nil {
return false, ""
}
commit, err := gitRepo.GetCommit("HEAD")
if err != nil {
return false, ""
}
if commit.Signature == nil {
return false, ""
}
verification := ParseCommitWithSignature(commit)
if !verification.Verified {
return false, ""
}
}
}
return true, signingKey
}
// SignCRUDAction determines if we should sign a CRUD commit to this repository
func (repo *Repository) SignCRUDAction(u *User, tmpBasePath, parentCommit string) (bool, string) {
rules := signingModeFromStrings(setting.Repository.Signing.CRUDActions)
signingKey := signingKey(repo.RepoPath())
if signingKey == "" {
return false, ""
}
for _, rule := range rules {
switch rule {
case never:
return false, ""
case always:
break
case pubkey:
keys, err := ListGPGKeys(u.ID)
if err != nil || len(keys) == 0 {
return false, ""
}
case twofa:
twofa, err := GetTwoFactorByUID(u.ID)
if err != nil || twofa == nil {
return false, ""
}
case parentSigned:
gitRepo, err := git.OpenRepository(tmpBasePath)
if err != nil {
return false, ""
}
commit, err := gitRepo.GetCommit(parentCommit)
if err != nil {
return false, ""
}
if commit.Signature == nil {
return false, ""
}
verification := ParseCommitWithSignature(commit)
if !verification.Verified {
return false, ""
}
}
}
return true, signingKey
}
// SignMerge determines if we should sign a merge commit to this repository
func (repo *Repository) SignMerge(u *User, tmpBasePath, baseCommit, headCommit string) (bool, string) {
rules := signingModeFromStrings(setting.Repository.Signing.Merges)
signingKey := signingKey(repo.RepoPath())
if signingKey == "" {
return false, ""
}
var gitRepo *git.Repository
var err error
for _, rule := range rules {
switch rule {
case never:
return false, ""
case always:
break
case pubkey:
keys, err := ListGPGKeys(u.ID)
if err != nil || len(keys) == 0 {
return false, ""
}
case twofa:
twofa, err := GetTwoFactorByUID(u.ID)
if err != nil || twofa == nil {
return false, ""
}
case baseSigned:
if gitRepo == nil {
gitRepo, err = git.OpenRepository(tmpBasePath)
if err != nil {
return false, ""
}
}
commit, err := gitRepo.GetCommit(baseCommit)
if err != nil {
return false, ""
}
verification := ParseCommitWithSignature(commit)
if !verification.Verified {
return false, ""
}
case headSigned:
if gitRepo == nil {
gitRepo, err = git.OpenRepository(tmpBasePath)
if err != nil {
return false, ""
}
}
commit, err := gitRepo.GetCommit(headCommit)
if err != nil {
return false, ""
}
verification := ParseCommitWithSignature(commit)
if !verification.Verified {
return false, ""
}
case commitsSigned:
if gitRepo == nil {
gitRepo, err = git.OpenRepository(tmpBasePath)
if err != nil {
return false, ""
}
}
commit, err := gitRepo.GetCommit(headCommit)
if err != nil {
return false, ""
}
verification := ParseCommitWithSignature(commit)
if !verification.Verified {
return false, ""
}
// need to work out merge-base
mergeBaseCommit, _, err := gitRepo.GetMergeBase("", baseCommit, headCommit)
if err != nil {
return false, ""
}
commitList, err := commit.CommitsBeforeUntil(mergeBaseCommit)
if err != nil {
return false, ""
}
for e := commitList.Front(); e != nil; e = e.Next() {
commit = e.Value.(*git.Commit)
verification := ParseCommitWithSignature(commit)
if !verification.Verified {
return false, ""
}
}
}
}
return true, signingKey
}