Add support for ssh commit signing

go.mod

@@ -11,6 +11,7 @@ require (
 	gitea.com/go-chi/captcha v0.0.0-20211013065431-70641c1a35d5
 	gitea.com/go-chi/session v0.0.0-20211013065435-7d334f340c09
 	gitea.com/lunny/levelqueue v0.4.1
+	github.com/42wim/sshsig v0.0.0-20211121163825-841cf5bbc121
 	github.com/Microsoft/go-winio v0.5.0 // indirect
 	github.com/NYTimes/gziphandler v1.1.1
 	github.com/ProtonMail/go-crypto v0.0.0-20210705153151-cc34b1f6908b // indirect
@@ -122,10 +123,10 @@ require (
 	go.uber.org/atomic v1.9.0 // indirect
 	go.uber.org/multierr v1.7.0 // indirect
 	go.uber.org/zap v1.19.0 // indirect
-	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5
-	golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d
+	golang.org/x/crypto v0.0.0-20211117183948-ae814b36b871
+	golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2
 	golang.org/x/oauth2 v0.0.0-20210628180205-a41e5a781914
-	golang.org/x/sys v0.0.0-20210823070655-63515b42dcdf
+	golang.org/x/sys v0.0.0-20211117180635-dee7805ff2e1
 	golang.org/x/text v0.3.7
 	golang.org/x/time v0.0.0-20210611083556-38a9dc6acbc6 // indirect
 	golang.org/x/tools v0.1.0

go.sum

@@ -54,6 +54,8 @@ gitea.com/lunny/levelqueue v0.4.1 h1:RZ+AFx5gBsZuyqCvofhAkPQ9uaVDPJnsULoJZIYaJNw
 gitea.com/lunny/levelqueue v0.4.1/go.mod h1:HBqmLbz56JWpfEGG0prskAV97ATNRoj5LDmPicD22hU=
 gitea.com/xorm/sqlfiddle v0.0.0-20180821085327-62ce714f951a h1:lSA0F4e9A2NcQSqGqTOXqu2aRi/XEQxDCBwM8yJtE6s=
 gitea.com/xorm/sqlfiddle v0.0.0-20180821085327-62ce714f951a/go.mod h1:EXuID2Zs0pAQhH8yz+DNjUbjppKQzKFAn28TMYPB6IU=
+github.com/42wim/sshsig v0.0.0-20211121163825-841cf5bbc121 h1:r3qt8PCHnfjOv9PN3H+XXKmDA1dfFMIN1AislhlA/ps=
+github.com/42wim/sshsig v0.0.0-20211121163825-841cf5bbc121/go.mod h1:Ock8XgA7pvULhIaHGAk/cDnRfNrF9Jey81nPcc403iU=
 github.com/6543/go-version v1.3.1 h1:HvOp+Telns7HWJ2Xo/05YXQSB2bE0WmVgbHqwMPZT4U=
 github.com/6543/go-version v1.3.1/go.mod h1:oqFAHCwtLVUTLdhQmVZWYvaHXTdsbB4SY85at64SQEo=
 github.com/Azure/go-ntlmssp v0.0.0-20200615164410-66371956d46c h1:/IBSNwUN8+eKzUzbJPqhK839ygXJ82sde8x3ogr6R28=
@@ -1263,6 +1265,8 @@ golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a/go.mod h1:P+XmwS30IXTQdn5
 golang.org/x/crypto v0.0.0-20210616213533-5ff15b29337e/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.0.0-20210817164053-32db794688a5 h1:HWj/xjIHfjYU5nVXpTM0s39J9CbLn7Cc5a7IC5rwsMQ=
 golang.org/x/crypto v0.0.0-20210817164053-32db794688a5/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/crypto v0.0.0-20211117183948-ae814b36b871 h1:/pEO3GD/ABYAjuakUS6xSEmmlyVS4kxBNkeA9tLJiTI=
+golang.org/x/crypto v0.0.0-20211117183948-ae814b36b871/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@@ -1357,6 +1361,8 @@ golang.org/x/net v0.0.0-20210525063256-abc453219eb5/go.mod h1:9nx3DQGgdP8bBQD5qx
 golang.org/x/net v0.0.0-20210614182718-04defd469f4e/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d h1:LO7XpTYMwTqxjLcGWPijK3vRXg1aWdlNOVOHRq45d7c=
 golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2 h1:CIJ76btIcR3eFI5EgSo6k1qKw9KJexJuRLI9G7Hp5wE=
+golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20181106182150-f42d05182288/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -1464,6 +1470,8 @@ golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20210616094352-59db8d763f22/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210823070655-63515b42dcdf h1:2ucpDCmfkl8Bd/FsLtiD653Wf96cW37s+iGx93zsu4k=
 golang.org/x/sys v0.0.0-20210823070655-63515b42dcdf/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211117180635-dee7805ff2e1 h1:kwrAHlwJ0DUBZwQ238v+Uod/3eZ8B2K5rYsUHBQvzmI=
+golang.org/x/sys v0.0.0-20211117180635-dee7805ff2e1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=

models/error.go

@@ -336,6 +336,22 @@ func (err ErrKeyNameAlreadyUsed) Error() string {
 	return fmt.Sprintf("public key already exists [owner_id: %d, name: %s]", err.OwnerID, err.Name)
 }
 
+// ErrSSHInvalidTokenSignature represents a "ErrSSHInvalidTokenSignature" kind of error.
+type ErrSSHInvalidTokenSignature struct {
+	Wrapped     error
+	Fingerprint string
+}
+
+// IsErrSSHInvalidTokenSignature checks if an error is a ErrSSHInvalidTokenSignature.
+func IsErrSSHInvalidTokenSignature(err error) bool {
+	_, ok := err.(ErrSSHInvalidTokenSignature)
+	return ok
+}
+
+func (err ErrSSHInvalidTokenSignature) Error() string {
+	return "the provided signature does not sign the token with the provided key"
+}
+
 // ErrGPGNoEmailFound represents a "ErrGPGNoEmailFound" kind of error.
 type ErrGPGNoEmailFound struct {
 	FailedEmails []string

models/gpg_key_commit_verification.go

@@ -48,6 +48,7 @@ type CommitVerification struct {
 	CommittingUser *User
 	SigningEmail   string
 	SigningKey     *GPGKey
+	SigningSSHKey  *PublicKey
 	TrustStatus    string
 }
 
@@ -121,6 +122,11 @@ func ParseCommitWithSignature(c *git.Commit) *CommitVerification {
 		}
 	}
 
+	// If this a SSH signature handle it differently
+	if strings.Contains(c.Signature.Signature, "SSH") {
+		return ParseCommitWithSSHSignature(c, committer)
+	}
+
 	// Parsing signature
 	sig, err := extractSignature(c.Signature.Signature)
 	if err != nil { // Skipping failed to extract sign
@@ -488,28 +494,31 @@ func CalculateTrustStatus(verification *CommitVerification, repository *Reposito
 		return
 	}
 
-	var isMember bool
-	if keyMap != nil {
-		var has bool
-		isMember, has = (*keyMap)[verification.SigningKey.KeyID]
-		if !has {
+	// Check we actually have a GPG SigningKey
+	if verification.SigningKey != nil {
+		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)
-			(*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.
+		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"
 		}
-	} 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

models/migrations/migrations.go

@@ -357,6 +357,8 @@ var migrations = []Migration{
 	NewMigration("Add table app_state", addTableAppState),
 	// v201 -> v202
 	NewMigration("Drop table remote_version (if exists)", dropTableRemoteVersion),
+	// v202 -> v203
+	NewMigration("Add key is verified to ssh key", addSSHKeyIsVerified),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v202.go

@@ -0,0 +1,15 @@
+// Copyright 2021 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 migrations
+
+import "xorm.io/xorm"
+
+func addSSHKeyIsVerified(x *xorm.Engine) error {
+	type PublicKey struct {
+		Verified bool `xorm:"NOT NULL DEFAULT false"`
+	}
+
+	return x.Sync(new(PublicKey))
+}

models/ssh_key.go

@@ -47,6 +47,7 @@ type PublicKey struct {
 	UpdatedUnix       timeutil.TimeStamp `xorm:"updated"`
 	HasRecentActivity bool               `xorm:"-"`
 	HasUsed           bool               `xorm:"-"`
+	Verified          bool               `xorm:"NOT NULL DEFAULT false"`
 }
 
 func init() {

models/ssh_key_commit_verification.go

@@ -0,0 +1,81 @@
+// Copyright 2021 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 (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"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"
+	"github.com/42wim/sshsig"
+)
+
+// ParseCommitWithSSHSignature check if signature is good against keystore.
+func ParseCommitWithSSHSignature(c *git.Commit, committer *User) *CommitVerification {
+	// Now try to associate the signature with the committer, if present
+	if committer.ID != 0 {
+		keys, err := ListPublicKeys(committer.ID, db.ListOptions{})
+		if err != nil { // Skipping failed to get ssh keys of user
+			log.Error("ListPublicKeys: %v", err)
+			return &CommitVerification{
+				CommittingUser: committer,
+				Verified:       false,
+				Reason:         "gpg.error.failed_retrieval_gpg_keys",
+			}
+		}
+
+		committerEmailAddresses, _ := user_model.GetEmailAddresses(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 {
+			canValidate := false
+			email := ""
+			if k.Verified && activated {
+				canValidate = true
+				email = c.Committer.Email
+			}
+
+			if !canValidate {
+				continue // Skip this key
+			}
+
+			commitVerification := verifySSHCommitVerification(c.Signature.Signature, c.Signature.Payload, k, committer, committer, email)
+			if commitVerification != nil {
+				return commitVerification
+			}
+		}
+	}
+
+	return &CommitVerification{
+		CommittingUser: committer,
+		Verified:       false,
+		Reason:         BadSignature,
+	}
+}
+
+func verifySSHCommitVerification(sig, payload string, k *PublicKey, committer, signer *User, email string) *CommitVerification {
+	if err := sshsig.Verify(bytes.NewBuffer([]byte(payload)), []byte(sig), []byte(k.Content), "git"); err != nil {
+		return nil
+	}
+
+	return &CommitVerification{ // Everything is ok
+		CommittingUser: committer,
+		Verified:       true,
+		Reason:         fmt.Sprintf("%s / %s", signer.Name, k.Fingerprint),
+		SigningUser:    signer,
+		SigningSSHKey:  k,
+		SigningEmail:   email,
+	}
+}

models/ssh_key_verify.go

@@ -0,0 +1,49 @@
+// Copyright 2021 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 (
+	"bytes"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/log"
+	"github.com/42wim/sshsig"
+)
+
+// VerifySSHKey marks a SSH key as verified
+func VerifySSHKey(ownerID int64, fingerprint, token, signature string) (string, error) {
+	ctx, committer, err := db.TxContext()
+	if err != nil {
+		return "", err
+	}
+	defer committer.Close()
+
+	key := new(PublicKey)
+
+	has, err := db.GetEngine(ctx).Where("owner_id = ? AND fingerprint = ?", ownerID, fingerprint).Get(key)
+	if err != nil {
+		return "", err
+	} else if !has {
+		return "", ErrKeyNotExist{}
+	}
+
+	if err := sshsig.Verify(bytes.NewBuffer([]byte(token)), []byte(signature), []byte(key.Content), "gitea"); err != nil {
+		log.Error("Unable to validate token signature. Error: %v", err)
+		return "", ErrSSHInvalidTokenSignature{
+			Fingerprint: key.Fingerprint,
+		}
+	}
+
+	key.Verified = true
+	if _, err := db.GetEngine(ctx).ID(key.ID).SetExpr("verified", true).Update(new(PublicKey)); err != nil {
+		return "", err
+	}
+
+	if err := committer.Commit(); err != nil {
+		return "", err
+	}
+
+	return key.Fingerprint, nil
+}

options/locale/locale_en-US.ini

@@ -620,6 +620,17 @@ gpg_token_code = echo "%s" | gpg -a --default-key %s --detach-sig
 gpg_token_signature = Armored GPG signature
 key_signature_gpg_placeholder = Begins with '-----BEGIN PGP SIGNATURE-----'
 verify_gpg_key_success = The GPG key '%s' has been verified.
+ssh_key_verified=Verified Key
+ssh_key_verified_long=Key has been verified with a token and can be used to verify commits matching any activated email addresses for this user.
+ssh_key_verify=Verify
+ssh_invalid_token_signature = The provided SSH key, signature and token do not match or token is out-of-date.
+ssh_token_required = You must provide a signature for the below token
+ssh_token = Token
+ssh_token_help = You can generate a signature using:
+ssh_token_code = echo -n "%s" |ssh-keygen -Y sign -n gitea -f /path_to_your_pubkey
+gpg_token_signature = Armored SSH signature
+key_signature_ssh_placeholder = Begins with '-----BEGIN SSH SIGNATURE-----'
+verify_ssh_key_success = The SSH key '%s' has been verified.
 subkeys = Subkeys
 key_id = Key ID
 key_name = Key Name
@@ -1071,6 +1082,7 @@ commits.signed_by = Signed by
 commits.signed_by_untrusted_user = Signed by untrusted user
 commits.signed_by_untrusted_user_unmatched = Signed by untrusted user who does not match committer
 commits.gpg_key_id = GPG Key ID
+commits.ssh_key_fingerprint = SSH Key Fingerprint
 
 ext_issues = Ext. Issues
 ext_issues.desc = Link to an external issue tracker.

routers/web/user/setting/keys.go

@@ -183,6 +183,28 @@ func KeysPost(ctx *context.Context) {
 		}
 		ctx.Flash.Success(ctx.Tr("settings.add_key_success", form.Title))
 		ctx.Redirect(setting.AppSubURL + "/user/settings/keys")
+	case "verify_ssh":
+		token := models.VerificationToken(ctx.User, 1)
+		lastToken := models.VerificationToken(ctx.User, 0)
+
+		fingerprint, err := models.VerifySSHKey(ctx.User.ID, form.Fingerprint, token, form.Signature)
+		if err != nil && models.IsErrSSHInvalidTokenSignature(err) {
+			fingerprint, err = models.VerifySSHKey(ctx.User.ID, form.Fingerprint, lastToken, form.Signature)
+		}
+		if err != nil {
+			ctx.Data["HasSSHVerifyError"] = true
+			switch {
+			case models.IsErrSSHInvalidTokenSignature(err):
+				loadKeysData(ctx)
+				ctx.Data["Err_Signature"] = true
+				ctx.Data["Fingerprint"] = err.(models.ErrSSHInvalidTokenSignature).Fingerprint
+				ctx.RenderWithErr(ctx.Tr("settings.ssh_invalid_token_signature"), tplSettingsKeys, &form)
+			default:
+				ctx.ServerError("VerifySSH", err)
+			}
+		}
+		ctx.Flash.Success(ctx.Tr("settings.verify_ssh_key_success", fingerprint))
+		ctx.Redirect(setting.AppSubURL + "/user/settings/keys")
 
 	default:
 		ctx.Flash.Warning("Function not implemented")
@@ -267,4 +289,5 @@ func loadKeysData(ctx *context.Context) {
 	ctx.Data["Principals"] = principals
 
 	ctx.Data["VerifyingID"] = ctx.FormString("verify_gpg")
+	ctx.Data["VerifyingFingerprint"] = ctx.FormString("verify_ssh")
 }

services/forms/user_form.go

@@ -344,12 +344,13 @@ func (f *AddOpenIDForm) Validate(req *http.Request, errs binding.Errors) binding
 
 // AddKeyForm form for adding SSH/GPG key
 type AddKeyForm struct {
-	Type       string `binding:"OmitEmpty"`
-	Title      string `binding:"Required;MaxSize(50)"`
-	Content    string `binding:"Required"`
-	Signature  string `binding:"OmitEmpty"`
-	KeyID      string `binding:"OmitEmpty"`
-	IsWritable bool
+	Type        string `binding:"OmitEmpty"`
+	Title       string `binding:"Required;MaxSize(50)"`
+	Content     string `binding:"Required"`
+	Signature   string `binding:"OmitEmpty"`
+	KeyID       string `binding:"OmitEmpty"`
+	Fingerprint string `binding:"OmitEmpty"`
+	IsWritable  bool
 }
 
 // Validate validates the fields