Use go method to calculate ssh key fingerprint (#7128)

* Use go method to calculate key fingerprint

* add gitea copyright

* use native go method only for built-in server

* refactor and add tests

* add gitea copyright

1 files changed, 30 insertions, 1 deletions

diff --git a/models/ssh_key.go b/models/ssh_key.go
index 1f2288b13e..15a10826d8 100644
--- a/models/ssh_key.go
+++ b/models/ssh_key.go
@@ -1,4 +1,5 @@
 // Copyright 2014 The Gogs Authors. All rights reserved.
+// 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.
 
@@ -359,7 +360,7 @@ func checkKeyFingerprint(e Engine, fingerprint string) error {
 	return nil
 }
 
-func calcFingerprint(publicKeyContent string) (string, error) {
+func calcFingerprintSSHKeygen(publicKeyContent string) (string, error) {
 	// Calculate fingerprint.
 	tmpPath, err := writeTmpKeyFile(publicKeyContent)
 	if err != nil {
@@ -375,6 +376,34 @@ func calcFingerprint(publicKeyContent string) (string, error) {
 	return strings.Split(stdout, " ")[1], nil
 }
 
+func calcFingerprintNative(publicKeyContent string) (string, error) {
+	// Calculate fingerprint.
+	pk, _, _, _, err := ssh.ParseAuthorizedKey([]byte(publicKeyContent))
+	if err != nil {
+		return "", err
+	}
+	return ssh.FingerprintSHA256(pk), nil
+}
+
+func calcFingerprint(publicKeyContent string) (string, error) {
+	//Call the method based on configuration
+	var (
+		fnName, fp string
+		err        error
+	)
+	if setting.SSH.StartBuiltinServer {
+		fnName = "calcFingerprintNative"
+		fp, err = calcFingerprintNative(publicKeyContent)
+	} else {
+		fnName = "calcFingerprintSSHKeygen"
+		fp, err = calcFingerprintSSHKeygen(publicKeyContent)
+	}
+	if err != nil {
+		return "", fmt.Errorf("%s: %v", fnName, err)
+	}
+	return fp, nil
+}
+
 func addKey(e Engine, key *PublicKey) (err error) {
 	if len(key.Fingerprint) == 0 {
 		key.Fingerprint, err = calcFingerprint(key.Content)