Merge pull request 'Allow pushmirror to use publickey authentication' (#4819) from ironmagma/forgejo:publickey-auth-push-mirror into forgejo

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/4819
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>

.deadcode-out

@@ -170,11 +170,6 @@ code.gitea.io/gitea/modules/json
 	StdJSON.NewDecoder
 	StdJSON.Indent
 
-code.gitea.io/gitea/modules/keying
-	DeriveKey
-	Key.Encrypt
-	Key.Decrypt
-
 code.gitea.io/gitea/modules/markup
 	GetRendererByType
 	RenderString

models/forgejo_migrations/migrate.go

@@ -78,6 +78,8 @@ var migrations = []*Migration{
 	NewMigration("Add external_url to attachment table", AddExternalURLColumnToAttachmentTable),
 	// v20 -> v21
 	NewMigration("Creating Quota-related tables", CreateQuotaTables),
+	// v21 -> v22
+	NewMigration("Add SSH keypair to `pull_mirror` table", AddSSHKeypairToPushMirror),
 }
 
 // GetCurrentDBVersion returns the current Forgejo database version.

models/forgejo_migrations/v21.go

@@ -0,0 +1,16 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgejo_migrations //nolint:revive
+
+import "xorm.io/xorm"
+
+func AddSSHKeypairToPushMirror(x *xorm.Engine) error {
+	type PushMirror struct {
+		ID         int64  `xorm:"pk autoincr"`
+		PublicKey  string `xorm:"VARCHAR(100)"`
+		PrivateKey []byte `xorm:"BLOB"`
+	}
+
+	return x.Sync(&PushMirror{})
+}

models/repo/pushmirror.go

@@ -13,6 +13,7 @@ import (
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/modules/git"
 	giturl "code.gitea.io/gitea/modules/git/url"
+	"code.gitea.io/gitea/modules/keying"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
@@ -32,6 +33,10 @@ type PushMirror struct {
 	RemoteName    string
 	RemoteAddress string `xorm:"VARCHAR(2048)"`
 
+	// A keypair formatted in OpenSSH format.
+	PublicKey  string `xorm:"VARCHAR(100)"`
+	PrivateKey []byte `xorm:"BLOB"`
+
 	SyncOnCommit   bool `xorm:"NOT NULL DEFAULT true"`
 	Interval       time.Duration
 	CreatedUnix    timeutil.TimeStamp `xorm:"created"`
@@ -82,6 +87,29 @@ func (m *PushMirror) GetRemoteName() string {
 	return m.RemoteName
 }
 
+// GetPublicKey returns a sanitized version of the public key.
+// This should only be used when displaying the public key to the user, not for actual code.
+func (m *PushMirror) GetPublicKey() string {
+	return strings.TrimSuffix(m.PublicKey, "\n")
+}
+
+// SetPrivatekey encrypts the given private key and store it in the database.
+// The ID of the push mirror must be known, so this should be done after the
+// push mirror is inserted.
+func (m *PushMirror) SetPrivatekey(ctx context.Context, privateKey []byte) error {
+	key := keying.DeriveKey(keying.ContextPushMirror)
+	m.PrivateKey = key.Encrypt(privateKey, keying.ColumnAndID("private_key", m.ID))
+
+	_, err := db.GetEngine(ctx).ID(m.ID).Cols("private_key").Update(m)
+	return err
+}
+
+// Privatekey retrieves the encrypted private key and decrypts it.
+func (m *PushMirror) Privatekey() ([]byte, error) {
+	key := keying.DeriveKey(keying.ContextPushMirror)
+	return key.Decrypt(m.PrivateKey, keying.ColumnAndID("private_key", m.ID))
+}
+
 // UpdatePushMirror updates the push-mirror
 func UpdatePushMirror(ctx context.Context, m *PushMirror) error {
 	_, err := db.GetEngine(ctx).ID(m.ID).AllCols().Update(m)

models/repo/pushmirror_test.go

@@ -50,3 +50,30 @@ func TestPushMirrorsIterate(t *testing.T) {
 		return nil
 	})
 }
+
+func TestPushMirrorPrivatekey(t *testing.T) {
+	require.NoError(t, unittest.PrepareTestDatabase())
+
+	m := &repo_model.PushMirror{
+		RemoteName: "test-privatekey",
+	}
+	require.NoError(t, db.Insert(db.DefaultContext, m))
+
+	privateKey := []byte{0x00, 0x01, 0x02, 0x04, 0x08, 0x10}
+	t.Run("Set privatekey", func(t *testing.T) {
+		require.NoError(t, m.SetPrivatekey(db.DefaultContext, privateKey))
+	})
+
+	t.Run("Normal retrieval", func(t *testing.T) {
+		actualPrivateKey, err := m.Privatekey()
+		require.NoError(t, err)
+		assert.EqualValues(t, privateKey, actualPrivateKey)
+	})
+
+	t.Run("Incorrect retrieval", func(t *testing.T) {
+		m.ID++
+		actualPrivateKey, err := m.Privatekey()
+		require.Error(t, err)
+		assert.Empty(t, actualPrivateKey)
+	})
+}

modules/git/repo.go

@@ -1,5 +1,6 @@
 // Copyright 2015 The Gogs Authors. All rights reserved.
 // Copyright 2017 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package git
@@ -18,6 +19,7 @@ import (
 	"time"
 
 	"code.gitea.io/gitea/modules/proxy"
+	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
 )
 
@@ -196,11 +198,33 @@ type PushOptions struct {
 	Mirror         bool
 	Env            []string
 	Timeout        time.Duration
+	PrivateKeyPath string
 }
 
 // Push pushs local commits to given remote branch.
 func Push(ctx context.Context, repoPath string, opts PushOptions) error {
 	cmd := NewCommand(ctx, "push")
+
+	if opts.PrivateKeyPath != "" {
+		// Preserve the behavior that existing environments are used if no
+		// environments are passed.
+		if len(opts.Env) == 0 {
+			opts.Env = os.Environ()
+		}
+
+		// Use environment because it takes precedence over using -c core.sshcommand
+		// and it's possible that a system might have an existing GIT_SSH_COMMAND
+		// environment set.
+		opts.Env = append(opts.Env, "GIT_SSH_COMMAND=ssh"+
+			fmt.Sprintf(` -i %s`, opts.PrivateKeyPath)+
+			" -o IdentitiesOnly=yes"+
+			// This will store new SSH host keys and verify connections to existing
+			// host keys, but it doesn't allow replacement of existing host keys. This
+			// means TOFU is used for Git over SSH pushes.
+			" -o StrictHostKeyChecking=accept-new"+
+			" -o UserKnownHostsFile="+filepath.Join(setting.SSH.RootPath, "known_hosts"))
+	}
+
 	if opts.Force {
 		cmd.AddArguments("-f")
 	}

modules/keying/keying.go

@@ -18,6 +18,7 @@ package keying
 import (
 	"crypto/rand"
 	"crypto/sha256"
+	"encoding/binary"
 
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/crypto/hkdf"
@@ -44,6 +45,9 @@ func Init(ikm []byte) {
 // This must be a hardcoded string and must not be arbitrarily constructed.
 type Context string
 
+// Used for the `push_mirror` table.
+var ContextPushMirror Context = "pushmirror"
+
 // Derive *the* key for a given context, this is a determistic function. The
 // same key will be provided for the same context.
 func DeriveKey(context Context) *Key {
@@ -109,3 +113,13 @@ func (k *Key) Decrypt(ciphertext, additionalData []byte) ([]byte, error) {
 
 	return e.Open(nil, nonce, ciphertext, additionalData)
 }
+
+// ColumnAndID generates a context that can be used as additional context for
+// encrypting and decrypting data. It requires the column name and the row ID
+// (this requires to be known beforehand). Be careful when using this, as the
+// table name isn't part of this context. This means it's not bound to a
+// particular table. The table should be part of the context that the key was
+// derived for, in which case it binds through that.
+func ColumnAndID(column string, id int64) []byte {
+	return binary.BigEndian.AppendUint64(append([]byte(column), ':'), uint64(id))
+}

modules/keying/keying_test.go

@@ -4,6 +4,7 @@
 package keying_test
 
 import (
+	"math"
 	"testing"
 
 	"code.gitea.io/gitea/modules/keying"
@@ -94,3 +95,17 @@ func TestKeying(t *testing.T) {
 		})
 	})
 }
+
+func TestKeyingColumnAndID(t *testing.T) {
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x3a, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, keying.ColumnAndID("table", math.MinInt64))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x3a, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, keying.ColumnAndID("table", -1))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x3a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, keying.ColumnAndID("table", 0))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x3a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}, keying.ColumnAndID("table", 1))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x3a, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, keying.ColumnAndID("table", math.MaxInt64))
+
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x32, 0x3a, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, keying.ColumnAndID("table2", math.MinInt64))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x32, 0x3a, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, keying.ColumnAndID("table2", -1))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x32, 0x3a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, keying.ColumnAndID("table2", 0))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x32, 0x3a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}, keying.ColumnAndID("table2", 1))
+	assert.EqualValues(t, []byte{0x74, 0x61, 0x62, 0x6c, 0x65, 0x32, 0x3a, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, keying.ColumnAndID("table2", math.MaxInt64))
+}

modules/lfs/endpoint.go

@@ -60,6 +60,10 @@ func endpointFromURL(rawurl string) *url.URL {
 	case "git":
 		u.Scheme = "https"
 		return u
+	case "ssh":
+		u.Scheme = "https"
+		u.User = nil
+		return u
 	case "file":
 		return u
 	default:

modules/structs/mirror.go

@@ -12,6 +12,7 @@ type CreatePushMirrorOption struct {
 	RemotePassword string `json:"remote_password"`
 	Interval       string `json:"interval"`
 	SyncOnCommit   bool   `json:"sync_on_commit"`
+	UseSSH         bool   `json:"use_ssh"`
 }
 
 // PushMirror represents information of a push mirror
@@ -27,4 +28,5 @@ type PushMirror struct {
 	LastError      string     `json:"last_error"`
 	Interval       string     `json:"interval"`
 	SyncOnCommit   bool       `json:"sync_on_commit"`
+	PublicKey      string     `json:"public_key"`
 }

modules/util/util.go

@@ -1,11 +1,14 @@
 // Copyright 2017 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package util
 
 import (
 	"bytes"
+	"crypto/ed25519"
 	"crypto/rand"
+	"encoding/pem"
 	"fmt"
 	"math/big"
 	"strconv"
@@ -13,6 +16,7 @@ import (
 
 	"code.gitea.io/gitea/modules/optional"
 
+	"golang.org/x/crypto/ssh"
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
 )
@@ -229,3 +233,23 @@ func ReserveLineBreakForTextarea(input string) string {
 	// Other than this, we should respect the original content, even leading or trailing spaces.
 	return strings.ReplaceAll(input, "\r\n", "\n")
 }
+
+// GenerateSSHKeypair generates a ed25519 SSH-compatible keypair.
+func GenerateSSHKeypair() (publicKey, privateKey []byte, err error) {
+	public, private, err := ed25519.GenerateKey(nil)
+	if err != nil {
+		return nil, nil, fmt.Errorf("ed25519.GenerateKey: %w", err)
+	}
+
+	privPEM, err := ssh.MarshalPrivateKey(private, "")
+	if err != nil {
+		return nil, nil, fmt.Errorf("ssh.MarshalPrivateKey: %w", err)
+	}
+
+	sshPublicKey, err := ssh.NewPublicKey(public)
+	if err != nil {
+		return nil, nil, fmt.Errorf("ssh.NewPublicKey: %w", err)
+	}
+
+	return ssh.MarshalAuthorizedKey(sshPublicKey), pem.EncodeToMemory(privPEM), nil
+}

modules/util/util_test.go

@@ -1,14 +1,19 @@
 // Copyright 2018 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
-package util
+package util_test
 
 import (
+	"bytes"
+	"crypto/rand"
 	"regexp"
 	"strings"
 	"testing"
 
 	"code.gitea.io/gitea/modules/optional"
+	"code.gitea.io/gitea/modules/test"
+	"code.gitea.io/gitea/modules/util"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -43,7 +48,7 @@ func TestURLJoin(t *testing.T) {
 		newTest("/a/b/c#hash",
 			"/a", "b/c#hash"),
 	} {
-		assert.Equal(t, test.Expected, URLJoin(test.Base, test.Elements...))
+		assert.Equal(t, test.Expected, util.URLJoin(test.Base, test.Elements...))
 	}
 }
 
@@ -59,7 +64,7 @@ func TestIsEmptyString(t *testing.T) {
 	}
 
 	for _, v := range cases {
-		assert.Equal(t, v.expected, IsEmptyString(v.s))
+		assert.Equal(t, v.expected, util.IsEmptyString(v.s))
 	}
 }
 
@@ -100,42 +105,42 @@ func Test_NormalizeEOL(t *testing.T) {
 	unix := buildEOLData(data1, "\n")
 	mac := buildEOLData(data1, "\r")
 
-	assert.Equal(t, unix, NormalizeEOL(dos))
+	assert.Equal(t, unix, util.NormalizeEOL(dos))
-	assert.Equal(t, unix, NormalizeEOL(mac))
+	assert.Equal(t, unix, util.NormalizeEOL(mac))
-	assert.Equal(t, unix, NormalizeEOL(unix))
+	assert.Equal(t, unix, util.NormalizeEOL(unix))
 
 	dos = buildEOLData(data2, "\r\n")
 	unix = buildEOLData(data2, "\n")
 	mac = buildEOLData(data2, "\r")
 
-	assert.Equal(t, unix, NormalizeEOL(dos))
+	assert.Equal(t, unix, util.NormalizeEOL(dos))
-	assert.Equal(t, unix, NormalizeEOL(mac))
+	assert.Equal(t, unix, util.NormalizeEOL(mac))
-	assert.Equal(t, unix, NormalizeEOL(unix))
+	assert.Equal(t, unix, util.NormalizeEOL(unix))
 
-	assert.Equal(t, []byte("one liner"), NormalizeEOL([]byte("one liner")))
+	assert.Equal(t, []byte("one liner"), util.NormalizeEOL([]byte("one liner")))
-	assert.Equal(t, []byte("\n"), NormalizeEOL([]byte("\n")))
+	assert.Equal(t, []byte("\n"), util.NormalizeEOL([]byte("\n")))
-	assert.Equal(t, []byte("\ntwo liner"), NormalizeEOL([]byte("\ntwo liner")))
+	assert.Equal(t, []byte("\ntwo liner"), util.NormalizeEOL([]byte("\ntwo liner")))
-	assert.Equal(t, []byte("two liner\n"), NormalizeEOL([]byte("two liner\n")))
+	assert.Equal(t, []byte("two liner\n"), util.NormalizeEOL([]byte("two liner\n")))
-	assert.Equal(t, []byte{}, NormalizeEOL([]byte{}))
+	assert.Equal(t, []byte{}, util.NormalizeEOL([]byte{}))
 
-	assert.Equal(t, []byte("mix\nand\nmatch\n."), NormalizeEOL([]byte("mix\r\nand\rmatch\n.")))
+	assert.Equal(t, []byte("mix\nand\nmatch\n."), util.NormalizeEOL([]byte("mix\r\nand\rmatch\n.")))
 }
 
 func Test_RandomInt(t *testing.T) {
-	randInt, err := CryptoRandomInt(255)
+	randInt, err := util.CryptoRandomInt(255)
 	assert.GreaterOrEqual(t, randInt, int64(0))
 	assert.LessOrEqual(t, randInt, int64(255))
 	require.NoError(t, err)
 }
 
 func Test_RandomString(t *testing.T) {
-	str1, err := CryptoRandomString(32)
+	str1, err := util.CryptoRandomString(32)
 	require.NoError(t, err)
 	matches, err := regexp.MatchString(`^[a-zA-Z0-9]{32}$`, str1)
 	require.NoError(t, err)
 	assert.True(t, matches)
 
-	str2, err := CryptoRandomString(32)
+	str2, err := util.CryptoRandomString(32)
 	require.NoError(t, err)
 	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{32}$`, str1)
 	require.NoError(t, err)
@@ -143,13 +148,13 @@ func Test_RandomString(t *testing.T) {
 
 	assert.NotEqual(t, str1, str2)
 
-	str3, err := CryptoRandomString(256)
+	str3, err := util.CryptoRandomString(256)
 	require.NoError(t, err)
 	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{256}$`, str3)
 	require.NoError(t, err)
 	assert.True(t, matches)
 
-	str4, err := CryptoRandomString(256)
+	str4, err := util.CryptoRandomString(256)
 	require.NoError(t, err)
 	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{256}$`, str4)
 	require.NoError(t, err)
@@ -159,34 +164,34 @@ func Test_RandomString(t *testing.T) {
 }
 
 func Test_RandomBytes(t *testing.T) {
-	bytes1, err := CryptoRandomBytes(32)
+	bytes1, err := util.CryptoRandomBytes(32)
 	require.NoError(t, err)
 
-	bytes2, err := CryptoRandomBytes(32)
+	bytes2, err := util.CryptoRandomBytes(32)
 	require.NoError(t, err)
 
 	assert.NotEqual(t, bytes1, bytes2)
 
-	bytes3, err := CryptoRandomBytes(256)
+	bytes3, err := util.CryptoRandomBytes(256)
 	require.NoError(t, err)
 
-	bytes4, err := CryptoRandomBytes(256)
+	bytes4, err := util.CryptoRandomBytes(256)
 	require.NoError(t, err)
 
 	assert.NotEqual(t, bytes3, bytes4)
 }
 
 func TestOptionalBoolParse(t *testing.T) {
-	assert.Equal(t, optional.None[bool](), OptionalBoolParse(""))
+	assert.Equal(t, optional.None[bool](), util.OptionalBoolParse(""))
-	assert.Equal(t, optional.None[bool](), OptionalBoolParse("x"))
+	assert.Equal(t, optional.None[bool](), util.OptionalBoolParse("x"))
 
-	assert.Equal(t, optional.Some(false), OptionalBoolParse("0"))
+	assert.Equal(t, optional.Some(false), util.OptionalBoolParse("0"))
-	assert.Equal(t, optional.Some(false), OptionalBoolParse("f"))
+	assert.Equal(t, optional.Some(false), util.OptionalBoolParse("f"))
-	assert.Equal(t, optional.Some(false), OptionalBoolParse("False"))
+	assert.Equal(t, optional.Some(false), util.OptionalBoolParse("False"))
 
-	assert.Equal(t, optional.Some(true), OptionalBoolParse("1"))
+	assert.Equal(t, optional.Some(true), util.OptionalBoolParse("1"))
-	assert.Equal(t, optional.Some(true), OptionalBoolParse("t"))
+	assert.Equal(t, optional.Some(true), util.OptionalBoolParse("t"))
-	assert.Equal(t, optional.Some(true), OptionalBoolParse("True"))
+	assert.Equal(t, optional.Some(true), util.OptionalBoolParse("True"))
 }
 
 // Test case for any function which accepts and returns a single string.
@@ -209,7 +214,7 @@ var upperTests = []StringTest{
 
 func TestToUpperASCII(t *testing.T) {
 	for _, tc := range upperTests {
-		assert.Equal(t, ToUpperASCII(tc.in), tc.out)
+		assert.Equal(t, util.ToUpperASCII(tc.in), tc.out)
 	}
 }
 
@@ -217,27 +222,56 @@ func BenchmarkToUpper(b *testing.B) {
 	for _, tc := range upperTests {
 		b.Run(tc.in, func(b *testing.B) {
 			for i := 0; i < b.N; i++ {
-				ToUpperASCII(tc.in)
+				util.ToUpperASCII(tc.in)
 			}
 		})
 	}
 }
 
 func TestToTitleCase(t *testing.T) {
-	assert.Equal(t, `Foo Bar Baz`, ToTitleCase(`foo bar baz`))
+	assert.Equal(t, `Foo Bar Baz`, util.ToTitleCase(`foo bar baz`))
-	assert.Equal(t, `Foo Bar Baz`, ToTitleCase(`FOO BAR BAZ`))
+	assert.Equal(t, `Foo Bar Baz`, util.ToTitleCase(`FOO BAR BAZ`))
 }
 
 func TestToPointer(t *testing.T) {
-	assert.Equal(t, "abc", *ToPointer("abc"))
+	assert.Equal(t, "abc", *util.ToPointer("abc"))
-	assert.Equal(t, 123, *ToPointer(123))
+	assert.Equal(t, 123, *util.ToPointer(123))
 	abc := "abc"
-	assert.NotSame(t, &abc, ToPointer(abc))
+	assert.NotSame(t, &abc, util.ToPointer(abc))
 	val123 := 123
-	assert.NotSame(t, &val123, ToPointer(val123))
+	assert.NotSame(t, &val123, util.ToPointer(val123))
 }
 
 func TestReserveLineBreakForTextarea(t *testing.T) {
-	assert.Equal(t, "test\ndata", ReserveLineBreakForTextarea("test\r\ndata"))
+	assert.Equal(t, "test\ndata", util.ReserveLineBreakForTextarea("test\r\ndata"))
-	assert.Equal(t, "test\ndata\n", ReserveLineBreakForTextarea("test\r\ndata\r\n"))
+	assert.Equal(t, "test\ndata\n", util.ReserveLineBreakForTextarea("test\r\ndata\r\n"))
+}
+
+const (
+	testPublicKey  = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAOhB7/zzhC+HXDdGOdLwJln5NYwm6UNXx3chmQSVTG4\n"
+	testPrivateKey = `-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtz
+c2gtZWQyNTUxOQAAACADoQe/884Qvh1w3RjnS8CZZ+TWMJulDV8d3IZkElUxuAAA
+AIggISIjICEiIwAAAAtzc2gtZWQyNTUxOQAAACADoQe/884Qvh1w3RjnS8CZZ+TW
+MJulDV8d3IZkElUxuAAAAEAAAQIDBAUGBwgJCgsMDQ4PEBESExQVFhcYGRobHB0e
+HwOhB7/zzhC+HXDdGOdLwJln5NYwm6UNXx3chmQSVTG4AAAAAAECAwQF
+-----END OPENSSH PRIVATE KEY-----` + "\n"
+)
+
+func TestGeneratingEd25519Keypair(t *testing.T) {
+	defer test.MockProtect(&rand.Reader)()
+
+	// Only 32 bytes needs to be provided to generate a ed25519 keypair.
+	// And another 32 bytes are required, which is included as random value
+	// in the OpenSSH format.
+	b := make([]byte, 64)
+	for i := 0; i < 64; i++ {
+		b[i] = byte(i)
+	}
+	rand.Reader = bytes.NewReader(b)
+
+	publicKey, privateKey, err := util.GenerateSSHKeypair()
+	require.NoError(t, err)
+	assert.EqualValues(t, testPublicKey, string(publicKey))
+	assert.EqualValues(t, testPrivateKey, string(privateKey))
 }

options/locale/locale_en-US.ini

@@ -1102,6 +1102,10 @@ mirror_prune = Prune
 mirror_prune_desc = Remove obsolete remote-tracking references
 mirror_interval = Mirror interval (valid time units are "h", "m", "s"). 0 to disable periodic sync. (Minimum interval: %s)
 mirror_interval_invalid = The mirror interval is not valid.
+mirror_public_key = Public SSH key
+mirror_use_ssh.text = Use SSH authentication
+mirror_use_ssh.helper = Forgejo will mirror the repository via Git over SSH and create a keypair for you when you select this option. You must ensure that the generated public key is authorized to push to the destination repository. You cannot use password-based authorization when selecting this.
+mirror_denied_combination = Cannot use public key and password based authentication in combination.
 mirror_sync = synced
 mirror_sync_on_commit = Sync when commits are pushed
 mirror_address = Clone from URL
@@ -2177,12 +2181,14 @@ settings.mirror_settings.push_mirror.none = No push mirrors configured
 settings.mirror_settings.push_mirror.remote_url = Git remote repository URL
 settings.mirror_settings.push_mirror.add = Add push mirror
 settings.mirror_settings.push_mirror.edit_sync_time = Edit mirror sync interval
+settings.mirror_settings.push_mirror.none = None
 
 settings.units.units = Repository units
 settings.units.overview = Overview
 settings.units.add_more = Add more...
 
 settings.sync_mirror = Synchronize now
+settings.mirror_settings.push_mirror.copy_public_key = Copy public key
 settings.pull_mirror_sync_in_progress = Pulling changes from the remote %s at the moment.
 settings.pull_mirror_sync_quota_exceeded = Quota exceeded, not pulling changes.
 settings.push_mirror_sync_in_progress = Pushing changes to the remote %s at the moment.

release-notes/4819.md

@@ -0,0 +1 @@
+Allow push mirrors to use a SSH key as the authentication method for the mirroring action instead of using user:password authentication. The SSH keypair is created by Forgejo and the destination repository must be configured with the public key to allow for push over SSH.

routers/api/v1/repo/mirror.go

@@ -350,6 +350,11 @@ func CreatePushMirror(ctx *context.APIContext, mirrorOption *api.CreatePushMirro
 		return
 	}
 
+	if mirrorOption.UseSSH && (mirrorOption.RemoteUsername != "" || mirrorOption.RemotePassword != "") {
+		ctx.Error(http.StatusBadRequest, "CreatePushMirror", "'use_ssh' is mutually exclusive with 'remote_username' and 'remote_passoword'")
+		return
+	}
+
 	address, err := forms.ParseRemoteAddr(mirrorOption.RemoteAddress, mirrorOption.RemoteUsername, mirrorOption.RemotePassword)
 	if err == nil {
 		err = migrations.IsMigrateURLAllowed(address, ctx.ContextUser)
@@ -365,7 +370,7 @@ func CreatePushMirror(ctx *context.APIContext, mirrorOption *api.CreatePushMirro
 		return
 	}
 
-	remoteAddress, err := util.SanitizeURL(mirrorOption.RemoteAddress)
+	remoteAddress, err := util.SanitizeURL(address)
 	if err != nil {
 		ctx.ServerError("SanitizeURL", err)
 		return
@@ -380,11 +385,29 @@ func CreatePushMirror(ctx *context.APIContext, mirrorOption *api.CreatePushMirro
 		RemoteAddress: remoteAddress,
 	}
 
+	var plainPrivateKey []byte
+	if mirrorOption.UseSSH {
+		publicKey, privateKey, err := util.GenerateSSHKeypair()
+		if err != nil {
+			ctx.ServerError("GenerateSSHKeypair", err)
+			return
+		}
+		plainPrivateKey = privateKey
+		pushMirror.PublicKey = string(publicKey)
+	}
+
 	if err = db.Insert(ctx, pushMirror); err != nil {
 		ctx.ServerError("InsertPushMirror", err)
 		return
 	}
 
+	if mirrorOption.UseSSH {
+		if err = pushMirror.SetPrivatekey(ctx, plainPrivateKey); err != nil {
+			ctx.ServerError("SetPrivatekey", err)
+			return
+		}
+	}
+
 	// if the registration of the push mirrorOption fails remove it from the database
 	if err = mirror_service.AddPushMirrorRemote(ctx, pushMirror, address); err != nil {
 		if err := repo_model.DeletePushMirrors(ctx, repo_model.PushMirrorOptions{ID: pushMirror.ID, RepoID: pushMirror.RepoID}); err != nil {

routers/web/repo/setting/setting.go

@@ -478,8 +478,7 @@ func SettingsPost(ctx *context.Context) {
 			ctx.ServerError("UpdateAddress", err)
 			return
 		}
-
+		remoteAddress, err := util.SanitizeURL(address)
-		remoteAddress, err := util.SanitizeURL(form.MirrorAddress)
 		if err != nil {
 			ctx.ServerError("SanitizeURL", err)
 			return
@@ -638,6 +637,12 @@ func SettingsPost(ctx *context.Context) {
 			return
 		}
 
+		if form.PushMirrorUseSSH && (form.PushMirrorUsername != "" || form.PushMirrorPassword != "") {
+			ctx.Data["Err_PushMirrorUseSSH"] = true
+			ctx.RenderWithErr(ctx.Tr("repo.mirror_denied_combination"), tplSettingsOptions, &form)
+			return
+		}
+
 		address, err := forms.ParseRemoteAddr(form.PushMirrorAddress, form.PushMirrorUsername, form.PushMirrorPassword)
 		if err == nil {
 			err = migrations.IsMigrateURLAllowed(address, ctx.Doer)
@@ -654,7 +659,7 @@ func SettingsPost(ctx *context.Context) {
 			return
 		}
 
-		remoteAddress, err := util.SanitizeURL(form.PushMirrorAddress)
+		remoteAddress, err := util.SanitizeURL(address)
 		if err != nil {
 			ctx.ServerError("SanitizeURL", err)
 			return
@@ -668,11 +673,30 @@ func SettingsPost(ctx *context.Context) {
 			Interval:      interval,
 			RemoteAddress: remoteAddress,
 		}
+
+		var plainPrivateKey []byte
+		if form.PushMirrorUseSSH {
+			publicKey, privateKey, err := util.GenerateSSHKeypair()
+			if err != nil {
+				ctx.ServerError("GenerateSSHKeypair", err)
+				return
+			}
+			plainPrivateKey = privateKey
+			m.PublicKey = string(publicKey)
+		}
+
 		if err := db.Insert(ctx, m); err != nil {
 			ctx.ServerError("InsertPushMirror", err)
 			return
 		}
 
+		if form.PushMirrorUseSSH {
+			if err := m.SetPrivatekey(ctx, plainPrivateKey); err != nil {
+				ctx.ServerError("SetPrivatekey", err)
+				return
+			}
+		}
+
 		if err := mirror_service.AddPushMirrorRemote(ctx, m, address); err != nil {
 			if err := repo_model.DeletePushMirrors(ctx, repo_model.PushMirrorOptions{ID: m.ID, RepoID: m.RepoID}); err != nil {
 				log.Error("DeletePushMirrors %v", err)

services/convert/mirror.go

@@ -22,5 +22,6 @@ func ToPushMirror(ctx context.Context, pm *repo_model.PushMirror) (*api.PushMirr
 		LastError:      pm.LastError,
 		Interval:       pm.Interval.String(),
 		SyncOnCommit:   pm.SyncOnCommit,
+		PublicKey:      pm.GetPublicKey(),
 	}, nil
 }

services/forms/repo_form.go

@@ -6,8 +6,10 @@
 package forms
 
 import (
+	"fmt"
 	"net/http"
 	"net/url"
+	"regexp"
 	"strings"
 
 	"code.gitea.io/gitea/models"
@@ -88,6 +90,9 @@ func (f *MigrateRepoForm) Validate(req *http.Request, errs binding.Errors) bindi
 	return middleware.Validate(errs, ctx.Data, f, ctx.Locale)
 }
 
+// scpRegex matches the SCP-like addresses used by Git to access repositories over SSH.
+var scpRegex = regexp.MustCompile(`^([a-zA-Z0-9_]+)@([a-zA-Z0-9._-]+):(.*)$`)
+
 // ParseRemoteAddr checks if given remote address is valid,
 // and returns composed URL with needed username and password.
 func ParseRemoteAddr(remoteAddr, authUsername, authPassword string) (string, error) {
@@ -103,7 +108,15 @@ func ParseRemoteAddr(remoteAddr, authUsername, authPassword string) (string, err
 		if len(authUsername)+len(authPassword) > 0 {
 			u.User = url.UserPassword(authUsername, authPassword)
 		}
-		remoteAddr = u.String()
+		return u.String(), nil
+	}
+
+	// Detect SCP-like remote addresses and return host.
+	if m := scpRegex.FindStringSubmatch(remoteAddr); m != nil {
+		// Match SCP-like syntax and convert it to a URL.
+		// Eg, "git@forgejo.org:user/repo" becomes
+		// "ssh://git@forgejo.org/user/repo".
+		return fmt.Sprintf("ssh://%s@%s/%s", url.User(m[1]), m[2], m[3]), nil
 	}
 
 	return remoteAddr, nil
@@ -127,6 +140,7 @@ type RepoSettingForm struct {
 	PushMirrorPassword     string
 	PushMirrorSyncOnCommit bool
 	PushMirrorInterval     string
+	PushMirrorUseSSH       bool
 	Private                bool
 	Template               bool
 	EnablePrune            bool

services/migrations/migrate.go

@@ -71,7 +71,7 @@ func IsMigrateURLAllowed(remoteURL string, doer *user_model.User) error {
 		return &models.ErrInvalidCloneAddr{Host: u.Host, IsURLError: true}
 	}
 
-	if u.Opaque != "" || u.Scheme != "" && u.Scheme != "http" && u.Scheme != "https" && u.Scheme != "git" {
+	if u.Opaque != "" || u.Scheme != "" && u.Scheme != "http" && u.Scheme != "https" && u.Scheme != "git" && u.Scheme != "ssh" {
 		return &models.ErrInvalidCloneAddr{Host: u.Host, IsProtocolInvalid: true, IsPermissionDenied: true, IsURLError: true}
 	}
 

services/mirror/mirror_push.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 	"regexp"
 	"strings"
 	"time"
@@ -169,11 +170,43 @@ func runPushSync(ctx context.Context, m *repo_model.PushMirror) error {
 
 		log.Trace("Pushing %s mirror[%d] remote %s", path, m.ID, m.RemoteName)
 
+		// OpenSSH isn't very intuitive when you want to specify a specific keypair.
+		// Therefore, we need to create a temporary file that stores the private key, so that OpenSSH can use it.
+		// We delete the the temporary file afterwards.
+		privateKeyPath := ""
+		if m.PublicKey != "" {
+			f, err := os.CreateTemp(os.TempDir(), m.RemoteName)
+			if err != nil {
+				log.Error("os.CreateTemp: %v", err)
+				return errors.New("unexpected error")
+			}
+
+			defer func() {
+				f.Close()
+				if err := os.Remove(f.Name()); err != nil {
+					log.Error("os.Remove: %v", err)
+				}
+			}()
+
+			privateKey, err := m.Privatekey()
+			if err != nil {
+				log.Error("Privatekey: %v", err)
+				return errors.New("unexpected error")
+			}
+
+			if _, err := f.Write(privateKey); err != nil {
+				log.Error("f.Write: %v", err)
+				return errors.New("unexpected error")
+			}
+
+			privateKeyPath = f.Name()
+		}
 		if err := git.Push(ctx, path, git.PushOptions{
 			Remote:         m.RemoteName,
 			Force:          true,
 			Mirror:         true,
 			Timeout:        timeout,
+			PrivateKeyPath: privateKeyPath,
 		}); err != nil {
 			log.Error("Error pushing %s mirror[%d] remote %s: %v", path, m.ID, m.RemoteName, err)
 

templates/repo/settings/options.tmpl

@@ -136,6 +136,7 @@
 								<th class="tw-w-2/5">{{ctx.Locale.Tr "repo.settings.mirror_settings.mirrored_repository"}}</th>
 								<th>{{ctx.Locale.Tr "repo.settings.mirror_settings.direction"}}</th>
 								<th>{{ctx.Locale.Tr "repo.settings.mirror_settings.last_update"}}</th>
+								<th>{{ctx.Locale.Tr "repo.mirror_public_key"}}</th>
 								<th></th>
 							</tr>
 						</thead>
@@ -233,6 +234,7 @@
 								<th class="tw-w-2/5">{{ctx.Locale.Tr "repo.settings.mirror_settings.pushed_repository"}}</th>
 								<th>{{ctx.Locale.Tr "repo.settings.mirror_settings.direction"}}</th>
 								<th>{{ctx.Locale.Tr "repo.settings.mirror_settings.last_update"}}</th>
+								<th>{{ctx.Locale.Tr "repo.mirror_public_key"}}</th>
 								<th></th>
 							</tr>
 						</thead>
@@ -242,7 +244,8 @@
 								<td class="tw-break-anywhere">{{.RemoteAddress}}</td>
 								<td>{{ctx.Locale.Tr "repo.settings.mirror_settings.direction.push"}}</td>
 								<td>{{if .LastUpdateUnix}}{{DateTime "full" .LastUpdateUnix}}{{else}}{{ctx.Locale.Tr "never"}}{{end}} {{if .LastError}}<div class="ui red label" data-tooltip-content="{{.LastError}}">{{ctx.Locale.Tr "error"}}</div>{{end}}</td>
-								<td class="right aligned">
+								<td>{{if not (eq (len .GetPublicKey) 0)}}<a data-clipboard-text="{{.GetPublicKey}}">{{ctx.Locale.Tr "repo.settings.mirror_settings.push_mirror.copy_public_key"}}</a>{{else}}{{ctx.Locale.Tr "repo.settings.mirror_settings.push_mirror.none"}}{{end}}</td>
+								<td class="right aligned df">
 									<button
 										class="ui tiny button show-modal"
 										data-modal="#push-mirror-edit-modal"
@@ -274,7 +277,7 @@
 							{{end}}
 							{{if (not .DisableNewPushMirrors)}}
 								<tr>
-									<td colspan="4">
+									<td colspan="5">
 										<form class="ui form" method="post">
 											{{template "base/disable_form_autofill"}}
 											{{.CsrfTokenHtml}}
@@ -297,6 +300,13 @@
 														<label for="push_mirror_password">{{ctx.Locale.Tr "password"}}</label>
 														<input id="push_mirror_password" name="push_mirror_password" type="password" value="{{.push_mirror_password}}" autocomplete="off">
 													</div>
+													<div class="inline field {{if .Err_PushMirrorUseSSH}}error{{end}}">
+														<div class="ui checkbox df ac">
+															<input id="push_mirror_use_ssh" name="push_mirror_use_ssh" type="checkbox" {{if .push_mirror_use_ssh}}checked{{end}}>
+															<label for="push_mirror_use_ssh" class="inline">{{ctx.Locale.Tr "repo.mirror_use_ssh.text"}}</label>
+															<span class="help tw-block">{{ctx.Locale.Tr "repo.mirror_use_ssh.helper"}}
+														</div>
+													</div>
 												</div>
 											</details>
 											<div class="field">

templates/swagger/v1_json.tmpl

@@ -21529,6 +21529,10 @@
         "sync_on_commit": {
           "type": "boolean",
           "x-go-name": "SyncOnCommit"
+        },
+        "use_ssh": {
+          "type": "boolean",
+          "x-go-name": "UseSSH"
         }
       },
       "x-go-package": "code.gitea.io/gitea/modules/structs"
@@ -25325,6 +25329,10 @@
           "format": "date-time",
           "x-go-name": "LastUpdateUnix"
         },
+        "public_key": {
+          "type": "string",
+          "x-go-name": "PublicKey"
+        },
         "remote_address": {
           "type": "string",
           "x-go-name": "RemoteAddress"

tests/integration/api_push_mirror_test.go

@@ -7,21 +7,30 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net"
 	"net/http"
 	"net/url"
+	"os"
+	"path/filepath"
+	"strconv"
 	"testing"
+	"time"
 
+	asymkey_model "code.gitea.io/gitea/models/asymkey"
 	auth_model "code.gitea.io/gitea/models/auth"
 	"code.gitea.io/gitea/models/db"
 	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unit"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/optional"
 	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/test"
 	"code.gitea.io/gitea/services/migrations"
 	mirror_service "code.gitea.io/gitea/services/mirror"
 	repo_service "code.gitea.io/gitea/services/repository"
+	"code.gitea.io/gitea/tests"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -130,3 +139,130 @@ func testAPIPushMirror(t *testing.T, u *url.URL) {
 		})
 	}
 }
+
+func TestAPIPushMirrorSSH(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, _ *url.URL) {
+		defer test.MockVariableValue(&setting.Migrations.AllowLocalNetworks, true)()
+		defer test.MockVariableValue(&setting.Mirror.Enabled, true)()
+		defer test.MockVariableValue(&setting.SSH.RootPath, t.TempDir())()
+		require.NoError(t, migrations.Init())
+
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+		srcRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2})
+		assert.False(t, srcRepo.HasWiki())
+		session := loginUser(t, user.Name)
+		token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
+		pushToRepo, _, f := CreateDeclarativeRepoWithOptions(t, user, DeclarativeRepoOptions{
+			Name:         optional.Some("push-mirror-test"),
+			AutoInit:     optional.Some(false),
+			EnabledUnits: optional.Some([]unit.Type{unit.TypeCode}),
+		})
+		defer f()
+
+		sshURL := fmt.Sprintf("ssh://%s@%s/%s.git", setting.SSH.User, net.JoinHostPort(setting.SSH.ListenHost, strconv.Itoa(setting.SSH.ListenPort)), pushToRepo.FullName())
+
+		t.Run("Mutual exclusive", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			req := NewRequestWithJSON(t, "POST", fmt.Sprintf("/api/v1/repos/%s/push_mirrors", srcRepo.FullName()), &api.CreatePushMirrorOption{
+				RemoteAddress:  sshURL,
+				Interval:       "8h",
+				UseSSH:         true,
+				RemoteUsername: "user",
+				RemotePassword: "password",
+			}).AddTokenAuth(token)
+			resp := MakeRequest(t, req, http.StatusBadRequest)
+
+			var apiError api.APIError
+			DecodeJSON(t, resp, &apiError)
+			assert.EqualValues(t, "'use_ssh' is mutually exclusive with 'remote_username' and 'remote_passoword'", apiError.Message)
+		})
+
+		t.Run("Normal", func(t *testing.T) {
+			var pushMirror *repo_model.PushMirror
+			t.Run("Adding", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequestWithJSON(t, "POST", fmt.Sprintf("/api/v1/repos/%s/push_mirrors", srcRepo.FullName()), &api.CreatePushMirrorOption{
+					RemoteAddress: sshURL,
+					Interval:      "8h",
+					UseSSH:        true,
+				}).AddTokenAuth(token)
+				MakeRequest(t, req, http.StatusOK)
+
+				pushMirror = unittest.AssertExistsAndLoadBean(t, &repo_model.PushMirror{RepoID: srcRepo.ID})
+				assert.NotEmpty(t, pushMirror.PrivateKey)
+				assert.NotEmpty(t, pushMirror.PublicKey)
+			})
+
+			publickey := pushMirror.GetPublicKey()
+			t.Run("Publickey", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequest(t, "GET", fmt.Sprintf("/api/v1/repos/%s/push_mirrors", srcRepo.FullName())).AddTokenAuth(token)
+				resp := MakeRequest(t, req, http.StatusOK)
+
+				var pushMirrors []*api.PushMirror
+				DecodeJSON(t, resp, &pushMirrors)
+				assert.Len(t, pushMirrors, 1)
+				assert.EqualValues(t, publickey, pushMirrors[0].PublicKey)
+			})
+
+			t.Run("Add deploy key", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequestWithJSON(t, "POST", fmt.Sprintf("/api/v1/repos/%s/keys", pushToRepo.FullName()), &api.CreateKeyOption{
+					Title:    "push mirror key",
+					Key:      publickey,
+					ReadOnly: false,
+				}).AddTokenAuth(token)
+				MakeRequest(t, req, http.StatusCreated)
+
+				unittest.AssertExistsAndLoadBean(t, &asymkey_model.DeployKey{Name: "push mirror key", RepoID: pushToRepo.ID})
+			})
+
+			t.Run("Synchronize", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequest(t, "POST", fmt.Sprintf("/api/v1/repos/%s/push_mirrors-sync", srcRepo.FullName())).AddTokenAuth(token)
+				MakeRequest(t, req, http.StatusOK)
+			})
+
+			t.Run("Check mirrored content", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+				sha := "1032bbf17fbc0d9c95bb5418dabe8f8c99278700"
+
+				req := NewRequest(t, "GET", fmt.Sprintf("/api/v1/repos/%s/commits?limit=1", srcRepo.FullName())).AddTokenAuth(token)
+				resp := MakeRequest(t, req, http.StatusOK)
+
+				var commitList []*api.Commit
+				DecodeJSON(t, resp, &commitList)
+
+				assert.Len(t, commitList, 1)
+				assert.EqualValues(t, sha, commitList[0].SHA)
+
+				assert.Eventually(t, func() bool {
+					req := NewRequest(t, "GET", fmt.Sprintf("/api/v1/repos/%s/commits?limit=1", srcRepo.FullName())).AddTokenAuth(token)
+					resp := MakeRequest(t, req, http.StatusOK)
+
+					var commitList []*api.Commit
+					DecodeJSON(t, resp, &commitList)
+
+					return len(commitList) != 0 && commitList[0].SHA == sha
+				}, time.Second*30, time.Second)
+			})
+
+			t.Run("Check known host keys", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				knownHosts, err := os.ReadFile(filepath.Join(setting.SSH.RootPath, "known_hosts"))
+				require.NoError(t, err)
+
+				publicKey, err := os.ReadFile(setting.SSH.ServerHostKeys[0] + ".pub")
+				require.NoError(t, err)
+
+				assert.Contains(t, string(knownHosts), string(publicKey))
+			})
+		})
+	})
+}

tests/integration/mirror_push_test.go

@@ -1,4 +1,5 @@
 // Copyright 2021 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package integration
@@ -6,18 +7,26 @@ package integration
 import (
 	"context"
 	"fmt"
+	"net"
 	"net/http"
 	"net/url"
+	"os"
+	"path/filepath"
 	"strconv"
 	"testing"
+	"time"
 
+	asymkey_model "code.gitea.io/gitea/models/asymkey"
 	"code.gitea.io/gitea/models/db"
 	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unit"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/optional"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
 	gitea_context "code.gitea.io/gitea/services/context"
 	doctor "code.gitea.io/gitea/services/doctor"
 	"code.gitea.io/gitea/services/migrations"
@@ -35,8 +44,8 @@ func TestMirrorPush(t *testing.T) {
 
 func testMirrorPush(t *testing.T, u *url.URL) {
 	defer tests.PrepareTestEnv(t)()
+	defer test.MockVariableValue(&setting.Migrations.AllowLocalNetworks, true)()
 
-	setting.Migrations.AllowLocalNetworks = true
 	require.NoError(t, migrations.Init())
 
 	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
@@ -146,3 +155,135 @@ func doRemovePushMirror(ctx APITestContext, address, username, password string,
 		assert.Contains(t, flashCookie.Value, "success")
 	}
 }
+
+func TestSSHPushMirror(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, _ *url.URL) {
+		defer test.MockVariableValue(&setting.Migrations.AllowLocalNetworks, true)()
+		defer test.MockVariableValue(&setting.Mirror.Enabled, true)()
+		defer test.MockVariableValue(&setting.SSH.RootPath, t.TempDir())()
+		require.NoError(t, migrations.Init())
+
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+		srcRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2})
+		assert.False(t, srcRepo.HasWiki())
+		sess := loginUser(t, user.Name)
+		pushToRepo, _, f := CreateDeclarativeRepoWithOptions(t, user, DeclarativeRepoOptions{
+			Name:         optional.Some("push-mirror-test"),
+			AutoInit:     optional.Some(false),
+			EnabledUnits: optional.Some([]unit.Type{unit.TypeCode}),
+		})
+		defer f()
+
+		sshURL := fmt.Sprintf("ssh://%s@%s/%s.git", setting.SSH.User, net.JoinHostPort(setting.SSH.ListenHost, strconv.Itoa(setting.SSH.ListenPort)), pushToRepo.FullName())
+		t.Run("Mutual exclusive", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			req := NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/settings", srcRepo.FullName()), map[string]string{
+				"_csrf":                GetCSRF(t, sess, fmt.Sprintf("/%s/settings", srcRepo.FullName())),
+				"action":               "push-mirror-add",
+				"push_mirror_address":  sshURL,
+				"push_mirror_username": "username",
+				"push_mirror_password": "password",
+				"push_mirror_use_ssh":  "true",
+				"push_mirror_interval": "0",
+			})
+			resp := sess.MakeRequest(t, req, http.StatusOK)
+			htmlDoc := NewHTMLParser(t, resp.Body)
+
+			errMsg := htmlDoc.Find(".ui.negative.message").Text()
+			assert.Contains(t, errMsg, "Cannot use public key and password based authentication in combination.")
+		})
+
+		t.Run("Normal", func(t *testing.T) {
+			var pushMirror *repo_model.PushMirror
+			t.Run("Adding", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/settings", srcRepo.FullName()), map[string]string{
+					"_csrf":                GetCSRF(t, sess, fmt.Sprintf("/%s/settings", srcRepo.FullName())),
+					"action":               "push-mirror-add",
+					"push_mirror_address":  sshURL,
+					"push_mirror_use_ssh":  "true",
+					"push_mirror_interval": "0",
+				})
+				sess.MakeRequest(t, req, http.StatusSeeOther)
+
+				flashCookie := sess.GetCookie(gitea_context.CookieNameFlash)
+				assert.NotNil(t, flashCookie)
+				assert.Contains(t, flashCookie.Value, "success")
+
+				pushMirror = unittest.AssertExistsAndLoadBean(t, &repo_model.PushMirror{RepoID: srcRepo.ID})
+				assert.NotEmpty(t, pushMirror.PrivateKey)
+				assert.NotEmpty(t, pushMirror.PublicKey)
+			})
+
+			publickey := ""
+			t.Run("Publickey", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequest(t, "GET", fmt.Sprintf("/%s/settings", srcRepo.FullName()))
+				resp := sess.MakeRequest(t, req, http.StatusOK)
+				htmlDoc := NewHTMLParser(t, resp.Body)
+
+				publickey = htmlDoc.Find(".ui.table td a[data-clipboard-text]").AttrOr("data-clipboard-text", "")
+				assert.EqualValues(t, publickey, pushMirror.GetPublicKey())
+			})
+
+			t.Run("Add deploy key", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/settings/keys", pushToRepo.FullName()), map[string]string{
+					"_csrf":       GetCSRF(t, sess, fmt.Sprintf("/%s/settings/keys", pushToRepo.FullName())),
+					"title":       "push mirror key",
+					"content":     publickey,
+					"is_writable": "true",
+				})
+				sess.MakeRequest(t, req, http.StatusSeeOther)
+
+				unittest.AssertExistsAndLoadBean(t, &asymkey_model.DeployKey{Name: "push mirror key", RepoID: pushToRepo.ID})
+			})
+
+			t.Run("Synchronize", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				req := NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/settings", srcRepo.FullName()), map[string]string{
+					"_csrf":          GetCSRF(t, sess, fmt.Sprintf("/%s/settings", srcRepo.FullName())),
+					"action":         "push-mirror-sync",
+					"push_mirror_id": strconv.FormatInt(pushMirror.ID, 10),
+				})
+				sess.MakeRequest(t, req, http.StatusSeeOther)
+			})
+
+			t.Run("Check mirrored content", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+				shortSHA := "1032bbf17f"
+
+				req := NewRequest(t, "GET", fmt.Sprintf("/%s", srcRepo.FullName()))
+				resp := sess.MakeRequest(t, req, http.StatusOK)
+				htmlDoc := NewHTMLParser(t, resp.Body)
+
+				assert.Contains(t, htmlDoc.Find(".shortsha").Text(), shortSHA)
+
+				assert.Eventually(t, func() bool {
+					req = NewRequest(t, "GET", fmt.Sprintf("/%s", pushToRepo.FullName()))
+					resp = sess.MakeRequest(t, req, http.StatusOK)
+					htmlDoc = NewHTMLParser(t, resp.Body)
+
+					return htmlDoc.Find(".shortsha").Text() == shortSHA
+				}, time.Second*30, time.Second)
+			})
+
+			t.Run("Check known host keys", func(t *testing.T) {
+				defer tests.PrintCurrentTest(t)()
+
+				knownHosts, err := os.ReadFile(filepath.Join(setting.SSH.RootPath, "known_hosts"))
+				require.NoError(t, err)
+
+				publicKey, err := os.ReadFile(setting.SSH.ServerHostKeys[0] + ".pub")
+				require.NoError(t, err)
+
+				assert.Contains(t, string(knownHosts), string(publicKey))
+			})
+		})
+	})
+}