snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

credentials/local/local.go

@@ -0,0 +1,121 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package local implements local transport credentials.
+// Local credentials reports the security level based on the type
+// of connection. If the connection is local TCP, NoSecurity will be
+// reported, and if the connection is UDS, PrivacyAndIntegrity will be
+// reported. If local credentials is not used in local connections
+// (local TCP or UDS), it will fail.
+//
+// # Experimental
+//
+// Notice: This package is EXPERIMENTAL and may be changed or removed in a
+// later release.
+package local
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"strings"
+
+	"google.golang.org/grpc/credentials"
+)
+
+// info contains the auth information for a local connection.
+// It implements the AuthInfo interface.
+type info struct {
+	credentials.CommonAuthInfo
+}
+
+// AuthType returns the type of info as a string.
+func (info) AuthType() string {
+	return "local"
+}
+
+// ValidateAuthority allows any value to be overridden for the :authority
+// header.
+func (info) ValidateAuthority(string) error {
+	return nil
+}
+
+// localTC is the credentials required to establish a local connection.
+type localTC struct {
+	info credentials.ProtocolInfo
+}
+
+func (c *localTC) Info() credentials.ProtocolInfo {
+	return c.info
+}
+
+// getSecurityLevel returns the security level for a local connection.
+// It returns an error if a connection is not local.
+func getSecurityLevel(network, addr string) (credentials.SecurityLevel, error) {
+	switch {
+	// Local TCP connection
+	case strings.HasPrefix(addr, "127."), strings.HasPrefix(addr, "[::1]:"):
+		return credentials.NoSecurity, nil
+	// Windows named pipe connection
+	case network == "pipe" && strings.HasPrefix(addr, `\\.\pipe\`):
+		return credentials.NoSecurity, nil
+	// UDS connection
+	case network == "unix":
+		return credentials.PrivacyAndIntegrity, nil
+	// Not a local connection and should fail
+	default:
+		return credentials.InvalidSecurityLevel, fmt.Errorf("local credentials rejected connection to non-local address %q", addr)
+	}
+}
+
+func (*localTC) ClientHandshake(_ context.Context, _ string, conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	secLevel, err := getSecurityLevel(conn.RemoteAddr().Network(), conn.RemoteAddr().String())
+	if err != nil {
+		return nil, nil, err
+	}
+	return conn, info{credentials.CommonAuthInfo{SecurityLevel: secLevel}}, nil
+}
+
+func (*localTC) ServerHandshake(conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	secLevel, err := getSecurityLevel(conn.RemoteAddr().Network(), conn.RemoteAddr().String())
+	if err != nil {
+		return nil, nil, err
+	}
+	return conn, info{credentials.CommonAuthInfo{SecurityLevel: secLevel}}, nil
+}
+
+// NewCredentials returns a local credential implementing credentials.TransportCredentials.
+func NewCredentials() credentials.TransportCredentials {
+	return &localTC{
+		info: credentials.ProtocolInfo{
+			SecurityProtocol: "local",
+		},
+	}
+}
+
+// Clone makes a copy of Local credentials.
+func (c *localTC) Clone() credentials.TransportCredentials {
+	return &localTC{info: c.info}
+}
+
+// OverrideServerName overrides the server name used to verify the hostname on the returned certificates from the server.
+// Since this feature is specific to TLS (SNI + hostname verification check), it does not take any effect for local credentials.
+func (c *localTC) OverrideServerName(serverNameOverride string) error {
+	c.info.ServerName = serverNameOverride
+	return nil
+}