google.golang.org/grpc@v1.74.2/credentials/local/local.go (about)

     1  /*
     2   *
     3   * Copyright 2020 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  // Package local implements local transport credentials.
    20  // Local credentials reports the security level based on the type
    21  // of connection. If the connection is local TCP, NoSecurity will be
    22  // reported, and if the connection is UDS, PrivacyAndIntegrity will be
    23  // reported. If local credentials is not used in local connections
    24  // (local TCP or UDS), it will fail.
    25  //
    26  // # Experimental
    27  //
    28  // Notice: This package is EXPERIMENTAL and may be changed or removed in a
    29  // later release.
    30  package local
    31  
    32  import (
    33  	"context"
    34  	"fmt"
    35  	"net"
    36  	"strings"
    37  
    38  	"google.golang.org/grpc/credentials"
    39  )
    40  
    41  // info contains the auth information for a local connection.
    42  // It implements the AuthInfo interface.
    43  type info struct {
    44  	credentials.CommonAuthInfo
    45  }
    46  
    47  // AuthType returns the type of info as a string.
    48  func (info) AuthType() string {
    49  	return "local"
    50  }
    51  
    52  // ValidateAuthority allows any value to be overridden for the :authority
    53  // header.
    54  func (info) ValidateAuthority(string) error {
    55  	return nil
    56  }
    57  
    58  // localTC is the credentials required to establish a local connection.
    59  type localTC struct {
    60  	info credentials.ProtocolInfo
    61  }
    62  
    63  func (c *localTC) Info() credentials.ProtocolInfo {
    64  	return c.info
    65  }
    66  
    67  // getSecurityLevel returns the security level for a local connection.
    68  // It returns an error if a connection is not local.
    69  func getSecurityLevel(network, addr string) (credentials.SecurityLevel, error) {
    70  	switch {
    71  	// Local TCP connection
    72  	case strings.HasPrefix(addr, "127."), strings.HasPrefix(addr, "[::1]:"):
    73  		return credentials.NoSecurity, nil
    74  	// Windows named pipe connection
    75  	case network == "pipe" && strings.HasPrefix(addr, `\\.\pipe\`):
    76  		return credentials.NoSecurity, nil
    77  	// UDS connection
    78  	case network == "unix":
    79  		return credentials.PrivacyAndIntegrity, nil
    80  	// Not a local connection and should fail
    81  	default:
    82  		return credentials.InvalidSecurityLevel, fmt.Errorf("local credentials rejected connection to non-local address %q", addr)
    83  	}
    84  }
    85  
    86  func (*localTC) ClientHandshake(_ context.Context, _ string, conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
    87  	secLevel, err := getSecurityLevel(conn.RemoteAddr().Network(), conn.RemoteAddr().String())
    88  	if err != nil {
    89  		return nil, nil, err
    90  	}
    91  	return conn, info{credentials.CommonAuthInfo{SecurityLevel: secLevel}}, nil
    92  }
    93  
    94  func (*localTC) ServerHandshake(conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
    95  	secLevel, err := getSecurityLevel(conn.RemoteAddr().Network(), conn.RemoteAddr().String())
    96  	if err != nil {
    97  		return nil, nil, err
    98  	}
    99  	return conn, info{credentials.CommonAuthInfo{SecurityLevel: secLevel}}, nil
   100  }
   101  
   102  // NewCredentials returns a local credential implementing credentials.TransportCredentials.
   103  func NewCredentials() credentials.TransportCredentials {
   104  	return &localTC{
   105  		info: credentials.ProtocolInfo{
   106  			SecurityProtocol: "local",
   107  		},
   108  	}
   109  }
   110  
   111  // Clone makes a copy of Local credentials.
   112  func (c *localTC) Clone() credentials.TransportCredentials {
   113  	return &localTC{info: c.info}
   114  }
   115  
   116  // OverrideServerName overrides the server name used to verify the hostname on the returned certificates from the server.
   117  // Since this feature is specific to TLS (SNI + hostname verification check), it does not take any effect for local credentials.
   118  func (c *localTC) OverrideServerName(serverNameOverride string) error {
   119  	c.info.ServerName = serverNameOverride
   120  	return nil
   121  }