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/*
*
* Copyright 2018 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 alts
import (
"context"
"errors"
"fmt"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"regexp"
"runtime"
"strings"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/peer"
"google.golang.org/grpc/status"
)
const (
linuxProductNameFile = "/sys/class/dmi/id/product_name"
windowsCheckCommand = "powershell.exe"
windowsCheckCommandArgs = "Get-WmiObject -Class Win32_BIOS"
powershellOutputFilter = "Manufacturer"
windowsManufacturerRegex = ":(.*)"
)
type platformError string
func (k platformError) Error() string {
return fmt.Sprintf("%s is not supported", string(k))
}
var (
// The following two variables will be reassigned in tests.
runningOS = runtime.GOOS
manufacturerReader = func() (io.Reader, error) {
switch runningOS {
case "linux":
return os.Open(linuxProductNameFile)
case "windows":
cmd := exec.Command(windowsCheckCommand, windowsCheckCommandArgs)
out, err := cmd.Output()
if err != nil {
return nil, err
}
for _, line := range strings.Split(strings.TrimSuffix(string(out), "\n"), "\n") {
if strings.HasPrefix(line, powershellOutputFilter) {
re := regexp.MustCompile(windowsManufacturerRegex)
name := re.FindString(line)
name = strings.TrimLeft(name, ":")
return strings.NewReader(name), nil
}
}
return nil, errors.New("cannot determine the machine's manufacturer")
default:
return nil, platformError(runningOS)
}
}
vmOnGCP bool
)
// isRunningOnGCP checks whether the local system, without doing a network request is
// running on GCP.
func isRunningOnGCP() bool {
manufacturer, err := readManufacturer()
if os.IsNotExist(err) {
return false
}
if err != nil {
log.Fatalf("failure to read manufacturer information: %v", err)
}
name := string(manufacturer)
switch runningOS {
case "linux":
name = strings.TrimSpace(name)
return name == "Google" || name == "Google Compute Engine"
case "windows":
name = strings.Replace(name, " ", "", -1)
name = strings.Replace(name, "\n", "", -1)
name = strings.Replace(name, "\r", "", -1)
return name == "Google"
default:
log.Fatal(platformError(runningOS))
}
return false
}
func readManufacturer() ([]byte, error) {
reader, err := manufacturerReader()
if err != nil {
return nil, err
}
if reader == nil {
return nil, errors.New("got nil reader")
}
manufacturer, err := ioutil.ReadAll(reader)
if err != nil {
return nil, fmt.Errorf("failed reading %v: %v", linuxProductNameFile, err)
}
return manufacturer, nil
}
// AuthInfoFromContext extracts the alts.AuthInfo object from the given context,
// if it exists. This API should be used by gRPC server RPC handlers to get
// information about the communicating peer. For client-side, use grpc.Peer()
// CallOption.
func AuthInfoFromContext(ctx context.Context) (AuthInfo, error) {
p, ok := peer.FromContext(ctx)
if !ok {
return nil, errors.New("no Peer found in Context")
}
return AuthInfoFromPeer(p)
}
// AuthInfoFromPeer extracts the alts.AuthInfo object from the given peer, if it
// exists. This API should be used by gRPC clients after obtaining a peer object
// using the grpc.Peer() CallOption.
func AuthInfoFromPeer(p *peer.Peer) (AuthInfo, error) {
altsAuthInfo, ok := p.AuthInfo.(AuthInfo)
if !ok {
return nil, errors.New("no alts.AuthInfo found in Peer")
}
return altsAuthInfo, nil
}
// ClientAuthorizationCheck checks whether the client is authorized to access
// the requested resources based on the given expected client service accounts.
// This API should be used by gRPC server RPC handlers. This API should not be
// used by clients.
func ClientAuthorizationCheck(ctx context.Context, expectedServiceAccounts []string) error {
authInfo, err := AuthInfoFromContext(ctx)
if err != nil {
return status.Errorf(codes.PermissionDenied, "The context is not an ALTS-compatible context: %v", err)
}
peer := authInfo.PeerServiceAccount()
for _, sa := range expectedServiceAccounts {
if strings.EqualFold(peer, sa) {
return nil
}
}
return status.Errorf(codes.PermissionDenied, "Client %v is not authorized", peer)
}
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