mirror of https://github.com/kubernetes/kops.git
255 lines
7.2 KiB
Go
255 lines
7.2 KiB
Go
/*
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Copyright 2020 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package awsup
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import (
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"bytes"
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"context"
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"crypto/sha256"
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"encoding/base64"
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"encoding/json"
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"encoding/xml"
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"fmt"
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"io"
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"io/ioutil"
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"net"
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"net/http"
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"strconv"
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"strings"
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"time"
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"github.com/aws/aws-sdk-go/aws"
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"github.com/aws/aws-sdk-go/aws/endpoints"
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"github.com/aws/aws-sdk-go/aws/session"
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"github.com/aws/aws-sdk-go/service/ec2"
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"github.com/aws/aws-sdk-go/service/sts"
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"k8s.io/kops/pkg/bootstrap"
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nodeidentityaws "k8s.io/kops/pkg/nodeidentity/aws"
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)
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type AWSVerifierOptions struct {
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// NodesRoles are the IAM roles that worker nodes are permitted to have.
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NodesRoles []string `json:"nodesRoles"`
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// Region is the AWS region of the cluster.
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Region string
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}
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type awsVerifier struct {
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accountId string
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partition string
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opt AWSVerifierOptions
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ec2 *ec2.EC2
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sts *sts.STS
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client http.Client
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}
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var _ bootstrap.Verifier = &awsVerifier{}
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func NewAWSVerifier(opt *AWSVerifierOptions) (bootstrap.Verifier, error) {
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config := aws.NewConfig().
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WithCredentialsChainVerboseErrors(true).
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WithRegion(opt.Region).
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WithSTSRegionalEndpoint(endpoints.RegionalSTSEndpoint)
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sess, err := session.NewSession(config)
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if err != nil {
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return nil, err
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}
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stsClient := sts.New(sess, config)
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identity, err := stsClient.GetCallerIdentity(&sts.GetCallerIdentityInput{})
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if err != nil {
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return nil, err
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}
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partition := strings.Split(aws.StringValue(identity.Arn), ":")[1]
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ec2Client := ec2.New(sess, config)
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return &awsVerifier{
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accountId: aws.StringValue(identity.Account),
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partition: partition,
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opt: *opt,
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ec2: ec2Client,
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sts: stsClient,
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client: http.Client{
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Transport: &http.Transport{
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Proxy: http.ProxyFromEnvironment,
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DialContext: (&net.Dialer{
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Timeout: 30 * time.Second,
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}).DialContext,
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ForceAttemptHTTP2: true,
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DisableKeepAlives: true,
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MaxIdleConnsPerHost: -1,
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TLSHandshakeTimeout: 10 * time.Second,
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ExpectContinueTimeout: 1 * time.Second,
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},
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CheckRedirect: func(req *http.Request, via []*http.Request) error {
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return http.ErrUseLastResponse
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},
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},
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}, nil
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}
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type GetCallerIdentityResponse struct {
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XMLName xml.Name `xml:"GetCallerIdentityResponse"`
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GetCallerIdentityResult []GetCallerIdentityResult `xml:"GetCallerIdentityResult"`
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ResponseMetadata []ResponseMetadata `xml:"ResponseMetadata"`
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}
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type GetCallerIdentityResult struct {
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Arn string `xml:"Arn"`
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UserId string `xml:"UserId"`
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Account string `xml:"Account"`
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}
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type ResponseMetadata struct {
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RequestId string `xml:"RequestId"`
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}
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func (a awsVerifier) VerifyToken(ctx context.Context, token string, body []byte) (*bootstrap.VerifyResult, error) {
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if !strings.HasPrefix(token, AWSAuthenticationTokenPrefix) {
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return nil, fmt.Errorf("incorrect authorization type")
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}
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token = strings.TrimPrefix(token, AWSAuthenticationTokenPrefix)
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// We rely on the client and server using the same version of the same STS library.
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stsRequest, _ := a.sts.GetCallerIdentityRequest(nil)
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err := stsRequest.Sign()
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if err != nil {
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return nil, fmt.Errorf("creating identity request: %v", err)
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}
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stsRequest.HTTPRequest.Header = nil
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tokenBytes, err := base64.StdEncoding.DecodeString(token)
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if err != nil {
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return nil, fmt.Errorf("decoding authorization token: %v", err)
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}
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err = json.Unmarshal(tokenBytes, &stsRequest.HTTPRequest.Header)
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if err != nil {
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return nil, fmt.Errorf("unmarshalling authorization token: %v", err)
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}
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// Verify the token has signed the body content.
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sha := sha256.Sum256(body)
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if stsRequest.HTTPRequest.Header.Get("X-Kops-Request-SHA") != base64.RawStdEncoding.EncodeToString(sha[:]) {
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return nil, fmt.Errorf("incorrect SHA")
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}
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requestBytes, _ := ioutil.ReadAll(stsRequest.Body)
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_, _ = stsRequest.Body.Seek(0, io.SeekStart)
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if stsRequest.HTTPRequest.Header.Get("Content-Length") != strconv.Itoa(len(requestBytes)) {
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return nil, fmt.Errorf("incorrect content-length")
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}
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response, err := a.client.Do(stsRequest.HTTPRequest)
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if err != nil {
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return nil, fmt.Errorf("sending STS request: %v", err)
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}
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if response != nil {
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defer response.Body.Close()
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}
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responseBody, err := ioutil.ReadAll(response.Body)
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if err != nil {
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return nil, fmt.Errorf("reading STS response: %v", err)
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}
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if response.StatusCode != 200 {
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return nil, fmt.Errorf("received status code %d from STS: %s", response.StatusCode, string(responseBody))
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}
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callerIdentity := GetCallerIdentityResponse{}
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err = xml.NewDecoder(bytes.NewReader(responseBody)).Decode(&callerIdentity)
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if err != nil {
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return nil, fmt.Errorf("decoding STS response: %v", err)
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}
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if callerIdentity.GetCallerIdentityResult[0].Account != a.accountId {
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return nil, fmt.Errorf("incorrect account %s", callerIdentity.GetCallerIdentityResult[0].Account)
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}
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arn := callerIdentity.GetCallerIdentityResult[0].Arn
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parts := strings.Split(arn, ":")
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if len(parts) != 6 {
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return nil, fmt.Errorf("arn %q contains unexpected number of colons", arn)
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}
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if parts[0] != "arn" {
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return nil, fmt.Errorf("arn %q doesn't start with \"arn:\"", arn)
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}
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if parts[1] != a.partition {
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return nil, fmt.Errorf("arn %q not in partion %q", arn, a.partition)
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}
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if parts[2] != "iam" && parts[2] != "sts" {
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return nil, fmt.Errorf("arn %q has unrecognized service", arn)
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}
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// parts[3] is region
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// parts[4] is account
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resource := strings.Split(parts[5], "/")
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if resource[0] != "assumed-role" {
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return nil, fmt.Errorf("arn %q has unrecognized type", arn)
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}
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if len(resource) < 3 {
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return nil, fmt.Errorf("arn %q contains too few slashes", arn)
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}
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found := false
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for _, role := range a.opt.NodesRoles {
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if resource[1] == role {
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found = true
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break
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}
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}
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if !found {
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return nil, fmt.Errorf("arn %q does not contain acceptable node role", arn)
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}
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instanceID := resource[2]
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instances, err := a.ec2.DescribeInstances(&ec2.DescribeInstancesInput{
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InstanceIds: aws.StringSlice([]string{instanceID}),
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})
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if err != nil {
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return nil, fmt.Errorf("describing instance for arn %q", arn)
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}
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if len(instances.Reservations) <= 0 || len(instances.Reservations[0].Instances) <= 0 {
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return nil, fmt.Errorf("missing instance id: %s", instanceID)
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}
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if len(instances.Reservations[0].Instances) > 1 {
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return nil, fmt.Errorf("found multiple instances with instance id: %s", instanceID)
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}
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instance := instances.Reservations[0].Instances[0]
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addrs, err := GetInstanceCertificateNames(instances)
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if err != nil {
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return nil, err
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}
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result := &bootstrap.VerifyResult{
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NodeName: addrs[0],
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CertificateNames: addrs,
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}
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for _, tag := range instance.Tags {
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tagKey := aws.StringValue(tag.Key)
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if tagKey == nodeidentityaws.CloudTagInstanceGroupName {
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result.InstanceGroupName = aws.StringValue(tag.Value)
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}
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}
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return result, nil
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}
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