diff --git a/authority/provisioner/aws.go b/authority/provisioner/aws.go index f3b539d6..9da6a9f3 100644 --- a/authority/provisioner/aws.go +++ b/authority/provisioner/aws.go @@ -147,6 +147,7 @@ type AWS struct { Accounts []string `json:"accounts"` DisableCustomSANs bool `json:"disableCustomSANs"` DisableTrustOnFirstUse bool `json:"disableTrustOnFirstUse"` + IMDSVersions []string `json:"imdsVersions"` InstanceAge Duration `json:"instanceAge,omitempty"` Claims *Claims `json:"claims,omitempty"` claimer *Claimer @@ -200,14 +201,14 @@ func (p *AWS) GetIdentityToken(subject, caURL string) (string, error) { var idoc awsInstanceIdentityDocument doc, err := p.readURL(p.config.identityURL) if err != nil { - return "", errors.Wrap(err, "error retrieving identity document, are you in an AWS VM with IMDSv2 enabled?") + return "", errors.Wrap(err, "error retrieving identity document, are you in an AWS VM using the proper IMDS version?") } if err := json.Unmarshal(doc, &idoc); err != nil { return "", errors.Wrap(err, "error unmarshaling identity document") } sig, err := p.readURL(p.config.signatureURL) if err != nil { - return "", errors.Wrap(err, "error retrieving identity document signature, are you in an AWS VM with IMDSv2 enabled?") + return "", errors.Wrap(err, "error retrieving identity document signature, are you in an AWS VM using the proper IMDS version?") } signature, err := base64.StdEncoding.DecodeString(string(sig)) if err != nil { @@ -349,43 +350,87 @@ func (p *AWS) checkSignature(signed, signature []byte) error { // using pkg/errors to avoid verbose errors, the caller should use it and write // the appropriate error. func (p *AWS) readURL(url string) ([]byte, error) { - client := &http.Client{} + var resp *http.Response + var err error - // get authorization token + for _, v := range p.IMDSVersions { + switch v { + case "v1": + resp, err = p.readURLv1(url) + if err == nil && resp.StatusCode < 400 { + return p.readResponseBody(resp) + } + case "v2": + resp, err = p.readURLv2(url) + if err == nil && resp.StatusCode < 400 { + return p.readResponseBody(resp) + } + default: + return nil, fmt.Errorf("%s: not a supported AWS Instance Metadata Service version", v) + } + } + + // all versions have been exhausted and we haven't returned successfully yet so pass + // the error on to the caller + if err != nil { + return nil, err + } + return nil, fmt.Errorf("Request for metadata returned non-successful status code %d", + resp.StatusCode) +} + +func (p *AWS) readURLv1(url string) (*http.Response, error) { + client := http.Client{} + + req, err := http.NewRequest(http.MethodGet, url, nil) + if err != nil { + return nil, err + } + resp, err := client.Do(req) + if err != nil { + return nil, err + } + return resp, nil +} + +func (p *AWS) readURLv2(url string) (*http.Response, error) { + client := http.Client{} + + // first get the token req, err := http.NewRequest(http.MethodPut, p.config.tokenURL, nil) if err != nil { return nil, err } req.Header.Set(awsMetadataTokenTTLHeader, p.config.tokenTTL) - r, err := client.Do(req) + resp, err := client.Do(req) if err != nil { return nil, err } - defer r.Body.Close() - if r.StatusCode >= 400 { - return nil, fmt.Errorf("HTTP request returned non-successful status code %d", r.StatusCode) + defer resp.Body.Close() + if resp.StatusCode >= 400 { + return nil, fmt.Errorf("Request for API token returned non-successful status code %d", resp.StatusCode) } - b, err := ioutil.ReadAll(r.Body) + token, err := ioutil.ReadAll(resp.Body) if err != nil { return nil, err } - token := string(b) - // now get the data + // now make the request req, err = http.NewRequest(http.MethodGet, url, nil) if err != nil { return nil, err } - req.Header.Set(awsMetadataTokenHeader, token) - r, err = client.Do(req) + req.Header.Set(awsMetadataTokenHeader, string(token)) + resp, err = client.Do(req) if err != nil { return nil, err } - defer r.Body.Close() - if r.StatusCode >= 400 { - return nil, fmt.Errorf("HTTP request returned non-successful status code %d", r.StatusCode) - } - b, err = ioutil.ReadAll(r.Body) + return resp, nil +} + +func (p *AWS) readResponseBody(resp *http.Response) ([]byte, error) { + defer resp.Body.Close() + b, err := ioutil.ReadAll(resp.Body) if err != nil { return nil, err } diff --git a/authority/provisioner/utils_test.go b/authority/provisioner/utils_test.go index 23e8d86d..84283631 100644 --- a/authority/provisioner/utils_test.go +++ b/authority/provisioner/utils_test.go @@ -408,11 +408,12 @@ func generateAWS() (*AWS, error) { return nil, errors.Wrap(err, "error parsing AWS certificate") } return &AWS{ - Type: "AWS", - Name: name, - Accounts: []string{accountID}, - Claims: &globalProvisionerClaims, - claimer: claimer, + Type: "AWS", + Name: name, + Accounts: []string{accountID}, + Claims: &globalProvisionerClaims, + IMDSVersions: []string{"v2", "v1"}, + claimer: claimer, config: &awsConfig{ identityURL: awsIdentityURL, signatureURL: awsSignatureURL,