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https://github.com/edgelesssys/constellation.git
synced 2025-08-06 05:54:28 -04:00
s3proxy: add allow-multipart flag (#2420)
This flag allows users to control wether multipart uploads are blocked or allowed. At the moment s3proxy doesn't encrypt multipart uploads, so there is a potential for inadvertent data leakage. With this flag the default behavior is changed to a more secure default one: block multipart uploads. The previous behavior can be enabled by setting allow-multipart.
This commit is contained in:
Otto Bittner
GitHub
parent
005e865a13
commit
c603b547db
5 changed files with 253 additions and 151 deletions
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@ -27,7 +27,6 @@ import (
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"encoding/base64"
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"encoding/xml"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"regexp"
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@ -37,7 +36,6 @@ import (
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"github.com/edgelesssys/constellation/v2/internal/logger"
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"github.com/edgelesssys/constellation/v2/s3proxy/internal/kms"
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"github.com/edgelesssys/constellation/v2/s3proxy/internal/s3"
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"go.uber.org/zap"
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)
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const (
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@ -55,11 +53,15 @@ var (
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type Router struct {
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region string
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kek [32]byte
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log *logger.Logger
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// forwardMultipartReqs controls whether we forward the following requests: CreateMultipartUpload, UploadPart, CompleteMultipartUpload, AbortMultipartUpload.
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// s3proxy does not implement those yet.
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// Setting forwardMultipartReqs to true will forward those requests to the S3 API, otherwise we block them (secure defaults).
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forwardMultipartReqs bool
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log *logger.Logger
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}
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// New creates a new Router.
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func New(region, endpoint string, log *logger.Logger) (Router, error) {
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func New(region, endpoint string, forwardMultipartReqs bool, log *logger.Logger) (Router, error) {
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kms := kms.New(log, endpoint)
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// Get the key encryption key that encrypts all DEKs.
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@ -73,7 +75,7 @@ func New(region, endpoint string, log *logger.Logger) (Router, error) {
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return Router{}, fmt.Errorf("converting KEK to byte array: %w", err)
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}
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return Router{region: region, kek: kekArray, log: log}, nil
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return Router{region: region, kek: kekArray, forwardMultipartReqs: forwardMultipartReqs, log: log}, nil
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}
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// Serve implements the routing logic for the s3 proxy.
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@ -103,6 +105,7 @@ func (r Router) Serve(w http.ResponseWriter, req *http.Request) {
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}
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var h http.Handler
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switch {
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// intercept GetObject.
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case matchingPath && req.Method == "GET" && !isUnwantedGetEndpoint(req.URL.Query()):
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@ -110,6 +113,14 @@ func (r Router) Serve(w http.ResponseWriter, req *http.Request) {
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// intercept PutObject.
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case matchingPath && req.Method == "PUT" && !isUnwantedPutEndpoint(req.Header, req.URL.Query()):
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h = handlePutObject(client, key, bucket, r.log)
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case !r.forwardMultipartReqs && matchingPath && isUploadPart(req.Method, req.URL.Query()):
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h = handleUploadPart(r.log)
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case !r.forwardMultipartReqs && matchingPath && isCreateMultipartUpload(req.Method, req.URL.Query()):
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h = handleCreateMultipartUpload(r.log)
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case !r.forwardMultipartReqs && matchingPath && isCompleteMultipartUpload(req.Method, req.URL.Query()):
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h = handleCompleteMultipartUpload(r.log)
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case !r.forwardMultipartReqs && matchingPath && isAbortMultipartUpload(req.Method, req.URL.Query()):
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h = handleAbortMultipartUpload(r.log)
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// Forward all other requests.
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default:
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h = handleForwards(r.log)
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@ -118,6 +129,31 @@ func (r Router) Serve(w http.ResponseWriter, req *http.Request) {
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h.ServeHTTP(w, req)
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}
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func isAbortMultipartUpload(method string, query url.Values) bool {
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_, uploadID := query["uploadId"]
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return method == "DELETE" && uploadID
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}
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func isCompleteMultipartUpload(method string, query url.Values) bool {
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_, multipart := query["uploadId"]
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return method == "POST" && multipart
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}
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func isCreateMultipartUpload(method string, query url.Values) bool {
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_, multipart := query["uploads"]
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return method == "POST" && multipart
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}
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func isUploadPart(method string, query url.Values) bool {
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_, partNumber := query["partNumber"]
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_, uploadID := query["uploadId"]
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return method == "PUT" && partNumber && uploadID
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}
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// ContentSHA256MismatchError is a helper struct to create an XML formatted error message.
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// s3 clients might try to parse error messages, so we need to serve correctly formatted messages.
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type ContentSHA256MismatchError struct {
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@ -138,139 +174,6 @@ func NewContentSHA256MismatchError(clientComputedContentSHA256, s3ComputedConten
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}
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}
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func handleGetObject(client *s3.Client, key string, bucket string, log *logger.Logger) http.HandlerFunc {
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return func(w http.ResponseWriter, req *http.Request) {
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log.With(zap.String("path", req.URL.Path), zap.String("method", req.Method), zap.String("host", req.Host)).Debugf("intercepting")
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if req.Header.Get("Range") != "" {
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log.Errorf("GetObject Range header unsupported")
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http.Error(w, "s3proxy currently does not support Range headers", http.StatusNotImplemented)
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return
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}
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obj := object{
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client: client,
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key: key,
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bucket: bucket,
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query: req.URL.Query(),
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sseCustomerAlgorithm: req.Header.Get("x-amz-server-side-encryption-customer-algorithm"),
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sseCustomerKey: req.Header.Get("x-amz-server-side-encryption-customer-key"),
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sseCustomerKeyMD5: req.Header.Get("x-amz-server-side-encryption-customer-key-MD5"),
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log: log,
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}
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get(obj.get)(w, req)
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}
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}
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func handlePutObject(client *s3.Client, key string, bucket string, log *logger.Logger) http.HandlerFunc {
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return func(w http.ResponseWriter, req *http.Request) {
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log.With(zap.String("path", req.URL.Path), zap.String("method", req.Method), zap.String("host", req.Host)).Debugf("intercepting")
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body, err := io.ReadAll(req.Body)
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if err != nil {
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log.With(zap.Error(err)).Errorf("PutObject")
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http.Error(w, fmt.Sprintf("reading body: %s", err.Error()), http.StatusInternalServerError)
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return
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}
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clientDigest := req.Header.Get("x-amz-content-sha256")
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serverDigest := sha256sum(body)
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// There may be a client that wants to test that incorrect content digests result in API errors.
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// For encrypting the body we have to recalculate the content digest.
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// If the client intentionally sends a mismatching content digest, we would take the client request, rewrap it,
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// calculate the correct digest for the new body and NOT get an error.
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// Thus we have to check incoming requets for matching content digests.
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// UNSIGNED-PAYLOAD can be used to disabled payload signing. In that case we don't check the content digest.
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if clientDigest != "" && clientDigest != "UNSIGNED-PAYLOAD" && clientDigest != serverDigest {
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log.Debugf("PutObject", "error", "x-amz-content-sha256 mismatch")
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// The S3 API responds with an XML formatted error message.
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mismatchErr := NewContentSHA256MismatchError(clientDigest, serverDigest)
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marshalled, err := xml.Marshal(mismatchErr)
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if err != nil {
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log.With(zap.Error(err)).Errorf("PutObject")
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http.Error(w, fmt.Sprintf("marshalling error: %s", err.Error()), http.StatusInternalServerError)
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return
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}
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http.Error(w, string(marshalled), http.StatusBadRequest)
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return
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}
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metadata := getMetadataHeaders(req.Header)
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raw := req.Header.Get("x-amz-object-lock-retain-until-date")
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retentionTime, err := parseRetentionTime(raw)
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if err != nil {
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log.With(zap.String("data", raw), zap.Error(err)).Errorf("parsing lock retention time")
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http.Error(w, fmt.Sprintf("parsing x-amz-object-lock-retain-until-date: %s", err.Error()), http.StatusInternalServerError)
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return
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}
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err = validateContentMD5(req.Header.Get("content-md5"), body)
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if err != nil {
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log.With(zap.Error(err)).Errorf("validating content md5")
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http.Error(w, fmt.Sprintf("validating content md5: %s", err.Error()), http.StatusBadRequest)
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return
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}
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obj := object{
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client: client,
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key: key,
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bucket: bucket,
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data: body,
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query: req.URL.Query(),
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tags: req.Header.Get("x-amz-tagging"),
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contentType: req.Header.Get("Content-Type"),
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metadata: metadata,
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objectLockLegalHoldStatus: req.Header.Get("x-amz-object-lock-legal-hold"),
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objectLockMode: req.Header.Get("x-amz-object-lock-mode"),
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objectLockRetainUntilDate: retentionTime,
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sseCustomerAlgorithm: req.Header.Get("x-amz-server-side-encryption-customer-algorithm"),
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sseCustomerKey: req.Header.Get("x-amz-server-side-encryption-customer-key"),
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sseCustomerKeyMD5: req.Header.Get("x-amz-server-side-encryption-customer-key-MD5"),
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log: log,
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}
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put(obj.put)(w, req)
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}
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}
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func handleForwards(log *logger.Logger) http.HandlerFunc {
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return func(w http.ResponseWriter, req *http.Request) {
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log.With(zap.String("path", req.URL.Path), zap.String("method", req.Method), zap.String("host", req.Host)).Debugf("forwarding")
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newReq := repackage(req)
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httpClient := http.DefaultClient
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resp, err := httpClient.Do(&newReq)
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if err != nil {
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log.With(zap.Error(err)).Errorf("do request")
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http.Error(w, fmt.Sprintf("do request: %s", err.Error()), http.StatusInternalServerError)
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return
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}
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defer resp.Body.Close()
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for key := range resp.Header {
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w.Header().Set(key, resp.Header.Get(key))
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}
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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log.With(zap.Error(err)).Errorf("ReadAll")
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http.Error(w, fmt.Sprintf("reading body: %s", err.Error()), http.StatusInternalServerError)
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return
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}
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w.WriteHeader(resp.StatusCode)
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if body == nil {
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return
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}
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if _, err := w.Write(body); err != nil {
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log.With(zap.Error(err)).Errorf("Write")
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http.Error(w, fmt.Sprintf("writing body: %s", err.Error()), http.StatusInternalServerError)
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return
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}
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}
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}
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// byteSliceToByteArray casts a byte slice to a byte array of length 32.
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// It does a length check to prevent the cast from panic'ing.
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func byteSliceToByteArray(input []byte) ([32]byte, error) {
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