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minio/cmd/generic-handlers.go

776 lines
23 KiB

/*
* Minio Cloud Storage, (C) 2015, 2016, 2017 Minio, Inc.
*
* 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 cmd
import (
"bufio"
"context"
"fmt"
"net"
"net/http"
"strings"
"time"
"github.com/minio/minio-go/pkg/set"
humanize "github.com/dustin/go-humanize"
"github.com/minio/minio/cmd/logger"
"github.com/minio/minio/pkg/dns"
"github.com/minio/minio/pkg/handlers"
"github.com/minio/minio/pkg/sys"
"github.com/rs/cors"
"golang.org/x/time/rate"
)
// HandlerFunc - useful to chain different middleware http.Handler
type HandlerFunc func(http.Handler) http.Handler
func registerHandlers(h http.Handler, handlerFns ...HandlerFunc) http.Handler {
for _, hFn := range handlerFns {
h = hFn(h)
}
return h
}
// Adds limiting body size middleware
// Maximum allowed form data field values. 64MiB is a guessed practical value
// which is more than enough to accommodate any form data fields and headers.
const requestFormDataSize = 64 * humanize.MiByte
// For any HTTP request, request body should be not more than 16GiB + requestFormDataSize
// where, 16GiB is the maximum allowed object size for object upload.
const requestMaxBodySize = globalMaxObjectSize + requestFormDataSize
type requestSizeLimitHandler struct {
handler http.Handler
maxBodySize int64
}
func setRequestSizeLimitHandler(h http.Handler) http.Handler {
return requestSizeLimitHandler{handler: h, maxBodySize: requestMaxBodySize}
}
func (h requestSizeLimitHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Restricting read data to a given maximum length
r.Body = http.MaxBytesReader(w, r.Body, h.maxBodySize)
h.handler.ServeHTTP(w, r)
}
const (
// Maximum size for http headers - See: https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingMetadata.html
maxHeaderSize = 8 * 1024
// Maximum size for user-defined metadata - See: https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingMetadata.html
maxUserDataSize = 2 * 1024
)
type requestHeaderSizeLimitHandler struct {
http.Handler
}
func setRequestHeaderSizeLimitHandler(h http.Handler) http.Handler {
return requestHeaderSizeLimitHandler{h}
}
// ServeHTTP restricts the size of the http header to 8 KB and the size
// of the user-defined metadata to 2 KB.
func (h requestHeaderSizeLimitHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if isHTTPHeaderSizeTooLarge(r.Header) {
writeErrorResponse(w, ErrMetadataTooLarge, r.URL)
return
}
h.Handler.ServeHTTP(w, r)
}
// isHTTPHeaderSizeTooLarge returns true if the provided
// header is larger than 8 KB or the user-defined metadata
// is larger than 2 KB.
func isHTTPHeaderSizeTooLarge(header http.Header) bool {
var size, usersize int
for key := range header {
length := len(key) + len(header.Get(key))
size += length
for _, prefix := range userMetadataKeyPrefixes {
if strings.HasPrefix(key, prefix) {
usersize += length
break
}
}
if usersize > maxUserDataSize || size > maxHeaderSize {
return true
}
}
return false
}
// ReservedMetadataPrefix is the prefix of a metadata key which
// is reserved and for internal use only.
const ReservedMetadataPrefix = "X-Minio-Internal-"
type reservedMetadataHandler struct {
http.Handler
}
func filterReservedMetadata(h http.Handler) http.Handler {
return reservedMetadataHandler{h}
}
// ServeHTTP fails if the request contains at least one reserved header which
// would be treated as metadata.
func (h reservedMetadataHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if containsReservedMetadata(r.Header) {
writeErrorResponse(w, ErrUnsupportedMetadata, r.URL)
return
}
h.Handler.ServeHTTP(w, r)
}
// containsReservedMetadata returns true if the http.Header contains
// keys which are treated as metadata but are reserved for internal use
// and must not set by clients
func containsReservedMetadata(header http.Header) bool {
for key := range header {
if strings.HasPrefix(key, ReservedMetadataPrefix) {
return true
}
}
return false
}
// Reserved bucket.
const (
minioReservedBucket = "minio"
minioReservedBucketPath = "/" + minioReservedBucket
)
// Adds redirect rules for incoming requests.
type redirectHandler struct {
handler http.Handler
}
func setBrowserRedirectHandler(h http.Handler) http.Handler {
return redirectHandler{handler: h}
}
// Fetch redirect location if urlPath satisfies certain
// criteria. Some special names are considered to be
// redirectable, this is purely internal function and
// serves only limited purpose on redirect-handler for
// browser requests.
func getRedirectLocation(urlPath string) (rLocation string) {
if urlPath == minioReservedBucketPath {
rLocation = minioReservedBucketPath + "/"
}
if contains([]string{
"/",
"/webrpc",
"/login",
"/favicon.ico",
}, urlPath) {
rLocation = minioReservedBucketPath + urlPath
}
return rLocation
}
// guessIsBrowserReq - returns true if the request is browser.
// This implementation just validates user-agent and
// looks for "Mozilla" string. This is no way certifiable
// way to know if the request really came from a browser
// since User-Agent's can be arbitrary. But this is just
// a best effort function.
func guessIsBrowserReq(req *http.Request) bool {
if req == nil {
return false
}
return strings.Contains(req.Header.Get("User-Agent"), "Mozilla")
}
// guessIsHealthCheckReq - returns true if incoming request looks
// like healthcheck request
func guessIsHealthCheckReq(req *http.Request) bool {
if req == nil {
return false
}
aType := getRequestAuthType(req)
return aType == authTypeAnonymous && (req.Method == http.MethodGet || req.Method == http.MethodHead) &&
(req.URL.Path == healthCheckPathPrefix+healthCheckLivenessPath ||
req.URL.Path == healthCheckPathPrefix+healthCheckReadinessPath)
}
// guessIsMetricsReq - returns true if incoming request looks
// like metrics request
func guessIsMetricsReq(req *http.Request) bool {
if req == nil {
return false
}
aType := getRequestAuthType(req)
return aType == authTypeAnonymous &&
req.URL.Path == minioReservedBucketPath+prometheusMetricsPath
}
// guessIsRPCReq - returns true if the request is for an RPC endpoint.
func guessIsRPCReq(req *http.Request) bool {
if req == nil {
return false
}
return req.Method == http.MethodPost
}
func (h redirectHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
aType := getRequestAuthType(r)
// Re-direct only for JWT and anonymous requests from browser.
if aType == authTypeJWT || aType == authTypeAnonymous {
// Re-direction is handled specifically for browser requests.
if guessIsBrowserReq(r) && globalIsBrowserEnabled {
// Fetch the redirect location if any.
redirectLocation := getRedirectLocation(r.URL.Path)
if redirectLocation != "" {
// Employ a temporary re-direct.
http.Redirect(w, r, redirectLocation, http.StatusTemporaryRedirect)
return
}
}
}
h.handler.ServeHTTP(w, r)
}
// Adds Cache-Control header
type cacheControlHandler struct {
handler http.Handler
}
func setBrowserCacheControlHandler(h http.Handler) http.Handler {
return cacheControlHandler{h}
}
func (h cacheControlHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if r.Method == http.MethodGet && guessIsBrowserReq(r) && globalIsBrowserEnabled {
// For all browser requests set appropriate Cache-Control policies
if hasPrefix(r.URL.Path, minioReservedBucketPath+"/") {
if hasSuffix(r.URL.Path, ".js") || r.URL.Path == minioReservedBucketPath+"/favicon.ico" {
// For assets set cache expiry of one year. For each release, the name
// of the asset name will change and hence it can not be served from cache.
w.Header().Set("Cache-Control", "max-age=31536000")
} else {
// For non asset requests we serve index.html which will never be cached.
w.Header().Set("Cache-Control", "no-store")
}
}
}
h.handler.ServeHTTP(w, r)
}
// Check to allow access to the reserved "bucket" `/minio` for Admin
// API requests.
func isAdminReq(r *http.Request) bool {
return strings.HasPrefix(r.URL.Path, adminAPIPathPrefix+"/")
}
// Adds verification for incoming paths.
type minioReservedBucketHandler struct {
handler http.Handler
}
func setReservedBucketHandler(h http.Handler) http.Handler {
return minioReservedBucketHandler{h}
}
func (h minioReservedBucketHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
switch {
case guessIsRPCReq(r), guessIsBrowserReq(r), guessIsHealthCheckReq(r), guessIsMetricsReq(r), isAdminReq(r):
// Allow access to reserved buckets
default:
// For all other requests reject access to reserved
// buckets
bucketName, _ := urlPath2BucketObjectName(r.URL.Path)
if isMinioReservedBucket(bucketName) || isMinioMetaBucket(bucketName) {
writeErrorResponse(w, ErrAllAccessDisabled, r.URL)
return
}
}
h.handler.ServeHTTP(w, r)
}
type timeValidityHandler struct {
handler http.Handler
}
// setTimeValidityHandler to validate parsable time over http header
func setTimeValidityHandler(h http.Handler) http.Handler {
return timeValidityHandler{h}
}
// Supported Amz date formats.
var amzDateFormats = []string{
time.RFC1123,
time.RFC1123Z,
iso8601Format,
// Add new AMZ date formats here.
}
// Supported Amz date headers.
var amzDateHeaders = []string{
"x-amz-date",
"date",
}
// parseAmzDate - parses date string into supported amz date formats.
func parseAmzDate(amzDateStr string) (amzDate time.Time, apiErr APIErrorCode) {
for _, dateFormat := range amzDateFormats {
amzDate, err := time.Parse(dateFormat, amzDateStr)
if err == nil {
return amzDate, ErrNone
}
}
return time.Time{}, ErrMalformedDate
}
// parseAmzDateHeader - parses supported amz date headers, in
// supported amz date formats.
func parseAmzDateHeader(req *http.Request) (time.Time, APIErrorCode) {
for _, amzDateHeader := range amzDateHeaders {
amzDateStr := req.Header.Get(http.CanonicalHeaderKey(amzDateHeader))
if amzDateStr != "" {
return parseAmzDate(amzDateStr)
}
}
// Date header missing.
return time.Time{}, ErrMissingDateHeader
}
func (h timeValidityHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
aType := getRequestAuthType(r)
if aType == authTypeSigned || aType == authTypeSignedV2 || aType == authTypeStreamingSigned {
// Verify if date headers are set, if not reject the request
amzDate, apiErr := parseAmzDateHeader(r)
if apiErr != ErrNone {
// All our internal APIs are sensitive towards Date
// header, for all requests where Date header is not
// present we will reject such clients.
writeErrorResponse(w, apiErr, r.URL)
return
}
// Verify if the request date header is shifted by less than globalMaxSkewTime parameter in the past
// or in the future, reject request otherwise.
curTime := UTCNow()
if curTime.Sub(amzDate) > globalMaxSkewTime || amzDate.Sub(curTime) > globalMaxSkewTime {
writeErrorResponse(w, ErrRequestTimeTooSkewed, r.URL)
return
}
}
h.handler.ServeHTTP(w, r)
}
type resourceHandler struct {
handler http.Handler
}
// List of default allowable HTTP methods.
var defaultAllowableHTTPMethods = []string{
http.MethodGet,
http.MethodPut,
http.MethodHead,
http.MethodPost,
http.MethodDelete,
http.MethodOptions,
}
// setCorsHandler handler for CORS (Cross Origin Resource Sharing)
func setCorsHandler(h http.Handler) http.Handler {
commonS3Headers := []string{
"Date",
"ETag",
"Server",
"Connection",
"Accept-Ranges",
"Content-Range",
"Content-Encoding",
"Content-Length",
"Content-Type",
"x-amz-request-id",
}
c := cors.New(cors.Options{
AllowedOrigins: []string{"*"},
AllowedMethods: defaultAllowableHTTPMethods,
AllowedHeaders: []string{"*"},
ExposedHeaders: commonS3Headers,
AllowCredentials: true,
})
return c.Handler(h)
}
// setIgnoreResourcesHandler -
// Ignore resources handler is wrapper handler used for API request resource validation
// Since we do not support all the S3 queries, it is necessary for us to throw back a
// valid error message indicating that requested feature is not implemented.
func setIgnoreResourcesHandler(h http.Handler) http.Handler {
return resourceHandler{h}
}
// Checks requests for not implemented Bucket resources
func ignoreNotImplementedBucketResources(req *http.Request) bool {
for name := range req.URL.Query() {
// Enable GetBucketACL dummy call specifically.
if name == "acl" && req.Method == http.MethodGet {
return false
}
if notimplementedBucketResourceNames[name] {
return true
}
}
return false
}
// Checks requests for not implemented Object resources
func ignoreNotImplementedObjectResources(req *http.Request) bool {
for name := range req.URL.Query() {
// Enable GetObjectACL dummy call specifically.
if name == "acl" && req.Method == http.MethodGet {
return false
}
if notimplementedObjectResourceNames[name] {
return true
}
}
return false
}
// List of not implemented bucket queries
var notimplementedBucketResourceNames = map[string]bool{
"acl": true,
"cors": true,
"lifecycle": true,
"logging": true,
"replication": true,
"tagging": true,
"versions": true,
"requestPayment": true,
"versioning": true,
"website": true,
"inventory": true,
"metrics": true,
"accelerate": true,
}
// List of not implemented object queries
var notimplementedObjectResourceNames = map[string]bool{
"torrent": true,
"acl": true,
"policy": true,
"tagging": true,
"restore": true,
"select": true,
}
// Resource handler ServeHTTP() wrapper
func (h resourceHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
bucketName, objectName := urlPath2BucketObjectName(r.URL.Path)
// If bucketName is present and not objectName check for bucket level resource queries.
if bucketName != "" && objectName == "" {
if ignoreNotImplementedBucketResources(r) {
writeErrorResponse(w, ErrNotImplemented, r.URL)
return
}
}
// If bucketName and objectName are present check for its resource queries.
if bucketName != "" && objectName != "" {
if ignoreNotImplementedObjectResources(r) {
writeErrorResponse(w, ErrNotImplemented, r.URL)
return
}
}
// A put method on path "/" doesn't make sense, ignore it.
if r.Method == http.MethodPut && r.URL.Path == "/" {
writeErrorResponse(w, ErrNotImplemented, r.URL)
return
}
// Serve HTTP.
h.handler.ServeHTTP(w, r)
}
// httpResponseRecorder wraps http.ResponseWriter
// to record some useful http response data.
type httpResponseRecorder struct {
http.ResponseWriter
respStatusCode int
}
// Wraps ResponseWriter's Write()
func (rww *httpResponseRecorder) Write(b []byte) (int, error) {
return rww.ResponseWriter.Write(b)
}
// Wraps ResponseWriter's Flush()
func (rww *httpResponseRecorder) Flush() {
rww.ResponseWriter.(http.Flusher).Flush()
}
// Wraps ResponseWriter's WriteHeader() and record
// the response status code
func (rww *httpResponseRecorder) WriteHeader(httpCode int) {
rww.respStatusCode = httpCode
rww.ResponseWriter.WriteHeader(httpCode)
}
func (rww *httpResponseRecorder) Hijack() (net.Conn, *bufio.ReadWriter, error) {
return rww.ResponseWriter.(http.Hijacker).Hijack()
}
// httpStatsHandler definition: gather HTTP statistics
type httpStatsHandler struct {
handler http.Handler
}
// setHttpStatsHandler sets a http Stats Handler
func setHTTPStatsHandler(h http.Handler) http.Handler {
return httpStatsHandler{handler: h}
}
func (h httpStatsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Wraps w to record http response information
ww := &httpResponseRecorder{ResponseWriter: w}
// Time start before the call is about to start.
tBefore := UTCNow()
// Execute the request
h.handler.ServeHTTP(ww, r)
// Time after call has completed.
tAfter := UTCNow()
// Time duration in secs since the call started.
//
// We don't need to do nanosecond precision in this
// simply for the fact that it is not human readable.
durationSecs := tAfter.Sub(tBefore).Seconds()
// Update http statistics
globalHTTPStats.updateStats(r, ww, durationSecs)
}
// pathValidityHandler validates all the incoming paths for
// any bad components and rejects them.
type pathValidityHandler struct {
handler http.Handler
}
func setPathValidityHandler(h http.Handler) http.Handler {
return pathValidityHandler{handler: h}
}
// Bad path components to be rejected by the path validity handler.
const (
dotdotComponent = ".."
dotComponent = "."
)
// Check if the incoming path has bad path components,
// such as ".." and "."
func hasBadPathComponent(path string) bool {
path = strings.TrimSpace(path)
for _, p := range strings.Split(path, slashSeparator) {
switch strings.TrimSpace(p) {
case dotdotComponent:
return true
case dotComponent:
return true
}
}
return false
}
func (h pathValidityHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Check for bad components in URL path.
if hasBadPathComponent(r.URL.Path) {
writeErrorResponse(w, ErrInvalidResourceName, r.URL)
return
}
// Check for bad components in URL query values.
for _, vv := range r.URL.Query() {
for _, v := range vv {
if hasBadPathComponent(v) {
writeErrorResponse(w, ErrInvalidResourceName, r.URL)
return
}
}
}
h.handler.ServeHTTP(w, r)
}
// To forward the path style requests on a bucket to the right
// configured server, bucket to IP configuration is obtained
// from centralized etcd configuration service.
type bucketForwardingHandler struct {
fwd *handlers.Forwarder
handler http.Handler
}
func (f bucketForwardingHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if globalDNSConfig == nil || globalDomainName == "" || guessIsBrowserReq(r) || guessIsHealthCheckReq(r) || guessIsMetricsReq(r) || guessIsRPCReq(r) {
f.handler.ServeHTTP(w, r)
return
}
bucket, object := urlPath2BucketObjectName(r.URL.Path)
// ListBucket requests should be handled at current endpoint as
// all buckets data can be fetched from here.
if r.Method == http.MethodGet && bucket == "" && object == "" {
f.handler.ServeHTTP(w, r)
return
}
// MakeBucket requests should be handled at current endpoint
if r.Method == http.MethodPut && bucket != "" && object == "" {
f.handler.ServeHTTP(w, r)
return
}
// CopyObject requests should be handled at current endpoint as path style
// requests have target bucket and object in URI and source details are in
// header fields
if r.Method == http.MethodPut && r.Header.Get("X-Amz-Copy-Source") != "" {
f.handler.ServeHTTP(w, r)
return
}
sr, err := globalDNSConfig.Get(bucket)
if err != nil {
if err == dns.ErrNoEntriesFound {
writeErrorResponse(w, ErrNoSuchBucket, r.URL)
} else {
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
}
return
}
if globalDomainIPs.Intersection(set.CreateStringSet(getHostsSlice(sr)...)).IsEmpty() {
host, port := getRandomHostPort(sr)
r.URL.Scheme = "http"
if globalIsSSL {
r.URL.Scheme = "https"
}
r.URL.Host = fmt.Sprintf("%s:%d", host, port)
f.fwd.ServeHTTP(w, r)
return
}
f.handler.ServeHTTP(w, r)
}
// setBucketForwardingHandler middleware forwards the path style requests
// on a bucket to the right bucket location, bucket to IP configuration
// is obtained from centralized etcd configuration service.
func setBucketForwardingHandler(h http.Handler) http.Handler {
fwd := handlers.NewForwarder(&handlers.Forwarder{
PassHost: true,
RoundTripper: NewCustomHTTPTransport(),
})
return bucketForwardingHandler{fwd, h}
}
// setRateLimitHandler middleware limits the throughput to h using a
// rate.Limiter token bucket configured with maxOpenFileLimit and
// burst set to 1. The request will idle for up to 1*time.Second.
// If the limiter detects the deadline will be exceeded, the request is
// canceled immediately.
func setRateLimitHandler(h http.Handler) http.Handler {
_, maxLimit, err := sys.GetMaxOpenFileLimit()
logger.FatalIf(err, "Unable to get maximum open file limit", context.Background())
// Burst value is set to 1 to allow only maxOpenFileLimit
// requests to happen at once.
l := rate.NewLimiter(rate.Limit(maxLimit), 1)
return rateLimit{l, h}
}
type rateLimit struct {
*rate.Limiter
handler http.Handler
}
func (l rateLimit) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// create a new context from the request with the wait timeout
ctx, cancel := context.WithTimeout(r.Context(), 1*time.Second)
defer cancel() // always cancel the context!
// Wait errors out if the request cannot be processed within
// the deadline. time/rate tries to reserve a slot if possible
// with in the given duration if it's not possible then Wait(ctx)
// returns an error and we cancel the request with ErrSlowDown
// error message to the client. This context wait also ensures
// requests doomed to fail are terminated early, preventing a
// potential pileup on the server.
if err := l.Wait(ctx); err != nil {
// Send an S3 compatible error, SlowDown.
writeErrorResponse(w, ErrSlowDown, r.URL)
return
}
l.handler.ServeHTTP(w, r)
}
// requestIDHeaderHandler sets x-amz-request-id header.
// Previously, this value was set right before a response
// was sent to the client.So, logger and Error response XML
// were not using this value.
// This is set here so that this header can be logged as
// part of the log entry and Error response XML.
type requestIDHeaderHandler struct {
handler http.Handler
}
func addrequestIDHeader(h http.Handler) http.Handler {
return requestIDHeaderHandler{handler: h}
}
func (s requestIDHeaderHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Set unique request ID for each response.
w.Header().Set(responseRequestIDKey, mustGetRequestID(UTCNow()))
s.handler.ServeHTTP(w, r)
}
type securityHeaderHandler struct {
handler http.Handler
}
func addSecurityHeaders(h http.Handler) http.Handler {
return securityHeaderHandler{handler: h}
}
func (s securityHeaderHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
header := w.Header()
header.Set("X-XSS-Protection", "1; mode=block") // Prevents against XSS attacks
header.Set("Content-Security-Policy", "block-all-mixed-content") // prevent mixed (HTTP / HTTPS content)
s.handler.ServeHTTP(w, r)
}
// criticalErrorHandler handles critical server failures caused by
// `panic(logger.ErrCritical)` as done by `logger.CriticalIf`.
//
// It should be always the first / highest HTTP handler.
type criticalErrorHandler struct{ handler http.Handler }
func (h criticalErrorHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
defer func() {
if err := recover(); err == logger.ErrCritical { // handle
writeErrorResponse(w, ErrInternalError, r.URL)
} else if err != nil {
panic(err) // forward other panic calls
}
}()
h.handler.ServeHTTP(w, r)
}