1114 lines
30 KiB
Go
1114 lines
30 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package http
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import (
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"bufio"
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"bytes"
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"errors"
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"fmt"
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"io"
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"net/http/httptrace"
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"net/http/internal"
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"net/http/internal/ascii"
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"net/textproto"
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"reflect"
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"sort"
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"strconv"
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"strings"
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"sync"
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"time"
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"golang.org/x/net/http/httpguts"
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)
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// ErrLineTooLong is returned when reading request or response bodies
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// with malformed chunked encoding.
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var ErrLineTooLong = internal.ErrLineTooLong
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type errorReader struct {
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err error
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}
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func (r errorReader) Read(p []byte) (n int, err error) {
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return 0, r.err
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}
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type byteReader struct {
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b byte
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done bool
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}
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func (br *byteReader) Read(p []byte) (n int, err error) {
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if br.done {
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return 0, io.EOF
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}
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if len(p) == 0 {
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return 0, nil
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}
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br.done = true
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p[0] = br.b
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return 1, io.EOF
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}
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// transferWriter inspects the fields of a user-supplied Request or Response,
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// sanitizes them without changing the user object and provides methods for
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// writing the respective header, body and trailer in wire format.
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type transferWriter struct {
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Method string
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Body io.Reader
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BodyCloser io.Closer
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ResponseToHEAD bool
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ContentLength int64 // -1 means unknown, 0 means exactly none
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Close bool
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TransferEncoding []string
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Header Header
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Trailer Header
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IsResponse bool
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bodyReadError error // any non-EOF error from reading Body
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FlushHeaders bool // flush headers to network before body
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ByteReadCh chan readResult // non-nil if probeRequestBody called
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}
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func newTransferWriter(r any) (t *transferWriter, err error) {
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t = &transferWriter{}
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// Extract relevant fields
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atLeastHTTP11 := false
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switch rr := r.(type) {
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case *Request:
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if rr.ContentLength != 0 && rr.Body == nil {
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return nil, fmt.Errorf("http: Request.ContentLength=%d with nil Body", rr.ContentLength)
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}
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t.Method = valueOrDefault(rr.Method, "GET")
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t.Close = rr.Close
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t.TransferEncoding = rr.TransferEncoding
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t.Header = rr.Header
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t.Trailer = rr.Trailer
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t.Body = rr.Body
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t.BodyCloser = rr.Body
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t.ContentLength = rr.outgoingLength()
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if t.ContentLength < 0 && len(t.TransferEncoding) == 0 && t.shouldSendChunkedRequestBody() {
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t.TransferEncoding = []string{"chunked"}
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}
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// If there's a body, conservatively flush the headers
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// to any bufio.Writer we're writing to, just in case
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// the server needs the headers early, before we copy
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// the body and possibly block. We make an exception
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// for the common standard library in-memory types,
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// though, to avoid unnecessary TCP packets on the
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// wire. (Issue 22088.)
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if t.ContentLength != 0 && !isKnownInMemoryReader(t.Body) {
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t.FlushHeaders = true
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}
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atLeastHTTP11 = true // Transport requests are always 1.1 or 2.0
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case *Response:
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t.IsResponse = true
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if rr.Request != nil {
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t.Method = rr.Request.Method
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}
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t.Body = rr.Body
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t.BodyCloser = rr.Body
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t.ContentLength = rr.ContentLength
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t.Close = rr.Close
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t.TransferEncoding = rr.TransferEncoding
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t.Header = rr.Header
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t.Trailer = rr.Trailer
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atLeastHTTP11 = rr.ProtoAtLeast(1, 1)
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t.ResponseToHEAD = noResponseBodyExpected(t.Method)
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}
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// Sanitize Body,ContentLength,TransferEncoding
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if t.ResponseToHEAD {
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t.Body = nil
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if chunked(t.TransferEncoding) {
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t.ContentLength = -1
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}
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} else {
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if !atLeastHTTP11 || t.Body == nil {
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t.TransferEncoding = nil
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}
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if chunked(t.TransferEncoding) {
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t.ContentLength = -1
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} else if t.Body == nil { // no chunking, no body
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t.ContentLength = 0
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}
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}
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// Sanitize Trailer
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if !chunked(t.TransferEncoding) {
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t.Trailer = nil
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}
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return t, nil
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}
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// shouldSendChunkedRequestBody reports whether we should try to send a
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// chunked request body to the server. In particular, the case we really
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// want to prevent is sending a GET or other typically-bodyless request to a
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// server with a chunked body when the body has zero bytes, since GETs with
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// bodies (while acceptable according to specs), even zero-byte chunked
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// bodies, are approximately never seen in the wild and confuse most
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// servers. See Issue 18257, as one example.
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//
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// The only reason we'd send such a request is if the user set the Body to a
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// non-nil value (say, io.NopCloser(bytes.NewReader(nil))) and didn't
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// set ContentLength, or NewRequest set it to -1 (unknown), so then we assume
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// there's bytes to send.
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//
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// This code tries to read a byte from the Request.Body in such cases to see
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// whether the body actually has content (super rare) or is actually just
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// a non-nil content-less ReadCloser (the more common case). In that more
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// common case, we act as if their Body were nil instead, and don't send
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// a body.
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func (t *transferWriter) shouldSendChunkedRequestBody() bool {
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// Note that t.ContentLength is the corrected content length
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// from rr.outgoingLength, so 0 actually means zero, not unknown.
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if t.ContentLength >= 0 || t.Body == nil { // redundant checks; caller did them
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return false
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}
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if t.Method == "CONNECT" {
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return false
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}
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if requestMethodUsuallyLacksBody(t.Method) {
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// Only probe the Request.Body for GET/HEAD/DELETE/etc
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// requests, because it's only those types of requests
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// that confuse servers.
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t.probeRequestBody() // adjusts t.Body, t.ContentLength
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return t.Body != nil
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}
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// For all other request types (PUT, POST, PATCH, or anything
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// made-up we've never heard of), assume it's normal and the server
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// can deal with a chunked request body. Maybe we'll adjust this
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// later.
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return true
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}
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// probeRequestBody reads a byte from t.Body to see whether it's empty
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// (returns io.EOF right away).
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//
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// But because we've had problems with this blocking users in the past
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// (issue 17480) when the body is a pipe (perhaps waiting on the response
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// headers before the pipe is fed data), we need to be careful and bound how
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// long we wait for it. This delay will only affect users if all the following
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// are true:
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// * the request body blocks
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// * the content length is not set (or set to -1)
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// * the method doesn't usually have a body (GET, HEAD, DELETE, ...)
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// * there is no transfer-encoding=chunked already set.
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// In other words, this delay will not normally affect anybody, and there
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// are workarounds if it does.
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func (t *transferWriter) probeRequestBody() {
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t.ByteReadCh = make(chan readResult, 1)
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go func(body io.Reader) {
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var buf [1]byte
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var rres readResult
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rres.n, rres.err = body.Read(buf[:])
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if rres.n == 1 {
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rres.b = buf[0]
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}
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t.ByteReadCh <- rres
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close(t.ByteReadCh)
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}(t.Body)
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timer := time.NewTimer(200 * time.Millisecond)
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select {
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case rres := <-t.ByteReadCh:
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timer.Stop()
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if rres.n == 0 && rres.err == io.EOF {
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// It was empty.
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t.Body = nil
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t.ContentLength = 0
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} else if rres.n == 1 {
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if rres.err != nil {
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t.Body = io.MultiReader(&byteReader{b: rres.b}, errorReader{rres.err})
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} else {
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t.Body = io.MultiReader(&byteReader{b: rres.b}, t.Body)
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}
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} else if rres.err != nil {
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t.Body = errorReader{rres.err}
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}
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case <-timer.C:
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// Too slow. Don't wait. Read it later, and keep
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// assuming that this is ContentLength == -1
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// (unknown), which means we'll send a
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// "Transfer-Encoding: chunked" header.
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t.Body = io.MultiReader(finishAsyncByteRead{t}, t.Body)
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// Request that Request.Write flush the headers to the
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// network before writing the body, since our body may not
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// become readable until it's seen the response headers.
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t.FlushHeaders = true
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}
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}
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func noResponseBodyExpected(requestMethod string) bool {
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return requestMethod == "HEAD"
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}
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func (t *transferWriter) shouldSendContentLength() bool {
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if chunked(t.TransferEncoding) {
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return false
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}
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if t.ContentLength > 0 {
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return true
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}
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if t.ContentLength < 0 {
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return false
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}
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// Many servers expect a Content-Length for these methods
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if t.Method == "POST" || t.Method == "PUT" || t.Method == "PATCH" {
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return true
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}
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if t.ContentLength == 0 && isIdentity(t.TransferEncoding) {
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if t.Method == "GET" || t.Method == "HEAD" {
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return false
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}
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return true
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}
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return false
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}
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func (t *transferWriter) writeHeader(w io.Writer, trace *httptrace.ClientTrace) error {
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if t.Close && !hasToken(t.Header.get("Connection"), "close") {
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if _, err := io.WriteString(w, "Connection: close\r\n"); err != nil {
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return err
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}
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if trace != nil && trace.WroteHeaderField != nil {
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trace.WroteHeaderField("Connection", []string{"close"})
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}
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}
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// Write Content-Length and/or Transfer-Encoding whose values are a
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// function of the sanitized field triple (Body, ContentLength,
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// TransferEncoding)
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if t.shouldSendContentLength() {
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if _, err := io.WriteString(w, "Content-Length: "); err != nil {
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return err
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}
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if _, err := io.WriteString(w, strconv.FormatInt(t.ContentLength, 10)+"\r\n"); err != nil {
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return err
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}
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if trace != nil && trace.WroteHeaderField != nil {
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trace.WroteHeaderField("Content-Length", []string{strconv.FormatInt(t.ContentLength, 10)})
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}
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} else if chunked(t.TransferEncoding) {
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if _, err := io.WriteString(w, "Transfer-Encoding: chunked\r\n"); err != nil {
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return err
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}
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if trace != nil && trace.WroteHeaderField != nil {
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trace.WroteHeaderField("Transfer-Encoding", []string{"chunked"})
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}
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}
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// Write Trailer header
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if t.Trailer != nil {
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keys := make([]string, 0, len(t.Trailer))
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for k := range t.Trailer {
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k = CanonicalHeaderKey(k)
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switch k {
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case "Transfer-Encoding", "Trailer", "Content-Length":
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return badStringError("invalid Trailer key", k)
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}
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keys = append(keys, k)
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}
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if len(keys) > 0 {
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sort.Strings(keys)
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// TODO: could do better allocation-wise here, but trailers are rare,
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// so being lazy for now.
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if _, err := io.WriteString(w, "Trailer: "+strings.Join(keys, ",")+"\r\n"); err != nil {
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return err
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}
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if trace != nil && trace.WroteHeaderField != nil {
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trace.WroteHeaderField("Trailer", keys)
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}
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}
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}
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return nil
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}
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// always closes t.BodyCloser
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func (t *transferWriter) writeBody(w io.Writer) (err error) {
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var ncopy int64
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closed := false
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defer func() {
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if closed || t.BodyCloser == nil {
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return
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}
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if closeErr := t.BodyCloser.Close(); closeErr != nil && err == nil {
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err = closeErr
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}
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}()
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// Write body. We "unwrap" the body first if it was wrapped in a
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// nopCloser or readTrackingBody. This is to ensure that we can take advantage of
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// OS-level optimizations in the event that the body is an
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// *os.File.
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if t.Body != nil {
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var body = t.unwrapBody()
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if chunked(t.TransferEncoding) {
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if bw, ok := w.(*bufio.Writer); ok && !t.IsResponse {
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w = &internal.FlushAfterChunkWriter{Writer: bw}
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}
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cw := internal.NewChunkedWriter(w)
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_, err = t.doBodyCopy(cw, body)
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if err == nil {
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err = cw.Close()
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}
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} else if t.ContentLength == -1 {
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dst := w
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if t.Method == "CONNECT" {
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dst = bufioFlushWriter{dst}
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}
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ncopy, err = t.doBodyCopy(dst, body)
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} else {
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ncopy, err = t.doBodyCopy(w, io.LimitReader(body, t.ContentLength))
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if err != nil {
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return err
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}
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var nextra int64
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nextra, err = t.doBodyCopy(io.Discard, body)
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ncopy += nextra
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}
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if err != nil {
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return err
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}
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}
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if t.BodyCloser != nil {
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closed = true
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if err := t.BodyCloser.Close(); err != nil {
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return err
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}
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}
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if !t.ResponseToHEAD && t.ContentLength != -1 && t.ContentLength != ncopy {
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return fmt.Errorf("http: ContentLength=%d with Body length %d",
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t.ContentLength, ncopy)
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}
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if chunked(t.TransferEncoding) {
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// Write Trailer header
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if t.Trailer != nil {
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if err := t.Trailer.Write(w); err != nil {
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return err
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}
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}
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// Last chunk, empty trailer
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_, err = io.WriteString(w, "\r\n")
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}
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return err
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}
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// doBodyCopy wraps a copy operation, with any resulting error also
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// being saved in bodyReadError.
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//
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// This function is only intended for use in writeBody.
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func (t *transferWriter) doBodyCopy(dst io.Writer, src io.Reader) (n int64, err error) {
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n, err = io.Copy(dst, src)
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if err != nil && err != io.EOF {
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t.bodyReadError = err
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}
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return
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}
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// unwrapBodyReader unwraps the body's inner reader if it's a
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// nopCloser. This is to ensure that body writes sourced from local
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// files (*os.File types) are properly optimized.
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//
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// This function is only intended for use in writeBody.
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func (t *transferWriter) unwrapBody() io.Reader {
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if reflect.TypeOf(t.Body) == nopCloserType {
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return reflect.ValueOf(t.Body).Field(0).Interface().(io.Reader)
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}
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if r, ok := t.Body.(*readTrackingBody); ok {
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r.didRead = true
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return r.ReadCloser
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}
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return t.Body
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}
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type transferReader struct {
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// Input
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Header Header
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StatusCode int
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RequestMethod string
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ProtoMajor int
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ProtoMinor int
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// Output
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Body io.ReadCloser
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ContentLength int64
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Chunked bool
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Close bool
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Trailer Header
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}
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func (t *transferReader) protoAtLeast(m, n int) bool {
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return t.ProtoMajor > m || (t.ProtoMajor == m && t.ProtoMinor >= n)
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}
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// bodyAllowedForStatus reports whether a given response status code
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// permits a body. See RFC 7230, section 3.3.
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func bodyAllowedForStatus(status int) bool {
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switch {
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case status >= 100 && status <= 199:
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return false
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case status == 204:
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return false
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case status == 304:
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return false
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}
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return true
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}
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var (
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suppressedHeaders304 = []string{"Content-Type", "Content-Length", "Transfer-Encoding"}
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suppressedHeadersNoBody = []string{"Content-Length", "Transfer-Encoding"}
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)
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func suppressedHeaders(status int) []string {
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switch {
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case status == 304:
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// RFC 7232 section 4.1
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return suppressedHeaders304
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case !bodyAllowedForStatus(status):
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return suppressedHeadersNoBody
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}
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return nil
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}
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// msg is *Request or *Response.
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func readTransfer(msg any, r *bufio.Reader) (err error) {
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t := &transferReader{RequestMethod: "GET"}
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// Unify input
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isResponse := false
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switch rr := msg.(type) {
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case *Response:
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t.Header = rr.Header
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t.StatusCode = rr.StatusCode
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t.ProtoMajor = rr.ProtoMajor
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t.ProtoMinor = rr.ProtoMinor
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t.Close = shouldClose(t.ProtoMajor, t.ProtoMinor, t.Header, true)
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isResponse = true
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if rr.Request != nil {
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t.RequestMethod = rr.Request.Method
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}
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case *Request:
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t.Header = rr.Header
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t.RequestMethod = rr.Method
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t.ProtoMajor = rr.ProtoMajor
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t.ProtoMinor = rr.ProtoMinor
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// Transfer semantics for Requests are exactly like those for
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// Responses with status code 200, responding to a GET method
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t.StatusCode = 200
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t.Close = rr.Close
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default:
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panic("unexpected type")
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}
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// Default to HTTP/1.1
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if t.ProtoMajor == 0 && t.ProtoMinor == 0 {
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t.ProtoMajor, t.ProtoMinor = 1, 1
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}
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// Transfer-Encoding: chunked, and overriding Content-Length.
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if err := t.parseTransferEncoding(); err != nil {
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return err
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}
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realLength, err := fixLength(isResponse, t.StatusCode, t.RequestMethod, t.Header, t.Chunked)
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if err != nil {
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return err
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}
|
|
if isResponse && t.RequestMethod == "HEAD" {
|
|
if n, err := parseContentLength(t.Header.get("Content-Length")); err != nil {
|
|
return err
|
|
} else {
|
|
t.ContentLength = n
|
|
}
|
|
} else {
|
|
t.ContentLength = realLength
|
|
}
|
|
|
|
// Trailer
|
|
t.Trailer, err = fixTrailer(t.Header, t.Chunked)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// If there is no Content-Length or chunked Transfer-Encoding on a *Response
|
|
// and the status is not 1xx, 204 or 304, then the body is unbounded.
|
|
// See RFC 7230, section 3.3.
|
|
switch msg.(type) {
|
|
case *Response:
|
|
if realLength == -1 && !t.Chunked && bodyAllowedForStatus(t.StatusCode) {
|
|
// Unbounded body.
|
|
t.Close = true
|
|
}
|
|
}
|
|
|
|
// Prepare body reader. ContentLength < 0 means chunked encoding
|
|
// or close connection when finished, since multipart is not supported yet
|
|
switch {
|
|
case t.Chunked:
|
|
if noResponseBodyExpected(t.RequestMethod) || !bodyAllowedForStatus(t.StatusCode) {
|
|
t.Body = NoBody
|
|
} else {
|
|
t.Body = &body{src: internal.NewChunkedReader(r), hdr: msg, r: r, closing: t.Close}
|
|
}
|
|
case realLength == 0:
|
|
t.Body = NoBody
|
|
case realLength > 0:
|
|
t.Body = &body{src: io.LimitReader(r, realLength), closing: t.Close}
|
|
default:
|
|
// realLength < 0, i.e. "Content-Length" not mentioned in header
|
|
if t.Close {
|
|
// Close semantics (i.e. HTTP/1.0)
|
|
t.Body = &body{src: r, closing: t.Close}
|
|
} else {
|
|
// Persistent connection (i.e. HTTP/1.1)
|
|
t.Body = NoBody
|
|
}
|
|
}
|
|
|
|
// Unify output
|
|
switch rr := msg.(type) {
|
|
case *Request:
|
|
rr.Body = t.Body
|
|
rr.ContentLength = t.ContentLength
|
|
if t.Chunked {
|
|
rr.TransferEncoding = []string{"chunked"}
|
|
}
|
|
rr.Close = t.Close
|
|
rr.Trailer = t.Trailer
|
|
case *Response:
|
|
rr.Body = t.Body
|
|
rr.ContentLength = t.ContentLength
|
|
if t.Chunked {
|
|
rr.TransferEncoding = []string{"chunked"}
|
|
}
|
|
rr.Close = t.Close
|
|
rr.Trailer = t.Trailer
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Checks whether chunked is part of the encodings stack
|
|
func chunked(te []string) bool { return len(te) > 0 && te[0] == "chunked" }
|
|
|
|
// Checks whether the encoding is explicitly "identity".
|
|
func isIdentity(te []string) bool { return len(te) == 1 && te[0] == "identity" }
|
|
|
|
// unsupportedTEError reports unsupported transfer-encodings.
|
|
type unsupportedTEError struct {
|
|
err string
|
|
}
|
|
|
|
func (uste *unsupportedTEError) Error() string {
|
|
return uste.err
|
|
}
|
|
|
|
// isUnsupportedTEError checks if the error is of type
|
|
// unsupportedTEError. It is usually invoked with a non-nil err.
|
|
func isUnsupportedTEError(err error) bool {
|
|
_, ok := err.(*unsupportedTEError)
|
|
return ok
|
|
}
|
|
|
|
// parseTransferEncoding sets t.Chunked based on the Transfer-Encoding header.
|
|
func (t *transferReader) parseTransferEncoding() error {
|
|
raw, present := t.Header["Transfer-Encoding"]
|
|
if !present {
|
|
return nil
|
|
}
|
|
delete(t.Header, "Transfer-Encoding")
|
|
|
|
// Issue 12785; ignore Transfer-Encoding on HTTP/1.0 requests.
|
|
if !t.protoAtLeast(1, 1) {
|
|
return nil
|
|
}
|
|
|
|
// Like nginx, we only support a single Transfer-Encoding header field, and
|
|
// only if set to "chunked". This is one of the most security sensitive
|
|
// surfaces in HTTP/1.1 due to the risk of request smuggling, so we keep it
|
|
// strict and simple.
|
|
if len(raw) != 1 {
|
|
return &unsupportedTEError{fmt.Sprintf("too many transfer encodings: %q", raw)}
|
|
}
|
|
if !ascii.EqualFold(textproto.TrimString(raw[0]), "chunked") {
|
|
return &unsupportedTEError{fmt.Sprintf("unsupported transfer encoding: %q", raw[0])}
|
|
}
|
|
|
|
// RFC 7230 3.3.2 says "A sender MUST NOT send a Content-Length header field
|
|
// in any message that contains a Transfer-Encoding header field."
|
|
//
|
|
// but also: "If a message is received with both a Transfer-Encoding and a
|
|
// Content-Length header field, the Transfer-Encoding overrides the
|
|
// Content-Length. Such a message might indicate an attempt to perform
|
|
// request smuggling (Section 9.5) or response splitting (Section 9.4) and
|
|
// ought to be handled as an error. A sender MUST remove the received
|
|
// Content-Length field prior to forwarding such a message downstream."
|
|
//
|
|
// Reportedly, these appear in the wild.
|
|
delete(t.Header, "Content-Length")
|
|
|
|
t.Chunked = true
|
|
return nil
|
|
}
|
|
|
|
// Determine the expected body length, using RFC 7230 Section 3.3. This
|
|
// function is not a method, because ultimately it should be shared by
|
|
// ReadResponse and ReadRequest.
|
|
func fixLength(isResponse bool, status int, requestMethod string, header Header, chunked bool) (int64, error) {
|
|
isRequest := !isResponse
|
|
contentLens := header["Content-Length"]
|
|
|
|
// Hardening against HTTP request smuggling
|
|
if len(contentLens) > 1 {
|
|
// Per RFC 7230 Section 3.3.2, prevent multiple
|
|
// Content-Length headers if they differ in value.
|
|
// If there are dups of the value, remove the dups.
|
|
// See Issue 16490.
|
|
first := textproto.TrimString(contentLens[0])
|
|
for _, ct := range contentLens[1:] {
|
|
if first != textproto.TrimString(ct) {
|
|
return 0, fmt.Errorf("http: message cannot contain multiple Content-Length headers; got %q", contentLens)
|
|
}
|
|
}
|
|
|
|
// deduplicate Content-Length
|
|
header.Del("Content-Length")
|
|
header.Add("Content-Length", first)
|
|
|
|
contentLens = header["Content-Length"]
|
|
}
|
|
|
|
// Logic based on response type or status
|
|
if noResponseBodyExpected(requestMethod) {
|
|
// For HTTP requests, as part of hardening against request
|
|
// smuggling (RFC 7230), don't allow a Content-Length header for
|
|
// methods which don't permit bodies. As an exception, allow
|
|
// exactly one Content-Length header if its value is "0".
|
|
if isRequest && len(contentLens) > 0 && !(len(contentLens) == 1 && contentLens[0] == "0") {
|
|
return 0, fmt.Errorf("http: method cannot contain a Content-Length; got %q", contentLens)
|
|
}
|
|
return 0, nil
|
|
}
|
|
if status/100 == 1 {
|
|
return 0, nil
|
|
}
|
|
switch status {
|
|
case 204, 304:
|
|
return 0, nil
|
|
}
|
|
|
|
// Logic based on Transfer-Encoding
|
|
if chunked {
|
|
return -1, nil
|
|
}
|
|
|
|
// Logic based on Content-Length
|
|
var cl string
|
|
if len(contentLens) == 1 {
|
|
cl = textproto.TrimString(contentLens[0])
|
|
}
|
|
if cl != "" {
|
|
n, err := parseContentLength(cl)
|
|
if err != nil {
|
|
return -1, err
|
|
}
|
|
return n, nil
|
|
}
|
|
header.Del("Content-Length")
|
|
|
|
if isRequest {
|
|
// RFC 7230 neither explicitly permits nor forbids an
|
|
// entity-body on a GET request so we permit one if
|
|
// declared, but we default to 0 here (not -1 below)
|
|
// if there's no mention of a body.
|
|
// Likewise, all other request methods are assumed to have
|
|
// no body if neither Transfer-Encoding chunked nor a
|
|
// Content-Length are set.
|
|
return 0, nil
|
|
}
|
|
|
|
// Body-EOF logic based on other methods (like closing, or chunked coding)
|
|
return -1, nil
|
|
}
|
|
|
|
// Determine whether to hang up after sending a request and body, or
|
|
// receiving a response and body
|
|
// 'header' is the request headers
|
|
func shouldClose(major, minor int, header Header, removeCloseHeader bool) bool {
|
|
if major < 1 {
|
|
return true
|
|
}
|
|
|
|
conv := header["Connection"]
|
|
hasClose := httpguts.HeaderValuesContainsToken(conv, "close")
|
|
if major == 1 && minor == 0 {
|
|
return hasClose || !httpguts.HeaderValuesContainsToken(conv, "keep-alive")
|
|
}
|
|
|
|
if hasClose && removeCloseHeader {
|
|
header.Del("Connection")
|
|
}
|
|
|
|
return hasClose
|
|
}
|
|
|
|
// Parse the trailer header
|
|
func fixTrailer(header Header, chunked bool) (Header, error) {
|
|
vv, ok := header["Trailer"]
|
|
if !ok {
|
|
return nil, nil
|
|
}
|
|
if !chunked {
|
|
// Trailer and no chunking:
|
|
// this is an invalid use case for trailer header.
|
|
// Nevertheless, no error will be returned and we
|
|
// let users decide if this is a valid HTTP message.
|
|
// The Trailer header will be kept in Response.Header
|
|
// but not populate Response.Trailer.
|
|
// See issue #27197.
|
|
return nil, nil
|
|
}
|
|
header.Del("Trailer")
|
|
|
|
trailer := make(Header)
|
|
var err error
|
|
for _, v := range vv {
|
|
foreachHeaderElement(v, func(key string) {
|
|
key = CanonicalHeaderKey(key)
|
|
switch key {
|
|
case "Transfer-Encoding", "Trailer", "Content-Length":
|
|
if err == nil {
|
|
err = badStringError("bad trailer key", key)
|
|
return
|
|
}
|
|
}
|
|
trailer[key] = nil
|
|
})
|
|
}
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if len(trailer) == 0 {
|
|
return nil, nil
|
|
}
|
|
return trailer, nil
|
|
}
|
|
|
|
// body turns a Reader into a ReadCloser.
|
|
// Close ensures that the body has been fully read
|
|
// and then reads the trailer if necessary.
|
|
type body struct {
|
|
src io.Reader
|
|
hdr any // non-nil (Response or Request) value means read trailer
|
|
r *bufio.Reader // underlying wire-format reader for the trailer
|
|
closing bool // is the connection to be closed after reading body?
|
|
doEarlyClose bool // whether Close should stop early
|
|
|
|
mu sync.Mutex // guards following, and calls to Read and Close
|
|
sawEOF bool
|
|
closed bool
|
|
earlyClose bool // Close called and we didn't read to the end of src
|
|
onHitEOF func() // if non-nil, func to call when EOF is Read
|
|
}
|
|
|
|
// ErrBodyReadAfterClose is returned when reading a Request or Response
|
|
// Body after the body has been closed. This typically happens when the body is
|
|
// read after an HTTP Handler calls WriteHeader or Write on its
|
|
// ResponseWriter.
|
|
var ErrBodyReadAfterClose = errors.New("http: invalid Read on closed Body")
|
|
|
|
func (b *body) Read(p []byte) (n int, err error) {
|
|
b.mu.Lock()
|
|
defer b.mu.Unlock()
|
|
if b.closed {
|
|
return 0, ErrBodyReadAfterClose
|
|
}
|
|
return b.readLocked(p)
|
|
}
|
|
|
|
// Must hold b.mu.
|
|
func (b *body) readLocked(p []byte) (n int, err error) {
|
|
if b.sawEOF {
|
|
return 0, io.EOF
|
|
}
|
|
n, err = b.src.Read(p)
|
|
|
|
if err == io.EOF {
|
|
b.sawEOF = true
|
|
// Chunked case. Read the trailer.
|
|
if b.hdr != nil {
|
|
if e := b.readTrailer(); e != nil {
|
|
err = e
|
|
// Something went wrong in the trailer, we must not allow any
|
|
// further reads of any kind to succeed from body, nor any
|
|
// subsequent requests on the server connection. See
|
|
// golang.org/issue/12027
|
|
b.sawEOF = false
|
|
b.closed = true
|
|
}
|
|
b.hdr = nil
|
|
} else {
|
|
// If the server declared the Content-Length, our body is a LimitedReader
|
|
// and we need to check whether this EOF arrived early.
|
|
if lr, ok := b.src.(*io.LimitedReader); ok && lr.N > 0 {
|
|
err = io.ErrUnexpectedEOF
|
|
}
|
|
}
|
|
}
|
|
|
|
// If we can return an EOF here along with the read data, do
|
|
// so. This is optional per the io.Reader contract, but doing
|
|
// so helps the HTTP transport code recycle its connection
|
|
// earlier (since it will see this EOF itself), even if the
|
|
// client doesn't do future reads or Close.
|
|
if err == nil && n > 0 {
|
|
if lr, ok := b.src.(*io.LimitedReader); ok && lr.N == 0 {
|
|
err = io.EOF
|
|
b.sawEOF = true
|
|
}
|
|
}
|
|
|
|
if b.sawEOF && b.onHitEOF != nil {
|
|
b.onHitEOF()
|
|
}
|
|
|
|
return n, err
|
|
}
|
|
|
|
var (
|
|
singleCRLF = []byte("\r\n")
|
|
doubleCRLF = []byte("\r\n\r\n")
|
|
)
|
|
|
|
func seeUpcomingDoubleCRLF(r *bufio.Reader) bool {
|
|
for peekSize := 4; ; peekSize++ {
|
|
// This loop stops when Peek returns an error,
|
|
// which it does when r's buffer has been filled.
|
|
buf, err := r.Peek(peekSize)
|
|
if bytes.HasSuffix(buf, doubleCRLF) {
|
|
return true
|
|
}
|
|
if err != nil {
|
|
break
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
var errTrailerEOF = errors.New("http: unexpected EOF reading trailer")
|
|
|
|
func (b *body) readTrailer() error {
|
|
// The common case, since nobody uses trailers.
|
|
buf, err := b.r.Peek(2)
|
|
if bytes.Equal(buf, singleCRLF) {
|
|
b.r.Discard(2)
|
|
return nil
|
|
}
|
|
if len(buf) < 2 {
|
|
return errTrailerEOF
|
|
}
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Make sure there's a header terminator coming up, to prevent
|
|
// a DoS with an unbounded size Trailer. It's not easy to
|
|
// slip in a LimitReader here, as textproto.NewReader requires
|
|
// a concrete *bufio.Reader. Also, we can't get all the way
|
|
// back up to our conn's LimitedReader that *might* be backing
|
|
// this bufio.Reader. Instead, a hack: we iteratively Peek up
|
|
// to the bufio.Reader's max size, looking for a double CRLF.
|
|
// This limits the trailer to the underlying buffer size, typically 4kB.
|
|
if !seeUpcomingDoubleCRLF(b.r) {
|
|
return errors.New("http: suspiciously long trailer after chunked body")
|
|
}
|
|
|
|
hdr, err := textproto.NewReader(b.r).ReadMIMEHeader()
|
|
if err != nil {
|
|
if err == io.EOF {
|
|
return errTrailerEOF
|
|
}
|
|
return err
|
|
}
|
|
switch rr := b.hdr.(type) {
|
|
case *Request:
|
|
mergeSetHeader(&rr.Trailer, Header(hdr))
|
|
case *Response:
|
|
mergeSetHeader(&rr.Trailer, Header(hdr))
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func mergeSetHeader(dst *Header, src Header) {
|
|
if *dst == nil {
|
|
*dst = src
|
|
return
|
|
}
|
|
for k, vv := range src {
|
|
(*dst)[k] = vv
|
|
}
|
|
}
|
|
|
|
// unreadDataSizeLocked returns the number of bytes of unread input.
|
|
// It returns -1 if unknown.
|
|
// b.mu must be held.
|
|
func (b *body) unreadDataSizeLocked() int64 {
|
|
if lr, ok := b.src.(*io.LimitedReader); ok {
|
|
return lr.N
|
|
}
|
|
return -1
|
|
}
|
|
|
|
func (b *body) Close() error {
|
|
b.mu.Lock()
|
|
defer b.mu.Unlock()
|
|
if b.closed {
|
|
return nil
|
|
}
|
|
var err error
|
|
switch {
|
|
case b.sawEOF:
|
|
// Already saw EOF, so no need going to look for it.
|
|
case b.hdr == nil && b.closing:
|
|
// no trailer and closing the connection next.
|
|
// no point in reading to EOF.
|
|
case b.doEarlyClose:
|
|
// Read up to maxPostHandlerReadBytes bytes of the body, looking
|
|
// for EOF (and trailers), so we can re-use this connection.
|
|
if lr, ok := b.src.(*io.LimitedReader); ok && lr.N > maxPostHandlerReadBytes {
|
|
// There was a declared Content-Length, and we have more bytes remaining
|
|
// than our maxPostHandlerReadBytes tolerance. So, give up.
|
|
b.earlyClose = true
|
|
} else {
|
|
var n int64
|
|
// Consume the body, or, which will also lead to us reading
|
|
// the trailer headers after the body, if present.
|
|
n, err = io.CopyN(io.Discard, bodyLocked{b}, maxPostHandlerReadBytes)
|
|
if err == io.EOF {
|
|
err = nil
|
|
}
|
|
if n == maxPostHandlerReadBytes {
|
|
b.earlyClose = true
|
|
}
|
|
}
|
|
default:
|
|
// Fully consume the body, which will also lead to us reading
|
|
// the trailer headers after the body, if present.
|
|
_, err = io.Copy(io.Discard, bodyLocked{b})
|
|
}
|
|
b.closed = true
|
|
return err
|
|
}
|
|
|
|
func (b *body) didEarlyClose() bool {
|
|
b.mu.Lock()
|
|
defer b.mu.Unlock()
|
|
return b.earlyClose
|
|
}
|
|
|
|
// bodyRemains reports whether future Read calls might
|
|
// yield data.
|
|
func (b *body) bodyRemains() bool {
|
|
b.mu.Lock()
|
|
defer b.mu.Unlock()
|
|
return !b.sawEOF
|
|
}
|
|
|
|
func (b *body) registerOnHitEOF(fn func()) {
|
|
b.mu.Lock()
|
|
defer b.mu.Unlock()
|
|
b.onHitEOF = fn
|
|
}
|
|
|
|
// bodyLocked is an io.Reader reading from a *body when its mutex is
|
|
// already held.
|
|
type bodyLocked struct {
|
|
b *body
|
|
}
|
|
|
|
func (bl bodyLocked) Read(p []byte) (n int, err error) {
|
|
if bl.b.closed {
|
|
return 0, ErrBodyReadAfterClose
|
|
}
|
|
return bl.b.readLocked(p)
|
|
}
|
|
|
|
// parseContentLength trims whitespace from s and returns -1 if no value
|
|
// is set, or the value if it's >= 0.
|
|
func parseContentLength(cl string) (int64, error) {
|
|
cl = textproto.TrimString(cl)
|
|
if cl == "" {
|
|
return -1, nil
|
|
}
|
|
n, err := strconv.ParseUint(cl, 10, 63)
|
|
if err != nil {
|
|
return 0, badStringError("bad Content-Length", cl)
|
|
}
|
|
return int64(n), nil
|
|
|
|
}
|
|
|
|
// finishAsyncByteRead finishes reading the 1-byte sniff
|
|
// from the ContentLength==0, Body!=nil case.
|
|
type finishAsyncByteRead struct {
|
|
tw *transferWriter
|
|
}
|
|
|
|
func (fr finishAsyncByteRead) Read(p []byte) (n int, err error) {
|
|
if len(p) == 0 {
|
|
return
|
|
}
|
|
rres := <-fr.tw.ByteReadCh
|
|
n, err = rres.n, rres.err
|
|
if n == 1 {
|
|
p[0] = rres.b
|
|
}
|
|
if err == nil {
|
|
err = io.EOF
|
|
}
|
|
return
|
|
}
|
|
|
|
var nopCloserType = reflect.TypeOf(io.NopCloser(nil))
|
|
|
|
// isKnownInMemoryReader reports whether r is a type known to not
|
|
// block on Read. Its caller uses this as an optional optimization to
|
|
// send fewer TCP packets.
|
|
func isKnownInMemoryReader(r io.Reader) bool {
|
|
switch r.(type) {
|
|
case *bytes.Reader, *bytes.Buffer, *strings.Reader:
|
|
return true
|
|
}
|
|
if reflect.TypeOf(r) == nopCloserType {
|
|
return isKnownInMemoryReader(reflect.ValueOf(r).Field(0).Interface().(io.Reader))
|
|
}
|
|
if r, ok := r.(*readTrackingBody); ok {
|
|
return isKnownInMemoryReader(r.ReadCloser)
|
|
}
|
|
return false
|
|
}
|
|
|
|
// bufioFlushWriter is an io.Writer wrapper that flushes all writes
|
|
// on its wrapped writer if it's a *bufio.Writer.
|
|
type bufioFlushWriter struct{ w io.Writer }
|
|
|
|
func (fw bufioFlushWriter) Write(p []byte) (n int, err error) {
|
|
n, err = fw.w.Write(p)
|
|
if bw, ok := fw.w.(*bufio.Writer); n > 0 && ok {
|
|
ferr := bw.Flush()
|
|
if ferr != nil && err == nil {
|
|
err = ferr
|
|
}
|
|
}
|
|
return
|
|
}
|