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gitea/vendor/github.com/minio/minio-go/v7/pkg/signer/request-signature-streaming.go

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Go

/*
* MinIO Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 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 signer
import (
"bytes"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"net/http"
"strconv"
"strings"
"time"
)
// Reference for constants used below -
// http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-streaming.html#example-signature-calculations-streaming
const (
streamingSignAlgorithm = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD"
streamingPayloadHdr = "AWS4-HMAC-SHA256-PAYLOAD"
emptySHA256 = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
payloadChunkSize = 64 * 1024
chunkSigConstLen = 17 // ";chunk-signature="
signatureStrLen = 64 // e.g. "f2ca1bb6c7e907d06dafe4687e579fce76b37e4e93b7605022da52e6ccc26fd2"
crlfLen = 2 // CRLF
)
// Request headers to be ignored while calculating seed signature for
// a request.
var ignoredStreamingHeaders = map[string]bool{
"Authorization": true,
"User-Agent": true,
"Content-Type": true,
}
// getSignedChunkLength - calculates the length of chunk metadata
func getSignedChunkLength(chunkDataSize int64) int64 {
return int64(len(fmt.Sprintf("%x", chunkDataSize))) +
chunkSigConstLen +
signatureStrLen +
crlfLen +
chunkDataSize +
crlfLen
}
// getStreamLength - calculates the length of the overall stream (data + metadata)
func getStreamLength(dataLen, chunkSize int64) int64 {
if dataLen <= 0 {
return 0
}
chunksCount := int64(dataLen / chunkSize)
remainingBytes := int64(dataLen % chunkSize)
streamLen := int64(0)
streamLen += chunksCount * getSignedChunkLength(chunkSize)
if remainingBytes > 0 {
streamLen += getSignedChunkLength(remainingBytes)
}
streamLen += getSignedChunkLength(0)
return streamLen
}
// buildChunkStringToSign - returns the string to sign given chunk data
// and previous signature.
func buildChunkStringToSign(t time.Time, region, previousSig string, chunkData []byte) string {
stringToSignParts := []string{
streamingPayloadHdr,
t.Format(iso8601DateFormat),
getScope(region, t, ServiceTypeS3),
previousSig,
emptySHA256,
hex.EncodeToString(sum256(chunkData)),
}
return strings.Join(stringToSignParts, "\n")
}
// prepareStreamingRequest - prepares a request with appropriate
// headers before computing the seed signature.
func prepareStreamingRequest(req *http.Request, sessionToken string, dataLen int64, timestamp time.Time) {
// Set x-amz-content-sha256 header.
req.Header.Set("X-Amz-Content-Sha256", streamingSignAlgorithm)
if sessionToken != "" {
req.Header.Set("X-Amz-Security-Token", sessionToken)
}
req.Header.Set("X-Amz-Date", timestamp.Format(iso8601DateFormat))
// Set content length with streaming signature for each chunk included.
req.ContentLength = getStreamLength(dataLen, int64(payloadChunkSize))
req.Header.Set("x-amz-decoded-content-length", strconv.FormatInt(dataLen, 10))
}
// buildChunkHeader - returns the chunk header.
// e.g string(IntHexBase(chunk-size)) + ";chunk-signature=" + signature + \r\n + chunk-data + \r\n
func buildChunkHeader(chunkLen int64, signature string) []byte {
return []byte(strconv.FormatInt(chunkLen, 16) + ";chunk-signature=" + signature + "\r\n")
}
// buildChunkSignature - returns chunk signature for a given chunk and previous signature.
func buildChunkSignature(chunkData []byte, reqTime time.Time, region,
previousSignature, secretAccessKey string) string {
chunkStringToSign := buildChunkStringToSign(reqTime, region,
previousSignature, chunkData)
signingKey := getSigningKey(secretAccessKey, region, reqTime, ServiceTypeS3)
return getSignature(signingKey, chunkStringToSign)
}
// getSeedSignature - returns the seed signature for a given request.
func (s *StreamingReader) setSeedSignature(req *http.Request) {
// Get canonical request
canonicalRequest := getCanonicalRequest(*req, ignoredStreamingHeaders, getHashedPayload(*req))
// Get string to sign from canonical request.
stringToSign := getStringToSignV4(s.reqTime, s.region, canonicalRequest, ServiceTypeS3)
signingKey := getSigningKey(s.secretAccessKey, s.region, s.reqTime, ServiceTypeS3)
// Calculate signature.
s.seedSignature = getSignature(signingKey, stringToSign)
}
// StreamingReader implements chunked upload signature as a reader on
// top of req.Body's ReaderCloser chunk header;data;... repeat
type StreamingReader struct {
accessKeyID string
secretAccessKey string
sessionToken string
region string
prevSignature string
seedSignature string
contentLen int64 // Content-Length from req header
baseReadCloser io.ReadCloser // underlying io.Reader
bytesRead int64 // bytes read from underlying io.Reader
buf bytes.Buffer // holds signed chunk
chunkBuf []byte // holds raw data read from req Body
chunkBufLen int // no. of bytes read so far into chunkBuf
done bool // done reading the underlying reader to EOF
reqTime time.Time
chunkNum int
totalChunks int
lastChunkSize int
}
// signChunk - signs a chunk read from s.baseReader of chunkLen size.
func (s *StreamingReader) signChunk(chunkLen int) {
// Compute chunk signature for next header
signature := buildChunkSignature(s.chunkBuf[:chunkLen], s.reqTime,
s.region, s.prevSignature, s.secretAccessKey)
// For next chunk signature computation
s.prevSignature = signature
// Write chunk header into streaming buffer
chunkHdr := buildChunkHeader(int64(chunkLen), signature)
s.buf.Write(chunkHdr)
// Write chunk data into streaming buffer
s.buf.Write(s.chunkBuf[:chunkLen])
// Write the chunk trailer.
s.buf.Write([]byte("\r\n"))
// Reset chunkBufLen for next chunk read.
s.chunkBufLen = 0
s.chunkNum++
}
// setStreamingAuthHeader - builds and sets authorization header value
// for streaming signature.
func (s *StreamingReader) setStreamingAuthHeader(req *http.Request) {
credential := GetCredential(s.accessKeyID, s.region, s.reqTime, ServiceTypeS3)
authParts := []string{
signV4Algorithm + " Credential=" + credential,
"SignedHeaders=" + getSignedHeaders(*req, ignoredStreamingHeaders),
"Signature=" + s.seedSignature,
}
// Set authorization header.
auth := strings.Join(authParts, ",")
req.Header.Set("Authorization", auth)
}
// StreamingSignV4 - provides chunked upload signatureV4 support by
// implementing io.Reader.
func StreamingSignV4(req *http.Request, accessKeyID, secretAccessKey, sessionToken,
region string, dataLen int64, reqTime time.Time) *http.Request {
// Set headers needed for streaming signature.
prepareStreamingRequest(req, sessionToken, dataLen, reqTime)
if req.Body == nil {
req.Body = ioutil.NopCloser(bytes.NewReader([]byte("")))
}
stReader := &StreamingReader{
baseReadCloser: req.Body,
accessKeyID: accessKeyID,
secretAccessKey: secretAccessKey,
sessionToken: sessionToken,
region: region,
reqTime: reqTime,
chunkBuf: make([]byte, payloadChunkSize),
contentLen: dataLen,
chunkNum: 1,
totalChunks: int((dataLen+payloadChunkSize-1)/payloadChunkSize) + 1,
lastChunkSize: int(dataLen % payloadChunkSize),
}
// Add the request headers required for chunk upload signing.
// Compute the seed signature.
stReader.setSeedSignature(req)
// Set the authorization header with the seed signature.
stReader.setStreamingAuthHeader(req)
// Set seed signature as prevSignature for subsequent
// streaming signing process.
stReader.prevSignature = stReader.seedSignature
req.Body = stReader
return req
}
// Read - this method performs chunk upload signature providing a
// io.Reader interface.
func (s *StreamingReader) Read(buf []byte) (int, error) {
switch {
// After the last chunk is read from underlying reader, we
// never re-fill s.buf.
case s.done:
// s.buf will be (re-)filled with next chunk when has lesser
// bytes than asked for.
case s.buf.Len() < len(buf):
s.chunkBufLen = 0
for {
n1, err := s.baseReadCloser.Read(s.chunkBuf[s.chunkBufLen:])
// Usually we validate `err` first, but in this case
// we are validating n > 0 for the following reasons.
//
// 1. n > 0, err is one of io.EOF, nil (near end of stream)
// A Reader returning a non-zero number of bytes at the end
// of the input stream may return either err == EOF or err == nil
//
// 2. n == 0, err is io.EOF (actual end of stream)
//
// Callers should always process the n > 0 bytes returned
// before considering the error err.
if n1 > 0 {
s.chunkBufLen += n1
s.bytesRead += int64(n1)
if s.chunkBufLen == payloadChunkSize ||
(s.chunkNum == s.totalChunks-1 &&
s.chunkBufLen == s.lastChunkSize) {
// Sign the chunk and write it to s.buf.
s.signChunk(s.chunkBufLen)
break
}
}
if err != nil {
if err == io.EOF {
// No more data left in baseReader - last chunk.
// Done reading the last chunk from baseReader.
s.done = true
// bytes read from baseReader different than
// content length provided.
if s.bytesRead != s.contentLen {
return 0, fmt.Errorf("http: ContentLength=%d with Body length %d", s.contentLen, s.bytesRead)
}
// Sign the chunk and write it to s.buf.
s.signChunk(0)
break
}
return 0, err
}
}
}
return s.buf.Read(buf)
}
// Close - this method makes underlying io.ReadCloser's Close method available.
func (s *StreamingReader) Close() error {
return s.baseReadCloser.Close()
}