mirror of
https://github.com/chrislusf/seaweedfs
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277 lines
7.1 KiB
Go
277 lines
7.1 KiB
Go
package s3api
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// the related code is copied and modified from minio source code
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/*
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* Minio Cloud Storage, (C) 2016 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import (
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"bufio"
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"bytes"
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"errors"
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"github.com/dustin/go-humanize"
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"io"
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"net/http"
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)
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// Streaming AWS Signature Version '4' constants.
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const (
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streamingContentSHA256 = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD"
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)
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const maxLineLength = 4 * humanize.KiByte // assumed <= bufio.defaultBufSize 4KiB
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// lineTooLong is generated as chunk header is bigger than 4KiB.
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var errLineTooLong = errors.New("header line too long")
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// Malformed encoding is generated when chunk header is wrongly formed.
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var errMalformedEncoding = errors.New("malformed chunked encoding")
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// newSignV4ChunkedReader returns a new s3ChunkedReader that translates the data read from r
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// out of HTTP "chunked" format before returning it.
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// The s3ChunkedReader returns io.EOF when the final 0-length chunk is read.
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func newSignV4ChunkedReader(req *http.Request) io.ReadCloser {
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return &s3ChunkedReader{
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reader: bufio.NewReader(req.Body),
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state: readChunkHeader,
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}
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}
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// Represents the overall state that is required for decoding a
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// AWS Signature V4 chunked reader.
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type s3ChunkedReader struct {
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reader *bufio.Reader
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state chunkState
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lastChunk bool
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chunkSignature string
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n uint64 // Unread bytes in chunk
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err error
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}
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// Read chunk reads the chunk token signature portion.
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func (cr *s3ChunkedReader) readS3ChunkHeader() {
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// Read the first chunk line until CRLF.
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var hexChunkSize, hexChunkSignature []byte
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hexChunkSize, hexChunkSignature, cr.err = readChunkLine(cr.reader)
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if cr.err != nil {
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return
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}
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// <hex>;token=value - converts the hex into its uint64 form.
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cr.n, cr.err = parseHexUint(hexChunkSize)
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if cr.err != nil {
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return
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}
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if cr.n == 0 {
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cr.err = io.EOF
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}
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// Save the incoming chunk signature.
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cr.chunkSignature = string(hexChunkSignature)
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}
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type chunkState int
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const (
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readChunkHeader chunkState = iota
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readChunkTrailer
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readChunk
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verifyChunk
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eofChunk
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)
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func (cs chunkState) String() string {
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stateString := ""
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switch cs {
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case readChunkHeader:
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stateString = "readChunkHeader"
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case readChunkTrailer:
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stateString = "readChunkTrailer"
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case readChunk:
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stateString = "readChunk"
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case verifyChunk:
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stateString = "verifyChunk"
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case eofChunk:
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stateString = "eofChunk"
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}
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return stateString
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}
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func (cr *s3ChunkedReader) Close() (err error) {
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return nil
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}
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// Read - implements `io.Reader`, which transparently decodes
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// the incoming AWS Signature V4 streaming signature.
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func (cr *s3ChunkedReader) Read(buf []byte) (n int, err error) {
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for {
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switch cr.state {
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case readChunkHeader:
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cr.readS3ChunkHeader()
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// If we're at the end of a chunk.
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if cr.n == 0 && cr.err == io.EOF {
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cr.state = readChunkTrailer
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cr.lastChunk = true
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continue
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}
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if cr.err != nil {
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return 0, cr.err
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}
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cr.state = readChunk
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case readChunkTrailer:
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cr.err = readCRLF(cr.reader)
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if cr.err != nil {
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return 0, errMalformedEncoding
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}
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cr.state = verifyChunk
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case readChunk:
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// There is no more space left in the request buffer.
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if len(buf) == 0 {
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return n, nil
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}
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rbuf := buf
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// The request buffer is larger than the current chunk size.
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// Read only the current chunk from the underlying reader.
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if uint64(len(rbuf)) > cr.n {
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rbuf = rbuf[:cr.n]
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}
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var n0 int
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n0, cr.err = cr.reader.Read(rbuf)
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if cr.err != nil {
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// We have lesser than chunk size advertised in chunkHeader, this is 'unexpected'.
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if cr.err == io.EOF {
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cr.err = io.ErrUnexpectedEOF
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}
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return 0, cr.err
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}
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// Update the bytes read into request buffer so far.
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n += n0
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buf = buf[n0:]
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// Update bytes to be read of the current chunk before verifying chunk's signature.
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cr.n -= uint64(n0)
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// If we're at the end of a chunk.
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if cr.n == 0 {
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cr.state = readChunkTrailer
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continue
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}
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case verifyChunk:
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if cr.lastChunk {
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cr.state = eofChunk
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} else {
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cr.state = readChunkHeader
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}
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case eofChunk:
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return n, io.EOF
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}
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}
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}
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// readCRLF - check if reader only has '\r\n' CRLF character.
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// returns malformed encoding if it doesn't.
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func readCRLF(reader io.Reader) error {
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buf := make([]byte, 2)
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_, err := io.ReadFull(reader, buf[:2])
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if err != nil {
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return err
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}
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if buf[0] != '\r' || buf[1] != '\n' {
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return errMalformedEncoding
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}
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return nil
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}
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// Read a line of bytes (up to \n) from b.
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// Give up if the line exceeds maxLineLength.
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// The returned bytes are owned by the bufio.Reader
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// so they are only valid until the next bufio read.
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func readChunkLine(b *bufio.Reader) ([]byte, []byte, error) {
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buf, err := b.ReadSlice('\n')
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if err != nil {
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// We always know when EOF is coming.
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// If the caller asked for a line, there should be a line.
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if err == io.EOF {
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err = io.ErrUnexpectedEOF
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} else if err == bufio.ErrBufferFull {
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err = errLineTooLong
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}
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return nil, nil, err
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}
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if len(buf) >= maxLineLength {
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return nil, nil, errLineTooLong
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}
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// Parse s3 specific chunk extension and fetch the values.
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hexChunkSize, hexChunkSignature := parseS3ChunkExtension(buf)
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return hexChunkSize, hexChunkSignature, nil
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}
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// trimTrailingWhitespace - trim trailing white space.
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func trimTrailingWhitespace(b []byte) []byte {
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for len(b) > 0 && isASCIISpace(b[len(b)-1]) {
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b = b[:len(b)-1]
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}
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return b
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}
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// isASCIISpace - is ascii space?
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func isASCIISpace(b byte) bool {
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return b == ' ' || b == '\t' || b == '\n' || b == '\r'
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}
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// Constant s3 chunk encoding signature.
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const s3ChunkSignatureStr = ";chunk-signature="
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// parses3ChunkExtension removes any s3 specific chunk-extension from buf.
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// For example,
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// "10000;chunk-signature=..." => "10000", "chunk-signature=..."
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func parseS3ChunkExtension(buf []byte) ([]byte, []byte) {
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buf = trimTrailingWhitespace(buf)
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semi := bytes.Index(buf, []byte(s3ChunkSignatureStr))
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// Chunk signature not found, return the whole buffer.
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if semi == -1 {
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return buf, nil
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}
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return buf[:semi], parseChunkSignature(buf[semi:])
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}
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// parseChunkSignature - parse chunk signature.
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func parseChunkSignature(chunk []byte) []byte {
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chunkSplits := bytes.SplitN(chunk, []byte(s3ChunkSignatureStr), 2)
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return chunkSplits[1]
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}
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// parse hex to uint64.
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func parseHexUint(v []byte) (n uint64, err error) {
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for i, b := range v {
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switch {
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case '0' <= b && b <= '9':
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b = b - '0'
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case 'a' <= b && b <= 'f':
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b = b - 'a' + 10
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case 'A' <= b && b <= 'F':
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b = b - 'A' + 10
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default:
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return 0, errors.New("invalid byte in chunk length")
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}
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if i == 16 {
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return 0, errors.New("http chunk length too large")
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}
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n <<= 4
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n |= uint64(b)
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}
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return
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}
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