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crypt: Implement RangeOption #1825
This commit is contained in:
Nick Craig-Wood
parent
451cd6d971
commit
c929de9dc4
@ -14,6 +14,7 @@ import (
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"unicode/utf8"
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"github.com/ncw/rclone/backend/crypt/pkcs7"
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"github.com/ncw/rclone/fs"
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"github.com/ncw/rclone/fs/accounting"
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"github.com/pkg/errors"
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@ -64,10 +65,11 @@ type ReadSeekCloser interface {
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io.Reader
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io.Seeker
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io.Closer
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fs.RangeSeeker
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}
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// OpenAtOffset opens the file handle at the offset given
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type OpenAtOffset func(offset int64) (io.ReadCloser, error)
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// OpenRangeSeek opens the file handle at the offset with the limit given
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type OpenRangeSeek func(offset, limit int64) (io.ReadCloser, error)
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// Cipher is used to swap out the encryption implementations
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type Cipher interface {
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@ -84,7 +86,7 @@ type Cipher interface {
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// DecryptData
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DecryptData(io.ReadCloser) (io.ReadCloser, error)
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// DecryptDataSeek decrypt at a given position
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DecryptDataSeek(open OpenAtOffset, offset int64) (ReadSeekCloser, error)
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DecryptDataSeek(open OpenRangeSeek, offset, limit int64) (ReadSeekCloser, error)
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// EncryptedSize calculates the size of the data when encrypted
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EncryptedSize(int64) int64
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// DecryptedSize calculates the size of the data when decrypted
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@ -712,7 +714,8 @@ type decrypter struct {
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bufIndex int
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bufSize int
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err error
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open OpenAtOffset
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limit int64 // limit of bytes to read, -1 for unlimited
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open OpenRangeSeek
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}
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// newDecrypter creates a new file handle decrypting on the fly
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@ -722,6 +725,7 @@ func (c *cipher) newDecrypter(rc io.ReadCloser) (*decrypter, error) {
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c: c,
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buf: c.getBlock(),
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readBuf: c.getBlock(),
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limit: -1,
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}
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// Read file header (magic + nonce)
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readBuf := fh.readBuf[:fileHeaderSize]
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@ -743,9 +747,24 @@ func (c *cipher) newDecrypter(rc io.ReadCloser) (*decrypter, error) {
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}
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// newDecrypterSeek creates a new file handle decrypting on the fly
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func (c *cipher) newDecrypterSeek(open OpenAtOffset, offset int64) (fh *decrypter, err error) {
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func (c *cipher) newDecrypterSeek(open OpenRangeSeek, offset, limit int64) (fh *decrypter, err error) {
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var rc io.ReadCloser
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doRangeSeek := false
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setLimit := false
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// Open initially with no seek
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rc, err := open(0)
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if offset == 0 && limit < 0 {
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// If no offset or limit then open whole file
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rc, err = open(0, -1)
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} else if offset == 0 {
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// If no offset open the header + limit worth of the file
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_, underlyingLimit, _, _ := calculateUnderlying(offset, limit)
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rc, err = open(0, int64(fileHeaderSize)+underlyingLimit)
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setLimit = true
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} else {
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// Otherwise just read the header to start with
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rc, err = open(0, int64(fileHeaderSize))
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doRangeSeek = true
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}
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if err != nil {
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return nil, err
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}
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@ -754,14 +773,17 @@ func (c *cipher) newDecrypterSeek(open OpenAtOffset, offset int64) (fh *decrypte
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if err != nil {
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return nil, err
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}
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fh.open = open // will be called by fh.Seek
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if offset != 0 {
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_, err = fh.Seek(offset, 0)
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fh.open = open // will be called by fh.RangeSeek
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if doRangeSeek {
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_, err = fh.RangeSeek(offset, 0, limit)
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if err != nil {
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_ = fh.Close()
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return nil, err
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}
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}
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if setLimit {
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fh.limit = limit
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}
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return fh, nil
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}
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@ -814,13 +836,66 @@ func (fh *decrypter) Read(p []byte) (n int, err error) {
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return 0, fh.finish(err)
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}
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}
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n = copy(p, fh.buf[fh.bufIndex:fh.bufSize])
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toCopy := fh.bufSize - fh.bufIndex
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if fh.limit >= 0 && fh.limit < int64(toCopy) {
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toCopy = int(fh.limit)
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}
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n = copy(p, fh.buf[fh.bufIndex:fh.bufIndex+toCopy])
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fh.bufIndex += n
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if fh.limit >= 0 {
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fh.limit -= int64(n)
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if fh.limit == 0 {
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return n, fh.finish(io.EOF)
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}
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}
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return n, nil
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}
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// Seek as per io.Seeker
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func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
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// calculateUnderlying converts an (offset, limit) in a crypted file
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// into an (underlyingOffset, underlyingLimit) for the underlying
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// file.
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//
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// It also returns number of bytes to discard after reading the first
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// block and number of blocks this is from the start so the nonce can
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// be incremented.
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func calculateUnderlying(offset, limit int64) (underlyingOffset, underlyingLimit, discard, blocks int64) {
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// blocks we need to seek, plus bytes we need to discard
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blocks, discard = offset/blockDataSize, offset%blockDataSize
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// Offset in underlying stream we need to seek
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underlyingOffset = int64(fileHeaderSize) + blocks*(blockHeaderSize+blockDataSize)
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// work out how many blocks we need to read
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underlyingLimit = int64(-1)
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if limit >= 0 {
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// bytes to read beyond the first block
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bytesToRead := limit - (blockDataSize - discard)
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// Read the first block
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blocksToRead := int64(1)
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if bytesToRead > 0 {
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// Blocks that need to be read plus left over blocks
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extraBlocksToRead, endBytes := bytesToRead/blockDataSize, bytesToRead%blockDataSize
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if endBytes != 0 {
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// If left over bytes must read another block
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extraBlocksToRead++
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}
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blocksToRead += extraBlocksToRead
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}
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// Must read a whole number of blocks
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underlyingLimit = blocksToRead * (blockHeaderSize + blockDataSize)
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}
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return
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}
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// RangeSeek behaves like a call to Seek(offset int64, whence
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// int) with the output wrapped in an io.LimitedReader
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// limiting the total length to limit.
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//
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// RangeSeek with a limit of < 0 is equivalent to a regular Seek.
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func (fh *decrypter) RangeSeek(offset int64, whence int, limit int64) (int64, error) {
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fh.mu.Lock()
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defer fh.mu.Unlock()
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@ -838,20 +913,16 @@ func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
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return 0, fh.err
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}
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// blocks we need to seek, plus bytes we need to discard
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blocks, discard := offset/blockDataSize, offset%blockDataSize
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// Offset in underlying stream we need to seek
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underlyingOffset := int64(fileHeaderSize) + blocks*(blockHeaderSize+blockDataSize)
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underlyingOffset, underlyingLimit, discard, blocks := calculateUnderlying(offset, limit)
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// Move the nonce on the correct number of blocks from the start
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fh.nonce = fh.initialNonce
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fh.nonce.add(uint64(blocks))
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// Can we seek underlying stream directly?
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if do, ok := fh.rc.(io.Seeker); ok {
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if do, ok := fh.rc.(fs.RangeSeeker); ok {
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// Seek underlying stream directly
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_, err := do.Seek(underlyingOffset, 0)
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_, err := do.RangeSeek(underlyingOffset, 0, underlyingLimit)
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if err != nil {
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return 0, fh.finish(err)
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}
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@ -861,9 +932,9 @@ func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
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fh.rc = nil
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// Re-open the underlying object with the offset given
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rc, err := fh.open(underlyingOffset)
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rc, err := fh.open(underlyingOffset, underlyingLimit)
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if err != nil {
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return 0, fh.finish(errors.Wrap(err, "couldn't reopen file with offset"))
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return 0, fh.finish(errors.Wrap(err, "couldn't reopen file with offset and limit"))
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}
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// Set the file handle
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@ -882,9 +953,17 @@ func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
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}
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fh.bufIndex = int(discard)
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// Set the limit
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fh.limit = limit
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return offset, nil
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}
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// Seek implements the io.Seeker interface
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func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
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return fh.RangeSeek(offset, whence, -1)
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}
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// finish sets the final error and tidies up
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func (fh *decrypter) finish(err error) error {
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if fh.err != nil {
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@ -956,8 +1035,8 @@ func (c *cipher) DecryptData(rc io.ReadCloser) (io.ReadCloser, error) {
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// The open function must return a ReadCloser opened to the offset supplied
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//
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// You must use this form of DecryptData if you might want to Seek the file handle
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func (c *cipher) DecryptDataSeek(open OpenAtOffset, offset int64) (ReadSeekCloser, error) {
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out, err := c.newDecrypterSeek(open, offset)
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func (c *cipher) DecryptDataSeek(open OpenRangeSeek, offset, limit int64) (ReadSeekCloser, error) {
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out, err := c.newDecrypterSeek(open, offset, limit)
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if err != nil {
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return nil, err
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}
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@ -994,7 +1073,9 @@ func (c *cipher) DecryptedSize(size int64) (int64, error) {
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// check interfaces
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var (
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_ Cipher = (*cipher)(nil)
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_ io.ReadCloser = (*decrypter)(nil)
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_ io.Reader = (*encrypter)(nil)
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_ Cipher = (*cipher)(nil)
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_ io.ReadCloser = (*decrypter)(nil)
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_ io.Seeker = (*decrypter)(nil)
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_ fs.RangeSeeker = (*decrypter)(nil)
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_ io.Reader = (*encrypter)(nil)
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)
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@ -935,7 +935,7 @@ func TestNewDecrypterErrUnexpectedEOF(t *testing.T) {
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assert.Equal(t, int64(16), n)
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}
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func TestNewDecrypterSeek(t *testing.T) {
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func TestNewDecrypterSeekLimit(t *testing.T) {
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c, err := newCipher(NameEncryptionStandard, "", "", true)
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assert.NoError(t, err)
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c.cryptoRand = &zeroes{} // nodge the crypto rand generator
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@ -956,42 +956,188 @@ func TestNewDecrypterSeek(t *testing.T) {
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127, 128, 129, 255, 256, 257, 511, 512, 513, 1023, 1024, 1025, 2047, 2048, 2049,
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4095, 4096, 4097, 8191, 8192, 8193, 16383, 16384, 16385, 32767, 32768, 32769,
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65535, 65536, 65537, 131071, 131072, 131073, dataSize - 1, dataSize}
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limits := []int{-1, 0, 1, 65535, 65536, 65537, 131071, 131072, 131073}
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// Open stream with a seek of underlyingOffset
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open := func(underlyingOffset int64) (io.ReadCloser, error) {
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return ioutil.NopCloser(bytes.NewBuffer(ciphertext[int(underlyingOffset):])), nil
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var reader io.ReadCloser
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open := func(underlyingOffset, underlyingLimit int64) (io.ReadCloser, error) {
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end := len(ciphertext)
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if underlyingLimit >= 0 {
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end = int(underlyingOffset + underlyingLimit)
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if end > len(ciphertext) {
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end = len(ciphertext)
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}
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}
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reader = ioutil.NopCloser(bytes.NewBuffer(ciphertext[int(underlyingOffset):end]))
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return reader, nil
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}
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inBlock := make([]byte, 1024)
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inBlock := make([]byte, dataSize)
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// Check the seek worked by reading a block and checking it
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// against what it should be
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check := func(rc ReadSeekCloser, offset int) {
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check := func(rc io.Reader, offset, limit int) {
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n, err := io.ReadFull(rc, inBlock)
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if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
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require.NoError(t, err)
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}
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seekedDecrypted := inBlock[:n]
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require.Equal(t, plaintext[offset:offset+n], seekedDecrypted)
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what := fmt.Sprintf("offset = %d, limit = %d", offset, limit)
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if limit >= 0 {
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assert.Equal(t, limit, n, what)
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}
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require.Equal(t, plaintext[offset:offset+n], seekedDecrypted, what)
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// We should have completely emptied the reader at this point
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n, err = reader.Read(inBlock)
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assert.Equal(t, io.EOF, err)
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assert.Equal(t, 0, n)
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}
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// Now try decoding it with a open/seek
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for _, offset := range trials {
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rc, err := c.DecryptDataSeek(open, int64(offset))
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assert.NoError(t, err)
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for _, limit := range limits {
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if offset+limit > len(plaintext) {
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continue
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}
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rc, err := c.DecryptDataSeek(open, int64(offset), int64(limit))
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assert.NoError(t, err)
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check(rc, offset)
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check(rc, offset, limit)
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}
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}
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// Now try decoding it with a single open and lots of seeks
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rc, err := c.DecryptDataSeek(open, 0)
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// Try decoding it with a single open and lots of seeks
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fh, err := c.DecryptDataSeek(open, 0, -1)
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assert.NoError(t, err)
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for _, offset := range trials {
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_, err := rc.Seek(int64(offset), 0)
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assert.NoError(t, err)
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for _, limit := range limits {
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if offset+limit > len(plaintext) {
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continue
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}
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_, err := fh.RangeSeek(int64(offset), 0, int64(limit))
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assert.NoError(t, err)
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check(rc, offset)
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check(fh, offset, limit)
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}
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}
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// Do some checks on the open callback
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for _, test := range []struct {
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offset, limit int64
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wantOffset, wantLimit int64
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}{
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// unlimited
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{0, -1, int64(fileHeaderSize), -1},
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{1, -1, int64(fileHeaderSize), -1},
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{blockDataSize - 1, -1, int64(fileHeaderSize), -1},
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{blockDataSize, -1, int64(fileHeaderSize) + blockSize, -1},
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{blockDataSize + 1, -1, int64(fileHeaderSize) + blockSize, -1},
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// limit=1
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{0, 1, int64(fileHeaderSize), blockSize},
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{1, 1, int64(fileHeaderSize), blockSize},
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{blockDataSize - 1, 1, int64(fileHeaderSize), blockSize},
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{blockDataSize, 1, int64(fileHeaderSize) + blockSize, blockSize},
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{blockDataSize + 1, 1, int64(fileHeaderSize) + blockSize, blockSize},
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// limit=100
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{0, 100, int64(fileHeaderSize), blockSize},
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{1, 100, int64(fileHeaderSize), blockSize},
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{blockDataSize - 1, 100, int64(fileHeaderSize), 2 * blockSize},
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{blockDataSize, 100, int64(fileHeaderSize) + blockSize, blockSize},
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{blockDataSize + 1, 100, int64(fileHeaderSize) + blockSize, blockSize},
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// limit=blockDataSize-1
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{0, blockDataSize - 1, int64(fileHeaderSize), blockSize},
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{1, blockDataSize - 1, int64(fileHeaderSize), blockSize},
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{blockDataSize - 1, blockDataSize - 1, int64(fileHeaderSize), 2 * blockSize},
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{blockDataSize, blockDataSize - 1, int64(fileHeaderSize) + blockSize, blockSize},
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{blockDataSize + 1, blockDataSize - 1, int64(fileHeaderSize) + blockSize, blockSize},
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// limit=blockDataSize
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{0, blockDataSize, int64(fileHeaderSize), blockSize},
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{1, blockDataSize, int64(fileHeaderSize), 2 * blockSize},
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{blockDataSize - 1, blockDataSize, int64(fileHeaderSize), 2 * blockSize},
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{blockDataSize, blockDataSize, int64(fileHeaderSize) + blockSize, blockSize},
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{blockDataSize + 1, blockDataSize, int64(fileHeaderSize) + blockSize, 2 * blockSize},
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// limit=blockDataSize+1
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{0, blockDataSize + 1, int64(fileHeaderSize), 2 * blockSize},
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{1, blockDataSize + 1, int64(fileHeaderSize), 2 * blockSize},
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{blockDataSize - 1, blockDataSize + 1, int64(fileHeaderSize), 2 * blockSize},
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{blockDataSize, blockDataSize + 1, int64(fileHeaderSize) + blockSize, 2 * blockSize},
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{blockDataSize + 1, blockDataSize + 1, int64(fileHeaderSize) + blockSize, 2 * blockSize},
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} {
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what := fmt.Sprintf("offset = %d, limit = %d", test.offset, test.limit)
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callCount := 0
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testOpen := func(underlyingOffset, underlyingLimit int64) (io.ReadCloser, error) {
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switch callCount {
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case 0:
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assert.Equal(t, int64(0), underlyingOffset, what)
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assert.Equal(t, int64(-1), underlyingLimit, what)
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case 1:
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assert.Equal(t, test.wantOffset, underlyingOffset, what)
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assert.Equal(t, test.wantLimit, underlyingLimit, what)
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default:
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t.Errorf("Too many calls %d for %s", callCount+1, what)
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}
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callCount++
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return open(underlyingOffset, underlyingLimit)
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}
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fh, err := c.DecryptDataSeek(testOpen, 0, -1)
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assert.NoError(t, err)
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gotOffset, err := fh.RangeSeek(test.offset, 0, test.limit)
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assert.NoError(t, err)
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assert.Equal(t, gotOffset, test.offset)
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}
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}
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func TestDecrypterCalculateUnderlying(t *testing.T) {
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for _, test := range []struct {
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offset, limit int64
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wantOffset, wantLimit int64
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wantDiscard, wantBlocks int64
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}{
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// unlimited
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{0, -1, int64(fileHeaderSize), -1, 0, 0},
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{1, -1, int64(fileHeaderSize), -1, 1, 0},
|
||||
{blockDataSize - 1, -1, int64(fileHeaderSize), -1, blockDataSize - 1, 0},
|
||||
{blockDataSize, -1, int64(fileHeaderSize) + blockSize, -1, 0, 1},
|
||||
{blockDataSize + 1, -1, int64(fileHeaderSize) + blockSize, -1, 1, 1},
|
||||
// limit=1
|
||||
{0, 1, int64(fileHeaderSize), blockSize, 0, 0},
|
||||
{1, 1, int64(fileHeaderSize), blockSize, 1, 0},
|
||||
{blockDataSize - 1, 1, int64(fileHeaderSize), blockSize, blockDataSize - 1, 0},
|
||||
{blockDataSize, 1, int64(fileHeaderSize) + blockSize, blockSize, 0, 1},
|
||||
{blockDataSize + 1, 1, int64(fileHeaderSize) + blockSize, blockSize, 1, 1},
|
||||
// limit=100
|
||||
{0, 100, int64(fileHeaderSize), blockSize, 0, 0},
|
||||
{1, 100, int64(fileHeaderSize), blockSize, 1, 0},
|
||||
{blockDataSize - 1, 100, int64(fileHeaderSize), 2 * blockSize, blockDataSize - 1, 0},
|
||||
{blockDataSize, 100, int64(fileHeaderSize) + blockSize, blockSize, 0, 1},
|
||||
{blockDataSize + 1, 100, int64(fileHeaderSize) + blockSize, blockSize, 1, 1},
|
||||
// limit=blockDataSize-1
|
||||
{0, blockDataSize - 1, int64(fileHeaderSize), blockSize, 0, 0},
|
||||
{1, blockDataSize - 1, int64(fileHeaderSize), blockSize, 1, 0},
|
||||
{blockDataSize - 1, blockDataSize - 1, int64(fileHeaderSize), 2 * blockSize, blockDataSize - 1, 0},
|
||||
{blockDataSize, blockDataSize - 1, int64(fileHeaderSize) + blockSize, blockSize, 0, 1},
|
||||
{blockDataSize + 1, blockDataSize - 1, int64(fileHeaderSize) + blockSize, blockSize, 1, 1},
|
||||
// limit=blockDataSize
|
||||
{0, blockDataSize, int64(fileHeaderSize), blockSize, 0, 0},
|
||||
{1, blockDataSize, int64(fileHeaderSize), 2 * blockSize, 1, 0},
|
||||
{blockDataSize - 1, blockDataSize, int64(fileHeaderSize), 2 * blockSize, blockDataSize - 1, 0},
|
||||
{blockDataSize, blockDataSize, int64(fileHeaderSize) + blockSize, blockSize, 0, 1},
|
||||
{blockDataSize + 1, blockDataSize, int64(fileHeaderSize) + blockSize, 2 * blockSize, 1, 1},
|
||||
// limit=blockDataSize+1
|
||||
{0, blockDataSize + 1, int64(fileHeaderSize), 2 * blockSize, 0, 0},
|
||||
{1, blockDataSize + 1, int64(fileHeaderSize), 2 * blockSize, 1, 0},
|
||||
{blockDataSize - 1, blockDataSize + 1, int64(fileHeaderSize), 2 * blockSize, blockDataSize - 1, 0},
|
||||
{blockDataSize, blockDataSize + 1, int64(fileHeaderSize) + blockSize, 2 * blockSize, 0, 1},
|
||||
{blockDataSize + 1, blockDataSize + 1, int64(fileHeaderSize) + blockSize, 2 * blockSize, 1, 1},
|
||||
} {
|
||||
what := fmt.Sprintf("offset = %d, limit = %d", test.offset, test.limit)
|
||||
underlyingOffset, underlyingLimit, discard, blocks := calculateUnderlying(test.offset, test.limit)
|
||||
assert.Equal(t, test.wantOffset, underlyingOffset, what)
|
||||
assert.Equal(t, test.wantLimit, underlyingLimit, what)
|
||||
assert.Equal(t, test.wantDiscard, discard, what)
|
||||
assert.Equal(t, test.wantBlocks, blocks, what)
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
@ -573,29 +573,39 @@ func (o *Object) UnWrap() fs.Object {
|
||||
|
||||
// Open opens the file for read. Call Close() on the returned io.ReadCloser
|
||||
func (o *Object) Open(options ...fs.OpenOption) (rc io.ReadCloser, err error) {
|
||||
var offset int64
|
||||
var openOptions []fs.OpenOption
|
||||
var offset, limit int64 = 0, -1
|
||||
for _, option := range options {
|
||||
switch x := option.(type) {
|
||||
case *fs.SeekOption:
|
||||
offset = x.Offset
|
||||
case *fs.RangeOption:
|
||||
offset, limit = x.Decode(o.Size())
|
||||
default:
|
||||
if option.Mandatory() {
|
||||
fs.Logf(o, "Unsupported mandatory option: %v", option)
|
||||
}
|
||||
// pass on Options to underlying open if appropriate
|
||||
openOptions = append(openOptions, option)
|
||||
}
|
||||
}
|
||||
rc, err = o.f.cipher.DecryptDataSeek(func(underlyingOffset int64) (io.ReadCloser, error) {
|
||||
if underlyingOffset == 0 {
|
||||
rc, err = o.f.cipher.DecryptDataSeek(func(underlyingOffset, underlyingLimit int64) (io.ReadCloser, error) {
|
||||
if underlyingOffset == 0 && underlyingLimit < 0 {
|
||||
// Open with no seek
|
||||
return o.Object.Open()
|
||||
return o.Object.Open(openOptions...)
|
||||
}
|
||||
// Open stream with a seek of underlyingOffset
|
||||
return o.Object.Open(&fs.SeekOption{Offset: underlyingOffset})
|
||||
}, offset)
|
||||
// Open stream with a range of underlyingOffset, underlyingLimit
|
||||
end := int64(-1)
|
||||
if underlyingLimit >= 0 {
|
||||
end = underlyingOffset + underlyingLimit - 1
|
||||
if end >= o.Object.Size() {
|
||||
end = -1
|
||||
}
|
||||
}
|
||||
newOpenOptions := append(openOptions, &fs.RangeOption{Start: underlyingOffset, End: end})
|
||||
return o.Object.Open(newOpenOptions...)
|
||||
}, offset, limit)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return rc, err
|
||||
return rc, nil
|
||||
}
|
||||
|
||||
// Update in to the object with the modTime given of the given size
|
||||
|
||||
Loading…
Reference in New Issue
Block a user