b23e21f61f
Discovered by xfstests generic/564 .
Failure was:
generic/564 - output mismatch (see /opt/fuse-xfstests/results//generic/564.out.bad)
--- tests/generic/564.out 2021-05-08 21:11:05.307395966 +0200
+++ /opt/fuse-xfstests/results//generic/564.out.bad 2021-05-19 19:01:16.912888879 +0200
@@ -31,7 +31,7 @@
source range beyond 8TiB returns 0
destination range beyond 8TiB returns EFBIG
-copy_range: File too large
+copy_range: Function not implemented
458 lines
14 KiB
Go
458 lines
14 KiB
Go
package fusefrontend
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// FUSE operations on file handles
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import (
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"bytes"
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"context"
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"encoding/hex"
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"fmt"
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"io"
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"log"
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"math"
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"os"
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"sync"
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"syscall"
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"github.com/hanwen/go-fuse/v2/fs"
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"github.com/hanwen/go-fuse/v2/fuse"
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"github.com/rfjakob/gocryptfs/internal/contentenc"
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"github.com/rfjakob/gocryptfs/internal/inomap"
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"github.com/rfjakob/gocryptfs/internal/openfiletable"
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"github.com/rfjakob/gocryptfs/internal/serialize_reads"
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"github.com/rfjakob/gocryptfs/internal/stupidgcm"
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"github.com/rfjakob/gocryptfs/internal/syscallcompat"
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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// File implements the go-fuse v2 API (github.com/hanwen/go-fuse/v2/fs)
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type File struct {
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fd *os.File
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// Has Release() already been called on this file? This also means that the
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// wlock entry has been freed, so let's not crash trying to access it.
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// Due to concurrency, Release can overtake other operations. These will
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// return EBADF in that case.
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released bool
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// fdLock prevents the fd to be closed while we are in the middle of
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// an operation.
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// Every FUSE entrypoint should RLock(). The only user of Lock() is
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// Release(), which closes the fd and sets "released" to true.
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fdLock sync.RWMutex
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// Content encryption helper
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contentEnc *contentenc.ContentEnc
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// Device and inode number uniquely identify the backing file
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qIno inomap.QIno
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// Entry in the open file table
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fileTableEntry *openfiletable.Entry
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// Store where the last byte was written
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lastWrittenOffset int64
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// The opCount is used to judge whether "lastWrittenOffset" is still
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// guaranteed to be correct.
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lastOpCount uint64
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// Parent filesystem
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rootNode *RootNode
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}
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// NewFile returns a new go-fuse File instance based on an already-open file
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// descriptor. NewFile internally calls Fstat() on the fd. The resulting Stat_t
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// is returned because node.Create() needs it.
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//
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// `cName` is only used for error logging and may be left blank.
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func NewFile(fd int, cName string, rn *RootNode) (f *File, st *syscall.Stat_t, errno syscall.Errno) {
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// Need device number and inode number for openfiletable locking
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st = &syscall.Stat_t{}
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if err := syscall.Fstat(fd, st); err != nil {
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errno = fs.ToErrno(err)
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return
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}
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qi := inomap.QInoFromStat(st)
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e := openfiletable.Register(qi)
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osFile := os.NewFile(uintptr(fd), cName)
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f = &File{
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fd: osFile,
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contentEnc: rn.contentEnc,
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qIno: qi,
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fileTableEntry: e,
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rootNode: rn,
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}
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return f, st, 0
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}
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// intFd - return the backing file descriptor as an integer.
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func (f *File) intFd() int {
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return int(f.fd.Fd())
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}
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// readFileID loads the file header from disk and extracts the file ID.
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// Returns io.EOF if the file is empty.
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func (f *File) readFileID() ([]byte, error) {
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// We read +1 byte to determine if the file has actual content
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// and not only the header. A header-only file will be considered empty.
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// This makes File ID poisoning more difficult.
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readLen := contentenc.HeaderLen + 1
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buf := make([]byte, readLen)
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n, err := f.fd.ReadAt(buf, 0)
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if err != nil {
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if err == io.EOF && n != 0 {
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tlog.Warn.Printf("readFileID %d: incomplete file, got %d instead of %d bytes",
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f.qIno.Ino, n, readLen)
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f.rootNode.reportMitigatedCorruption(fmt.Sprint(f.qIno.Ino))
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}
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return nil, err
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}
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buf = buf[:contentenc.HeaderLen]
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h, err := contentenc.ParseHeader(buf)
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if err != nil {
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return nil, err
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}
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return h.ID, nil
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}
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// createHeader creates a new random header and writes it to disk.
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// Returns the new file ID.
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// The caller must hold fileIDLock.Lock().
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func (f *File) createHeader() (fileID []byte, err error) {
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h := contentenc.RandomHeader()
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buf := h.Pack()
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// Prevent partially written (=corrupt) header by preallocating the space beforehand
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if !f.rootNode.args.NoPrealloc {
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err = syscallcompat.EnospcPrealloc(f.intFd(), 0, contentenc.HeaderLen)
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if err != nil {
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if !syscallcompat.IsENOSPC(err) {
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tlog.Warn.Printf("ino%d: createHeader: prealloc failed: %s\n", f.qIno.Ino, err.Error())
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}
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return nil, err
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}
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}
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// Actually write header
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_, err = f.fd.WriteAt(buf, 0)
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if err != nil {
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return nil, err
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}
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return h.ID, err
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}
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// doRead - read "length" plaintext bytes from plaintext offset "off" and append
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// to "dst".
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// Arguments "length" and "off" do not have to be block-aligned.
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//
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// doRead reads the corresponding ciphertext blocks from disk, decrypts them and
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// returns the requested part of the plaintext.
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//
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// Called by Read() for normal reading,
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// by Write() and Truncate() via doWrite() for Read-Modify-Write.
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func (f *File) doRead(dst []byte, off uint64, length uint64) ([]byte, syscall.Errno) {
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// Get the file ID, either from the open file table, or from disk.
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var fileID []byte
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f.fileTableEntry.IDLock.Lock()
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if f.fileTableEntry.ID != nil {
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// Use the cached value in the file table
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fileID = f.fileTableEntry.ID
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} else {
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// Not cached, we have to read it from disk.
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var err error
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fileID, err = f.readFileID()
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if err != nil {
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f.fileTableEntry.IDLock.Unlock()
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if err == io.EOF {
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// Empty file
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return nil, 0
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}
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buf := make([]byte, 100)
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n, _ := f.fd.ReadAt(buf, 0)
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buf = buf[:n]
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hexdump := hex.EncodeToString(buf)
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tlog.Warn.Printf("doRead %d: corrupt header: %v\nFile hexdump (%d bytes): %s",
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f.qIno.Ino, err, n, hexdump)
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return nil, syscall.EIO
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}
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// Save into the file table
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f.fileTableEntry.ID = fileID
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}
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f.fileTableEntry.IDLock.Unlock()
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if fileID == nil {
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log.Panicf("fileID=%v", fileID)
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}
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// Read the backing ciphertext in one go
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blocks := f.contentEnc.ExplodePlainRange(off, length)
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alignedOffset, alignedLength := blocks[0].JointCiphertextRange(blocks)
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// f.fd.ReadAt takes an int64!
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if alignedOffset > math.MaxInt64 {
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return nil, syscall.EFBIG
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}
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skip := blocks[0].Skip
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tlog.Debug.Printf("doRead: off=%d len=%d -> off=%d len=%d skip=%d\n",
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off, length, alignedOffset, alignedLength, skip)
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ciphertext := f.rootNode.contentEnc.CReqPool.Get()
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ciphertext = ciphertext[:int(alignedLength)]
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n, err := f.fd.ReadAt(ciphertext, int64(alignedOffset))
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if err != nil && err != io.EOF {
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tlog.Warn.Printf("read: ReadAt: %s", err.Error())
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return nil, fs.ToErrno(err)
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}
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// The ReadAt came back empty. We can skip all the decryption and return early.
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if n == 0 {
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f.rootNode.contentEnc.CReqPool.Put(ciphertext)
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return dst, 0
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}
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// Truncate ciphertext buffer down to actually read bytes
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ciphertext = ciphertext[0:n]
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firstBlockNo := blocks[0].BlockNo
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tlog.Debug.Printf("ReadAt offset=%d bytes (%d blocks), want=%d, got=%d", alignedOffset, firstBlockNo, alignedLength, n)
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// Decrypt it
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plaintext, err := f.contentEnc.DecryptBlocks(ciphertext, firstBlockNo, fileID)
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f.rootNode.contentEnc.CReqPool.Put(ciphertext)
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if err != nil {
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if f.rootNode.args.ForceDecode && err == stupidgcm.ErrAuth {
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// We do not have the information which block was corrupt here anymore,
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// but DecryptBlocks() has already logged it anyway.
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tlog.Warn.Printf("doRead %d: off=%d len=%d: returning corrupt data due to forcedecode",
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f.qIno.Ino, off, length)
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} else {
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curruptBlockNo := firstBlockNo + f.contentEnc.PlainOffToBlockNo(uint64(len(plaintext)))
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tlog.Warn.Printf("doRead %d: corrupt block #%d: %v", f.qIno.Ino, curruptBlockNo, err)
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return nil, syscall.EIO
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}
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}
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// Crop down to the relevant part
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var out []byte
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lenHave := len(plaintext)
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lenWant := int(skip + length)
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if lenHave > lenWant {
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out = plaintext[skip:lenWant]
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} else if lenHave > int(skip) {
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out = plaintext[skip:lenHave]
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}
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// else: out stays empty, file was smaller than the requested offset
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out = append(dst, out...)
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f.rootNode.contentEnc.PReqPool.Put(plaintext)
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return out, 0
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}
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// Read - FUSE call
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func (f *File) Read(ctx context.Context, buf []byte, off int64) (resultData fuse.ReadResult, errno syscall.Errno) {
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if len(buf) > fuse.MAX_KERNEL_WRITE {
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// This would crash us due to our fixed-size buffer pool
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tlog.Warn.Printf("Read: rejecting oversized request with EMSGSIZE, len=%d", len(buf))
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return nil, syscall.EMSGSIZE
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}
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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f.fileTableEntry.ContentLock.RLock()
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defer f.fileTableEntry.ContentLock.RUnlock()
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tlog.Debug.Printf("ino%d: FUSE Read: offset=%d length=%d", f.qIno.Ino, off, len(buf))
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if f.rootNode.args.SerializeReads {
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serialize_reads.Wait(off, len(buf))
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}
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out, errno := f.doRead(buf[:0], uint64(off), uint64(len(buf)))
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if f.rootNode.args.SerializeReads {
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serialize_reads.Done()
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}
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if errno != 0 {
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return nil, errno
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}
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tlog.Debug.Printf("ino%d: Read: errno=%d, returning %d bytes", f.qIno.Ino, errno, len(out))
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return fuse.ReadResultData(out), errno
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}
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// doWrite - encrypt "data" and write it to plaintext offset "off"
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//
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// Arguments do not have to be block-aligned, read-modify-write is
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// performed internally as necessary
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//
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// Called by Write() for normal writing,
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// and by Truncate() to rewrite the last file block.
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//
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// Empty writes do nothing and are allowed.
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func (f *File) doWrite(data []byte, off int64) (uint32, syscall.Errno) {
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fileWasEmpty := false
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// Get the file ID, create a new one if it does not exist yet.
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var fileID []byte
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// The caller has exclusively locked ContentLock, which blocks all other
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// readers and writers. No need to take IDLock.
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if f.fileTableEntry.ID != nil {
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fileID = f.fileTableEntry.ID
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} else {
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// If the file ID is not cached, read it from disk
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var err error
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fileID, err = f.readFileID()
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// Write a new file header if the file is empty
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if err == io.EOF {
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fileID, err = f.createHeader()
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fileWasEmpty = true
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}
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if err != nil {
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return 0, fs.ToErrno(err)
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}
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f.fileTableEntry.ID = fileID
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}
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// Handle payload data
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dataBuf := bytes.NewBuffer(data)
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blocks := f.contentEnc.ExplodePlainRange(uint64(off), uint64(len(data)))
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toEncrypt := make([][]byte, len(blocks))
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for i, b := range blocks {
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blockData := dataBuf.Next(int(b.Length))
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// Incomplete block -> Read-Modify-Write
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if b.IsPartial() {
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// Read
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oldData, errno := f.doRead(nil, b.BlockPlainOff(), f.contentEnc.PlainBS())
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if errno != 0 {
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tlog.Warn.Printf("ino%d fh%d: RMW read failed: errno=%d", f.qIno.Ino, f.intFd(), errno)
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return 0, errno
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}
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// Modify
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blockData = f.contentEnc.MergeBlocks(oldData, blockData, int(b.Skip))
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tlog.Debug.Printf("len(oldData)=%d len(blockData)=%d", len(oldData), len(blockData))
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}
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tlog.Debug.Printf("ino%d: Writing %d bytes to block #%d",
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f.qIno.Ino, len(blockData), b.BlockNo)
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// Write into the to-encrypt list
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toEncrypt[i] = blockData
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}
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// Encrypt all blocks
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ciphertext := f.contentEnc.EncryptBlocks(toEncrypt, blocks[0].BlockNo, f.fileTableEntry.ID)
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// Preallocate so we cannot run out of space in the middle of the write.
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// This prevents partially written (=corrupt) blocks.
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var err error
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cOff := blocks[0].BlockCipherOff()
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// f.fd.WriteAt & syscallcompat.EnospcPrealloc take int64 offsets!
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if cOff > math.MaxInt64 {
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return 0, syscall.EFBIG
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}
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if !f.rootNode.args.NoPrealloc {
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err = syscallcompat.EnospcPrealloc(f.intFd(), int64(cOff), int64(len(ciphertext)))
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if err != nil {
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if !syscallcompat.IsENOSPC(err) {
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tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %v", f.qIno.Ino, f.intFd(), err)
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}
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if fileWasEmpty {
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// Kill the file header again
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f.fileTableEntry.ID = nil
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err2 := syscall.Ftruncate(f.intFd(), 0)
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if err2 != nil {
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tlog.Warn.Printf("ino%d fh%d: doWrite: rollback failed: %v", f.qIno.Ino, f.intFd(), err2)
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}
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}
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return 0, fs.ToErrno(err)
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}
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}
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// Write
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_, err = f.fd.WriteAt(ciphertext, int64(cOff))
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// Return memory to CReqPool
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f.rootNode.contentEnc.CReqPool.Put(ciphertext)
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if err != nil {
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tlog.Warn.Printf("ino%d fh%d: doWrite: WriteAt off=%d len=%d failed: %v",
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f.qIno.Ino, f.intFd(), cOff, len(ciphertext), err)
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return 0, fs.ToErrno(err)
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}
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return uint32(len(data)), 0
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}
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// isConsecutiveWrite returns true if the current write
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// directly (in time and space) follows the last write.
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// This is an optimisation for streaming writes on NFS where a
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// Stat() call is very expensive.
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// The caller must "wlock.lock(f.devIno.ino)" otherwise this check would be racy.
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func (f *File) isConsecutiveWrite(off int64) bool {
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opCount := openfiletable.WriteOpCount()
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return opCount == f.lastOpCount+1 && off == f.lastWrittenOffset+1
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}
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// Write - FUSE call
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//
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// If the write creates a hole, pads the file to the next block boundary.
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func (f *File) Write(ctx context.Context, data []byte, off int64) (uint32, syscall.Errno) {
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if len(data) > fuse.MAX_KERNEL_WRITE {
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// This would crash us due to our fixed-size buffer pool
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tlog.Warn.Printf("Write: rejecting oversized request with EMSGSIZE, len=%d", len(data))
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return 0, syscall.EMSGSIZE
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}
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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if f.released {
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// The file descriptor has been closed concurrently
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tlog.Warn.Printf("ino%d fh%d: Write on released file", f.qIno.Ino, f.intFd())
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return 0, syscall.EBADF
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}
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f.fileTableEntry.ContentLock.Lock()
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defer f.fileTableEntry.ContentLock.Unlock()
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tlog.Debug.Printf("ino%d: FUSE Write: offset=%d length=%d", f.qIno.Ino, off, len(data))
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// If the write creates a file hole, we have to zero-pad the last block.
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// But if the write directly follows an earlier write, it cannot create a
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// hole, and we can save one Stat() call.
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if !f.isConsecutiveWrite(off) {
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errno := f.writePadHole(off)
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if errno != 0 {
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return 0, errno
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}
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}
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n, errno := f.doWrite(data, off)
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if errno != 0 {
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f.lastOpCount = openfiletable.WriteOpCount()
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f.lastWrittenOffset = off + int64(len(data)) - 1
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}
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return n, errno
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}
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// Release - FUSE call, close file
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func (f *File) Release(ctx context.Context) syscall.Errno {
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f.fdLock.Lock()
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if f.released {
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log.Panicf("ino%d fh%d: double release", f.qIno.Ino, f.intFd())
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}
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f.released = true
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openfiletable.Unregister(f.qIno)
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err := f.fd.Close()
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f.fdLock.Unlock()
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return fs.ToErrno(err)
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}
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// Flush - FUSE call
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func (f *File) Flush(ctx context.Context) syscall.Errno {
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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err := syscallcompat.Flush(f.intFd())
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return fs.ToErrno(err)
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}
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// Fsync FUSE call
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func (f *File) Fsync(ctx context.Context, flags uint32) (errno syscall.Errno) {
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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return fs.ToErrno(syscall.Fsync(f.intFd()))
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}
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// Getattr FUSE call (like stat)
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func (f *File) Getattr(ctx context.Context, a *fuse.AttrOut) syscall.Errno {
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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tlog.Debug.Printf("file.GetAttr()")
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st := syscall.Stat_t{}
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err := syscall.Fstat(f.intFd(), &st)
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if err != nil {
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return fs.ToErrno(err)
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}
|
|
f.rootNode.inoMap.TranslateStat(&st)
|
|
a.FromStat(&st)
|
|
a.Size = f.contentEnc.CipherSizeToPlainSize(a.Size)
|
|
if f.rootNode.args.ForceOwner != nil {
|
|
a.Owner = *f.rootNode.args.ForceOwner
|
|
}
|
|
|
|
return 0
|
|
}
|