diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go index 5fe866b..dac7510 100644 --- a/internal/fusefrontend/file.go +++ b/internal/fusefrontend/file.go @@ -91,11 +91,20 @@ func (f *file) SetInode(n *nodefs.Inode) { // readFileID loads the file header from disk and extracts the file ID. // Returns io.EOF if the file is empty. func (f *file) readFileID() ([]byte, error) { - buf := make([]byte, contentenc.HeaderLen) - _, err := f.fd.ReadAt(buf, 0) + // We read +1 byte to determine if the file has actual content + // and not only the header. A header-only file will be considered empty. + // This makes File ID poisoning more difficult. + readLen := contentenc.HeaderLen + 1 + buf := make([]byte, readLen) + n, err := f.fd.ReadAt(buf, 0) if err != nil { + if err == io.EOF && n != 0 { + tlog.Warn.Printf("ino%d: readFileID: incomplete file, got %d instead of %d bytes", + f.devIno.ino, n, readLen) + } return nil, err } + buf = buf[:contentenc.HeaderLen] h, err := contentenc.ParseHeader(buf) if err != nil { return nil, err