From e99e8417137a713348d2797ba813bcefe0c3984d Mon Sep 17 00:00:00 2001 From: Jakob Unterwurzacher Date: Fri, 11 Dec 2015 19:54:53 +0100 Subject: Rmdir: handle creating and removing unreadable directories This patch also splits off Mkdir and Rmdir into its own file. Fixes issue #8, thanks to @diseq for the bug report. --- pathfs_frontend/fs.go | 99 ------------------------------ pathfs_frontend/fs_dir.go | 151 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 151 insertions(+), 99 deletions(-) create mode 100644 pathfs_frontend/fs_dir.go (limited to 'pathfs_frontend') diff --git a/pathfs_frontend/fs.go b/pathfs_frontend/fs.go index 8d05c02..c7a9888 100644 --- a/pathfs_frontend/fs.go +++ b/pathfs_frontend/fs.go @@ -2,7 +2,6 @@ package pathfs_frontend import ( "encoding/base64" - "fmt" "os" "path/filepath" "sync" @@ -245,40 +244,7 @@ func (fs *FS) Readlink(path string, context *fuse.Context) (out string, status f return string(target), fuse.OK } -func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fuse.Status) { - if fs.isFiltered(relPath) { - return fuse.EPERM - } - encPath, err := fs.getBackingPath(relPath) - if err != nil { - return fuse.ToStatus(err) - } - if !fs.args.DirIV { - return fuse.ToStatus(os.Mkdir(encPath, os.FileMode(mode))) - } - // The new directory may take the place of an older one that is still in the cache - fs.CryptFS.DirIVCacheEnc.Clear() - // Create directory - fs.dirIVLock.Lock() - defer fs.dirIVLock.Unlock() - err = os.Mkdir(encPath, os.FileMode(mode)) - if err != nil { - return fuse.ToStatus(err) - } - // Create gocryptfs.diriv inside - err = cryptfs.WriteDirIV(encPath) - if err != nil { - // This should not happen - cryptfs.Warn.Printf("Creating %s in dir %s failed: %v\n", cryptfs.DIRIV_FILENAME, encPath, err) - err2 := syscall.Rmdir(encPath) - if err2 != nil { - cryptfs.Warn.Printf("Mkdir: Rollback failed: %v\n", err2) - } - return fuse.ToStatus(err) - } - return fuse.OK -} func (fs *FS) Unlink(path string, context *fuse.Context) (code fuse.Status) { if fs.isFiltered(path) { @@ -291,71 +257,6 @@ func (fs *FS) Unlink(path string, context *fuse.Context) (code fuse.Status) { return fuse.ToStatus(syscall.Unlink(cPath)) } -func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) { - encPath, err := fs.getBackingPath(name) - if err != nil { - return fuse.ToStatus(err) - } - if !fs.args.DirIV { - return fuse.ToStatus(syscall.Rmdir(encPath)) - } - - // If the directory is not empty besides gocryptfs.diriv, do not even - // attempt the dance around gocryptfs.diriv. - fd, err := os.Open(encPath) - if err != nil { - return fuse.ToStatus(err) - } - defer fd.Close() - list, err := fd.Readdirnames(10) - if err != nil { - return fuse.ToStatus(err) - } - if len(list) > 1 { - return fuse.ToStatus(syscall.ENOTEMPTY) - } - - // Move "gocryptfs.diriv" to the parent dir under name "gocryptfs.diriv.rmdir.INODENUMBER" - var st syscall.Stat_t - err = syscall.Fstat(int(fd.Fd()), &st) - if err != nil { - return fuse.ToStatus(err) - } - dirivPath := filepath.Join(encPath, cryptfs.DIRIV_FILENAME) - parentDir := filepath.Dir(encPath) - tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", st.Ino) - tmpDirivPath := filepath.Join(parentDir, tmpName) - cryptfs.Debug.Printf("Rmdir: Renaming %s to %s\n", cryptfs.DIRIV_FILENAME, tmpDirivPath) - // The directory is in an inconsistent state between rename and rmdir. Protect against - // concurrent readers. - fs.dirIVLock.Lock() - defer fs.dirIVLock.Unlock() - err = os.Rename(dirivPath, tmpDirivPath) - if err != nil { - cryptfs.Warn.Printf("Rmdir: Renaming %s to %s failed: %v\n", cryptfs.DIRIV_FILENAME, tmpDirivPath, err) - return fuse.ToStatus(err) - } - // Actual Rmdir - err = syscall.Rmdir(encPath) - if err != nil { - // This can happen if another file in the directory was created in the - // meantime, undo the rename - err2 := os.Rename(tmpDirivPath, dirivPath) - if err2 != nil { - cryptfs.Warn.Printf("Rmdir: Rollback failed: %v\n", err2) - } - return fuse.ToStatus(err) - } - // Delete "gocryptfs.diriv.rmdir.INODENUMBER" - err = syscall.Unlink(tmpDirivPath) - if err != nil { - cryptfs.Warn.Printf("Rmdir: Could not clean up %s: %v\n", tmpName, err) - } - // The now-deleted directory may have been in the DirIV cache. Clear it. - fs.CryptFS.DirIVCacheEnc.Clear() - return fuse.OK -} - func (fs *FS) Symlink(target string, linkName string, context *fuse.Context) (code fuse.Status) { cryptfs.Debug.Printf("Symlink(\"%s\", \"%s\")\n", target, linkName) if fs.isFiltered(linkName) { diff --git a/pathfs_frontend/fs_dir.go b/pathfs_frontend/fs_dir.go new file mode 100644 index 0000000..95257bb --- /dev/null +++ b/pathfs_frontend/fs_dir.go @@ -0,0 +1,151 @@ +package pathfs_frontend + +import ( + "os" + "path/filepath" + "syscall" + "fmt" + + "github.com/hanwen/go-fuse/fuse" + "github.com/rfjakob/gocryptfs/cryptfs" +) + +func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fuse.Status) { + if fs.isFiltered(relPath) { + return fuse.EPERM + } + encPath, err := fs.getBackingPath(relPath) + if err != nil { + return fuse.ToStatus(err) + } + if !fs.args.DirIV { + return fuse.ToStatus(os.Mkdir(encPath, os.FileMode(mode))) + } + + // We need write and execute permissions to create gocryptfs.diriv + origMode := mode + mode = mode | 0300 + + // The new directory may take the place of an older one that is still in the cache + fs.CryptFS.DirIVCacheEnc.Clear() + // Create directory + fs.dirIVLock.Lock() + defer fs.dirIVLock.Unlock() + err = os.Mkdir(encPath, os.FileMode(mode)) + if err != nil { + return fuse.ToStatus(err) + } + // Create gocryptfs.diriv inside + err = cryptfs.WriteDirIV(encPath) + if err != nil { + // This should not happen + cryptfs.Warn.Printf("Mkdir: WriteDirIV failed: %v\n", err) + err2 := syscall.Rmdir(encPath) + if err2 != nil { + cryptfs.Warn.Printf("Mkdir: Rmdir rollback failed: %v\n", err2) + } + return fuse.ToStatus(err) + } + + // Set permissions back to what the user wanted + if origMode != mode { + err = os.Chmod(encPath, os.FileMode(origMode)) + if err != nil { + cryptfs.Warn.Printf("Mkdir: Chmod failed: %v\n", err) + } + } + + return fuse.OK +} + +func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) { + encPath, err := fs.getBackingPath(name) + if err != nil { + return fuse.ToStatus(err) + } + if !fs.args.DirIV { + return fuse.ToStatus(syscall.Rmdir(encPath)) + } + + // If the directory is not empty besides gocryptfs.diriv, do not even + // attempt the dance around gocryptfs.diriv. + fd, err := os.Open(encPath) + if perr, ok := err.(*os.PathError); ok && perr.Err == syscall.EACCES { + // We need permission to read and modify the directory + cryptfs.Debug.Printf("Rmdir: handling EACCESS\n") + fi, err2 := os.Stat(encPath) + if err2 != nil { + cryptfs.Debug.Printf("Rmdir: Stat: %v\n", err2) + return fuse.ToStatus(err2) + } + origMode := fi.Mode() + newMode := origMode | 0700 + err2 = os.Chmod(encPath, newMode) + if err2 != nil { + cryptfs.Debug.Printf("Rmdir: Chmod failed: %v\n", err2) + return fuse.ToStatus(err) + } + defer func () { + if code != fuse.OK { + // Undo the chmod if removing the directory failed + err3 := os.Chmod(encPath, origMode) + if err3 != nil { + cryptfs.Warn.Printf("Rmdir: Chmod rollback failed: %v\n", err2) + } + } + }() + // Retry open + fd, err = os.Open(encPath) + } + if err != nil { + cryptfs.Debug.Printf("Rmdir: Open: %v\n", err) + return fuse.ToStatus(err) + } + list, err := fd.Readdirnames(10) + fd.Close() + if err != nil { + cryptfs.Debug.Printf("Rmdir: Readdirnames: %v\n", err) + return fuse.ToStatus(err) + } + if len(list) > 1 { + return fuse.ToStatus(syscall.ENOTEMPTY) + } else if len(list) == 0 { + cryptfs.Warn.Printf("Rmdir: gocryptfs.diriv missing, allowing deletion\n") + return fuse.ToStatus(syscall.Rmdir(encPath)) + } + + // Move "gocryptfs.diriv" to the parent dir as "gocryptfs.diriv.rmdir.XYZ" + dirivPath := filepath.Join(encPath, cryptfs.DIRIV_FILENAME) + parentDir := filepath.Dir(encPath) + tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", cryptfs.RandUint64()) + tmpDirivPath := filepath.Join(parentDir, tmpName) + cryptfs.Debug.Printf("Rmdir: Renaming %s to %s\n", cryptfs.DIRIV_FILENAME, tmpDirivPath) + // The directory is in an inconsistent state between rename and rmdir. Protect against + // concurrent readers. + fs.dirIVLock.Lock() + defer fs.dirIVLock.Unlock() + err = os.Rename(dirivPath, tmpDirivPath) + if err != nil { + cryptfs.Warn.Printf("Rmdir: Renaming %s to %s failed: %v\n", cryptfs.DIRIV_FILENAME, tmpDirivPath, err) + return fuse.ToStatus(err) + } + // Actual Rmdir + err = syscall.Rmdir(encPath) + if err != nil { + // This can happen if another file in the directory was created in the + // meantime, undo the rename + err2 := os.Rename(tmpDirivPath, dirivPath) + if err2 != nil { + cryptfs.Warn.Printf("Rmdir: Rename rollback failed: %v\n", err2) + } + return fuse.ToStatus(err) + } + // Delete "gocryptfs.diriv.rmdir.INODENUMBER" + err = syscall.Unlink(tmpDirivPath) + if err != nil { + cryptfs.Warn.Printf("Rmdir: Could not clean up %s: %v\n", tmpName, err) + } + // The now-deleted directory may have been in the DirIV cache. Clear it. + fs.CryptFS.DirIVCacheEnc.Clear() + return fuse.OK +} -- cgit v1.2.3