diff --git a/internal/fusefrontend_reverse/rfs.go b/internal/fusefrontend_reverse/rfs.go index db10ce0..d87a936 100644 --- a/internal/fusefrontend_reverse/rfs.go +++ b/internal/fusefrontend_reverse/rfs.go @@ -201,11 +201,16 @@ func (rfs *ReverseFS) Access(relPath string, mode uint32, context *fuse.Context) } return fuse.EPERM } - absPath, err := rfs.abs(rfs.decryptPath(relPath)) + dirfd, name, err := rfs.openBackingDir(relPath) if err != nil { return fuse.ToStatus(err) } - return fuse.ToStatus(syscall.Access(absPath, mode)) + err = syscallcompat.Faccessat(dirfd, name, mode) + if err != nil { + fmt.Printf("name=%q err=%v", name, err) + } + syscall.Close(dirfd) + return fuse.ToStatus(err) } // Open - FUSE call diff --git a/internal/fusefrontend_reverse/rpath.go b/internal/fusefrontend_reverse/rpath.go index fa7680f..2dc76e1 100644 --- a/internal/fusefrontend_reverse/rpath.go +++ b/internal/fusefrontend_reverse/rpath.go @@ -8,6 +8,7 @@ import ( "github.com/rfjakob/gocryptfs/internal/nametransform" "github.com/rfjakob/gocryptfs/internal/pathiv" + "github.com/rfjakob/gocryptfs/internal/syscallcompat" "github.com/rfjakob/gocryptfs/internal/tlog" ) @@ -89,3 +90,23 @@ func (rfs *ReverseFS) decryptPath(relPath string) (string, error) { rPathCache.store(cDir, dirIV, nametransform.Dir(pRelPath)) return pRelPath, nil } + +// openBackingDir decrypt the relative ciphertext path "cRelPath", opens +// the directory that contains the target file/dir and returns the fd to +// the directory and the decrypted name of the target file. +// The fd/name pair is intended for use with fchownat and friends. +func (rfs *ReverseFS) openBackingDir(cRelPath string) (dirfd int, pName string, err error) { + // Decrypt relative path + pRelPath, err := rfs.decryptPath(cRelPath) + if err != nil { + return -1, "", err + } + // Open directory, safe against symlink races + pDir := filepath.Dir(pRelPath) + dirfd, err = syscallcompat.OpenNofollow(rfs.args.Cipherdir, pDir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0) + if err != nil { + return -1, "", err + } + pName = filepath.Base(pRelPath) + return dirfd, pName, nil +} diff --git a/tests/reverse/correctness_test.go b/tests/reverse/correctness_test.go index 63043b7..15eb18b 100644 --- a/tests/reverse/correctness_test.go +++ b/tests/reverse/correctness_test.go @@ -8,7 +8,10 @@ import ( "syscall" "testing" + "golang.org/x/sys/unix" + "github.com/rfjakob/gocryptfs/internal/ctlsock" + "github.com/rfjakob/gocryptfs/internal/syscallcompat" "github.com/rfjakob/gocryptfs/tests/test_helpers" ) @@ -138,6 +141,35 @@ func TestAccessVirtual(t *testing.T) { } } +// Check that the access() syscall works on regular files +func TestAccess(t *testing.T) { + f, err := os.Create(dirA + "/testaccess1") + if err != nil { + t.Fatal(err) + } + f.Close() + f, err = os.Open(dirB) + if err != nil { + t.Fatal(err) + } + names, err := f.Readdirnames(0) + if err != nil { + t.Fatal(err) + } + for _, n := range names { + // Check if file exists - this should never fail + err = syscallcompat.Faccessat(unix.AT_FDCWD, dirB+"/"+n, unix.F_OK) + if err != nil { + t.Errorf("%s: %v", n, err) + } + // Check if file is readable + err = syscallcompat.Faccessat(unix.AT_FDCWD, dirB+"/"+n, unix.R_OK) + if err != nil { + t.Logf("%s: %v", n, err) + } + } +} + // Opening a nonexistant file name should return ENOENT // and not EBADMSG or EIO or anything else. func TestEnoent(t *testing.T) {