1 files changed, 380 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/setstat.go b/pkg/sentry/syscalls/linux/vfs2/setstat.go
new file mode 100644
index 000000000..9250659ff
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/vfs2/setstat.go
@@ -0,0 +1,380 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package vfs2
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/fspath"
+	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+const chmodMask = 0777 | linux.S_ISUID | linux.S_ISGID | linux.S_ISVTX
+
+// Chmod implements Linux syscall chmod(2).
+func Chmod(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	pathAddr := args[0].Pointer()
+	mode := args[1].ModeT()
+	return 0, nil, fchmodat(t, linux.AT_FDCWD, pathAddr, mode)
+}
+
+// Fchmodat implements Linux syscall fchmodat(2).
+func Fchmodat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	dirfd := args[0].Int()
+	pathAddr := args[1].Pointer()
+	mode := args[2].ModeT()
+	return 0, nil, fchmodat(t, dirfd, pathAddr, mode)
+}
+
+func fchmodat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr, mode uint) error {
+	path, err := copyInPath(t, pathAddr)
+	if err != nil {
+		return err
+	}
+
+	return setstatat(t, dirfd, path, disallowEmptyPath, followFinalSymlink, &vfs.SetStatOptions{
+		Stat: linux.Statx{
+			Mask: linux.STATX_MODE,
+			Mode: uint16(mode & chmodMask),
+		},
+	})
+}
+
+// Fchmod implements Linux syscall fchmod(2).
+func Fchmod(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	fd := args[0].Int()
+	mode := args[1].ModeT()
+
+	file := t.GetFileVFS2(fd)
+	if file == nil {
+		return 0, nil, syserror.EBADF
+	}
+	defer file.DecRef()
+
+	return 0, nil, file.SetStat(t, vfs.SetStatOptions{
+		Stat: linux.Statx{
+			Mask: linux.STATX_MODE,
+			Mode: uint16(mode & chmodMask),
+		},
+	})
+}
+
+// Chown implements Linux syscall chown(2).
+func Chown(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	pathAddr := args[0].Pointer()
+	owner := args[1].Int()
+	group := args[2].Int()
+	return 0, nil, fchownat(t, linux.AT_FDCWD, pathAddr, owner, group, 0 /* flags */)
+}
+
+// Lchown implements Linux syscall lchown(2).
+func Lchown(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	pathAddr := args[0].Pointer()
+	owner := args[1].Int()
+	group := args[2].Int()
+	return 0, nil, fchownat(t, linux.AT_FDCWD, pathAddr, owner, group, linux.AT_SYMLINK_NOFOLLOW)
+}
+
+// Fchownat implements Linux syscall fchownat(2).
+func Fchownat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	dirfd := args[0].Int()
+	pathAddr := args[1].Pointer()
+	owner := args[2].Int()
+	group := args[3].Int()
+	flags := args[4].Int()
+	return 0, nil, fchownat(t, dirfd, pathAddr, owner, group, flags)
+}
+
+func fchownat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr, owner, group, flags int32) error {
+	if flags&^(linux.AT_EMPTY_PATH|linux.AT_SYMLINK_NOFOLLOW) != 0 {
+		return syserror.EINVAL
+	}
+
+	path, err := copyInPath(t, pathAddr)
+	if err != nil {
+		return err
+	}
+
+	var opts vfs.SetStatOptions
+	if err := populateSetStatOptionsForChown(t, owner, group, &opts); err != nil {
+		return err
+	}
+
+	return setstatat(t, dirfd, path, shouldAllowEmptyPath(flags&linux.AT_EMPTY_PATH != 0), shouldFollowFinalSymlink(flags&linux.AT_SYMLINK_NOFOLLOW == 0), &opts)
+}
+
+func populateSetStatOptionsForChown(t *kernel.Task, owner, group int32, opts *vfs.SetStatOptions) error {
+	userns := t.UserNamespace()
+	if owner != -1 {
+		kuid := userns.MapToKUID(auth.UID(owner))
+		if !kuid.Ok() {
+			return syserror.EINVAL
+		}
+		opts.Stat.Mask |= linux.STATX_UID
+		opts.Stat.UID = uint32(kuid)
+	}
+	if group != -1 {
+		kgid := userns.MapToKGID(auth.GID(group))
+		if !kgid.Ok() {
+			return syserror.EINVAL
+		}
+		opts.Stat.Mask |= linux.STATX_GID
+		opts.Stat.GID = uint32(kgid)
+	}
+	return nil
+}
+
+// Fchown implements Linux syscall fchown(2).
+func Fchown(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	fd := args[0].Int()
+	owner := args[1].Int()
+	group := args[2].Int()
+
+	file := t.GetFileVFS2(fd)
+	if file == nil {
+		return 0, nil, syserror.EBADF
+	}
+	defer file.DecRef()
+
+	var opts vfs.SetStatOptions
+	if err := populateSetStatOptionsForChown(t, owner, group, &opts); err != nil {
+		return 0, nil, err
+	}
+	return 0, nil, file.SetStat(t, opts)
+}
+
+// Truncate implements Linux syscall truncate(2).
+func Truncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	addr := args[0].Pointer()
+	length := args[1].Int64()
+
+	if length < 0 {
+		return 0, nil, syserror.EINVAL
+	}
+
+	path, err := copyInPath(t, addr)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	return 0, nil, setstatat(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink, &vfs.SetStatOptions{
+		Stat: linux.Statx{
+			Mask: linux.STATX_SIZE,
+			Size: uint64(length),
+		},
+	})
+}
+
+// Ftruncate implements Linux syscall ftruncate(2).
+func Ftruncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	fd := args[0].Int()
+	length := args[1].Int64()
+
+	if length < 0 {
+		return 0, nil, syserror.EINVAL
+	}
+
+	file := t.GetFileVFS2(fd)
+	if file == nil {
+		return 0, nil, syserror.EBADF
+	}
+	defer file.DecRef()
+
+	return 0, nil, file.SetStat(t, vfs.SetStatOptions{
+		Stat: linux.Statx{
+			Mask: linux.STATX_SIZE,
+			Size: uint64(length),
+		},
+	})
+}
+
+// Utime implements Linux syscall utime(2).
+func Utime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	pathAddr := args[0].Pointer()
+	timesAddr := args[1].Pointer()
+
+	path, err := copyInPath(t, pathAddr)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	opts := vfs.SetStatOptions{
+		Stat: linux.Statx{
+			Mask: linux.STATX_ATIME | linux.STATX_MTIME,
+		},
+	}
+	if timesAddr == 0 {
+		opts.Stat.Atime.Nsec = linux.UTIME_NOW
+		opts.Stat.Mtime.Nsec = linux.UTIME_NOW
+	} else {
+		var times linux.Utime
+		if err := times.CopyIn(t, timesAddr); err != nil {
+			return 0, nil, err
+		}
+		opts.Stat.Atime.Sec = times.Actime
+		opts.Stat.Mtime.Sec = times.Modtime
+	}
+
+	return 0, nil, setstatat(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink, &opts)
+}
+
+// Utimes implements Linux syscall utimes(2).
+func Utimes(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	pathAddr := args[0].Pointer()
+	timesAddr := args[1].Pointer()
+
+	path, err := copyInPath(t, pathAddr)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	opts := vfs.SetStatOptions{
+		Stat: linux.Statx{
+			Mask: linux.STATX_ATIME | linux.STATX_MTIME,
+		},
+	}
+	if timesAddr == 0 {
+		opts.Stat.Atime.Nsec = linux.UTIME_NOW
+		opts.Stat.Mtime.Nsec = linux.UTIME_NOW
+	} else {
+		var times [2]linux.Timeval
+		if _, err := t.CopyIn(timesAddr, &times); err != nil {
+			return 0, nil, err
+		}
+		opts.Stat.Atime = linux.StatxTimestamp{
+			Sec:  times[0].Sec,
+			Nsec: uint32(times[0].Usec * 1000),
+		}
+		opts.Stat.Mtime = linux.StatxTimestamp{
+			Sec:  times[1].Sec,
+			Nsec: uint32(times[1].Usec * 1000),
+		}
+	}
+
+	return 0, nil, setstatat(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink, &opts)
+}
+
+// Utimensat implements Linux syscall utimensat(2).
+func Utimensat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	dirfd := args[0].Int()
+	pathAddr := args[1].Pointer()
+	timesAddr := args[2].Pointer()
+	flags := args[3].Int()
+
+	if flags&^linux.AT_SYMLINK_NOFOLLOW != 0 {
+		return 0, nil, syserror.EINVAL
+	}
+
+	path, err := copyInPath(t, pathAddr)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	var opts vfs.SetStatOptions
+	if err := populateSetStatOptionsForUtimens(t, timesAddr, &opts); err != nil {
+		return 0, nil, err
+	}
+
+	return 0, nil, setstatat(t, dirfd, path, disallowEmptyPath, followFinalSymlink, &opts)
+}
+
+// Futimens implements Linux syscall futimens(2).
+func Futimens(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	fd := args[0].Int()
+	timesAddr := args[1].Pointer()
+
+	file := t.GetFileVFS2(fd)
+	if file == nil {
+		return 0, nil, syserror.EBADF
+	}
+	defer file.DecRef()
+
+	var opts vfs.SetStatOptions
+	if err := populateSetStatOptionsForUtimens(t, timesAddr, &opts); err != nil {
+		return 0, nil, err
+	}
+
+	return 0, nil, file.SetStat(t, opts)
+}
+
+func populateSetStatOptionsForUtimens(t *kernel.Task, timesAddr usermem.Addr, opts *vfs.SetStatOptions) error {
+	if timesAddr == 0 {
+		opts.Stat.Mask = linux.STATX_ATIME | linux.STATX_MTIME
+		opts.Stat.Atime.Nsec = linux.UTIME_NOW
+		opts.Stat.Mtime.Nsec = linux.UTIME_NOW
+		return nil
+	}
+	var times [2]linux.Timespec
+	if _, err := t.CopyIn(timesAddr, &times); err != nil {
+		return err
+	}
+	if times[0].Nsec != linux.UTIME_OMIT {
+		opts.Stat.Mask |= linux.STATX_ATIME
+		opts.Stat.Atime = linux.StatxTimestamp{
+			Sec:  times[0].Sec,
+			Nsec: uint32(times[0].Nsec),
+		}
+	}
+	if times[1].Nsec != linux.UTIME_OMIT {
+		opts.Stat.Mask |= linux.STATX_MTIME
+		opts.Stat.Mtime = linux.StatxTimestamp{
+			Sec:  times[1].Sec,
+			Nsec: uint32(times[1].Nsec),
+		}
+	}
+	return nil
+}
+
+func setstatat(t *kernel.Task, dirfd int32, path fspath.Path, shouldAllowEmptyPath shouldAllowEmptyPath, shouldFollowFinalSymlink shouldFollowFinalSymlink, opts *vfs.SetStatOptions) error {
+	root := t.FSContext().RootDirectoryVFS2()
+	defer root.DecRef()
+	start := root
+	if !path.Absolute {
+		if !path.HasComponents() && !bool(shouldAllowEmptyPath) {
+			return syserror.ENOENT
+		}
+		if dirfd == linux.AT_FDCWD {
+			start = t.FSContext().WorkingDirectoryVFS2()
+			defer start.DecRef()
+		} else {
+			dirfile := t.GetFileVFS2(dirfd)
+			if dirfile == nil {
+				return syserror.EBADF
+			}
+			if !path.HasComponents() {
+				// Use FileDescription.SetStat() instead of
+				// VirtualFilesystem.SetStatAt(), since the former may be able
+				// to use opened file state to expedite the SetStat.
+				err := dirfile.SetStat(t, *opts)
+				dirfile.DecRef()
+				return err
+			}
+			start = dirfile.VirtualDentry()
+			start.IncRef()
+			defer start.DecRef()
+			dirfile.DecRef()
+		}
+	}
+	return t.Kernel().VFS().SetStatAt(t, t.Credentials(), &vfs.PathOperation{
+		Root:               root,
+		Start:              start,
+		Path:               path,
+		FollowFinalSymlink: bool(shouldFollowFinalSymlink),
+	}, opts)
+}