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-rw-r--r--pkg/sentry/fsbridge/BUILD24
-rw-r--r--pkg/sentry/fsbridge/bridge.go54
-rw-r--r--pkg/sentry/fsbridge/fs.go181
-rw-r--r--pkg/sentry/fsbridge/vfs.go134
4 files changed, 393 insertions, 0 deletions
diff --git a/pkg/sentry/fsbridge/BUILD b/pkg/sentry/fsbridge/BUILD
new file mode 100644
index 000000000..6c798f0bd
--- /dev/null
+++ b/pkg/sentry/fsbridge/BUILD
@@ -0,0 +1,24 @@
+load("//tools:defs.bzl", "go_library")
+
+licenses(["notice"])
+
+go_library(
+ name = "fsbridge",
+ srcs = [
+ "bridge.go",
+ "fs.go",
+ "vfs.go",
+ ],
+ visibility = ["//pkg/sentry:internal"],
+ deps = [
+ "//pkg/abi/linux",
+ "//pkg/context",
+ "//pkg/fspath",
+ "//pkg/sentry/fs",
+ "//pkg/sentry/kernel/auth",
+ "//pkg/sentry/memmap",
+ "//pkg/sentry/vfs",
+ "//pkg/syserror",
+ "//pkg/usermem",
+ ],
+)
diff --git a/pkg/sentry/fsbridge/bridge.go b/pkg/sentry/fsbridge/bridge.go
new file mode 100644
index 000000000..8e7590721
--- /dev/null
+++ b/pkg/sentry/fsbridge/bridge.go
@@ -0,0 +1,54 @@
+// 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 fsbridge provides common interfaces to bridge between VFS1 and VFS2
+// files.
+package fsbridge
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+// File provides a common interface to bridge between VFS1 and VFS2 files.
+type File interface {
+ // PathnameWithDeleted returns an absolute pathname to vd, consistent with
+ // Linux's d_path(). In particular, if vd.Dentry() has been disowned,
+ // PathnameWithDeleted appends " (deleted)" to the returned pathname.
+ PathnameWithDeleted(ctx context.Context) string
+
+ // ReadFull read all contents from the file.
+ ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error)
+
+ // ConfigureMMap mutates opts to implement mmap(2) for the file.
+ ConfigureMMap(context.Context, *memmap.MMapOpts) error
+
+ // Type returns the file type, e.g. linux.S_IFREG.
+ Type(context.Context) (linux.FileMode, error)
+
+ // IncRef increments reference.
+ IncRef()
+
+ // DecRef decrements reference.
+ DecRef()
+}
+
+// Lookup provides a common interface to open files.
+type Lookup interface {
+ // OpenPath opens a file.
+ OpenPath(ctx context.Context, path string, opts vfs.OpenOptions, remainingTraversals *uint, resolveFinal bool) (File, error)
+}
diff --git a/pkg/sentry/fsbridge/fs.go b/pkg/sentry/fsbridge/fs.go
new file mode 100644
index 000000000..093ce1fb3
--- /dev/null
+++ b/pkg/sentry/fsbridge/fs.go
@@ -0,0 +1,181 @@
+// 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 fsbridge
+
+import (
+ "io"
+ "strings"
+
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/fs"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+// fsFile implements File interface over fs.File.
+//
+// +stateify savable
+type fsFile struct {
+ file *fs.File
+}
+
+var _ File = (*fsFile)(nil)
+
+// NewFSFile creates a new File over fs.File.
+func NewFSFile(file *fs.File) File {
+ return &fsFile{file: file}
+}
+
+// PathnameWithDeleted implements File.
+func (f *fsFile) PathnameWithDeleted(ctx context.Context) string {
+ root := fs.RootFromContext(ctx)
+ if root == nil {
+ // This doesn't correspond to anything in Linux because the vfs is
+ // global there.
+ return ""
+ }
+ defer root.DecRef()
+
+ name, _ := f.file.Dirent.FullName(root)
+ return name
+}
+
+// ReadFull implements File.
+func (f *fsFile) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) {
+ var total int64
+ for dst.NumBytes() > 0 {
+ n, err := f.file.Preadv(ctx, dst, offset+total)
+ total += n
+ if err == io.EOF && total != 0 {
+ return total, io.ErrUnexpectedEOF
+ } else if err != nil {
+ return total, err
+ }
+ dst = dst.DropFirst64(n)
+ }
+ return total, nil
+}
+
+// ConfigureMMap implements File.
+func (f *fsFile) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
+ return f.file.ConfigureMMap(ctx, opts)
+}
+
+// Type implements File.
+func (f *fsFile) Type(context.Context) (linux.FileMode, error) {
+ return linux.FileMode(f.file.Dirent.Inode.StableAttr.Type.LinuxType()), nil
+}
+
+// IncRef implements File.
+func (f *fsFile) IncRef() {
+ f.file.IncRef()
+}
+
+// DecRef implements File.
+func (f *fsFile) DecRef() {
+ f.file.DecRef()
+}
+
+// fsLookup implements Lookup interface using fs.File.
+//
+// +stateify savable
+type fsLookup struct {
+ mntns *fs.MountNamespace
+
+ root *fs.Dirent
+ workingDir *fs.Dirent
+}
+
+var _ Lookup = (*fsLookup)(nil)
+
+// NewFSLookup creates a new Lookup using VFS1.
+func NewFSLookup(mntns *fs.MountNamespace, root, workingDir *fs.Dirent) Lookup {
+ return &fsLookup{
+ mntns: mntns,
+ root: root,
+ workingDir: workingDir,
+ }
+}
+
+// OpenPath implements Lookup.
+func (l *fsLookup) OpenPath(ctx context.Context, path string, opts vfs.OpenOptions, remainingTraversals *uint, resolveFinal bool) (File, error) {
+ var d *fs.Dirent
+ var err error
+ if resolveFinal {
+ d, err = l.mntns.FindInode(ctx, l.root, l.workingDir, path, remainingTraversals)
+ } else {
+ d, err = l.mntns.FindLink(ctx, l.root, l.workingDir, path, remainingTraversals)
+ }
+ if err != nil {
+ return nil, err
+ }
+ defer d.DecRef()
+
+ if !resolveFinal && fs.IsSymlink(d.Inode.StableAttr) {
+ return nil, syserror.ELOOP
+ }
+
+ fsPerm := openOptionsToPermMask(&opts)
+ if err := d.Inode.CheckPermission(ctx, fsPerm); err != nil {
+ return nil, err
+ }
+
+ // If they claim it's a directory, then make sure.
+ if strings.HasSuffix(path, "/") {
+ if d.Inode.StableAttr.Type != fs.Directory {
+ return nil, syserror.ENOTDIR
+ }
+ }
+
+ if opts.FileExec && d.Inode.StableAttr.Type != fs.RegularFile {
+ ctx.Infof("%q is not a regular file: %v", path, d.Inode.StableAttr.Type)
+ return nil, syserror.EACCES
+ }
+
+ f, err := d.Inode.GetFile(ctx, d, flagsToFileFlags(opts.Flags))
+ if err != nil {
+ return nil, err
+ }
+
+ return &fsFile{file: f}, nil
+}
+
+func openOptionsToPermMask(opts *vfs.OpenOptions) fs.PermMask {
+ mode := opts.Flags & linux.O_ACCMODE
+ return fs.PermMask{
+ Read: mode == linux.O_RDONLY || mode == linux.O_RDWR,
+ Write: mode == linux.O_WRONLY || mode == linux.O_RDWR,
+ Execute: opts.FileExec,
+ }
+}
+
+func flagsToFileFlags(flags uint32) fs.FileFlags {
+ return fs.FileFlags{
+ Direct: flags&linux.O_DIRECT != 0,
+ DSync: flags&(linux.O_DSYNC|linux.O_SYNC) != 0,
+ Sync: flags&linux.O_SYNC != 0,
+ NonBlocking: flags&linux.O_NONBLOCK != 0,
+ Read: (flags & linux.O_ACCMODE) != linux.O_WRONLY,
+ Write: (flags & linux.O_ACCMODE) != linux.O_RDONLY,
+ Append: flags&linux.O_APPEND != 0,
+ Directory: flags&linux.O_DIRECTORY != 0,
+ Async: flags&linux.O_ASYNC != 0,
+ LargeFile: flags&linux.O_LARGEFILE != 0,
+ Truncate: flags&linux.O_TRUNC != 0,
+ }
+}
diff --git a/pkg/sentry/fsbridge/vfs.go b/pkg/sentry/fsbridge/vfs.go
new file mode 100644
index 000000000..e657c39bc
--- /dev/null
+++ b/pkg/sentry/fsbridge/vfs.go
@@ -0,0 +1,134 @@
+// 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 fsbridge
+
+import (
+ "io"
+
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/fspath"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+// fsFile implements File interface over vfs.FileDescription.
+//
+// +stateify savable
+type vfsFile struct {
+ file *vfs.FileDescription
+}
+
+var _ File = (*vfsFile)(nil)
+
+// NewVFSFile creates a new File over fs.File.
+func NewVFSFile(file *vfs.FileDescription) File {
+ return &vfsFile{file: file}
+}
+
+// PathnameWithDeleted implements File.
+func (f *vfsFile) PathnameWithDeleted(ctx context.Context) string {
+ root := vfs.RootFromContext(ctx)
+ defer root.DecRef()
+
+ vfsObj := f.file.VirtualDentry().Mount().Filesystem().VirtualFilesystem()
+ name, _ := vfsObj.PathnameWithDeleted(ctx, root, f.file.VirtualDentry())
+ return name
+}
+
+// ReadFull implements File.
+func (f *vfsFile) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) {
+ var total int64
+ for dst.NumBytes() > 0 {
+ n, err := f.file.PRead(ctx, dst, offset+total, vfs.ReadOptions{})
+ total += n
+ if err == io.EOF && total != 0 {
+ return total, io.ErrUnexpectedEOF
+ } else if err != nil {
+ return total, err
+ }
+ dst = dst.DropFirst64(n)
+ }
+ return total, nil
+}
+
+// ConfigureMMap implements File.
+func (f *vfsFile) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
+ return f.file.ConfigureMMap(ctx, opts)
+}
+
+// Type implements File.
+func (f *vfsFile) Type(ctx context.Context) (linux.FileMode, error) {
+ stat, err := f.file.Stat(ctx, vfs.StatOptions{})
+ if err != nil {
+ return 0, err
+ }
+ return linux.FileMode(stat.Mode).FileType(), nil
+}
+
+// IncRef implements File.
+func (f *vfsFile) IncRef() {
+ f.file.IncRef()
+}
+
+// DecRef implements File.
+func (f *vfsFile) DecRef() {
+ f.file.DecRef()
+}
+
+// fsLookup implements Lookup interface using fs.File.
+//
+// +stateify savable
+type vfsLookup struct {
+ mntns *vfs.MountNamespace
+
+ root vfs.VirtualDentry
+ workingDir vfs.VirtualDentry
+}
+
+var _ Lookup = (*vfsLookup)(nil)
+
+// NewVFSLookup creates a new Lookup using VFS2.
+func NewVFSLookup(mntns *vfs.MountNamespace, root, workingDir vfs.VirtualDentry) Lookup {
+ return &vfsLookup{
+ mntns: mntns,
+ root: root,
+ workingDir: workingDir,
+ }
+}
+
+// OpenPath implements Lookup.
+//
+// remainingTraversals is not configurable in VFS2, all callers are using the
+// default anyways.
+//
+// TODO(gvisor.dev/issue/1623): Check mount has read and exec permission.
+func (l *vfsLookup) OpenPath(ctx context.Context, path string, opts vfs.OpenOptions, _ *uint, resolveFinal bool) (File, error) {
+ vfsObj := l.mntns.Root().Mount().Filesystem().VirtualFilesystem()
+ creds := auth.CredentialsFromContext(ctx)
+ pop := &vfs.PathOperation{
+ Root: l.root,
+ Start: l.root,
+ Path: fspath.Parse(path),
+ FollowFinalSymlink: resolveFinal,
+ }
+ fd, err := vfsObj.OpenAt(ctx, creds, pop, &opts)
+ if err != nil {
+ return nil, err
+ }
+ return &vfsFile{file: fd}, nil
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 09:36:28 +0000