Merge 216da0b7 (automated)

2 files changed, 300 insertions, 0 deletions

diff --git a/pkg/sentry/fs/binder/binder.go b/pkg/sentry/fs/binder/binder.go
new file mode 100644
index 000000000..c78f1fc40
--- /dev/null
+++ b/pkg/sentry/fs/binder/binder.go
@@ -0,0 +1,260 @@
+// Copyright 2018 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 binder implements Android Binder IPC module.
+package binder
+
+import (
+	"sync"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/pgalloc"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/platform"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usage"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+	"gvisor.googlesource.com/gvisor/pkg/waiter"
+)
+
+const (
+	currentProtocolVersion = 8
+
+	// mmapSizeLimit is the upper limit for mapped memory size in Binder.
+	mmapSizeLimit = 4 * 1024 * 1024 // 4MB
+)
+
+// Device implements fs.InodeOperations.
+//
+// +stateify savable
+type Device struct {
+	fsutil.InodeGenericChecker       `state:"nosave"`
+	fsutil.InodeNoExtendedAttributes `state:"nosave"`
+	fsutil.InodeNoopAllocate         `state:"nosave"`
+	fsutil.InodeNoopRelease          `state:"nosave"`
+	fsutil.InodeNoopTruncate         `state:"nosave"`
+	fsutil.InodeNoopWriteOut         `state:"nosave"`
+	fsutil.InodeNotDirectory         `state:"nosave"`
+	fsutil.InodeNotMappable          `state:"nosave"`
+	fsutil.InodeNotSocket            `state:"nosave"`
+	fsutil.InodeNotSymlink           `state:"nosave"`
+	fsutil.InodeVirtual              `state:"nosave"`
+
+	fsutil.InodeSimpleAttributes
+}
+
+var _ fs.InodeOperations = (*Device)(nil)
+
+// NewDevice creates and intializes a Device structure.
+func NewDevice(ctx context.Context, owner fs.FileOwner, fp fs.FilePermissions) *Device {
+	return &Device{
+		InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fp, 0),
+	}
+}
+
+// GetFile implements fs.InodeOperations.GetFile.
+//
+// TODO(b/30946773): Add functionality to GetFile: Additional fields will be
+// needed in the Device structure, initialize them here. Also, Device will need
+// to keep track of the created Procs in order to implement BINDER_READ_WRITE
+// ioctl.
+func (bd *Device) GetFile(ctx context.Context, d *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
+	return fs.NewFile(ctx, d, flags, &Proc{
+		bd:   bd,
+		task: kernel.TaskFromContext(ctx),
+		mfp:  pgalloc.MemoryFileProviderFromContext(ctx),
+	}), nil
+}
+
+// Proc implements fs.FileOperations and fs.IoctlGetter.
+//
+// +stateify savable
+type Proc struct {
+	fsutil.FileNoFsync              `state:"nosave"`
+	fsutil.FileNoSplice             `state:"nosave"`
+	fsutil.FileNotDirReaddir        `state:"nosave"`
+	fsutil.FileUseInodeUnstableAttr `state:"nosave"`
+	waiter.AlwaysReady              `state:"nosave"`
+
+	bd   *Device
+	task *kernel.Task
+	mfp  pgalloc.MemoryFileProvider
+
+	// mu protects fr.
+	mu sync.Mutex `state:"nosave"`
+
+	// mapped is memory allocated from mfp.MemoryFile() by AddMapping.
+	mapped platform.FileRange
+}
+
+// Release implements fs.FileOperations.Release.
+func (bp *Proc) Release() {
+	bp.mu.Lock()
+	defer bp.mu.Unlock()
+	if bp.mapped.Length() != 0 {
+		bp.mfp.MemoryFile().DecRef(bp.mapped)
+	}
+}
+
+// Seek implements fs.FileOperations.Seek.
+//
+// Binder doesn't support seek operation (unless in debug mode).
+func (bp *Proc) Seek(ctx context.Context, file *fs.File, whence fs.SeekWhence, offset int64) (int64, error) {
+	return offset, syserror.EOPNOTSUPP
+}
+
+// Read implements fs.FileOperations.Read.
+//
+// Binder doesn't support read operation (unless in debug mode).
+func (bp *Proc) Read(ctx context.Context, file *fs.File, dst usermem.IOSequence, offset int64) (int64, error) {
+	return 0, syserror.EOPNOTSUPP
+}
+
+// Write implements fs.FileOperations.Write.
+//
+// Binder doesn't support write operation.
+func (bp *Proc) Write(ctx context.Context, file *fs.File, src usermem.IOSequence, offset int64) (int64, error) {
+	return 0, syserror.EOPNOTSUPP
+}
+
+// Flush implements fs.FileOperations.Flush.
+//
+// TODO(b/30946773): Implement.
+func (bp *Proc) Flush(ctx context.Context, file *fs.File) error {
+	return nil
+}
+
+// ConfigureMMap implements fs.FileOperations.ConfigureMMap.
+func (bp *Proc) ConfigureMMap(ctx context.Context, file *fs.File, opts *memmap.MMapOpts) error {
+	// Compare drivers/android/binder.c:binder_mmap().
+	if caller := kernel.TaskFromContext(ctx); caller != bp.task {
+		return syserror.EINVAL
+	}
+	if opts.Length > mmapSizeLimit {
+		opts.Length = mmapSizeLimit
+	}
+	opts.MaxPerms.Write = false
+
+	// TODO(b/30946773): Binder sets VM_DONTCOPY, preventing the created vma
+	// from being copied across fork(), but we don't support this yet. As
+	// a result, MMs containing a Binder mapping cannot be forked (MM.Fork will
+	// fail when AddMapping returns EBUSY).
+
+	return fsutil.GenericConfigureMMap(file, bp, opts)
+}
+
+// Ioctl implements fs.FileOperations.Ioctl.
+//
+// TODO(b/30946773): Implement.
+func (bp *Proc) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) {
+	// Switch on ioctl request.
+	switch uint32(args[1].Int()) {
+	case linux.BinderVersionIoctl:
+		ver := &linux.BinderVersion{
+			ProtocolVersion: currentProtocolVersion,
+		}
+		// Copy result to user-space.
+		_, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), ver, usermem.IOOpts{
+			AddressSpaceActive: true,
+		})
+		return 0, err
+	case linux.BinderWriteReadIoctl:
+		// TODO(b/30946773): Implement.
+		fallthrough
+	case linux.BinderSetIdleTimeoutIoctl:
+		// TODO(b/30946773): Implement.
+		fallthrough
+	case linux.BinderSetMaxThreadsIoctl:
+		// TODO(b/30946773): Implement.
+		fallthrough
+	case linux.BinderSetIdlePriorityIoctl:
+		// TODO(b/30946773): Implement.
+		fallthrough
+	case linux.BinderSetContextMgrIoctl:
+		// TODO(b/30946773): Implement.
+		fallthrough
+	case linux.BinderThreadExitIoctl:
+		// TODO(b/30946773): Implement.
+		return 0, syserror.ENOSYS
+	default:
+		// Ioctls irrelevant to Binder.
+		return 0, syserror.EINVAL
+	}
+}
+
+// AddMapping implements memmap.Mappable.AddMapping.
+func (bp *Proc) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, _ bool) error {
+	bp.mu.Lock()
+	defer bp.mu.Unlock()
+	if bp.mapped.Length() != 0 {
+		// mmap has been called before, which binder_mmap() doesn't like.
+		return syserror.EBUSY
+	}
+	// Binder only allocates and maps a single page up-front
+	// (drivers/android/binder.c:binder_mmap() => binder_update_page_range()).
+	fr, err := bp.mfp.MemoryFile().Allocate(usermem.PageSize, usage.Anonymous)
+	if err != nil {
+		return err
+	}
+	bp.mapped = fr
+	return nil
+}
+
+// RemoveMapping implements memmap.Mappable.RemoveMapping.
+func (*Proc) RemoveMapping(context.Context, memmap.MappingSpace, usermem.AddrRange, uint64, bool) {
+	// Nothing to do. Notably, we don't free bp.mapped to allow another mmap.
+}
+
+// CopyMapping implements memmap.Mappable.CopyMapping.
+func (bp *Proc) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, _ bool) error {
+	// Nothing to do. Notably, this is one case where CopyMapping isn't
+	// equivalent to AddMapping, as AddMapping would return EBUSY.
+	return nil
+}
+
+// Translate implements memmap.Mappable.Translate.
+func (bp *Proc) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) {
+	// TODO(b/30946773): In addition to the page initially allocated and mapped
+	// in AddMapping (Linux: binder_mmap), Binder allocates and maps pages for
+	// each transaction (Linux: binder_ioctl => binder_ioctl_write_read =>
+	// binder_thread_write => binder_transaction => binder_alloc_buf =>
+	// binder_update_page_range). Since we don't actually implement
+	// BinderWriteReadIoctl (Linux: BINDER_WRITE_READ), we only ever have the
+	// first page.
+	var err error
+	if required.End > usermem.PageSize {
+		err = &memmap.BusError{syserror.EFAULT}
+	}
+	if required.Start == 0 {
+		return []memmap.Translation{
+			{
+				Source: memmap.MappableRange{0, usermem.PageSize},
+				File:   bp.mfp.MemoryFile(),
+				Offset: bp.mapped.Start,
+				Perms:  usermem.AnyAccess,
+			},
+		}, err
+	}
+	return nil, err
+}
+
+// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
+func (bp *Proc) InvalidateUnsavable(ctx context.Context) error {
+	return nil
+}
diff --git a/pkg/sentry/fs/binder/binder_state_autogen.go b/pkg/sentry/fs/binder/binder_state_autogen.go
new file mode 100755
index 000000000..195d9e00b
--- /dev/null
+++ b/pkg/sentry/fs/binder/binder_state_autogen.go
@@ -0,0 +1,40 @@
+// automatically generated by stateify.
+
+package binder
+
+import (
+	"gvisor.googlesource.com/gvisor/pkg/state"
+)
+
+func (x *Device) beforeSave() {}
+func (x *Device) save(m state.Map) {
+	x.beforeSave()
+	m.Save("InodeSimpleAttributes", &x.InodeSimpleAttributes)
+}
+
+func (x *Device) afterLoad() {}
+func (x *Device) load(m state.Map) {
+	m.Load("InodeSimpleAttributes", &x.InodeSimpleAttributes)
+}
+
+func (x *Proc) beforeSave() {}
+func (x *Proc) save(m state.Map) {
+	x.beforeSave()
+	m.Save("bd", &x.bd)
+	m.Save("task", &x.task)
+	m.Save("mfp", &x.mfp)
+	m.Save("mapped", &x.mapped)
+}
+
+func (x *Proc) afterLoad() {}
+func (x *Proc) load(m state.Map) {
+	m.Load("bd", &x.bd)
+	m.Load("task", &x.task)
+	m.Load("mfp", &x.mfp)
+	m.Load("mapped", &x.mapped)
+}
+
+func init() {
+	state.Register("binder.Device", (*Device)(nil), state.Fns{Save: (*Device).save, Load: (*Device).load})
+	state.Register("binder.Proc", (*Proc)(nil), state.Fns{Save: (*Proc).save, Load: (*Proc).load})
+}