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-rw-r--r--pkg/abi/linux/dev.go3
-rw-r--r--pkg/sentry/devices/memdev/BUILD28
-rw-r--r--pkg/sentry/devices/memdev/full.go75
-rw-r--r--pkg/sentry/devices/memdev/memdev.go59
-rw-r--r--pkg/sentry/devices/memdev/null.go76
-rw-r--r--pkg/sentry/devices/memdev/random.go92
-rw-r--r--pkg/sentry/devices/memdev/zero.go88
7 files changed, 421 insertions, 0 deletions
diff --git a/pkg/abi/linux/dev.go b/pkg/abi/linux/dev.go
index 421e11256..89f9a793f 100644
--- a/pkg/abi/linux/dev.go
+++ b/pkg/abi/linux/dev.go
@@ -36,6 +36,9 @@ func DecodeDeviceID(rdev uint32) (uint16, uint32) {
//
// See Documentations/devices.txt and uapi/linux/major.h.
const (
+ // MEM_MAJOR is the major device number for "memory" character devices.
+ MEM_MAJOR = 1
+
// TTYAUX_MAJOR is the major device number for alternate TTY devices.
TTYAUX_MAJOR = 5
diff --git a/pkg/sentry/devices/memdev/BUILD b/pkg/sentry/devices/memdev/BUILD
new file mode 100644
index 000000000..abe58f818
--- /dev/null
+++ b/pkg/sentry/devices/memdev/BUILD
@@ -0,0 +1,28 @@
+load("//tools:defs.bzl", "go_library")
+
+licenses(["notice"])
+
+go_library(
+ name = "memdev",
+ srcs = [
+ "full.go",
+ "memdev.go",
+ "null.go",
+ "random.go",
+ "zero.go",
+ ],
+ visibility = ["//pkg/sentry:internal"],
+ deps = [
+ "//pkg/abi/linux",
+ "//pkg/context",
+ "//pkg/rand",
+ "//pkg/safemem",
+ "//pkg/sentry/fsimpl/devtmpfs",
+ "//pkg/sentry/memmap",
+ "//pkg/sentry/mm",
+ "//pkg/sentry/pgalloc",
+ "//pkg/sentry/vfs",
+ "//pkg/syserror",
+ "//pkg/usermem",
+ ],
+)
diff --git a/pkg/sentry/devices/memdev/full.go b/pkg/sentry/devices/memdev/full.go
new file mode 100644
index 000000000..c7e197691
--- /dev/null
+++ b/pkg/sentry/devices/memdev/full.go
@@ -0,0 +1,75 @@
+// 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 memdev
+
+import (
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+const fullDevMinor = 7
+
+// fullDevice implements vfs.Device for /dev/full.
+type fullDevice struct{}
+
+// Open implements vfs.Device.Open.
+func (fullDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
+ fd := &fullFD{}
+ if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
+ UseDentryMetadata: true,
+ }); err != nil {
+ return nil, err
+ }
+ return &fd.vfsfd, nil
+}
+
+// fullFD implements vfs.FileDescriptionImpl for /dev/full.
+type fullFD struct {
+ vfsfd vfs.FileDescription
+ vfs.FileDescriptionDefaultImpl
+ vfs.DentryMetadataFileDescriptionImpl
+}
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (fd *fullFD) Release() {
+ // noop
+}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *fullFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+ return dst.ZeroOut(ctx, dst.NumBytes())
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *fullFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+ return dst.ZeroOut(ctx, dst.NumBytes())
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *fullFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+ return 0, syserror.ENOSPC
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *fullFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+ return 0, syserror.ENOSPC
+}
+
+// Seek implements vfs.FileDescriptionImpl.Seek.
+func (fd *fullFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+ return 0, nil
+}
diff --git a/pkg/sentry/devices/memdev/memdev.go b/pkg/sentry/devices/memdev/memdev.go
new file mode 100644
index 000000000..5759900c4
--- /dev/null
+++ b/pkg/sentry/devices/memdev/memdev.go
@@ -0,0 +1,59 @@
+// 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 memdev implements "mem" character devices, as implemented in Linux
+// by drivers/char/mem.c and drivers/char/random.c.
+package memdev
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/fsimpl/devtmpfs"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+)
+
+// Register registers all devices implemented by this package in vfsObj.
+func Register(vfsObj *vfs.VirtualFilesystem) error {
+ for minor, dev := range map[uint32]vfs.Device{
+ nullDevMinor: nullDevice{},
+ zeroDevMinor: zeroDevice{},
+ fullDevMinor: fullDevice{},
+ randomDevMinor: randomDevice{},
+ urandomDevMinor: randomDevice{},
+ } {
+ if err := vfsObj.RegisterDevice(vfs.CharDevice, linux.MEM_MAJOR, minor, dev, &vfs.RegisterDeviceOptions{
+ GroupName: "mem",
+ }); err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+// CreateDevtmpfsFiles creates device special files in dev representing all
+// devices implemented by this package.
+func CreateDevtmpfsFiles(ctx context.Context, dev *devtmpfs.Accessor) error {
+ for minor, name := range map[uint32]string{
+ nullDevMinor: "null",
+ zeroDevMinor: "zero",
+ fullDevMinor: "full",
+ randomDevMinor: "random",
+ urandomDevMinor: "urandom",
+ } {
+ if err := dev.CreateDeviceFile(ctx, name, vfs.CharDevice, linux.MEM_MAJOR, minor, 0666 /* mode */); err != nil {
+ return err
+ }
+ }
+ return nil
+}
diff --git a/pkg/sentry/devices/memdev/null.go b/pkg/sentry/devices/memdev/null.go
new file mode 100644
index 000000000..33d060d02
--- /dev/null
+++ b/pkg/sentry/devices/memdev/null.go
@@ -0,0 +1,76 @@
+// 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 memdev
+
+import (
+ "io"
+
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+const nullDevMinor = 3
+
+// nullDevice implements vfs.Device for /dev/null.
+type nullDevice struct{}
+
+// Open implements vfs.Device.Open.
+func (nullDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
+ fd := &nullFD{}
+ if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
+ UseDentryMetadata: true,
+ }); err != nil {
+ return nil, err
+ }
+ return &fd.vfsfd, nil
+}
+
+// nullFD implements vfs.FileDescriptionImpl for /dev/null.
+type nullFD struct {
+ vfsfd vfs.FileDescription
+ vfs.FileDescriptionDefaultImpl
+ vfs.DentryMetadataFileDescriptionImpl
+}
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (fd *nullFD) Release() {
+ // noop
+}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *nullFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+ return 0, io.EOF
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *nullFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+ return 0, io.EOF
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *nullFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+ return src.NumBytes(), nil
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *nullFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+ return src.NumBytes(), nil
+}
+
+// Seek implements vfs.FileDescriptionImpl.Seek.
+func (fd *nullFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+ return 0, nil
+}
diff --git a/pkg/sentry/devices/memdev/random.go b/pkg/sentry/devices/memdev/random.go
new file mode 100644
index 000000000..acfa23149
--- /dev/null
+++ b/pkg/sentry/devices/memdev/random.go
@@ -0,0 +1,92 @@
+// 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 memdev
+
+import (
+ "sync/atomic"
+
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/rand"
+ "gvisor.dev/gvisor/pkg/safemem"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+const (
+ randomDevMinor = 8
+ urandomDevMinor = 9
+)
+
+// randomDevice implements vfs.Device for /dev/random and /dev/urandom.
+type randomDevice struct{}
+
+// Open implements vfs.Device.Open.
+func (randomDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
+ fd := &randomFD{}
+ if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
+ UseDentryMetadata: true,
+ }); err != nil {
+ return nil, err
+ }
+ return &fd.vfsfd, nil
+}
+
+// randomFD implements vfs.FileDescriptionImpl for /dev/random.
+type randomFD struct {
+ vfsfd vfs.FileDescription
+ vfs.FileDescriptionDefaultImpl
+ vfs.DentryMetadataFileDescriptionImpl
+
+ // off is the "file offset". off is accessed using atomic memory
+ // operations.
+ off int64
+}
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (fd *randomFD) Release() {
+ // noop
+}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *randomFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+ return dst.CopyOutFrom(ctx, safemem.FromIOReader{rand.Reader})
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *randomFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+ n, err := dst.CopyOutFrom(ctx, safemem.FromIOReader{rand.Reader})
+ atomic.AddInt64(&fd.off, n)
+ return n, err
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *randomFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+ // In Linux, this mixes the written bytes into the entropy pool; we just
+ // throw them away.
+ return src.NumBytes(), nil
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *randomFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+ atomic.AddInt64(&fd.off, src.NumBytes())
+ return src.NumBytes(), nil
+}
+
+// Seek implements vfs.FileDescriptionImpl.Seek.
+func (fd *randomFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+ // Linux: drivers/char/random.c:random_fops.llseek == urandom_fops.llseek
+ // == noop_llseek
+ return atomic.LoadInt64(&fd.off), nil
+}
diff --git a/pkg/sentry/devices/memdev/zero.go b/pkg/sentry/devices/memdev/zero.go
new file mode 100644
index 000000000..3b1372b9e
--- /dev/null
+++ b/pkg/sentry/devices/memdev/zero.go
@@ -0,0 +1,88 @@
+// 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 memdev
+
+import (
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
+ "gvisor.dev/gvisor/pkg/sentry/mm"
+ "gvisor.dev/gvisor/pkg/sentry/pgalloc"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+const zeroDevMinor = 5
+
+// zeroDevice implements vfs.Device for /dev/zero.
+type zeroDevice struct{}
+
+// Open implements vfs.Device.Open.
+func (zeroDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
+ fd := &zeroFD{}
+ if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
+ UseDentryMetadata: true,
+ }); err != nil {
+ return nil, err
+ }
+ return &fd.vfsfd, nil
+}
+
+// zeroFD implements vfs.FileDescriptionImpl for /dev/zero.
+type zeroFD struct {
+ vfsfd vfs.FileDescription
+ vfs.FileDescriptionDefaultImpl
+ vfs.DentryMetadataFileDescriptionImpl
+}
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (fd *zeroFD) Release() {
+ // noop
+}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *zeroFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+ return dst.ZeroOut(ctx, dst.NumBytes())
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *zeroFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+ return dst.ZeroOut(ctx, dst.NumBytes())
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *zeroFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+ return src.NumBytes(), nil
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *zeroFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+ return src.NumBytes(), nil
+}
+
+// Seek implements vfs.FileDescriptionImpl.Seek.
+func (fd *zeroFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+ return 0, nil
+}
+
+// ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap.
+func (fd *zeroFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
+ m, err := mm.NewSharedAnonMappable(opts.Length, pgalloc.MemoryFileProviderFromContext(ctx))
+ if err != nil {
+ return err
+ }
+ opts.MappingIdentity = m
+ opts.Mappable = m
+ return nil
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 15:32:44 +0000