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-rw-r--r--pkg/sentry/fs/dev/BUILD5
-rw-r--r--pkg/sentry/fs/dev/dev.go10
-rw-r--r--pkg/sentry/fs/dev/net_tun.go170
-rw-r--r--pkg/sentry/fs/mount_test.go11
-rw-r--r--pkg/sentry/fs/mounts.go10
-rw-r--r--pkg/sentry/fs/proc/mounts.go16
-rw-r--r--pkg/sentry/fs/proc/net.go5
-rw-r--r--pkg/sentry/fs/proc/sys_net.go4
8 files changed, 214 insertions, 17 deletions
diff --git a/pkg/sentry/fs/dev/BUILD b/pkg/sentry/fs/dev/BUILD
index 4c4b7d5cc..9b6bb26d0 100644
--- a/pkg/sentry/fs/dev/BUILD
+++ b/pkg/sentry/fs/dev/BUILD
@@ -9,6 +9,7 @@ go_library(
"device.go",
"fs.go",
"full.go",
+ "net_tun.go",
"null.go",
"random.go",
"tty.go",
@@ -19,15 +20,19 @@ go_library(
"//pkg/context",
"//pkg/rand",
"//pkg/safemem",
+ "//pkg/sentry/arch",
"//pkg/sentry/device",
"//pkg/sentry/fs",
"//pkg/sentry/fs/fsutil",
"//pkg/sentry/fs/ramfs",
"//pkg/sentry/fs/tmpfs",
+ "//pkg/sentry/kernel",
"//pkg/sentry/memmap",
"//pkg/sentry/mm",
"//pkg/sentry/pgalloc",
+ "//pkg/sentry/socket/netstack",
"//pkg/syserror",
+ "//pkg/tcpip/link/tun",
"//pkg/usermem",
"//pkg/waiter",
],
diff --git a/pkg/sentry/fs/dev/dev.go b/pkg/sentry/fs/dev/dev.go
index 35bd23991..7e66c29b0 100644
--- a/pkg/sentry/fs/dev/dev.go
+++ b/pkg/sentry/fs/dev/dev.go
@@ -66,8 +66,8 @@ func newMemDevice(ctx context.Context, iops fs.InodeOperations, msrc *fs.MountSo
})
}
-func newDirectory(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
- iops := ramfs.NewDir(ctx, nil, fs.RootOwner, fs.FilePermsFromMode(0555))
+func newDirectory(ctx context.Context, contents map[string]*fs.Inode, msrc *fs.MountSource) *fs.Inode {
+ iops := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555))
return fs.NewInode(ctx, iops, msrc, fs.StableAttr{
DeviceID: devDevice.DeviceID(),
InodeID: devDevice.NextIno(),
@@ -111,7 +111,7 @@ func New(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
// A devpts is typically mounted at /dev/pts to provide
// pseudoterminal support. Place an empty directory there for
// the devpts to be mounted over.
- "pts": newDirectory(ctx, msrc),
+ "pts": newDirectory(ctx, nil, msrc),
// Similarly, applications expect a ptmx device at /dev/ptmx
// connected to the terminals provided by /dev/pts/. Rather
// than creating a device directly (which requires a hairy
@@ -124,6 +124,10 @@ func New(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
"ptmx": newSymlink(ctx, "pts/ptmx", msrc),
"tty": newCharacterDevice(ctx, newTTYDevice(ctx, fs.RootOwner, 0666), msrc, ttyDevMajor, ttyDevMinor),
+
+ "net": newDirectory(ctx, map[string]*fs.Inode{
+ "tun": newCharacterDevice(ctx, newNetTunDevice(ctx, fs.RootOwner, 0666), msrc, netTunDevMajor, netTunDevMinor),
+ }, msrc),
}
iops := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555))
diff --git a/pkg/sentry/fs/dev/net_tun.go b/pkg/sentry/fs/dev/net_tun.go
new file mode 100644
index 000000000..755644488
--- /dev/null
+++ b/pkg/sentry/fs/dev/net_tun.go
@@ -0,0 +1,170 @@
+// 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 dev
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
+ "gvisor.dev/gvisor/pkg/sentry/fs"
+ "gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/socket/netstack"
+ "gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/tcpip/link/tun"
+ "gvisor.dev/gvisor/pkg/usermem"
+ "gvisor.dev/gvisor/pkg/waiter"
+)
+
+const (
+ netTunDevMajor = 10
+ netTunDevMinor = 200
+)
+
+// +stateify savable
+type netTunInodeOperations 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 = (*netTunInodeOperations)(nil)
+
+func newNetTunDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *netTunInodeOperations {
+ return &netTunInodeOperations{
+ InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC),
+ }
+}
+
+// GetFile implements fs.InodeOperations.GetFile.
+func (iops *netTunInodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
+ return fs.NewFile(ctx, d, flags, &netTunFileOperations{}), nil
+}
+
+// +stateify savable
+type netTunFileOperations struct {
+ fsutil.FileNoSeek `state:"nosave"`
+ fsutil.FileNoMMap `state:"nosave"`
+ fsutil.FileNoSplice `state:"nosave"`
+ fsutil.FileNoopFlush `state:"nosave"`
+ fsutil.FileNoopFsync `state:"nosave"`
+ fsutil.FileNotDirReaddir `state:"nosave"`
+ fsutil.FileUseInodeUnstableAttr `state:"nosave"`
+
+ device tun.Device
+}
+
+var _ fs.FileOperations = (*netTunFileOperations)(nil)
+
+// Release implements fs.FileOperations.Release.
+func (fops *netTunFileOperations) Release() {
+ fops.device.Release()
+}
+
+// Ioctl implements fs.FileOperations.Ioctl.
+func (fops *netTunFileOperations) Ioctl(ctx context.Context, file *fs.File, io usermem.IO, args arch.SyscallArguments) (uintptr, error) {
+ request := args[1].Uint()
+ data := args[2].Pointer()
+
+ switch request {
+ case linux.TUNSETIFF:
+ t := kernel.TaskFromContext(ctx)
+ if t == nil {
+ panic("Ioctl should be called from a task context")
+ }
+ if !t.HasCapability(linux.CAP_NET_ADMIN) {
+ return 0, syserror.EPERM
+ }
+ stack, ok := t.NetworkContext().(*netstack.Stack)
+ if !ok {
+ return 0, syserror.EINVAL
+ }
+
+ var req linux.IFReq
+ if _, err := usermem.CopyObjectIn(ctx, io, data, &req, usermem.IOOpts{
+ AddressSpaceActive: true,
+ }); err != nil {
+ return 0, err
+ }
+ flags := usermem.ByteOrder.Uint16(req.Data[:])
+ return 0, fops.device.SetIff(stack.Stack, req.Name(), flags)
+
+ case linux.TUNGETIFF:
+ var req linux.IFReq
+
+ copy(req.IFName[:], fops.device.Name())
+
+ // Linux adds IFF_NOFILTER (the same value as IFF_NO_PI unfortunately) when
+ // there is no sk_filter. See __tun_chr_ioctl() in net/drivers/tun.c.
+ flags := fops.device.Flags() | linux.IFF_NOFILTER
+ usermem.ByteOrder.PutUint16(req.Data[:], flags)
+
+ _, err := usermem.CopyObjectOut(ctx, io, data, &req, usermem.IOOpts{
+ AddressSpaceActive: true,
+ })
+ return 0, err
+
+ default:
+ return 0, syserror.ENOTTY
+ }
+}
+
+// Write implements fs.FileOperations.Write.
+func (fops *netTunFileOperations) Write(ctx context.Context, file *fs.File, src usermem.IOSequence, offset int64) (int64, error) {
+ data := make([]byte, src.NumBytes())
+ if _, err := src.CopyIn(ctx, data); err != nil {
+ return 0, err
+ }
+ return fops.device.Write(data)
+}
+
+// Read implements fs.FileOperations.Read.
+func (fops *netTunFileOperations) Read(ctx context.Context, file *fs.File, dst usermem.IOSequence, offset int64) (int64, error) {
+ data, err := fops.device.Read()
+ if err != nil {
+ return 0, err
+ }
+ n, err := dst.CopyOut(ctx, data)
+ if n > 0 && n < len(data) {
+ // Not an error for partial copying. Packet truncated.
+ err = nil
+ }
+ return int64(n), err
+}
+
+// Readiness implements watier.Waitable.Readiness.
+func (fops *netTunFileOperations) Readiness(mask waiter.EventMask) waiter.EventMask {
+ return fops.device.Readiness(mask)
+}
+
+// EventRegister implements watier.Waitable.EventRegister.
+func (fops *netTunFileOperations) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
+ fops.device.EventRegister(e, mask)
+}
+
+// EventUnregister implements watier.Waitable.EventUnregister.
+func (fops *netTunFileOperations) EventUnregister(e *waiter.Entry) {
+ fops.device.EventUnregister(e)
+}
diff --git a/pkg/sentry/fs/mount_test.go b/pkg/sentry/fs/mount_test.go
index e672a438c..a3d10770b 100644
--- a/pkg/sentry/fs/mount_test.go
+++ b/pkg/sentry/fs/mount_test.go
@@ -36,11 +36,12 @@ func mountPathsAre(root *Dirent, got []*Mount, want ...string) error {
gotPaths := make(map[string]struct{}, len(got))
gotStr := make([]string, len(got))
for i, g := range got {
- groot := g.Root()
- name, _ := groot.FullName(root)
- groot.DecRef()
- gotStr[i] = name
- gotPaths[name] = struct{}{}
+ if groot := g.Root(); groot != nil {
+ name, _ := groot.FullName(root)
+ groot.DecRef()
+ gotStr[i] = name
+ gotPaths[name] = struct{}{}
+ }
}
if len(got) != len(want) {
return fmt.Errorf("mount paths are different, got: %q, want: %q", gotStr, want)
diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go
index 574a2cc91..c7981f66e 100644
--- a/pkg/sentry/fs/mounts.go
+++ b/pkg/sentry/fs/mounts.go
@@ -100,10 +100,14 @@ func newUndoMount(d *Dirent) *Mount {
}
}
-// Root returns the root dirent of this mount. Callers must call DecRef on the
-// returned dirent.
+// Root returns the root dirent of this mount.
+//
+// This may return nil if the mount has already been free. Callers must handle this
+// case appropriately. If non-nil, callers must call DecRef on the returned *Dirent.
func (m *Mount) Root() *Dirent {
- m.root.IncRef()
+ if !m.root.TryIncRef() {
+ return nil
+ }
return m.root
}
diff --git a/pkg/sentry/fs/proc/mounts.go b/pkg/sentry/fs/proc/mounts.go
index c10888100..94deb553b 100644
--- a/pkg/sentry/fs/proc/mounts.go
+++ b/pkg/sentry/fs/proc/mounts.go
@@ -60,13 +60,15 @@ func forEachMount(t *kernel.Task, fn func(string, *fs.Mount)) {
})
for _, m := range ms {
mroot := m.Root()
+ if mroot == nil {
+ continue // No longer valid.
+ }
mountPath, desc := mroot.FullName(rootDir)
mroot.DecRef()
if !desc {
// MountSources that are not descendants of the chroot jail are ignored.
continue
}
-
fn(mountPath, m)
}
}
@@ -91,6 +93,12 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
var buf bytes.Buffer
forEachMount(mif.t, func(mountPath string, m *fs.Mount) {
+ mroot := m.Root()
+ if mroot == nil {
+ return // No longer valid.
+ }
+ defer mroot.DecRef()
+
// Format:
// 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
// (1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
@@ -107,9 +115,6 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
// (3) Major:Minor device ID. We don't have a superblock, so we
// just use the root inode device number.
- mroot := m.Root()
- defer mroot.DecRef()
-
sa := mroot.Inode.StableAttr
fmt.Fprintf(&buf, "%d:%d ", sa.DeviceFileMajor, sa.DeviceFileMinor)
@@ -207,6 +212,9 @@ func (mf *mountsFile) ReadSeqFileData(ctx context.Context, handle seqfile.SeqHan
//
// The "needs dump"and fsck flags are always 0, which is allowed.
root := m.Root()
+ if root == nil {
+ return // No longer valid.
+ }
defer root.DecRef()
flags := root.Inode.MountSource.Flags
diff --git a/pkg/sentry/fs/proc/net.go b/pkg/sentry/fs/proc/net.go
index 6f2775344..95d5817ff 100644
--- a/pkg/sentry/fs/proc/net.go
+++ b/pkg/sentry/fs/proc/net.go
@@ -43,7 +43,10 @@ import (
// newNet creates a new proc net entry.
func (p *proc) newNetDir(ctx context.Context, k *kernel.Kernel, msrc *fs.MountSource) *fs.Inode {
var contents map[string]*fs.Inode
- if s := p.k.NetworkStack(); s != nil {
+ // TODO(gvisor.dev/issue/1833): Support for using the network stack in the
+ // network namespace of the calling process. We should make this per-process,
+ // a.k.a. /proc/PID/net, and make /proc/net a symlink to /proc/self/net.
+ if s := p.k.RootNetworkNamespace().Stack(); s != nil {
contents = map[string]*fs.Inode{
"dev": seqfile.NewSeqFileInode(ctx, &netDev{s: s}, msrc),
"snmp": seqfile.NewSeqFileInode(ctx, &netSnmp{s: s}, msrc),
diff --git a/pkg/sentry/fs/proc/sys_net.go b/pkg/sentry/fs/proc/sys_net.go
index 0772d4ae4..d4c4b533d 100644
--- a/pkg/sentry/fs/proc/sys_net.go
+++ b/pkg/sentry/fs/proc/sys_net.go
@@ -357,7 +357,9 @@ func (p *proc) newSysNetIPv4Dir(ctx context.Context, msrc *fs.MountSource, s ine
func (p *proc) newSysNetDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
var contents map[string]*fs.Inode
- if s := p.k.NetworkStack(); s != nil {
+ // TODO(gvisor.dev/issue/1833): Support for using the network stack in the
+ // network namespace of the calling process.
+ if s := p.k.RootNetworkNamespace().Stack(); s != nil {
contents = map[string]*fs.Inode{
"ipv4": p.newSysNetIPv4Dir(ctx, msrc, s),
"core": p.newSysNetCore(ctx, msrc, s),
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 20:49:23 +0000