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-rw-r--r--pkg/sentry/fs/host/control.go6
-rwxr-xr-xpkg/sentry/fsimpl/host/control.go96
-rw-r--r--pkg/sentry/socket/control/control.go24
-rwxr-xr-xpkg/sentry/socket/control/control_vfs2.go131
-rwxr-xr-xpkg/sentry/syscalls/linux/vfs2/socket.go2
5 files changed, 252 insertions, 7 deletions
diff --git a/pkg/sentry/fs/host/control.go b/pkg/sentry/fs/host/control.go
index 52c0504b6..39299b7e4 100644
--- a/pkg/sentry/fs/host/control.go
+++ b/pkg/sentry/fs/host/control.go
@@ -23,6 +23,8 @@ import (
"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
)
+// LINT.IfChange
+
type scmRights struct {
fds []int
}
@@ -32,8 +34,6 @@ func newSCMRights(fds []int) control.SCMRights {
}
// Files implements control.SCMRights.Files.
-//
-// TODO(gvisor.dev/issue/2017): Port to VFS2.
func (c *scmRights) Files(ctx context.Context, max int) (control.RightsFiles, bool) {
n := max
var trunc bool
@@ -93,3 +93,5 @@ func fdsToFiles(ctx context.Context, fds []int) []*fs.File {
}
return files
}
+
+// LINT.ThenChange(../../fsimpl/host/control.go)
diff --git a/pkg/sentry/fsimpl/host/control.go b/pkg/sentry/fsimpl/host/control.go
new file mode 100755
index 000000000..b9082a20f
--- /dev/null
+++ b/pkg/sentry/fsimpl/host/control.go
@@ -0,0 +1,96 @@
+// 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 host
+
+import (
+ "syscall"
+
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+ "gvisor.dev/gvisor/pkg/sentry/socket/control"
+ "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+)
+
+type scmRights struct {
+ fds []int
+}
+
+func newSCMRights(fds []int) control.SCMRightsVFS2 {
+ return &scmRights{fds}
+}
+
+// Files implements control.SCMRights.Files.
+func (c *scmRights) Files(ctx context.Context, max int) (control.RightsFilesVFS2, bool) {
+ n := max
+ var trunc bool
+ if l := len(c.fds); n > l {
+ n = l
+ } else if n < l {
+ trunc = true
+ }
+
+ rf := control.RightsFilesVFS2(fdsToFiles(ctx, c.fds[:n]))
+
+ // Only consume converted FDs (fdsToFiles may convert fewer than n FDs).
+ c.fds = c.fds[len(rf):]
+ return rf, trunc
+}
+
+// Clone implements transport.RightsControlMessage.Clone.
+func (c *scmRights) Clone() transport.RightsControlMessage {
+ // Host rights never need to be cloned.
+ return nil
+}
+
+// Release implements transport.RightsControlMessage.Release.
+func (c *scmRights) Release() {
+ for _, fd := range c.fds {
+ syscall.Close(fd)
+ }
+ c.fds = nil
+}
+
+// If an error is encountered, only files created before the error will be
+// returned. This is what Linux does.
+func fdsToFiles(ctx context.Context, fds []int) []*vfs.FileDescription {
+ files := make([]*vfs.FileDescription, 0, len(fds))
+ for _, fd := range fds {
+ // Get flags. We do it here because they may be modified
+ // by subsequent functions.
+ fileFlags, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_GETFL, 0)
+ if errno != 0 {
+ ctx.Warningf("Error retrieving host FD flags: %v", error(errno))
+ break
+ }
+
+ // Create the file backed by hostFD.
+ file, err := ImportFD(ctx, kernel.KernelFromContext(ctx).HostMount(), fd, false /* isTTY */)
+ if err != nil {
+ ctx.Warningf("Error creating file from host FD: %v", err)
+ break
+ }
+
+ if err := file.SetStatusFlags(ctx, auth.CredentialsFromContext(ctx), uint32(fileFlags&linux.O_NONBLOCK)); err != nil {
+ ctx.Warningf("Error setting flags on host FD file: %v", err)
+ break
+ }
+
+ files = append(files, file)
+ }
+ return files
+}
diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go
index 8834a1e1a..8b439a078 100644
--- a/pkg/sentry/socket/control/control.go
+++ b/pkg/sentry/socket/control/control.go
@@ -41,6 +41,8 @@ type SCMCredentials interface {
Credentials(t *kernel.Task) (kernel.ThreadID, auth.UID, auth.GID)
}
+// LINT.IfChange
+
// SCMRights represents a SCM_RIGHTS socket control message.
type SCMRights interface {
transport.RightsControlMessage
@@ -142,6 +144,8 @@ func PackRights(t *kernel.Task, rights SCMRights, cloexec bool, buf []byte, flag
return putCmsg(buf, flags, linux.SCM_RIGHTS, align, fds)
}
+// LINT.ThenChange(./control_vfs2.go)
+
// scmCredentials represents an SCM_CREDENTIALS socket control message.
//
// +stateify savable
@@ -537,11 +541,19 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
}
if len(fds) > 0 {
- rights, err := NewSCMRights(t, fds)
- if err != nil {
- return socket.ControlMessages{}, err
+ if kernel.VFS2Enabled {
+ rights, err := NewSCMRightsVFS2(t, fds)
+ if err != nil {
+ return socket.ControlMessages{}, err
+ }
+ cmsgs.Unix.Rights = rights
+ } else {
+ rights, err := NewSCMRights(t, fds)
+ if err != nil {
+ return socket.ControlMessages{}, err
+ }
+ cmsgs.Unix.Rights = rights
}
- cmsgs.Unix.Rights = rights
}
return cmsgs, nil
@@ -566,6 +578,8 @@ func MakeCreds(t *kernel.Task) SCMCredentials {
return &scmCredentials{t, tcred.EffectiveKUID, tcred.EffectiveKGID}
}
+// LINT.IfChange
+
// New creates default control messages if needed.
func New(t *kernel.Task, socketOrEndpoint interface{}, rights SCMRights) transport.ControlMessages {
return transport.ControlMessages{
@@ -573,3 +587,5 @@ func New(t *kernel.Task, socketOrEndpoint interface{}, rights SCMRights) transpo
Rights: rights,
}
}
+
+// LINT.ThenChange(./control_vfs2.go)
diff --git a/pkg/sentry/socket/control/control_vfs2.go b/pkg/sentry/socket/control/control_vfs2.go
new file mode 100755
index 000000000..fd08179be
--- /dev/null
+++ b/pkg/sentry/socket/control/control_vfs2.go
@@ -0,0 +1,131 @@
+// 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 control
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/syserror"
+)
+
+// SCMRightsVFS2 represents a SCM_RIGHTS socket control message.
+type SCMRightsVFS2 interface {
+ transport.RightsControlMessage
+
+ // Files returns up to max RightsFiles.
+ //
+ // Returned files are consumed and ownership is transferred to the caller.
+ // Subsequent calls to Files will return the next files.
+ Files(ctx context.Context, max int) (rf RightsFilesVFS2, truncated bool)
+}
+
+// RightsFiles represents a SCM_RIGHTS socket control message. A reference is
+// maintained for each vfs.FileDescription and is release either when an FD is created or
+// when the Release method is called.
+type RightsFilesVFS2 []*vfs.FileDescription
+
+// NewSCMRightsVFS2 creates a new SCM_RIGHTS socket control message
+// representation using local sentry FDs.
+func NewSCMRightsVFS2(t *kernel.Task, fds []int32) (SCMRightsVFS2, error) {
+ files := make(RightsFilesVFS2, 0, len(fds))
+ for _, fd := range fds {
+ file := t.GetFileVFS2(fd)
+ if file == nil {
+ files.Release()
+ return nil, syserror.EBADF
+ }
+ files = append(files, file)
+ }
+ return &files, nil
+}
+
+// Files implements SCMRights.Files.
+func (fs *RightsFilesVFS2) Files(ctx context.Context, max int) (RightsFilesVFS2, bool) {
+ n := max
+ var trunc bool
+ if l := len(*fs); n > l {
+ n = l
+ } else if n < l {
+ trunc = true
+ }
+ rf := (*fs)[:n]
+ *fs = (*fs)[n:]
+ return rf, trunc
+}
+
+// Clone implements transport.RightsControlMessage.Clone.
+func (fs *RightsFilesVFS2) Clone() transport.RightsControlMessage {
+ nfs := append(RightsFilesVFS2(nil), *fs...)
+ for _, nf := range nfs {
+ nf.IncRef()
+ }
+ return &nfs
+}
+
+// Release implements transport.RightsControlMessage.Release.
+func (fs *RightsFilesVFS2) Release() {
+ for _, f := range *fs {
+ f.DecRef()
+ }
+ *fs = nil
+}
+
+// rightsFDsVFS2 gets up to the specified maximum number of FDs.
+func rightsFDsVFS2(t *kernel.Task, rights SCMRightsVFS2, cloexec bool, max int) ([]int32, bool) {
+ files, trunc := rights.Files(t, max)
+ fds := make([]int32, 0, len(files))
+ for i := 0; i < max && len(files) > 0; i++ {
+ fd, err := t.NewFDFromVFS2(0, files[0], kernel.FDFlags{
+ CloseOnExec: cloexec,
+ })
+ files[0].DecRef()
+ files = files[1:]
+ if err != nil {
+ t.Warningf("Error inserting FD: %v", err)
+ // This is what Linux does.
+ break
+ }
+
+ fds = append(fds, int32(fd))
+ }
+ return fds, trunc
+}
+
+// PackRightsVFS2 packs as many FDs as will fit into the unused capacity of buf.
+func PackRightsVFS2(t *kernel.Task, rights SCMRightsVFS2, cloexec bool, buf []byte, flags int) ([]byte, int) {
+ maxFDs := (cap(buf) - len(buf) - linux.SizeOfControlMessageHeader) / 4
+ // Linux does not return any FDs if none fit.
+ if maxFDs <= 0 {
+ flags |= linux.MSG_CTRUNC
+ return buf, flags
+ }
+ fds, trunc := rightsFDsVFS2(t, rights, cloexec, maxFDs)
+ if trunc {
+ flags |= linux.MSG_CTRUNC
+ }
+ align := t.Arch().Width()
+ return putCmsg(buf, flags, linux.SCM_RIGHTS, align, fds)
+}
+
+// NewVFS2 creates default control messages if needed.
+func NewVFS2(t *kernel.Task, socketOrEndpoint interface{}, rights SCMRightsVFS2) transport.ControlMessages {
+ return transport.ControlMessages{
+ Credentials: makeCreds(t, socketOrEndpoint),
+ Rights: rights,
+ }
+}
diff --git a/pkg/sentry/syscalls/linux/vfs2/socket.go b/pkg/sentry/syscalls/linux/vfs2/socket.go
index b1ede32f0..10b668477 100755
--- a/pkg/sentry/syscalls/linux/vfs2/socket.go
+++ b/pkg/sentry/syscalls/linux/vfs2/socket.go
@@ -804,7 +804,7 @@ func recvSingleMsg(t *kernel.Task, s socket.SocketVFS2, msgPtr usermem.Addr, fla
}
if cms.Unix.Rights != nil {
- controlData, mflags = control.PackRights(t, cms.Unix.Rights.(control.SCMRights), flags&linux.MSG_CMSG_CLOEXEC != 0, controlData, mflags)
+ controlData, mflags = control.PackRightsVFS2(t, cms.Unix.Rights.(control.SCMRightsVFS2), flags&linux.MSG_CMSG_CLOEXEC != 0, controlData, mflags)
}
// Copy the address to the caller.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-15 05:38:03 +0000