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Fix parent directory creation in CreateDeviceFile.

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It was not properly creating recursive directories. Added tests for this case.

Updates #1196

PiperOrigin-RevId: 327850811
This commit is contained in:
Nicolas Lacasse
2020-08-21 12:10:14 -07:00
committed by gVisor bot
parent c24db90be5
commit 2c422b7f21
3 changed files with 155 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/sentry/fsimpl/devtmpfs/BUILD
+1
View File
@@ -24,6 +24,7 @@ go_test(
library = ":devtmpfs",
deps = [
"//pkg/abi/linux",
"//pkg/context",
"//pkg/fspath",
"//pkg/sentry/contexttest",
"//pkg/sentry/fsimpl/tmpfs",
pkg/sentry/fsimpl/devtmpfs/devtmpfs.go
+6 -7
View File
@@ -18,6 +18,7 @@ package devtmpfs
import (
"fmt"
"path"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
@@ -150,13 +151,11 @@ func (a *Accessor) CreateDeviceFile(ctx context.Context, pathname string, kind v
// Create any parent directories. See
// devtmpfs.c:handle_create()=>path_create().
for it := fspath.Parse(pathname).Begin; it.NextOk(); it = it.Next() {
pop := a.pathOperationAt(it.String())
if err := a.vfsObj.MkdirAt(actx, a.creds, pop, &vfs.MkdirOptions{
Mode: 0755,
}); err != nil {
return fmt.Errorf("failed to create directory %q: %v", it.String(), err)
}
parent := path.Dir(pathname)
if err := a.vfsObj.MkdirAllAt(ctx, parent, a.root, a.creds, &vfs.MkdirOptions{
Mode: 0755,
}); err != nil {
return fmt.Errorf("failed to create device parent directory %q: %v", parent, err)
}
// NOTE: Linux's devtmpfs refuses to automatically delete files it didn't
pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go
+148 -41
View File
@@ -15,9 +15,11 @@
package devtmpfs
import (
"path"
"testing"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/sentry/contexttest"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs"
@@ -25,10 +27,13 @@ import (
"gvisor.dev/gvisor/pkg/sentry/vfs"
)
func TestDevtmpfs(t *testing.T) {
const devPath = "/dev"
func setupDevtmpfs(t *testing.T) (context.Context, *auth.Credentials, *vfs.VirtualFilesystem, vfs.VirtualDentry, func()) {
t.Helper()
ctx := contexttest.Context(t)
creds := auth.CredentialsFromContext(ctx)
vfsObj := &vfs.VirtualFilesystem{}
if err := vfsObj.Init(ctx); err != nil {
t.Fatalf("VFS init: %v", err)
@@ -43,14 +48,11 @@ func TestDevtmpfs(t *testing.T) {
})
// Create a test mount namespace with devtmpfs mounted at "/dev".
const devPath = "/dev"
mntns, err := vfsObj.NewMountNamespace(ctx, creds, "tmpfs" /* source */, "tmpfs" /* fsTypeName */, &vfs.GetFilesystemOptions{})
if err != nil {
t.Fatalf("failed to create tmpfs root mount: %v", err)
}
defer mntns.DecRef(ctx)
root := mntns.Root()
defer root.DecRef(ctx)
devpop := vfs.PathOperation{
Root: root,
Start: root,
@@ -65,6 +67,16 @@ func TestDevtmpfs(t *testing.T) {
t.Fatalf("failed to mount devtmpfs: %v", err)
}
return ctx, creds, vfsObj, root, func() {
root.DecRef(ctx)
mntns.DecRef(ctx)
}
}
func TestUserspaceInit(t *testing.T) {
ctx, creds, vfsObj, root, cleanup := setupDevtmpfs(t)
defer cleanup()
a, err := NewAccessor(ctx, vfsObj, creds, "devtmpfs")
if err != nil {
t.Fatalf("failed to create devtmpfs.Accessor: %v", err)
@@ -75,48 +87,143 @@ func TestDevtmpfs(t *testing.T) {
if err := a.UserspaceInit(ctx); err != nil {
t.Fatalf("failed to userspace-initialize devtmpfs: %v", err)
}
// Created files should be visible in the test mount namespace.
abspath := devPath + "/fd"
target, err := vfsObj.ReadlinkAt(ctx, creds, &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(abspath),
})
if want := "/proc/self/fd"; err != nil || target != want {
t.Fatalf("readlink(%q): got (%q, %v), wanted (%q, nil)", abspath, target, err, want)
links := []struct {
source string
target string
}{
{
source: "fd",
target: "/proc/self/fd",
},
{
source: "stdin",
target: "/proc/self/fd/0",
},
{
source: "stdout",
target: "/proc/self/fd/1",
},
{
source: "stderr",
target: "/proc/self/fd/2",
},
{
source: "ptmx",
target: "pts/ptmx",
},
}
// Create a dummy device special file using a devtmpfs.Accessor.
const (
pathInDev = "dummy"
kind = vfs.CharDevice
major = 12
minor = 34
perms = 0600
wantMode = linux.S_IFCHR | perms
)
if err := a.CreateDeviceFile(ctx, pathInDev, kind, major, minor, perms); err != nil {
t.Fatalf("failed to create device file: %v", err)
for _, link := range links {
abspath := path.Join(devPath, link.source)
if gotTarget, err := vfsObj.ReadlinkAt(ctx, creds, &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(abspath),
}); err != nil || gotTarget != link.target {
t.Errorf("readlink(%q): got (%q, %v), wanted (%q, nil)", abspath, gotTarget, err, link.target)
}
}
// The device special file should be visible in the test mount namespace.
abspath = devPath + "/" + pathInDev
stat, err := vfsObj.StatAt(ctx, creds, &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(abspath),
}, &vfs.StatOptions{
Mask: linux.STATX_TYPE | linux.STATX_MODE,
})
dirs := []string{"shm", "pts"}
for _, dir := range dirs {
abspath := path.Join(devPath, dir)
statx, err := vfsObj.StatAt(ctx, creds, &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(abspath),
}, &vfs.StatOptions{
Mask: linux.STATX_MODE,
})
if err != nil {
t.Errorf("stat(%q): got error %v ", abspath, err)
continue
}
if want := uint16(0755) | linux.S_IFDIR; statx.Mode != want {
t.Errorf("stat(%q): got mode %x, want %x", abspath, statx.Mode, want)
}
}
}
func TestCreateDeviceFile(t *testing.T) {
ctx, creds, vfsObj, root, cleanup := setupDevtmpfs(t)
defer cleanup()
a, err := NewAccessor(ctx, vfsObj, creds, "devtmpfs")
if err != nil {
t.Fatalf("failed to stat device file at %q: %v", abspath, err)
}
if stat.Mode != wantMode {
t.Errorf("device file mode: got %v, wanted %v", stat.Mode, wantMode)
t.Fatalf("failed to create devtmpfs.Accessor: %v", err)
}
if stat.RdevMajor != major {
t.Errorf("major device number: got %v, wanted %v", stat.RdevMajor, major)
defer a.Release(ctx)
devFiles := []struct {
path string
kind vfs.DeviceKind
major uint32
minor uint32
perms uint16
}{
{
path: "dummy",
kind: vfs.CharDevice,
major: 12,
minor: 34,
perms: 0600,
},
{
path: "foo/bar",
kind: vfs.BlockDevice,
major: 13,
minor: 35,
perms: 0660,
},
{
path: "foo/baz",
kind: vfs.CharDevice,
major: 12,
minor: 40,
perms: 0666,
},
{
path: "a/b/c/d/e",
kind: vfs.BlockDevice,
major: 12,
minor: 34,
perms: 0600,
},
}
if stat.RdevMinor != minor {
t.Errorf("minor device number: got %v, wanted %v", stat.RdevMinor, minor)
for _, f := range devFiles {
if err := a.CreateDeviceFile(ctx, f.path, f.kind, f.major, f.minor, f.perms); err != nil {
t.Fatalf("failed to create device file: %v", err)
}
// The device special file should be visible in the test mount namespace.
abspath := path.Join(devPath, f.path)
stat, err := vfsObj.StatAt(ctx, creds, &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(abspath),
}, &vfs.StatOptions{
Mask: linux.STATX_TYPE | linux.STATX_MODE,
})
if err != nil {
t.Fatalf("failed to stat device file at %q: %v", abspath, err)
}
if stat.RdevMajor != f.major {
t.Errorf("major device number: got %v, wanted %v", stat.RdevMajor, f.major)
}
if stat.RdevMinor != f.minor {
t.Errorf("minor device number: got %v, wanted %v", stat.RdevMinor, f.minor)
}
wantMode := f.perms
switch f.kind {
case vfs.CharDevice:
wantMode |= linux.S_IFCHR
case vfs.BlockDevice:
wantMode |= linux.S_IFBLK
}
if stat.Mode != wantMode {
t.Errorf("device file mode: got %v, wanted %v", stat.Mode, wantMode)
}
}
}