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-rw-r--r--pkg/sentry/fsimpl/verity/verity.go120
-rw-r--r--pkg/sentry/fsimpl/verity/verity_test.go3
2 files changed, 100 insertions, 23 deletions
diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go
index 2f97324a8..6d6e0e77a 100644
--- a/pkg/sentry/fsimpl/verity/verity.go
+++ b/pkg/sentry/fsimpl/verity/verity.go
@@ -35,6 +35,7 @@ package verity
import (
"bytes"
+ "encoding/hex"
"encoding/json"
"fmt"
"math"
@@ -105,6 +106,13 @@ var (
verityMu sync.RWMutex
)
+// Mount option names for verityfs.
+const (
+ moptLowerPath = "lower_path"
+ moptRootHash = "root_hash"
+ moptRootName = "root_name"
+)
+
// HashAlgorithm is a type specifying the algorithm used to hash the file
// content.
type HashAlgorithm int
@@ -171,6 +179,9 @@ type filesystem struct {
// system.
alg HashAlgorithm
+ // opts is the string mount options passed to opts.Data.
+ opts string
+
// renameMu synchronizes renaming with non-renaming operations in order
// to ensure consistent lock ordering between dentry.dirMu in different
// dentries.
@@ -193,9 +204,6 @@ type filesystem struct {
//
// +stateify savable
type InternalFilesystemOptions struct {
- // RootMerkleFileName is the name of the verity root Merkle tree file.
- RootMerkleFileName string
-
// LowerName is the name of the filesystem wrapped by verity fs.
LowerName string
@@ -203,9 +211,6 @@ type InternalFilesystemOptions struct {
// system.
Alg HashAlgorithm
- // RootHash is the root hash of the overall verity file system.
- RootHash []byte
-
// AllowRuntimeEnable specifies whether the verity file system allows
// enabling verification for files (i.e. building Merkle trees) during
// runtime.
@@ -239,28 +244,99 @@ func alertIntegrityViolation(msg string) error {
// GetFilesystem implements vfs.FilesystemType.GetFilesystem.
func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) {
+ mopts := vfs.GenericParseMountOptions(opts.Data)
+ var rootHash []byte
+ if encodedRootHash, ok := mopts[moptRootHash]; ok {
+ delete(mopts, moptRootHash)
+ hash, err := hex.DecodeString(encodedRootHash)
+ if err != nil {
+ ctx.Warningf("verity.FilesystemType.GetFilesystem: Failed to decode root hash: %v", err)
+ return nil, nil, syserror.EINVAL
+ }
+ rootHash = hash
+ }
+ var lowerPathname string
+ if path, ok := mopts[moptLowerPath]; ok {
+ delete(mopts, moptLowerPath)
+ lowerPathname = path
+ }
+ rootName := "root"
+ if root, ok := mopts[moptRootName]; ok {
+ delete(mopts, moptRootName)
+ rootName = root
+ }
+
+ // Check for unparsed options.
+ if len(mopts) != 0 {
+ ctx.Warningf("verity.FilesystemType.GetFilesystem: unknown options: %v", mopts)
+ return nil, nil, syserror.EINVAL
+ }
+
+ // Handle internal options.
iopts, ok := opts.InternalData.(InternalFilesystemOptions)
- if !ok {
+ if len(lowerPathname) == 0 && !ok {
ctx.Warningf("verity.FilesystemType.GetFilesystem: missing verity configs")
return nil, nil, syserror.EINVAL
}
+ if len(lowerPathname) != 0 {
+ if ok {
+ ctx.Warningf("verity.FilesystemType.GetFilesystem: unexpected verity configs with specified lower path")
+ return nil, nil, syserror.EINVAL
+ }
+ iopts = InternalFilesystemOptions{
+ AllowRuntimeEnable: len(rootHash) == 0,
+ Action: ErrorOnViolation,
+ }
+ }
action = iopts.Action
- // Mount the lower file system. The lower file system is wrapped inside
- // verity, and should not be exposed or connected.
- mopts := &vfs.MountOptions{
- GetFilesystemOptions: iopts.LowerGetFSOptions,
- InternalMount: true,
- }
- mnt, err := vfsObj.MountDisconnected(ctx, creds, "", iopts.LowerName, mopts)
- if err != nil {
- return nil, nil, err
+ var lowerMount *vfs.Mount
+ var mountedLowerVD vfs.VirtualDentry
+ // Use an existing mount if lowerPath is provided.
+ if len(lowerPathname) != 0 {
+ vfsroot := vfs.RootFromContext(ctx)
+ if vfsroot.Ok() {
+ defer vfsroot.DecRef(ctx)
+ }
+ lowerPath := fspath.Parse(lowerPathname)
+ if !lowerPath.Absolute {
+ ctx.Infof("verity.FilesystemType.GetFilesystem: lower_path %q must be absolute", lowerPathname)
+ return nil, nil, syserror.EINVAL
+ }
+ var err error
+ mountedLowerVD, err = vfsObj.GetDentryAt(ctx, creds, &vfs.PathOperation{
+ Root: vfsroot,
+ Start: vfsroot,
+ Path: lowerPath,
+ FollowFinalSymlink: true,
+ }, &vfs.GetDentryOptions{
+ CheckSearchable: true,
+ })
+ if err != nil {
+ ctx.Infof("verity.FilesystemType.GetFilesystem: failed to resolve lower_path %q: %v", lowerPathname, err)
+ return nil, nil, err
+ }
+ lowerMount = mountedLowerVD.Mount()
+ defer mountedLowerVD.DecRef(ctx)
+ } else {
+ // Mount the lower file system. The lower file system is wrapped inside
+ // verity, and should not be exposed or connected.
+ mountOpts := &vfs.MountOptions{
+ GetFilesystemOptions: iopts.LowerGetFSOptions,
+ InternalMount: true,
+ }
+ mnt, err := vfsObj.MountDisconnected(ctx, creds, "", iopts.LowerName, mountOpts)
+ if err != nil {
+ return nil, nil, err
+ }
+ lowerMount = mnt
}
fs := &filesystem{
creds: creds.Fork(),
alg: iopts.Alg,
- lowerMount: mnt,
+ lowerMount: lowerMount,
+ opts: opts.Data,
allowRuntimeEnable: iopts.AllowRuntimeEnable,
}
fs.vfsfs.Init(vfsObj, &fstype, fs)
@@ -268,11 +344,11 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
// Construct the root dentry.
d := fs.newDentry()
d.refs = 1
- lowerVD := vfs.MakeVirtualDentry(mnt, mnt.Root())
+ lowerVD := vfs.MakeVirtualDentry(lowerMount, lowerMount.Root())
lowerVD.IncRef()
d.lowerVD = lowerVD
- rootMerkleName := merkleRootPrefix + iopts.RootMerkleFileName
+ rootMerkleName := merkleRootPrefix + rootName
lowerMerkleVD, err := vfsObj.GetDentryAt(ctx, fs.creds, &vfs.PathOperation{
Root: lowerVD,
@@ -352,7 +428,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
d.mode = uint32(stat.Mode)
d.uid = stat.UID
d.gid = stat.GID
- d.hash = make([]byte, len(iopts.RootHash))
+ d.hash = make([]byte, len(rootHash))
d.childrenNames = make(map[string]struct{})
if !d.isDir() {
@@ -427,7 +503,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
}
d.hashMu.Lock()
- copy(d.hash, iopts.RootHash)
+ copy(d.hash, rootHash)
d.hashMu.Unlock()
d.vfsd.Init(d)
@@ -443,7 +519,7 @@ func (fs *filesystem) Release(ctx context.Context) {
// MountOptions implements vfs.FilesystemImpl.MountOptions.
func (fs *filesystem) MountOptions() string {
- return ""
+ return fs.opts
}
// dentry implements vfs.DentryImpl.
diff --git a/pkg/sentry/fsimpl/verity/verity_test.go b/pkg/sentry/fsimpl/verity/verity_test.go
index 57bd65202..5c78a0019 100644
--- a/pkg/sentry/fsimpl/verity/verity_test.go
+++ b/pkg/sentry/fsimpl/verity/verity_test.go
@@ -89,10 +89,11 @@ func newVerityRoot(t *testing.T, hashAlg HashAlgorithm) (*vfs.VirtualFilesystem,
AllowUserMount: true,
})
+ data := "root_name=" + rootMerkleFilename
mntns, err := vfsObj.NewMountNamespace(ctx, auth.CredentialsFromContext(ctx), "", "verity", &vfs.MountOptions{
GetFilesystemOptions: vfs.GetFilesystemOptions{
+ Data: data,
InternalData: InternalFilesystemOptions{
- RootMerkleFileName: rootMerkleFilename,
LowerName: "tmpfs",
Alg: hashAlg,
AllowRuntimeEnable: true,
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 10:55:46 +0000