diff options
| -rwxr-xr-x | pkg/sentry/fsbridge/vfs.go | 2 | ||||
| -rwxr-xr-x | pkg/sentry/vfs/mount.go | 42 | ||||
| -rwxr-xr-x | pkg/sentry/vfs/options.go | 16 | ||||
| -rwxr-xr-x | pkg/sentry/vfs/vfs.go | 5 | ||||
| -rwxr-xr-x | pkg/sentry/vfs/vfs_state_autogen.go | 2 |
5 files changed, 44 insertions, 23 deletions
diff --git a/pkg/sentry/fsbridge/vfs.go b/pkg/sentry/fsbridge/vfs.go index 6aa17bfc1..79b808359 100755 --- a/pkg/sentry/fsbridge/vfs.go +++ b/pkg/sentry/fsbridge/vfs.go @@ -115,8 +115,6 @@ func NewVFSLookup(mntns *vfs.MountNamespace, root, workingDir vfs.VirtualDentry) // // remainingTraversals is not configurable in VFS2, all callers are using the // default anyways. -// -// TODO(gvisor.dev/issue/1623): Check mount has read and exec permission. func (l *vfsLookup) OpenPath(ctx context.Context, pathname string, opts vfs.OpenOptions, _ *uint, resolveFinal bool) (File, error) { vfsObj := l.mntns.Root().Mount().Filesystem().VirtualFilesystem() creds := auth.CredentialsFromContext(ctx) diff --git a/pkg/sentry/vfs/mount.go b/pkg/sentry/vfs/mount.go index 31a4e5480..05f6233f9 100755 --- a/pkg/sentry/vfs/mount.go +++ b/pkg/sentry/vfs/mount.go @@ -74,6 +74,10 @@ type Mount struct { // umounted is true. umounted is protected by VirtualFilesystem.mountMu. umounted bool + // flags contains settings as specified for mount(2), e.g. MS_NOEXEC, except + // for MS_RDONLY which is tracked in "writers". + flags MountFlags + // The lower 63 bits of writers is the number of calls to // Mount.CheckBeginWrite() that have not yet been paired with a call to // Mount.EndWrite(). The MSB of writers is set if MS_RDONLY is in effect. @@ -81,6 +85,21 @@ type Mount struct { writers int64 } +func newMount(vfs *VirtualFilesystem, fs *Filesystem, root *Dentry, mntns *MountNamespace, opts *MountOptions) *Mount { + mnt := &Mount{ + vfs: vfs, + fs: fs, + root: root, + flags: opts.Flags, + ns: mntns, + refs: 1, + } + if opts.ReadOnly { + mnt.setReadOnlyLocked(true) + } + return mnt +} + // A MountNamespace is a collection of Mounts. // // MountNamespaces are reference-counted. Unless otherwise specified, all @@ -129,13 +148,7 @@ func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth refs: 1, mountpoints: make(map[*Dentry]uint32), } - mntns.root = &Mount{ - vfs: vfs, - fs: fs, - root: root, - ns: mntns, - refs: 1, - } + mntns.root = newMount(vfs, fs, root, mntns, &MountOptions{}) return mntns, nil } @@ -148,12 +161,7 @@ func (vfs *VirtualFilesystem) NewDisconnectedMount(fs *Filesystem, root *Dentry, if root != nil { root.IncRef() } - return &Mount{ - vfs: vfs, - fs: fs, - root: root, - refs: 1, - }, nil + return newMount(vfs, fs, root, nil /* mntns */, opts), nil } // MountAt creates and mounts a Filesystem configured by the given arguments. @@ -218,13 +226,7 @@ func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentia // are directories, or neither are, and returns ENOTDIR if this is not the // case. mntns := vd.mount.ns - mnt := &Mount{ - vfs: vfs, - fs: fs, - root: root, - ns: mntns, - refs: 1, - } + mnt := newMount(vfs, fs, root, mntns, opts) vfs.mounts.seq.BeginWrite() vfs.connectLocked(mnt, vd, mntns) vfs.mounts.seq.EndWrite() diff --git a/pkg/sentry/vfs/options.go b/pkg/sentry/vfs/options.go index 6af7fdac1..3e90dc4ed 100755 --- a/pkg/sentry/vfs/options.go +++ b/pkg/sentry/vfs/options.go @@ -46,8 +46,21 @@ type MknodOptions struct { DevMinor uint32 } +// MountFlags contains flags as specified for mount(2), e.g. MS_NOEXEC. +// MS_RDONLY is not part of MountFlags because it's tracked in Mount.writers. +type MountFlags struct { + // NoExec is equivalent to MS_NOEXEC. + NoExec bool +} + // MountOptions contains options to VirtualFilesystem.MountAt(). type MountOptions struct { + // Flags contains flags as specified for mount(2), e.g. MS_NOEXEC. + Flags MountFlags + + // ReadOnly is equivalent to MS_RDONLY. + ReadOnly bool + // GetFilesystemOptions contains options to FilesystemType.GetFilesystem(). GetFilesystemOptions GetFilesystemOptions @@ -75,7 +88,8 @@ type OpenOptions struct { // FileExec is set when the file is being opened to be executed. // VirtualFilesystem.OpenAt() checks that the caller has execute permissions - // on the file, and that the file is a regular file. + // on the file, that the file is a regular file, and that the mount doesn't + // have MS_NOEXEC set. FileExec bool } diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go index bde81e1ef..365e8b30d 100755 --- a/pkg/sentry/vfs/vfs.go +++ b/pkg/sentry/vfs/vfs.go @@ -388,6 +388,11 @@ func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credential // TODO(gvisor.dev/issue/1193): Move inside fsimpl to avoid another call // to FileDescription.Stat(). if opts.FileExec { + if fd.Mount().flags.NoExec { + fd.DecRef() + return nil, syserror.EACCES + } + // Only a regular file can be executed. stat, err := fd.Stat(ctx, StatOptions{Mask: linux.STATX_TYPE}) if err != nil { diff --git a/pkg/sentry/vfs/vfs_state_autogen.go b/pkg/sentry/vfs/vfs_state_autogen.go index 243646328..036defa97 100755 --- a/pkg/sentry/vfs/vfs_state_autogen.go +++ b/pkg/sentry/vfs/vfs_state_autogen.go @@ -119,6 +119,7 @@ func (x *Mount) save(m state.Map) { m.Save("refs", &x.refs) m.Save("children", &x.children) m.Save("umounted", &x.umounted) + m.Save("flags", &x.flags) m.Save("writers", &x.writers) } @@ -132,6 +133,7 @@ func (x *Mount) load(m state.Map) { m.Load("refs", &x.refs) m.Load("children", &x.children) m.Load("umounted", &x.umounted) + m.Load("flags", &x.flags) m.Load("writers", &x.writers) } |