diff options
-rwxr-xr-x | pkg/sentry/fsbridge/fsbridge_state_autogen.go | 10 | ||||
-rwxr-xr-x | pkg/sentry/fsbridge/vfs.go | 28 | ||||
-rwxr-xr-x | pkg/sentry/fsimpl/kernfs/filesystem.go | 36 | ||||
-rwxr-xr-x | pkg/sentry/fsimpl/kernfs/inode_impl_util.go | 5 | ||||
-rwxr-xr-x | pkg/sentry/fsimpl/kernfs/kernfs.go | 16 | ||||
-rwxr-xr-x | pkg/sentry/fsimpl/kernfs/symlink.go | 5 |
6 files changed, 71 insertions, 29 deletions
diff --git a/pkg/sentry/fsbridge/fsbridge_state_autogen.go b/pkg/sentry/fsbridge/fsbridge_state_autogen.go index 51b57d859..d370b2d47 100755 --- a/pkg/sentry/fsbridge/fsbridge_state_autogen.go +++ b/pkg/sentry/fsbridge/fsbridge_state_autogen.go @@ -32,14 +32,14 @@ func (x *fsLookup) load(m state.Map) { m.Load("workingDir", &x.workingDir) } -func (x *vfsFile) beforeSave() {} -func (x *vfsFile) save(m state.Map) { +func (x *VFSFile) beforeSave() {} +func (x *VFSFile) save(m state.Map) { x.beforeSave() m.Save("file", &x.file) } -func (x *vfsFile) afterLoad() {} -func (x *vfsFile) load(m state.Map) { +func (x *VFSFile) afterLoad() {} +func (x *VFSFile) load(m state.Map) { m.Load("file", &x.file) } @@ -61,6 +61,6 @@ func (x *vfsLookup) load(m state.Map) { func init() { state.Register("pkg/sentry/fsbridge.fsFile", (*fsFile)(nil), state.Fns{Save: (*fsFile).save, Load: (*fsFile).load}) state.Register("pkg/sentry/fsbridge.fsLookup", (*fsLookup)(nil), state.Fns{Save: (*fsLookup).save, Load: (*fsLookup).load}) - state.Register("pkg/sentry/fsbridge.vfsFile", (*vfsFile)(nil), state.Fns{Save: (*vfsFile).save, Load: (*vfsFile).load}) + state.Register("pkg/sentry/fsbridge.VFSFile", (*VFSFile)(nil), state.Fns{Save: (*VFSFile).save, Load: (*VFSFile).load}) state.Register("pkg/sentry/fsbridge.vfsLookup", (*vfsLookup)(nil), state.Fns{Save: (*vfsLookup).save, Load: (*vfsLookup).load}) } diff --git a/pkg/sentry/fsbridge/vfs.go b/pkg/sentry/fsbridge/vfs.go index 79b808359..89168220a 100755 --- a/pkg/sentry/fsbridge/vfs.go +++ b/pkg/sentry/fsbridge/vfs.go @@ -26,22 +26,22 @@ import ( "gvisor.dev/gvisor/pkg/usermem" ) -// fsFile implements File interface over vfs.FileDescription. +// VFSFile implements File interface over vfs.FileDescription. // // +stateify savable -type vfsFile struct { +type VFSFile struct { file *vfs.FileDescription } -var _ File = (*vfsFile)(nil) +var _ File = (*VFSFile)(nil) // NewVFSFile creates a new File over fs.File. func NewVFSFile(file *vfs.FileDescription) File { - return &vfsFile{file: file} + return &VFSFile{file: file} } // PathnameWithDeleted implements File. -func (f *vfsFile) PathnameWithDeleted(ctx context.Context) string { +func (f *VFSFile) PathnameWithDeleted(ctx context.Context) string { root := vfs.RootFromContext(ctx) defer root.DecRef() @@ -51,7 +51,7 @@ func (f *vfsFile) PathnameWithDeleted(ctx context.Context) string { } // ReadFull implements File. -func (f *vfsFile) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) { +func (f *VFSFile) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) { var total int64 for dst.NumBytes() > 0 { n, err := f.file.PRead(ctx, dst, offset+total, vfs.ReadOptions{}) @@ -67,12 +67,12 @@ func (f *vfsFile) ReadFull(ctx context.Context, dst usermem.IOSequence, offset i } // ConfigureMMap implements File. -func (f *vfsFile) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error { +func (f *VFSFile) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error { return f.file.ConfigureMMap(ctx, opts) } // Type implements File. -func (f *vfsFile) Type(ctx context.Context) (linux.FileMode, error) { +func (f *VFSFile) Type(ctx context.Context) (linux.FileMode, error) { stat, err := f.file.Stat(ctx, vfs.StatOptions{}) if err != nil { return 0, err @@ -81,15 +81,21 @@ func (f *vfsFile) Type(ctx context.Context) (linux.FileMode, error) { } // IncRef implements File. -func (f *vfsFile) IncRef() { +func (f *VFSFile) IncRef() { f.file.IncRef() } // DecRef implements File. -func (f *vfsFile) DecRef() { +func (f *VFSFile) DecRef() { f.file.DecRef() } +// FileDescription returns the FileDescription represented by f. It does not +// take an additional reference on the returned FileDescription. +func (f *VFSFile) FileDescription() *vfs.FileDescription { + return f.file +} + // fsLookup implements Lookup interface using fs.File. // // +stateify savable @@ -132,5 +138,5 @@ func (l *vfsLookup) OpenPath(ctx context.Context, pathname string, opts vfs.Open if err != nil { return nil, err } - return &vfsFile{file: fd}, nil + return &VFSFile{file: fd}, nil } diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go index 89f5da3d4..16a3c18ae 100755 --- a/pkg/sentry/fsimpl/kernfs/filesystem.go +++ b/pkg/sentry/fsimpl/kernfs/filesystem.go @@ -79,16 +79,22 @@ afterSymlink: } // Resolve any symlink at current path component. if rp.ShouldFollowSymlink() && next.isSymlink() { - // TODO: VFS2 needs something extra for /proc/[pid]/fd/ "magic symlinks". - target, err := next.inode.Readlink(ctx) + targetVD, targetPathname, err := next.inode.Getlink(ctx) if err != nil { return nil, err } - if err := rp.HandleSymlink(target); err != nil { - return nil, err + if targetVD.Ok() { + err := rp.HandleJump(targetVD) + targetVD.DecRef() + if err != nil { + return nil, err + } + } else { + if err := rp.HandleSymlink(targetPathname); err != nil { + return nil, err + } } goto afterSymlink - } rp.Advance() return &next.vfsd, nil @@ -470,19 +476,25 @@ afterTrailingSymlink: } childDentry := childVFSD.Impl().(*Dentry) childInode := childDentry.inode - if rp.ShouldFollowSymlink() { - if childDentry.isSymlink() { - target, err := childInode.Readlink(ctx) + if rp.ShouldFollowSymlink() && childDentry.isSymlink() { + targetVD, targetPathname, err := childInode.Getlink(ctx) + if err != nil { + return nil, err + } + if targetVD.Ok() { + err := rp.HandleJump(targetVD) + targetVD.DecRef() if err != nil { return nil, err } - if err := rp.HandleSymlink(target); err != nil { + } else { + if err := rp.HandleSymlink(targetPathname); err != nil { return nil, err } - // rp.Final() may no longer be true since we now need to resolve the - // symlink target. - goto afterTrailingSymlink } + // rp.Final() may no longer be true since we now need to resolve the + // symlink target. + goto afterTrailingSymlink } if err := childInode.CheckPermissions(ctx, rp.Credentials(), ats); err != nil { return nil, err diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go index 5c84b10c9..65f09af5d 100755 --- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go +++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go @@ -181,6 +181,11 @@ func (InodeNotSymlink) Readlink(context.Context) (string, error) { return "", syserror.EINVAL } +// Getlink implements Inode.Getlink. +func (InodeNotSymlink) Getlink(context.Context) (vfs.VirtualDentry, string, error) { + return vfs.VirtualDentry{}, "", syserror.EINVAL +} + // InodeAttrs partially implements the Inode interface, specifically the // inodeMetadata sub interface. InodeAttrs provides functionality related to // inode attributes. diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go index 2cefef020..ad76b9f64 100755 --- a/pkg/sentry/fsimpl/kernfs/kernfs.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs.go @@ -414,7 +414,21 @@ type inodeDynamicLookup interface { } type inodeSymlink interface { - // Readlink resolves the target of a symbolic link. If an inode is not a + // Readlink returns the target of a symbolic link. If an inode is not a // symlink, the implementation should return EINVAL. Readlink(ctx context.Context) (string, error) + + // Getlink returns the target of a symbolic link, as used by path + // resolution: + // + // - If the inode is a "magic link" (a link whose target is most accurately + // represented as a VirtualDentry), Getlink returns (ok VirtualDentry, "", + // nil). A reference is taken on the returned VirtualDentry. + // + // - If the inode is an ordinary symlink, Getlink returns (zero-value + // VirtualDentry, symlink target, nil). + // + // - If the inode is not a symlink, Getlink returns (zero-value + // VirtualDentry, "", EINVAL). + Getlink(ctx context.Context) (vfs.VirtualDentry, string, error) } diff --git a/pkg/sentry/fsimpl/kernfs/symlink.go b/pkg/sentry/fsimpl/kernfs/symlink.go index 5918d3309..018aa503c 100755 --- a/pkg/sentry/fsimpl/kernfs/symlink.go +++ b/pkg/sentry/fsimpl/kernfs/symlink.go @@ -55,6 +55,11 @@ func (s *StaticSymlink) Readlink(_ context.Context) (string, error) { return s.target, nil } +// Getlink implements Inode.Getlink. +func (s *StaticSymlink) Getlink(_ context.Context) (vfs.VirtualDentry, string, error) { + return vfs.VirtualDentry{}, s.target, nil +} + // SetStat implements Inode.SetStat not allowing inode attributes to be changed. func (*StaticSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error { return syserror.EPERM |