oci.WithPrivileged: set the current caps, not the known caps

This change is needed for running the latest containerd inside Docker
that is not aware of the recently added caps (BPF, PERFMON, CHECKPOINT_RESTORE).

Without this change, containerd inside Docker fails to run containers with
"apply caps: operation not permitted" error.

See kubernetes-sigs/kind 2058

NOTE: The caller process of this function is now assumed to be as
privileged as possible.

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

oci/spec_opts.go

@@ -38,7 +38,6 @@ import (
 	"github.com/opencontainers/runc/libcontainer/user"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
-	"github.com/syndtr/gocapability/capability"
 )
 
 // SpecOpts sets spec specific information to a newly generated OCI spec
@@ -776,29 +775,6 @@ func WithCapabilities(caps []string) SpecOpts {
 	}
 }
 
-// WithAllCapabilities sets all linux capabilities for the process
-var WithAllCapabilities = func(ctx context.Context, client Client, c *containers.Container, s *Spec) error {
-	return WithCapabilities(GetAllCapabilities())(ctx, client, c, s)
-}
-
-// GetAllCapabilities returns all caps up to CAP_LAST_CAP
-// or CAP_BLOCK_SUSPEND on RHEL6
-func GetAllCapabilities() []string {
-	last := capability.CAP_LAST_CAP
-	// hack for RHEL6 which has no /proc/sys/kernel/cap_last_cap
-	if last == capability.Cap(63) {
-		last = capability.CAP_BLOCK_SUSPEND
-	}
-	var caps []string
-	for _, cap := range capability.List() {
-		if cap > last {
-			continue
-		}
-		caps = append(caps, "CAP_"+strings.ToUpper(cap.String()))
-	}
-	return caps
-}
-
 func capsContain(caps []string, s string) bool {
 	for _, c := range caps {
 		if c == s {
@@ -1132,7 +1108,7 @@ func WithDefaultUnixDevices(_ context.Context, _ Client, _ *containers.Container
 
 // WithPrivileged sets up options for a privileged container
 var WithPrivileged = Compose(
-	WithAllCapabilities,
+	WithAllCurrentCapabilities,
 	WithMaskedPaths(nil),
 	WithReadonlyPaths(nil),
 	WithWriteableSysfs,