Commit 5bf7a60b authored Sep 27, 2018 by Yonghong Song Committed by Daniel Borkmann Sep 28, 2018

bpf: permit CGROUP_DEVICE programs accessing helper bpf_get_current_cgroup_id()



Currently, helper bpf_get_current_cgroup_id() is not permitted
for CGROUP_DEVICE type of programs. If the helper is used
in such cases, the verifier will log the following error:

  0: (bf) r6 = r1
  1: (69) r7 = *(u16 *)(r6 +0)
  2: (85) call bpf_get_current_cgroup_id#80
  unknown func bpf_get_current_cgroup_id#80

The bpf_get_current_cgroup_id() is useful for CGROUP_DEVICE
type of programs in order to customize action based on cgroup id.
This patch added such a support.

Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 78e6e5c1

kernel/bpf/cgroup.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -677,6 +677,8 @@ cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
	return &bpf_get_current_uid_gid_proto;		return &bpf_get_current_uid_gid_proto;
	case BPF_FUNC_get_local_storage:		case BPF_FUNC_get_local_storage:
	return &bpf_get_local_storage_proto;		return &bpf_get_local_storage_proto;
			case BPF_FUNC_get_current_cgroup_id:
			return &bpf_get_current_cgroup_id_proto;
	case BPF_FUNC_trace_printk:		case BPF_FUNC_trace_printk:
	if (capable(CAP_SYS_ADMIN))		if (capable(CAP_SYS_ADMIN))
	return bpf_get_trace_printk_proto();		return bpf_get_trace_printk_proto();

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