1 files changed, 46 insertions, 0 deletions

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 6b7500bbdb53..e88abc0865d5 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -384,6 +384,52 @@ cleanup:
         return err;
 }
 
+/* Must be called with cgroup_mutex held to avoid races. */
+int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+                       union bpf_attr __user *uattr)
+{
+        __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+        enum bpf_attach_type type = attr->query.attach_type;
+        struct list_head *progs = &cgrp->bpf.progs[type];
+        u32 flags = cgrp->bpf.flags[type];
+        int cnt, ret = 0, i;
+
+        if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE)
+                cnt = bpf_prog_array_length(cgrp->bpf.effective[type]);
+        else
+                cnt = prog_list_length(progs);
+
+        if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
+                return -EFAULT;
+        if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt)))
+                return -EFAULT;
+        if (attr->query.prog_cnt == 0 || !prog_ids || !cnt)
+                /* return early if user requested only program count + flags */
+                return 0;
+        if (attr->query.prog_cnt < cnt) {
+                cnt = attr->query.prog_cnt;
+                ret = -ENOSPC;
+        }
+
+        if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) {
+                return bpf_prog_array_copy_to_user(cgrp->bpf.effective[type],
+                                                   prog_ids, cnt);
+        } else {
+                struct bpf_prog_list *pl;
+                u32 id;
+
+                i = 0;
+                list_for_each_entry(pl, progs, node) {
+                        id = pl->prog->aux->id;
+                        if (copy_to_user(prog_ids + i, &id, sizeof(id)))
+                                return -EFAULT;
+                        if (++i == cnt)
+                                break;
+                }
+        }
+        return ret;
+}
+
 /**
  * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering
  * @sk: The socket sending or receiving traffic