On Thu, Jun 16, 2022 at 5:58 PM Martin KaFai Lau <kafai@xxxxxx> wrote:
>
> On Fri, Jun 10, 2022 at 09:57:58AM -0700, Stanislav Fomichev wrote:
> > diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
> > index ba402d50e130..c869317479ec 100644
> > --- a/kernel/bpf/cgroup.c
> > +++ b/kernel/bpf/cgroup.c
> > @@ -1029,57 +1029,92 @@ static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
> > static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
> > union bpf_attr __user *uattr)
> > {
> > + __u32 __user *prog_attach_flags = u64_to_user_ptr(attr->query.prog_attach_flags);
> > __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
> > enum bpf_attach_type type = attr->query.attach_type;
> > + enum cgroup_bpf_attach_type from_atype, to_atype;
> > enum cgroup_bpf_attach_type atype;
> > struct bpf_prog_array *effective;
> > struct hlist_head *progs;
> > struct bpf_prog *prog;
> > int cnt, ret = 0, i;
> > + int total_cnt = 0;
> > u32 flags;
> >
> > - atype = to_cgroup_bpf_attach_type(type);
> > - if (atype < 0)
> > - return -EINVAL;
> > + if (type == BPF_LSM_CGROUP) {
> > + if (attr->query.prog_cnt && prog_ids && !prog_attach_flags)
> > + return -EINVAL;
> >
> > - progs = &cgrp->bpf.progs[atype];
> > - flags = cgrp->bpf.flags[atype];
> > + from_atype = CGROUP_LSM_START;
> > + to_atype = CGROUP_LSM_END;
> > + flags = 0;
> > + } else {
> > + from_atype = to_cgroup_bpf_attach_type(type);
> > + if (from_atype < 0)
> > + return -EINVAL;
> > + to_atype = from_atype;
> > + flags = cgrp->bpf.flags[from_atype];
> > + }
> >
> > - effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
> > - lockdep_is_held(&cgroup_mutex));
> > + for (atype = from_atype; atype <= to_atype; atype++) {
> > + progs = &cgrp->bpf.progs[atype];
> nit. Move the 'progs = ...' into the 'else {}' case below.
>
> >
> > - if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE)
> > - cnt = bpf_prog_array_length(effective);
> > - else
> > - cnt = prog_list_length(progs);
> > + if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) {
> > + effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
> > + lockdep_is_held(&cgroup_mutex));
> > + total_cnt += bpf_prog_array_length(effective);
> > + } else {
> > + total_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)))
> > + if (copy_to_user(&uattr->query.prog_cnt, &total_cnt, sizeof(total_cnt)))
> > return -EFAULT;
> > - if (attr->query.prog_cnt == 0 || !prog_ids || !cnt)
> > + if (attr->query.prog_cnt == 0 || !prog_ids || !total_cnt)
> > /* return early if user requested only program count + flags */
> > return 0;
> > - if (attr->query.prog_cnt < cnt) {
> > - cnt = attr->query.prog_cnt;
> > +
> > + if (attr->query.prog_cnt < total_cnt) {
> > + total_cnt = attr->query.prog_cnt;
> > ret = -ENOSPC;
> > }
> >
> > - if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) {
> > - return bpf_prog_array_copy_to_user(effective, prog_ids, cnt);
> > - } else {
> > - struct bpf_prog_list *pl;
> > - u32 id;
> > + for (atype = from_atype; atype <= to_atype && total_cnt; atype++) {
> > + progs = &cgrp->bpf.progs[atype];
> same here.
>
> > + flags = cgrp->bpf.flags[atype];
> and the 'flags = ...' can be moved to 'if (prog_attach_flags) {}'
>
> Others lgtm.
>
> Reviewed-by: Martin KaFai Lau <kafai@xxxxxx>
Everything makes sense, will do, thanks!
Maybe we should also move "struct hlist_head *progs;" closer to the
places where we use them? Same for "struct bpf_prog *prog;" which
seems to be used only in one place.
