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Date: Wed, 26 Oct 2016 08:56:49 +0200
From: Mickaël Salaün <mic@...ikod.net>
To: linux-kernel@...r.kernel.org
Cc: Mickaël Salaün <mic@...ikod.net>,
Alexei Starovoitov <ast@...nel.org>,
Andy Lutomirski <luto@...capital.net>,
Daniel Borkmann <daniel@...earbox.net>,
Daniel Mack <daniel@...que.org>, David Drysdale <drysdale@...gle.com>,
"David S . Miller" <davem@...emloft.net>,
"Eric W . Biederman" <ebiederm@...ssion.com>,
James Morris <james.l.morris@...cle.com>, Jann Horn <jann@...jh.net>,
Kees Cook <keescook@...omium.org>, Paul Moore <pmoore@...hat.com>,
Sargun Dhillon <sargun@...gun.me>,
"Serge E . Hallyn" <serge@...lyn.com>, Tejun Heo <tj@...nel.org>,
Thomas Graf <tgraf@...g.ch>, Will Drewry <wad@...omium.org>,
kernel-hardening@...ts.openwall.com, linux-api@...r.kernel.org,
linux-security-module@...r.kernel.org, netdev@...r.kernel.org,
cgroups@...r.kernel.org
Subject: [RFC v4 13/18] bpf/cgroup: Replace struct bpf_prog with struct bpf_object
This allows CONFIG_CGROUP_BPF to manage different type of pointers
instead of only eBPF programs. This will be useful for the next commits
to support Landlock with cgroups.
Changes since v3:
* do not use an union of pointers but a struct (suggested by Kees Cook)
Signed-off-by: Mickaël Salaün <mic@...ikod.net>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Daniel Mack <daniel@...que.org>
Cc: David S. Miller <davem@...emloft.net>
Cc: Tejun Heo <tj@...nel.org>
Link: https://lkml.kernel.org/r/CAGXu5j+F80XCPSVL0VxAAoTiYk5D1NKKC3jyAU=Z0Gi7L9S0aw@mail.gmail.com
---
include/linux/bpf-cgroup.h | 8 ++++++--
kernel/bpf/cgroup.c | 35 ++++++++++++++++++-----------------
2 files changed, 24 insertions(+), 19 deletions(-)
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index fc076de74ab9..2f608e5d94e9 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -14,14 +14,18 @@ struct sk_buff;
extern struct static_key_false cgroup_bpf_enabled_key;
#define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)
+struct bpf_object {
+ struct bpf_prog *prog;
+};
+
struct cgroup_bpf {
/*
* Store two sets of bpf_prog pointers, one for programs that are
* pinned directly to this cgroup, and one for those that are effective
* when this cgroup is accessed.
*/
- struct bpf_prog *prog[MAX_BPF_ATTACH_TYPE];
- struct bpf_prog *effective[MAX_BPF_ATTACH_TYPE];
+ struct bpf_object pinned[MAX_BPF_ATTACH_TYPE];
+ struct bpf_object effective[MAX_BPF_ATTACH_TYPE];
};
void cgroup_bpf_put(struct cgroup *cgrp);
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index a0ab43f264b0..75482cd92d56 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -20,18 +20,18 @@ DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);
EXPORT_SYMBOL(cgroup_bpf_enabled_key);
/**
- * cgroup_bpf_put() - put references of all bpf programs
+ * cgroup_bpf_put() - put references of all bpf objects
* @cgrp: the cgroup to modify
*/
void cgroup_bpf_put(struct cgroup *cgrp)
{
unsigned int type;
- for (type = 0; type < ARRAY_SIZE(cgrp->bpf.prog); type++) {
- struct bpf_prog *prog = cgrp->bpf.prog[type];
+ for (type = 0; type < ARRAY_SIZE(cgrp->bpf.pinned); type++) {
+ struct bpf_object pinned = cgrp->bpf.pinned[type];
- if (prog) {
- bpf_prog_put(prog);
+ if (pinned.prog) {
+ bpf_prog_put(pinned.prog);
static_branch_dec(&cgroup_bpf_enabled_key);
}
}
@@ -47,11 +47,12 @@ void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
unsigned int type;
for (type = 0; type < ARRAY_SIZE(cgrp->bpf.effective); type++) {
- struct bpf_prog *e;
+ struct bpf_prog *prog;
- e = rcu_dereference_protected(parent->bpf.effective[type],
- lockdep_is_held(&cgroup_mutex));
- rcu_assign_pointer(cgrp->bpf.effective[type], e);
+ prog = rcu_dereference_protected(
+ parent->bpf.effective[type].prog,
+ lockdep_is_held(&cgroup_mutex));
+ rcu_assign_pointer(cgrp->bpf.effective[type].prog, prog);
}
}
@@ -87,13 +88,13 @@ void __cgroup_bpf_update(struct cgroup *cgrp,
struct bpf_prog *prog,
enum bpf_attach_type type)
{
- struct bpf_prog *old_prog, *effective;
+ struct bpf_prog *old_prog = NULL, *effective_prog;
struct cgroup_subsys_state *pos;
- old_prog = xchg(cgrp->bpf.prog + type, prog);
+ old_prog = xchg(&cgrp->bpf.pinned[type].prog, prog);
- effective = (!prog && parent) ?
- rcu_dereference_protected(parent->bpf.effective[type],
+ effective_prog = (!prog && parent) ?
+ rcu_dereference_protected(parent->bpf.effective[type].prog,
lockdep_is_held(&cgroup_mutex)) :
prog;
@@ -101,11 +102,11 @@ void __cgroup_bpf_update(struct cgroup *cgrp,
struct cgroup *desc = container_of(pos, struct cgroup, self);
/* skip the subtree if the descendant has its own program */
- if (desc->bpf.prog[type] && desc != cgrp)
+ if (desc->bpf.pinned[type].prog && desc != cgrp)
pos = css_rightmost_descendant(pos);
else
- rcu_assign_pointer(desc->bpf.effective[type],
- effective);
+ rcu_assign_pointer(desc->bpf.effective[type].prog,
+ effective_prog);
}
if (prog)
@@ -151,7 +152,7 @@ int __cgroup_bpf_run_filter(struct sock *sk,
rcu_read_lock();
- prog = rcu_dereference(cgrp->bpf.effective[type]);
+ prog = rcu_dereference(cgrp->bpf.effective[type].prog);
if (prog) {
unsigned int offset = skb->data - skb_network_header(skb);
--
2.9.3
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