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From: "Mickaël Salaün" <mic@digikod.net>
To: linux-kernel@vger.kernel.org
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Andy Lutomirski" <luto@amacapital.net>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Casey Schaufler" <casey@schaufler-ca.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Daniel Mack" <daniel@zonque.org>,
	"David Drysdale" <drysdale@google.com>,
	"David S . Miller" <davem@davemloft.net>,
	"Elena Reshetova" <elena.reshetova@intel.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	"James Morris" <james.l.morris@oracle.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Paul Moore" <pmoore@redhat.com>,
	"Sargun Dhillon" <sargun@sargun.me>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	"Tejun Heo" <tj@kernel.org>, "Will Drewry" <wad@chromium.org>,
	kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
	linux-security-module@vger.kernel.org, netdev@vger.kernel.org,
	cgroups@vger.kernel.org
Subject: [RFC v3 13/22] bpf/cgroup: Replace struct bpf_prog with union bpf_object
Date: Wed, 14 Sep 2016 09:24:06 +0200
Message-ID: <20160914072415.26021-14-mic@digikod.net> (raw)
In-Reply-To: <20160914072415.26021-1-mic@digikod.net>

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.

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Daniel Mack <daniel@zonque.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Tejun Heo <tj@kernel.org>
---
 include/linux/bpf-cgroup.h |  8 ++++++--
 kernel/bpf/cgroup.c        | 44 +++++++++++++++++++++++---------------------
 2 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index fc076de74ab9..2234042d7f61 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)
 
+union 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];
+	union bpf_object pinned[MAX_BPF_ATTACH_TYPE];
+	union 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 21d168c3ad35..782878ec4f2d 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++) {
+		union 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;
+		union bpf_object e;
 
-		e = rcu_dereference_protected(parent->bpf.effective[type],
-					      lockdep_is_held(&cgroup_mutex));
-		rcu_assign_pointer(cgrp->bpf.effective[type], e);
+		e.prog = rcu_dereference_protected(
+				parent->bpf.effective[type].prog,
+				lockdep_is_held(&cgroup_mutex));
+		rcu_assign_pointer(cgrp->bpf.effective[type].prog, e.prog);
 	}
 }
 
@@ -87,32 +88,33 @@ void __cgroup_bpf_update(struct cgroup *cgrp,
 			 struct bpf_prog *prog,
 			 enum bpf_attach_type type)
 {
-	struct bpf_prog *old_prog, *effective;
+	union bpf_object obj, old_pinned, effective;
 	struct cgroup_subsys_state *pos;
 
-	old_prog = xchg(cgrp->bpf.prog + type, prog);
+	obj.prog = prog;
+	old_pinned = xchg(cgrp->bpf.pinned + type, obj);
 
-	effective = (!prog && parent) ?
-		rcu_dereference_protected(parent->bpf.effective[type],
+	effective.prog = (!obj.prog && parent) ?
+		rcu_dereference_protected(parent->bpf.effective[type].prog,
 					  lockdep_is_held(&cgroup_mutex)) :
-		prog;
+		obj.prog;
 
 	css_for_each_descendant_pre(pos, &cgrp->self) {
 		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)
+	if (obj.prog)
 		static_branch_inc(&cgroup_bpf_enabled_key);
 
-	if (old_prog) {
-		bpf_prog_put(old_prog);
+	if (old_pinned.prog) {
+		bpf_prog_put(old_pinned.prog);
 		static_branch_dec(&cgroup_bpf_enabled_key);
 	}
 }
@@ -151,7 +153,7 @@ 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_mac_header(skb);
 
-- 
2.9.3

  parent reply index

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-14  7:23 [RFC v3 00/22] Landlock LSM: Unprivileged sandboxing Mickaël Salaün
2016-09-14  7:23 ` [RFC v3 01/22] landlock: Add Kconfig Mickaël Salaün
2016-09-14  7:23 ` [RFC v3 02/22] bpf: Move u64_to_ptr() to BPF headers and inline it Mickaël Salaün
2016-09-14  7:23 ` [RFC v3 03/22] bpf,landlock: Add a new arraymap type to deal with (Landlock) handles Mickaël Salaün
2016-09-14 18:51   ` Alexei Starovoitov
2016-09-14 23:22     ` Mickaël Salaün
2016-09-14 23:28       ` Alexei Starovoitov
2016-09-15 21:51         ` Mickaël Salaün
2016-10-03 23:53   ` Kees Cook
2016-10-05 22:02     ` Mickaël Salaün
2016-09-14  7:23 ` [RFC v3 04/22] bpf: Set register type according to is_valid_access() Mickaël Salaün
2016-10-19 14:54   ` Thomas Graf
2016-10-19 15:10     ` Daniel Borkmann
2016-09-14  7:23 ` [RFC v3 05/22] bpf,landlock: Add eBPF program subtype and is_valid_subtype() verifier Mickaël Salaün
2016-10-19 15:01   ` Thomas Graf
2016-09-14  7:23 ` [RFC v3 06/22] landlock: Add LSM hooks Mickaël Salaün
2016-10-19 15:19   ` Thomas Graf
2016-10-19 22:42     ` Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 07/22] landlock: Handle file comparisons Mickaël Salaün
2016-09-14 19:07   ` Jann Horn
2016-09-14 22:39     ` Mickaël Salaün
2016-09-14 21:06   ` Alexei Starovoitov
2016-09-14 23:02     ` Mickaël Salaün
2016-09-14 23:24       ` Alexei Starovoitov
2016-09-15 21:25         ` Mickaël Salaün
2016-09-20  0:12           ` lsm naming dilemma. " Alexei Starovoitov
2016-09-20  1:10             ` Sargun Dhillon
2016-09-20 16:58               ` Mickaël Salaün
2016-10-03 23:30   ` Kees Cook
2016-09-14  7:24 ` [RFC v3 08/22] seccomp: Fix documentation for struct seccomp_filter Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 09/22] seccomp: Move struct seccomp_filter in seccomp.h Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 10/22] seccomp: Split put_seccomp_filter() with put_seccomp() Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 11/22] seccomp,landlock: Handle Landlock hooks per process hierarchy Mickaël Salaün
2016-09-14 18:43   ` Andy Lutomirski
2016-09-14 22:34     ` Mickaël Salaün
2016-10-03 23:52       ` Kees Cook
2016-10-05 21:05         ` Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 12/22] bpf: Cosmetic change for bpf_prog_attach() Mickaël Salaün
2016-09-14  7:24 ` Mickaël Salaün [this message]
2016-09-14  7:24 ` [RFC v3 14/22] bpf/cgroup: Make cgroup_bpf_update() return an error code Mickaël Salaün
2016-09-14 21:16   ` Alexei Starovoitov
2016-09-14  7:24 ` [RFC v3 15/22] bpf/cgroup: Move capability check Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 16/22] bpf/cgroup,landlock: Handle Landlock hooks per cgroup Mickaël Salaün
2016-10-03 23:43   ` Kees Cook
2016-10-05 20:58     ` Mickaël Salaün
2016-10-05 21:25       ` Kees Cook
2016-09-14  7:24 ` [RFC v3 17/22] cgroup: Add access check for cgroup_get_from_fd() Mickaël Salaün
2016-09-14 22:06   ` Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 18/22] cgroup,landlock: Add CGRP_NO_NEW_PRIVS to handle unprivileged hooks Mickaël Salaün
2016-09-14 18:27   ` Andy Lutomirski
2016-09-14 22:11     ` Mickaël Salaün
2016-09-15  1:25       ` Andy Lutomirski
2016-09-15  2:19         ` Alexei Starovoitov
2016-09-15  2:27           ` Andy Lutomirski
2016-09-15  4:00             ` Alexei Starovoitov
2016-09-15  4:08               ` Andy Lutomirski
2016-09-15  4:31                 ` Alexei Starovoitov
2016-09-15  4:38                   ` Andy Lutomirski
2016-09-15  4:48                     ` Alexei Starovoitov
2016-09-15 19:41                       ` Mickaël Salaün
2016-09-20  4:37                         ` Sargun Dhillon
2016-09-20 17:02                           ` Mickaël Salaün
2016-09-15 19:35         ` Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 19/22] landlock: Add interrupted origin Mickaël Salaün
2016-09-14 18:29   ` Andy Lutomirski
2016-09-14 22:14     ` Mickaël Salaün
2016-09-15  1:19       ` Andy Lutomirski
2016-10-03 23:46         ` Kees Cook
2016-10-05 21:01           ` Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 20/22] landlock: Add update and debug access flags Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 21/22] bpf,landlock: Add optional skb pointer in the Landlock context Mickaël Salaün
2016-09-14 21:20   ` Alexei Starovoitov
2016-09-14 22:46     ` Mickaël Salaün
2016-09-14  7:24 ` [RFC v3 22/22] samples/landlock: Add sandbox example Mickaël Salaün
2016-09-14 21:24   ` Alexei Starovoitov
2016-09-14 14:36 ` [RFC v3 00/22] Landlock LSM: Unprivileged sandboxing David Laight

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