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authorDavid S. Miller <davem@davemloft.net>2017-02-16 19:34:01 -0500
committerDavid S. Miller <davem@davemloft.net>2017-02-16 19:34:01 -0500
commit3f64116a838e6c3468f9d5eed7f1f87cf3a2c3eb (patch)
tree388024d2ddbdcb9991ef4b472dfac31e425b807e /kernel/bpf
parentf3caf8618bce7e86c6f4f86785dd004c71b63a2d (diff)
parent4695daefba8df8a11fa0b0edd595eedae9ea59ae (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/cgroup.c59
-rw-r--r--kernel/bpf/syscall.c20
2 files changed, 61 insertions, 18 deletions
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index a515f7b007c6..da0f53690295 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -52,6 +52,7 @@ void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
e = rcu_dereference_protected(parent->bpf.effective[type],
lockdep_is_held(&cgroup_mutex));
rcu_assign_pointer(cgrp->bpf.effective[type], e);
+ cgrp->bpf.disallow_override[type] = parent->bpf.disallow_override[type];
}
}
@@ -82,30 +83,63 @@ void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
*
* Must be called with cgroup_mutex held.
*/
-void __cgroup_bpf_update(struct cgroup *cgrp,
- struct cgroup *parent,
- struct bpf_prog *prog,
- enum bpf_attach_type type)
+int __cgroup_bpf_update(struct cgroup *cgrp, struct cgroup *parent,
+ struct bpf_prog *prog, enum bpf_attach_type type,
+ bool new_overridable)
{
- struct bpf_prog *old_prog, *effective;
+ struct bpf_prog *old_prog, *effective = NULL;
struct cgroup_subsys_state *pos;
+ bool overridable = true;
- old_prog = xchg(cgrp->bpf.prog + type, prog);
+ if (parent) {
+ overridable = !parent->bpf.disallow_override[type];
+ effective = rcu_dereference_protected(parent->bpf.effective[type],
+ lockdep_is_held(&cgroup_mutex));
+ }
+
+ if (prog && effective && !overridable)
+ /* if parent has non-overridable prog attached, disallow
+ * attaching new programs to descendent cgroup
+ */
+ return -EPERM;
+
+ if (prog && effective && overridable != new_overridable)
+ /* if parent has overridable prog attached, only
+ * allow overridable programs in descendent cgroup
+ */
+ return -EPERM;
- effective = (!prog && parent) ?
- rcu_dereference_protected(parent->bpf.effective[type],
- lockdep_is_held(&cgroup_mutex)) :
- prog;
+ old_prog = cgrp->bpf.prog[type];
+
+ if (prog) {
+ overridable = new_overridable;
+ effective = prog;
+ if (old_prog &&
+ cgrp->bpf.disallow_override[type] == new_overridable)
+ /* disallow attaching non-overridable on top
+ * of existing overridable in this cgroup
+ * and vice versa
+ */
+ return -EPERM;
+ }
+
+ if (!prog && !old_prog)
+ /* report error when trying to detach and nothing is attached */
+ return -ENOENT;
+
+ cgrp->bpf.prog[type] = 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.prog[type] && desc != cgrp) {
pos = css_rightmost_descendant(pos);
- else
+ } else {
rcu_assign_pointer(desc->bpf.effective[type],
effective);
+ desc->bpf.disallow_override[type] = !overridable;
+ }
}
if (prog)
@@ -115,6 +149,7 @@ void __cgroup_bpf_update(struct cgroup *cgrp,
bpf_prog_put(old_prog);
static_branch_dec(&cgroup_bpf_enabled_key);
}
+ return 0;
}
/**
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 08a4d287226b..f74ca17af64a 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -935,13 +935,14 @@ static int bpf_obj_get(const union bpf_attr *attr)
#ifdef CONFIG_CGROUP_BPF
-#define BPF_PROG_ATTACH_LAST_FIELD attach_type
+#define BPF_PROG_ATTACH_LAST_FIELD attach_flags
static int bpf_prog_attach(const union bpf_attr *attr)
{
+ enum bpf_prog_type ptype;
struct bpf_prog *prog;
struct cgroup *cgrp;
- enum bpf_prog_type ptype;
+ int ret;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
@@ -949,6 +950,9 @@ static int bpf_prog_attach(const union bpf_attr *attr)
if (CHECK_ATTR(BPF_PROG_ATTACH))
return -EINVAL;
+ if (attr->attach_flags & ~BPF_F_ALLOW_OVERRIDE)
+ return -EINVAL;
+
switch (attr->attach_type) {
case BPF_CGROUP_INET_INGRESS:
case BPF_CGROUP_INET_EGRESS:
@@ -971,10 +975,13 @@ static int bpf_prog_attach(const union bpf_attr *attr)
return PTR_ERR(cgrp);
}
- cgroup_bpf_update(cgrp, prog, attr->attach_type);
+ ret = cgroup_bpf_update(cgrp, prog, attr->attach_type,
+ attr->attach_flags & BPF_F_ALLOW_OVERRIDE);
+ if (ret)
+ bpf_prog_put(prog);
cgroup_put(cgrp);
- return 0;
+ return ret;
}
#define BPF_PROG_DETACH_LAST_FIELD attach_type
@@ -982,6 +989,7 @@ static int bpf_prog_attach(const union bpf_attr *attr)
static int bpf_prog_detach(const union bpf_attr *attr)
{
struct cgroup *cgrp;
+ int ret;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
@@ -997,7 +1005,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
if (IS_ERR(cgrp))
return PTR_ERR(cgrp);
- cgroup_bpf_update(cgrp, NULL, attr->attach_type);
+ ret = cgroup_bpf_update(cgrp, NULL, attr->attach_type, false);
cgroup_put(cgrp);
break;
@@ -1005,7 +1013,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
return -EINVAL;
}
- return 0;
+ return ret;
}
#endif /* CONFIG_CGROUP_BPF */