{
unsigned int type;
- for (type = 0; type < ARRAY_SIZE(cgrp->bpf.prog); type++) {
- struct bpf_prog *prog = cgrp->bpf.prog[type];
-
- if (prog) {
- bpf_prog_put(prog);
+ for (type = 0; type < ARRAY_SIZE(cgrp->bpf.progs); type++) {
+ struct list_head *progs = &cgrp->bpf.progs[type];
+ struct bpf_prog_list *pl, *tmp;
+
+ list_for_each_entry_safe(pl, tmp, progs, node) {
+ list_del(&pl->node);
+ bpf_prog_put(pl->prog);
+ kfree(pl);
static_branch_dec(&cgroup_bpf_enabled_key);
}
+ bpf_prog_array_free(cgrp->bpf.effective[type]);
+ }
+}
+
+/* count number of elements in the list.
+ * it's slow but the list cannot be long
+ */
+static u32 prog_list_length(struct list_head *head)
+{
+ struct bpf_prog_list *pl;
+ u32 cnt = 0;
+
+ list_for_each_entry(pl, head, node) {
+ if (!pl->prog)
+ continue;
+ cnt++;
}
+ return cnt;
+}
+
+/* if parent has non-overridable prog attached,
+ * disallow attaching new programs to the descendent cgroup.
+ * if parent has overridable or multi-prog, allow attaching
+ */
+static bool hierarchy_allows_attach(struct cgroup *cgrp,
+ enum bpf_attach_type type,
+ u32 new_flags)
+{
+ struct cgroup *p;
+
+ p = cgroup_parent(cgrp);
+ if (!p)
+ return true;
+ do {
+ u32 flags = p->bpf.flags[type];
+ u32 cnt;
+
+ if (flags & BPF_F_ALLOW_MULTI)
+ return true;
+ cnt = prog_list_length(&p->bpf.progs[type]);
+ WARN_ON_ONCE(cnt > 1);
+ if (cnt == 1)
+ return !!(flags & BPF_F_ALLOW_OVERRIDE);
+ p = cgroup_parent(p);
+ } while (p);
+ return true;
+}
+
+/* compute a chain of effective programs for a given cgroup:
+ * start from the list of programs in this cgroup and add
+ * all parent programs.
+ * Note that parent's F_ALLOW_OVERRIDE-type program is yielding
+ * to programs in this cgroup
+ */
+static int compute_effective_progs(struct cgroup *cgrp,
+ enum bpf_attach_type type,
+ struct bpf_prog_array __rcu **array)
+{
+ struct bpf_prog_array __rcu *progs;
+ struct bpf_prog_list *pl;
+ struct cgroup *p = cgrp;
+ int cnt = 0;
+
+ /* count number of effective programs by walking parents */
+ do {
+ if (cnt == 0 || (p->bpf.flags[type] & BPF_F_ALLOW_MULTI))
+ cnt += prog_list_length(&p->bpf.progs[type]);
+ p = cgroup_parent(p);
+ } while (p);
+
+ progs = bpf_prog_array_alloc(cnt, GFP_KERNEL);
+ if (!progs)
+ return -ENOMEM;
+
+ /* populate the array with effective progs */
+ cnt = 0;
+ p = cgrp;
+ do {
+ if (cnt == 0 || (p->bpf.flags[type] & BPF_F_ALLOW_MULTI))
+ list_for_each_entry(pl,
+ &p->bpf.progs[type], node) {
+ if (!pl->prog)
+ continue;
+ rcu_dereference_protected(progs, 1)->
+ progs[cnt++] = pl->prog;
+ }
+ p = cgroup_parent(p);
+ } while (p);
+
+ *array = progs;
+ return 0;
+}
+
+static void activate_effective_progs(struct cgroup *cgrp,
+ enum bpf_attach_type type,
+ struct bpf_prog_array __rcu *array)
+{
+ struct bpf_prog_array __rcu *old_array;
+
+ old_array = xchg(&cgrp->bpf.effective[type], array);
+ /* free prog array after grace period, since __cgroup_bpf_run_*()
+ * might be still walking the array
+ */
+ bpf_prog_array_free(old_array);
}
/**
* cgroup_bpf_inherit() - inherit effective programs from parent
* @cgrp: the cgroup to modify
- * @parent: the parent to inherit from
*/
-void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
+int cgroup_bpf_inherit(struct cgroup *cgrp)
{
- unsigned int type;
+/* has to use marco instead of const int, since compiler thinks
+ * that array below is variable length
+ */
+#define NR ARRAY_SIZE(cgrp->bpf.effective)
+ struct bpf_prog_array __rcu *arrays[NR] = {};
+ int i;
- for (type = 0; type < ARRAY_SIZE(cgrp->bpf.effective); type++) {
- struct bpf_prog *e;
+ for (i = 0; i < NR; i++)
+ INIT_LIST_HEAD(&cgrp->bpf.progs[i]);
- 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];
- }
+ for (i = 0; i < NR; i++)
+ if (compute_effective_progs(cgrp, i, &arrays[i]))
+ goto cleanup;
+
+ for (i = 0; i < NR; i++)
+ activate_effective_progs(cgrp, i, arrays[i]);
+
+ return 0;
+cleanup:
+ for (i = 0; i < NR; i++)
+ bpf_prog_array_free(arrays[i]);
+ return -ENOMEM;
}
+#define BPF_CGROUP_MAX_PROGS 64
+
/**
- * __cgroup_bpf_update() - Update the pinned program of a cgroup, and
+ * __cgroup_bpf_attach() - Attach the program to a cgroup, and
* propagate the change to descendants
* @cgrp: The cgroup which descendants to traverse
- * @parent: The parent of @cgrp, or %NULL if @cgrp is the root
- * @prog: A new program to pin
- * @type: Type of pinning operation (ingress/egress)
- *
- * Each cgroup has a set of two pointers for bpf programs; one for eBPF
- * programs it owns, and which is effective for execution.
- *
- * If @prog is not %NULL, this function attaches a new program to the cgroup
- * and releases the one that is currently attached, if any. @prog is then made
- * the effective program of type @type in that cgroup.
- *
- * If @prog is %NULL, the currently attached program of type @type is released,
- * and the effective program of the parent cgroup (if any) is inherited to
- * @cgrp.
- *
- * Then, the descendants of @cgrp are walked and the effective program for
- * each of them is set to the effective program of @cgrp unless the
- * descendant has its own program attached, in which case the subbranch is
- * skipped. This ensures that delegated subcgroups with own programs are left
- * untouched.
+ * @prog: A program to attach
+ * @type: Type of attach operation
*
* Must be called with cgroup_mutex held.
*/
-int __cgroup_bpf_update(struct cgroup *cgrp, struct cgroup *parent,
- struct bpf_prog *prog, enum bpf_attach_type type,
- bool new_overridable)
+int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
+ enum bpf_attach_type type, u32 flags)
{
- struct bpf_prog *old_prog, *effective = NULL;
- struct cgroup_subsys_state *pos;
- bool overridable = true;
-
- 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
- */
+ struct list_head *progs = &cgrp->bpf.progs[type];
+ struct bpf_prog *old_prog = NULL;
+ struct cgroup_subsys_state *css;
+ struct bpf_prog_list *pl;
+ bool pl_was_allocated;
+ u32 old_flags;
+ int err;
+
+ if ((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI))
+ /* invalid combination */
+ return -EINVAL;
+
+ if (!hierarchy_allows_attach(cgrp, type, flags))
return -EPERM;
- if (prog && effective && overridable != new_overridable)
- /* if parent has overridable prog attached, only
- * allow overridable programs in descendent cgroup
+ if (!list_empty(progs) && cgrp->bpf.flags[type] != flags)
+ /* Disallow attaching non-overridable on top
+ * of existing overridable in this cgroup.
+ * Disallow attaching multi-prog if overridable or none
*/
return -EPERM;
- 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_list_length(progs) >= BPF_CGROUP_MAX_PROGS)
+ return -E2BIG;
+
+ if (flags & BPF_F_ALLOW_MULTI) {
+ list_for_each_entry(pl, progs, node)
+ if (pl->prog == prog)
+ /* disallow attaching the same prog twice */
+ return -EINVAL;
+
+ pl = kmalloc(sizeof(*pl), GFP_KERNEL);
+ if (!pl)
+ return -ENOMEM;
+ pl_was_allocated = true;
+ pl->prog = prog;
+ list_add_tail(&pl->node, progs);
+ } else {
+ if (list_empty(progs)) {
+ pl = kmalloc(sizeof(*pl), GFP_KERNEL);
+ if (!pl)
+ return -ENOMEM;
+ pl_was_allocated = true;
+ list_add_tail(&pl->node, progs);
+ } else {
+ pl = list_first_entry(progs, typeof(*pl), node);
+ old_prog = pl->prog;
+ pl_was_allocated = false;
+ }
+ pl->prog = prog;
}
- if (!prog && !old_prog)
- /* report error when trying to detach and nothing is attached */
- return -ENOENT;
+ old_flags = cgrp->bpf.flags[type];
+ cgrp->bpf.flags[type] = flags;
- cgrp->bpf.prog[type] = prog;
+ /* allocate and recompute effective prog arrays */
+ css_for_each_descendant_pre(css, &cgrp->self) {
+ struct cgroup *desc = container_of(css, struct cgroup, self);
- 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) {
- pos = css_rightmost_descendant(pos);
- } else {
- rcu_assign_pointer(desc->bpf.effective[type],
- effective);
- desc->bpf.disallow_override[type] = !overridable;
- }
+ err = compute_effective_progs(desc, type, &desc->bpf.inactive);
+ if (err)
+ goto cleanup;
}
- if (prog)
- static_branch_inc(&cgroup_bpf_enabled_key);
+ /* all allocations were successful. Activate all prog arrays */
+ css_for_each_descendant_pre(css, &cgrp->self) {
+ struct cgroup *desc = container_of(css, struct cgroup, self);
+ activate_effective_progs(desc, type, desc->bpf.inactive);
+ desc->bpf.inactive = NULL;
+ }
+
+ static_branch_inc(&cgroup_bpf_enabled_key);
if (old_prog) {
bpf_prog_put(old_prog);
static_branch_dec(&cgroup_bpf_enabled_key);
}
return 0;
+
+cleanup:
+ /* oom while computing effective. Free all computed effective arrays
+ * since they were not activated
+ */
+ css_for_each_descendant_pre(css, &cgrp->self) {
+ struct cgroup *desc = container_of(css, struct cgroup, self);
+
+ bpf_prog_array_free(desc->bpf.inactive);
+ desc->bpf.inactive = NULL;
+ }
+
+ /* and cleanup the prog list */
+ pl->prog = old_prog;
+ if (pl_was_allocated) {
+ list_del(&pl->node);
+ kfree(pl);
+ }
+ return err;
+}
+
+/**
+ * __cgroup_bpf_detach() - Detach the program from a cgroup, and
+ * propagate the change to descendants
+ * @cgrp: The cgroup which descendants to traverse
+ * @prog: A program to detach or NULL
+ * @type: Type of detach operation
+ *
+ * Must be called with cgroup_mutex held.
+ */
+int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+ enum bpf_attach_type type, u32 unused_flags)
+{
+ struct list_head *progs = &cgrp->bpf.progs[type];
+ u32 flags = cgrp->bpf.flags[type];
+ struct bpf_prog *old_prog = NULL;
+ struct cgroup_subsys_state *css;
+ struct bpf_prog_list *pl;
+ int err;
+
+ if (flags & BPF_F_ALLOW_MULTI) {
+ if (!prog)
+ /* to detach MULTI prog the user has to specify valid FD
+ * of the program to be detached
+ */
+ return -EINVAL;
+ } else {
+ if (list_empty(progs))
+ /* report error when trying to detach and nothing is attached */
+ return -ENOENT;
+ }
+
+ if (flags & BPF_F_ALLOW_MULTI) {
+ /* find the prog and detach it */
+ list_for_each_entry(pl, progs, node) {
+ if (pl->prog != prog)
+ continue;
+ old_prog = prog;
+ /* mark it deleted, so it's ignored while
+ * recomputing effective
+ */
+ pl->prog = NULL;
+ break;
+ }
+ if (!old_prog)
+ return -ENOENT;
+ } else {
+ /* to maintain backward compatibility NONE and OVERRIDE cgroups
+ * allow detaching with invalid FD (prog==NULL)
+ */
+ pl = list_first_entry(progs, typeof(*pl), node);
+ old_prog = pl->prog;
+ pl->prog = NULL;
+ }
+
+ /* allocate and recompute effective prog arrays */
+ css_for_each_descendant_pre(css, &cgrp->self) {
+ struct cgroup *desc = container_of(css, struct cgroup, self);
+
+ err = compute_effective_progs(desc, type, &desc->bpf.inactive);
+ if (err)
+ goto cleanup;
+ }
+
+ /* all allocations were successful. Activate all prog arrays */
+ css_for_each_descendant_pre(css, &cgrp->self) {
+ struct cgroup *desc = container_of(css, struct cgroup, self);
+
+ activate_effective_progs(desc, type, desc->bpf.inactive);
+ desc->bpf.inactive = NULL;
+ }
+
+ /* now can actually delete it from this cgroup list */
+ list_del(&pl->node);
+ kfree(pl);
+ if (list_empty(progs))
+ /* last program was detached, reset flags to zero */
+ cgrp->bpf.flags[type] = 0;
+
+ bpf_prog_put(old_prog);
+ static_branch_dec(&cgroup_bpf_enabled_key);
+ return 0;
+
+cleanup:
+ /* oom while computing effective. Free all computed effective arrays
+ * since they were not activated
+ */
+ css_for_each_descendant_pre(css, &cgrp->self) {
+ struct cgroup *desc = container_of(css, struct cgroup, self);
+
+ bpf_prog_array_free(desc->bpf.inactive);
+ desc->bpf.inactive = NULL;
+ }
+
+ /* and restore back old_prog */
+ pl->prog = old_prog;
+ return err;
}
/**
struct sk_buff *skb,
enum bpf_attach_type type)
{
- struct bpf_prog *prog;
+ unsigned int offset = skb->data - skb_network_header(skb);
+ struct sock *save_sk;
struct cgroup *cgrp;
- int ret = 0;
+ int ret;
if (!sk || !sk_fullsock(sk))
return 0;
- if (sk->sk_family != AF_INET &&
- sk->sk_family != AF_INET6)
+ if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
return 0;
cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
-
- rcu_read_lock();
-
- prog = rcu_dereference(cgrp->bpf.effective[type]);
- if (prog) {
- unsigned int offset = skb->data - skb_network_header(skb);
- struct sock *save_sk = skb->sk;
-
- skb->sk = sk;
- __skb_push(skb, offset);
- ret = bpf_prog_run_save_cb(prog, skb) == 1 ? 0 : -EPERM;
- __skb_pull(skb, offset);
- skb->sk = save_sk;
- }
-
- rcu_read_unlock();
-
- return ret;
+ save_sk = skb->sk;
+ skb->sk = sk;
+ __skb_push(skb, offset);
+ ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], skb,
+ bpf_prog_run_save_cb);
+ __skb_pull(skb, offset);
+ skb->sk = save_sk;
+ return ret == 1 ? 0 : -EPERM;
}
EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb);
enum bpf_attach_type type)
{
struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- struct bpf_prog *prog;
- int ret = 0;
-
-
- rcu_read_lock();
-
- prog = rcu_dereference(cgrp->bpf.effective[type]);
- if (prog)
- ret = BPF_PROG_RUN(prog, sk) == 1 ? 0 : -EPERM;
+ int ret;
- rcu_read_unlock();
-
- return ret;
+ ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], sk, BPF_PROG_RUN);
+ return ret == 1 ? 0 : -EPERM;
}
EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
enum bpf_attach_type type)
{
struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- struct bpf_prog *prog;
- int ret = 0;
-
-
- rcu_read_lock();
-
- prog = rcu_dereference(cgrp->bpf.effective[type]);
- if (prog)
- ret = BPF_PROG_RUN(prog, sock_ops) == 1 ? 0 : -EPERM;
-
- rcu_read_unlock();
+ int ret;
- return ret;
+ ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], sock_ops,
+ BPF_PROG_RUN);
+ return ret == 1 ? 0 : -EPERM;
}
EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops);
projects / openwrt / staging / blogic.git / commitdiff