Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2014 insertions, 0 deletions

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
new file mode 100644
index 000000000..85927c2aa
--- /dev/null
+++ b/kernel/bpf/cgroup.c
@@ -0,0 +1,2014 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Functions to manage eBPF programs attached to cgroups
+ *
+ * Copyright (c) 2016 Daniel Mack
+ */
+
+#include <linux/kernel.h>
+#include <linux/atomic.h>
+#include <linux/cgroup.h>
+#include <linux/filter.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/string.h>
+#include <linux/bpf.h>
+#include <linux/bpf-cgroup.h>
+#include <net/sock.h>
+#include <net/bpf_sk_storage.h>
+
+#include "../cgroup/cgroup-internal.h"
+
+DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);
+EXPORT_SYMBOL(cgroup_bpf_enabled_key);
+
+void cgroup_bpf_offline(struct cgroup *cgrp)
+{
+	cgroup_get(cgrp);
+	percpu_ref_kill(&cgrp->bpf.refcnt);
+}
+
+static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[])
+{
+	enum bpf_cgroup_storage_type stype;
+
+	for_each_cgroup_storage_type(stype)
+		bpf_cgroup_storage_free(storages[stype]);
+}
+
+static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[],
+				     struct bpf_cgroup_storage *new_storages[],
+				     enum bpf_attach_type type,
+				     struct bpf_prog *prog,
+				     struct cgroup *cgrp)
+{
+	enum bpf_cgroup_storage_type stype;
+	struct bpf_cgroup_storage_key key;
+	struct bpf_map *map;
+
+	key.cgroup_inode_id = cgroup_id(cgrp);
+	key.attach_type = type;
+
+	for_each_cgroup_storage_type(stype) {
+		map = prog->aux->cgroup_storage[stype];
+		if (!map)
+			continue;
+
+		storages[stype] = cgroup_storage_lookup((void *)map, &key, false);
+		if (storages[stype])
+			continue;
+
+		storages[stype] = bpf_cgroup_storage_alloc(prog, stype);
+		if (IS_ERR(storages[stype])) {
+			bpf_cgroup_storages_free(new_storages);
+			return -ENOMEM;
+		}
+
+		new_storages[stype] = storages[stype];
+	}
+
+	return 0;
+}
+
+static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[],
+				       struct bpf_cgroup_storage *src[])
+{
+	enum bpf_cgroup_storage_type stype;
+
+	for_each_cgroup_storage_type(stype)
+		dst[stype] = src[stype];
+}
+
+static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[],
+				     struct cgroup *cgrp,
+				     enum bpf_attach_type attach_type)
+{
+	enum bpf_cgroup_storage_type stype;
+
+	for_each_cgroup_storage_type(stype)
+		bpf_cgroup_storage_link(storages[stype], cgrp, attach_type);
+}
+
+/* Called when bpf_cgroup_link is auto-detached from dying cgroup.
+ * It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It
+ * doesn't free link memory, which will eventually be done by bpf_link's
+ * release() callback, when its last FD is closed.
+ */
+static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link)
+{
+	cgroup_put(link->cgroup);
+	link->cgroup = NULL;
+}
+
+/**
+ * cgroup_bpf_release() - put references of all bpf programs and
+ *                        release all cgroup bpf data
+ * @work: work structure embedded into the cgroup to modify
+ */
+static void cgroup_bpf_release(struct work_struct *work)
+{
+	struct cgroup *p, *cgrp = container_of(work, struct cgroup,
+					       bpf.release_work);
+	struct bpf_prog_array *old_array;
+	struct list_head *storages = &cgrp->bpf.storages;
+	struct bpf_cgroup_storage *storage, *stmp;
+
+	unsigned int type;
+
+	mutex_lock(&cgroup_mutex);
+
+	for (type = 0; type < ARRAY_SIZE(cgrp->bpf.progs); type++) {
+		struct list_head *progs = &cgrp->bpf.progs[type];
+		struct bpf_prog_list *pl, *pltmp;
+
+		list_for_each_entry_safe(pl, pltmp, progs, node) {
+			list_del(&pl->node);
+			if (pl->prog)
+				bpf_prog_put(pl->prog);
+			if (pl->link)
+				bpf_cgroup_link_auto_detach(pl->link);
+			kfree(pl);
+			static_branch_dec(&cgroup_bpf_enabled_key);
+		}
+		old_array = rcu_dereference_protected(
+				cgrp->bpf.effective[type],
+				lockdep_is_held(&cgroup_mutex));
+		bpf_prog_array_free(old_array);
+	}
+
+	list_for_each_entry_safe(storage, stmp, storages, list_cg) {
+		bpf_cgroup_storage_unlink(storage);
+		bpf_cgroup_storage_free(storage);
+	}
+
+	mutex_unlock(&cgroup_mutex);
+
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_put(p);
+
+	percpu_ref_exit(&cgrp->bpf.refcnt);
+	cgroup_put(cgrp);
+}
+
+/**
+ * cgroup_bpf_release_fn() - callback used to schedule releasing
+ *                           of bpf cgroup data
+ * @ref: percpu ref counter structure
+ */
+static void cgroup_bpf_release_fn(struct percpu_ref *ref)
+{
+	struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt);
+
+	INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release);
+	queue_work(system_wq, &cgrp->bpf.release_work);
+}
+
+/* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through
+ * link or direct prog.
+ */
+static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl)
+{
+	if (pl->prog)
+		return pl->prog;
+	if (pl->link)
+		return pl->link->link.prog;
+	return NULL;
+}
+
+/* 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 (!prog_list_prog(pl))
+			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)
+{
+	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 **array)
+{
+	struct bpf_prog_array_item *item;
+	struct bpf_prog_array *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))
+			continue;
+
+		list_for_each_entry(pl, &p->bpf.progs[type], node) {
+			if (!prog_list_prog(pl))
+				continue;
+
+			item = &progs->items[cnt];
+			item->prog = prog_list_prog(pl);
+			bpf_cgroup_storages_assign(item->cgroup_storage,
+						   pl->storage);
+			cnt++;
+		}
+	} while ((p = cgroup_parent(p)));
+
+	*array = progs;
+	return 0;
+}
+
+static void activate_effective_progs(struct cgroup *cgrp,
+				     enum bpf_attach_type type,
+				     struct bpf_prog_array *old_array)
+{
+	old_array = rcu_replace_pointer(cgrp->bpf.effective[type], old_array,
+					lockdep_is_held(&cgroup_mutex));
+	/* 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
+ */
+int cgroup_bpf_inherit(struct cgroup *cgrp)
+{
+/* 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 *arrays[NR] = {};
+	struct cgroup *p;
+	int ret, i;
+
+	ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0,
+			      GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_get(p);
+
+	for (i = 0; i < NR; i++)
+		INIT_LIST_HEAD(&cgrp->bpf.progs[i]);
+
+	INIT_LIST_HEAD(&cgrp->bpf.storages);
+
+	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]);
+
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_put(p);
+
+	percpu_ref_exit(&cgrp->bpf.refcnt);
+
+	return -ENOMEM;
+}
+
+static int update_effective_progs(struct cgroup *cgrp,
+				  enum bpf_attach_type type)
+{
+	struct cgroup_subsys_state *css;
+	int err;
+
+	/* allocate and recompute effective prog arrays */
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt))
+			continue;
+
+		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);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt)) {
+			if (unlikely(desc->bpf.inactive)) {
+				bpf_prog_array_free(desc->bpf.inactive);
+				desc->bpf.inactive = NULL;
+			}
+			continue;
+		}
+
+		activate_effective_progs(desc, type, desc->bpf.inactive);
+		desc->bpf.inactive = NULL;
+	}
+
+	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;
+	}
+
+	return err;
+}
+
+#define BPF_CGROUP_MAX_PROGS 64
+
+static struct bpf_prog_list *find_attach_entry(struct list_head *progs,
+					       struct bpf_prog *prog,
+					       struct bpf_cgroup_link *link,
+					       struct bpf_prog *replace_prog,
+					       bool allow_multi)
+{
+	struct bpf_prog_list *pl;
+
+	/* single-attach case */
+	if (!allow_multi) {
+		if (list_empty(progs))
+			return NULL;
+		return list_first_entry(progs, typeof(*pl), node);
+	}
+
+	list_for_each_entry(pl, progs, node) {
+		if (prog && pl->prog == prog && prog != replace_prog)
+			/* disallow attaching the same prog twice */
+			return ERR_PTR(-EINVAL);
+		if (link && pl->link == link)
+			/* disallow attaching the same link twice */
+			return ERR_PTR(-EINVAL);
+	}
+
+	/* direct prog multi-attach w/ replacement case */
+	if (replace_prog) {
+		list_for_each_entry(pl, progs, node) {
+			if (pl->prog == replace_prog)
+				/* a match found */
+				return pl;
+		}
+		/* prog to replace not found for cgroup */
+		return ERR_PTR(-ENOENT);
+	}
+
+	return NULL;
+}
+
+/**
+ * __cgroup_bpf_attach() - Attach the program or the link to a cgroup, and
+ *                         propagate the change to descendants
+ * @cgrp: The cgroup which descendants to traverse
+ * @prog: A program to attach
+ * @link: A link to attach
+ * @replace_prog: Previously attached program to replace if BPF_F_REPLACE is set
+ * @type: Type of attach operation
+ * @flags: Option flags
+ *
+ * Exactly one of @prog or @link can be non-null.
+ * Must be called with cgroup_mutex held.
+ */
+int __cgroup_bpf_attach(struct cgroup *cgrp,
+			struct bpf_prog *prog, struct bpf_prog *replace_prog,
+			struct bpf_cgroup_link *link,
+			enum bpf_attach_type type, u32 flags)
+{
+	u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI));
+	struct list_head *progs = &cgrp->bpf.progs[type];
+	struct bpf_prog *old_prog = NULL;
+	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
+	struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
+	struct bpf_prog_list *pl;
+	int err;
+
+	if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) ||
+	    ((flags & BPF_F_REPLACE) && !(flags & BPF_F_ALLOW_MULTI)))
+		/* invalid combination */
+		return -EINVAL;
+	if (link && (prog || replace_prog))
+		/* only either link or prog/replace_prog can be specified */
+		return -EINVAL;
+	if (!!replace_prog != !!(flags & BPF_F_REPLACE))
+		/* replace_prog implies BPF_F_REPLACE, and vice versa */
+		return -EINVAL;
+
+	if (!hierarchy_allows_attach(cgrp, type))
+		return -EPERM;
+
+	if (!list_empty(progs) && cgrp->bpf.flags[type] != saved_flags)
+		/* Disallow attaching non-overridable on top
+		 * of existing overridable in this cgroup.
+		 * Disallow attaching multi-prog if overridable or none
+		 */
+		return -EPERM;
+
+	if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS)
+		return -E2BIG;
+
+	pl = find_attach_entry(progs, prog, link, replace_prog,
+			       flags & BPF_F_ALLOW_MULTI);
+	if (IS_ERR(pl))
+		return PTR_ERR(pl);
+
+	if (bpf_cgroup_storages_alloc(storage, new_storage, type,
+				      prog ? : link->link.prog, cgrp))
+		return -ENOMEM;
+
+	if (pl) {
+		old_prog = pl->prog;
+	} else {
+		pl = kmalloc(sizeof(*pl), GFP_KERNEL);
+		if (!pl) {
+			bpf_cgroup_storages_free(new_storage);
+			return -ENOMEM;
+		}
+		list_add_tail(&pl->node, progs);
+	}
+
+	pl->prog = prog;
+	pl->link = link;
+	bpf_cgroup_storages_assign(pl->storage, storage);
+	cgrp->bpf.flags[type] = saved_flags;
+
+	err = update_effective_progs(cgrp, type);
+	if (err)
+		goto cleanup;
+
+	if (old_prog)
+		bpf_prog_put(old_prog);
+	else
+		static_branch_inc(&cgroup_bpf_enabled_key);
+	bpf_cgroup_storages_link(new_storage, cgrp, type);
+	return 0;
+
+cleanup:
+	if (old_prog) {
+		pl->prog = old_prog;
+		pl->link = NULL;
+	}
+	bpf_cgroup_storages_free(new_storage);
+	if (!old_prog) {
+		list_del(&pl->node);
+		kfree(pl);
+	}
+	return err;
+}
+
+/* Swap updated BPF program for given link in effective program arrays across
+ * all descendant cgroups. This function is guaranteed to succeed.
+ */
+static void replace_effective_prog(struct cgroup *cgrp,
+				   enum bpf_attach_type type,
+				   struct bpf_cgroup_link *link)
+{
+	struct bpf_prog_array_item *item;
+	struct cgroup_subsys_state *css;
+	struct bpf_prog_array *progs;
+	struct bpf_prog_list *pl;
+	struct list_head *head;
+	struct cgroup *cg;
+	int pos;
+
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt))
+			continue;
+
+		/* find position of link in effective progs array */
+		for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) {
+			if (pos && !(cg->bpf.flags[type] & BPF_F_ALLOW_MULTI))
+				continue;
+
+			head = &cg->bpf.progs[type];
+			list_for_each_entry(pl, head, node) {
+				if (!prog_list_prog(pl))
+					continue;
+				if (pl->link == link)
+					goto found;
+				pos++;
+			}
+		}
+found:
+		BUG_ON(!cg);
+		progs = rcu_dereference_protected(
+				desc->bpf.effective[type],
+				lockdep_is_held(&cgroup_mutex));
+		item = &progs->items[pos];
+		WRITE_ONCE(item->prog, link->link.prog);
+	}
+}
+
+/**
+ * __cgroup_bpf_replace() - Replace link's program and propagate the change
+ *                          to descendants
+ * @cgrp: The cgroup which descendants to traverse
+ * @link: A link for which to replace BPF program
+ * @type: Type of attach operation
+ *
+ * Must be called with cgroup_mutex held.
+ */
+static int __cgroup_bpf_replace(struct cgroup *cgrp,
+				struct bpf_cgroup_link *link,
+				struct bpf_prog *new_prog)
+{
+	struct list_head *progs = &cgrp->bpf.progs[link->type];
+	struct bpf_prog *old_prog;
+	struct bpf_prog_list *pl;
+	bool found = false;
+
+	if (link->link.prog->type != new_prog->type)
+		return -EINVAL;
+
+	list_for_each_entry(pl, progs, node) {
+		if (pl->link == link) {
+			found = true;
+			break;
+		}
+	}
+	if (!found)
+		return -ENOENT;
+
+	old_prog = xchg(&link->link.prog, new_prog);
+	replace_effective_prog(cgrp, link->type, link);
+	bpf_prog_put(old_prog);
+	return 0;
+}
+
+static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog,
+			      struct bpf_prog *old_prog)
+{
+	struct bpf_cgroup_link *cg_link;
+	int ret;
+
+	cg_link = container_of(link, struct bpf_cgroup_link, link);
+
+	mutex_lock(&cgroup_mutex);
+	/* link might have been auto-released by dying cgroup, so fail */
+	if (!cg_link->cgroup) {
+		ret = -ENOLINK;
+		goto out_unlock;
+	}
+	if (old_prog && link->prog != old_prog) {
+		ret = -EPERM;
+		goto out_unlock;
+	}
+	ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog);
+out_unlock:
+	mutex_unlock(&cgroup_mutex);
+	return ret;
+}
+
+static struct bpf_prog_list *find_detach_entry(struct list_head *progs,
+					       struct bpf_prog *prog,
+					       struct bpf_cgroup_link *link,
+					       bool allow_multi)
+{
+	struct bpf_prog_list *pl;
+
+	if (!allow_multi) {
+		if (list_empty(progs))
+			/* report error when trying to detach and nothing is attached */
+			return ERR_PTR(-ENOENT);
+
+		/* to maintain backward compatibility NONE and OVERRIDE cgroups
+		 * allow detaching with invalid FD (prog==NULL) in legacy mode
+		 */
+		return list_first_entry(progs, typeof(*pl), node);
+	}
+
+	if (!prog && !link)
+		/* to detach MULTI prog the user has to specify valid FD
+		 * of the program or link to be detached
+		 */
+		return ERR_PTR(-EINVAL);
+
+	/* find the prog or link and detach it */
+	list_for_each_entry(pl, progs, node) {
+		if (pl->prog == prog && pl->link == link)
+			return pl;
+	}
+	return ERR_PTR(-ENOENT);
+}
+
+/**
+ * purge_effective_progs() - After compute_effective_progs fails to alloc new
+ *			     cgrp->bpf.inactive table we can recover by
+ *			     recomputing the array in place.
+ *
+ * @cgrp: The cgroup which descendants to travers
+ * @prog: A program to detach or NULL
+ * @link: A link to detach or NULL
+ * @type: Type of detach operation
+ */
+static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog,
+				  struct bpf_cgroup_link *link,
+				  enum bpf_attach_type type)
+{
+	struct cgroup_subsys_state *css;
+	struct bpf_prog_array *progs;
+	struct bpf_prog_list *pl;
+	struct list_head *head;
+	struct cgroup *cg;
+	int pos;
+
+	/* recompute effective prog array in place */
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt))
+			continue;
+
+		/* find position of link or prog in effective progs array */
+		for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) {
+			if (pos && !(cg->bpf.flags[type] & BPF_F_ALLOW_MULTI))
+				continue;
+
+			head = &cg->bpf.progs[type];
+			list_for_each_entry(pl, head, node) {
+				if (!prog_list_prog(pl))
+					continue;
+				if (pl->prog == prog && pl->link == link)
+					goto found;
+				pos++;
+			}
+		}
+
+		/* no link or prog match, skip the cgroup of this layer */
+		continue;
+found:
+		progs = rcu_dereference_protected(
+				desc->bpf.effective[type],
+				lockdep_is_held(&cgroup_mutex));
+
+		/* Remove the program from the array */
+		WARN_ONCE(bpf_prog_array_delete_safe_at(progs, pos),
+			  "Failed to purge a prog from array at index %d", pos);
+	}
+}
+
+/**
+ * __cgroup_bpf_detach() - Detach the program or link from a cgroup, and
+ *                         propagate the change to descendants
+ * @cgrp: The cgroup which descendants to traverse
+ * @prog: A program to detach or NULL
+ * @prog: A link to detach or NULL
+ * @type: Type of detach operation
+ *
+ * At most one of @prog or @link can be non-NULL.
+ * Must be called with cgroup_mutex held.
+ */
+int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+			struct bpf_cgroup_link *link, enum bpf_attach_type type)
+{
+	struct list_head *progs = &cgrp->bpf.progs[type];
+	u32 flags = cgrp->bpf.flags[type];
+	struct bpf_prog_list *pl;
+	struct bpf_prog *old_prog;
+
+	if (prog && link)
+		/* only one of prog or link can be specified */
+		return -EINVAL;
+
+	pl = find_detach_entry(progs, prog, link, flags & BPF_F_ALLOW_MULTI);
+	if (IS_ERR(pl))
+		return PTR_ERR(pl);
+
+	/* mark it deleted, so it's ignored while recomputing effective */
+	old_prog = pl->prog;
+	pl->prog = NULL;
+	pl->link = NULL;
+
+	if (update_effective_progs(cgrp, type)) {
+		/* if update effective array failed replace the prog with a dummy prog*/
+		pl->prog = old_prog;
+		pl->link = link;
+		purge_effective_progs(cgrp, old_prog, link, type);
+	}
+
+	/* 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;
+	if (old_prog)
+		bpf_prog_put(old_prog);
+	static_branch_dec(&cgroup_bpf_enabled_key);
+	return 0;
+}
+
+/* Must be called with cgroup_mutex held to avoid races. */
+int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+		       union bpf_attr __user *uattr)
+{
+	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+	enum bpf_attach_type type = attr->query.attach_type;
+	struct list_head *progs = &cgrp->bpf.progs[type];
+	u32 flags = cgrp->bpf.flags[type];
+	struct bpf_prog_array *effective;
+	struct bpf_prog *prog;
+	int cnt, ret = 0, i;
+
+	effective = rcu_dereference_protected(cgrp->bpf.effective[type],
+					      lockdep_is_held(&cgroup_mutex));
+
+	if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE)
+		cnt = bpf_prog_array_length(effective);
+	else
+		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)))
+		return -EFAULT;
+	if (attr->query.prog_cnt == 0 || !prog_ids || !cnt)
+		/* return early if user requested only program count + flags */
+		return 0;
+	if (attr->query.prog_cnt < cnt) {
+		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;
+
+		i = 0;
+		list_for_each_entry(pl, progs, node) {
+			prog = prog_list_prog(pl);
+			id = prog->aux->id;
+			if (copy_to_user(prog_ids + i, &id, sizeof(id)))
+				return -EFAULT;
+			if (++i == cnt)
+				break;
+		}
+	}
+	return ret;
+}
+
+int cgroup_bpf_prog_attach(const union bpf_attr *attr,
+			   enum bpf_prog_type ptype, struct bpf_prog *prog)
+{
+	struct bpf_prog *replace_prog = NULL;
+	struct cgroup *cgrp;
+	int ret;
+
+	cgrp = cgroup_get_from_fd(attr->target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	if ((attr->attach_flags & BPF_F_ALLOW_MULTI) &&
+	    (attr->attach_flags & BPF_F_REPLACE)) {
+		replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, ptype);
+		if (IS_ERR(replace_prog)) {
+			cgroup_put(cgrp);
+			return PTR_ERR(replace_prog);
+		}
+	}
+
+	ret = cgroup_bpf_attach(cgrp, prog, replace_prog, NULL,
+				attr->attach_type, attr->attach_flags);
+
+	if (replace_prog)
+		bpf_prog_put(replace_prog);
+	cgroup_put(cgrp);
+	return ret;
+}
+
+int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
+{
+	struct bpf_prog *prog;
+	struct cgroup *cgrp;
+	int ret;
+
+	cgrp = cgroup_get_from_fd(attr->target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
+	if (IS_ERR(prog))
+		prog = NULL;
+
+	ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type);
+	if (prog)
+		bpf_prog_put(prog);
+
+	cgroup_put(cgrp);
+	return ret;
+}
+
+static void bpf_cgroup_link_release(struct bpf_link *link)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+	struct cgroup *cg;
+
+	/* link might have been auto-detached by dying cgroup already,
+	 * in that case our work is done here
+	 */
+	if (!cg_link->cgroup)
+		return;
+
+	mutex_lock(&cgroup_mutex);
+
+	/* re-check cgroup under lock again */
+	if (!cg_link->cgroup) {
+		mutex_unlock(&cgroup_mutex);
+		return;
+	}
+
+	WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link,
+				    cg_link->type));
+
+	cg = cg_link->cgroup;
+	cg_link->cgroup = NULL;
+
+	mutex_unlock(&cgroup_mutex);
+
+	cgroup_put(cg);
+}
+
+static void bpf_cgroup_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+
+	kfree(cg_link);
+}
+
+static int bpf_cgroup_link_detach(struct bpf_link *link)
+{
+	bpf_cgroup_link_release(link);
+
+	return 0;
+}
+
+static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link,
+					struct seq_file *seq)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+	u64 cg_id = 0;
+
+	mutex_lock(&cgroup_mutex);
+	if (cg_link->cgroup)
+		cg_id = cgroup_id(cg_link->cgroup);
+	mutex_unlock(&cgroup_mutex);
+
+	seq_printf(seq,
+		   "cgroup_id:\t%llu\n"
+		   "attach_type:\t%d\n",
+		   cg_id,
+		   cg_link->type);
+}
+
+static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link,
+					  struct bpf_link_info *info)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+	u64 cg_id = 0;
+
+	mutex_lock(&cgroup_mutex);
+	if (cg_link->cgroup)
+		cg_id = cgroup_id(cg_link->cgroup);
+	mutex_unlock(&cgroup_mutex);
+
+	info->cgroup.cgroup_id = cg_id;
+	info->cgroup.attach_type = cg_link->type;
+	return 0;
+}
+
+static const struct bpf_link_ops bpf_cgroup_link_lops = {
+	.release = bpf_cgroup_link_release,
+	.dealloc = bpf_cgroup_link_dealloc,
+	.detach = bpf_cgroup_link_detach,
+	.update_prog = cgroup_bpf_replace,
+	.show_fdinfo = bpf_cgroup_link_show_fdinfo,
+	.fill_link_info = bpf_cgroup_link_fill_link_info,
+};
+
+int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	struct bpf_link_primer link_primer;
+	struct bpf_cgroup_link *link;
+	struct cgroup *cgrp;
+	int err;
+
+	if (attr->link_create.flags)
+		return -EINVAL;
+
+	cgrp = cgroup_get_from_fd(attr->link_create.target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	link = kzalloc(sizeof(*link), GFP_USER);
+	if (!link) {
+		err = -ENOMEM;
+		goto out_put_cgroup;
+	}
+	bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops,
+		      prog);
+	link->cgroup = cgrp;
+	link->type = attr->link_create.attach_type;
+
+	err  = bpf_link_prime(&link->link, &link_primer);
+	if (err) {
+		kfree(link);
+		goto out_put_cgroup;
+	}
+
+	err = cgroup_bpf_attach(cgrp, NULL, NULL, link, link->type,
+				BPF_F_ALLOW_MULTI);
+	if (err) {
+		bpf_link_cleanup(&link_primer);
+		goto out_put_cgroup;
+	}
+
+	return bpf_link_settle(&link_primer);
+
+out_put_cgroup:
+	cgroup_put(cgrp);
+	return err;
+}
+
+int cgroup_bpf_prog_query(const union bpf_attr *attr,
+			  union bpf_attr __user *uattr)
+{
+	struct cgroup *cgrp;
+	int ret;
+
+	cgrp = cgroup_get_from_fd(attr->query.target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	ret = cgroup_bpf_query(cgrp, attr, uattr);
+
+	cgroup_put(cgrp);
+	return ret;
+}
+
+/**
+ * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering
+ * @sk: The socket sending or receiving traffic
+ * @skb: The skb that is being sent or received
+ * @type: The type of program to be exectuted
+ *
+ * If no socket is passed, or the socket is not of type INET or INET6,
+ * this function does nothing and returns 0.
+ *
+ * The program type passed in via @type must be suitable for network
+ * filtering. No further check is performed to assert that.
+ *
+ * For egress packets, this function can return:
+ *   NET_XMIT_SUCCESS    (0)	- continue with packet output
+ *   NET_XMIT_DROP       (1)	- drop packet and notify TCP to call cwr
+ *   NET_XMIT_CN         (2)	- continue with packet output and notify TCP
+ *				  to call cwr
+ *   -EPERM			- drop packet
+ *
+ * For ingress packets, this function will return -EPERM if any
+ * attached program was found and if it returned != 1 during execution.
+ * Otherwise 0 is returned.
+ */
+int __cgroup_bpf_run_filter_skb(struct sock *sk,
+				struct sk_buff *skb,
+				enum bpf_attach_type type)
+{
+	unsigned int offset = skb->data - skb_network_header(skb);
+	struct sock *save_sk;
+	void *saved_data_end;
+	struct cgroup *cgrp;
+	int ret;
+
+	if (!sk || !sk_fullsock(sk))
+		return 0;
+
+	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
+		return 0;
+
+	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	save_sk = skb->sk;
+	skb->sk = sk;
+	__skb_push(skb, offset);
+
+	/* compute pointers for the bpf prog */
+	bpf_compute_and_save_data_end(skb, &saved_data_end);
+
+	if (type == BPF_CGROUP_INET_EGRESS) {
+		ret = BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY(
+			cgrp->bpf.effective[type], skb, __bpf_prog_run_save_cb);
+	} else {
+		ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], skb,
+					  __bpf_prog_run_save_cb);
+		ret = (ret == 1 ? 0 : -EPERM);
+	}
+	bpf_restore_data_end(skb, saved_data_end);
+	__skb_pull(skb, offset);
+	skb->sk = save_sk;
+
+	return ret;
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb);
+
+/**
+ * __cgroup_bpf_run_filter_sk() - Run a program on a sock
+ * @sk: sock structure to manipulate
+ * @type: The type of program to be exectuted
+ *
+ * socket is passed is expected to be of type INET or INET6.
+ *
+ * The program type passed in via @type must be suitable for sock
+ * filtering. No further check is performed to assert that.
+ *
+ * This function will return %-EPERM if any if an attached program was found
+ * and if it returned != 1 during execution. In all other cases, 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sk(struct sock *sk,
+			       enum bpf_attach_type type)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	int 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);
+
+/**
+ * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and
+ *                                       provided by user sockaddr
+ * @sk: sock struct that will use sockaddr
+ * @uaddr: sockaddr struct provided by user
+ * @type: The type of program to be exectuted
+ * @t_ctx: Pointer to attach type specific context
+ *
+ * socket is expected to be of type INET or INET6.
+ *
+ * This function will return %-EPERM if an attached program is found and
+ * returned value != 1 during execution. In all other cases, 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
+				      struct sockaddr *uaddr,
+				      enum bpf_attach_type type,
+				      void *t_ctx)
+{
+	struct bpf_sock_addr_kern ctx = {
+		.sk = sk,
+		.uaddr = uaddr,
+		.t_ctx = t_ctx,
+	};
+	struct sockaddr_storage unspec;
+	struct cgroup *cgrp;
+	int ret;
+
+	/* Check socket family since not all sockets represent network
+	 * endpoint (e.g. AF_UNIX).
+	 */
+	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
+		return 0;
+
+	if (!ctx.uaddr) {
+		memset(&unspec, 0, sizeof(unspec));
+		ctx.uaddr = (struct sockaddr *)&unspec;
+	}
+
+	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN);
+
+	return ret == 1 ? 0 : -EPERM;
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr);
+
+/**
+ * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock
+ * @sk: socket to get cgroup from
+ * @sock_ops: bpf_sock_ops_kern struct to pass to program. Contains
+ * sk with connection information (IP addresses, etc.) May not contain
+ * cgroup info if it is a req sock.
+ * @type: The type of program to be exectuted
+ *
+ * socket passed is expected to be of type INET or INET6.
+ *
+ * The program type passed in via @type must be suitable for sock_ops
+ * filtering. No further check is performed to assert that.
+ *
+ * This function will return %-EPERM if any if an attached program was found
+ * and if it returned != 1 during execution. In all other cases, 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
+				     struct bpf_sock_ops_kern *sock_ops,
+				     enum bpf_attach_type type)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	int 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);
+
+int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
+				      short access, enum bpf_attach_type type)
+{
+	struct cgroup *cgrp;
+	struct bpf_cgroup_dev_ctx ctx = {
+		.access_type = (access << 16) | dev_type,
+		.major = major,
+		.minor = minor,
+	};
+	int allow = 1;
+
+	rcu_read_lock();
+	cgrp = task_dfl_cgroup(current);
+	allow = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx,
+				   BPF_PROG_RUN);
+	rcu_read_unlock();
+
+	return !allow;
+}
+
+static const struct bpf_func_proto *
+cgroup_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_get_current_uid_gid:
+		return &bpf_get_current_uid_gid_proto;
+	case BPF_FUNC_get_local_storage:
+		return &bpf_get_local_storage_proto;
+	case BPF_FUNC_get_current_cgroup_id:
+		return &bpf_get_current_cgroup_id_proto;
+	case BPF_FUNC_perf_event_output:
+		return &bpf_event_output_data_proto;
+	default:
+		return bpf_base_func_proto(func_id);
+	}
+}
+
+static const struct bpf_func_proto *
+cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	return cgroup_base_func_proto(func_id, prog);
+}
+
+static bool cgroup_dev_is_valid_access(int off, int size,
+				       enum bpf_access_type type,
+				       const struct bpf_prog *prog,
+				       struct bpf_insn_access_aux *info)
+{
+	const int size_default = sizeof(__u32);
+
+	if (type == BPF_WRITE)
+		return false;
+
+	if (off < 0 || off + size > sizeof(struct bpf_cgroup_dev_ctx))
+		return false;
+	/* The verifier guarantees that size > 0. */
+	if (off % size != 0)
+		return false;
+
+	switch (off) {
+	case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type):
+		bpf_ctx_record_field_size(info, size_default);
+		if (!bpf_ctx_narrow_access_ok(off, size, size_default))
+			return false;
+		break;
+	default:
+		if (size != size_default)
+			return false;
+	}
+
+	return true;
+}
+
+const struct bpf_prog_ops cg_dev_prog_ops = {
+};
+
+const struct bpf_verifier_ops cg_dev_verifier_ops = {
+	.get_func_proto		= cgroup_dev_func_proto,
+	.is_valid_access	= cgroup_dev_is_valid_access,
+};
+
+/**
+ * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl
+ *
+ * @head: sysctl table header
+ * @table: sysctl table
+ * @write: sysctl is being read (= 0) or written (= 1)
+ * @buf: pointer to buffer (in and out)
+ * @pcount: value-result argument: value is size of buffer pointed to by @buf,
+ *	result is size of @new_buf if program set new value, initial value
+ *	otherwise
+ * @ppos: value-result argument: value is position at which read from or write
+ *	to sysctl is happening, result is new position if program overrode it,
+ *	initial value otherwise
+ * @type: type of program to be executed
+ *
+ * Program is run when sysctl is being accessed, either read or written, and
+ * can allow or deny such access.
+ *
+ * This function will return %-EPERM if an attached program is found and
+ * returned value != 1 during execution. In all other cases 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
+				   struct ctl_table *table, int write,
+				   char **buf, size_t *pcount, loff_t *ppos,
+				   enum bpf_attach_type type)
+{
+	struct bpf_sysctl_kern ctx = {
+		.head = head,
+		.table = table,
+		.write = write,
+		.ppos = ppos,
+		.cur_val = NULL,
+		.cur_len = PAGE_SIZE,
+		.new_val = NULL,
+		.new_len = 0,
+		.new_updated = 0,
+	};
+	struct cgroup *cgrp;
+	loff_t pos = 0;
+	int ret;
+
+	ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL);
+	if (!ctx.cur_val ||
+	    table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) {
+		/* Let BPF program decide how to proceed. */
+		ctx.cur_len = 0;
+	}
+
+	if (write && *buf && *pcount) {
+		/* BPF program should be able to override new value with a
+		 * buffer bigger than provided by user.
+		 */
+		ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL);
+		ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount);
+		if (ctx.new_val) {
+			memcpy(ctx.new_val, *buf, ctx.new_len);
+		} else {
+			/* Let BPF program decide how to proceed. */
+			ctx.new_len = 0;
+		}
+	}
+
+	rcu_read_lock();
+	cgrp = task_dfl_cgroup(current);
+	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN);
+	rcu_read_unlock();
+
+	kfree(ctx.cur_val);
+
+	if (ret == 1 && ctx.new_updated) {
+		kfree(*buf);
+		*buf = ctx.new_val;
+		*pcount = ctx.new_len;
+	} else {
+		kfree(ctx.new_val);
+	}
+
+	return ret == 1 ? 0 : -EPERM;
+}
+
+#ifdef CONFIG_NET
+static bool __cgroup_bpf_prog_array_is_empty(struct cgroup *cgrp,
+					     enum bpf_attach_type attach_type)
+{
+	struct bpf_prog_array *prog_array;
+	bool empty;
+
+	rcu_read_lock();
+	prog_array = rcu_dereference(cgrp->bpf.effective[attach_type]);
+	empty = bpf_prog_array_is_empty(prog_array);
+	rcu_read_unlock();
+
+	return empty;
+}
+
+static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen)
+{
+	if (unlikely(max_optlen < 0))
+		return -EINVAL;
+
+	if (unlikely(max_optlen > PAGE_SIZE)) {
+		/* We don't expose optvals that are greater than PAGE_SIZE
+		 * to the BPF program.
+		 */
+		max_optlen = PAGE_SIZE;
+	}
+
+	ctx->optval = kzalloc(max_optlen, GFP_USER);
+	if (!ctx->optval)
+		return -ENOMEM;
+
+	ctx->optval_end = ctx->optval + max_optlen;
+
+	return max_optlen;
+}
+
+static void sockopt_free_buf(struct bpf_sockopt_kern *ctx)
+{
+	kfree(ctx->optval);
+}
+
+int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
+				       int *optname, char __user *optval,
+				       int *optlen, char **kernel_optval)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_kern ctx = {
+		.sk = sk,
+		.level = *level,
+		.optname = *optname,
+	};
+	int ret, max_optlen;
+
+	/* Opportunistic check to see whether we have any BPF program
+	 * attached to the hook so we don't waste time allocating
+	 * memory and locking the socket.
+	 */
+	if (!cgroup_bpf_enabled ||
+	    __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_SETSOCKOPT))
+		return 0;
+
+	/* Allocate a bit more than the initial user buffer for
+	 * BPF program. The canonical use case is overriding
+	 * TCP_CONGESTION(nv) to TCP_CONGESTION(cubic).
+	 */
+	max_optlen = max_t(int, 16, *optlen);
+
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
+	if (max_optlen < 0)
+		return max_optlen;
+
+	ctx.optlen = *optlen;
+
+	if (copy_from_user(ctx.optval, optval, min(*optlen, max_optlen)) != 0) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	lock_sock(sk);
+	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[BPF_CGROUP_SETSOCKOPT],
+				 &ctx, BPF_PROG_RUN);
+	release_sock(sk);
+
+	if (!ret) {
+		ret = -EPERM;
+		goto out;
+	}
+
+	if (ctx.optlen == -1) {
+		/* optlen set to -1, bypass kernel */
+		ret = 1;
+	} else if (ctx.optlen > max_optlen || ctx.optlen < -1) {
+		/* optlen is out of bounds */
+		ret = -EFAULT;
+	} else {
+		/* optlen within bounds, run kernel handler */
+		ret = 0;
+
+		/* export any potential modifications */
+		*level = ctx.level;
+		*optname = ctx.optname;
+
+		/* optlen == 0 from BPF indicates that we should
+		 * use original userspace data.
+		 */
+		if (ctx.optlen != 0) {
+			*optlen = ctx.optlen;
+			*kernel_optval = ctx.optval;
+			/* export and don't free sockopt buf */
+			return 0;
+		}
+	}
+
+out:
+	sockopt_free_buf(&ctx);
+	return ret;
+}
+
+int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
+				       int optname, char __user *optval,
+				       int __user *optlen, int max_optlen,
+				       int retval)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_kern ctx = {
+		.sk = sk,
+		.level = level,
+		.optname = optname,
+		.retval = retval,
+	};
+	int ret;
+
+	/* Opportunistic check to see whether we have any BPF program
+	 * attached to the hook so we don't waste time allocating
+	 * memory and locking the socket.
+	 */
+	if (!cgroup_bpf_enabled ||
+	    __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_GETSOCKOPT))
+		return retval;
+
+	ctx.optlen = max_optlen;
+
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
+	if (max_optlen < 0)
+		return max_optlen;
+
+	if (!retval) {
+		/* If kernel getsockopt finished successfully,
+		 * copy whatever was returned to the user back
+		 * into our temporary buffer. Set optlen to the
+		 * one that kernel returned as well to let
+		 * BPF programs inspect the value.
+		 */
+
+		if (get_user(ctx.optlen, optlen)) {
+			ret = -EFAULT;
+			goto out;
+		}
+
+		if (ctx.optlen < 0) {
+			ret = -EFAULT;
+			goto out;
+		}
+
+		if (copy_from_user(ctx.optval, optval,
+				   min(ctx.optlen, max_optlen)) != 0) {
+			ret = -EFAULT;
+			goto out;
+		}
+	}
+
+	lock_sock(sk);
+	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[BPF_CGROUP_GETSOCKOPT],
+				 &ctx, BPF_PROG_RUN);
+	release_sock(sk);
+
+	if (!ret) {
+		ret = -EPERM;
+		goto out;
+	}
+
+	if (optval && (ctx.optlen > max_optlen || ctx.optlen < 0)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	/* BPF programs only allowed to set retval to 0, not some
+	 * arbitrary value.
+	 */
+	if (ctx.retval != 0 && ctx.retval != retval) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	if (ctx.optlen != 0) {
+		if (optval && copy_to_user(optval, ctx.optval, ctx.optlen)) {
+			ret = -EFAULT;
+			goto out;
+		}
+		if (put_user(ctx.optlen, optlen)) {
+			ret = -EFAULT;
+			goto out;
+		}
+	}
+
+	ret = ctx.retval;
+
+out:
+	sockopt_free_buf(&ctx);
+	return ret;
+}
+
+int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
+					    int optname, void *optval,
+					    int *optlen, int retval)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_kern ctx = {
+		.sk = sk,
+		.level = level,
+		.optname = optname,
+		.retval = retval,
+		.optlen = *optlen,
+		.optval = optval,
+		.optval_end = optval + *optlen,
+	};
+	int ret;
+
+	/* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy
+	 * user data back into BPF buffer when reval != 0. This is
+	 * done as an optimization to avoid extra copy, assuming
+	 * kernel won't populate the data in case of an error.
+	 * Here we always pass the data and memset() should
+	 * be called if that data shouldn't be "exported".
+	 */
+
+	ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[BPF_CGROUP_GETSOCKOPT],
+				 &ctx, BPF_PROG_RUN);
+	if (!ret)
+		return -EPERM;
+
+	if (ctx.optlen > *optlen)
+		return -EFAULT;
+
+	/* BPF programs only allowed to set retval to 0, not some
+	 * arbitrary value.
+	 */
+	if (ctx.retval != 0 && ctx.retval != retval)
+		return -EFAULT;
+
+	/* BPF programs can shrink the buffer, export the modifications.
+	 */
+	if (ctx.optlen != 0)
+		*optlen = ctx.optlen;
+
+	return ctx.retval;
+}
+#endif
+
+static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp,
+			      size_t *lenp)
+{
+	ssize_t tmp_ret = 0, ret;
+
+	if (dir->header.parent) {
+		tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp);
+		if (tmp_ret < 0)
+			return tmp_ret;
+	}
+
+	ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp);
+	if (ret < 0)
+		return ret;
+	*bufp += ret;
+	*lenp -= ret;
+	ret += tmp_ret;
+
+	/* Avoid leading slash. */
+	if (!ret)
+		return ret;
+
+	tmp_ret = strscpy(*bufp, "/", *lenp);
+	if (tmp_ret < 0)
+		return tmp_ret;
+	*bufp += tmp_ret;
+	*lenp -= tmp_ret;
+
+	return ret + tmp_ret;
+}
+
+BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf,
+	   size_t, buf_len, u64, flags)
+{
+	ssize_t tmp_ret = 0, ret;
+
+	if (!buf)
+		return -EINVAL;
+
+	if (!(flags & BPF_F_SYSCTL_BASE_NAME)) {
+		if (!ctx->head)
+			return -EINVAL;
+		tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len);
+		if (tmp_ret < 0)
+			return tmp_ret;
+	}
+
+	ret = strscpy(buf, ctx->table->procname, buf_len);
+
+	return ret < 0 ? ret : tmp_ret + ret;
+}
+
+static const struct bpf_func_proto bpf_sysctl_get_name_proto = {
+	.func		= bpf_sysctl_get_name,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+static int copy_sysctl_value(char *dst, size_t dst_len, char *src,
+			     size_t src_len)
+{
+	if (!dst)
+		return -EINVAL;
+
+	if (!dst_len)
+		return -E2BIG;
+
+	if (!src || !src_len) {
+		memset(dst, 0, dst_len);
+		return -EINVAL;
+	}
+
+	memcpy(dst, src, min(dst_len, src_len));
+
+	if (dst_len > src_len) {
+		memset(dst + src_len, '\0', dst_len - src_len);
+		return src_len;
+	}
+
+	dst[dst_len - 1] = '\0';
+
+	return -E2BIG;
+}
+
+BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx,
+	   char *, buf, size_t, buf_len)
+{
+	return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len);
+}
+
+static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = {
+	.func		= bpf_sysctl_get_current_value,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf,
+	   size_t, buf_len)
+{
+	if (!ctx->write) {
+		if (buf && buf_len)
+			memset(buf, '\0', buf_len);
+		return -EINVAL;
+	}
+	return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len);
+}
+
+static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = {
+	.func		= bpf_sysctl_get_new_value,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx,
+	   const char *, buf, size_t, buf_len)
+{
+	if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len)
+		return -EINVAL;
+
+	if (buf_len > PAGE_SIZE - 1)
+		return -E2BIG;
+
+	memcpy(ctx->new_val, buf, buf_len);
+	ctx->new_len = buf_len;
+	ctx->new_updated = 1;
+
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = {
+	.func		= bpf_sysctl_set_new_value,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+static const struct bpf_func_proto *
+sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_strtol:
+		return &bpf_strtol_proto;
+	case BPF_FUNC_strtoul:
+		return &bpf_strtoul_proto;
+	case BPF_FUNC_sysctl_get_name:
+		return &bpf_sysctl_get_name_proto;
+	case BPF_FUNC_sysctl_get_current_value:
+		return &bpf_sysctl_get_current_value_proto;
+	case BPF_FUNC_sysctl_get_new_value:
+		return &bpf_sysctl_get_new_value_proto;
+	case BPF_FUNC_sysctl_set_new_value:
+		return &bpf_sysctl_set_new_value_proto;
+	default:
+		return cgroup_base_func_proto(func_id, prog);
+	}
+}
+
+static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type,
+				   const struct bpf_prog *prog,
+				   struct bpf_insn_access_aux *info)
+{
+	const int size_default = sizeof(__u32);
+
+	if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size)
+		return false;
+
+	switch (off) {
+	case bpf_ctx_range(struct bpf_sysctl, write):
+		if (type != BPF_READ)
+			return false;
+		bpf_ctx_record_field_size(info, size_default);
+		return bpf_ctx_narrow_access_ok(off, size, size_default);
+	case bpf_ctx_range(struct bpf_sysctl, file_pos):
+		if (type == BPF_READ) {
+			bpf_ctx_record_field_size(info, size_default);
+			return bpf_ctx_narrow_access_ok(off, size, size_default);
+		} else {
+			return size == size_default;
+		}
+	default:
+		return false;
+	}
+}
+
+static u32 sysctl_convert_ctx_access(enum bpf_access_type type,
+				     const struct bpf_insn *si,
+				     struct bpf_insn *insn_buf,
+				     struct bpf_prog *prog, u32 *target_size)
+{
+	struct bpf_insn *insn = insn_buf;
+	u32 read_size;
+
+	switch (si->off) {
+	case offsetof(struct bpf_sysctl, write):
+		*insn++ = BPF_LDX_MEM(
+			BPF_SIZE(si->code), si->dst_reg, si->src_reg,
+			bpf_target_off(struct bpf_sysctl_kern, write,
+				       sizeof_field(struct bpf_sysctl_kern,
+						    write),
+				       target_size));
+		break;
+	case offsetof(struct bpf_sysctl, file_pos):
+		/* ppos is a pointer so it should be accessed via indirect
+		 * loads and stores. Also for stores additional temporary
+		 * register is used since neither src_reg nor dst_reg can be
+		 * overridden.
+		 */
+		if (type == BPF_WRITE) {
+			int treg = BPF_REG_9;
+
+			if (si->src_reg == treg || si->dst_reg == treg)
+				--treg;
+			if (si->src_reg == treg || si->dst_reg == treg)
+				--treg;
+			*insn++ = BPF_STX_MEM(
+				BPF_DW, si->dst_reg, treg,
+				offsetof(struct bpf_sysctl_kern, tmp_reg));
+			*insn++ = BPF_LDX_MEM(
+				BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
+				treg, si->dst_reg,
+				offsetof(struct bpf_sysctl_kern, ppos));
+			*insn++ = BPF_STX_MEM(
+				BPF_SIZEOF(u32), treg, si->src_reg,
+				bpf_ctx_narrow_access_offset(
+					0, sizeof(u32), sizeof(loff_t)));
+			*insn++ = BPF_LDX_MEM(
+				BPF_DW, treg, si->dst_reg,
+				offsetof(struct bpf_sysctl_kern, tmp_reg));
+		} else {
+			*insn++ = BPF_LDX_MEM(
+				BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
+				si->dst_reg, si->src_reg,
+				offsetof(struct bpf_sysctl_kern, ppos));
+			read_size = bpf_size_to_bytes(BPF_SIZE(si->code));
+			*insn++ = BPF_LDX_MEM(
+				BPF_SIZE(si->code), si->dst_reg, si->dst_reg,
+				bpf_ctx_narrow_access_offset(
+					0, read_size, sizeof(loff_t)));
+		}
+		*target_size = sizeof(u32);
+		break;
+	}
+
+	return insn - insn_buf;
+}
+
+const struct bpf_verifier_ops cg_sysctl_verifier_ops = {
+	.get_func_proto		= sysctl_func_proto,
+	.is_valid_access	= sysctl_is_valid_access,
+	.convert_ctx_access	= sysctl_convert_ctx_access,
+};
+
+const struct bpf_prog_ops cg_sysctl_prog_ops = {
+};
+
+static const struct bpf_func_proto *
+cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+#ifdef CONFIG_NET
+	case BPF_FUNC_sk_storage_get:
+		return &bpf_sk_storage_get_proto;
+	case BPF_FUNC_sk_storage_delete:
+		return &bpf_sk_storage_delete_proto;
+#endif
+#ifdef CONFIG_INET
+	case BPF_FUNC_tcp_sock:
+		return &bpf_tcp_sock_proto;
+#endif
+	default:
+		return cgroup_base_func_proto(func_id, prog);
+	}
+}
+
+static bool cg_sockopt_is_valid_access(int off, int size,
+				       enum bpf_access_type type,
+				       const struct bpf_prog *prog,
+				       struct bpf_insn_access_aux *info)
+{
+	const int size_default = sizeof(__u32);
+
+	if (off < 0 || off >= sizeof(struct bpf_sockopt))
+		return false;
+
+	if (off % size != 0)
+		return false;
+
+	if (type == BPF_WRITE) {
+		switch (off) {
+		case offsetof(struct bpf_sockopt, retval):
+			if (size != size_default)
+				return false;
+			return prog->expected_attach_type ==
+				BPF_CGROUP_GETSOCKOPT;
+		case offsetof(struct bpf_sockopt, optname):
+			fallthrough;
+		case offsetof(struct bpf_sockopt, level):
+			if (size != size_default)
+				return false;
+			return prog->expected_attach_type ==
+				BPF_CGROUP_SETSOCKOPT;
+		case offsetof(struct bpf_sockopt, optlen):
+			return size == size_default;
+		default:
+			return false;
+		}
+	}
+
+	switch (off) {
+	case offsetof(struct bpf_sockopt, sk):
+		if (size != sizeof(__u64))
+			return false;
+		info->reg_type = PTR_TO_SOCKET;
+		break;
+	case offsetof(struct bpf_sockopt, optval):
+		if (size != sizeof(__u64))
+			return false;
+		info->reg_type = PTR_TO_PACKET;
+		break;
+	case offsetof(struct bpf_sockopt, optval_end):
+		if (size != sizeof(__u64))
+			return false;
+		info->reg_type = PTR_TO_PACKET_END;
+		break;
+	case offsetof(struct bpf_sockopt, retval):
+		if (size != size_default)
+			return false;
+		return prog->expected_attach_type == BPF_CGROUP_GETSOCKOPT;
+	default:
+		if (size != size_default)
+			return false;
+		break;
+	}
+	return true;
+}
+
+#define CG_SOCKOPT_ACCESS_FIELD(T, F)					\
+	T(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F),			\
+	  si->dst_reg, si->src_reg,					\
+	  offsetof(struct bpf_sockopt_kern, F))
+
+static u32 cg_sockopt_convert_ctx_access(enum bpf_access_type type,
+					 const struct bpf_insn *si,
+					 struct bpf_insn *insn_buf,
+					 struct bpf_prog *prog,
+					 u32 *target_size)
+{
+	struct bpf_insn *insn = insn_buf;
+
+	switch (si->off) {
+	case offsetof(struct bpf_sockopt, sk):
+		*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, sk);
+		break;
+	case offsetof(struct bpf_sockopt, level):
+		if (type == BPF_WRITE)
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, level);
+		else
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, level);
+		break;
+	case offsetof(struct bpf_sockopt, optname):
+		if (type == BPF_WRITE)
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optname);
+		else
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optname);
+		break;
+	case offsetof(struct bpf_sockopt, optlen):
+		if (type == BPF_WRITE)
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optlen);
+		else
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optlen);
+		break;
+	case offsetof(struct bpf_sockopt, retval):
+		if (type == BPF_WRITE)
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, retval);
+		else
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, retval);
+		break;
+	case offsetof(struct bpf_sockopt, optval):
+		*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval);
+		break;
+	case offsetof(struct bpf_sockopt, optval_end):
+		*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval_end);
+		break;
+	}
+
+	return insn - insn_buf;
+}
+
+static int cg_sockopt_get_prologue(struct bpf_insn *insn_buf,
+				   bool direct_write,
+				   const struct bpf_prog *prog)
+{
+	/* Nothing to do for sockopt argument. The data is kzalloc'ated.
+	 */
+	return 0;
+}
+
+const struct bpf_verifier_ops cg_sockopt_verifier_ops = {
+	.get_func_proto		= cg_sockopt_func_proto,
+	.is_valid_access	= cg_sockopt_is_valid_access,
+	.convert_ctx_access	= cg_sockopt_convert_ctx_access,
+	.gen_prologue		= cg_sockopt_get_prologue,
+};
+
+const struct bpf_prog_ops cg_sockopt_prog_ops = {
+};