summaryrefslogtreecommitdiffstats
path: root/kernel/bpf/cgroup.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--kernel/bpf/cgroup.c2582
1 files changed, 2582 insertions, 0 deletions
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
new file mode 100644
index 0000000000..ac37bd53ae
--- /dev/null
+++ b/kernel/bpf/cgroup.c
@@ -0,0 +1,2582 @@
+// 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 <linux/bpf_lsm.h>
+#include <linux/bpf_verifier.h>
+#include <net/sock.h>
+#include <net/bpf_sk_storage.h>
+
+#include "../cgroup/cgroup-internal.h"
+
+DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE);
+EXPORT_SYMBOL(cgroup_bpf_enabled_key);
+
+/* __always_inline is necessary to prevent indirect call through run_prog
+ * function pointer.
+ */
+static __always_inline int
+bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
+ enum cgroup_bpf_attach_type atype,
+ const void *ctx, bpf_prog_run_fn run_prog,
+ int retval, u32 *ret_flags)
+{
+ const struct bpf_prog_array_item *item;
+ const struct bpf_prog *prog;
+ const struct bpf_prog_array *array;
+ struct bpf_run_ctx *old_run_ctx;
+ struct bpf_cg_run_ctx run_ctx;
+ u32 func_ret;
+
+ run_ctx.retval = retval;
+ migrate_disable();
+ rcu_read_lock();
+ array = rcu_dereference(cgrp->effective[atype]);
+ item = &array->items[0];
+ old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
+ while ((prog = READ_ONCE(item->prog))) {
+ run_ctx.prog_item = item;
+ func_ret = run_prog(prog, ctx);
+ if (ret_flags) {
+ *(ret_flags) |= (func_ret >> 1);
+ func_ret &= 1;
+ }
+ if (!func_ret && !IS_ERR_VALUE((long)run_ctx.retval))
+ run_ctx.retval = -EPERM;
+ item++;
+ }
+ bpf_reset_run_ctx(old_run_ctx);
+ rcu_read_unlock();
+ migrate_enable();
+ return run_ctx.retval;
+}
+
+unsigned int __cgroup_bpf_run_lsm_sock(const void *ctx,
+ const struct bpf_insn *insn)
+{
+ const struct bpf_prog *shim_prog;
+ struct sock *sk;
+ struct cgroup *cgrp;
+ int ret = 0;
+ u64 *args;
+
+ args = (u64 *)ctx;
+ sk = (void *)(unsigned long)args[0];
+ /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
+ shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
+
+ cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+ if (likely(cgrp))
+ ret = bpf_prog_run_array_cg(&cgrp->bpf,
+ shim_prog->aux->cgroup_atype,
+ ctx, bpf_prog_run, 0, NULL);
+ return ret;
+}
+
+unsigned int __cgroup_bpf_run_lsm_socket(const void *ctx,
+ const struct bpf_insn *insn)
+{
+ const struct bpf_prog *shim_prog;
+ struct socket *sock;
+ struct cgroup *cgrp;
+ int ret = 0;
+ u64 *args;
+
+ args = (u64 *)ctx;
+ sock = (void *)(unsigned long)args[0];
+ /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
+ shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
+
+ cgrp = sock_cgroup_ptr(&sock->sk->sk_cgrp_data);
+ if (likely(cgrp))
+ ret = bpf_prog_run_array_cg(&cgrp->bpf,
+ shim_prog->aux->cgroup_atype,
+ ctx, bpf_prog_run, 0, NULL);
+ return ret;
+}
+
+unsigned int __cgroup_bpf_run_lsm_current(const void *ctx,
+ const struct bpf_insn *insn)
+{
+ const struct bpf_prog *shim_prog;
+ struct cgroup *cgrp;
+ int ret = 0;
+
+ /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
+ shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
+
+ /* We rely on trampoline's __bpf_prog_enter_lsm_cgroup to grab RCU read lock. */
+ cgrp = task_dfl_cgroup(current);
+ if (likely(cgrp))
+ ret = bpf_prog_run_array_cg(&cgrp->bpf,
+ shim_prog->aux->cgroup_atype,
+ ctx, bpf_prog_run, 0, NULL);
+ return ret;
+}
+
+#ifdef CONFIG_BPF_LSM
+struct cgroup_lsm_atype {
+ u32 attach_btf_id;
+ int refcnt;
+};
+
+static struct cgroup_lsm_atype cgroup_lsm_atype[CGROUP_LSM_NUM];
+
+static enum cgroup_bpf_attach_type
+bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id)
+{
+ int i;
+
+ lockdep_assert_held(&cgroup_mutex);
+
+ if (attach_type != BPF_LSM_CGROUP)
+ return to_cgroup_bpf_attach_type(attach_type);
+
+ for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++)
+ if (cgroup_lsm_atype[i].attach_btf_id == attach_btf_id)
+ return CGROUP_LSM_START + i;
+
+ for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++)
+ if (cgroup_lsm_atype[i].attach_btf_id == 0)
+ return CGROUP_LSM_START + i;
+
+ return -E2BIG;
+
+}
+
+void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype)
+{
+ int i = cgroup_atype - CGROUP_LSM_START;
+
+ lockdep_assert_held(&cgroup_mutex);
+
+ WARN_ON_ONCE(cgroup_lsm_atype[i].attach_btf_id &&
+ cgroup_lsm_atype[i].attach_btf_id != attach_btf_id);
+
+ cgroup_lsm_atype[i].attach_btf_id = attach_btf_id;
+ cgroup_lsm_atype[i].refcnt++;
+}
+
+void bpf_cgroup_atype_put(int cgroup_atype)
+{
+ int i = cgroup_atype - CGROUP_LSM_START;
+
+ cgroup_lock();
+ if (--cgroup_lsm_atype[i].refcnt <= 0)
+ cgroup_lsm_atype[i].attach_btf_id = 0;
+ WARN_ON_ONCE(cgroup_lsm_atype[i].refcnt < 0);
+ cgroup_unlock();
+}
+#else
+static enum cgroup_bpf_attach_type
+bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id)
+{
+ if (attach_type != BPF_LSM_CGROUP)
+ return to_cgroup_bpf_attach_type(attach_type);
+ return -EOPNOTSUPP;
+}
+#endif /* CONFIG_BPF_LSM */
+
+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 atype;
+
+ cgroup_lock();
+
+ for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) {
+ struct hlist_head *progs = &cgrp->bpf.progs[atype];
+ struct bpf_prog_list *pl;
+ struct hlist_node *pltmp;
+
+ hlist_for_each_entry_safe(pl, pltmp, progs, node) {
+ hlist_del(&pl->node);
+ if (pl->prog) {
+ if (pl->prog->expected_attach_type == BPF_LSM_CGROUP)
+ bpf_trampoline_unlink_cgroup_shim(pl->prog);
+ bpf_prog_put(pl->prog);
+ }
+ if (pl->link) {
+ if (pl->link->link.prog->expected_attach_type == BPF_LSM_CGROUP)
+ bpf_trampoline_unlink_cgroup_shim(pl->link->link.prog);
+ bpf_cgroup_link_auto_detach(pl->link);
+ }
+ kfree(pl);
+ static_branch_dec(&cgroup_bpf_enabled_key[atype]);
+ }
+ old_array = rcu_dereference_protected(
+ cgrp->bpf.effective[atype],
+ 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);
+ }
+
+ cgroup_unlock();
+
+ 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 hlist_head *head)
+{
+ struct bpf_prog_list *pl;
+ u32 cnt = 0;
+
+ hlist_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 cgroup_bpf_attach_type atype)
+{
+ struct cgroup *p;
+
+ p = cgroup_parent(cgrp);
+ if (!p)
+ return true;
+ do {
+ u32 flags = p->bpf.flags[atype];
+ u32 cnt;
+
+ if (flags & BPF_F_ALLOW_MULTI)
+ return true;
+ cnt = prog_list_length(&p->bpf.progs[atype]);
+ 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 cgroup_bpf_attach_type atype,
+ 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[atype] & BPF_F_ALLOW_MULTI))
+ cnt += prog_list_length(&p->bpf.progs[atype]);
+ 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[atype] & BPF_F_ALLOW_MULTI))
+ continue;
+
+ hlist_for_each_entry(pl, &p->bpf.progs[atype], 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 cgroup_bpf_attach_type atype,
+ struct bpf_prog_array *old_array)
+{
+ old_array = rcu_replace_pointer(cgrp->bpf.effective[atype], 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_HLIST_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 cgroup_bpf_attach_type atype)
+{
+ 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, atype, &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, atype, 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 hlist_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 (hlist_empty(progs))
+ return NULL;
+ return hlist_entry(progs->first, typeof(*pl), node);
+ }
+
+ hlist_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) {
+ hlist_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.
+ */
+static 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 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 *new_prog = prog ? : link->link.prog;
+ enum cgroup_bpf_attach_type atype;
+ struct bpf_prog_list *pl;
+ struct hlist_head *progs;
+ 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;
+
+ atype = bpf_cgroup_atype_find(type, new_prog->aux->attach_btf_id);
+ if (atype < 0)
+ return -EINVAL;
+
+ progs = &cgrp->bpf.progs[atype];
+
+ if (!hierarchy_allows_attach(cgrp, atype))
+ return -EPERM;
+
+ if (!hlist_empty(progs) && cgrp->bpf.flags[atype] != 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 {
+ struct hlist_node *last = NULL;
+
+ pl = kmalloc(sizeof(*pl), GFP_KERNEL);
+ if (!pl) {
+ bpf_cgroup_storages_free(new_storage);
+ return -ENOMEM;
+ }
+ if (hlist_empty(progs))
+ hlist_add_head(&pl->node, progs);
+ else
+ hlist_for_each(last, progs) {
+ if (last->next)
+ continue;
+ hlist_add_behind(&pl->node, last);
+ break;
+ }
+ }
+
+ pl->prog = prog;
+ pl->link = link;
+ bpf_cgroup_storages_assign(pl->storage, storage);
+ cgrp->bpf.flags[atype] = saved_flags;
+
+ if (type == BPF_LSM_CGROUP) {
+ err = bpf_trampoline_link_cgroup_shim(new_prog, atype);
+ if (err)
+ goto cleanup;
+ }
+
+ err = update_effective_progs(cgrp, atype);
+ if (err)
+ goto cleanup_trampoline;
+
+ if (old_prog) {
+ if (type == BPF_LSM_CGROUP)
+ bpf_trampoline_unlink_cgroup_shim(old_prog);
+ bpf_prog_put(old_prog);
+ } else {
+ static_branch_inc(&cgroup_bpf_enabled_key[atype]);
+ }
+ bpf_cgroup_storages_link(new_storage, cgrp, type);
+ return 0;
+
+cleanup_trampoline:
+ if (type == BPF_LSM_CGROUP)
+ bpf_trampoline_unlink_cgroup_shim(new_prog);
+
+cleanup:
+ if (old_prog) {
+ pl->prog = old_prog;
+ pl->link = NULL;
+ }
+ bpf_cgroup_storages_free(new_storage);
+ if (!old_prog) {
+ hlist_del(&pl->node);
+ kfree(pl);
+ }
+ return err;
+}
+
+static 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)
+{
+ int ret;
+
+ cgroup_lock();
+ ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags);
+ cgroup_unlock();
+ return ret;
+}
+
+/* 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 cgroup_bpf_attach_type atype,
+ 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 hlist_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[atype] & BPF_F_ALLOW_MULTI))
+ continue;
+
+ head = &cg->bpf.progs[atype];
+ hlist_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[atype],
+ 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
+ * @new_prog: &struct bpf_prog for the target BPF program with its refcnt
+ * incremented
+ *
+ * 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)
+{
+ enum cgroup_bpf_attach_type atype;
+ struct bpf_prog *old_prog;
+ struct bpf_prog_list *pl;
+ struct hlist_head *progs;
+ bool found = false;
+
+ atype = bpf_cgroup_atype_find(link->type, new_prog->aux->attach_btf_id);
+ if (atype < 0)
+ return -EINVAL;
+
+ progs = &cgrp->bpf.progs[atype];
+
+ if (link->link.prog->type != new_prog->type)
+ return -EINVAL;
+
+ hlist_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, atype, 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);
+
+ cgroup_lock();
+ /* 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:
+ cgroup_unlock();
+ return ret;
+}
+
+static struct bpf_prog_list *find_detach_entry(struct hlist_head *progs,
+ struct bpf_prog *prog,
+ struct bpf_cgroup_link *link,
+ bool allow_multi)
+{
+ struct bpf_prog_list *pl;
+
+ if (!allow_multi) {
+ if (hlist_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 hlist_entry(progs->first, 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 */
+ hlist_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
+ * @atype: Type of detach operation
+ */
+static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog,
+ struct bpf_cgroup_link *link,
+ enum cgroup_bpf_attach_type atype)
+{
+ struct cgroup_subsys_state *css;
+ struct bpf_prog_array *progs;
+ struct bpf_prog_list *pl;
+ struct hlist_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[atype] & BPF_F_ALLOW_MULTI))
+ continue;
+
+ head = &cg->bpf.progs[atype];
+ hlist_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[atype],
+ 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
+ * @link: 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.
+ */
+static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+ struct bpf_cgroup_link *link, enum bpf_attach_type type)
+{
+ enum cgroup_bpf_attach_type atype;
+ struct bpf_prog *old_prog;
+ struct bpf_prog_list *pl;
+ struct hlist_head *progs;
+ u32 attach_btf_id = 0;
+ u32 flags;
+
+ if (prog)
+ attach_btf_id = prog->aux->attach_btf_id;
+ if (link)
+ attach_btf_id = link->link.prog->aux->attach_btf_id;
+
+ atype = bpf_cgroup_atype_find(type, attach_btf_id);
+ if (atype < 0)
+ return -EINVAL;
+
+ progs = &cgrp->bpf.progs[atype];
+ flags = cgrp->bpf.flags[atype];
+
+ 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, atype)) {
+ /* 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, atype);
+ }
+
+ /* now can actually delete it from this cgroup list */
+ hlist_del(&pl->node);
+
+ kfree(pl);
+ if (hlist_empty(progs))
+ /* last program was detached, reset flags to zero */
+ cgrp->bpf.flags[atype] = 0;
+ if (old_prog) {
+ if (type == BPF_LSM_CGROUP)
+ bpf_trampoline_unlink_cgroup_shim(old_prog);
+ bpf_prog_put(old_prog);
+ }
+ static_branch_dec(&cgroup_bpf_enabled_key[atype]);
+ return 0;
+}
+
+static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+ enum bpf_attach_type type)
+{
+ int ret;
+
+ cgroup_lock();
+ ret = __cgroup_bpf_detach(cgrp, prog, NULL, type);
+ cgroup_unlock();
+ return ret;
+}
+
+/* Must be called with cgroup_mutex held to avoid races. */
+static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ __u32 __user *prog_attach_flags = u64_to_user_ptr(attr->query.prog_attach_flags);
+ bool effective_query = attr->query.query_flags & BPF_F_QUERY_EFFECTIVE;
+ __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+ enum bpf_attach_type type = attr->query.attach_type;
+ enum cgroup_bpf_attach_type from_atype, to_atype;
+ enum cgroup_bpf_attach_type atype;
+ struct bpf_prog_array *effective;
+ int cnt, ret = 0, i;
+ int total_cnt = 0;
+ u32 flags;
+
+ if (effective_query && prog_attach_flags)
+ return -EINVAL;
+
+ if (type == BPF_LSM_CGROUP) {
+ if (!effective_query && attr->query.prog_cnt &&
+ prog_ids && !prog_attach_flags)
+ return -EINVAL;
+
+ from_atype = CGROUP_LSM_START;
+ to_atype = CGROUP_LSM_END;
+ flags = 0;
+ } else {
+ from_atype = to_cgroup_bpf_attach_type(type);
+ if (from_atype < 0)
+ return -EINVAL;
+ to_atype = from_atype;
+ flags = cgrp->bpf.flags[from_atype];
+ }
+
+ for (atype = from_atype; atype <= to_atype; atype++) {
+ if (effective_query) {
+ effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
+ lockdep_is_held(&cgroup_mutex));
+ total_cnt += bpf_prog_array_length(effective);
+ } else {
+ total_cnt += prog_list_length(&cgrp->bpf.progs[atype]);
+ }
+ }
+
+ /* always output uattr->query.attach_flags as 0 during effective query */
+ flags = effective_query ? 0 : flags;
+ if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
+ return -EFAULT;
+ if (copy_to_user(&uattr->query.prog_cnt, &total_cnt, sizeof(total_cnt)))
+ return -EFAULT;
+ if (attr->query.prog_cnt == 0 || !prog_ids || !total_cnt)
+ /* return early if user requested only program count + flags */
+ return 0;
+
+ if (attr->query.prog_cnt < total_cnt) {
+ total_cnt = attr->query.prog_cnt;
+ ret = -ENOSPC;
+ }
+
+ for (atype = from_atype; atype <= to_atype && total_cnt; atype++) {
+ if (effective_query) {
+ effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
+ lockdep_is_held(&cgroup_mutex));
+ cnt = min_t(int, bpf_prog_array_length(effective), total_cnt);
+ ret = bpf_prog_array_copy_to_user(effective, prog_ids, cnt);
+ } else {
+ struct hlist_head *progs;
+ struct bpf_prog_list *pl;
+ struct bpf_prog *prog;
+ u32 id;
+
+ progs = &cgrp->bpf.progs[atype];
+ cnt = min_t(int, prog_list_length(progs), total_cnt);
+ i = 0;
+ hlist_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;
+ }
+
+ if (prog_attach_flags) {
+ flags = cgrp->bpf.flags[atype];
+
+ for (i = 0; i < cnt; i++)
+ if (copy_to_user(prog_attach_flags + i,
+ &flags, sizeof(flags)))
+ return -EFAULT;
+ prog_attach_flags += cnt;
+ }
+ }
+
+ prog_ids += cnt;
+ total_cnt -= cnt;
+ }
+ return ret;
+}
+
+static int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ int ret;
+
+ cgroup_lock();
+ ret = __cgroup_bpf_query(cgrp, attr, uattr);
+ cgroup_unlock();
+ 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;
+
+ cgroup_lock();
+
+ /* re-check cgroup under lock again */
+ if (!cg_link->cgroup) {
+ cgroup_unlock();
+ return;
+ }
+
+ WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link,
+ cg_link->type));
+ if (cg_link->type == BPF_LSM_CGROUP)
+ bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog);
+
+ cg = cg_link->cgroup;
+ cg_link->cgroup = NULL;
+
+ cgroup_unlock();
+
+ 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;
+
+ cgroup_lock();
+ if (cg_link->cgroup)
+ cg_id = cgroup_id(cg_link->cgroup);
+ cgroup_unlock();
+
+ 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;
+
+ cgroup_lock();
+ if (cg_link->cgroup)
+ cg_id = cgroup_id(cg_link->cgroup);
+ cgroup_unlock();
+
+ 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
+ * @atype: The type of program to be executed
+ *
+ * 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
+ * -err - 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 cgroup_bpf_attach_type atype)
+{
+ 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 (atype == CGROUP_INET_EGRESS) {
+ u32 flags = 0;
+ bool cn;
+
+ ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb,
+ __bpf_prog_run_save_cb, 0, &flags);
+
+ /* Return values of CGROUP EGRESS BPF programs are:
+ * 0: drop packet
+ * 1: keep packet
+ * 2: drop packet and cn
+ * 3: keep packet and cn
+ *
+ * The returned value is then converted to one of the NET_XMIT
+ * or an error code that is then interpreted as drop packet
+ * (and no cn):
+ * 0: NET_XMIT_SUCCESS skb should be transmitted
+ * 1: NET_XMIT_DROP skb should be dropped and cn
+ * 2: NET_XMIT_CN skb should be transmitted and cn
+ * 3: -err skb should be dropped
+ */
+
+ cn = flags & BPF_RET_SET_CN;
+ if (ret && !IS_ERR_VALUE((long)ret))
+ ret = -EFAULT;
+ if (!ret)
+ ret = (cn ? NET_XMIT_CN : NET_XMIT_SUCCESS);
+ else
+ ret = (cn ? NET_XMIT_DROP : ret);
+ } else {
+ ret = bpf_prog_run_array_cg(&cgrp->bpf, atype,
+ skb, __bpf_prog_run_save_cb, 0,
+ NULL);
+ if (ret && !IS_ERR_VALUE((long)ret))
+ ret = -EFAULT;
+ }
+ 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
+ * @atype: The type of program to be executed
+ *
+ * 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 cgroup_bpf_attach_type atype)
+{
+ struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+
+ return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0,
+ NULL);
+}
+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
+ * @uaddrlen: Pointer to the size of the sockaddr struct provided by user. It is
+ * read-only for AF_INET[6] uaddr but can be modified for AF_UNIX
+ * uaddr.
+ * @atype: The type of program to be executed
+ * @t_ctx: Pointer to attach type specific context
+ * @flags: Pointer to u32 which contains higher bits of BPF program
+ * return value (OR'ed together).
+ *
+ * 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,
+ int *uaddrlen,
+ enum cgroup_bpf_attach_type atype,
+ void *t_ctx,
+ u32 *flags)
+{
+ 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;
+ ctx.uaddrlen = 0;
+ } else {
+ ctx.uaddrlen = *uaddrlen;
+ }
+
+ cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+ ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run,
+ 0, flags);
+
+ if (!ret && uaddr)
+ *uaddrlen = ctx.uaddrlen;
+
+ return ret;
+}
+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.
+ * @atype: The type of program to be executed
+ *
+ * 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 cgroup_bpf_attach_type atype)
+{
+ struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+
+ return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run,
+ 0, NULL);
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops);
+
+int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
+ short access, enum cgroup_bpf_attach_type atype)
+{
+ struct cgroup *cgrp;
+ struct bpf_cgroup_dev_ctx ctx = {
+ .access_type = (access << 16) | dev_type,
+ .major = major,
+ .minor = minor,
+ };
+ int ret;
+
+ rcu_read_lock();
+ cgrp = task_dfl_cgroup(current);
+ ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
+ NULL);
+ rcu_read_unlock();
+
+ return ret;
+}
+
+BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
+{
+ /* flags argument is not used now,
+ * but provides an ability to extend the API.
+ * verifier checks that its value is correct.
+ */
+ enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
+ struct bpf_cgroup_storage *storage;
+ struct bpf_cg_run_ctx *ctx;
+ void *ptr;
+
+ /* get current cgroup storage from BPF run context */
+ ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
+ storage = ctx->prog_item->cgroup_storage[stype];
+
+ if (stype == BPF_CGROUP_STORAGE_SHARED)
+ ptr = &READ_ONCE(storage->buf)->data[0];
+ else
+ ptr = this_cpu_ptr(storage->percpu_buf);
+
+ return (unsigned long)ptr;
+}
+
+const struct bpf_func_proto bpf_get_local_storage_proto = {
+ .func = bpf_get_local_storage,
+ .gpl_only = false,
+ .ret_type = RET_PTR_TO_MAP_VALUE,
+ .arg1_type = ARG_CONST_MAP_PTR,
+ .arg2_type = ARG_ANYTHING,
+};
+
+BPF_CALL_0(bpf_get_retval)
+{
+ struct bpf_cg_run_ctx *ctx =
+ container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
+
+ return ctx->retval;
+}
+
+const struct bpf_func_proto bpf_get_retval_proto = {
+ .func = bpf_get_retval,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+};
+
+BPF_CALL_1(bpf_set_retval, int, retval)
+{
+ struct bpf_cg_run_ctx *ctx =
+ container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
+
+ ctx->retval = retval;
+ return 0;
+}
+
+const struct bpf_func_proto bpf_set_retval_proto = {
+ .func = bpf_set_retval,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *
+cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+ const struct bpf_func_proto *func_proto;
+
+ func_proto = cgroup_common_func_proto(func_id, prog);
+ if (func_proto)
+ return func_proto;
+
+ func_proto = cgroup_current_func_proto(func_id, prog);
+ if (func_proto)
+ return func_proto;
+
+ switch (func_id) {
+ case BPF_FUNC_perf_event_output:
+ return &bpf_event_output_data_proto;
+ default:
+ return bpf_base_func_proto(func_id);
+ }
+}
+
+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
+ * @atype: 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 cgroup_bpf_attach_type atype)
+{
+ 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_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
+ NULL);
+ 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;
+}
+
+#ifdef CONFIG_NET
+static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen,
+ struct bpf_sockopt_buf *buf)
+{
+ 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;
+ }
+
+ if (max_optlen <= sizeof(buf->data)) {
+ /* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE
+ * bytes avoid the cost of kzalloc.
+ */
+ ctx->optval = buf->data;
+ ctx->optval_end = ctx->optval + max_optlen;
+ return max_optlen;
+ }
+
+ 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,
+ struct bpf_sockopt_buf *buf)
+{
+ if (ctx->optval == buf->data)
+ return;
+ kfree(ctx->optval);
+}
+
+static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx,
+ struct bpf_sockopt_buf *buf)
+{
+ return ctx->optval != buf->data;
+}
+
+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_buf buf = {};
+ struct bpf_sockopt_kern ctx = {
+ .sk = sk,
+ .level = *level,
+ .optname = *optname,
+ };
+ int ret, max_optlen;
+
+ /* 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, &buf);
+ 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_cg(&cgrp->bpf, CGROUP_SETSOCKOPT,
+ &ctx, bpf_prog_run, 0, NULL);
+ release_sock(sk);
+
+ if (ret)
+ 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 */
+ if (*optlen > PAGE_SIZE && ctx.optlen >= 0) {
+ pr_info_once("bpf setsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n",
+ ctx.optlen, max_optlen);
+ ret = 0;
+ goto out;
+ }
+ 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;
+ /* We've used bpf_sockopt_kern->buf as an intermediary
+ * storage, but the BPF program indicates that we need
+ * to pass this data to the kernel setsockopt handler.
+ * No way to export on-stack buf, have to allocate a
+ * new buffer.
+ */
+ if (!sockopt_buf_allocated(&ctx, &buf)) {
+ void *p = kmalloc(ctx.optlen, GFP_USER);
+
+ if (!p) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ memcpy(p, ctx.optval, ctx.optlen);
+ *kernel_optval = p;
+ } else {
+ *kernel_optval = ctx.optval;
+ }
+ /* export and don't free sockopt buf */
+ return 0;
+ }
+ }
+
+out:
+ sockopt_free_buf(&ctx, &buf);
+ 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_buf buf = {};
+ struct bpf_sockopt_kern ctx = {
+ .sk = sk,
+ .level = level,
+ .optname = optname,
+ .current_task = current,
+ };
+ int orig_optlen;
+ int ret;
+
+ orig_optlen = max_optlen;
+ ctx.optlen = max_optlen;
+ max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf);
+ 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;
+ }
+ orig_optlen = ctx.optlen;
+
+ 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_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
+ &ctx, bpf_prog_run, retval, NULL);
+ release_sock(sk);
+
+ if (ret < 0)
+ goto out;
+
+ if (optval && (ctx.optlen > max_optlen || ctx.optlen < 0)) {
+ if (orig_optlen > PAGE_SIZE && ctx.optlen >= 0) {
+ pr_info_once("bpf getsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n",
+ ctx.optlen, max_optlen);
+ ret = retval;
+ goto out;
+ }
+ 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;
+ }
+ }
+
+out:
+ sockopt_free_buf(&ctx, &buf);
+ 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,
+ .optlen = *optlen,
+ .optval = optval,
+ .optval_end = optval + *optlen,
+ .current_task = current,
+ };
+ 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_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
+ &ctx, bpf_prog_run, retval, NULL);
+ if (ret < 0)
+ return ret;
+
+ if (ctx.optlen > *optlen)
+ return -EFAULT;
+
+ /* BPF programs can shrink the buffer, export the modifications.
+ */
+ if (ctx.optlen != 0)
+ *optlen = ctx.optlen;
+
+ return ret;
+}
+#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 | MEM_RDONLY,
+ .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)
+{
+ const struct bpf_func_proto *func_proto;
+
+ func_proto = cgroup_common_func_proto(func_id, prog);
+ if (func_proto)
+ return func_proto;
+
+ func_proto = cgroup_current_func_proto(func_id, prog);
+ if (func_proto)
+ return func_proto;
+
+ switch (func_id) {
+ 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;
+ case BPF_FUNC_ktime_get_coarse_ns:
+ return &bpf_ktime_get_coarse_ns_proto;
+ case BPF_FUNC_perf_event_output:
+ return &bpf_event_output_data_proto;
+ default:
+ return bpf_base_func_proto(func_id);
+ }
+}
+
+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_RAW_INSN(
+ BPF_CLASS(si->code) | BPF_MEM | BPF_SIZEOF(u32),
+ treg, si->src_reg,
+ bpf_ctx_narrow_access_offset(
+ 0, sizeof(u32), sizeof(loff_t)),
+ si->imm);
+ *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 = {
+};
+
+#ifdef CONFIG_NET
+BPF_CALL_1(bpf_get_netns_cookie_sockopt, struct bpf_sockopt_kern *, ctx)
+{
+ const struct net *net = ctx ? sock_net(ctx->sk) : &init_net;
+
+ return net->net_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = {
+ .func = bpf_get_netns_cookie_sockopt,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX_OR_NULL,
+};
+#endif
+
+static const struct bpf_func_proto *
+cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+ const struct bpf_func_proto *func_proto;
+
+ func_proto = cgroup_common_func_proto(func_id, prog);
+ if (func_proto)
+ return func_proto;
+
+ func_proto = cgroup_current_func_proto(func_id, prog);
+ if (func_proto)
+ return func_proto;
+
+ switch (func_id) {
+#ifdef CONFIG_NET
+ case BPF_FUNC_get_netns_cookie:
+ return &bpf_get_netns_cookie_sockopt_proto;
+ case BPF_FUNC_sk_storage_get:
+ return &bpf_sk_storage_get_proto;
+ case BPF_FUNC_sk_storage_delete:
+ return &bpf_sk_storage_delete_proto;
+ case BPF_FUNC_setsockopt:
+ if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT)
+ return &bpf_sk_setsockopt_proto;
+ return NULL;
+ case BPF_FUNC_getsockopt:
+ if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT)
+ return &bpf_sk_getsockopt_proto;
+ return NULL;
+#endif
+#ifdef CONFIG_INET
+ case BPF_FUNC_tcp_sock:
+ return &bpf_tcp_sock_proto;
+#endif
+ case BPF_FUNC_perf_event_output:
+ return &bpf_event_output_data_proto;
+ default:
+ return bpf_base_func_proto(func_id);
+ }
+}
+
+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_READ_FIELD(F) \
+ BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F), \
+ si->dst_reg, si->src_reg, \
+ offsetof(struct bpf_sockopt_kern, F))
+
+#define CG_SOCKOPT_WRITE_FIELD(F) \
+ BPF_RAW_INSN((BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F) | \
+ BPF_MEM | BPF_CLASS(si->code)), \
+ si->dst_reg, si->src_reg, \
+ offsetof(struct bpf_sockopt_kern, F), \
+ si->imm)
+
+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_READ_FIELD(sk);
+ break;
+ case offsetof(struct bpf_sockopt, level):
+ if (type == BPF_WRITE)
+ *insn++ = CG_SOCKOPT_WRITE_FIELD(level);
+ else
+ *insn++ = CG_SOCKOPT_READ_FIELD(level);
+ break;
+ case offsetof(struct bpf_sockopt, optname):
+ if (type == BPF_WRITE)
+ *insn++ = CG_SOCKOPT_WRITE_FIELD(optname);
+ else
+ *insn++ = CG_SOCKOPT_READ_FIELD(optname);
+ break;
+ case offsetof(struct bpf_sockopt, optlen):
+ if (type == BPF_WRITE)
+ *insn++ = CG_SOCKOPT_WRITE_FIELD(optlen);
+ else
+ *insn++ = CG_SOCKOPT_READ_FIELD(optlen);
+ break;
+ case offsetof(struct bpf_sockopt, retval):
+ BUILD_BUG_ON(offsetof(struct bpf_cg_run_ctx, run_ctx) != 0);
+
+ 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_sockopt_kern, tmp_reg));
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task),
+ treg, si->dst_reg,
+ offsetof(struct bpf_sockopt_kern, current_task));
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx),
+ treg, treg,
+ offsetof(struct task_struct, bpf_ctx));
+ *insn++ = BPF_RAW_INSN(BPF_CLASS(si->code) | BPF_MEM |
+ BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval),
+ treg, si->src_reg,
+ offsetof(struct bpf_cg_run_ctx, retval),
+ si->imm);
+ *insn++ = BPF_LDX_MEM(BPF_DW, treg, si->dst_reg,
+ offsetof(struct bpf_sockopt_kern, tmp_reg));
+ } else {
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task),
+ si->dst_reg, si->src_reg,
+ offsetof(struct bpf_sockopt_kern, current_task));
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx),
+ si->dst_reg, si->dst_reg,
+ offsetof(struct task_struct, bpf_ctx));
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval),
+ si->dst_reg, si->dst_reg,
+ offsetof(struct bpf_cg_run_ctx, retval));
+ }
+ break;
+ case offsetof(struct bpf_sockopt, optval):
+ *insn++ = CG_SOCKOPT_READ_FIELD(optval);
+ break;
+ case offsetof(struct bpf_sockopt, optval_end):
+ *insn++ = CG_SOCKOPT_READ_FIELD(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 = {
+};
+
+/* Common helpers for cgroup hooks. */
+const struct bpf_func_proto *
+cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+ switch (func_id) {
+ case BPF_FUNC_get_local_storage:
+ return &bpf_get_local_storage_proto;
+ case BPF_FUNC_get_retval:
+ switch (prog->expected_attach_type) {
+ case BPF_CGROUP_INET_INGRESS:
+ case BPF_CGROUP_INET_EGRESS:
+ case BPF_CGROUP_SOCK_OPS:
+ case BPF_CGROUP_UDP4_RECVMSG:
+ case BPF_CGROUP_UDP6_RECVMSG:
+ case BPF_CGROUP_INET4_GETPEERNAME:
+ case BPF_CGROUP_INET6_GETPEERNAME:
+ case BPF_CGROUP_INET4_GETSOCKNAME:
+ case BPF_CGROUP_INET6_GETSOCKNAME:
+ return NULL;
+ default:
+ return &bpf_get_retval_proto;
+ }
+ case BPF_FUNC_set_retval:
+ switch (prog->expected_attach_type) {
+ case BPF_CGROUP_INET_INGRESS:
+ case BPF_CGROUP_INET_EGRESS:
+ case BPF_CGROUP_SOCK_OPS:
+ case BPF_CGROUP_UDP4_RECVMSG:
+ case BPF_CGROUP_UDP6_RECVMSG:
+ case BPF_CGROUP_INET4_GETPEERNAME:
+ case BPF_CGROUP_INET6_GETPEERNAME:
+ case BPF_CGROUP_INET4_GETSOCKNAME:
+ case BPF_CGROUP_INET6_GETSOCKNAME:
+ return NULL;
+ default:
+ return &bpf_set_retval_proto;
+ }
+ default:
+ return NULL;
+ }
+}
+
+/* Common helpers for cgroup hooks with valid process context. */
+const struct bpf_func_proto *
+cgroup_current_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_current_pid_tgid:
+ return &bpf_get_current_pid_tgid_proto;
+ case BPF_FUNC_get_current_comm:
+ return &bpf_get_current_comm_proto;
+#ifdef CONFIG_CGROUP_NET_CLASSID
+ case BPF_FUNC_get_cgroup_classid:
+ return &bpf_get_cgroup_classid_curr_proto;
+#endif
+ default:
+ return NULL;
+ }
+}