| // 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; |
| |
| mutex_lock(&cgroup_mutex); |
| if (--cgroup_lsm_atype[i].refcnt <= 0) |
| cgroup_lsm_atype[i].attach_btf_id = 0; |
| WARN_ON_ONCE(cgroup_lsm_atype[i].refcnt < 0); |
| mutex_unlock(&cgroup_mutex); |
| } |
| #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; |
| |
| mutex_lock(&cgroup_mutex); |
| |
| 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); |
| } |
| |
| 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 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; |
| |
| mutex_lock(&cgroup_mutex); |
| ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags); |
| mutex_unlock(&cgroup_mutex); |
| 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 |
| * @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) |
| { |
| 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); |
| |
| 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 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++; |
| } |
| } |
| found: |
| BUG_ON(!cg); |
| 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; |
| |
| mutex_lock(&cgroup_mutex); |
| ret = __cgroup_bpf_detach(cgrp, prog, NULL, type); |
| mutex_unlock(&cgroup_mutex); |
| 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); |
| __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 (type == BPF_LSM_CGROUP) { |
| if (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 (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) { |
| 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]); |
| } |
| } |
| |
| 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 (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) { |
| 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; |
| |
| mutex_lock(&cgroup_mutex); |
| ret = __cgroup_bpf_query(cgrp, attr, uattr); |
| mutex_unlock(&cgroup_mutex); |
| 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)); |
| if (cg_link->type == BPF_LSM_CGROUP) |
| bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog); |
| |
| 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 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 |
| * @type: 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 |
| * @type: 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, |
| 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; |
| |
| /* 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); |
| return bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, |
| 0, flags); |
| } |
| 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 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_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_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; |
| case BPF_FUNC_get_retval: |
| return &bpf_get_retval_proto; |
| case BPF_FUNC_set_retval: |
| return &bpf_set_retval_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 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 */ |
| 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 ret; |
| |
| 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; |
| } |
| |
| 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 (ctx.optlen > max_optlen || ctx.optlen < 0) { |
| ret = -EFAULT; |
| goto out; |
| } |
| |
| if (ctx.optlen != 0) { |
| if (copy_to_user(optval, ctx.optval, ctx.optlen) || |
| 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) |
| { |
| 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; |
| case BPF_FUNC_ktime_get_coarse_ns: |
| return &bpf_ktime_get_coarse_ns_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 = { |
| }; |
| |
| #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) |
| { |
| 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 |
| 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): |
| 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_STX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval), |
| treg, si->src_reg, |
| offsetof(struct bpf_cg_run_ctx, retval)); |
| *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_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 = { |
| }; |