// SPDX-License-Identifier: GPL-2.0-only /* Copyright (c) 2020 Facebook */ #include <linux/bpf.h> #include <linux/fs.h> #include <linux/filter.h> #include <linux/kernel.h> #include <linux/btf_ids.h> struct bpf_iter_seq_map_info { u32 map_id; }; static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos) { struct bpf_iter_seq_map_info *info = seq->private; struct bpf_map *map; map = bpf_map_get_curr_or_next(&info->map_id); if (!map) return NULL; if (*pos == 0) ++*pos; return map; } static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct bpf_iter_seq_map_info *info = seq->private; ++*pos; ++info->map_id; bpf_map_put((struct bpf_map *)v); return bpf_map_get_curr_or_next(&info->map_id); } struct bpf_iter__bpf_map { __bpf_md_ptr(struct bpf_iter_meta *, meta); __bpf_md_ptr(struct bpf_map *, map); }; DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map) static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop) { struct bpf_iter__bpf_map ctx; struct bpf_iter_meta meta; struct bpf_prog *prog; int ret = 0; ctx.meta = &meta; ctx.map = v; meta.seq = seq; prog = bpf_iter_get_info(&meta, in_stop); if (prog) ret = bpf_iter_run_prog(prog, &ctx); return ret; } static int bpf_map_seq_show(struct seq_file *seq, void *v) { return __bpf_map_seq_show(seq, v, false); } static void bpf_map_seq_stop(struct seq_file *seq, void *v) { if (!v) (void)__bpf_map_seq_show(seq, v, true); else bpf_map_put((struct bpf_map *)v); } static const struct seq_operations bpf_map_seq_ops = { .start = bpf_map_seq_start, .next = bpf_map_seq_next, .stop = bpf_map_seq_stop, .show = bpf_map_seq_show, }; BTF_ID_LIST(btf_bpf_map_id) BTF_ID(struct, bpf_map) static const struct bpf_iter_seq_info bpf_map_seq_info = { .seq_ops = &bpf_map_seq_ops, .init_seq_private = NULL, .fini_seq_private = NULL, .seq_priv_size = sizeof(struct bpf_iter_seq_map_info), }; static struct bpf_iter_reg bpf_map_reg_info = { .target = "bpf_map", .ctx_arg_info_size = 1, .ctx_arg_info = { { offsetof(struct bpf_iter__bpf_map, map), PTR_TO_BTF_ID_OR_NULL }, }, .seq_info = &bpf_map_seq_info, }; static int bpf_iter_attach_map(struct bpf_prog *prog, union bpf_iter_link_info *linfo, struct bpf_iter_aux_info *aux) { u32 key_acc_size, value_acc_size, key_size, value_size; struct bpf_map *map; bool is_percpu = false; int err = -EINVAL; if (!linfo->map.map_fd) return -EBADF; map = bpf_map_get_with_uref(linfo->map.map_fd); if (IS_ERR(map)) return PTR_ERR(map); if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) is_percpu = true; else if (map->map_type != BPF_MAP_TYPE_HASH && map->map_type != BPF_MAP_TYPE_LRU_HASH && map->map_type != BPF_MAP_TYPE_ARRAY) goto put_map; key_acc_size = prog->aux->max_rdonly_access; value_acc_size = prog->aux->max_rdwr_access; key_size = map->key_size; if (!is_percpu) value_size = map->value_size; else value_size = round_up(map->value_size, 8) * num_possible_cpus(); if (key_acc_size > key_size || value_acc_size > value_size) { err = -EACCES; goto put_map; } aux->map = map; return 0; put_map: bpf_map_put_with_uref(map); return err; } static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux) { bpf_map_put_with_uref(aux->map); } void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux, struct seq_file *seq) { seq_printf(seq, "map_id:\t%u\n", aux->map->id); } int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux, struct bpf_link_info *info) { info->iter.map.map_id = aux->map->id; return 0; } DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta, struct bpf_map *map, void *key, void *value) static const struct bpf_iter_reg bpf_map_elem_reg_info = { .target = "bpf_map_elem", .attach_target = bpf_iter_attach_map, .detach_target = bpf_iter_detach_map, .show_fdinfo = bpf_iter_map_show_fdinfo, .fill_link_info = bpf_iter_map_fill_link_info, .ctx_arg_info_size = 2, .ctx_arg_info = { { offsetof(struct bpf_iter__bpf_map_elem, key), PTR_TO_BUF | PTR_MAYBE_NULL | MEM_RDONLY }, { offsetof(struct bpf_iter__bpf_map_elem, value), PTR_TO_BUF | PTR_MAYBE_NULL }, }, }; static int __init bpf_map_iter_init(void) { int ret; bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id; ret = bpf_iter_reg_target(&bpf_map_reg_info); if (ret) return ret; return bpf_iter_reg_target(&bpf_map_elem_reg_info); } late_initcall(bpf_map_iter_init);