1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2020 Facebook */ 3 #include <linux/bpf.h> 4 #include <linux/fs.h> 5 #include <linux/filter.h> 6 #include <linux/kernel.h> 7 #include <linux/btf_ids.h> 8 9 struct bpf_iter_seq_map_info { 10 u32 map_id; 11 }; 12 13 static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos) 14 { 15 struct bpf_iter_seq_map_info *info = seq->private; 16 struct bpf_map *map; 17 18 map = bpf_map_get_curr_or_next(&info->map_id); 19 if (!map) 20 return NULL; 21 22 if (*pos == 0) 23 ++*pos; 24 return map; 25 } 26 27 static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos) 28 { 29 struct bpf_iter_seq_map_info *info = seq->private; 30 31 ++*pos; 32 ++info->map_id; 33 bpf_map_put((struct bpf_map *)v); 34 return bpf_map_get_curr_or_next(&info->map_id); 35 } 36 37 struct bpf_iter__bpf_map { 38 __bpf_md_ptr(struct bpf_iter_meta *, meta); 39 __bpf_md_ptr(struct bpf_map *, map); 40 }; 41 42 DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map) 43 44 static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop) 45 { 46 struct bpf_iter__bpf_map ctx; 47 struct bpf_iter_meta meta; 48 struct bpf_prog *prog; 49 int ret = 0; 50 51 ctx.meta = &meta; 52 ctx.map = v; 53 meta.seq = seq; 54 prog = bpf_iter_get_info(&meta, in_stop); 55 if (prog) 56 ret = bpf_iter_run_prog(prog, &ctx); 57 58 return ret; 59 } 60 61 static int bpf_map_seq_show(struct seq_file *seq, void *v) 62 { 63 return __bpf_map_seq_show(seq, v, false); 64 } 65 66 static void bpf_map_seq_stop(struct seq_file *seq, void *v) 67 { 68 if (!v) 69 (void)__bpf_map_seq_show(seq, v, true); 70 else 71 bpf_map_put((struct bpf_map *)v); 72 } 73 74 static const struct seq_operations bpf_map_seq_ops = { 75 .start = bpf_map_seq_start, 76 .next = bpf_map_seq_next, 77 .stop = bpf_map_seq_stop, 78 .show = bpf_map_seq_show, 79 }; 80 81 BTF_ID_LIST(btf_bpf_map_id) 82 BTF_ID(struct, bpf_map) 83 84 static const struct bpf_iter_seq_info bpf_map_seq_info = { 85 .seq_ops = &bpf_map_seq_ops, 86 .init_seq_private = NULL, 87 .fini_seq_private = NULL, 88 .seq_priv_size = sizeof(struct bpf_iter_seq_map_info), 89 }; 90 91 static struct bpf_iter_reg bpf_map_reg_info = { 92 .target = "bpf_map", 93 .ctx_arg_info_size = 1, 94 .ctx_arg_info = { 95 { offsetof(struct bpf_iter__bpf_map, map), 96 PTR_TO_BTF_ID_OR_NULL }, 97 }, 98 .seq_info = &bpf_map_seq_info, 99 }; 100 101 static int bpf_iter_attach_map(struct bpf_prog *prog, 102 union bpf_iter_link_info *linfo, 103 struct bpf_iter_aux_info *aux) 104 { 105 u32 key_acc_size, value_acc_size, key_size, value_size; 106 struct bpf_map *map; 107 bool is_percpu = false; 108 int err = -EINVAL; 109 110 if (!linfo->map.map_fd) 111 return -EBADF; 112 113 map = bpf_map_get_with_uref(linfo->map.map_fd); 114 if (IS_ERR(map)) 115 return PTR_ERR(map); 116 117 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 118 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || 119 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) 120 is_percpu = true; 121 else if (map->map_type != BPF_MAP_TYPE_HASH && 122 map->map_type != BPF_MAP_TYPE_LRU_HASH && 123 map->map_type != BPF_MAP_TYPE_ARRAY) 124 goto put_map; 125 126 key_acc_size = prog->aux->max_rdonly_access; 127 value_acc_size = prog->aux->max_rdwr_access; 128 key_size = map->key_size; 129 if (!is_percpu) 130 value_size = map->value_size; 131 else 132 value_size = round_up(map->value_size, 8) * num_possible_cpus(); 133 134 if (key_acc_size > key_size || value_acc_size > value_size) { 135 err = -EACCES; 136 goto put_map; 137 } 138 139 aux->map = map; 140 return 0; 141 142 put_map: 143 bpf_map_put_with_uref(map); 144 return err; 145 } 146 147 static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux) 148 { 149 bpf_map_put_with_uref(aux->map); 150 } 151 152 void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux, 153 struct seq_file *seq) 154 { 155 seq_printf(seq, "map_id:\t%u\n", aux->map->id); 156 } 157 158 int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux, 159 struct bpf_link_info *info) 160 { 161 info->iter.map.map_id = aux->map->id; 162 return 0; 163 } 164 165 DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta, 166 struct bpf_map *map, void *key, void *value) 167 168 static const struct bpf_iter_reg bpf_map_elem_reg_info = { 169 .target = "bpf_map_elem", 170 .attach_target = bpf_iter_attach_map, 171 .detach_target = bpf_iter_detach_map, 172 .show_fdinfo = bpf_iter_map_show_fdinfo, 173 .fill_link_info = bpf_iter_map_fill_link_info, 174 .ctx_arg_info_size = 2, 175 .ctx_arg_info = { 176 { offsetof(struct bpf_iter__bpf_map_elem, key), 177 PTR_TO_RDONLY_BUF_OR_NULL }, 178 { offsetof(struct bpf_iter__bpf_map_elem, value), 179 PTR_TO_RDWR_BUF_OR_NULL }, 180 }, 181 }; 182 183 static int __init bpf_map_iter_init(void) 184 { 185 int ret; 186 187 bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id; 188 ret = bpf_iter_reg_target(&bpf_map_reg_info); 189 if (ret) 190 return ret; 191 192 return bpf_iter_reg_target(&bpf_map_elem_reg_info); 193 } 194 195 late_initcall(bpf_map_iter_init); 196