1 /* 2 * Copyright (C) 2017 Netronome Systems, Inc. 3 * 4 * This software is licensed under the GNU General License Version 2, 5 * June 1991 as shown in the file COPYING in the top-level directory of this 6 * source tree. 7 * 8 * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" 9 * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, 10 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 11 * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE 12 * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME 13 * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 14 */ 15 16 #include <linux/bpf.h> 17 #include <linux/bpf_verifier.h> 18 #include <linux/bug.h> 19 #include <linux/kdev_t.h> 20 #include <linux/list.h> 21 #include <linux/netdevice.h> 22 #include <linux/printk.h> 23 #include <linux/proc_ns.h> 24 #include <linux/rtnetlink.h> 25 #include <linux/rwsem.h> 26 27 /* Protects bpf_prog_offload_devs, bpf_map_offload_devs and offload members 28 * of all progs. 29 * RTNL lock cannot be taken when holding this lock. 30 */ 31 static DECLARE_RWSEM(bpf_devs_lock); 32 static LIST_HEAD(bpf_prog_offload_devs); 33 static LIST_HEAD(bpf_map_offload_devs); 34 35 static int bpf_dev_offload_check(struct net_device *netdev) 36 { 37 if (!netdev) 38 return -EINVAL; 39 if (!netdev->netdev_ops->ndo_bpf) 40 return -EOPNOTSUPP; 41 return 0; 42 } 43 44 int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr) 45 { 46 struct bpf_prog_offload *offload; 47 int err; 48 49 if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS && 50 attr->prog_type != BPF_PROG_TYPE_XDP) 51 return -EINVAL; 52 53 if (attr->prog_flags) 54 return -EINVAL; 55 56 offload = kzalloc(sizeof(*offload), GFP_USER); 57 if (!offload) 58 return -ENOMEM; 59 60 offload->prog = prog; 61 62 offload->netdev = dev_get_by_index(current->nsproxy->net_ns, 63 attr->prog_ifindex); 64 err = bpf_dev_offload_check(offload->netdev); 65 if (err) 66 goto err_maybe_put; 67 68 down_write(&bpf_devs_lock); 69 if (offload->netdev->reg_state != NETREG_REGISTERED) { 70 err = -EINVAL; 71 goto err_unlock; 72 } 73 prog->aux->offload = offload; 74 list_add_tail(&offload->offloads, &bpf_prog_offload_devs); 75 dev_put(offload->netdev); 76 up_write(&bpf_devs_lock); 77 78 return 0; 79 err_unlock: 80 up_write(&bpf_devs_lock); 81 err_maybe_put: 82 if (offload->netdev) 83 dev_put(offload->netdev); 84 kfree(offload); 85 return err; 86 } 87 88 static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd, 89 struct netdev_bpf *data) 90 { 91 struct bpf_prog_offload *offload = prog->aux->offload; 92 struct net_device *netdev; 93 94 ASSERT_RTNL(); 95 96 if (!offload) 97 return -ENODEV; 98 netdev = offload->netdev; 99 100 data->command = cmd; 101 102 return netdev->netdev_ops->ndo_bpf(netdev, data); 103 } 104 105 int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env) 106 { 107 struct netdev_bpf data = {}; 108 int err; 109 110 data.verifier.prog = env->prog; 111 112 rtnl_lock(); 113 err = __bpf_offload_ndo(env->prog, BPF_OFFLOAD_VERIFIER_PREP, &data); 114 if (err) 115 goto exit_unlock; 116 117 env->prog->aux->offload->dev_ops = data.verifier.ops; 118 env->prog->aux->offload->dev_state = true; 119 exit_unlock: 120 rtnl_unlock(); 121 return err; 122 } 123 124 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, 125 int insn_idx, int prev_insn_idx) 126 { 127 struct bpf_prog_offload *offload; 128 int ret = -ENODEV; 129 130 down_read(&bpf_devs_lock); 131 offload = env->prog->aux->offload; 132 if (offload) 133 ret = offload->dev_ops->insn_hook(env, insn_idx, prev_insn_idx); 134 up_read(&bpf_devs_lock); 135 136 return ret; 137 } 138 139 static void __bpf_prog_offload_destroy(struct bpf_prog *prog) 140 { 141 struct bpf_prog_offload *offload = prog->aux->offload; 142 struct netdev_bpf data = {}; 143 144 data.offload.prog = prog; 145 146 if (offload->dev_state) 147 WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data)); 148 149 /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */ 150 bpf_prog_free_id(prog, true); 151 152 list_del_init(&offload->offloads); 153 kfree(offload); 154 prog->aux->offload = NULL; 155 } 156 157 void bpf_prog_offload_destroy(struct bpf_prog *prog) 158 { 159 rtnl_lock(); 160 down_write(&bpf_devs_lock); 161 if (prog->aux->offload) 162 __bpf_prog_offload_destroy(prog); 163 up_write(&bpf_devs_lock); 164 rtnl_unlock(); 165 } 166 167 static int bpf_prog_offload_translate(struct bpf_prog *prog) 168 { 169 struct netdev_bpf data = {}; 170 int ret; 171 172 data.offload.prog = prog; 173 174 rtnl_lock(); 175 ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data); 176 rtnl_unlock(); 177 178 return ret; 179 } 180 181 static unsigned int bpf_prog_warn_on_exec(const void *ctx, 182 const struct bpf_insn *insn) 183 { 184 WARN(1, "attempt to execute device eBPF program on the host!"); 185 return 0; 186 } 187 188 int bpf_prog_offload_compile(struct bpf_prog *prog) 189 { 190 prog->bpf_func = bpf_prog_warn_on_exec; 191 192 return bpf_prog_offload_translate(prog); 193 } 194 195 struct ns_get_path_bpf_prog_args { 196 struct bpf_prog *prog; 197 struct bpf_prog_info *info; 198 }; 199 200 static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data) 201 { 202 struct ns_get_path_bpf_prog_args *args = private_data; 203 struct bpf_prog_aux *aux = args->prog->aux; 204 struct ns_common *ns; 205 struct net *net; 206 207 rtnl_lock(); 208 down_read(&bpf_devs_lock); 209 210 if (aux->offload) { 211 args->info->ifindex = aux->offload->netdev->ifindex; 212 net = dev_net(aux->offload->netdev); 213 get_net(net); 214 ns = &net->ns; 215 } else { 216 args->info->ifindex = 0; 217 ns = NULL; 218 } 219 220 up_read(&bpf_devs_lock); 221 rtnl_unlock(); 222 223 return ns; 224 } 225 226 int bpf_prog_offload_info_fill(struct bpf_prog_info *info, 227 struct bpf_prog *prog) 228 { 229 struct ns_get_path_bpf_prog_args args = { 230 .prog = prog, 231 .info = info, 232 }; 233 struct inode *ns_inode; 234 struct path ns_path; 235 void *res; 236 237 res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args); 238 if (IS_ERR(res)) { 239 if (!info->ifindex) 240 return -ENODEV; 241 return PTR_ERR(res); 242 } 243 244 ns_inode = ns_path.dentry->d_inode; 245 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); 246 info->netns_ino = ns_inode->i_ino; 247 path_put(&ns_path); 248 249 return 0; 250 } 251 252 const struct bpf_prog_ops bpf_offload_prog_ops = { 253 }; 254 255 static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap, 256 enum bpf_netdev_command cmd) 257 { 258 struct netdev_bpf data = {}; 259 struct net_device *netdev; 260 261 ASSERT_RTNL(); 262 263 data.command = cmd; 264 data.offmap = offmap; 265 /* Caller must make sure netdev is valid */ 266 netdev = offmap->netdev; 267 268 return netdev->netdev_ops->ndo_bpf(netdev, &data); 269 } 270 271 struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) 272 { 273 struct net *net = current->nsproxy->net_ns; 274 struct bpf_offloaded_map *offmap; 275 int err; 276 277 if (!capable(CAP_SYS_ADMIN)) 278 return ERR_PTR(-EPERM); 279 if (attr->map_type != BPF_MAP_TYPE_HASH) 280 return ERR_PTR(-EINVAL); 281 282 offmap = kzalloc(sizeof(*offmap), GFP_USER); 283 if (!offmap) 284 return ERR_PTR(-ENOMEM); 285 286 bpf_map_init_from_attr(&offmap->map, attr); 287 288 rtnl_lock(); 289 down_write(&bpf_devs_lock); 290 offmap->netdev = __dev_get_by_index(net, attr->map_ifindex); 291 err = bpf_dev_offload_check(offmap->netdev); 292 if (err) 293 goto err_unlock; 294 295 err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC); 296 if (err) 297 goto err_unlock; 298 299 list_add_tail(&offmap->offloads, &bpf_map_offload_devs); 300 up_write(&bpf_devs_lock); 301 rtnl_unlock(); 302 303 return &offmap->map; 304 305 err_unlock: 306 up_write(&bpf_devs_lock); 307 rtnl_unlock(); 308 kfree(offmap); 309 return ERR_PTR(err); 310 } 311 312 static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap) 313 { 314 WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE)); 315 /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */ 316 bpf_map_free_id(&offmap->map, true); 317 list_del_init(&offmap->offloads); 318 offmap->netdev = NULL; 319 } 320 321 void bpf_map_offload_map_free(struct bpf_map *map) 322 { 323 struct bpf_offloaded_map *offmap = map_to_offmap(map); 324 325 rtnl_lock(); 326 down_write(&bpf_devs_lock); 327 if (offmap->netdev) 328 __bpf_map_offload_destroy(offmap); 329 up_write(&bpf_devs_lock); 330 rtnl_unlock(); 331 332 kfree(offmap); 333 } 334 335 int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value) 336 { 337 struct bpf_offloaded_map *offmap = map_to_offmap(map); 338 int ret = -ENODEV; 339 340 down_read(&bpf_devs_lock); 341 if (offmap->netdev) 342 ret = offmap->dev_ops->map_lookup_elem(offmap, key, value); 343 up_read(&bpf_devs_lock); 344 345 return ret; 346 } 347 348 int bpf_map_offload_update_elem(struct bpf_map *map, 349 void *key, void *value, u64 flags) 350 { 351 struct bpf_offloaded_map *offmap = map_to_offmap(map); 352 int ret = -ENODEV; 353 354 if (unlikely(flags > BPF_EXIST)) 355 return -EINVAL; 356 357 down_read(&bpf_devs_lock); 358 if (offmap->netdev) 359 ret = offmap->dev_ops->map_update_elem(offmap, key, value, 360 flags); 361 up_read(&bpf_devs_lock); 362 363 return ret; 364 } 365 366 int bpf_map_offload_delete_elem(struct bpf_map *map, void *key) 367 { 368 struct bpf_offloaded_map *offmap = map_to_offmap(map); 369 int ret = -ENODEV; 370 371 down_read(&bpf_devs_lock); 372 if (offmap->netdev) 373 ret = offmap->dev_ops->map_delete_elem(offmap, key); 374 up_read(&bpf_devs_lock); 375 376 return ret; 377 } 378 379 int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key) 380 { 381 struct bpf_offloaded_map *offmap = map_to_offmap(map); 382 int ret = -ENODEV; 383 384 down_read(&bpf_devs_lock); 385 if (offmap->netdev) 386 ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key); 387 up_read(&bpf_devs_lock); 388 389 return ret; 390 } 391 392 bool bpf_offload_dev_match(struct bpf_prog *prog, struct bpf_map *map) 393 { 394 struct bpf_offloaded_map *offmap; 395 struct bpf_prog_offload *offload; 396 bool ret; 397 398 if (!bpf_prog_is_dev_bound(prog->aux) || !bpf_map_is_dev_bound(map)) 399 return false; 400 401 down_read(&bpf_devs_lock); 402 offload = prog->aux->offload; 403 offmap = map_to_offmap(map); 404 405 ret = offload && offload->netdev == offmap->netdev; 406 up_read(&bpf_devs_lock); 407 408 return ret; 409 } 410 411 static void bpf_offload_orphan_all_progs(struct net_device *netdev) 412 { 413 struct bpf_prog_offload *offload, *tmp; 414 415 list_for_each_entry_safe(offload, tmp, &bpf_prog_offload_devs, offloads) 416 if (offload->netdev == netdev) 417 __bpf_prog_offload_destroy(offload->prog); 418 } 419 420 static void bpf_offload_orphan_all_maps(struct net_device *netdev) 421 { 422 struct bpf_offloaded_map *offmap, *tmp; 423 424 list_for_each_entry_safe(offmap, tmp, &bpf_map_offload_devs, offloads) 425 if (offmap->netdev == netdev) 426 __bpf_map_offload_destroy(offmap); 427 } 428 429 static int bpf_offload_notification(struct notifier_block *notifier, 430 ulong event, void *ptr) 431 { 432 struct net_device *netdev = netdev_notifier_info_to_dev(ptr); 433 434 ASSERT_RTNL(); 435 436 switch (event) { 437 case NETDEV_UNREGISTER: 438 /* ignore namespace changes */ 439 if (netdev->reg_state != NETREG_UNREGISTERING) 440 break; 441 442 down_write(&bpf_devs_lock); 443 bpf_offload_orphan_all_progs(netdev); 444 bpf_offload_orphan_all_maps(netdev); 445 up_write(&bpf_devs_lock); 446 break; 447 default: 448 break; 449 } 450 return NOTIFY_OK; 451 } 452 453 static struct notifier_block bpf_offload_notifier = { 454 .notifier_call = bpf_offload_notification, 455 }; 456 457 static int __init bpf_offload_init(void) 458 { 459 register_netdevice_notifier(&bpf_offload_notifier); 460 return 0; 461 } 462 463 subsys_initcall(bpf_offload_init); 464