1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ 3 4 #include "vmlinux.h" 5 #include <bpf/bpf_helpers.h> 6 #include <bpf/bpf_tracing.h> 7 #include "bpf_tracing_net.h" 8 #include "bpf_misc.h" 9 10 char _license[] SEC("license") = "GPL"; 11 12 struct { 13 __uint(type, BPF_MAP_TYPE_TASK_STORAGE); 14 __uint(map_flags, BPF_F_NO_PREALLOC); 15 __type(key, int); 16 __type(value, long); 17 } map_a SEC(".maps"); 18 19 __u32 user_data, key_serial, target_pid; 20 __u64 flags, task_storage_val, cgroup_id; 21 22 struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; 23 void bpf_key_put(struct bpf_key *key) __ksym; 24 void bpf_rcu_read_lock(void) __ksym; 25 void bpf_rcu_read_unlock(void) __ksym; 26 struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; 27 void bpf_task_release(struct task_struct *p) __ksym; 28 29 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 30 int get_cgroup_id(void *ctx) 31 { 32 struct task_struct *task; 33 struct css_set *cgroups; 34 35 task = bpf_get_current_task_btf(); 36 if (task->pid != target_pid) 37 return 0; 38 39 /* simulate bpf_get_current_cgroup_id() helper */ 40 bpf_rcu_read_lock(); 41 cgroups = task->cgroups; 42 if (!cgroups) 43 goto unlock; 44 cgroup_id = cgroups->dfl_cgrp->kn->id; 45 unlock: 46 bpf_rcu_read_unlock(); 47 return 0; 48 } 49 50 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 51 int task_succ(void *ctx) 52 { 53 struct task_struct *task, *real_parent; 54 long init_val = 2; 55 long *ptr; 56 57 task = bpf_get_current_task_btf(); 58 if (task->pid != target_pid) 59 return 0; 60 61 bpf_rcu_read_lock(); 62 /* region including helper using rcu ptr real_parent */ 63 real_parent = task->real_parent; 64 if (!real_parent) 65 goto out; 66 ptr = bpf_task_storage_get(&map_a, real_parent, &init_val, 67 BPF_LOCAL_STORAGE_GET_F_CREATE); 68 if (!ptr) 69 goto out; 70 ptr = bpf_task_storage_get(&map_a, real_parent, 0, 0); 71 if (!ptr) 72 goto out; 73 task_storage_val = *ptr; 74 out: 75 bpf_rcu_read_unlock(); 76 return 0; 77 } 78 79 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 80 int no_lock(void *ctx) 81 { 82 struct task_struct *task, *real_parent; 83 84 /* old style ptr_to_btf_id is not allowed in sleepable */ 85 task = bpf_get_current_task_btf(); 86 real_parent = task->real_parent; 87 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 88 return 0; 89 } 90 91 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 92 int two_regions(void *ctx) 93 { 94 struct task_struct *task, *real_parent; 95 96 /* two regions */ 97 task = bpf_get_current_task_btf(); 98 bpf_rcu_read_lock(); 99 bpf_rcu_read_unlock(); 100 bpf_rcu_read_lock(); 101 real_parent = task->real_parent; 102 if (!real_parent) 103 goto out; 104 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 105 out: 106 bpf_rcu_read_unlock(); 107 return 0; 108 } 109 110 SEC("?fentry/" SYS_PREFIX "sys_getpgid") 111 int non_sleepable_1(void *ctx) 112 { 113 struct task_struct *task, *real_parent; 114 115 task = bpf_get_current_task_btf(); 116 bpf_rcu_read_lock(); 117 real_parent = task->real_parent; 118 if (!real_parent) 119 goto out; 120 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 121 out: 122 bpf_rcu_read_unlock(); 123 return 0; 124 } 125 126 SEC("?fentry/" SYS_PREFIX "sys_getpgid") 127 int non_sleepable_2(void *ctx) 128 { 129 struct task_struct *task, *real_parent; 130 131 bpf_rcu_read_lock(); 132 task = bpf_get_current_task_btf(); 133 bpf_rcu_read_unlock(); 134 135 bpf_rcu_read_lock(); 136 real_parent = task->real_parent; 137 if (!real_parent) 138 goto out; 139 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 140 out: 141 bpf_rcu_read_unlock(); 142 return 0; 143 } 144 145 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 146 int task_acquire(void *ctx) 147 { 148 struct task_struct *task, *real_parent, *gparent; 149 150 task = bpf_get_current_task_btf(); 151 bpf_rcu_read_lock(); 152 real_parent = task->real_parent; 153 if (!real_parent) 154 goto out; 155 156 /* rcu_ptr->rcu_field */ 157 gparent = real_parent->real_parent; 158 if (!gparent) 159 goto out; 160 161 /* acquire a reference which can be used outside rcu read lock region */ 162 gparent = bpf_task_acquire(gparent); 163 if (!gparent) 164 goto out; 165 166 (void)bpf_task_storage_get(&map_a, gparent, 0, 0); 167 bpf_task_release(gparent); 168 out: 169 bpf_rcu_read_unlock(); 170 return 0; 171 } 172 173 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 174 int miss_lock(void *ctx) 175 { 176 struct task_struct *task; 177 178 /* missing bpf_rcu_read_lock() */ 179 task = bpf_get_current_task_btf(); 180 bpf_rcu_read_lock(); 181 (void)bpf_task_storage_get(&map_a, task, 0, 0); 182 bpf_rcu_read_unlock(); 183 bpf_rcu_read_unlock(); 184 return 0; 185 } 186 187 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 188 int miss_unlock(void *ctx) 189 { 190 struct task_struct *task; 191 192 /* missing bpf_rcu_read_unlock() */ 193 task = bpf_get_current_task_btf(); 194 bpf_rcu_read_lock(); 195 (void)bpf_task_storage_get(&map_a, task, 0, 0); 196 return 0; 197 } 198 199 SEC("?fentry/" SYS_PREFIX "sys_getpgid") 200 int non_sleepable_rcu_mismatch(void *ctx) 201 { 202 struct task_struct *task, *real_parent; 203 204 task = bpf_get_current_task_btf(); 205 /* non-sleepable: missing bpf_rcu_read_unlock() in one path */ 206 bpf_rcu_read_lock(); 207 real_parent = task->real_parent; 208 if (!real_parent) 209 goto out; 210 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 211 if (real_parent) 212 bpf_rcu_read_unlock(); 213 out: 214 return 0; 215 } 216 217 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 218 int inproper_sleepable_helper(void *ctx) 219 { 220 struct task_struct *task, *real_parent; 221 struct pt_regs *regs; 222 __u32 value = 0; 223 void *ptr; 224 225 task = bpf_get_current_task_btf(); 226 /* sleepable helper in rcu read lock region */ 227 bpf_rcu_read_lock(); 228 real_parent = task->real_parent; 229 if (!real_parent) 230 goto out; 231 regs = (struct pt_regs *)bpf_task_pt_regs(real_parent); 232 if (!regs) 233 goto out; 234 235 ptr = (void *)PT_REGS_IP(regs); 236 (void)bpf_copy_from_user_task(&value, sizeof(uint32_t), ptr, task, 0); 237 user_data = value; 238 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 239 out: 240 bpf_rcu_read_unlock(); 241 return 0; 242 } 243 244 SEC("?lsm.s/bpf") 245 int BPF_PROG(inproper_sleepable_kfunc, int cmd, union bpf_attr *attr, unsigned int size, 246 bool kernel) 247 { 248 struct bpf_key *bkey; 249 250 /* sleepable kfunc in rcu read lock region */ 251 bpf_rcu_read_lock(); 252 bkey = bpf_lookup_user_key(key_serial, flags); 253 bpf_rcu_read_unlock(); 254 if (!bkey) 255 return -1; 256 bpf_key_put(bkey); 257 258 return 0; 259 } 260 261 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 262 int nested_rcu_region(void *ctx) 263 { 264 struct task_struct *task, *real_parent; 265 266 /* nested rcu read lock regions */ 267 task = bpf_get_current_task_btf(); 268 bpf_rcu_read_lock(); 269 bpf_rcu_read_lock(); 270 real_parent = task->real_parent; 271 if (!real_parent) 272 goto out; 273 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 274 out: 275 bpf_rcu_read_unlock(); 276 bpf_rcu_read_unlock(); 277 return 0; 278 } 279 280 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 281 int task_trusted_non_rcuptr(void *ctx) 282 { 283 struct task_struct *task, *group_leader; 284 285 task = bpf_get_current_task_btf(); 286 bpf_rcu_read_lock(); 287 /* the pointer group_leader is explicitly marked as trusted */ 288 group_leader = task->real_parent->group_leader; 289 (void)bpf_task_storage_get(&map_a, group_leader, 0, 0); 290 bpf_rcu_read_unlock(); 291 return 0; 292 } 293 294 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 295 int task_untrusted_rcuptr(void *ctx) 296 { 297 struct task_struct *task, *real_parent; 298 299 task = bpf_get_current_task_btf(); 300 bpf_rcu_read_lock(); 301 real_parent = task->real_parent; 302 bpf_rcu_read_unlock(); 303 /* helper use of rcu ptr outside the rcu read lock region */ 304 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 305 return 0; 306 } 307 308 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 309 int cross_rcu_region(void *ctx) 310 { 311 struct task_struct *task, *real_parent; 312 313 /* rcu ptr define/use in different regions */ 314 task = bpf_get_current_task_btf(); 315 bpf_rcu_read_lock(); 316 real_parent = task->real_parent; 317 bpf_rcu_read_unlock(); 318 bpf_rcu_read_lock(); 319 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 320 bpf_rcu_read_unlock(); 321 return 0; 322 } 323 324 __noinline 325 static int static_subprog(void *ctx) 326 { 327 volatile int ret = 0; 328 329 if (bpf_get_prandom_u32()) 330 return ret + 42; 331 return ret + bpf_get_prandom_u32(); 332 } 333 334 __noinline 335 int global_subprog(u64 a) 336 { 337 volatile int ret = a; 338 339 return ret + static_subprog(NULL); 340 } 341 342 __noinline 343 static int static_subprog_lock(void *ctx) 344 { 345 volatile int ret = 0; 346 347 bpf_rcu_read_lock(); 348 if (bpf_get_prandom_u32()) 349 return ret + 42; 350 return ret + bpf_get_prandom_u32(); 351 } 352 353 __noinline 354 int global_subprog_lock(u64 a) 355 { 356 volatile int ret = a; 357 358 return ret + static_subprog_lock(NULL); 359 } 360 361 __noinline 362 static int static_subprog_unlock(void *ctx) 363 { 364 volatile int ret = 0; 365 366 bpf_rcu_read_unlock(); 367 if (bpf_get_prandom_u32()) 368 return ret + 42; 369 return ret + bpf_get_prandom_u32(); 370 } 371 372 __noinline 373 int global_subprog_unlock(u64 a) 374 { 375 volatile int ret = a; 376 377 return ret + static_subprog_unlock(NULL); 378 } 379 380 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 381 int rcu_read_lock_subprog(void *ctx) 382 { 383 volatile int ret = 0; 384 385 bpf_rcu_read_lock(); 386 if (bpf_get_prandom_u32()) 387 ret += static_subprog(ctx); 388 bpf_rcu_read_unlock(); 389 return 0; 390 } 391 392 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 393 int rcu_read_lock_global_subprog(void *ctx) 394 { 395 volatile int ret = 0; 396 397 bpf_rcu_read_lock(); 398 if (bpf_get_prandom_u32()) 399 ret += global_subprog(ret); 400 bpf_rcu_read_unlock(); 401 return 0; 402 } 403 404 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 405 int rcu_read_lock_subprog_lock(void *ctx) 406 { 407 volatile int ret = 0; 408 409 ret += static_subprog_lock(ctx); 410 bpf_rcu_read_unlock(); 411 return 0; 412 } 413 414 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 415 int rcu_read_lock_global_subprog_lock(void *ctx) 416 { 417 volatile int ret = 0; 418 419 ret += global_subprog_lock(ret); 420 bpf_rcu_read_unlock(); 421 return 0; 422 } 423 424 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 425 int rcu_read_lock_subprog_unlock(void *ctx) 426 { 427 volatile int ret = 0; 428 429 bpf_rcu_read_lock(); 430 ret += static_subprog_unlock(ctx); 431 return 0; 432 } 433 434 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 435 int rcu_read_lock_global_subprog_unlock(void *ctx) 436 { 437 volatile int ret = 0; 438 439 bpf_rcu_read_lock(); 440 ret += global_subprog_unlock(ret); 441 return 0; 442 } 443 444 int __noinline 445 global_sleepable_helper_subprog(int i) 446 { 447 if (i) 448 bpf_copy_from_user(&i, sizeof(i), NULL); 449 return i; 450 } 451 452 int __noinline 453 global_sleepable_kfunc_subprog(int i) 454 { 455 if (i) 456 bpf_copy_from_user_str(&i, sizeof(i), NULL, 0); 457 global_subprog(i); 458 return i; 459 } 460 461 int __noinline 462 global_subprog_calling_sleepable_global(int i) 463 { 464 if (!i) 465 global_sleepable_kfunc_subprog(i); 466 return i; 467 } 468 469 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 470 int rcu_read_lock_sleepable_helper_global_subprog(void *ctx) 471 { 472 volatile int ret = 0; 473 474 bpf_rcu_read_lock(); 475 ret += global_sleepable_helper_subprog(ret); 476 bpf_rcu_read_unlock(); 477 return 0; 478 } 479 480 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 481 int rcu_read_lock_sleepable_kfunc_global_subprog(void *ctx) 482 { 483 volatile int ret = 0; 484 485 bpf_rcu_read_lock(); 486 ret += global_sleepable_kfunc_subprog(ret); 487 bpf_rcu_read_unlock(); 488 return 0; 489 } 490 491 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 492 int rcu_read_lock_sleepable_global_subprog_indirect(void *ctx) 493 { 494 volatile int ret = 0; 495 496 bpf_rcu_read_lock(); 497 ret += global_subprog_calling_sleepable_global(ret); 498 bpf_rcu_read_unlock(); 499 return 0; 500 } 501