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, target_pid; 20 __s32 key_serial; 21 __u64 flags, task_storage_val, cgroup_id; 22 23 struct bpf_key *bpf_lookup_user_key(__s32 serial, __u64 flags) __ksym; 24 void bpf_key_put(struct bpf_key *key) __ksym; 25 void bpf_rcu_read_lock(void) __ksym; 26 void bpf_rcu_read_unlock(void) __ksym; 27 struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; 28 void bpf_task_release(struct task_struct *p) __ksym; 29 30 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 31 int get_cgroup_id(void *ctx) 32 { 33 struct task_struct *task; 34 struct css_set *cgroups; 35 36 task = bpf_get_current_task_btf(); 37 if (task->pid != target_pid) 38 return 0; 39 40 /* simulate bpf_get_current_cgroup_id() helper */ 41 bpf_rcu_read_lock(); 42 cgroups = task->cgroups; 43 if (!cgroups) 44 goto unlock; 45 cgroup_id = cgroups->dfl_cgrp->kn->id; 46 unlock: 47 bpf_rcu_read_unlock(); 48 return 0; 49 } 50 51 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 52 int task_succ(void *ctx) 53 { 54 struct task_struct *task, *real_parent; 55 long init_val = 2; 56 long *ptr; 57 58 task = bpf_get_current_task_btf(); 59 if (task->pid != target_pid) 60 return 0; 61 62 bpf_rcu_read_lock(); 63 /* region including helper using rcu ptr real_parent */ 64 real_parent = task->real_parent; 65 if (!real_parent) 66 goto out; 67 ptr = bpf_task_storage_get(&map_a, real_parent, &init_val, 68 BPF_LOCAL_STORAGE_GET_F_CREATE); 69 if (!ptr) 70 goto out; 71 ptr = bpf_task_storage_get(&map_a, real_parent, 0, 0); 72 if (!ptr) 73 goto out; 74 task_storage_val = *ptr; 75 out: 76 bpf_rcu_read_unlock(); 77 return 0; 78 } 79 80 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 81 int no_lock(void *ctx) 82 { 83 struct task_struct *task, *real_parent; 84 85 /* old style ptr_to_btf_id is not allowed in sleepable */ 86 task = bpf_get_current_task_btf(); 87 real_parent = task->real_parent; 88 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 89 return 0; 90 } 91 92 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 93 int two_regions(void *ctx) 94 { 95 struct task_struct *task, *real_parent; 96 97 /* two regions */ 98 task = bpf_get_current_task_btf(); 99 bpf_rcu_read_lock(); 100 bpf_rcu_read_unlock(); 101 bpf_rcu_read_lock(); 102 real_parent = task->real_parent; 103 if (!real_parent) 104 goto out; 105 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 106 out: 107 bpf_rcu_read_unlock(); 108 return 0; 109 } 110 111 SEC("?fentry/" SYS_PREFIX "sys_getpgid") 112 int non_sleepable_1(void *ctx) 113 { 114 struct task_struct *task, *real_parent; 115 116 task = bpf_get_current_task_btf(); 117 bpf_rcu_read_lock(); 118 real_parent = task->real_parent; 119 if (!real_parent) 120 goto out; 121 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 122 out: 123 bpf_rcu_read_unlock(); 124 return 0; 125 } 126 127 SEC("?fentry/" SYS_PREFIX "sys_getpgid") 128 int non_sleepable_2(void *ctx) 129 { 130 struct task_struct *task, *real_parent; 131 132 bpf_rcu_read_lock(); 133 task = bpf_get_current_task_btf(); 134 bpf_rcu_read_unlock(); 135 136 bpf_rcu_read_lock(); 137 real_parent = task->real_parent; 138 if (!real_parent) 139 goto out; 140 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 141 out: 142 bpf_rcu_read_unlock(); 143 return 0; 144 } 145 146 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 147 int task_acquire(void *ctx) 148 { 149 struct task_struct *task, *real_parent, *gparent; 150 151 task = bpf_get_current_task_btf(); 152 bpf_rcu_read_lock(); 153 real_parent = task->real_parent; 154 if (!real_parent) 155 goto out; 156 157 /* rcu_ptr->rcu_field */ 158 gparent = real_parent->real_parent; 159 if (!gparent) 160 goto out; 161 162 /* acquire a reference which can be used outside rcu read lock region */ 163 gparent = bpf_task_acquire(gparent); 164 if (!gparent) 165 goto out; 166 167 (void)bpf_task_storage_get(&map_a, gparent, 0, 0); 168 bpf_task_release(gparent); 169 out: 170 bpf_rcu_read_unlock(); 171 return 0; 172 } 173 174 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 175 int miss_lock(void *ctx) 176 { 177 struct task_struct *task; 178 179 /* missing bpf_rcu_read_lock() */ 180 task = bpf_get_current_task_btf(); 181 bpf_rcu_read_lock(); 182 (void)bpf_task_storage_get(&map_a, task, 0, 0); 183 bpf_rcu_read_unlock(); 184 bpf_rcu_read_unlock(); 185 return 0; 186 } 187 188 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 189 int miss_unlock(void *ctx) 190 { 191 struct task_struct *task; 192 193 /* missing bpf_rcu_read_unlock() */ 194 task = bpf_get_current_task_btf(); 195 bpf_rcu_read_lock(); 196 (void)bpf_task_storage_get(&map_a, task, 0, 0); 197 return 0; 198 } 199 200 SEC("?fentry/" SYS_PREFIX "sys_getpgid") 201 int non_sleepable_rcu_mismatch(void *ctx) 202 { 203 struct task_struct *task, *real_parent; 204 205 task = bpf_get_current_task_btf(); 206 /* non-sleepable: missing bpf_rcu_read_unlock() in one path */ 207 bpf_rcu_read_lock(); 208 real_parent = task->real_parent; 209 if (!real_parent) 210 goto out; 211 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 212 if (real_parent) 213 bpf_rcu_read_unlock(); 214 out: 215 return 0; 216 } 217 218 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 219 int inproper_sleepable_helper(void *ctx) 220 { 221 struct task_struct *task, *real_parent; 222 struct pt_regs *regs; 223 __u32 value = 0; 224 void *ptr; 225 226 task = bpf_get_current_task_btf(); 227 /* sleepable helper in rcu read lock region */ 228 bpf_rcu_read_lock(); 229 real_parent = task->real_parent; 230 if (!real_parent) 231 goto out; 232 regs = (struct pt_regs *)bpf_task_pt_regs(real_parent); 233 if (!regs) 234 goto out; 235 236 ptr = (void *)PT_REGS_IP(regs); 237 (void)bpf_copy_from_user_task(&value, sizeof(uint32_t), ptr, task, 0); 238 user_data = value; 239 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 240 out: 241 bpf_rcu_read_unlock(); 242 return 0; 243 } 244 245 SEC("?lsm.s/bpf") 246 int BPF_PROG(inproper_sleepable_kfunc, int cmd, union bpf_attr *attr, unsigned int size, 247 bool kernel) 248 { 249 struct bpf_key *bkey; 250 251 /* sleepable kfunc in rcu read lock region */ 252 bpf_rcu_read_lock(); 253 bkey = bpf_lookup_user_key(key_serial, flags); 254 bpf_rcu_read_unlock(); 255 if (!bkey) 256 return -1; 257 bpf_key_put(bkey); 258 259 return 0; 260 } 261 262 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 263 int nested_rcu_region(void *ctx) 264 { 265 struct task_struct *task, *real_parent; 266 267 /* nested rcu read lock regions */ 268 task = bpf_get_current_task_btf(); 269 bpf_rcu_read_lock(); 270 bpf_rcu_read_lock(); 271 real_parent = task->real_parent; 272 if (!real_parent) 273 goto out; 274 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 275 out: 276 bpf_rcu_read_unlock(); 277 bpf_rcu_read_unlock(); 278 return 0; 279 } 280 281 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 282 int task_trusted_non_rcuptr(void *ctx) 283 { 284 struct task_struct *task, *group_leader; 285 286 task = bpf_get_current_task_btf(); 287 bpf_rcu_read_lock(); 288 /* the pointer group_leader is explicitly marked as trusted */ 289 group_leader = task->real_parent->group_leader; 290 (void)bpf_task_storage_get(&map_a, group_leader, 0, 0); 291 bpf_rcu_read_unlock(); 292 return 0; 293 } 294 295 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 296 int task_untrusted_rcuptr(void *ctx) 297 { 298 struct task_struct *task, *real_parent; 299 300 task = bpf_get_current_task_btf(); 301 bpf_rcu_read_lock(); 302 real_parent = task->real_parent; 303 bpf_rcu_read_unlock(); 304 /* helper use of rcu ptr outside the rcu read lock region */ 305 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 306 return 0; 307 } 308 309 SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 310 int cross_rcu_region(void *ctx) 311 { 312 struct task_struct *task, *real_parent; 313 314 /* rcu ptr define/use in different regions */ 315 task = bpf_get_current_task_btf(); 316 bpf_rcu_read_lock(); 317 real_parent = task->real_parent; 318 bpf_rcu_read_unlock(); 319 bpf_rcu_read_lock(); 320 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 321 bpf_rcu_read_unlock(); 322 return 0; 323 } 324 325 __noinline 326 static int static_subprog(void *ctx) 327 { 328 volatile int ret = 0; 329 330 if (bpf_get_prandom_u32()) 331 return ret + 42; 332 return ret + bpf_get_prandom_u32(); 333 } 334 335 __noinline 336 int global_subprog(u64 a) 337 { 338 volatile int ret = a; 339 340 return ret + static_subprog(NULL); 341 } 342 343 __noinline 344 static int static_subprog_lock(void *ctx) 345 { 346 volatile int ret = 0; 347 348 bpf_rcu_read_lock(); 349 if (bpf_get_prandom_u32()) 350 return ret + 42; 351 return ret + bpf_get_prandom_u32(); 352 } 353 354 __noinline 355 int global_subprog_lock(u64 a) 356 { 357 volatile int ret = a; 358 359 return ret + static_subprog_lock(NULL); 360 } 361 362 __noinline 363 static int static_subprog_unlock(void *ctx) 364 { 365 volatile int ret = 0; 366 367 bpf_rcu_read_unlock(); 368 if (bpf_get_prandom_u32()) 369 return ret + 42; 370 return ret + bpf_get_prandom_u32(); 371 } 372 373 __noinline 374 int global_subprog_unlock(u64 a) 375 { 376 volatile int ret = a; 377 378 return ret + static_subprog_unlock(NULL); 379 } 380 381 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 382 int rcu_read_lock_subprog(void *ctx) 383 { 384 volatile int ret = 0; 385 386 bpf_rcu_read_lock(); 387 if (bpf_get_prandom_u32()) 388 ret += static_subprog(ctx); 389 bpf_rcu_read_unlock(); 390 return 0; 391 } 392 393 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 394 int rcu_read_lock_global_subprog(void *ctx) 395 { 396 volatile int ret = 0; 397 398 bpf_rcu_read_lock(); 399 if (bpf_get_prandom_u32()) 400 ret += global_subprog(ret); 401 bpf_rcu_read_unlock(); 402 return 0; 403 } 404 405 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 406 int rcu_read_lock_subprog_lock(void *ctx) 407 { 408 volatile int ret = 0; 409 410 ret += static_subprog_lock(ctx); 411 bpf_rcu_read_unlock(); 412 return 0; 413 } 414 415 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 416 int rcu_read_lock_global_subprog_lock(void *ctx) 417 { 418 volatile int ret = 0; 419 420 ret += global_subprog_lock(ret); 421 bpf_rcu_read_unlock(); 422 return 0; 423 } 424 425 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 426 int rcu_read_lock_subprog_unlock(void *ctx) 427 { 428 volatile int ret = 0; 429 430 bpf_rcu_read_lock(); 431 ret += static_subprog_unlock(ctx); 432 return 0; 433 } 434 435 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 436 int rcu_read_lock_global_subprog_unlock(void *ctx) 437 { 438 volatile int ret = 0; 439 440 bpf_rcu_read_lock(); 441 ret += global_subprog_unlock(ret); 442 return 0; 443 } 444 445 int __noinline 446 global_sleepable_helper_subprog(int i) 447 { 448 if (i) 449 bpf_copy_from_user(&i, sizeof(i), NULL); 450 return i; 451 } 452 453 int __noinline 454 global_sleepable_kfunc_subprog(int i) 455 { 456 if (i) 457 bpf_copy_from_user_str(&i, sizeof(i), NULL, 0); 458 global_subprog(i); 459 return i; 460 } 461 462 int __noinline 463 global_subprog_calling_sleepable_global(int i) 464 { 465 if (!i) 466 global_sleepable_kfunc_subprog(i); 467 return i; 468 } 469 470 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 471 int rcu_read_lock_sleepable_helper_global_subprog(void *ctx) 472 { 473 volatile int ret = 0; 474 475 bpf_rcu_read_lock(); 476 ret += global_sleepable_helper_subprog(ret); 477 bpf_rcu_read_unlock(); 478 return 0; 479 } 480 481 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 482 int rcu_read_lock_sleepable_kfunc_global_subprog(void *ctx) 483 { 484 volatile int ret = 0; 485 486 bpf_rcu_read_lock(); 487 ret += global_sleepable_kfunc_subprog(ret); 488 bpf_rcu_read_unlock(); 489 return 0; 490 } 491 492 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 493 int rcu_read_lock_sleepable_global_subprog_indirect(void *ctx) 494 { 495 volatile int ret = 0; 496 497 bpf_rcu_read_lock(); 498 ret += global_subprog_calling_sleepable_global(ret); 499 bpf_rcu_read_unlock(); 500 return 0; 501 } 502