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 10char _license[] SEC("license") = "GPL"; 11 12struct { 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 22struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; 23void bpf_key_put(struct bpf_key *key) __ksym; 24void bpf_rcu_read_lock(void) __ksym; 25void bpf_rcu_read_unlock(void) __ksym; 26struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; 27void bpf_task_release(struct task_struct *p) __ksym; 28 29SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 30int 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; 45unlock: 46 bpf_rcu_read_unlock(); 47 return 0; 48} 49 50SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 51int 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; 74out: 75 bpf_rcu_read_unlock(); 76 return 0; 77} 78 79SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 80int 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 91SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 92int 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); 105out: 106 bpf_rcu_read_unlock(); 107 return 0; 108} 109 110SEC("?fentry/" SYS_PREFIX "sys_getpgid") 111int 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); 121out: 122 bpf_rcu_read_unlock(); 123 return 0; 124} 125 126SEC("?fentry/" SYS_PREFIX "sys_getpgid") 127int 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); 140out: 141 bpf_rcu_read_unlock(); 142 return 0; 143} 144 145SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 146int 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); 168out: 169 bpf_rcu_read_unlock(); 170 return 0; 171} 172 173SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 174int 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 187SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 188int 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 199SEC("?fentry/" SYS_PREFIX "sys_getpgid") 200int 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(); 213out: 214 return 0; 215} 216 217SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 218int 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); 239out: 240 bpf_rcu_read_unlock(); 241 return 0; 242} 243 244SEC("?lsm.s/bpf") 245int BPF_PROG(inproper_sleepable_kfunc, int cmd, union bpf_attr *attr, unsigned int size) 246{ 247 struct bpf_key *bkey; 248 249 /* sleepable kfunc in rcu read lock region */ 250 bpf_rcu_read_lock(); 251 bkey = bpf_lookup_user_key(key_serial, flags); 252 bpf_rcu_read_unlock(); 253 if (!bkey) 254 return -1; 255 bpf_key_put(bkey); 256 257 return 0; 258} 259 260SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 261int nested_rcu_region(void *ctx) 262{ 263 struct task_struct *task, *real_parent; 264 265 /* nested rcu read lock regions */ 266 task = bpf_get_current_task_btf(); 267 bpf_rcu_read_lock(); 268 bpf_rcu_read_lock(); 269 real_parent = task->real_parent; 270 if (!real_parent) 271 goto out; 272 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 273out: 274 bpf_rcu_read_unlock(); 275 bpf_rcu_read_unlock(); 276 return 0; 277} 278 279SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 280int task_trusted_non_rcuptr(void *ctx) 281{ 282 struct task_struct *task, *group_leader; 283 284 task = bpf_get_current_task_btf(); 285 bpf_rcu_read_lock(); 286 /* the pointer group_leader is explicitly marked as trusted */ 287 group_leader = task->real_parent->group_leader; 288 (void)bpf_task_storage_get(&map_a, group_leader, 0, 0); 289 bpf_rcu_read_unlock(); 290 return 0; 291} 292 293SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 294int task_untrusted_rcuptr(void *ctx) 295{ 296 struct task_struct *task, *real_parent; 297 298 task = bpf_get_current_task_btf(); 299 bpf_rcu_read_lock(); 300 real_parent = task->real_parent; 301 bpf_rcu_read_unlock(); 302 /* helper use of rcu ptr outside the rcu read lock region */ 303 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 304 return 0; 305} 306 307SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") 308int cross_rcu_region(void *ctx) 309{ 310 struct task_struct *task, *real_parent; 311 312 /* rcu ptr define/use in different regions */ 313 task = bpf_get_current_task_btf(); 314 bpf_rcu_read_lock(); 315 real_parent = task->real_parent; 316 bpf_rcu_read_unlock(); 317 bpf_rcu_read_lock(); 318 (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); 319 bpf_rcu_read_unlock(); 320 return 0; 321} 322 323__noinline 324static int static_subprog(void *ctx) 325{ 326 volatile int ret = 0; 327 328 if (bpf_get_prandom_u32()) 329 return ret + 42; 330 return ret + bpf_get_prandom_u32(); 331} 332 333__noinline 334int global_subprog(u64 a) 335{ 336 volatile int ret = a; 337 338 return ret + static_subprog(NULL); 339} 340 341__noinline 342static int static_subprog_lock(void *ctx) 343{ 344 volatile int ret = 0; 345 346 bpf_rcu_read_lock(); 347 if (bpf_get_prandom_u32()) 348 return ret + 42; 349 return ret + bpf_get_prandom_u32(); 350} 351 352__noinline 353int global_subprog_lock(u64 a) 354{ 355 volatile int ret = a; 356 357 return ret + static_subprog_lock(NULL); 358} 359 360__noinline 361static int static_subprog_unlock(void *ctx) 362{ 363 volatile int ret = 0; 364 365 bpf_rcu_read_unlock(); 366 if (bpf_get_prandom_u32()) 367 return ret + 42; 368 return ret + bpf_get_prandom_u32(); 369} 370 371__noinline 372int global_subprog_unlock(u64 a) 373{ 374 volatile int ret = a; 375 376 return ret + static_subprog_unlock(NULL); 377} 378 379SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 380int rcu_read_lock_subprog(void *ctx) 381{ 382 volatile int ret = 0; 383 384 bpf_rcu_read_lock(); 385 if (bpf_get_prandom_u32()) 386 ret += static_subprog(ctx); 387 bpf_rcu_read_unlock(); 388 return 0; 389} 390 391SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 392int rcu_read_lock_global_subprog(void *ctx) 393{ 394 volatile int ret = 0; 395 396 bpf_rcu_read_lock(); 397 if (bpf_get_prandom_u32()) 398 ret += global_subprog(ret); 399 bpf_rcu_read_unlock(); 400 return 0; 401} 402 403SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 404int rcu_read_lock_subprog_lock(void *ctx) 405{ 406 volatile int ret = 0; 407 408 ret += static_subprog_lock(ctx); 409 bpf_rcu_read_unlock(); 410 return 0; 411} 412 413SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 414int rcu_read_lock_global_subprog_lock(void *ctx) 415{ 416 volatile int ret = 0; 417 418 ret += global_subprog_lock(ret); 419 bpf_rcu_read_unlock(); 420 return 0; 421} 422 423SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 424int rcu_read_lock_subprog_unlock(void *ctx) 425{ 426 volatile int ret = 0; 427 428 bpf_rcu_read_lock(); 429 ret += static_subprog_unlock(ctx); 430 return 0; 431} 432 433SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 434int rcu_read_lock_global_subprog_unlock(void *ctx) 435{ 436 volatile int ret = 0; 437 438 bpf_rcu_read_lock(); 439 ret += global_subprog_unlock(ret); 440 return 0; 441} 442