1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com 3 * Copyright (c) 2016 Facebook 4 */ 5 #include <linux/kernel.h> 6 #include <linux/types.h> 7 #include <linux/slab.h> 8 #include <linux/bpf.h> 9 #include <linux/bpf_perf_event.h> 10 #include <linux/filter.h> 11 #include <linux/uaccess.h> 12 #include <linux/ctype.h> 13 #include <linux/kprobes.h> 14 #include <linux/syscalls.h> 15 #include <linux/error-injection.h> 16 17 #include <asm/tlb.h> 18 19 #include "trace_probe.h" 20 #include "trace.h" 21 22 #define bpf_event_rcu_dereference(p) \ 23 rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) 24 25 #ifdef CONFIG_MODULES 26 struct bpf_trace_module { 27 struct module *module; 28 struct list_head list; 29 }; 30 31 static LIST_HEAD(bpf_trace_modules); 32 static DEFINE_MUTEX(bpf_module_mutex); 33 34 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 35 { 36 struct bpf_raw_event_map *btp, *ret = NULL; 37 struct bpf_trace_module *btm; 38 unsigned int i; 39 40 mutex_lock(&bpf_module_mutex); 41 list_for_each_entry(btm, &bpf_trace_modules, list) { 42 for (i = 0; i < btm->module->num_bpf_raw_events; ++i) { 43 btp = &btm->module->bpf_raw_events[i]; 44 if (!strcmp(btp->tp->name, name)) { 45 if (try_module_get(btm->module)) 46 ret = btp; 47 goto out; 48 } 49 } 50 } 51 out: 52 mutex_unlock(&bpf_module_mutex); 53 return ret; 54 } 55 #else 56 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 57 { 58 return NULL; 59 } 60 #endif /* CONFIG_MODULES */ 61 62 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 63 u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 64 65 /** 66 * trace_call_bpf - invoke BPF program 67 * @call: tracepoint event 68 * @ctx: opaque context pointer 69 * 70 * kprobe handlers execute BPF programs via this helper. 71 * Can be used from static tracepoints in the future. 72 * 73 * Return: BPF programs always return an integer which is interpreted by 74 * kprobe handler as: 75 * 0 - return from kprobe (event is filtered out) 76 * 1 - store kprobe event into ring buffer 77 * Other values are reserved and currently alias to 1 78 */ 79 unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) 80 { 81 unsigned int ret; 82 83 if (in_nmi()) /* not supported yet */ 84 return 1; 85 86 preempt_disable(); 87 88 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { 89 /* 90 * since some bpf program is already running on this cpu, 91 * don't call into another bpf program (same or different) 92 * and don't send kprobe event into ring-buffer, 93 * so return zero here 94 */ 95 ret = 0; 96 goto out; 97 } 98 99 /* 100 * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock 101 * to all call sites, we did a bpf_prog_array_valid() there to check 102 * whether call->prog_array is empty or not, which is 103 * a heurisitc to speed up execution. 104 * 105 * If bpf_prog_array_valid() fetched prog_array was 106 * non-NULL, we go into trace_call_bpf() and do the actual 107 * proper rcu_dereference() under RCU lock. 108 * If it turns out that prog_array is NULL then, we bail out. 109 * For the opposite, if the bpf_prog_array_valid() fetched pointer 110 * was NULL, you'll skip the prog_array with the risk of missing 111 * out of events when it was updated in between this and the 112 * rcu_dereference() which is accepted risk. 113 */ 114 ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN); 115 116 out: 117 __this_cpu_dec(bpf_prog_active); 118 preempt_enable(); 119 120 return ret; 121 } 122 EXPORT_SYMBOL_GPL(trace_call_bpf); 123 124 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 125 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) 126 { 127 regs_set_return_value(regs, rc); 128 override_function_with_return(regs); 129 return 0; 130 } 131 132 static const struct bpf_func_proto bpf_override_return_proto = { 133 .func = bpf_override_return, 134 .gpl_only = true, 135 .ret_type = RET_INTEGER, 136 .arg1_type = ARG_PTR_TO_CTX, 137 .arg2_type = ARG_ANYTHING, 138 }; 139 #endif 140 141 BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size, 142 const void __user *, unsafe_ptr) 143 { 144 int ret = probe_user_read(dst, unsafe_ptr, size); 145 146 if (unlikely(ret < 0)) 147 memset(dst, 0, size); 148 149 return ret; 150 } 151 152 static const struct bpf_func_proto bpf_probe_read_user_proto = { 153 .func = bpf_probe_read_user, 154 .gpl_only = true, 155 .ret_type = RET_INTEGER, 156 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 157 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 158 .arg3_type = ARG_ANYTHING, 159 }; 160 161 BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size, 162 const void __user *, unsafe_ptr) 163 { 164 int ret = strncpy_from_unsafe_user(dst, unsafe_ptr, size); 165 166 if (unlikely(ret < 0)) 167 memset(dst, 0, size); 168 169 return ret; 170 } 171 172 static const struct bpf_func_proto bpf_probe_read_user_str_proto = { 173 .func = bpf_probe_read_user_str, 174 .gpl_only = true, 175 .ret_type = RET_INTEGER, 176 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 177 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 178 .arg3_type = ARG_ANYTHING, 179 }; 180 181 static __always_inline int 182 bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr, 183 const bool compat) 184 { 185 int ret = security_locked_down(LOCKDOWN_BPF_READ); 186 187 if (unlikely(ret < 0)) 188 goto out; 189 ret = compat ? probe_kernel_read(dst, unsafe_ptr, size) : 190 probe_kernel_read_strict(dst, unsafe_ptr, size); 191 if (unlikely(ret < 0)) 192 out: 193 memset(dst, 0, size); 194 return ret; 195 } 196 197 BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size, 198 const void *, unsafe_ptr) 199 { 200 return bpf_probe_read_kernel_common(dst, size, unsafe_ptr, false); 201 } 202 203 static const struct bpf_func_proto bpf_probe_read_kernel_proto = { 204 .func = bpf_probe_read_kernel, 205 .gpl_only = true, 206 .ret_type = RET_INTEGER, 207 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 208 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 209 .arg3_type = ARG_ANYTHING, 210 }; 211 212 BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size, 213 const void *, unsafe_ptr) 214 { 215 return bpf_probe_read_kernel_common(dst, size, unsafe_ptr, true); 216 } 217 218 static const struct bpf_func_proto bpf_probe_read_compat_proto = { 219 .func = bpf_probe_read_compat, 220 .gpl_only = true, 221 .ret_type = RET_INTEGER, 222 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 223 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 224 .arg3_type = ARG_ANYTHING, 225 }; 226 227 static __always_inline int 228 bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr, 229 const bool compat) 230 { 231 int ret = security_locked_down(LOCKDOWN_BPF_READ); 232 233 if (unlikely(ret < 0)) 234 goto out; 235 /* 236 * The strncpy_from_unsafe_*() call will likely not fill the entire 237 * buffer, but that's okay in this circumstance as we're probing 238 * arbitrary memory anyway similar to bpf_probe_read_*() and might 239 * as well probe the stack. Thus, memory is explicitly cleared 240 * only in error case, so that improper users ignoring return 241 * code altogether don't copy garbage; otherwise length of string 242 * is returned that can be used for bpf_perf_event_output() et al. 243 */ 244 ret = compat ? strncpy_from_unsafe(dst, unsafe_ptr, size) : 245 strncpy_from_unsafe_strict(dst, unsafe_ptr, size); 246 if (unlikely(ret < 0)) 247 out: 248 memset(dst, 0, size); 249 return ret; 250 } 251 252 BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size, 253 const void *, unsafe_ptr) 254 { 255 return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr, false); 256 } 257 258 static const struct bpf_func_proto bpf_probe_read_kernel_str_proto = { 259 .func = bpf_probe_read_kernel_str, 260 .gpl_only = true, 261 .ret_type = RET_INTEGER, 262 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 263 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 264 .arg3_type = ARG_ANYTHING, 265 }; 266 267 BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size, 268 const void *, unsafe_ptr) 269 { 270 return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr, true); 271 } 272 273 static const struct bpf_func_proto bpf_probe_read_compat_str_proto = { 274 .func = bpf_probe_read_compat_str, 275 .gpl_only = true, 276 .ret_type = RET_INTEGER, 277 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 278 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 279 .arg3_type = ARG_ANYTHING, 280 }; 281 282 BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src, 283 u32, size) 284 { 285 /* 286 * Ensure we're in user context which is safe for the helper to 287 * run. This helper has no business in a kthread. 288 * 289 * access_ok() should prevent writing to non-user memory, but in 290 * some situations (nommu, temporary switch, etc) access_ok() does 291 * not provide enough validation, hence the check on KERNEL_DS. 292 * 293 * nmi_uaccess_okay() ensures the probe is not run in an interim 294 * state, when the task or mm are switched. This is specifically 295 * required to prevent the use of temporary mm. 296 */ 297 298 if (unlikely(in_interrupt() || 299 current->flags & (PF_KTHREAD | PF_EXITING))) 300 return -EPERM; 301 if (unlikely(uaccess_kernel())) 302 return -EPERM; 303 if (unlikely(!nmi_uaccess_okay())) 304 return -EPERM; 305 306 return probe_user_write(unsafe_ptr, src, size); 307 } 308 309 static const struct bpf_func_proto bpf_probe_write_user_proto = { 310 .func = bpf_probe_write_user, 311 .gpl_only = true, 312 .ret_type = RET_INTEGER, 313 .arg1_type = ARG_ANYTHING, 314 .arg2_type = ARG_PTR_TO_MEM, 315 .arg3_type = ARG_CONST_SIZE, 316 }; 317 318 static const struct bpf_func_proto *bpf_get_probe_write_proto(void) 319 { 320 pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", 321 current->comm, task_pid_nr(current)); 322 323 return &bpf_probe_write_user_proto; 324 } 325 326 /* 327 * Only limited trace_printk() conversion specifiers allowed: 328 * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s 329 */ 330 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, 331 u64, arg2, u64, arg3) 332 { 333 bool str_seen = false; 334 int mod[3] = {}; 335 int fmt_cnt = 0; 336 u64 unsafe_addr; 337 char buf[64]; 338 int i; 339 340 /* 341 * bpf_check()->check_func_arg()->check_stack_boundary() 342 * guarantees that fmt points to bpf program stack, 343 * fmt_size bytes of it were initialized and fmt_size > 0 344 */ 345 if (fmt[--fmt_size] != 0) 346 return -EINVAL; 347 348 /* check format string for allowed specifiers */ 349 for (i = 0; i < fmt_size; i++) { 350 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) 351 return -EINVAL; 352 353 if (fmt[i] != '%') 354 continue; 355 356 if (fmt_cnt >= 3) 357 return -EINVAL; 358 359 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ 360 i++; 361 if (fmt[i] == 'l') { 362 mod[fmt_cnt]++; 363 i++; 364 } else if (fmt[i] == 'p' || fmt[i] == 's') { 365 mod[fmt_cnt]++; 366 /* disallow any further format extensions */ 367 if (fmt[i + 1] != 0 && 368 !isspace(fmt[i + 1]) && 369 !ispunct(fmt[i + 1])) 370 return -EINVAL; 371 fmt_cnt++; 372 if (fmt[i] == 's') { 373 if (str_seen) 374 /* allow only one '%s' per fmt string */ 375 return -EINVAL; 376 str_seen = true; 377 378 switch (fmt_cnt) { 379 case 1: 380 unsafe_addr = arg1; 381 arg1 = (long) buf; 382 break; 383 case 2: 384 unsafe_addr = arg2; 385 arg2 = (long) buf; 386 break; 387 case 3: 388 unsafe_addr = arg3; 389 arg3 = (long) buf; 390 break; 391 } 392 buf[0] = 0; 393 strncpy_from_unsafe(buf, 394 (void *) (long) unsafe_addr, 395 sizeof(buf)); 396 } 397 continue; 398 } 399 400 if (fmt[i] == 'l') { 401 mod[fmt_cnt]++; 402 i++; 403 } 404 405 if (fmt[i] != 'i' && fmt[i] != 'd' && 406 fmt[i] != 'u' && fmt[i] != 'x') 407 return -EINVAL; 408 fmt_cnt++; 409 } 410 411 /* Horrid workaround for getting va_list handling working with different 412 * argument type combinations generically for 32 and 64 bit archs. 413 */ 414 #define __BPF_TP_EMIT() __BPF_ARG3_TP() 415 #define __BPF_TP(...) \ 416 __trace_printk(0 /* Fake ip */, \ 417 fmt, ##__VA_ARGS__) 418 419 #define __BPF_ARG1_TP(...) \ 420 ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ 421 ? __BPF_TP(arg1, ##__VA_ARGS__) \ 422 : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ 423 ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ 424 : __BPF_TP((u32)arg1, ##__VA_ARGS__))) 425 426 #define __BPF_ARG2_TP(...) \ 427 ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ 428 ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ 429 : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ 430 ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ 431 : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) 432 433 #define __BPF_ARG3_TP(...) \ 434 ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ 435 ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ 436 : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ 437 ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ 438 : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) 439 440 return __BPF_TP_EMIT(); 441 } 442 443 static const struct bpf_func_proto bpf_trace_printk_proto = { 444 .func = bpf_trace_printk, 445 .gpl_only = true, 446 .ret_type = RET_INTEGER, 447 .arg1_type = ARG_PTR_TO_MEM, 448 .arg2_type = ARG_CONST_SIZE, 449 }; 450 451 const struct bpf_func_proto *bpf_get_trace_printk_proto(void) 452 { 453 /* 454 * this program might be calling bpf_trace_printk, 455 * so allocate per-cpu printk buffers 456 */ 457 trace_printk_init_buffers(); 458 459 return &bpf_trace_printk_proto; 460 } 461 462 static __always_inline int 463 get_map_perf_counter(struct bpf_map *map, u64 flags, 464 u64 *value, u64 *enabled, u64 *running) 465 { 466 struct bpf_array *array = container_of(map, struct bpf_array, map); 467 unsigned int cpu = smp_processor_id(); 468 u64 index = flags & BPF_F_INDEX_MASK; 469 struct bpf_event_entry *ee; 470 471 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) 472 return -EINVAL; 473 if (index == BPF_F_CURRENT_CPU) 474 index = cpu; 475 if (unlikely(index >= array->map.max_entries)) 476 return -E2BIG; 477 478 ee = READ_ONCE(array->ptrs[index]); 479 if (!ee) 480 return -ENOENT; 481 482 return perf_event_read_local(ee->event, value, enabled, running); 483 } 484 485 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) 486 { 487 u64 value = 0; 488 int err; 489 490 err = get_map_perf_counter(map, flags, &value, NULL, NULL); 491 /* 492 * this api is ugly since we miss [-22..-2] range of valid 493 * counter values, but that's uapi 494 */ 495 if (err) 496 return err; 497 return value; 498 } 499 500 static const struct bpf_func_proto bpf_perf_event_read_proto = { 501 .func = bpf_perf_event_read, 502 .gpl_only = true, 503 .ret_type = RET_INTEGER, 504 .arg1_type = ARG_CONST_MAP_PTR, 505 .arg2_type = ARG_ANYTHING, 506 }; 507 508 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags, 509 struct bpf_perf_event_value *, buf, u32, size) 510 { 511 int err = -EINVAL; 512 513 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 514 goto clear; 515 err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled, 516 &buf->running); 517 if (unlikely(err)) 518 goto clear; 519 return 0; 520 clear: 521 memset(buf, 0, size); 522 return err; 523 } 524 525 static const struct bpf_func_proto bpf_perf_event_read_value_proto = { 526 .func = bpf_perf_event_read_value, 527 .gpl_only = true, 528 .ret_type = RET_INTEGER, 529 .arg1_type = ARG_CONST_MAP_PTR, 530 .arg2_type = ARG_ANYTHING, 531 .arg3_type = ARG_PTR_TO_UNINIT_MEM, 532 .arg4_type = ARG_CONST_SIZE, 533 }; 534 535 static __always_inline u64 536 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, 537 u64 flags, struct perf_sample_data *sd) 538 { 539 struct bpf_array *array = container_of(map, struct bpf_array, map); 540 unsigned int cpu = smp_processor_id(); 541 u64 index = flags & BPF_F_INDEX_MASK; 542 struct bpf_event_entry *ee; 543 struct perf_event *event; 544 545 if (index == BPF_F_CURRENT_CPU) 546 index = cpu; 547 if (unlikely(index >= array->map.max_entries)) 548 return -E2BIG; 549 550 ee = READ_ONCE(array->ptrs[index]); 551 if (!ee) 552 return -ENOENT; 553 554 event = ee->event; 555 if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || 556 event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) 557 return -EINVAL; 558 559 if (unlikely(event->oncpu != cpu)) 560 return -EOPNOTSUPP; 561 562 return perf_event_output(event, sd, regs); 563 } 564 565 /* 566 * Support executing tracepoints in normal, irq, and nmi context that each call 567 * bpf_perf_event_output 568 */ 569 struct bpf_trace_sample_data { 570 struct perf_sample_data sds[3]; 571 }; 572 573 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); 574 static DEFINE_PER_CPU(int, bpf_trace_nest_level); 575 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, 576 u64, flags, void *, data, u64, size) 577 { 578 struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds); 579 int nest_level = this_cpu_inc_return(bpf_trace_nest_level); 580 struct perf_raw_record raw = { 581 .frag = { 582 .size = size, 583 .data = data, 584 }, 585 }; 586 struct perf_sample_data *sd; 587 int err; 588 589 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { 590 err = -EBUSY; 591 goto out; 592 } 593 594 sd = &sds->sds[nest_level - 1]; 595 596 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { 597 err = -EINVAL; 598 goto out; 599 } 600 601 perf_sample_data_init(sd, 0, 0); 602 sd->raw = &raw; 603 604 err = __bpf_perf_event_output(regs, map, flags, sd); 605 606 out: 607 this_cpu_dec(bpf_trace_nest_level); 608 return err; 609 } 610 611 static const struct bpf_func_proto bpf_perf_event_output_proto = { 612 .func = bpf_perf_event_output, 613 .gpl_only = true, 614 .ret_type = RET_INTEGER, 615 .arg1_type = ARG_PTR_TO_CTX, 616 .arg2_type = ARG_CONST_MAP_PTR, 617 .arg3_type = ARG_ANYTHING, 618 .arg4_type = ARG_PTR_TO_MEM, 619 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 620 }; 621 622 static DEFINE_PER_CPU(int, bpf_event_output_nest_level); 623 struct bpf_nested_pt_regs { 624 struct pt_regs regs[3]; 625 }; 626 static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs); 627 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds); 628 629 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 630 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 631 { 632 int nest_level = this_cpu_inc_return(bpf_event_output_nest_level); 633 struct perf_raw_frag frag = { 634 .copy = ctx_copy, 635 .size = ctx_size, 636 .data = ctx, 637 }; 638 struct perf_raw_record raw = { 639 .frag = { 640 { 641 .next = ctx_size ? &frag : NULL, 642 }, 643 .size = meta_size, 644 .data = meta, 645 }, 646 }; 647 struct perf_sample_data *sd; 648 struct pt_regs *regs; 649 u64 ret; 650 651 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) { 652 ret = -EBUSY; 653 goto out; 654 } 655 sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]); 656 regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]); 657 658 perf_fetch_caller_regs(regs); 659 perf_sample_data_init(sd, 0, 0); 660 sd->raw = &raw; 661 662 ret = __bpf_perf_event_output(regs, map, flags, sd); 663 out: 664 this_cpu_dec(bpf_event_output_nest_level); 665 return ret; 666 } 667 668 BPF_CALL_0(bpf_get_current_task) 669 { 670 return (long) current; 671 } 672 673 static const struct bpf_func_proto bpf_get_current_task_proto = { 674 .func = bpf_get_current_task, 675 .gpl_only = true, 676 .ret_type = RET_INTEGER, 677 }; 678 679 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) 680 { 681 struct bpf_array *array = container_of(map, struct bpf_array, map); 682 struct cgroup *cgrp; 683 684 if (unlikely(idx >= array->map.max_entries)) 685 return -E2BIG; 686 687 cgrp = READ_ONCE(array->ptrs[idx]); 688 if (unlikely(!cgrp)) 689 return -EAGAIN; 690 691 return task_under_cgroup_hierarchy(current, cgrp); 692 } 693 694 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { 695 .func = bpf_current_task_under_cgroup, 696 .gpl_only = false, 697 .ret_type = RET_INTEGER, 698 .arg1_type = ARG_CONST_MAP_PTR, 699 .arg2_type = ARG_ANYTHING, 700 }; 701 702 struct send_signal_irq_work { 703 struct irq_work irq_work; 704 struct task_struct *task; 705 u32 sig; 706 enum pid_type type; 707 }; 708 709 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); 710 711 static void do_bpf_send_signal(struct irq_work *entry) 712 { 713 struct send_signal_irq_work *work; 714 715 work = container_of(entry, struct send_signal_irq_work, irq_work); 716 group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type); 717 } 718 719 static int bpf_send_signal_common(u32 sig, enum pid_type type) 720 { 721 struct send_signal_irq_work *work = NULL; 722 723 /* Similar to bpf_probe_write_user, task needs to be 724 * in a sound condition and kernel memory access be 725 * permitted in order to send signal to the current 726 * task. 727 */ 728 if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) 729 return -EPERM; 730 if (unlikely(uaccess_kernel())) 731 return -EPERM; 732 if (unlikely(!nmi_uaccess_okay())) 733 return -EPERM; 734 735 if (in_nmi()) { 736 /* Do an early check on signal validity. Otherwise, 737 * the error is lost in deferred irq_work. 738 */ 739 if (unlikely(!valid_signal(sig))) 740 return -EINVAL; 741 742 work = this_cpu_ptr(&send_signal_work); 743 if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY) 744 return -EBUSY; 745 746 /* Add the current task, which is the target of sending signal, 747 * to the irq_work. The current task may change when queued 748 * irq works get executed. 749 */ 750 work->task = current; 751 work->sig = sig; 752 work->type = type; 753 irq_work_queue(&work->irq_work); 754 return 0; 755 } 756 757 return group_send_sig_info(sig, SEND_SIG_PRIV, current, type); 758 } 759 760 BPF_CALL_1(bpf_send_signal, u32, sig) 761 { 762 return bpf_send_signal_common(sig, PIDTYPE_TGID); 763 } 764 765 static const struct bpf_func_proto bpf_send_signal_proto = { 766 .func = bpf_send_signal, 767 .gpl_only = false, 768 .ret_type = RET_INTEGER, 769 .arg1_type = ARG_ANYTHING, 770 }; 771 772 BPF_CALL_1(bpf_send_signal_thread, u32, sig) 773 { 774 return bpf_send_signal_common(sig, PIDTYPE_PID); 775 } 776 777 static const struct bpf_func_proto bpf_send_signal_thread_proto = { 778 .func = bpf_send_signal_thread, 779 .gpl_only = false, 780 .ret_type = RET_INTEGER, 781 .arg1_type = ARG_ANYTHING, 782 }; 783 784 static const struct bpf_func_proto * 785 tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 786 { 787 switch (func_id) { 788 case BPF_FUNC_map_lookup_elem: 789 return &bpf_map_lookup_elem_proto; 790 case BPF_FUNC_map_update_elem: 791 return &bpf_map_update_elem_proto; 792 case BPF_FUNC_map_delete_elem: 793 return &bpf_map_delete_elem_proto; 794 case BPF_FUNC_map_push_elem: 795 return &bpf_map_push_elem_proto; 796 case BPF_FUNC_map_pop_elem: 797 return &bpf_map_pop_elem_proto; 798 case BPF_FUNC_map_peek_elem: 799 return &bpf_map_peek_elem_proto; 800 case BPF_FUNC_ktime_get_ns: 801 return &bpf_ktime_get_ns_proto; 802 case BPF_FUNC_tail_call: 803 return &bpf_tail_call_proto; 804 case BPF_FUNC_get_current_pid_tgid: 805 return &bpf_get_current_pid_tgid_proto; 806 case BPF_FUNC_get_current_task: 807 return &bpf_get_current_task_proto; 808 case BPF_FUNC_get_current_uid_gid: 809 return &bpf_get_current_uid_gid_proto; 810 case BPF_FUNC_get_current_comm: 811 return &bpf_get_current_comm_proto; 812 case BPF_FUNC_trace_printk: 813 return bpf_get_trace_printk_proto(); 814 case BPF_FUNC_get_smp_processor_id: 815 return &bpf_get_smp_processor_id_proto; 816 case BPF_FUNC_get_numa_node_id: 817 return &bpf_get_numa_node_id_proto; 818 case BPF_FUNC_perf_event_read: 819 return &bpf_perf_event_read_proto; 820 case BPF_FUNC_probe_write_user: 821 return bpf_get_probe_write_proto(); 822 case BPF_FUNC_current_task_under_cgroup: 823 return &bpf_current_task_under_cgroup_proto; 824 case BPF_FUNC_get_prandom_u32: 825 return &bpf_get_prandom_u32_proto; 826 case BPF_FUNC_probe_read_user: 827 return &bpf_probe_read_user_proto; 828 case BPF_FUNC_probe_read_kernel: 829 return &bpf_probe_read_kernel_proto; 830 case BPF_FUNC_probe_read: 831 return &bpf_probe_read_compat_proto; 832 case BPF_FUNC_probe_read_user_str: 833 return &bpf_probe_read_user_str_proto; 834 case BPF_FUNC_probe_read_kernel_str: 835 return &bpf_probe_read_kernel_str_proto; 836 case BPF_FUNC_probe_read_str: 837 return &bpf_probe_read_compat_str_proto; 838 #ifdef CONFIG_CGROUPS 839 case BPF_FUNC_get_current_cgroup_id: 840 return &bpf_get_current_cgroup_id_proto; 841 #endif 842 case BPF_FUNC_send_signal: 843 return &bpf_send_signal_proto; 844 case BPF_FUNC_send_signal_thread: 845 return &bpf_send_signal_thread_proto; 846 default: 847 return NULL; 848 } 849 } 850 851 static const struct bpf_func_proto * 852 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 853 { 854 switch (func_id) { 855 case BPF_FUNC_perf_event_output: 856 return &bpf_perf_event_output_proto; 857 case BPF_FUNC_get_stackid: 858 return &bpf_get_stackid_proto; 859 case BPF_FUNC_get_stack: 860 return &bpf_get_stack_proto; 861 case BPF_FUNC_perf_event_read_value: 862 return &bpf_perf_event_read_value_proto; 863 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 864 case BPF_FUNC_override_return: 865 return &bpf_override_return_proto; 866 #endif 867 default: 868 return tracing_func_proto(func_id, prog); 869 } 870 } 871 872 /* bpf+kprobe programs can access fields of 'struct pt_regs' */ 873 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 874 const struct bpf_prog *prog, 875 struct bpf_insn_access_aux *info) 876 { 877 if (off < 0 || off >= sizeof(struct pt_regs)) 878 return false; 879 if (type != BPF_READ) 880 return false; 881 if (off % size != 0) 882 return false; 883 /* 884 * Assertion for 32 bit to make sure last 8 byte access 885 * (BPF_DW) to the last 4 byte member is disallowed. 886 */ 887 if (off + size > sizeof(struct pt_regs)) 888 return false; 889 890 return true; 891 } 892 893 const struct bpf_verifier_ops kprobe_verifier_ops = { 894 .get_func_proto = kprobe_prog_func_proto, 895 .is_valid_access = kprobe_prog_is_valid_access, 896 }; 897 898 const struct bpf_prog_ops kprobe_prog_ops = { 899 }; 900 901 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, 902 u64, flags, void *, data, u64, size) 903 { 904 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 905 906 /* 907 * r1 points to perf tracepoint buffer where first 8 bytes are hidden 908 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it 909 * from there and call the same bpf_perf_event_output() helper inline. 910 */ 911 return ____bpf_perf_event_output(regs, map, flags, data, size); 912 } 913 914 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { 915 .func = bpf_perf_event_output_tp, 916 .gpl_only = true, 917 .ret_type = RET_INTEGER, 918 .arg1_type = ARG_PTR_TO_CTX, 919 .arg2_type = ARG_CONST_MAP_PTR, 920 .arg3_type = ARG_ANYTHING, 921 .arg4_type = ARG_PTR_TO_MEM, 922 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 923 }; 924 925 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, 926 u64, flags) 927 { 928 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 929 930 /* 931 * Same comment as in bpf_perf_event_output_tp(), only that this time 932 * the other helper's function body cannot be inlined due to being 933 * external, thus we need to call raw helper function. 934 */ 935 return bpf_get_stackid((unsigned long) regs, (unsigned long) map, 936 flags, 0, 0); 937 } 938 939 static const struct bpf_func_proto bpf_get_stackid_proto_tp = { 940 .func = bpf_get_stackid_tp, 941 .gpl_only = true, 942 .ret_type = RET_INTEGER, 943 .arg1_type = ARG_PTR_TO_CTX, 944 .arg2_type = ARG_CONST_MAP_PTR, 945 .arg3_type = ARG_ANYTHING, 946 }; 947 948 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size, 949 u64, flags) 950 { 951 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 952 953 return bpf_get_stack((unsigned long) regs, (unsigned long) buf, 954 (unsigned long) size, flags, 0); 955 } 956 957 static const struct bpf_func_proto bpf_get_stack_proto_tp = { 958 .func = bpf_get_stack_tp, 959 .gpl_only = true, 960 .ret_type = RET_INTEGER, 961 .arg1_type = ARG_PTR_TO_CTX, 962 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 963 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 964 .arg4_type = ARG_ANYTHING, 965 }; 966 967 static const struct bpf_func_proto * 968 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 969 { 970 switch (func_id) { 971 case BPF_FUNC_perf_event_output: 972 return &bpf_perf_event_output_proto_tp; 973 case BPF_FUNC_get_stackid: 974 return &bpf_get_stackid_proto_tp; 975 case BPF_FUNC_get_stack: 976 return &bpf_get_stack_proto_tp; 977 default: 978 return tracing_func_proto(func_id, prog); 979 } 980 } 981 982 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, 983 const struct bpf_prog *prog, 984 struct bpf_insn_access_aux *info) 985 { 986 if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) 987 return false; 988 if (type != BPF_READ) 989 return false; 990 if (off % size != 0) 991 return false; 992 993 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); 994 return true; 995 } 996 997 const struct bpf_verifier_ops tracepoint_verifier_ops = { 998 .get_func_proto = tp_prog_func_proto, 999 .is_valid_access = tp_prog_is_valid_access, 1000 }; 1001 1002 const struct bpf_prog_ops tracepoint_prog_ops = { 1003 }; 1004 1005 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx, 1006 struct bpf_perf_event_value *, buf, u32, size) 1007 { 1008 int err = -EINVAL; 1009 1010 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 1011 goto clear; 1012 err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, 1013 &buf->running); 1014 if (unlikely(err)) 1015 goto clear; 1016 return 0; 1017 clear: 1018 memset(buf, 0, size); 1019 return err; 1020 } 1021 1022 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { 1023 .func = bpf_perf_prog_read_value, 1024 .gpl_only = true, 1025 .ret_type = RET_INTEGER, 1026 .arg1_type = ARG_PTR_TO_CTX, 1027 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 1028 .arg3_type = ARG_CONST_SIZE, 1029 }; 1030 1031 static const struct bpf_func_proto * 1032 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1033 { 1034 switch (func_id) { 1035 case BPF_FUNC_perf_event_output: 1036 return &bpf_perf_event_output_proto_tp; 1037 case BPF_FUNC_get_stackid: 1038 return &bpf_get_stackid_proto_tp; 1039 case BPF_FUNC_get_stack: 1040 return &bpf_get_stack_proto_tp; 1041 case BPF_FUNC_perf_prog_read_value: 1042 return &bpf_perf_prog_read_value_proto; 1043 default: 1044 return tracing_func_proto(func_id, prog); 1045 } 1046 } 1047 1048 /* 1049 * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp 1050 * to avoid potential recursive reuse issue when/if tracepoints are added 1051 * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. 1052 * 1053 * Since raw tracepoints run despite bpf_prog_active, support concurrent usage 1054 * in normal, irq, and nmi context. 1055 */ 1056 struct bpf_raw_tp_regs { 1057 struct pt_regs regs[3]; 1058 }; 1059 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); 1060 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); 1061 static struct pt_regs *get_bpf_raw_tp_regs(void) 1062 { 1063 struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); 1064 int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); 1065 1066 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { 1067 this_cpu_dec(bpf_raw_tp_nest_level); 1068 return ERR_PTR(-EBUSY); 1069 } 1070 1071 return &tp_regs->regs[nest_level - 1]; 1072 } 1073 1074 static void put_bpf_raw_tp_regs(void) 1075 { 1076 this_cpu_dec(bpf_raw_tp_nest_level); 1077 } 1078 1079 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, 1080 struct bpf_map *, map, u64, flags, void *, data, u64, size) 1081 { 1082 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1083 int ret; 1084 1085 if (IS_ERR(regs)) 1086 return PTR_ERR(regs); 1087 1088 perf_fetch_caller_regs(regs); 1089 ret = ____bpf_perf_event_output(regs, map, flags, data, size); 1090 1091 put_bpf_raw_tp_regs(); 1092 return ret; 1093 } 1094 1095 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { 1096 .func = bpf_perf_event_output_raw_tp, 1097 .gpl_only = true, 1098 .ret_type = RET_INTEGER, 1099 .arg1_type = ARG_PTR_TO_CTX, 1100 .arg2_type = ARG_CONST_MAP_PTR, 1101 .arg3_type = ARG_ANYTHING, 1102 .arg4_type = ARG_PTR_TO_MEM, 1103 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 1104 }; 1105 1106 extern const struct bpf_func_proto bpf_skb_output_proto; 1107 1108 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, 1109 struct bpf_map *, map, u64, flags) 1110 { 1111 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1112 int ret; 1113 1114 if (IS_ERR(regs)) 1115 return PTR_ERR(regs); 1116 1117 perf_fetch_caller_regs(regs); 1118 /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ 1119 ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, 1120 flags, 0, 0); 1121 put_bpf_raw_tp_regs(); 1122 return ret; 1123 } 1124 1125 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { 1126 .func = bpf_get_stackid_raw_tp, 1127 .gpl_only = true, 1128 .ret_type = RET_INTEGER, 1129 .arg1_type = ARG_PTR_TO_CTX, 1130 .arg2_type = ARG_CONST_MAP_PTR, 1131 .arg3_type = ARG_ANYTHING, 1132 }; 1133 1134 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, 1135 void *, buf, u32, size, u64, flags) 1136 { 1137 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1138 int ret; 1139 1140 if (IS_ERR(regs)) 1141 return PTR_ERR(regs); 1142 1143 perf_fetch_caller_regs(regs); 1144 ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, 1145 (unsigned long) size, flags, 0); 1146 put_bpf_raw_tp_regs(); 1147 return ret; 1148 } 1149 1150 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { 1151 .func = bpf_get_stack_raw_tp, 1152 .gpl_only = true, 1153 .ret_type = RET_INTEGER, 1154 .arg1_type = ARG_PTR_TO_CTX, 1155 .arg2_type = ARG_PTR_TO_MEM, 1156 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1157 .arg4_type = ARG_ANYTHING, 1158 }; 1159 1160 static const struct bpf_func_proto * 1161 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1162 { 1163 switch (func_id) { 1164 case BPF_FUNC_perf_event_output: 1165 return &bpf_perf_event_output_proto_raw_tp; 1166 case BPF_FUNC_get_stackid: 1167 return &bpf_get_stackid_proto_raw_tp; 1168 case BPF_FUNC_get_stack: 1169 return &bpf_get_stack_proto_raw_tp; 1170 default: 1171 return tracing_func_proto(func_id, prog); 1172 } 1173 } 1174 1175 static const struct bpf_func_proto * 1176 tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1177 { 1178 switch (func_id) { 1179 #ifdef CONFIG_NET 1180 case BPF_FUNC_skb_output: 1181 return &bpf_skb_output_proto; 1182 #endif 1183 default: 1184 return raw_tp_prog_func_proto(func_id, prog); 1185 } 1186 } 1187 1188 static bool raw_tp_prog_is_valid_access(int off, int size, 1189 enum bpf_access_type type, 1190 const struct bpf_prog *prog, 1191 struct bpf_insn_access_aux *info) 1192 { 1193 if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) 1194 return false; 1195 if (type != BPF_READ) 1196 return false; 1197 if (off % size != 0) 1198 return false; 1199 return true; 1200 } 1201 1202 static bool tracing_prog_is_valid_access(int off, int size, 1203 enum bpf_access_type type, 1204 const struct bpf_prog *prog, 1205 struct bpf_insn_access_aux *info) 1206 { 1207 if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) 1208 return false; 1209 if (type != BPF_READ) 1210 return false; 1211 if (off % size != 0) 1212 return false; 1213 return btf_ctx_access(off, size, type, prog, info); 1214 } 1215 1216 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { 1217 .get_func_proto = raw_tp_prog_func_proto, 1218 .is_valid_access = raw_tp_prog_is_valid_access, 1219 }; 1220 1221 const struct bpf_prog_ops raw_tracepoint_prog_ops = { 1222 }; 1223 1224 const struct bpf_verifier_ops tracing_verifier_ops = { 1225 .get_func_proto = tracing_prog_func_proto, 1226 .is_valid_access = tracing_prog_is_valid_access, 1227 }; 1228 1229 const struct bpf_prog_ops tracing_prog_ops = { 1230 }; 1231 1232 static bool raw_tp_writable_prog_is_valid_access(int off, int size, 1233 enum bpf_access_type type, 1234 const struct bpf_prog *prog, 1235 struct bpf_insn_access_aux *info) 1236 { 1237 if (off == 0) { 1238 if (size != sizeof(u64) || type != BPF_READ) 1239 return false; 1240 info->reg_type = PTR_TO_TP_BUFFER; 1241 } 1242 return raw_tp_prog_is_valid_access(off, size, type, prog, info); 1243 } 1244 1245 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { 1246 .get_func_proto = raw_tp_prog_func_proto, 1247 .is_valid_access = raw_tp_writable_prog_is_valid_access, 1248 }; 1249 1250 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { 1251 }; 1252 1253 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1254 const struct bpf_prog *prog, 1255 struct bpf_insn_access_aux *info) 1256 { 1257 const int size_u64 = sizeof(u64); 1258 1259 if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) 1260 return false; 1261 if (type != BPF_READ) 1262 return false; 1263 if (off % size != 0) { 1264 if (sizeof(unsigned long) != 4) 1265 return false; 1266 if (size != 8) 1267 return false; 1268 if (off % size != 4) 1269 return false; 1270 } 1271 1272 switch (off) { 1273 case bpf_ctx_range(struct bpf_perf_event_data, sample_period): 1274 bpf_ctx_record_field_size(info, size_u64); 1275 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1276 return false; 1277 break; 1278 case bpf_ctx_range(struct bpf_perf_event_data, addr): 1279 bpf_ctx_record_field_size(info, size_u64); 1280 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1281 return false; 1282 break; 1283 default: 1284 if (size != sizeof(long)) 1285 return false; 1286 } 1287 1288 return true; 1289 } 1290 1291 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, 1292 const struct bpf_insn *si, 1293 struct bpf_insn *insn_buf, 1294 struct bpf_prog *prog, u32 *target_size) 1295 { 1296 struct bpf_insn *insn = insn_buf; 1297 1298 switch (si->off) { 1299 case offsetof(struct bpf_perf_event_data, sample_period): 1300 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1301 data), si->dst_reg, si->src_reg, 1302 offsetof(struct bpf_perf_event_data_kern, data)); 1303 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1304 bpf_target_off(struct perf_sample_data, period, 8, 1305 target_size)); 1306 break; 1307 case offsetof(struct bpf_perf_event_data, addr): 1308 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1309 data), si->dst_reg, si->src_reg, 1310 offsetof(struct bpf_perf_event_data_kern, data)); 1311 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1312 bpf_target_off(struct perf_sample_data, addr, 8, 1313 target_size)); 1314 break; 1315 default: 1316 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1317 regs), si->dst_reg, si->src_reg, 1318 offsetof(struct bpf_perf_event_data_kern, regs)); 1319 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, 1320 si->off); 1321 break; 1322 } 1323 1324 return insn - insn_buf; 1325 } 1326 1327 const struct bpf_verifier_ops perf_event_verifier_ops = { 1328 .get_func_proto = pe_prog_func_proto, 1329 .is_valid_access = pe_prog_is_valid_access, 1330 .convert_ctx_access = pe_prog_convert_ctx_access, 1331 }; 1332 1333 const struct bpf_prog_ops perf_event_prog_ops = { 1334 }; 1335 1336 static DEFINE_MUTEX(bpf_event_mutex); 1337 1338 #define BPF_TRACE_MAX_PROGS 64 1339 1340 int perf_event_attach_bpf_prog(struct perf_event *event, 1341 struct bpf_prog *prog) 1342 { 1343 struct bpf_prog_array *old_array; 1344 struct bpf_prog_array *new_array; 1345 int ret = -EEXIST; 1346 1347 /* 1348 * Kprobe override only works if they are on the function entry, 1349 * and only if they are on the opt-in list. 1350 */ 1351 if (prog->kprobe_override && 1352 (!trace_kprobe_on_func_entry(event->tp_event) || 1353 !trace_kprobe_error_injectable(event->tp_event))) 1354 return -EINVAL; 1355 1356 mutex_lock(&bpf_event_mutex); 1357 1358 if (event->prog) 1359 goto unlock; 1360 1361 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1362 if (old_array && 1363 bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { 1364 ret = -E2BIG; 1365 goto unlock; 1366 } 1367 1368 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); 1369 if (ret < 0) 1370 goto unlock; 1371 1372 /* set the new array to event->tp_event and set event->prog */ 1373 event->prog = prog; 1374 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1375 bpf_prog_array_free(old_array); 1376 1377 unlock: 1378 mutex_unlock(&bpf_event_mutex); 1379 return ret; 1380 } 1381 1382 void perf_event_detach_bpf_prog(struct perf_event *event) 1383 { 1384 struct bpf_prog_array *old_array; 1385 struct bpf_prog_array *new_array; 1386 int ret; 1387 1388 mutex_lock(&bpf_event_mutex); 1389 1390 if (!event->prog) 1391 goto unlock; 1392 1393 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1394 ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); 1395 if (ret == -ENOENT) 1396 goto unlock; 1397 if (ret < 0) { 1398 bpf_prog_array_delete_safe(old_array, event->prog); 1399 } else { 1400 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1401 bpf_prog_array_free(old_array); 1402 } 1403 1404 bpf_prog_put(event->prog); 1405 event->prog = NULL; 1406 1407 unlock: 1408 mutex_unlock(&bpf_event_mutex); 1409 } 1410 1411 int perf_event_query_prog_array(struct perf_event *event, void __user *info) 1412 { 1413 struct perf_event_query_bpf __user *uquery = info; 1414 struct perf_event_query_bpf query = {}; 1415 struct bpf_prog_array *progs; 1416 u32 *ids, prog_cnt, ids_len; 1417 int ret; 1418 1419 if (!capable(CAP_SYS_ADMIN)) 1420 return -EPERM; 1421 if (event->attr.type != PERF_TYPE_TRACEPOINT) 1422 return -EINVAL; 1423 if (copy_from_user(&query, uquery, sizeof(query))) 1424 return -EFAULT; 1425 1426 ids_len = query.ids_len; 1427 if (ids_len > BPF_TRACE_MAX_PROGS) 1428 return -E2BIG; 1429 ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); 1430 if (!ids) 1431 return -ENOMEM; 1432 /* 1433 * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which 1434 * is required when user only wants to check for uquery->prog_cnt. 1435 * There is no need to check for it since the case is handled 1436 * gracefully in bpf_prog_array_copy_info. 1437 */ 1438 1439 mutex_lock(&bpf_event_mutex); 1440 progs = bpf_event_rcu_dereference(event->tp_event->prog_array); 1441 ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt); 1442 mutex_unlock(&bpf_event_mutex); 1443 1444 if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || 1445 copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) 1446 ret = -EFAULT; 1447 1448 kfree(ids); 1449 return ret; 1450 } 1451 1452 extern struct bpf_raw_event_map __start__bpf_raw_tp[]; 1453 extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; 1454 1455 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) 1456 { 1457 struct bpf_raw_event_map *btp = __start__bpf_raw_tp; 1458 1459 for (; btp < __stop__bpf_raw_tp; btp++) { 1460 if (!strcmp(btp->tp->name, name)) 1461 return btp; 1462 } 1463 1464 return bpf_get_raw_tracepoint_module(name); 1465 } 1466 1467 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) 1468 { 1469 struct module *mod = __module_address((unsigned long)btp); 1470 1471 if (mod) 1472 module_put(mod); 1473 } 1474 1475 static __always_inline 1476 void __bpf_trace_run(struct bpf_prog *prog, u64 *args) 1477 { 1478 rcu_read_lock(); 1479 preempt_disable(); 1480 (void) BPF_PROG_RUN(prog, args); 1481 preempt_enable(); 1482 rcu_read_unlock(); 1483 } 1484 1485 #define UNPACK(...) __VA_ARGS__ 1486 #define REPEAT_1(FN, DL, X, ...) FN(X) 1487 #define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) 1488 #define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) 1489 #define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) 1490 #define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) 1491 #define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) 1492 #define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) 1493 #define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) 1494 #define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) 1495 #define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) 1496 #define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) 1497 #define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) 1498 #define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) 1499 1500 #define SARG(X) u64 arg##X 1501 #define COPY(X) args[X] = arg##X 1502 1503 #define __DL_COM (,) 1504 #define __DL_SEM (;) 1505 1506 #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 1507 1508 #define BPF_TRACE_DEFN_x(x) \ 1509 void bpf_trace_run##x(struct bpf_prog *prog, \ 1510 REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ 1511 { \ 1512 u64 args[x]; \ 1513 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ 1514 __bpf_trace_run(prog, args); \ 1515 } \ 1516 EXPORT_SYMBOL_GPL(bpf_trace_run##x) 1517 BPF_TRACE_DEFN_x(1); 1518 BPF_TRACE_DEFN_x(2); 1519 BPF_TRACE_DEFN_x(3); 1520 BPF_TRACE_DEFN_x(4); 1521 BPF_TRACE_DEFN_x(5); 1522 BPF_TRACE_DEFN_x(6); 1523 BPF_TRACE_DEFN_x(7); 1524 BPF_TRACE_DEFN_x(8); 1525 BPF_TRACE_DEFN_x(9); 1526 BPF_TRACE_DEFN_x(10); 1527 BPF_TRACE_DEFN_x(11); 1528 BPF_TRACE_DEFN_x(12); 1529 1530 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1531 { 1532 struct tracepoint *tp = btp->tp; 1533 1534 /* 1535 * check that program doesn't access arguments beyond what's 1536 * available in this tracepoint 1537 */ 1538 if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) 1539 return -EINVAL; 1540 1541 if (prog->aux->max_tp_access > btp->writable_size) 1542 return -EINVAL; 1543 1544 return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); 1545 } 1546 1547 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1548 { 1549 return __bpf_probe_register(btp, prog); 1550 } 1551 1552 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1553 { 1554 return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); 1555 } 1556 1557 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, 1558 u32 *fd_type, const char **buf, 1559 u64 *probe_offset, u64 *probe_addr) 1560 { 1561 bool is_tracepoint, is_syscall_tp; 1562 struct bpf_prog *prog; 1563 int flags, err = 0; 1564 1565 prog = event->prog; 1566 if (!prog) 1567 return -ENOENT; 1568 1569 /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */ 1570 if (prog->type == BPF_PROG_TYPE_PERF_EVENT) 1571 return -EOPNOTSUPP; 1572 1573 *prog_id = prog->aux->id; 1574 flags = event->tp_event->flags; 1575 is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT; 1576 is_syscall_tp = is_syscall_trace_event(event->tp_event); 1577 1578 if (is_tracepoint || is_syscall_tp) { 1579 *buf = is_tracepoint ? event->tp_event->tp->name 1580 : event->tp_event->name; 1581 *fd_type = BPF_FD_TYPE_TRACEPOINT; 1582 *probe_offset = 0x0; 1583 *probe_addr = 0x0; 1584 } else { 1585 /* kprobe/uprobe */ 1586 err = -EOPNOTSUPP; 1587 #ifdef CONFIG_KPROBE_EVENTS 1588 if (flags & TRACE_EVENT_FL_KPROBE) 1589 err = bpf_get_kprobe_info(event, fd_type, buf, 1590 probe_offset, probe_addr, 1591 event->attr.type == PERF_TYPE_TRACEPOINT); 1592 #endif 1593 #ifdef CONFIG_UPROBE_EVENTS 1594 if (flags & TRACE_EVENT_FL_UPROBE) 1595 err = bpf_get_uprobe_info(event, fd_type, buf, 1596 probe_offset, 1597 event->attr.type == PERF_TYPE_TRACEPOINT); 1598 #endif 1599 } 1600 1601 return err; 1602 } 1603 1604 static int __init send_signal_irq_work_init(void) 1605 { 1606 int cpu; 1607 struct send_signal_irq_work *work; 1608 1609 for_each_possible_cpu(cpu) { 1610 work = per_cpu_ptr(&send_signal_work, cpu); 1611 init_irq_work(&work->irq_work, do_bpf_send_signal); 1612 } 1613 return 0; 1614 } 1615 1616 subsys_initcall(send_signal_irq_work_init); 1617 1618 #ifdef CONFIG_MODULES 1619 static int bpf_event_notify(struct notifier_block *nb, unsigned long op, 1620 void *module) 1621 { 1622 struct bpf_trace_module *btm, *tmp; 1623 struct module *mod = module; 1624 1625 if (mod->num_bpf_raw_events == 0 || 1626 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 1627 return 0; 1628 1629 mutex_lock(&bpf_module_mutex); 1630 1631 switch (op) { 1632 case MODULE_STATE_COMING: 1633 btm = kzalloc(sizeof(*btm), GFP_KERNEL); 1634 if (btm) { 1635 btm->module = module; 1636 list_add(&btm->list, &bpf_trace_modules); 1637 } 1638 break; 1639 case MODULE_STATE_GOING: 1640 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) { 1641 if (btm->module == module) { 1642 list_del(&btm->list); 1643 kfree(btm); 1644 break; 1645 } 1646 } 1647 break; 1648 } 1649 1650 mutex_unlock(&bpf_module_mutex); 1651 1652 return 0; 1653 } 1654 1655 static struct notifier_block bpf_module_nb = { 1656 .notifier_call = bpf_event_notify, 1657 }; 1658 1659 static int __init bpf_event_init(void) 1660 { 1661 register_module_notifier(&bpf_module_nb); 1662 return 0; 1663 } 1664 1665 fs_initcall(bpf_event_init); 1666 #endif /* CONFIG_MODULES */ 1667