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 cant_sleep(); 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); 118 119 return ret; 120 } 121 122 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 123 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) 124 { 125 regs_set_return_value(regs, rc); 126 override_function_with_return(regs); 127 return 0; 128 } 129 130 static const struct bpf_func_proto bpf_override_return_proto = { 131 .func = bpf_override_return, 132 .gpl_only = true, 133 .ret_type = RET_INTEGER, 134 .arg1_type = ARG_PTR_TO_CTX, 135 .arg2_type = ARG_ANYTHING, 136 }; 137 #endif 138 139 BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size, 140 const void __user *, unsafe_ptr) 141 { 142 int ret = probe_user_read(dst, unsafe_ptr, size); 143 144 if (unlikely(ret < 0)) 145 memset(dst, 0, size); 146 147 return ret; 148 } 149 150 static const struct bpf_func_proto bpf_probe_read_user_proto = { 151 .func = bpf_probe_read_user, 152 .gpl_only = true, 153 .ret_type = RET_INTEGER, 154 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 155 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 156 .arg3_type = ARG_ANYTHING, 157 }; 158 159 BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size, 160 const void __user *, unsafe_ptr) 161 { 162 int ret = strncpy_from_unsafe_user(dst, unsafe_ptr, size); 163 164 if (unlikely(ret < 0)) 165 memset(dst, 0, size); 166 167 return ret; 168 } 169 170 static const struct bpf_func_proto bpf_probe_read_user_str_proto = { 171 .func = bpf_probe_read_user_str, 172 .gpl_only = true, 173 .ret_type = RET_INTEGER, 174 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 175 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 176 .arg3_type = ARG_ANYTHING, 177 }; 178 179 static __always_inline int 180 bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr, 181 const bool compat) 182 { 183 int ret = security_locked_down(LOCKDOWN_BPF_READ); 184 185 if (unlikely(ret < 0)) 186 goto out; 187 ret = compat ? probe_kernel_read(dst, unsafe_ptr, size) : 188 probe_kernel_read_strict(dst, unsafe_ptr, size); 189 if (unlikely(ret < 0)) 190 out: 191 memset(dst, 0, size); 192 return ret; 193 } 194 195 BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size, 196 const void *, unsafe_ptr) 197 { 198 return bpf_probe_read_kernel_common(dst, size, unsafe_ptr, false); 199 } 200 201 static const struct bpf_func_proto bpf_probe_read_kernel_proto = { 202 .func = bpf_probe_read_kernel, 203 .gpl_only = true, 204 .ret_type = RET_INTEGER, 205 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 206 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 207 .arg3_type = ARG_ANYTHING, 208 }; 209 210 BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size, 211 const void *, unsafe_ptr) 212 { 213 return bpf_probe_read_kernel_common(dst, size, unsafe_ptr, true); 214 } 215 216 static const struct bpf_func_proto bpf_probe_read_compat_proto = { 217 .func = bpf_probe_read_compat, 218 .gpl_only = true, 219 .ret_type = RET_INTEGER, 220 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 221 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 222 .arg3_type = ARG_ANYTHING, 223 }; 224 225 static __always_inline int 226 bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr, 227 const bool compat) 228 { 229 int ret = security_locked_down(LOCKDOWN_BPF_READ); 230 231 if (unlikely(ret < 0)) 232 goto out; 233 /* 234 * The strncpy_from_unsafe_*() call will likely not fill the entire 235 * buffer, but that's okay in this circumstance as we're probing 236 * arbitrary memory anyway similar to bpf_probe_read_*() and might 237 * as well probe the stack. Thus, memory is explicitly cleared 238 * only in error case, so that improper users ignoring return 239 * code altogether don't copy garbage; otherwise length of string 240 * is returned that can be used for bpf_perf_event_output() et al. 241 */ 242 ret = compat ? strncpy_from_unsafe(dst, unsafe_ptr, size) : 243 strncpy_from_unsafe_strict(dst, unsafe_ptr, size); 244 if (unlikely(ret < 0)) 245 out: 246 memset(dst, 0, size); 247 return ret; 248 } 249 250 BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size, 251 const void *, unsafe_ptr) 252 { 253 return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr, false); 254 } 255 256 static const struct bpf_func_proto bpf_probe_read_kernel_str_proto = { 257 .func = bpf_probe_read_kernel_str, 258 .gpl_only = true, 259 .ret_type = RET_INTEGER, 260 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 261 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 262 .arg3_type = ARG_ANYTHING, 263 }; 264 265 BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size, 266 const void *, unsafe_ptr) 267 { 268 return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr, true); 269 } 270 271 static const struct bpf_func_proto bpf_probe_read_compat_str_proto = { 272 .func = bpf_probe_read_compat_str, 273 .gpl_only = true, 274 .ret_type = RET_INTEGER, 275 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 276 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 277 .arg3_type = ARG_ANYTHING, 278 }; 279 280 BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src, 281 u32, size) 282 { 283 /* 284 * Ensure we're in user context which is safe for the helper to 285 * run. This helper has no business in a kthread. 286 * 287 * access_ok() should prevent writing to non-user memory, but in 288 * some situations (nommu, temporary switch, etc) access_ok() does 289 * not provide enough validation, hence the check on KERNEL_DS. 290 * 291 * nmi_uaccess_okay() ensures the probe is not run in an interim 292 * state, when the task or mm are switched. This is specifically 293 * required to prevent the use of temporary mm. 294 */ 295 296 if (unlikely(in_interrupt() || 297 current->flags & (PF_KTHREAD | PF_EXITING))) 298 return -EPERM; 299 if (unlikely(uaccess_kernel())) 300 return -EPERM; 301 if (unlikely(!nmi_uaccess_okay())) 302 return -EPERM; 303 304 return probe_user_write(unsafe_ptr, src, size); 305 } 306 307 static const struct bpf_func_proto bpf_probe_write_user_proto = { 308 .func = bpf_probe_write_user, 309 .gpl_only = true, 310 .ret_type = RET_INTEGER, 311 .arg1_type = ARG_ANYTHING, 312 .arg2_type = ARG_PTR_TO_MEM, 313 .arg3_type = ARG_CONST_SIZE, 314 }; 315 316 static const struct bpf_func_proto *bpf_get_probe_write_proto(void) 317 { 318 pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", 319 current->comm, task_pid_nr(current)); 320 321 return &bpf_probe_write_user_proto; 322 } 323 324 /* 325 * Only limited trace_printk() conversion specifiers allowed: 326 * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pks %pus %s 327 */ 328 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, 329 u64, arg2, u64, arg3) 330 { 331 int i, mod[3] = {}, fmt_cnt = 0; 332 char buf[64], fmt_ptype; 333 void *unsafe_ptr = NULL; 334 bool str_seen = false; 335 336 /* 337 * bpf_check()->check_func_arg()->check_stack_boundary() 338 * guarantees that fmt points to bpf program stack, 339 * fmt_size bytes of it were initialized and fmt_size > 0 340 */ 341 if (fmt[--fmt_size] != 0) 342 return -EINVAL; 343 344 /* check format string for allowed specifiers */ 345 for (i = 0; i < fmt_size; i++) { 346 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) 347 return -EINVAL; 348 349 if (fmt[i] != '%') 350 continue; 351 352 if (fmt_cnt >= 3) 353 return -EINVAL; 354 355 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ 356 i++; 357 if (fmt[i] == 'l') { 358 mod[fmt_cnt]++; 359 i++; 360 } else if (fmt[i] == 'p') { 361 mod[fmt_cnt]++; 362 if ((fmt[i + 1] == 'k' || 363 fmt[i + 1] == 'u') && 364 fmt[i + 2] == 's') { 365 fmt_ptype = fmt[i + 1]; 366 i += 2; 367 goto fmt_str; 368 } 369 370 /* disallow any further format extensions */ 371 if (fmt[i + 1] != 0 && 372 !isspace(fmt[i + 1]) && 373 !ispunct(fmt[i + 1])) 374 return -EINVAL; 375 376 goto fmt_next; 377 } else if (fmt[i] == 's') { 378 mod[fmt_cnt]++; 379 fmt_ptype = fmt[i]; 380 fmt_str: 381 if (str_seen) 382 /* allow only one '%s' per fmt string */ 383 return -EINVAL; 384 str_seen = true; 385 386 if (fmt[i + 1] != 0 && 387 !isspace(fmt[i + 1]) && 388 !ispunct(fmt[i + 1])) 389 return -EINVAL; 390 391 switch (fmt_cnt) { 392 case 0: 393 unsafe_ptr = (void *)(long)arg1; 394 arg1 = (long)buf; 395 break; 396 case 1: 397 unsafe_ptr = (void *)(long)arg2; 398 arg2 = (long)buf; 399 break; 400 case 2: 401 unsafe_ptr = (void *)(long)arg3; 402 arg3 = (long)buf; 403 break; 404 } 405 406 buf[0] = 0; 407 switch (fmt_ptype) { 408 case 's': 409 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 410 strncpy_from_unsafe(buf, unsafe_ptr, 411 sizeof(buf)); 412 break; 413 #endif 414 case 'k': 415 strncpy_from_unsafe_strict(buf, unsafe_ptr, 416 sizeof(buf)); 417 break; 418 case 'u': 419 strncpy_from_unsafe_user(buf, 420 (__force void __user *)unsafe_ptr, 421 sizeof(buf)); 422 break; 423 } 424 goto fmt_next; 425 } 426 427 if (fmt[i] == 'l') { 428 mod[fmt_cnt]++; 429 i++; 430 } 431 432 if (fmt[i] != 'i' && fmt[i] != 'd' && 433 fmt[i] != 'u' && fmt[i] != 'x') 434 return -EINVAL; 435 fmt_next: 436 fmt_cnt++; 437 } 438 439 /* Horrid workaround for getting va_list handling working with different 440 * argument type combinations generically for 32 and 64 bit archs. 441 */ 442 #define __BPF_TP_EMIT() __BPF_ARG3_TP() 443 #define __BPF_TP(...) \ 444 __trace_printk(0 /* Fake ip */, \ 445 fmt, ##__VA_ARGS__) 446 447 #define __BPF_ARG1_TP(...) \ 448 ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ 449 ? __BPF_TP(arg1, ##__VA_ARGS__) \ 450 : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ 451 ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ 452 : __BPF_TP((u32)arg1, ##__VA_ARGS__))) 453 454 #define __BPF_ARG2_TP(...) \ 455 ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ 456 ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ 457 : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ 458 ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ 459 : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) 460 461 #define __BPF_ARG3_TP(...) \ 462 ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ 463 ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ 464 : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ 465 ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ 466 : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) 467 468 return __BPF_TP_EMIT(); 469 } 470 471 static const struct bpf_func_proto bpf_trace_printk_proto = { 472 .func = bpf_trace_printk, 473 .gpl_only = true, 474 .ret_type = RET_INTEGER, 475 .arg1_type = ARG_PTR_TO_MEM, 476 .arg2_type = ARG_CONST_SIZE, 477 }; 478 479 const struct bpf_func_proto *bpf_get_trace_printk_proto(void) 480 { 481 /* 482 * this program might be calling bpf_trace_printk, 483 * so allocate per-cpu printk buffers 484 */ 485 trace_printk_init_buffers(); 486 487 return &bpf_trace_printk_proto; 488 } 489 490 static __always_inline int 491 get_map_perf_counter(struct bpf_map *map, u64 flags, 492 u64 *value, u64 *enabled, u64 *running) 493 { 494 struct bpf_array *array = container_of(map, struct bpf_array, map); 495 unsigned int cpu = smp_processor_id(); 496 u64 index = flags & BPF_F_INDEX_MASK; 497 struct bpf_event_entry *ee; 498 499 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) 500 return -EINVAL; 501 if (index == BPF_F_CURRENT_CPU) 502 index = cpu; 503 if (unlikely(index >= array->map.max_entries)) 504 return -E2BIG; 505 506 ee = READ_ONCE(array->ptrs[index]); 507 if (!ee) 508 return -ENOENT; 509 510 return perf_event_read_local(ee->event, value, enabled, running); 511 } 512 513 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) 514 { 515 u64 value = 0; 516 int err; 517 518 err = get_map_perf_counter(map, flags, &value, NULL, NULL); 519 /* 520 * this api is ugly since we miss [-22..-2] range of valid 521 * counter values, but that's uapi 522 */ 523 if (err) 524 return err; 525 return value; 526 } 527 528 static const struct bpf_func_proto bpf_perf_event_read_proto = { 529 .func = bpf_perf_event_read, 530 .gpl_only = true, 531 .ret_type = RET_INTEGER, 532 .arg1_type = ARG_CONST_MAP_PTR, 533 .arg2_type = ARG_ANYTHING, 534 }; 535 536 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags, 537 struct bpf_perf_event_value *, buf, u32, size) 538 { 539 int err = -EINVAL; 540 541 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 542 goto clear; 543 err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled, 544 &buf->running); 545 if (unlikely(err)) 546 goto clear; 547 return 0; 548 clear: 549 memset(buf, 0, size); 550 return err; 551 } 552 553 static const struct bpf_func_proto bpf_perf_event_read_value_proto = { 554 .func = bpf_perf_event_read_value, 555 .gpl_only = true, 556 .ret_type = RET_INTEGER, 557 .arg1_type = ARG_CONST_MAP_PTR, 558 .arg2_type = ARG_ANYTHING, 559 .arg3_type = ARG_PTR_TO_UNINIT_MEM, 560 .arg4_type = ARG_CONST_SIZE, 561 }; 562 563 static __always_inline u64 564 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, 565 u64 flags, struct perf_sample_data *sd) 566 { 567 struct bpf_array *array = container_of(map, struct bpf_array, map); 568 unsigned int cpu = smp_processor_id(); 569 u64 index = flags & BPF_F_INDEX_MASK; 570 struct bpf_event_entry *ee; 571 struct perf_event *event; 572 573 if (index == BPF_F_CURRENT_CPU) 574 index = cpu; 575 if (unlikely(index >= array->map.max_entries)) 576 return -E2BIG; 577 578 ee = READ_ONCE(array->ptrs[index]); 579 if (!ee) 580 return -ENOENT; 581 582 event = ee->event; 583 if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || 584 event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) 585 return -EINVAL; 586 587 if (unlikely(event->oncpu != cpu)) 588 return -EOPNOTSUPP; 589 590 return perf_event_output(event, sd, regs); 591 } 592 593 /* 594 * Support executing tracepoints in normal, irq, and nmi context that each call 595 * bpf_perf_event_output 596 */ 597 struct bpf_trace_sample_data { 598 struct perf_sample_data sds[3]; 599 }; 600 601 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); 602 static DEFINE_PER_CPU(int, bpf_trace_nest_level); 603 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, 604 u64, flags, void *, data, u64, size) 605 { 606 struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds); 607 int nest_level = this_cpu_inc_return(bpf_trace_nest_level); 608 struct perf_raw_record raw = { 609 .frag = { 610 .size = size, 611 .data = data, 612 }, 613 }; 614 struct perf_sample_data *sd; 615 int err; 616 617 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { 618 err = -EBUSY; 619 goto out; 620 } 621 622 sd = &sds->sds[nest_level - 1]; 623 624 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { 625 err = -EINVAL; 626 goto out; 627 } 628 629 perf_sample_data_init(sd, 0, 0); 630 sd->raw = &raw; 631 632 err = __bpf_perf_event_output(regs, map, flags, sd); 633 634 out: 635 this_cpu_dec(bpf_trace_nest_level); 636 return err; 637 } 638 639 static const struct bpf_func_proto bpf_perf_event_output_proto = { 640 .func = bpf_perf_event_output, 641 .gpl_only = true, 642 .ret_type = RET_INTEGER, 643 .arg1_type = ARG_PTR_TO_CTX, 644 .arg2_type = ARG_CONST_MAP_PTR, 645 .arg3_type = ARG_ANYTHING, 646 .arg4_type = ARG_PTR_TO_MEM, 647 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 648 }; 649 650 static DEFINE_PER_CPU(int, bpf_event_output_nest_level); 651 struct bpf_nested_pt_regs { 652 struct pt_regs regs[3]; 653 }; 654 static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs); 655 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds); 656 657 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 658 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 659 { 660 int nest_level = this_cpu_inc_return(bpf_event_output_nest_level); 661 struct perf_raw_frag frag = { 662 .copy = ctx_copy, 663 .size = ctx_size, 664 .data = ctx, 665 }; 666 struct perf_raw_record raw = { 667 .frag = { 668 { 669 .next = ctx_size ? &frag : NULL, 670 }, 671 .size = meta_size, 672 .data = meta, 673 }, 674 }; 675 struct perf_sample_data *sd; 676 struct pt_regs *regs; 677 u64 ret; 678 679 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) { 680 ret = -EBUSY; 681 goto out; 682 } 683 sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]); 684 regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]); 685 686 perf_fetch_caller_regs(regs); 687 perf_sample_data_init(sd, 0, 0); 688 sd->raw = &raw; 689 690 ret = __bpf_perf_event_output(regs, map, flags, sd); 691 out: 692 this_cpu_dec(bpf_event_output_nest_level); 693 return ret; 694 } 695 696 BPF_CALL_0(bpf_get_current_task) 697 { 698 return (long) current; 699 } 700 701 static const struct bpf_func_proto bpf_get_current_task_proto = { 702 .func = bpf_get_current_task, 703 .gpl_only = true, 704 .ret_type = RET_INTEGER, 705 }; 706 707 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) 708 { 709 struct bpf_array *array = container_of(map, struct bpf_array, map); 710 struct cgroup *cgrp; 711 712 if (unlikely(idx >= array->map.max_entries)) 713 return -E2BIG; 714 715 cgrp = READ_ONCE(array->ptrs[idx]); 716 if (unlikely(!cgrp)) 717 return -EAGAIN; 718 719 return task_under_cgroup_hierarchy(current, cgrp); 720 } 721 722 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { 723 .func = bpf_current_task_under_cgroup, 724 .gpl_only = false, 725 .ret_type = RET_INTEGER, 726 .arg1_type = ARG_CONST_MAP_PTR, 727 .arg2_type = ARG_ANYTHING, 728 }; 729 730 struct send_signal_irq_work { 731 struct irq_work irq_work; 732 struct task_struct *task; 733 u32 sig; 734 enum pid_type type; 735 }; 736 737 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); 738 739 static void do_bpf_send_signal(struct irq_work *entry) 740 { 741 struct send_signal_irq_work *work; 742 743 work = container_of(entry, struct send_signal_irq_work, irq_work); 744 group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type); 745 } 746 747 static int bpf_send_signal_common(u32 sig, enum pid_type type) 748 { 749 struct send_signal_irq_work *work = NULL; 750 751 /* Similar to bpf_probe_write_user, task needs to be 752 * in a sound condition and kernel memory access be 753 * permitted in order to send signal to the current 754 * task. 755 */ 756 if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) 757 return -EPERM; 758 if (unlikely(uaccess_kernel())) 759 return -EPERM; 760 if (unlikely(!nmi_uaccess_okay())) 761 return -EPERM; 762 763 if (irqs_disabled()) { 764 /* Do an early check on signal validity. Otherwise, 765 * the error is lost in deferred irq_work. 766 */ 767 if (unlikely(!valid_signal(sig))) 768 return -EINVAL; 769 770 work = this_cpu_ptr(&send_signal_work); 771 if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY) 772 return -EBUSY; 773 774 /* Add the current task, which is the target of sending signal, 775 * to the irq_work. The current task may change when queued 776 * irq works get executed. 777 */ 778 work->task = current; 779 work->sig = sig; 780 work->type = type; 781 irq_work_queue(&work->irq_work); 782 return 0; 783 } 784 785 return group_send_sig_info(sig, SEND_SIG_PRIV, current, type); 786 } 787 788 BPF_CALL_1(bpf_send_signal, u32, sig) 789 { 790 return bpf_send_signal_common(sig, PIDTYPE_TGID); 791 } 792 793 static const struct bpf_func_proto bpf_send_signal_proto = { 794 .func = bpf_send_signal, 795 .gpl_only = false, 796 .ret_type = RET_INTEGER, 797 .arg1_type = ARG_ANYTHING, 798 }; 799 800 BPF_CALL_1(bpf_send_signal_thread, u32, sig) 801 { 802 return bpf_send_signal_common(sig, PIDTYPE_PID); 803 } 804 805 static const struct bpf_func_proto bpf_send_signal_thread_proto = { 806 .func = bpf_send_signal_thread, 807 .gpl_only = false, 808 .ret_type = RET_INTEGER, 809 .arg1_type = ARG_ANYTHING, 810 }; 811 812 const struct bpf_func_proto * 813 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 814 { 815 switch (func_id) { 816 case BPF_FUNC_map_lookup_elem: 817 return &bpf_map_lookup_elem_proto; 818 case BPF_FUNC_map_update_elem: 819 return &bpf_map_update_elem_proto; 820 case BPF_FUNC_map_delete_elem: 821 return &bpf_map_delete_elem_proto; 822 case BPF_FUNC_map_push_elem: 823 return &bpf_map_push_elem_proto; 824 case BPF_FUNC_map_pop_elem: 825 return &bpf_map_pop_elem_proto; 826 case BPF_FUNC_map_peek_elem: 827 return &bpf_map_peek_elem_proto; 828 case BPF_FUNC_ktime_get_ns: 829 return &bpf_ktime_get_ns_proto; 830 case BPF_FUNC_tail_call: 831 return &bpf_tail_call_proto; 832 case BPF_FUNC_get_current_pid_tgid: 833 return &bpf_get_current_pid_tgid_proto; 834 case BPF_FUNC_get_current_task: 835 return &bpf_get_current_task_proto; 836 case BPF_FUNC_get_current_uid_gid: 837 return &bpf_get_current_uid_gid_proto; 838 case BPF_FUNC_get_current_comm: 839 return &bpf_get_current_comm_proto; 840 case BPF_FUNC_trace_printk: 841 return bpf_get_trace_printk_proto(); 842 case BPF_FUNC_get_smp_processor_id: 843 return &bpf_get_smp_processor_id_proto; 844 case BPF_FUNC_get_numa_node_id: 845 return &bpf_get_numa_node_id_proto; 846 case BPF_FUNC_perf_event_read: 847 return &bpf_perf_event_read_proto; 848 case BPF_FUNC_probe_write_user: 849 return bpf_get_probe_write_proto(); 850 case BPF_FUNC_current_task_under_cgroup: 851 return &bpf_current_task_under_cgroup_proto; 852 case BPF_FUNC_get_prandom_u32: 853 return &bpf_get_prandom_u32_proto; 854 case BPF_FUNC_probe_read_user: 855 return &bpf_probe_read_user_proto; 856 case BPF_FUNC_probe_read_kernel: 857 return &bpf_probe_read_kernel_proto; 858 case BPF_FUNC_probe_read_user_str: 859 return &bpf_probe_read_user_str_proto; 860 case BPF_FUNC_probe_read_kernel_str: 861 return &bpf_probe_read_kernel_str_proto; 862 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 863 case BPF_FUNC_probe_read: 864 return &bpf_probe_read_compat_proto; 865 case BPF_FUNC_probe_read_str: 866 return &bpf_probe_read_compat_str_proto; 867 #endif 868 #ifdef CONFIG_CGROUPS 869 case BPF_FUNC_get_current_cgroup_id: 870 return &bpf_get_current_cgroup_id_proto; 871 #endif 872 case BPF_FUNC_send_signal: 873 return &bpf_send_signal_proto; 874 case BPF_FUNC_send_signal_thread: 875 return &bpf_send_signal_thread_proto; 876 case BPF_FUNC_perf_event_read_value: 877 return &bpf_perf_event_read_value_proto; 878 case BPF_FUNC_get_ns_current_pid_tgid: 879 return &bpf_get_ns_current_pid_tgid_proto; 880 default: 881 return NULL; 882 } 883 } 884 885 static const struct bpf_func_proto * 886 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 887 { 888 switch (func_id) { 889 case BPF_FUNC_perf_event_output: 890 return &bpf_perf_event_output_proto; 891 case BPF_FUNC_get_stackid: 892 return &bpf_get_stackid_proto; 893 case BPF_FUNC_get_stack: 894 return &bpf_get_stack_proto; 895 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 896 case BPF_FUNC_override_return: 897 return &bpf_override_return_proto; 898 #endif 899 default: 900 return bpf_tracing_func_proto(func_id, prog); 901 } 902 } 903 904 /* bpf+kprobe programs can access fields of 'struct pt_regs' */ 905 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 906 const struct bpf_prog *prog, 907 struct bpf_insn_access_aux *info) 908 { 909 if (off < 0 || off >= sizeof(struct pt_regs)) 910 return false; 911 if (type != BPF_READ) 912 return false; 913 if (off % size != 0) 914 return false; 915 /* 916 * Assertion for 32 bit to make sure last 8 byte access 917 * (BPF_DW) to the last 4 byte member is disallowed. 918 */ 919 if (off + size > sizeof(struct pt_regs)) 920 return false; 921 922 return true; 923 } 924 925 const struct bpf_verifier_ops kprobe_verifier_ops = { 926 .get_func_proto = kprobe_prog_func_proto, 927 .is_valid_access = kprobe_prog_is_valid_access, 928 }; 929 930 const struct bpf_prog_ops kprobe_prog_ops = { 931 }; 932 933 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, 934 u64, flags, void *, data, u64, size) 935 { 936 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 937 938 /* 939 * r1 points to perf tracepoint buffer where first 8 bytes are hidden 940 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it 941 * from there and call the same bpf_perf_event_output() helper inline. 942 */ 943 return ____bpf_perf_event_output(regs, map, flags, data, size); 944 } 945 946 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { 947 .func = bpf_perf_event_output_tp, 948 .gpl_only = true, 949 .ret_type = RET_INTEGER, 950 .arg1_type = ARG_PTR_TO_CTX, 951 .arg2_type = ARG_CONST_MAP_PTR, 952 .arg3_type = ARG_ANYTHING, 953 .arg4_type = ARG_PTR_TO_MEM, 954 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 955 }; 956 957 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, 958 u64, flags) 959 { 960 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 961 962 /* 963 * Same comment as in bpf_perf_event_output_tp(), only that this time 964 * the other helper's function body cannot be inlined due to being 965 * external, thus we need to call raw helper function. 966 */ 967 return bpf_get_stackid((unsigned long) regs, (unsigned long) map, 968 flags, 0, 0); 969 } 970 971 static const struct bpf_func_proto bpf_get_stackid_proto_tp = { 972 .func = bpf_get_stackid_tp, 973 .gpl_only = true, 974 .ret_type = RET_INTEGER, 975 .arg1_type = ARG_PTR_TO_CTX, 976 .arg2_type = ARG_CONST_MAP_PTR, 977 .arg3_type = ARG_ANYTHING, 978 }; 979 980 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size, 981 u64, flags) 982 { 983 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 984 985 return bpf_get_stack((unsigned long) regs, (unsigned long) buf, 986 (unsigned long) size, flags, 0); 987 } 988 989 static const struct bpf_func_proto bpf_get_stack_proto_tp = { 990 .func = bpf_get_stack_tp, 991 .gpl_only = true, 992 .ret_type = RET_INTEGER, 993 .arg1_type = ARG_PTR_TO_CTX, 994 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 995 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 996 .arg4_type = ARG_ANYTHING, 997 }; 998 999 static const struct bpf_func_proto * 1000 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1001 { 1002 switch (func_id) { 1003 case BPF_FUNC_perf_event_output: 1004 return &bpf_perf_event_output_proto_tp; 1005 case BPF_FUNC_get_stackid: 1006 return &bpf_get_stackid_proto_tp; 1007 case BPF_FUNC_get_stack: 1008 return &bpf_get_stack_proto_tp; 1009 default: 1010 return bpf_tracing_func_proto(func_id, prog); 1011 } 1012 } 1013 1014 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1015 const struct bpf_prog *prog, 1016 struct bpf_insn_access_aux *info) 1017 { 1018 if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) 1019 return false; 1020 if (type != BPF_READ) 1021 return false; 1022 if (off % size != 0) 1023 return false; 1024 1025 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); 1026 return true; 1027 } 1028 1029 const struct bpf_verifier_ops tracepoint_verifier_ops = { 1030 .get_func_proto = tp_prog_func_proto, 1031 .is_valid_access = tp_prog_is_valid_access, 1032 }; 1033 1034 const struct bpf_prog_ops tracepoint_prog_ops = { 1035 }; 1036 1037 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx, 1038 struct bpf_perf_event_value *, buf, u32, size) 1039 { 1040 int err = -EINVAL; 1041 1042 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 1043 goto clear; 1044 err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, 1045 &buf->running); 1046 if (unlikely(err)) 1047 goto clear; 1048 return 0; 1049 clear: 1050 memset(buf, 0, size); 1051 return err; 1052 } 1053 1054 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { 1055 .func = bpf_perf_prog_read_value, 1056 .gpl_only = true, 1057 .ret_type = RET_INTEGER, 1058 .arg1_type = ARG_PTR_TO_CTX, 1059 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 1060 .arg3_type = ARG_CONST_SIZE, 1061 }; 1062 1063 BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx, 1064 void *, buf, u32, size, u64, flags) 1065 { 1066 #ifndef CONFIG_X86 1067 return -ENOENT; 1068 #else 1069 static const u32 br_entry_size = sizeof(struct perf_branch_entry); 1070 struct perf_branch_stack *br_stack = ctx->data->br_stack; 1071 u32 to_copy; 1072 1073 if (unlikely(flags & ~BPF_F_GET_BRANCH_RECORDS_SIZE)) 1074 return -EINVAL; 1075 1076 if (unlikely(!br_stack)) 1077 return -EINVAL; 1078 1079 if (flags & BPF_F_GET_BRANCH_RECORDS_SIZE) 1080 return br_stack->nr * br_entry_size; 1081 1082 if (!buf || (size % br_entry_size != 0)) 1083 return -EINVAL; 1084 1085 to_copy = min_t(u32, br_stack->nr * br_entry_size, size); 1086 memcpy(buf, br_stack->entries, to_copy); 1087 1088 return to_copy; 1089 #endif 1090 } 1091 1092 static const struct bpf_func_proto bpf_read_branch_records_proto = { 1093 .func = bpf_read_branch_records, 1094 .gpl_only = true, 1095 .ret_type = RET_INTEGER, 1096 .arg1_type = ARG_PTR_TO_CTX, 1097 .arg2_type = ARG_PTR_TO_MEM_OR_NULL, 1098 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1099 .arg4_type = ARG_ANYTHING, 1100 }; 1101 1102 static const struct bpf_func_proto * 1103 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1104 { 1105 switch (func_id) { 1106 case BPF_FUNC_perf_event_output: 1107 return &bpf_perf_event_output_proto_tp; 1108 case BPF_FUNC_get_stackid: 1109 return &bpf_get_stackid_proto_tp; 1110 case BPF_FUNC_get_stack: 1111 return &bpf_get_stack_proto_tp; 1112 case BPF_FUNC_perf_prog_read_value: 1113 return &bpf_perf_prog_read_value_proto; 1114 case BPF_FUNC_read_branch_records: 1115 return &bpf_read_branch_records_proto; 1116 default: 1117 return bpf_tracing_func_proto(func_id, prog); 1118 } 1119 } 1120 1121 /* 1122 * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp 1123 * to avoid potential recursive reuse issue when/if tracepoints are added 1124 * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. 1125 * 1126 * Since raw tracepoints run despite bpf_prog_active, support concurrent usage 1127 * in normal, irq, and nmi context. 1128 */ 1129 struct bpf_raw_tp_regs { 1130 struct pt_regs regs[3]; 1131 }; 1132 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); 1133 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); 1134 static struct pt_regs *get_bpf_raw_tp_regs(void) 1135 { 1136 struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); 1137 int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); 1138 1139 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { 1140 this_cpu_dec(bpf_raw_tp_nest_level); 1141 return ERR_PTR(-EBUSY); 1142 } 1143 1144 return &tp_regs->regs[nest_level - 1]; 1145 } 1146 1147 static void put_bpf_raw_tp_regs(void) 1148 { 1149 this_cpu_dec(bpf_raw_tp_nest_level); 1150 } 1151 1152 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, 1153 struct bpf_map *, map, u64, flags, void *, data, u64, size) 1154 { 1155 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1156 int ret; 1157 1158 if (IS_ERR(regs)) 1159 return PTR_ERR(regs); 1160 1161 perf_fetch_caller_regs(regs); 1162 ret = ____bpf_perf_event_output(regs, map, flags, data, size); 1163 1164 put_bpf_raw_tp_regs(); 1165 return ret; 1166 } 1167 1168 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { 1169 .func = bpf_perf_event_output_raw_tp, 1170 .gpl_only = true, 1171 .ret_type = RET_INTEGER, 1172 .arg1_type = ARG_PTR_TO_CTX, 1173 .arg2_type = ARG_CONST_MAP_PTR, 1174 .arg3_type = ARG_ANYTHING, 1175 .arg4_type = ARG_PTR_TO_MEM, 1176 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 1177 }; 1178 1179 extern const struct bpf_func_proto bpf_skb_output_proto; 1180 extern const struct bpf_func_proto bpf_xdp_output_proto; 1181 1182 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, 1183 struct bpf_map *, map, u64, flags) 1184 { 1185 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1186 int ret; 1187 1188 if (IS_ERR(regs)) 1189 return PTR_ERR(regs); 1190 1191 perf_fetch_caller_regs(regs); 1192 /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ 1193 ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, 1194 flags, 0, 0); 1195 put_bpf_raw_tp_regs(); 1196 return ret; 1197 } 1198 1199 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { 1200 .func = bpf_get_stackid_raw_tp, 1201 .gpl_only = true, 1202 .ret_type = RET_INTEGER, 1203 .arg1_type = ARG_PTR_TO_CTX, 1204 .arg2_type = ARG_CONST_MAP_PTR, 1205 .arg3_type = ARG_ANYTHING, 1206 }; 1207 1208 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, 1209 void *, buf, u32, size, u64, flags) 1210 { 1211 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1212 int ret; 1213 1214 if (IS_ERR(regs)) 1215 return PTR_ERR(regs); 1216 1217 perf_fetch_caller_regs(regs); 1218 ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, 1219 (unsigned long) size, flags, 0); 1220 put_bpf_raw_tp_regs(); 1221 return ret; 1222 } 1223 1224 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { 1225 .func = bpf_get_stack_raw_tp, 1226 .gpl_only = true, 1227 .ret_type = RET_INTEGER, 1228 .arg1_type = ARG_PTR_TO_CTX, 1229 .arg2_type = ARG_PTR_TO_MEM, 1230 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1231 .arg4_type = ARG_ANYTHING, 1232 }; 1233 1234 static const struct bpf_func_proto * 1235 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1236 { 1237 switch (func_id) { 1238 case BPF_FUNC_perf_event_output: 1239 return &bpf_perf_event_output_proto_raw_tp; 1240 case BPF_FUNC_get_stackid: 1241 return &bpf_get_stackid_proto_raw_tp; 1242 case BPF_FUNC_get_stack: 1243 return &bpf_get_stack_proto_raw_tp; 1244 default: 1245 return bpf_tracing_func_proto(func_id, prog); 1246 } 1247 } 1248 1249 static const struct bpf_func_proto * 1250 tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1251 { 1252 switch (func_id) { 1253 #ifdef CONFIG_NET 1254 case BPF_FUNC_skb_output: 1255 return &bpf_skb_output_proto; 1256 case BPF_FUNC_xdp_output: 1257 return &bpf_xdp_output_proto; 1258 #endif 1259 default: 1260 return raw_tp_prog_func_proto(func_id, prog); 1261 } 1262 } 1263 1264 static bool raw_tp_prog_is_valid_access(int off, int size, 1265 enum bpf_access_type type, 1266 const struct bpf_prog *prog, 1267 struct bpf_insn_access_aux *info) 1268 { 1269 if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) 1270 return false; 1271 if (type != BPF_READ) 1272 return false; 1273 if (off % size != 0) 1274 return false; 1275 return true; 1276 } 1277 1278 static bool tracing_prog_is_valid_access(int off, int size, 1279 enum bpf_access_type type, 1280 const struct bpf_prog *prog, 1281 struct bpf_insn_access_aux *info) 1282 { 1283 if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) 1284 return false; 1285 if (type != BPF_READ) 1286 return false; 1287 if (off % size != 0) 1288 return false; 1289 return btf_ctx_access(off, size, type, prog, info); 1290 } 1291 1292 int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog, 1293 const union bpf_attr *kattr, 1294 union bpf_attr __user *uattr) 1295 { 1296 return -ENOTSUPP; 1297 } 1298 1299 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { 1300 .get_func_proto = raw_tp_prog_func_proto, 1301 .is_valid_access = raw_tp_prog_is_valid_access, 1302 }; 1303 1304 const struct bpf_prog_ops raw_tracepoint_prog_ops = { 1305 }; 1306 1307 const struct bpf_verifier_ops tracing_verifier_ops = { 1308 .get_func_proto = tracing_prog_func_proto, 1309 .is_valid_access = tracing_prog_is_valid_access, 1310 }; 1311 1312 const struct bpf_prog_ops tracing_prog_ops = { 1313 .test_run = bpf_prog_test_run_tracing, 1314 }; 1315 1316 static bool raw_tp_writable_prog_is_valid_access(int off, int size, 1317 enum bpf_access_type type, 1318 const struct bpf_prog *prog, 1319 struct bpf_insn_access_aux *info) 1320 { 1321 if (off == 0) { 1322 if (size != sizeof(u64) || type != BPF_READ) 1323 return false; 1324 info->reg_type = PTR_TO_TP_BUFFER; 1325 } 1326 return raw_tp_prog_is_valid_access(off, size, type, prog, info); 1327 } 1328 1329 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { 1330 .get_func_proto = raw_tp_prog_func_proto, 1331 .is_valid_access = raw_tp_writable_prog_is_valid_access, 1332 }; 1333 1334 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { 1335 }; 1336 1337 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1338 const struct bpf_prog *prog, 1339 struct bpf_insn_access_aux *info) 1340 { 1341 const int size_u64 = sizeof(u64); 1342 1343 if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) 1344 return false; 1345 if (type != BPF_READ) 1346 return false; 1347 if (off % size != 0) { 1348 if (sizeof(unsigned long) != 4) 1349 return false; 1350 if (size != 8) 1351 return false; 1352 if (off % size != 4) 1353 return false; 1354 } 1355 1356 switch (off) { 1357 case bpf_ctx_range(struct bpf_perf_event_data, sample_period): 1358 bpf_ctx_record_field_size(info, size_u64); 1359 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1360 return false; 1361 break; 1362 case bpf_ctx_range(struct bpf_perf_event_data, addr): 1363 bpf_ctx_record_field_size(info, size_u64); 1364 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1365 return false; 1366 break; 1367 default: 1368 if (size != sizeof(long)) 1369 return false; 1370 } 1371 1372 return true; 1373 } 1374 1375 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, 1376 const struct bpf_insn *si, 1377 struct bpf_insn *insn_buf, 1378 struct bpf_prog *prog, u32 *target_size) 1379 { 1380 struct bpf_insn *insn = insn_buf; 1381 1382 switch (si->off) { 1383 case offsetof(struct bpf_perf_event_data, sample_period): 1384 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1385 data), si->dst_reg, si->src_reg, 1386 offsetof(struct bpf_perf_event_data_kern, data)); 1387 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1388 bpf_target_off(struct perf_sample_data, period, 8, 1389 target_size)); 1390 break; 1391 case offsetof(struct bpf_perf_event_data, addr): 1392 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1393 data), si->dst_reg, si->src_reg, 1394 offsetof(struct bpf_perf_event_data_kern, data)); 1395 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1396 bpf_target_off(struct perf_sample_data, addr, 8, 1397 target_size)); 1398 break; 1399 default: 1400 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1401 regs), si->dst_reg, si->src_reg, 1402 offsetof(struct bpf_perf_event_data_kern, regs)); 1403 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, 1404 si->off); 1405 break; 1406 } 1407 1408 return insn - insn_buf; 1409 } 1410 1411 const struct bpf_verifier_ops perf_event_verifier_ops = { 1412 .get_func_proto = pe_prog_func_proto, 1413 .is_valid_access = pe_prog_is_valid_access, 1414 .convert_ctx_access = pe_prog_convert_ctx_access, 1415 }; 1416 1417 const struct bpf_prog_ops perf_event_prog_ops = { 1418 }; 1419 1420 static DEFINE_MUTEX(bpf_event_mutex); 1421 1422 #define BPF_TRACE_MAX_PROGS 64 1423 1424 int perf_event_attach_bpf_prog(struct perf_event *event, 1425 struct bpf_prog *prog) 1426 { 1427 struct bpf_prog_array *old_array; 1428 struct bpf_prog_array *new_array; 1429 int ret = -EEXIST; 1430 1431 /* 1432 * Kprobe override only works if they are on the function entry, 1433 * and only if they are on the opt-in list. 1434 */ 1435 if (prog->kprobe_override && 1436 (!trace_kprobe_on_func_entry(event->tp_event) || 1437 !trace_kprobe_error_injectable(event->tp_event))) 1438 return -EINVAL; 1439 1440 mutex_lock(&bpf_event_mutex); 1441 1442 if (event->prog) 1443 goto unlock; 1444 1445 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1446 if (old_array && 1447 bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { 1448 ret = -E2BIG; 1449 goto unlock; 1450 } 1451 1452 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); 1453 if (ret < 0) 1454 goto unlock; 1455 1456 /* set the new array to event->tp_event and set event->prog */ 1457 event->prog = prog; 1458 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1459 bpf_prog_array_free(old_array); 1460 1461 unlock: 1462 mutex_unlock(&bpf_event_mutex); 1463 return ret; 1464 } 1465 1466 void perf_event_detach_bpf_prog(struct perf_event *event) 1467 { 1468 struct bpf_prog_array *old_array; 1469 struct bpf_prog_array *new_array; 1470 int ret; 1471 1472 mutex_lock(&bpf_event_mutex); 1473 1474 if (!event->prog) 1475 goto unlock; 1476 1477 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1478 ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); 1479 if (ret == -ENOENT) 1480 goto unlock; 1481 if (ret < 0) { 1482 bpf_prog_array_delete_safe(old_array, event->prog); 1483 } else { 1484 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1485 bpf_prog_array_free(old_array); 1486 } 1487 1488 bpf_prog_put(event->prog); 1489 event->prog = NULL; 1490 1491 unlock: 1492 mutex_unlock(&bpf_event_mutex); 1493 } 1494 1495 int perf_event_query_prog_array(struct perf_event *event, void __user *info) 1496 { 1497 struct perf_event_query_bpf __user *uquery = info; 1498 struct perf_event_query_bpf query = {}; 1499 struct bpf_prog_array *progs; 1500 u32 *ids, prog_cnt, ids_len; 1501 int ret; 1502 1503 if (!capable(CAP_SYS_ADMIN)) 1504 return -EPERM; 1505 if (event->attr.type != PERF_TYPE_TRACEPOINT) 1506 return -EINVAL; 1507 if (copy_from_user(&query, uquery, sizeof(query))) 1508 return -EFAULT; 1509 1510 ids_len = query.ids_len; 1511 if (ids_len > BPF_TRACE_MAX_PROGS) 1512 return -E2BIG; 1513 ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); 1514 if (!ids) 1515 return -ENOMEM; 1516 /* 1517 * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which 1518 * is required when user only wants to check for uquery->prog_cnt. 1519 * There is no need to check for it since the case is handled 1520 * gracefully in bpf_prog_array_copy_info. 1521 */ 1522 1523 mutex_lock(&bpf_event_mutex); 1524 progs = bpf_event_rcu_dereference(event->tp_event->prog_array); 1525 ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt); 1526 mutex_unlock(&bpf_event_mutex); 1527 1528 if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || 1529 copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) 1530 ret = -EFAULT; 1531 1532 kfree(ids); 1533 return ret; 1534 } 1535 1536 extern struct bpf_raw_event_map __start__bpf_raw_tp[]; 1537 extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; 1538 1539 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) 1540 { 1541 struct bpf_raw_event_map *btp = __start__bpf_raw_tp; 1542 1543 for (; btp < __stop__bpf_raw_tp; btp++) { 1544 if (!strcmp(btp->tp->name, name)) 1545 return btp; 1546 } 1547 1548 return bpf_get_raw_tracepoint_module(name); 1549 } 1550 1551 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) 1552 { 1553 struct module *mod = __module_address((unsigned long)btp); 1554 1555 if (mod) 1556 module_put(mod); 1557 } 1558 1559 static __always_inline 1560 void __bpf_trace_run(struct bpf_prog *prog, u64 *args) 1561 { 1562 cant_sleep(); 1563 rcu_read_lock(); 1564 (void) BPF_PROG_RUN(prog, args); 1565 rcu_read_unlock(); 1566 } 1567 1568 #define UNPACK(...) __VA_ARGS__ 1569 #define REPEAT_1(FN, DL, X, ...) FN(X) 1570 #define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) 1571 #define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) 1572 #define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) 1573 #define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) 1574 #define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) 1575 #define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) 1576 #define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) 1577 #define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) 1578 #define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) 1579 #define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) 1580 #define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) 1581 #define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) 1582 1583 #define SARG(X) u64 arg##X 1584 #define COPY(X) args[X] = arg##X 1585 1586 #define __DL_COM (,) 1587 #define __DL_SEM (;) 1588 1589 #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 1590 1591 #define BPF_TRACE_DEFN_x(x) \ 1592 void bpf_trace_run##x(struct bpf_prog *prog, \ 1593 REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ 1594 { \ 1595 u64 args[x]; \ 1596 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ 1597 __bpf_trace_run(prog, args); \ 1598 } \ 1599 EXPORT_SYMBOL_GPL(bpf_trace_run##x) 1600 BPF_TRACE_DEFN_x(1); 1601 BPF_TRACE_DEFN_x(2); 1602 BPF_TRACE_DEFN_x(3); 1603 BPF_TRACE_DEFN_x(4); 1604 BPF_TRACE_DEFN_x(5); 1605 BPF_TRACE_DEFN_x(6); 1606 BPF_TRACE_DEFN_x(7); 1607 BPF_TRACE_DEFN_x(8); 1608 BPF_TRACE_DEFN_x(9); 1609 BPF_TRACE_DEFN_x(10); 1610 BPF_TRACE_DEFN_x(11); 1611 BPF_TRACE_DEFN_x(12); 1612 1613 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1614 { 1615 struct tracepoint *tp = btp->tp; 1616 1617 /* 1618 * check that program doesn't access arguments beyond what's 1619 * available in this tracepoint 1620 */ 1621 if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) 1622 return -EINVAL; 1623 1624 if (prog->aux->max_tp_access > btp->writable_size) 1625 return -EINVAL; 1626 1627 return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); 1628 } 1629 1630 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1631 { 1632 return __bpf_probe_register(btp, prog); 1633 } 1634 1635 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1636 { 1637 return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); 1638 } 1639 1640 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, 1641 u32 *fd_type, const char **buf, 1642 u64 *probe_offset, u64 *probe_addr) 1643 { 1644 bool is_tracepoint, is_syscall_tp; 1645 struct bpf_prog *prog; 1646 int flags, err = 0; 1647 1648 prog = event->prog; 1649 if (!prog) 1650 return -ENOENT; 1651 1652 /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */ 1653 if (prog->type == BPF_PROG_TYPE_PERF_EVENT) 1654 return -EOPNOTSUPP; 1655 1656 *prog_id = prog->aux->id; 1657 flags = event->tp_event->flags; 1658 is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT; 1659 is_syscall_tp = is_syscall_trace_event(event->tp_event); 1660 1661 if (is_tracepoint || is_syscall_tp) { 1662 *buf = is_tracepoint ? event->tp_event->tp->name 1663 : event->tp_event->name; 1664 *fd_type = BPF_FD_TYPE_TRACEPOINT; 1665 *probe_offset = 0x0; 1666 *probe_addr = 0x0; 1667 } else { 1668 /* kprobe/uprobe */ 1669 err = -EOPNOTSUPP; 1670 #ifdef CONFIG_KPROBE_EVENTS 1671 if (flags & TRACE_EVENT_FL_KPROBE) 1672 err = bpf_get_kprobe_info(event, fd_type, buf, 1673 probe_offset, probe_addr, 1674 event->attr.type == PERF_TYPE_TRACEPOINT); 1675 #endif 1676 #ifdef CONFIG_UPROBE_EVENTS 1677 if (flags & TRACE_EVENT_FL_UPROBE) 1678 err = bpf_get_uprobe_info(event, fd_type, buf, 1679 probe_offset, 1680 event->attr.type == PERF_TYPE_TRACEPOINT); 1681 #endif 1682 } 1683 1684 return err; 1685 } 1686 1687 static int __init send_signal_irq_work_init(void) 1688 { 1689 int cpu; 1690 struct send_signal_irq_work *work; 1691 1692 for_each_possible_cpu(cpu) { 1693 work = per_cpu_ptr(&send_signal_work, cpu); 1694 init_irq_work(&work->irq_work, do_bpf_send_signal); 1695 } 1696 return 0; 1697 } 1698 1699 subsys_initcall(send_signal_irq_work_init); 1700 1701 #ifdef CONFIG_MODULES 1702 static int bpf_event_notify(struct notifier_block *nb, unsigned long op, 1703 void *module) 1704 { 1705 struct bpf_trace_module *btm, *tmp; 1706 struct module *mod = module; 1707 1708 if (mod->num_bpf_raw_events == 0 || 1709 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 1710 return 0; 1711 1712 mutex_lock(&bpf_module_mutex); 1713 1714 switch (op) { 1715 case MODULE_STATE_COMING: 1716 btm = kzalloc(sizeof(*btm), GFP_KERNEL); 1717 if (btm) { 1718 btm->module = module; 1719 list_add(&btm->list, &bpf_trace_modules); 1720 } 1721 break; 1722 case MODULE_STATE_GOING: 1723 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) { 1724 if (btm->module == module) { 1725 list_del(&btm->list); 1726 kfree(btm); 1727 break; 1728 } 1729 } 1730 break; 1731 } 1732 1733 mutex_unlock(&bpf_module_mutex); 1734 1735 return 0; 1736 } 1737 1738 static struct notifier_block bpf_module_nb = { 1739 .notifier_call = bpf_event_notify, 1740 }; 1741 1742 static int __init bpf_event_init(void) 1743 { 1744 register_module_notifier(&bpf_module_nb); 1745 return 0; 1746 } 1747 1748 fs_initcall(bpf_event_init); 1749 #endif /* CONFIG_MODULES */ 1750