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 }; 707 708 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); 709 710 static void do_bpf_send_signal(struct irq_work *entry) 711 { 712 struct send_signal_irq_work *work; 713 714 work = container_of(entry, struct send_signal_irq_work, irq_work); 715 group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, PIDTYPE_TGID); 716 } 717 718 BPF_CALL_1(bpf_send_signal, u32, sig) 719 { 720 struct send_signal_irq_work *work = NULL; 721 722 /* Similar to bpf_probe_write_user, task needs to be 723 * in a sound condition and kernel memory access be 724 * permitted in order to send signal to the current 725 * task. 726 */ 727 if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) 728 return -EPERM; 729 if (unlikely(uaccess_kernel())) 730 return -EPERM; 731 if (unlikely(!nmi_uaccess_okay())) 732 return -EPERM; 733 734 if (in_nmi()) { 735 /* Do an early check on signal validity. Otherwise, 736 * the error is lost in deferred irq_work. 737 */ 738 if (unlikely(!valid_signal(sig))) 739 return -EINVAL; 740 741 work = this_cpu_ptr(&send_signal_work); 742 if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY) 743 return -EBUSY; 744 745 /* Add the current task, which is the target of sending signal, 746 * to the irq_work. The current task may change when queued 747 * irq works get executed. 748 */ 749 work->task = current; 750 work->sig = sig; 751 irq_work_queue(&work->irq_work); 752 return 0; 753 } 754 755 return group_send_sig_info(sig, SEND_SIG_PRIV, current, PIDTYPE_TGID); 756 } 757 758 static const struct bpf_func_proto bpf_send_signal_proto = { 759 .func = bpf_send_signal, 760 .gpl_only = false, 761 .ret_type = RET_INTEGER, 762 .arg1_type = ARG_ANYTHING, 763 }; 764 765 static const struct bpf_func_proto * 766 tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 767 { 768 switch (func_id) { 769 case BPF_FUNC_map_lookup_elem: 770 return &bpf_map_lookup_elem_proto; 771 case BPF_FUNC_map_update_elem: 772 return &bpf_map_update_elem_proto; 773 case BPF_FUNC_map_delete_elem: 774 return &bpf_map_delete_elem_proto; 775 case BPF_FUNC_map_push_elem: 776 return &bpf_map_push_elem_proto; 777 case BPF_FUNC_map_pop_elem: 778 return &bpf_map_pop_elem_proto; 779 case BPF_FUNC_map_peek_elem: 780 return &bpf_map_peek_elem_proto; 781 case BPF_FUNC_ktime_get_ns: 782 return &bpf_ktime_get_ns_proto; 783 case BPF_FUNC_tail_call: 784 return &bpf_tail_call_proto; 785 case BPF_FUNC_get_current_pid_tgid: 786 return &bpf_get_current_pid_tgid_proto; 787 case BPF_FUNC_get_current_task: 788 return &bpf_get_current_task_proto; 789 case BPF_FUNC_get_current_uid_gid: 790 return &bpf_get_current_uid_gid_proto; 791 case BPF_FUNC_get_current_comm: 792 return &bpf_get_current_comm_proto; 793 case BPF_FUNC_trace_printk: 794 return bpf_get_trace_printk_proto(); 795 case BPF_FUNC_get_smp_processor_id: 796 return &bpf_get_smp_processor_id_proto; 797 case BPF_FUNC_get_numa_node_id: 798 return &bpf_get_numa_node_id_proto; 799 case BPF_FUNC_perf_event_read: 800 return &bpf_perf_event_read_proto; 801 case BPF_FUNC_probe_write_user: 802 return bpf_get_probe_write_proto(); 803 case BPF_FUNC_current_task_under_cgroup: 804 return &bpf_current_task_under_cgroup_proto; 805 case BPF_FUNC_get_prandom_u32: 806 return &bpf_get_prandom_u32_proto; 807 case BPF_FUNC_probe_read_user: 808 return &bpf_probe_read_user_proto; 809 case BPF_FUNC_probe_read_kernel: 810 return &bpf_probe_read_kernel_proto; 811 case BPF_FUNC_probe_read: 812 return &bpf_probe_read_compat_proto; 813 case BPF_FUNC_probe_read_user_str: 814 return &bpf_probe_read_user_str_proto; 815 case BPF_FUNC_probe_read_kernel_str: 816 return &bpf_probe_read_kernel_str_proto; 817 case BPF_FUNC_probe_read_str: 818 return &bpf_probe_read_compat_str_proto; 819 #ifdef CONFIG_CGROUPS 820 case BPF_FUNC_get_current_cgroup_id: 821 return &bpf_get_current_cgroup_id_proto; 822 #endif 823 case BPF_FUNC_send_signal: 824 return &bpf_send_signal_proto; 825 default: 826 return NULL; 827 } 828 } 829 830 static const struct bpf_func_proto * 831 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 832 { 833 switch (func_id) { 834 case BPF_FUNC_perf_event_output: 835 return &bpf_perf_event_output_proto; 836 case BPF_FUNC_get_stackid: 837 return &bpf_get_stackid_proto; 838 case BPF_FUNC_get_stack: 839 return &bpf_get_stack_proto; 840 case BPF_FUNC_perf_event_read_value: 841 return &bpf_perf_event_read_value_proto; 842 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 843 case BPF_FUNC_override_return: 844 return &bpf_override_return_proto; 845 #endif 846 default: 847 return tracing_func_proto(func_id, prog); 848 } 849 } 850 851 /* bpf+kprobe programs can access fields of 'struct pt_regs' */ 852 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 853 const struct bpf_prog *prog, 854 struct bpf_insn_access_aux *info) 855 { 856 if (off < 0 || off >= sizeof(struct pt_regs)) 857 return false; 858 if (type != BPF_READ) 859 return false; 860 if (off % size != 0) 861 return false; 862 /* 863 * Assertion for 32 bit to make sure last 8 byte access 864 * (BPF_DW) to the last 4 byte member is disallowed. 865 */ 866 if (off + size > sizeof(struct pt_regs)) 867 return false; 868 869 return true; 870 } 871 872 const struct bpf_verifier_ops kprobe_verifier_ops = { 873 .get_func_proto = kprobe_prog_func_proto, 874 .is_valid_access = kprobe_prog_is_valid_access, 875 }; 876 877 const struct bpf_prog_ops kprobe_prog_ops = { 878 }; 879 880 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, 881 u64, flags, void *, data, u64, size) 882 { 883 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 884 885 /* 886 * r1 points to perf tracepoint buffer where first 8 bytes are hidden 887 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it 888 * from there and call the same bpf_perf_event_output() helper inline. 889 */ 890 return ____bpf_perf_event_output(regs, map, flags, data, size); 891 } 892 893 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { 894 .func = bpf_perf_event_output_tp, 895 .gpl_only = true, 896 .ret_type = RET_INTEGER, 897 .arg1_type = ARG_PTR_TO_CTX, 898 .arg2_type = ARG_CONST_MAP_PTR, 899 .arg3_type = ARG_ANYTHING, 900 .arg4_type = ARG_PTR_TO_MEM, 901 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 902 }; 903 904 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, 905 u64, flags) 906 { 907 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 908 909 /* 910 * Same comment as in bpf_perf_event_output_tp(), only that this time 911 * the other helper's function body cannot be inlined due to being 912 * external, thus we need to call raw helper function. 913 */ 914 return bpf_get_stackid((unsigned long) regs, (unsigned long) map, 915 flags, 0, 0); 916 } 917 918 static const struct bpf_func_proto bpf_get_stackid_proto_tp = { 919 .func = bpf_get_stackid_tp, 920 .gpl_only = true, 921 .ret_type = RET_INTEGER, 922 .arg1_type = ARG_PTR_TO_CTX, 923 .arg2_type = ARG_CONST_MAP_PTR, 924 .arg3_type = ARG_ANYTHING, 925 }; 926 927 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size, 928 u64, flags) 929 { 930 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 931 932 return bpf_get_stack((unsigned long) regs, (unsigned long) buf, 933 (unsigned long) size, flags, 0); 934 } 935 936 static const struct bpf_func_proto bpf_get_stack_proto_tp = { 937 .func = bpf_get_stack_tp, 938 .gpl_only = true, 939 .ret_type = RET_INTEGER, 940 .arg1_type = ARG_PTR_TO_CTX, 941 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 942 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 943 .arg4_type = ARG_ANYTHING, 944 }; 945 946 static const struct bpf_func_proto * 947 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 948 { 949 switch (func_id) { 950 case BPF_FUNC_perf_event_output: 951 return &bpf_perf_event_output_proto_tp; 952 case BPF_FUNC_get_stackid: 953 return &bpf_get_stackid_proto_tp; 954 case BPF_FUNC_get_stack: 955 return &bpf_get_stack_proto_tp; 956 default: 957 return tracing_func_proto(func_id, prog); 958 } 959 } 960 961 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, 962 const struct bpf_prog *prog, 963 struct bpf_insn_access_aux *info) 964 { 965 if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) 966 return false; 967 if (type != BPF_READ) 968 return false; 969 if (off % size != 0) 970 return false; 971 972 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); 973 return true; 974 } 975 976 const struct bpf_verifier_ops tracepoint_verifier_ops = { 977 .get_func_proto = tp_prog_func_proto, 978 .is_valid_access = tp_prog_is_valid_access, 979 }; 980 981 const struct bpf_prog_ops tracepoint_prog_ops = { 982 }; 983 984 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx, 985 struct bpf_perf_event_value *, buf, u32, size) 986 { 987 int err = -EINVAL; 988 989 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 990 goto clear; 991 err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, 992 &buf->running); 993 if (unlikely(err)) 994 goto clear; 995 return 0; 996 clear: 997 memset(buf, 0, size); 998 return err; 999 } 1000 1001 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { 1002 .func = bpf_perf_prog_read_value, 1003 .gpl_only = true, 1004 .ret_type = RET_INTEGER, 1005 .arg1_type = ARG_PTR_TO_CTX, 1006 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 1007 .arg3_type = ARG_CONST_SIZE, 1008 }; 1009 1010 static const struct bpf_func_proto * 1011 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1012 { 1013 switch (func_id) { 1014 case BPF_FUNC_perf_event_output: 1015 return &bpf_perf_event_output_proto_tp; 1016 case BPF_FUNC_get_stackid: 1017 return &bpf_get_stackid_proto_tp; 1018 case BPF_FUNC_get_stack: 1019 return &bpf_get_stack_proto_tp; 1020 case BPF_FUNC_perf_prog_read_value: 1021 return &bpf_perf_prog_read_value_proto; 1022 default: 1023 return tracing_func_proto(func_id, prog); 1024 } 1025 } 1026 1027 /* 1028 * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp 1029 * to avoid potential recursive reuse issue when/if tracepoints are added 1030 * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. 1031 * 1032 * Since raw tracepoints run despite bpf_prog_active, support concurrent usage 1033 * in normal, irq, and nmi context. 1034 */ 1035 struct bpf_raw_tp_regs { 1036 struct pt_regs regs[3]; 1037 }; 1038 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); 1039 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); 1040 static struct pt_regs *get_bpf_raw_tp_regs(void) 1041 { 1042 struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); 1043 int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); 1044 1045 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { 1046 this_cpu_dec(bpf_raw_tp_nest_level); 1047 return ERR_PTR(-EBUSY); 1048 } 1049 1050 return &tp_regs->regs[nest_level - 1]; 1051 } 1052 1053 static void put_bpf_raw_tp_regs(void) 1054 { 1055 this_cpu_dec(bpf_raw_tp_nest_level); 1056 } 1057 1058 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, 1059 struct bpf_map *, map, u64, flags, void *, data, u64, size) 1060 { 1061 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1062 int ret; 1063 1064 if (IS_ERR(regs)) 1065 return PTR_ERR(regs); 1066 1067 perf_fetch_caller_regs(regs); 1068 ret = ____bpf_perf_event_output(regs, map, flags, data, size); 1069 1070 put_bpf_raw_tp_regs(); 1071 return ret; 1072 } 1073 1074 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { 1075 .func = bpf_perf_event_output_raw_tp, 1076 .gpl_only = true, 1077 .ret_type = RET_INTEGER, 1078 .arg1_type = ARG_PTR_TO_CTX, 1079 .arg2_type = ARG_CONST_MAP_PTR, 1080 .arg3_type = ARG_ANYTHING, 1081 .arg4_type = ARG_PTR_TO_MEM, 1082 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 1083 }; 1084 1085 extern const struct bpf_func_proto bpf_skb_output_proto; 1086 1087 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, 1088 struct bpf_map *, map, u64, flags) 1089 { 1090 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1091 int ret; 1092 1093 if (IS_ERR(regs)) 1094 return PTR_ERR(regs); 1095 1096 perf_fetch_caller_regs(regs); 1097 /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ 1098 ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, 1099 flags, 0, 0); 1100 put_bpf_raw_tp_regs(); 1101 return ret; 1102 } 1103 1104 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { 1105 .func = bpf_get_stackid_raw_tp, 1106 .gpl_only = true, 1107 .ret_type = RET_INTEGER, 1108 .arg1_type = ARG_PTR_TO_CTX, 1109 .arg2_type = ARG_CONST_MAP_PTR, 1110 .arg3_type = ARG_ANYTHING, 1111 }; 1112 1113 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, 1114 void *, buf, u32, size, u64, flags) 1115 { 1116 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1117 int ret; 1118 1119 if (IS_ERR(regs)) 1120 return PTR_ERR(regs); 1121 1122 perf_fetch_caller_regs(regs); 1123 ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, 1124 (unsigned long) size, flags, 0); 1125 put_bpf_raw_tp_regs(); 1126 return ret; 1127 } 1128 1129 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { 1130 .func = bpf_get_stack_raw_tp, 1131 .gpl_only = true, 1132 .ret_type = RET_INTEGER, 1133 .arg1_type = ARG_PTR_TO_CTX, 1134 .arg2_type = ARG_PTR_TO_MEM, 1135 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1136 .arg4_type = ARG_ANYTHING, 1137 }; 1138 1139 static const struct bpf_func_proto * 1140 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1141 { 1142 switch (func_id) { 1143 case BPF_FUNC_perf_event_output: 1144 return &bpf_perf_event_output_proto_raw_tp; 1145 case BPF_FUNC_get_stackid: 1146 return &bpf_get_stackid_proto_raw_tp; 1147 case BPF_FUNC_get_stack: 1148 return &bpf_get_stack_proto_raw_tp; 1149 default: 1150 return tracing_func_proto(func_id, prog); 1151 } 1152 } 1153 1154 static const struct bpf_func_proto * 1155 tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1156 { 1157 switch (func_id) { 1158 #ifdef CONFIG_NET 1159 case BPF_FUNC_skb_output: 1160 return &bpf_skb_output_proto; 1161 #endif 1162 default: 1163 return raw_tp_prog_func_proto(func_id, prog); 1164 } 1165 } 1166 1167 static bool raw_tp_prog_is_valid_access(int off, int size, 1168 enum bpf_access_type type, 1169 const struct bpf_prog *prog, 1170 struct bpf_insn_access_aux *info) 1171 { 1172 if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) 1173 return false; 1174 if (type != BPF_READ) 1175 return false; 1176 if (off % size != 0) 1177 return false; 1178 return true; 1179 } 1180 1181 static bool tracing_prog_is_valid_access(int off, int size, 1182 enum bpf_access_type type, 1183 const struct bpf_prog *prog, 1184 struct bpf_insn_access_aux *info) 1185 { 1186 if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) 1187 return false; 1188 if (type != BPF_READ) 1189 return false; 1190 if (off % size != 0) 1191 return false; 1192 return btf_ctx_access(off, size, type, prog, info); 1193 } 1194 1195 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { 1196 .get_func_proto = raw_tp_prog_func_proto, 1197 .is_valid_access = raw_tp_prog_is_valid_access, 1198 }; 1199 1200 const struct bpf_prog_ops raw_tracepoint_prog_ops = { 1201 }; 1202 1203 const struct bpf_verifier_ops tracing_verifier_ops = { 1204 .get_func_proto = tracing_prog_func_proto, 1205 .is_valid_access = tracing_prog_is_valid_access, 1206 }; 1207 1208 const struct bpf_prog_ops tracing_prog_ops = { 1209 }; 1210 1211 static bool raw_tp_writable_prog_is_valid_access(int off, int size, 1212 enum bpf_access_type type, 1213 const struct bpf_prog *prog, 1214 struct bpf_insn_access_aux *info) 1215 { 1216 if (off == 0) { 1217 if (size != sizeof(u64) || type != BPF_READ) 1218 return false; 1219 info->reg_type = PTR_TO_TP_BUFFER; 1220 } 1221 return raw_tp_prog_is_valid_access(off, size, type, prog, info); 1222 } 1223 1224 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { 1225 .get_func_proto = raw_tp_prog_func_proto, 1226 .is_valid_access = raw_tp_writable_prog_is_valid_access, 1227 }; 1228 1229 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { 1230 }; 1231 1232 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1233 const struct bpf_prog *prog, 1234 struct bpf_insn_access_aux *info) 1235 { 1236 const int size_u64 = sizeof(u64); 1237 1238 if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) 1239 return false; 1240 if (type != BPF_READ) 1241 return false; 1242 if (off % size != 0) { 1243 if (sizeof(unsigned long) != 4) 1244 return false; 1245 if (size != 8) 1246 return false; 1247 if (off % size != 4) 1248 return false; 1249 } 1250 1251 switch (off) { 1252 case bpf_ctx_range(struct bpf_perf_event_data, sample_period): 1253 bpf_ctx_record_field_size(info, size_u64); 1254 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1255 return false; 1256 break; 1257 case bpf_ctx_range(struct bpf_perf_event_data, addr): 1258 bpf_ctx_record_field_size(info, size_u64); 1259 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1260 return false; 1261 break; 1262 default: 1263 if (size != sizeof(long)) 1264 return false; 1265 } 1266 1267 return true; 1268 } 1269 1270 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, 1271 const struct bpf_insn *si, 1272 struct bpf_insn *insn_buf, 1273 struct bpf_prog *prog, u32 *target_size) 1274 { 1275 struct bpf_insn *insn = insn_buf; 1276 1277 switch (si->off) { 1278 case offsetof(struct bpf_perf_event_data, sample_period): 1279 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1280 data), si->dst_reg, si->src_reg, 1281 offsetof(struct bpf_perf_event_data_kern, data)); 1282 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1283 bpf_target_off(struct perf_sample_data, period, 8, 1284 target_size)); 1285 break; 1286 case offsetof(struct bpf_perf_event_data, addr): 1287 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1288 data), si->dst_reg, si->src_reg, 1289 offsetof(struct bpf_perf_event_data_kern, data)); 1290 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1291 bpf_target_off(struct perf_sample_data, addr, 8, 1292 target_size)); 1293 break; 1294 default: 1295 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1296 regs), si->dst_reg, si->src_reg, 1297 offsetof(struct bpf_perf_event_data_kern, regs)); 1298 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, 1299 si->off); 1300 break; 1301 } 1302 1303 return insn - insn_buf; 1304 } 1305 1306 const struct bpf_verifier_ops perf_event_verifier_ops = { 1307 .get_func_proto = pe_prog_func_proto, 1308 .is_valid_access = pe_prog_is_valid_access, 1309 .convert_ctx_access = pe_prog_convert_ctx_access, 1310 }; 1311 1312 const struct bpf_prog_ops perf_event_prog_ops = { 1313 }; 1314 1315 static DEFINE_MUTEX(bpf_event_mutex); 1316 1317 #define BPF_TRACE_MAX_PROGS 64 1318 1319 int perf_event_attach_bpf_prog(struct perf_event *event, 1320 struct bpf_prog *prog) 1321 { 1322 struct bpf_prog_array *old_array; 1323 struct bpf_prog_array *new_array; 1324 int ret = -EEXIST; 1325 1326 /* 1327 * Kprobe override only works if they are on the function entry, 1328 * and only if they are on the opt-in list. 1329 */ 1330 if (prog->kprobe_override && 1331 (!trace_kprobe_on_func_entry(event->tp_event) || 1332 !trace_kprobe_error_injectable(event->tp_event))) 1333 return -EINVAL; 1334 1335 mutex_lock(&bpf_event_mutex); 1336 1337 if (event->prog) 1338 goto unlock; 1339 1340 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1341 if (old_array && 1342 bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { 1343 ret = -E2BIG; 1344 goto unlock; 1345 } 1346 1347 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); 1348 if (ret < 0) 1349 goto unlock; 1350 1351 /* set the new array to event->tp_event and set event->prog */ 1352 event->prog = prog; 1353 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1354 bpf_prog_array_free(old_array); 1355 1356 unlock: 1357 mutex_unlock(&bpf_event_mutex); 1358 return ret; 1359 } 1360 1361 void perf_event_detach_bpf_prog(struct perf_event *event) 1362 { 1363 struct bpf_prog_array *old_array; 1364 struct bpf_prog_array *new_array; 1365 int ret; 1366 1367 mutex_lock(&bpf_event_mutex); 1368 1369 if (!event->prog) 1370 goto unlock; 1371 1372 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1373 ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); 1374 if (ret == -ENOENT) 1375 goto unlock; 1376 if (ret < 0) { 1377 bpf_prog_array_delete_safe(old_array, event->prog); 1378 } else { 1379 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1380 bpf_prog_array_free(old_array); 1381 } 1382 1383 bpf_prog_put(event->prog); 1384 event->prog = NULL; 1385 1386 unlock: 1387 mutex_unlock(&bpf_event_mutex); 1388 } 1389 1390 int perf_event_query_prog_array(struct perf_event *event, void __user *info) 1391 { 1392 struct perf_event_query_bpf __user *uquery = info; 1393 struct perf_event_query_bpf query = {}; 1394 struct bpf_prog_array *progs; 1395 u32 *ids, prog_cnt, ids_len; 1396 int ret; 1397 1398 if (!capable(CAP_SYS_ADMIN)) 1399 return -EPERM; 1400 if (event->attr.type != PERF_TYPE_TRACEPOINT) 1401 return -EINVAL; 1402 if (copy_from_user(&query, uquery, sizeof(query))) 1403 return -EFAULT; 1404 1405 ids_len = query.ids_len; 1406 if (ids_len > BPF_TRACE_MAX_PROGS) 1407 return -E2BIG; 1408 ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); 1409 if (!ids) 1410 return -ENOMEM; 1411 /* 1412 * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which 1413 * is required when user only wants to check for uquery->prog_cnt. 1414 * There is no need to check for it since the case is handled 1415 * gracefully in bpf_prog_array_copy_info. 1416 */ 1417 1418 mutex_lock(&bpf_event_mutex); 1419 progs = bpf_event_rcu_dereference(event->tp_event->prog_array); 1420 ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt); 1421 mutex_unlock(&bpf_event_mutex); 1422 1423 if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || 1424 copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) 1425 ret = -EFAULT; 1426 1427 kfree(ids); 1428 return ret; 1429 } 1430 1431 extern struct bpf_raw_event_map __start__bpf_raw_tp[]; 1432 extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; 1433 1434 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) 1435 { 1436 struct bpf_raw_event_map *btp = __start__bpf_raw_tp; 1437 1438 for (; btp < __stop__bpf_raw_tp; btp++) { 1439 if (!strcmp(btp->tp->name, name)) 1440 return btp; 1441 } 1442 1443 return bpf_get_raw_tracepoint_module(name); 1444 } 1445 1446 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) 1447 { 1448 struct module *mod = __module_address((unsigned long)btp); 1449 1450 if (mod) 1451 module_put(mod); 1452 } 1453 1454 static __always_inline 1455 void __bpf_trace_run(struct bpf_prog *prog, u64 *args) 1456 { 1457 rcu_read_lock(); 1458 preempt_disable(); 1459 (void) BPF_PROG_RUN(prog, args); 1460 preempt_enable(); 1461 rcu_read_unlock(); 1462 } 1463 1464 #define UNPACK(...) __VA_ARGS__ 1465 #define REPEAT_1(FN, DL, X, ...) FN(X) 1466 #define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) 1467 #define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) 1468 #define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) 1469 #define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) 1470 #define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) 1471 #define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) 1472 #define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) 1473 #define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) 1474 #define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) 1475 #define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) 1476 #define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) 1477 #define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) 1478 1479 #define SARG(X) u64 arg##X 1480 #define COPY(X) args[X] = arg##X 1481 1482 #define __DL_COM (,) 1483 #define __DL_SEM (;) 1484 1485 #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 1486 1487 #define BPF_TRACE_DEFN_x(x) \ 1488 void bpf_trace_run##x(struct bpf_prog *prog, \ 1489 REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ 1490 { \ 1491 u64 args[x]; \ 1492 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ 1493 __bpf_trace_run(prog, args); \ 1494 } \ 1495 EXPORT_SYMBOL_GPL(bpf_trace_run##x) 1496 BPF_TRACE_DEFN_x(1); 1497 BPF_TRACE_DEFN_x(2); 1498 BPF_TRACE_DEFN_x(3); 1499 BPF_TRACE_DEFN_x(4); 1500 BPF_TRACE_DEFN_x(5); 1501 BPF_TRACE_DEFN_x(6); 1502 BPF_TRACE_DEFN_x(7); 1503 BPF_TRACE_DEFN_x(8); 1504 BPF_TRACE_DEFN_x(9); 1505 BPF_TRACE_DEFN_x(10); 1506 BPF_TRACE_DEFN_x(11); 1507 BPF_TRACE_DEFN_x(12); 1508 1509 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1510 { 1511 struct tracepoint *tp = btp->tp; 1512 1513 /* 1514 * check that program doesn't access arguments beyond what's 1515 * available in this tracepoint 1516 */ 1517 if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) 1518 return -EINVAL; 1519 1520 if (prog->aux->max_tp_access > btp->writable_size) 1521 return -EINVAL; 1522 1523 return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); 1524 } 1525 1526 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1527 { 1528 return __bpf_probe_register(btp, prog); 1529 } 1530 1531 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1532 { 1533 return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); 1534 } 1535 1536 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, 1537 u32 *fd_type, const char **buf, 1538 u64 *probe_offset, u64 *probe_addr) 1539 { 1540 bool is_tracepoint, is_syscall_tp; 1541 struct bpf_prog *prog; 1542 int flags, err = 0; 1543 1544 prog = event->prog; 1545 if (!prog) 1546 return -ENOENT; 1547 1548 /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */ 1549 if (prog->type == BPF_PROG_TYPE_PERF_EVENT) 1550 return -EOPNOTSUPP; 1551 1552 *prog_id = prog->aux->id; 1553 flags = event->tp_event->flags; 1554 is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT; 1555 is_syscall_tp = is_syscall_trace_event(event->tp_event); 1556 1557 if (is_tracepoint || is_syscall_tp) { 1558 *buf = is_tracepoint ? event->tp_event->tp->name 1559 : event->tp_event->name; 1560 *fd_type = BPF_FD_TYPE_TRACEPOINT; 1561 *probe_offset = 0x0; 1562 *probe_addr = 0x0; 1563 } else { 1564 /* kprobe/uprobe */ 1565 err = -EOPNOTSUPP; 1566 #ifdef CONFIG_KPROBE_EVENTS 1567 if (flags & TRACE_EVENT_FL_KPROBE) 1568 err = bpf_get_kprobe_info(event, fd_type, buf, 1569 probe_offset, probe_addr, 1570 event->attr.type == PERF_TYPE_TRACEPOINT); 1571 #endif 1572 #ifdef CONFIG_UPROBE_EVENTS 1573 if (flags & TRACE_EVENT_FL_UPROBE) 1574 err = bpf_get_uprobe_info(event, fd_type, buf, 1575 probe_offset, 1576 event->attr.type == PERF_TYPE_TRACEPOINT); 1577 #endif 1578 } 1579 1580 return err; 1581 } 1582 1583 static int __init send_signal_irq_work_init(void) 1584 { 1585 int cpu; 1586 struct send_signal_irq_work *work; 1587 1588 for_each_possible_cpu(cpu) { 1589 work = per_cpu_ptr(&send_signal_work, cpu); 1590 init_irq_work(&work->irq_work, do_bpf_send_signal); 1591 } 1592 return 0; 1593 } 1594 1595 subsys_initcall(send_signal_irq_work_init); 1596 1597 #ifdef CONFIG_MODULES 1598 static int bpf_event_notify(struct notifier_block *nb, unsigned long op, 1599 void *module) 1600 { 1601 struct bpf_trace_module *btm, *tmp; 1602 struct module *mod = module; 1603 1604 if (mod->num_bpf_raw_events == 0 || 1605 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 1606 return 0; 1607 1608 mutex_lock(&bpf_module_mutex); 1609 1610 switch (op) { 1611 case MODULE_STATE_COMING: 1612 btm = kzalloc(sizeof(*btm), GFP_KERNEL); 1613 if (btm) { 1614 btm->module = module; 1615 list_add(&btm->list, &bpf_trace_modules); 1616 } 1617 break; 1618 case MODULE_STATE_GOING: 1619 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) { 1620 if (btm->module == module) { 1621 list_del(&btm->list); 1622 kfree(btm); 1623 break; 1624 } 1625 } 1626 break; 1627 } 1628 1629 mutex_unlock(&bpf_module_mutex); 1630 1631 return 0; 1632 } 1633 1634 static struct notifier_block bpf_module_nb = { 1635 .notifier_call = bpf_event_notify, 1636 }; 1637 1638 static int __init bpf_event_init(void) 1639 { 1640 register_module_notifier(&bpf_module_nb); 1641 return 0; 1642 } 1643 1644 fs_initcall(bpf_event_init); 1645 #endif /* CONFIG_MODULES */ 1646