1 /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com 2 * Copyright (c) 2016 Facebook 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of version 2 of the GNU General Public 6 * License as published by the Free Software Foundation. 7 */ 8 #include <linux/kernel.h> 9 #include <linux/types.h> 10 #include <linux/slab.h> 11 #include <linux/bpf.h> 12 #include <linux/bpf_perf_event.h> 13 #include <linux/filter.h> 14 #include <linux/uaccess.h> 15 #include <linux/ctype.h> 16 #include "trace.h" 17 18 /** 19 * trace_call_bpf - invoke BPF program 20 * @prog: BPF program 21 * @ctx: opaque context pointer 22 * 23 * kprobe handlers execute BPF programs via this helper. 24 * Can be used from static tracepoints in the future. 25 * 26 * Return: BPF programs always return an integer which is interpreted by 27 * kprobe handler as: 28 * 0 - return from kprobe (event is filtered out) 29 * 1 - store kprobe event into ring buffer 30 * Other values are reserved and currently alias to 1 31 */ 32 unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx) 33 { 34 unsigned int ret; 35 36 if (in_nmi()) /* not supported yet */ 37 return 1; 38 39 preempt_disable(); 40 41 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { 42 /* 43 * since some bpf program is already running on this cpu, 44 * don't call into another bpf program (same or different) 45 * and don't send kprobe event into ring-buffer, 46 * so return zero here 47 */ 48 ret = 0; 49 goto out; 50 } 51 52 rcu_read_lock(); 53 ret = BPF_PROG_RUN(prog, ctx); 54 rcu_read_unlock(); 55 56 out: 57 __this_cpu_dec(bpf_prog_active); 58 preempt_enable(); 59 60 return ret; 61 } 62 EXPORT_SYMBOL_GPL(trace_call_bpf); 63 64 BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) 65 { 66 int ret; 67 68 ret = probe_kernel_read(dst, unsafe_ptr, size); 69 if (unlikely(ret < 0)) 70 memset(dst, 0, size); 71 72 return ret; 73 } 74 75 static const struct bpf_func_proto bpf_probe_read_proto = { 76 .func = bpf_probe_read, 77 .gpl_only = true, 78 .ret_type = RET_INTEGER, 79 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 80 .arg2_type = ARG_CONST_SIZE, 81 .arg3_type = ARG_ANYTHING, 82 }; 83 84 BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, 85 u32, size) 86 { 87 /* 88 * Ensure we're in user context which is safe for the helper to 89 * run. This helper has no business in a kthread. 90 * 91 * access_ok() should prevent writing to non-user memory, but in 92 * some situations (nommu, temporary switch, etc) access_ok() does 93 * not provide enough validation, hence the check on KERNEL_DS. 94 */ 95 96 if (unlikely(in_interrupt() || 97 current->flags & (PF_KTHREAD | PF_EXITING))) 98 return -EPERM; 99 if (unlikely(uaccess_kernel())) 100 return -EPERM; 101 if (!access_ok(VERIFY_WRITE, unsafe_ptr, size)) 102 return -EPERM; 103 104 return probe_kernel_write(unsafe_ptr, src, size); 105 } 106 107 static const struct bpf_func_proto bpf_probe_write_user_proto = { 108 .func = bpf_probe_write_user, 109 .gpl_only = true, 110 .ret_type = RET_INTEGER, 111 .arg1_type = ARG_ANYTHING, 112 .arg2_type = ARG_PTR_TO_MEM, 113 .arg3_type = ARG_CONST_SIZE, 114 }; 115 116 static const struct bpf_func_proto *bpf_get_probe_write_proto(void) 117 { 118 pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", 119 current->comm, task_pid_nr(current)); 120 121 return &bpf_probe_write_user_proto; 122 } 123 124 /* 125 * Only limited trace_printk() conversion specifiers allowed: 126 * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s 127 */ 128 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, 129 u64, arg2, u64, arg3) 130 { 131 bool str_seen = false; 132 int mod[3] = {}; 133 int fmt_cnt = 0; 134 u64 unsafe_addr; 135 char buf[64]; 136 int i; 137 138 /* 139 * bpf_check()->check_func_arg()->check_stack_boundary() 140 * guarantees that fmt points to bpf program stack, 141 * fmt_size bytes of it were initialized and fmt_size > 0 142 */ 143 if (fmt[--fmt_size] != 0) 144 return -EINVAL; 145 146 /* check format string for allowed specifiers */ 147 for (i = 0; i < fmt_size; i++) { 148 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) 149 return -EINVAL; 150 151 if (fmt[i] != '%') 152 continue; 153 154 if (fmt_cnt >= 3) 155 return -EINVAL; 156 157 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ 158 i++; 159 if (fmt[i] == 'l') { 160 mod[fmt_cnt]++; 161 i++; 162 } else if (fmt[i] == 'p' || fmt[i] == 's') { 163 mod[fmt_cnt]++; 164 i++; 165 if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0) 166 return -EINVAL; 167 fmt_cnt++; 168 if (fmt[i - 1] == 's') { 169 if (str_seen) 170 /* allow only one '%s' per fmt string */ 171 return -EINVAL; 172 str_seen = true; 173 174 switch (fmt_cnt) { 175 case 1: 176 unsafe_addr = arg1; 177 arg1 = (long) buf; 178 break; 179 case 2: 180 unsafe_addr = arg2; 181 arg2 = (long) buf; 182 break; 183 case 3: 184 unsafe_addr = arg3; 185 arg3 = (long) buf; 186 break; 187 } 188 buf[0] = 0; 189 strncpy_from_unsafe(buf, 190 (void *) (long) unsafe_addr, 191 sizeof(buf)); 192 } 193 continue; 194 } 195 196 if (fmt[i] == 'l') { 197 mod[fmt_cnt]++; 198 i++; 199 } 200 201 if (fmt[i] != 'i' && fmt[i] != 'd' && 202 fmt[i] != 'u' && fmt[i] != 'x') 203 return -EINVAL; 204 fmt_cnt++; 205 } 206 207 /* Horrid workaround for getting va_list handling working with different 208 * argument type combinations generically for 32 and 64 bit archs. 209 */ 210 #define __BPF_TP_EMIT() __BPF_ARG3_TP() 211 #define __BPF_TP(...) \ 212 __trace_printk(1 /* Fake ip will not be printed. */, \ 213 fmt, ##__VA_ARGS__) 214 215 #define __BPF_ARG1_TP(...) \ 216 ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ 217 ? __BPF_TP(arg1, ##__VA_ARGS__) \ 218 : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ 219 ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ 220 : __BPF_TP((u32)arg1, ##__VA_ARGS__))) 221 222 #define __BPF_ARG2_TP(...) \ 223 ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ 224 ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ 225 : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ 226 ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ 227 : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) 228 229 #define __BPF_ARG3_TP(...) \ 230 ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ 231 ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ 232 : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ 233 ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ 234 : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) 235 236 return __BPF_TP_EMIT(); 237 } 238 239 static const struct bpf_func_proto bpf_trace_printk_proto = { 240 .func = bpf_trace_printk, 241 .gpl_only = true, 242 .ret_type = RET_INTEGER, 243 .arg1_type = ARG_PTR_TO_MEM, 244 .arg2_type = ARG_CONST_SIZE, 245 }; 246 247 const struct bpf_func_proto *bpf_get_trace_printk_proto(void) 248 { 249 /* 250 * this program might be calling bpf_trace_printk, 251 * so allocate per-cpu printk buffers 252 */ 253 trace_printk_init_buffers(); 254 255 return &bpf_trace_printk_proto; 256 } 257 258 static __always_inline int 259 get_map_perf_counter(struct bpf_map *map, u64 flags, 260 u64 *value, u64 *enabled, u64 *running) 261 { 262 struct bpf_array *array = container_of(map, struct bpf_array, map); 263 unsigned int cpu = smp_processor_id(); 264 u64 index = flags & BPF_F_INDEX_MASK; 265 struct bpf_event_entry *ee; 266 267 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) 268 return -EINVAL; 269 if (index == BPF_F_CURRENT_CPU) 270 index = cpu; 271 if (unlikely(index >= array->map.max_entries)) 272 return -E2BIG; 273 274 ee = READ_ONCE(array->ptrs[index]); 275 if (!ee) 276 return -ENOENT; 277 278 return perf_event_read_local(ee->event, value, enabled, running); 279 } 280 281 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) 282 { 283 u64 value = 0; 284 int err; 285 286 err = get_map_perf_counter(map, flags, &value, NULL, NULL); 287 /* 288 * this api is ugly since we miss [-22..-2] range of valid 289 * counter values, but that's uapi 290 */ 291 if (err) 292 return err; 293 return value; 294 } 295 296 static const struct bpf_func_proto bpf_perf_event_read_proto = { 297 .func = bpf_perf_event_read, 298 .gpl_only = true, 299 .ret_type = RET_INTEGER, 300 .arg1_type = ARG_CONST_MAP_PTR, 301 .arg2_type = ARG_ANYTHING, 302 }; 303 304 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags, 305 struct bpf_perf_event_value *, buf, u32, size) 306 { 307 int err = -EINVAL; 308 309 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 310 goto clear; 311 err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled, 312 &buf->running); 313 if (unlikely(err)) 314 goto clear; 315 return 0; 316 clear: 317 memset(buf, 0, size); 318 return err; 319 } 320 321 static const struct bpf_func_proto bpf_perf_event_read_value_proto = { 322 .func = bpf_perf_event_read_value, 323 .gpl_only = true, 324 .ret_type = RET_INTEGER, 325 .arg1_type = ARG_CONST_MAP_PTR, 326 .arg2_type = ARG_ANYTHING, 327 .arg3_type = ARG_PTR_TO_UNINIT_MEM, 328 .arg4_type = ARG_CONST_SIZE, 329 }; 330 331 static DEFINE_PER_CPU(struct perf_sample_data, bpf_sd); 332 333 static __always_inline u64 334 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, 335 u64 flags, struct perf_raw_record *raw) 336 { 337 struct bpf_array *array = container_of(map, struct bpf_array, map); 338 struct perf_sample_data *sd = this_cpu_ptr(&bpf_sd); 339 unsigned int cpu = smp_processor_id(); 340 u64 index = flags & BPF_F_INDEX_MASK; 341 struct bpf_event_entry *ee; 342 struct perf_event *event; 343 344 if (index == BPF_F_CURRENT_CPU) 345 index = cpu; 346 if (unlikely(index >= array->map.max_entries)) 347 return -E2BIG; 348 349 ee = READ_ONCE(array->ptrs[index]); 350 if (!ee) 351 return -ENOENT; 352 353 event = ee->event; 354 if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || 355 event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) 356 return -EINVAL; 357 358 if (unlikely(event->oncpu != cpu)) 359 return -EOPNOTSUPP; 360 361 perf_sample_data_init(sd, 0, 0); 362 sd->raw = raw; 363 perf_event_output(event, sd, regs); 364 return 0; 365 } 366 367 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, 368 u64, flags, void *, data, u64, size) 369 { 370 struct perf_raw_record raw = { 371 .frag = { 372 .size = size, 373 .data = data, 374 }, 375 }; 376 377 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) 378 return -EINVAL; 379 380 return __bpf_perf_event_output(regs, map, flags, &raw); 381 } 382 383 static const struct bpf_func_proto bpf_perf_event_output_proto = { 384 .func = bpf_perf_event_output, 385 .gpl_only = true, 386 .ret_type = RET_INTEGER, 387 .arg1_type = ARG_PTR_TO_CTX, 388 .arg2_type = ARG_CONST_MAP_PTR, 389 .arg3_type = ARG_ANYTHING, 390 .arg4_type = ARG_PTR_TO_MEM, 391 .arg5_type = ARG_CONST_SIZE, 392 }; 393 394 static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs); 395 396 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 397 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 398 { 399 struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs); 400 struct perf_raw_frag frag = { 401 .copy = ctx_copy, 402 .size = ctx_size, 403 .data = ctx, 404 }; 405 struct perf_raw_record raw = { 406 .frag = { 407 { 408 .next = ctx_size ? &frag : NULL, 409 }, 410 .size = meta_size, 411 .data = meta, 412 }, 413 }; 414 415 perf_fetch_caller_regs(regs); 416 417 return __bpf_perf_event_output(regs, map, flags, &raw); 418 } 419 420 BPF_CALL_0(bpf_get_current_task) 421 { 422 return (long) current; 423 } 424 425 static const struct bpf_func_proto bpf_get_current_task_proto = { 426 .func = bpf_get_current_task, 427 .gpl_only = true, 428 .ret_type = RET_INTEGER, 429 }; 430 431 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) 432 { 433 struct bpf_array *array = container_of(map, struct bpf_array, map); 434 struct cgroup *cgrp; 435 436 if (unlikely(in_interrupt())) 437 return -EINVAL; 438 if (unlikely(idx >= array->map.max_entries)) 439 return -E2BIG; 440 441 cgrp = READ_ONCE(array->ptrs[idx]); 442 if (unlikely(!cgrp)) 443 return -EAGAIN; 444 445 return task_under_cgroup_hierarchy(current, cgrp); 446 } 447 448 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { 449 .func = bpf_current_task_under_cgroup, 450 .gpl_only = false, 451 .ret_type = RET_INTEGER, 452 .arg1_type = ARG_CONST_MAP_PTR, 453 .arg2_type = ARG_ANYTHING, 454 }; 455 456 BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size, 457 const void *, unsafe_ptr) 458 { 459 int ret; 460 461 /* 462 * The strncpy_from_unsafe() call will likely not fill the entire 463 * buffer, but that's okay in this circumstance as we're probing 464 * arbitrary memory anyway similar to bpf_probe_read() and might 465 * as well probe the stack. Thus, memory is explicitly cleared 466 * only in error case, so that improper users ignoring return 467 * code altogether don't copy garbage; otherwise length of string 468 * is returned that can be used for bpf_perf_event_output() et al. 469 */ 470 ret = strncpy_from_unsafe(dst, unsafe_ptr, size); 471 if (unlikely(ret < 0)) 472 memset(dst, 0, size); 473 474 return ret; 475 } 476 477 static const struct bpf_func_proto bpf_probe_read_str_proto = { 478 .func = bpf_probe_read_str, 479 .gpl_only = true, 480 .ret_type = RET_INTEGER, 481 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 482 .arg2_type = ARG_CONST_SIZE, 483 .arg3_type = ARG_ANYTHING, 484 }; 485 486 static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) 487 { 488 switch (func_id) { 489 case BPF_FUNC_map_lookup_elem: 490 return &bpf_map_lookup_elem_proto; 491 case BPF_FUNC_map_update_elem: 492 return &bpf_map_update_elem_proto; 493 case BPF_FUNC_map_delete_elem: 494 return &bpf_map_delete_elem_proto; 495 case BPF_FUNC_probe_read: 496 return &bpf_probe_read_proto; 497 case BPF_FUNC_ktime_get_ns: 498 return &bpf_ktime_get_ns_proto; 499 case BPF_FUNC_tail_call: 500 return &bpf_tail_call_proto; 501 case BPF_FUNC_get_current_pid_tgid: 502 return &bpf_get_current_pid_tgid_proto; 503 case BPF_FUNC_get_current_task: 504 return &bpf_get_current_task_proto; 505 case BPF_FUNC_get_current_uid_gid: 506 return &bpf_get_current_uid_gid_proto; 507 case BPF_FUNC_get_current_comm: 508 return &bpf_get_current_comm_proto; 509 case BPF_FUNC_trace_printk: 510 return bpf_get_trace_printk_proto(); 511 case BPF_FUNC_get_smp_processor_id: 512 return &bpf_get_smp_processor_id_proto; 513 case BPF_FUNC_get_numa_node_id: 514 return &bpf_get_numa_node_id_proto; 515 case BPF_FUNC_perf_event_read: 516 return &bpf_perf_event_read_proto; 517 case BPF_FUNC_probe_write_user: 518 return bpf_get_probe_write_proto(); 519 case BPF_FUNC_current_task_under_cgroup: 520 return &bpf_current_task_under_cgroup_proto; 521 case BPF_FUNC_get_prandom_u32: 522 return &bpf_get_prandom_u32_proto; 523 case BPF_FUNC_probe_read_str: 524 return &bpf_probe_read_str_proto; 525 default: 526 return NULL; 527 } 528 } 529 530 static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id) 531 { 532 switch (func_id) { 533 case BPF_FUNC_perf_event_output: 534 return &bpf_perf_event_output_proto; 535 case BPF_FUNC_get_stackid: 536 return &bpf_get_stackid_proto; 537 case BPF_FUNC_perf_event_read_value: 538 return &bpf_perf_event_read_value_proto; 539 default: 540 return tracing_func_proto(func_id); 541 } 542 } 543 544 /* bpf+kprobe programs can access fields of 'struct pt_regs' */ 545 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 546 struct bpf_insn_access_aux *info) 547 { 548 if (off < 0 || off >= sizeof(struct pt_regs)) 549 return false; 550 if (type != BPF_READ) 551 return false; 552 if (off % size != 0) 553 return false; 554 /* 555 * Assertion for 32 bit to make sure last 8 byte access 556 * (BPF_DW) to the last 4 byte member is disallowed. 557 */ 558 if (off + size > sizeof(struct pt_regs)) 559 return false; 560 561 return true; 562 } 563 564 const struct bpf_verifier_ops kprobe_prog_ops = { 565 .get_func_proto = kprobe_prog_func_proto, 566 .is_valid_access = kprobe_prog_is_valid_access, 567 }; 568 569 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, 570 u64, flags, void *, data, u64, size) 571 { 572 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 573 574 /* 575 * r1 points to perf tracepoint buffer where first 8 bytes are hidden 576 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it 577 * from there and call the same bpf_perf_event_output() helper inline. 578 */ 579 return ____bpf_perf_event_output(regs, map, flags, data, size); 580 } 581 582 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { 583 .func = bpf_perf_event_output_tp, 584 .gpl_only = true, 585 .ret_type = RET_INTEGER, 586 .arg1_type = ARG_PTR_TO_CTX, 587 .arg2_type = ARG_CONST_MAP_PTR, 588 .arg3_type = ARG_ANYTHING, 589 .arg4_type = ARG_PTR_TO_MEM, 590 .arg5_type = ARG_CONST_SIZE, 591 }; 592 593 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, 594 u64, flags) 595 { 596 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 597 598 /* 599 * Same comment as in bpf_perf_event_output_tp(), only that this time 600 * the other helper's function body cannot be inlined due to being 601 * external, thus we need to call raw helper function. 602 */ 603 return bpf_get_stackid((unsigned long) regs, (unsigned long) map, 604 flags, 0, 0); 605 } 606 607 static const struct bpf_func_proto bpf_get_stackid_proto_tp = { 608 .func = bpf_get_stackid_tp, 609 .gpl_only = true, 610 .ret_type = RET_INTEGER, 611 .arg1_type = ARG_PTR_TO_CTX, 612 .arg2_type = ARG_CONST_MAP_PTR, 613 .arg3_type = ARG_ANYTHING, 614 }; 615 616 BPF_CALL_3(bpf_perf_prog_read_value_tp, struct bpf_perf_event_data_kern *, ctx, 617 struct bpf_perf_event_value *, buf, u32, size) 618 { 619 int err = -EINVAL; 620 621 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 622 goto clear; 623 err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, 624 &buf->running); 625 if (unlikely(err)) 626 goto clear; 627 return 0; 628 clear: 629 memset(buf, 0, size); 630 return err; 631 } 632 633 static const struct bpf_func_proto bpf_perf_prog_read_value_proto_tp = { 634 .func = bpf_perf_prog_read_value_tp, 635 .gpl_only = true, 636 .ret_type = RET_INTEGER, 637 .arg1_type = ARG_PTR_TO_CTX, 638 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 639 .arg3_type = ARG_CONST_SIZE, 640 }; 641 642 static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id) 643 { 644 switch (func_id) { 645 case BPF_FUNC_perf_event_output: 646 return &bpf_perf_event_output_proto_tp; 647 case BPF_FUNC_get_stackid: 648 return &bpf_get_stackid_proto_tp; 649 case BPF_FUNC_perf_prog_read_value: 650 return &bpf_perf_prog_read_value_proto_tp; 651 default: 652 return tracing_func_proto(func_id); 653 } 654 } 655 656 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, 657 struct bpf_insn_access_aux *info) 658 { 659 if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) 660 return false; 661 if (type != BPF_READ) 662 return false; 663 if (off % size != 0) 664 return false; 665 666 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); 667 return true; 668 } 669 670 const struct bpf_verifier_ops tracepoint_prog_ops = { 671 .get_func_proto = tp_prog_func_proto, 672 .is_valid_access = tp_prog_is_valid_access, 673 }; 674 675 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 676 struct bpf_insn_access_aux *info) 677 { 678 const int size_sp = FIELD_SIZEOF(struct bpf_perf_event_data, 679 sample_period); 680 681 if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) 682 return false; 683 if (type != BPF_READ) 684 return false; 685 if (off % size != 0) 686 return false; 687 688 switch (off) { 689 case bpf_ctx_range(struct bpf_perf_event_data, sample_period): 690 bpf_ctx_record_field_size(info, size_sp); 691 if (!bpf_ctx_narrow_access_ok(off, size, size_sp)) 692 return false; 693 break; 694 default: 695 if (size != sizeof(long)) 696 return false; 697 } 698 699 return true; 700 } 701 702 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, 703 const struct bpf_insn *si, 704 struct bpf_insn *insn_buf, 705 struct bpf_prog *prog, u32 *target_size) 706 { 707 struct bpf_insn *insn = insn_buf; 708 709 switch (si->off) { 710 case offsetof(struct bpf_perf_event_data, sample_period): 711 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 712 data), si->dst_reg, si->src_reg, 713 offsetof(struct bpf_perf_event_data_kern, data)); 714 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 715 bpf_target_off(struct perf_sample_data, period, 8, 716 target_size)); 717 break; 718 default: 719 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 720 regs), si->dst_reg, si->src_reg, 721 offsetof(struct bpf_perf_event_data_kern, regs)); 722 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, 723 si->off); 724 break; 725 } 726 727 return insn - insn_buf; 728 } 729 730 const struct bpf_verifier_ops perf_event_prog_ops = { 731 .get_func_proto = tp_prog_func_proto, 732 .is_valid_access = pe_prog_is_valid_access, 733 .convert_ctx_access = pe_prog_convert_ctx_access, 734 }; 735