kernel/trace/bpf_trace.c

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