kernel/trace/bpf_trace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com
   3  * Copyright (c) 2016 Facebook
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/types.h>
   7 #include <linux/slab.h>
   8 #include <linux/bpf.h>
   9 #include <linux/bpf_perf_event.h>
  10 #include <linux/filter.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/ctype.h>
  13 #include <linux/kprobes.h>
  14 #include <linux/syscalls.h>
  15 #include <linux/error-injection.h>
  16
  17 #include <asm/tlb.h>
  18
  19 #include "trace_probe.h"
  20 #include "trace.h"
  21
  22 #define bpf_event_rcu_dereference(p)                                    \
  23         rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex))
  24
  25 #ifdef CONFIG_MODULES
  26 struct bpf_trace_module {
  27         struct module *module;
  28         struct list_head list;
  29 };
  30
  31 static LIST_HEAD(bpf_trace_modules);
  32 static DEFINE_MUTEX(bpf_module_mutex);
  33
  34 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name)
  35 {
  36         struct bpf_raw_event_map *btp, *ret = NULL;
  37         struct bpf_trace_module *btm;
  38         unsigned int i;
  39
  40         mutex_lock(&bpf_module_mutex);
  41         list_for_each_entry(btm, &bpf_trace_modules, list) {
  42                 for (i = 0; i < btm->module->num_bpf_raw_events; ++i) {
  43                         btp = &btm->module->bpf_raw_events[i];
  44                         if (!strcmp(btp->tp->name, name)) {
  45                                 if (try_module_get(btm->module))
  46                                         ret = btp;
  47                                 goto out;
  48                         }
  49                 }
  50         }
  51 out:
  52         mutex_unlock(&bpf_module_mutex);
  53         return ret;
  54 }
  55 #else
  56 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name)
  57 {
  58         return NULL;
  59 }
  60 #endif /* CONFIG_MODULES */
  61
  62 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  63 u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  64
  65 /**
  66  * trace_call_bpf - invoke BPF program
  67  * @call: tracepoint event
  68  * @ctx: opaque context pointer
  69  *
  70  * kprobe handlers execute BPF programs via this helper.
  71  * Can be used from static tracepoints in the future.
  72  *
  73  * Return: BPF programs always return an integer which is interpreted by
  74  * kprobe handler as:
  75  * 0 - return from kprobe (event is filtered out)
  76  * 1 - store kprobe event into ring buffer
  77  * Other values are reserved and currently alias to 1
  78  */
  79 unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
  80 {
  81         unsigned int ret;
  82
  83         if (in_nmi()) /* not supported yet */
  84                 return 1;
  85
  86         cant_sleep();
  87
  88         if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
  89                 /*
  90                  * since some bpf program is already running on this cpu,
  91                  * don't call into another bpf program (same or different)
  92                  * and don't send kprobe event into ring-buffer,
  93                  * so return zero here
  94                  */
  95                 ret = 0;
  96                 goto out;
  97         }
  98
  99         /*
 100          * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock
 101          * to all call sites, we did a bpf_prog_array_valid() there to check
 102          * whether call->prog_array is empty or not, which is
 103          * a heurisitc to speed up execution.
 104          *
 105          * If bpf_prog_array_valid() fetched prog_array was
 106          * non-NULL, we go into trace_call_bpf() and do the actual
 107          * proper rcu_dereference() under RCU lock.
 108          * If it turns out that prog_array is NULL then, we bail out.
 109          * For the opposite, if the bpf_prog_array_valid() fetched pointer
 110          * was NULL, you'll skip the prog_array with the risk of missing
 111          * out of events when it was updated in between this and the
 112          * rcu_dereference() which is accepted risk.
 113          */
 114         ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN);
 115
 116  out:
 117         __this_cpu_dec(bpf_prog_active);
 118
 119         return ret;
 120 }
 121
 122 #ifdef CONFIG_BPF_KPROBE_OVERRIDE
 123 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc)
 124 {
 125         regs_set_return_value(regs, rc);
 126         override_function_with_return(regs);
 127         return 0;
 128 }
 129
 130 static const struct bpf_func_proto bpf_override_return_proto = {
 131         .func           = bpf_override_return,
 132         .gpl_only       = true,
 133         .ret_type       = RET_INTEGER,
 134         .arg1_type      = ARG_PTR_TO_CTX,
 135         .arg2_type      = ARG_ANYTHING,
 136 };
 137 #endif
 138
 139 static __always_inline int
 140 bpf_probe_read_user_common(void *dst, u32 size, const void __user *unsafe_ptr)
 141 {
 142         int ret;
 143
 144         ret = probe_user_read(dst, unsafe_ptr, size);
 145         if (unlikely(ret < 0))
 146                 memset(dst, 0, size);
 147         return ret;
 148 }
 149
 150 BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size,
 151            const void __user *, unsafe_ptr)
 152 {
 153         return bpf_probe_read_user_common(dst, size, unsafe_ptr);
 154 }
 155
 156 const struct bpf_func_proto bpf_probe_read_user_proto = {
 157         .func           = bpf_probe_read_user,
 158         .gpl_only       = true,
 159         .ret_type       = RET_INTEGER,
 160         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 161         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 162         .arg3_type      = ARG_ANYTHING,
 163 };
 164
 165 static __always_inline int
 166 bpf_probe_read_user_str_common(void *dst, u32 size,
 167                                const void __user *unsafe_ptr)
 168 {
 169         int ret;
 170
 171         ret = strncpy_from_user_nofault(dst, unsafe_ptr, size);
 172         if (unlikely(ret < 0))
 173                 memset(dst, 0, size);
 174         return ret;
 175 }
 176
 177 BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size,
 178            const void __user *, unsafe_ptr)
 179 {
 180         return bpf_probe_read_user_str_common(dst, size, unsafe_ptr);
 181 }
 182
 183 const struct bpf_func_proto bpf_probe_read_user_str_proto = {
 184         .func           = bpf_probe_read_user_str,
 185         .gpl_only       = true,
 186         .ret_type       = RET_INTEGER,
 187         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 188         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 189         .arg3_type      = ARG_ANYTHING,
 190 };
 191
 192 static __always_inline int
 193 bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr)
 194 {
 195         int ret = security_locked_down(LOCKDOWN_BPF_READ);
 196
 197         if (unlikely(ret < 0))
 198                 goto fail;
 199         ret = probe_kernel_read(dst, unsafe_ptr, size);
 200         if (unlikely(ret < 0))
 201                 goto fail;
 202         return ret;
 203 fail:
 204         memset(dst, 0, size);
 205         return ret;
 206 }
 207
 208 BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size,
 209            const void *, unsafe_ptr)
 210 {
 211         return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);
 212 }
 213
 214 const struct bpf_func_proto bpf_probe_read_kernel_proto = {
 215         .func           = bpf_probe_read_kernel,
 216         .gpl_only       = true,
 217         .ret_type       = RET_INTEGER,
 218         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 219         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 220         .arg3_type      = ARG_ANYTHING,
 221 };
 222
 223 static __always_inline int
 224 bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr)
 225 {
 226         int ret = security_locked_down(LOCKDOWN_BPF_READ);
 227
 228         if (unlikely(ret < 0))
 229                 goto fail;
 230
 231         /*
 232          * The strncpy_from_kernel_nofault() call will likely not fill the
 233          * entire buffer, but that's okay in this circumstance as we're probing
 234          * arbitrary memory anyway similar to bpf_probe_read_*() and might
 235          * as well probe the stack. Thus, memory is explicitly cleared
 236          * only in error case, so that improper users ignoring return
 237          * code altogether don't copy garbage; otherwise length of string
 238          * is returned that can be used for bpf_perf_event_output() et al.
 239          */
 240         ret = strncpy_from_kernel_nofault(dst, unsafe_ptr, size);
 241         if (unlikely(ret < 0))
 242                 goto fail;
 243
 244         return ret;
 245 fail:
 246         memset(dst, 0, size);
 247         return ret;
 248 }
 249
 250 BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size,
 251            const void *, unsafe_ptr)
 252 {
 253         return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);
 254 }
 255
 256 const struct bpf_func_proto bpf_probe_read_kernel_str_proto = {
 257         .func           = bpf_probe_read_kernel_str,
 258         .gpl_only       = true,
 259         .ret_type       = RET_INTEGER,
 260         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 261         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 262         .arg3_type      = ARG_ANYTHING,
 263 };
 264
 265 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 266 BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size,
 267            const void *, unsafe_ptr)
 268 {
 269         if ((unsigned long)unsafe_ptr < TASK_SIZE) {
 270                 return bpf_probe_read_user_common(dst, size,
 271                                 (__force void __user *)unsafe_ptr);
 272         }
 273         return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);
 274 }
 275
 276 static const struct bpf_func_proto bpf_probe_read_compat_proto = {
 277         .func           = bpf_probe_read_compat,
 278         .gpl_only       = true,
 279         .ret_type       = RET_INTEGER,
 280         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 281         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 282         .arg3_type      = ARG_ANYTHING,
 283 };
 284
 285 BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size,
 286            const void *, unsafe_ptr)
 287 {
 288         if ((unsigned long)unsafe_ptr < TASK_SIZE) {
 289                 return bpf_probe_read_user_str_common(dst, size,
 290                                 (__force void __user *)unsafe_ptr);
 291         }
 292         return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);
 293 }
 294
 295 static const struct bpf_func_proto bpf_probe_read_compat_str_proto = {
 296         .func           = bpf_probe_read_compat_str,
 297         .gpl_only       = true,
 298         .ret_type       = RET_INTEGER,
 299         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 300         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 301         .arg3_type      = ARG_ANYTHING,
 302 };
 303 #endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
 304
 305 BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src,
 306            u32, size)
 307 {
 308         /*
 309          * Ensure we're in user context which is safe for the helper to
 310          * run. This helper has no business in a kthread.
 311          *
 312          * access_ok() should prevent writing to non-user memory, but in
 313          * some situations (nommu, temporary switch, etc) access_ok() does
 314          * not provide enough validation, hence the check on KERNEL_DS.
 315          *
 316          * nmi_uaccess_okay() ensures the probe is not run in an interim
 317          * state, when the task or mm are switched. This is specifically
 318          * required to prevent the use of temporary mm.
 319          */
 320
 321         if (unlikely(in_interrupt() ||
 322                      current->flags & (PF_KTHREAD | PF_EXITING)))
 323                 return -EPERM;
 324         if (unlikely(uaccess_kernel()))
 325                 return -EPERM;
 326         if (unlikely(!nmi_uaccess_okay()))
 327                 return -EPERM;
 328
 329         return probe_user_write(unsafe_ptr, src, size);
 330 }
 331
 332 static const struct bpf_func_proto bpf_probe_write_user_proto = {
 333         .func           = bpf_probe_write_user,
 334         .gpl_only       = true,
 335         .ret_type       = RET_INTEGER,
 336         .arg1_type      = ARG_ANYTHING,
 337         .arg2_type      = ARG_PTR_TO_MEM,
 338         .arg3_type      = ARG_CONST_SIZE,
 339 };
 340
 341 static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
 342 {
 343         if (!capable(CAP_SYS_ADMIN))
 344                 return NULL;
 345
 346         pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",
 347                             current->comm, task_pid_nr(current));
 348
 349         return &bpf_probe_write_user_proto;
 350 }
 351
 352 static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
 353                 size_t bufsz)
 354 {
 355         void __user *user_ptr = (__force void __user *)unsafe_ptr;
 356
 357         buf[0] = 0;
 358
 359         switch (fmt_ptype) {
 360         case 's':
 361 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 362                 if ((unsigned long)unsafe_ptr < TASK_SIZE) {
 363                         strncpy_from_user_nofault(buf, user_ptr, bufsz);
 364                         break;
 365                 }
 366                 fallthrough;
 367 #endif
 368         case 'k':
 369                 strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
 370                 break;
 371         case 'u':
 372                 strncpy_from_user_nofault(buf, user_ptr, bufsz);
 373                 break;
 374         }
 375 }
 376
 377 /*
 378  * Only limited trace_printk() conversion specifiers allowed:
 379  * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s
 380  */
 381 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
 382            u64, arg2, u64, arg3)
 383 {
 384         int i, mod[3] = {}, fmt_cnt = 0;
 385         char buf[64], fmt_ptype;
 386         void *unsafe_ptr = NULL;
 387         bool str_seen = false;
 388
 389         /*
 390          * bpf_check()->check_func_arg()->check_stack_boundary()
 391          * guarantees that fmt points to bpf program stack,
 392          * fmt_size bytes of it were initialized and fmt_size > 0
 393          */
 394         if (fmt[--fmt_size] != 0)
 395                 return -EINVAL;
 396
 397         /* check format string for allowed specifiers */
 398         for (i = 0; i < fmt_size; i++) {
 399                 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))
 400                         return -EINVAL;
 401
 402                 if (fmt[i] != '%')
 403                         continue;
 404
 405                 if (fmt_cnt >= 3)
 406                         return -EINVAL;
 407
 408                 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
 409                 i++;
 410                 if (fmt[i] == 'l') {
 411                         mod[fmt_cnt]++;
 412                         i++;
 413                 } else if (fmt[i] == 'p') {
 414                         mod[fmt_cnt]++;
 415                         if ((fmt[i + 1] == 'k' ||
 416                              fmt[i + 1] == 'u') &&
 417                             fmt[i + 2] == 's') {
 418                                 fmt_ptype = fmt[i + 1];
 419                                 i += 2;
 420                                 goto fmt_str;
 421                         }
 422
 423                         if (fmt[i + 1] == 'B') {
 424                                 i++;
 425                                 goto fmt_next;
 426                         }
 427
 428                         /* disallow any further format extensions */
 429                         if (fmt[i + 1] != 0 &&
 430                             !isspace(fmt[i + 1]) &&
 431                             !ispunct(fmt[i + 1]))
 432                                 return -EINVAL;
 433
 434                         goto fmt_next;
 435                 } else if (fmt[i] == 's') {
 436                         mod[fmt_cnt]++;
 437                         fmt_ptype = fmt[i];
 438 fmt_str:
 439                         if (str_seen)
 440                                 /* allow only one '%s' per fmt string */
 441                                 return -EINVAL;
 442                         str_seen = true;
 443
 444                         if (fmt[i + 1] != 0 &&
 445                             !isspace(fmt[i + 1]) &&
 446                             !ispunct(fmt[i + 1]))
 447                                 return -EINVAL;
 448
 449                         switch (fmt_cnt) {
 450                         case 0:
 451                                 unsafe_ptr = (void *)(long)arg1;
 452                                 arg1 = (long)buf;
 453                                 break;
 454                         case 1:
 455                                 unsafe_ptr = (void *)(long)arg2;
 456                                 arg2 = (long)buf;
 457                                 break;
 458                         case 2:
 459                                 unsafe_ptr = (void *)(long)arg3;
 460                                 arg3 = (long)buf;
 461                                 break;
 462                         }
 463
 464                         bpf_trace_copy_string(buf, unsafe_ptr, fmt_ptype,
 465                                         sizeof(buf));
 466                         goto fmt_next;
 467                 }
 468
 469                 if (fmt[i] == 'l') {
 470                         mod[fmt_cnt]++;
 471                         i++;
 472                 }
 473
 474                 if (fmt[i] != 'i' && fmt[i] != 'd' &&
 475                     fmt[i] != 'u' && fmt[i] != 'x')
 476                         return -EINVAL;
 477 fmt_next:
 478                 fmt_cnt++;
 479         }
 480
 481 /* Horrid workaround for getting va_list handling working with different
 482  * argument type combinations generically for 32 and 64 bit archs.
 483  */
 484 #define __BPF_TP_EMIT() __BPF_ARG3_TP()
 485 #define __BPF_TP(...)                                                   \
 486         __trace_printk(0 /* Fake ip */,                                 \
 487                        fmt, ##__VA_ARGS__)
 488
 489 #define __BPF_ARG1_TP(...)                                              \
 490         ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64))        \
 491           ? __BPF_TP(arg1, ##__VA_ARGS__)                               \
 492           : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32))    \
 493               ? __BPF_TP((long)arg1, ##__VA_ARGS__)                     \
 494               : __BPF_TP((u32)arg1, ##__VA_ARGS__)))
 495
 496 #define __BPF_ARG2_TP(...)                                              \
 497         ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64))        \
 498           ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__)                          \
 499           : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32))    \
 500               ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__)                \
 501               : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__)))
 502
 503 #define __BPF_ARG3_TP(...)                                              \
 504         ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64))        \
 505           ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__)                          \
 506           : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32))    \
 507               ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__)                \
 508               : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__)))
 509
 510         return __BPF_TP_EMIT();
 511 }
 512
 513 static const struct bpf_func_proto bpf_trace_printk_proto = {
 514         .func           = bpf_trace_printk,
 515         .gpl_only       = true,
 516         .ret_type       = RET_INTEGER,
 517         .arg1_type      = ARG_PTR_TO_MEM,
 518         .arg2_type      = ARG_CONST_SIZE,
 519 };
 520
 521 const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
 522 {
 523         /*
 524          * this program might be calling bpf_trace_printk,
 525          * so allocate per-cpu printk buffers
 526          */
 527         trace_printk_init_buffers();
 528
 529         return &bpf_trace_printk_proto;
 530 }
 531
 532 #define MAX_SEQ_PRINTF_VARARGS          12
 533 #define MAX_SEQ_PRINTF_MAX_MEMCPY       6
 534 #define MAX_SEQ_PRINTF_STR_LEN          128
 535
 536 struct bpf_seq_printf_buf {
 537         char buf[MAX_SEQ_PRINTF_MAX_MEMCPY][MAX_SEQ_PRINTF_STR_LEN];
 538 };
 539 static DEFINE_PER_CPU(struct bpf_seq_printf_buf, bpf_seq_printf_buf);
 540 static DEFINE_PER_CPU(int, bpf_seq_printf_buf_used);
 541
 542 BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size,
 543            const void *, data, u32, data_len)
 544 {
 545         int err = -EINVAL, fmt_cnt = 0, memcpy_cnt = 0;
 546         int i, buf_used, copy_size, num_args;
 547         u64 params[MAX_SEQ_PRINTF_VARARGS];
 548         struct bpf_seq_printf_buf *bufs;
 549         const u64 *args = data;
 550
 551         buf_used = this_cpu_inc_return(bpf_seq_printf_buf_used);
 552         if (WARN_ON_ONCE(buf_used > 1)) {
 553                 err = -EBUSY;
 554                 goto out;
 555         }
 556
 557         bufs = this_cpu_ptr(&bpf_seq_printf_buf);
 558
 559         /*
 560          * bpf_check()->check_func_arg()->check_stack_boundary()
 561          * guarantees that fmt points to bpf program stack,
 562          * fmt_size bytes of it were initialized and fmt_size > 0
 563          */
 564         if (fmt[--fmt_size] != 0)
 565                 goto out;
 566
 567         if (data_len & 7)
 568                 goto out;
 569
 570         for (i = 0; i < fmt_size; i++) {
 571                 if (fmt[i] == '%') {
 572                         if (fmt[i + 1] == '%')
 573                                 i++;
 574                         else if (!data || !data_len)
 575                                 goto out;
 576                 }
 577         }
 578
 579         num_args = data_len / 8;
 580
 581         /* check format string for allowed specifiers */
 582         for (i = 0; i < fmt_size; i++) {
 583                 /* only printable ascii for now. */
 584                 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
 585                         err = -EINVAL;
 586                         goto out;
 587                 }
 588
 589                 if (fmt[i] != '%')
 590                         continue;
 591
 592                 if (fmt[i + 1] == '%') {
 593                         i++;
 594                         continue;
 595                 }
 596
 597                 if (fmt_cnt >= MAX_SEQ_PRINTF_VARARGS) {
 598                         err = -E2BIG;
 599                         goto out;
 600                 }
 601
 602                 if (fmt_cnt >= num_args) {
 603                         err = -EINVAL;
 604                         goto out;
 605                 }
 606
 607                 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
 608                 i++;
 609
 610                 /* skip optional "[0 +-][num]" width formating field */
 611                 while (fmt[i] == '0' || fmt[i] == '+'  || fmt[i] == '-' ||
 612                        fmt[i] == ' ')
 613                         i++;
 614                 if (fmt[i] >= '1' && fmt[i] <= '9') {
 615                         i++;
 616                         while (fmt[i] >= '0' && fmt[i] <= '9')
 617                                 i++;
 618                 }
 619
 620                 if (fmt[i] == 's') {
 621                         void *unsafe_ptr;
 622
 623                         /* try our best to copy */
 624                         if (memcpy_cnt >= MAX_SEQ_PRINTF_MAX_MEMCPY) {
 625                                 err = -E2BIG;
 626                                 goto out;
 627                         }
 628
 629                         unsafe_ptr = (void *)(long)args[fmt_cnt];
 630                         err = strncpy_from_kernel_nofault(bufs->buf[memcpy_cnt],
 631                                         unsafe_ptr, MAX_SEQ_PRINTF_STR_LEN);
 632                         if (err < 0)
 633                                 bufs->buf[memcpy_cnt][0] = '\0';
 634                         params[fmt_cnt] = (u64)(long)bufs->buf[memcpy_cnt];
 635
 636                         fmt_cnt++;
 637                         memcpy_cnt++;
 638                         continue;
 639                 }
 640
 641                 if (fmt[i] == 'p') {
 642                         if (fmt[i + 1] == 0 ||
 643                             fmt[i + 1] == 'K' ||
 644                             fmt[i + 1] == 'x' ||
 645                             fmt[i + 1] == 'B') {
 646                                 /* just kernel pointers */
 647                                 params[fmt_cnt] = args[fmt_cnt];
 648                                 fmt_cnt++;
 649                                 continue;
 650                         }
 651
 652                         /* only support "%pI4", "%pi4", "%pI6" and "%pi6". */
 653                         if (fmt[i + 1] != 'i' && fmt[i + 1] != 'I') {
 654                                 err = -EINVAL;
 655                                 goto out;
 656                         }
 657                         if (fmt[i + 2] != '4' && fmt[i + 2] != '6') {
 658                                 err = -EINVAL;
 659                                 goto out;
 660                         }
 661
 662                         if (memcpy_cnt >= MAX_SEQ_PRINTF_MAX_MEMCPY) {
 663                                 err = -E2BIG;
 664                                 goto out;
 665                         }
 666
 667
 668                         copy_size = (fmt[i + 2] == '4') ? 4 : 16;
 669
 670                         err = probe_kernel_read(bufs->buf[memcpy_cnt],
 671                                                 (void *) (long) args[fmt_cnt],
 672                                                 copy_size);
 673                         if (err < 0)
 674                                 memset(bufs->buf[memcpy_cnt], 0, copy_size);
 675                         params[fmt_cnt] = (u64)(long)bufs->buf[memcpy_cnt];
 676
 677                         i += 2;
 678                         fmt_cnt++;
 679                         memcpy_cnt++;
 680                         continue;
 681                 }
 682
 683                 if (fmt[i] == 'l') {
 684                         i++;
 685                         if (fmt[i] == 'l')
 686                                 i++;
 687                 }
 688
 689                 if (fmt[i] != 'i' && fmt[i] != 'd' &&
 690                     fmt[i] != 'u' && fmt[i] != 'x' &&
 691                     fmt[i] != 'X') {
 692                         err = -EINVAL;
 693                         goto out;
 694                 }
 695
 696                 params[fmt_cnt] = args[fmt_cnt];
 697                 fmt_cnt++;
 698         }
 699
 700         /* Maximumly we can have MAX_SEQ_PRINTF_VARARGS parameter, just give
 701          * all of them to seq_printf().
 702          */
 703         seq_printf(m, fmt, params[0], params[1], params[2], params[3],
 704                    params[4], params[5], params[6], params[7], params[8],
 705                    params[9], params[10], params[11]);
 706
 707         err = seq_has_overflowed(m) ? -EOVERFLOW : 0;
 708 out:
 709         this_cpu_dec(bpf_seq_printf_buf_used);
 710         return err;
 711 }
 712
 713 static int bpf_seq_printf_btf_ids[5];
 714 static const struct bpf_func_proto bpf_seq_printf_proto = {
 715         .func           = bpf_seq_printf,
 716         .gpl_only       = true,
 717         .ret_type       = RET_INTEGER,
 718         .arg1_type      = ARG_PTR_TO_BTF_ID,
 719         .arg2_type      = ARG_PTR_TO_MEM,
 720         .arg3_type      = ARG_CONST_SIZE,
 721         .arg4_type      = ARG_PTR_TO_MEM_OR_NULL,
 722         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 723         .btf_id         = bpf_seq_printf_btf_ids,
 724 };
 725
 726 BPF_CALL_3(bpf_seq_write, struct seq_file *, m, const void *, data, u32, len)
 727 {
 728         return seq_write(m, data, len) ? -EOVERFLOW : 0;
 729 }
 730
 731 static int bpf_seq_write_btf_ids[5];
 732 static const struct bpf_func_proto bpf_seq_write_proto = {
 733         .func           = bpf_seq_write,
 734         .gpl_only       = true,
 735         .ret_type       = RET_INTEGER,
 736         .arg1_type      = ARG_PTR_TO_BTF_ID,
 737         .arg2_type      = ARG_PTR_TO_MEM,
 738         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
 739         .btf_id         = bpf_seq_write_btf_ids,
 740 };
 741
 742 static __always_inline int
 743 get_map_perf_counter(struct bpf_map *map, u64 flags,
 744                      u64 *value, u64 *enabled, u64 *running)
 745 {
 746         struct bpf_array *array = container_of(map, struct bpf_array, map);
 747         unsigned int cpu = smp_processor_id();
 748         u64 index = flags & BPF_F_INDEX_MASK;
 749         struct bpf_event_entry *ee;
 750
 751         if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
 752                 return -EINVAL;
 753         if (index == BPF_F_CURRENT_CPU)
 754                 index = cpu;
 755         if (unlikely(index >= array->map.max_entries))
 756                 return -E2BIG;
 757
 758         ee = READ_ONCE(array->ptrs[index]);
 759         if (!ee)
 760                 return -ENOENT;
 761
 762         return perf_event_read_local(ee->event, value, enabled, running);
 763 }
 764
 765 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
 766 {
 767         u64 value = 0;
 768         int err;
 769
 770         err = get_map_perf_counter(map, flags, &value, NULL, NULL);
 771         /*
 772          * this api is ugly since we miss [-22..-2] range of valid
 773          * counter values, but that's uapi
 774          */
 775         if (err)
 776                 return err;
 777         return value;
 778 }
 779
 780 static const struct bpf_func_proto bpf_perf_event_read_proto = {
 781         .func           = bpf_perf_event_read,
 782         .gpl_only       = true,
 783         .ret_type       = RET_INTEGER,
 784         .arg1_type      = ARG_CONST_MAP_PTR,
 785         .arg2_type      = ARG_ANYTHING,
 786 };
 787
 788 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags,
 789            struct bpf_perf_event_value *, buf, u32, size)
 790 {
 791         int err = -EINVAL;
 792
 793         if (unlikely(size != sizeof(struct bpf_perf_event_value)))
 794                 goto clear;
 795         err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled,
 796                                    &buf->running);
 797         if (unlikely(err))
 798                 goto clear;
 799         return 0;
 800 clear:
 801         memset(buf, 0, size);
 802         return err;
 803 }
 804
 805 static const struct bpf_func_proto bpf_perf_event_read_value_proto = {
 806         .func           = bpf_perf_event_read_value,
 807         .gpl_only       = true,
 808         .ret_type       = RET_INTEGER,
 809         .arg1_type      = ARG_CONST_MAP_PTR,
 810         .arg2_type      = ARG_ANYTHING,
 811         .arg3_type      = ARG_PTR_TO_UNINIT_MEM,
 812         .arg4_type      = ARG_CONST_SIZE,
 813 };
 814
 815 static __always_inline u64
 816 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
 817                         u64 flags, struct perf_sample_data *sd)
 818 {
 819         struct bpf_array *array = container_of(map, struct bpf_array, map);
 820         unsigned int cpu = smp_processor_id();
 821         u64 index = flags & BPF_F_INDEX_MASK;
 822         struct bpf_event_entry *ee;
 823         struct perf_event *event;
 824
 825         if (index == BPF_F_CURRENT_CPU)
 826                 index = cpu;
 827         if (unlikely(index >= array->map.max_entries))
 828                 return -E2BIG;
 829
 830         ee = READ_ONCE(array->ptrs[index]);
 831         if (!ee)
 832                 return -ENOENT;
 833
 834         event = ee->event;
 835         if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
 836                      event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
 837                 return -EINVAL;
 838
 839         if (unlikely(event->oncpu != cpu))
 840                 return -EOPNOTSUPP;
 841
 842         return perf_event_output(event, sd, regs);
 843 }
 844
 845 /*
 846  * Support executing tracepoints in normal, irq, and nmi context that each call
 847  * bpf_perf_event_output
 848  */
 849 struct bpf_trace_sample_data {
 850         struct perf_sample_data sds[3];
 851 };
 852
 853 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds);
 854 static DEFINE_PER_CPU(int, bpf_trace_nest_level);
 855 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
 856            u64, flags, void *, data, u64, size)
 857 {
 858         struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds);
 859         int nest_level = this_cpu_inc_return(bpf_trace_nest_level);
 860         struct perf_raw_record raw = {
 861                 .frag = {
 862                         .size = size,
 863                         .data = data,
 864                 },
 865         };
 866         struct perf_sample_data *sd;
 867         int err;
 868
 869         if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) {
 870                 err = -EBUSY;
 871                 goto out;
 872         }
 873
 874         sd = &sds->sds[nest_level - 1];
 875
 876         if (unlikely(flags & ~(BPF_F_INDEX_MASK))) {
 877                 err = -EINVAL;
 878                 goto out;
 879         }
 880
 881         perf_sample_data_init(sd, 0, 0);
 882         sd->raw = &raw;
 883
 884         err = __bpf_perf_event_output(regs, map, flags, sd);
 885
 886 out:
 887         this_cpu_dec(bpf_trace_nest_level);
 888         return err;
 889 }
 890
 891 static const struct bpf_func_proto bpf_perf_event_output_proto = {
 892         .func           = bpf_perf_event_output,
 893         .gpl_only       = true,
 894         .ret_type       = RET_INTEGER,
 895         .arg1_type      = ARG_PTR_TO_CTX,
 896         .arg2_type      = ARG_CONST_MAP_PTR,
 897         .arg3_type      = ARG_ANYTHING,
 898         .arg4_type      = ARG_PTR_TO_MEM,
 899         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 900 };
 901
 902 static DEFINE_PER_CPU(int, bpf_event_output_nest_level);
 903 struct bpf_nested_pt_regs {
 904         struct pt_regs regs[3];
 905 };
 906 static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs);
 907 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds);
 908
 909 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
 910                      void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
 911 {
 912         int nest_level = this_cpu_inc_return(bpf_event_output_nest_level);
 913         struct perf_raw_frag frag = {
 914                 .copy           = ctx_copy,
 915                 .size           = ctx_size,
 916                 .data           = ctx,
 917         };
 918         struct perf_raw_record raw = {
 919                 .frag = {
 920                         {
 921                                 .next   = ctx_size ? &frag : NULL,
 922                         },
 923                         .size   = meta_size,
 924                         .data   = meta,
 925                 },
 926         };
 927         struct perf_sample_data *sd;
 928         struct pt_regs *regs;
 929         u64 ret;
 930
 931         if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) {
 932                 ret = -EBUSY;
 933                 goto out;
 934         }
 935         sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]);
 936         regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]);
 937
 938         perf_fetch_caller_regs(regs);
 939         perf_sample_data_init(sd, 0, 0);
 940         sd->raw = &raw;
 941
 942         ret = __bpf_perf_event_output(regs, map, flags, sd);
 943 out:
 944         this_cpu_dec(bpf_event_output_nest_level);
 945         return ret;
 946 }
 947
 948 BPF_CALL_0(bpf_get_current_task)
 949 {
 950         return (long) current;
 951 }
 952
 953 const struct bpf_func_proto bpf_get_current_task_proto = {
 954         .func           = bpf_get_current_task,
 955         .gpl_only       = true,
 956         .ret_type       = RET_INTEGER,
 957 };
 958
 959 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx)
 960 {
 961         struct bpf_array *array = container_of(map, struct bpf_array, map);
 962         struct cgroup *cgrp;
 963
 964         if (unlikely(idx >= array->map.max_entries))
 965                 return -E2BIG;
 966
 967         cgrp = READ_ONCE(array->ptrs[idx]);
 968         if (unlikely(!cgrp))
 969                 return -EAGAIN;
 970
 971         return task_under_cgroup_hierarchy(current, cgrp);
 972 }
 973
 974 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = {
 975         .func           = bpf_current_task_under_cgroup,
 976         .gpl_only       = false,
 977         .ret_type       = RET_INTEGER,
 978         .arg1_type      = ARG_CONST_MAP_PTR,
 979         .arg2_type      = ARG_ANYTHING,
 980 };
 981
 982 struct send_signal_irq_work {
 983         struct irq_work irq_work;
 984         struct task_struct *task;
 985         u32 sig;
 986         enum pid_type type;
 987 };
 988
 989 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work);
 990
 991 static void do_bpf_send_signal(struct irq_work *entry)
 992 {
 993         struct send_signal_irq_work *work;
 994
 995         work = container_of(entry, struct send_signal_irq_work, irq_work);
 996         group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type);
 997 }
 998
 999 static int bpf_send_signal_common(u32 sig, enum pid_type type)
1000 {
1001         struct send_signal_irq_work *work = NULL;
1002
1003         /* Similar to bpf_probe_write_user, task needs to be
1004          * in a sound condition and kernel memory access be
1005          * permitted in order to send signal to the current
1006          * task.
1007          */
1008         if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING)))
1009                 return -EPERM;
1010         if (unlikely(uaccess_kernel()))
1011                 return -EPERM;
1012         if (unlikely(!nmi_uaccess_okay()))
1013                 return -EPERM;
1014
1015         if (irqs_disabled()) {
1016                 /* Do an early check on signal validity. Otherwise,
1017                  * the error is lost in deferred irq_work.
1018                  */
1019                 if (unlikely(!valid_signal(sig)))
1020                         return -EINVAL;
1021
1022                 work = this_cpu_ptr(&send_signal_work);
1023                 if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY)
1024                         return -EBUSY;
1025
1026                 /* Add the current task, which is the target of sending signal,
1027                  * to the irq_work. The current task may change when queued
1028                  * irq works get executed.
1029                  */
1030                 work->task = current;
1031                 work->sig = sig;
1032                 work->type = type;
1033                 irq_work_queue(&work->irq_work);
1034                 return 0;
1035         }
1036
1037         return group_send_sig_info(sig, SEND_SIG_PRIV, current, type);
1038 }
1039
1040 BPF_CALL_1(bpf_send_signal, u32, sig)
1041 {
1042         return bpf_send_signal_common(sig, PIDTYPE_TGID);
1043 }
1044
1045 static const struct bpf_func_proto bpf_send_signal_proto = {
1046         .func           = bpf_send_signal,
1047         .gpl_only       = false,
1048         .ret_type       = RET_INTEGER,
1049         .arg1_type      = ARG_ANYTHING,
1050 };
1051
1052 BPF_CALL_1(bpf_send_signal_thread, u32, sig)
1053 {
1054         return bpf_send_signal_common(sig, PIDTYPE_PID);
1055 }
1056
1057 static const struct bpf_func_proto bpf_send_signal_thread_proto = {
1058         .func           = bpf_send_signal_thread,
1059         .gpl_only       = false,
1060         .ret_type       = RET_INTEGER,
1061         .arg1_type      = ARG_ANYTHING,
1062 };
1063
1064 const struct bpf_func_proto *
1065 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1066 {
1067         switch (func_id) {
1068         case BPF_FUNC_map_lookup_elem:
1069                 return &bpf_map_lookup_elem_proto;
1070         case BPF_FUNC_map_update_elem:
1071                 return &bpf_map_update_elem_proto;
1072         case BPF_FUNC_map_delete_elem:
1073                 return &bpf_map_delete_elem_proto;
1074         case BPF_FUNC_map_push_elem:
1075                 return &bpf_map_push_elem_proto;
1076         case BPF_FUNC_map_pop_elem:
1077                 return &bpf_map_pop_elem_proto;
1078         case BPF_FUNC_map_peek_elem:
1079                 return &bpf_map_peek_elem_proto;
1080         case BPF_FUNC_ktime_get_ns:
1081                 return &bpf_ktime_get_ns_proto;
1082         case BPF_FUNC_ktime_get_boot_ns:
1083                 return &bpf_ktime_get_boot_ns_proto;
1084         case BPF_FUNC_tail_call:
1085                 return &bpf_tail_call_proto;
1086         case BPF_FUNC_get_current_pid_tgid:
1087                 return &bpf_get_current_pid_tgid_proto;
1088         case BPF_FUNC_get_current_task:
1089                 return &bpf_get_current_task_proto;
1090         case BPF_FUNC_get_current_uid_gid:
1091                 return &bpf_get_current_uid_gid_proto;
1092         case BPF_FUNC_get_current_comm:
1093                 return &bpf_get_current_comm_proto;
1094         case BPF_FUNC_trace_printk:
1095                 return bpf_get_trace_printk_proto();
1096         case BPF_FUNC_get_smp_processor_id:
1097                 return &bpf_get_smp_processor_id_proto;
1098         case BPF_FUNC_get_numa_node_id:
1099                 return &bpf_get_numa_node_id_proto;
1100         case BPF_FUNC_perf_event_read:
1101                 return &bpf_perf_event_read_proto;
1102         case BPF_FUNC_probe_write_user:
1103                 return bpf_get_probe_write_proto();
1104         case BPF_FUNC_current_task_under_cgroup:
1105                 return &bpf_current_task_under_cgroup_proto;
1106         case BPF_FUNC_get_prandom_u32:
1107                 return &bpf_get_prandom_u32_proto;
1108         case BPF_FUNC_probe_read_user:
1109                 return &bpf_probe_read_user_proto;
1110         case BPF_FUNC_probe_read_kernel:
1111                 return &bpf_probe_read_kernel_proto;
1112         case BPF_FUNC_probe_read_user_str:
1113                 return &bpf_probe_read_user_str_proto;
1114         case BPF_FUNC_probe_read_kernel_str:
1115                 return &bpf_probe_read_kernel_str_proto;
1116 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1117         case BPF_FUNC_probe_read:
1118                 return &bpf_probe_read_compat_proto;
1119         case BPF_FUNC_probe_read_str:
1120                 return &bpf_probe_read_compat_str_proto;
1121 #endif
1122 #ifdef CONFIG_CGROUPS
1123         case BPF_FUNC_get_current_cgroup_id:
1124                 return &bpf_get_current_cgroup_id_proto;
1125 #endif
1126         case BPF_FUNC_send_signal:
1127                 return &bpf_send_signal_proto;
1128         case BPF_FUNC_send_signal_thread:
1129                 return &bpf_send_signal_thread_proto;
1130         case BPF_FUNC_perf_event_read_value:
1131                 return &bpf_perf_event_read_value_proto;
1132         case BPF_FUNC_get_ns_current_pid_tgid:
1133                 return &bpf_get_ns_current_pid_tgid_proto;
1134         case BPF_FUNC_ringbuf_output:
1135                 return &bpf_ringbuf_output_proto;
1136         case BPF_FUNC_ringbuf_reserve:
1137                 return &bpf_ringbuf_reserve_proto;
1138         case BPF_FUNC_ringbuf_submit:
1139                 return &bpf_ringbuf_submit_proto;
1140         case BPF_FUNC_ringbuf_discard:
1141                 return &bpf_ringbuf_discard_proto;
1142         case BPF_FUNC_ringbuf_query:
1143                 return &bpf_ringbuf_query_proto;
1144         case BPF_FUNC_jiffies64:
1145                 return &bpf_jiffies64_proto;
1146         case BPF_FUNC_get_task_stack:
1147                 return &bpf_get_task_stack_proto;
1148         default:
1149                 return NULL;
1150         }
1151 }
1152
1153 static const struct bpf_func_proto *
1154 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1155 {
1156         switch (func_id) {
1157         case BPF_FUNC_perf_event_output:
1158                 return &bpf_perf_event_output_proto;
1159         case BPF_FUNC_get_stackid:
1160                 return &bpf_get_stackid_proto;
1161         case BPF_FUNC_get_stack:
1162                 return &bpf_get_stack_proto;
1163 #ifdef CONFIG_BPF_KPROBE_OVERRIDE
1164         case BPF_FUNC_override_return:
1165                 return &bpf_override_return_proto;
1166 #endif
1167         default:
1168                 return bpf_tracing_func_proto(func_id, prog);
1169         }
1170 }
1171
1172 /* bpf+kprobe programs can access fields of 'struct pt_regs' */
1173 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
1174                                         const struct bpf_prog *prog,
1175                                         struct bpf_insn_access_aux *info)
1176 {
1177         if (off < 0 || off >= sizeof(struct pt_regs))
1178                 return false;
1179         if (type != BPF_READ)
1180                 return false;
1181         if (off % size != 0)
1182                 return false;
1183         /*
1184          * Assertion for 32 bit to make sure last 8 byte access
1185          * (BPF_DW) to the last 4 byte member is disallowed.
1186          */
1187         if (off + size > sizeof(struct pt_regs))
1188                 return false;
1189
1190         return true;
1191 }
1192
1193 const struct bpf_verifier_ops kprobe_verifier_ops = {
1194         .get_func_proto  = kprobe_prog_func_proto,
1195         .is_valid_access = kprobe_prog_is_valid_access,
1196 };
1197
1198 const struct bpf_prog_ops kprobe_prog_ops = {
1199 };
1200
1201 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
1202            u64, flags, void *, data, u64, size)
1203 {
1204         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
1205
1206         /*
1207          * r1 points to perf tracepoint buffer where first 8 bytes are hidden
1208          * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it
1209          * from there and call the same bpf_perf_event_output() helper inline.
1210          */
1211         return ____bpf_perf_event_output(regs, map, flags, data, size);
1212 }
1213
1214 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
1215         .func           = bpf_perf_event_output_tp,
1216         .gpl_only       = true,
1217         .ret_type       = RET_INTEGER,
1218         .arg1_type      = ARG_PTR_TO_CTX,
1219         .arg2_type      = ARG_CONST_MAP_PTR,
1220         .arg3_type      = ARG_ANYTHING,
1221         .arg4_type      = ARG_PTR_TO_MEM,
1222         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
1223 };
1224
1225 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
1226            u64, flags)
1227 {
1228         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
1229
1230         /*
1231          * Same comment as in bpf_perf_event_output_tp(), only that this time
1232          * the other helper's function body cannot be inlined due to being
1233          * external, thus we need to call raw helper function.
1234          */
1235         return bpf_get_stackid((unsigned long) regs, (unsigned long) map,
1236                                flags, 0, 0);
1237 }
1238
1239 static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
1240         .func           = bpf_get_stackid_tp,
1241         .gpl_only       = true,
1242         .ret_type       = RET_INTEGER,
1243         .arg1_type      = ARG_PTR_TO_CTX,
1244         .arg2_type      = ARG_CONST_MAP_PTR,
1245         .arg3_type      = ARG_ANYTHING,
1246 };
1247
1248 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size,
1249            u64, flags)
1250 {
1251         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
1252
1253         return bpf_get_stack((unsigned long) regs, (unsigned long) buf,
1254                              (unsigned long) size, flags, 0);
1255 }
1256
1257 static const struct bpf_func_proto bpf_get_stack_proto_tp = {
1258         .func           = bpf_get_stack_tp,
1259         .gpl_only       = true,
1260         .ret_type       = RET_INTEGER,
1261         .arg1_type      = ARG_PTR_TO_CTX,
1262         .arg2_type      = ARG_PTR_TO_UNINIT_MEM,
1263         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
1264         .arg4_type      = ARG_ANYTHING,
1265 };
1266
1267 static const struct bpf_func_proto *
1268 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1269 {
1270         switch (func_id) {
1271         case BPF_FUNC_perf_event_output:
1272                 return &bpf_perf_event_output_proto_tp;
1273         case BPF_FUNC_get_stackid:
1274                 return &bpf_get_stackid_proto_tp;
1275         case BPF_FUNC_get_stack:
1276                 return &bpf_get_stack_proto_tp;
1277         default:
1278                 return bpf_tracing_func_proto(func_id, prog);
1279         }
1280 }
1281
1282 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,
1283                                     const struct bpf_prog *prog,
1284                                     struct bpf_insn_access_aux *info)
1285 {
1286         if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
1287                 return false;
1288         if (type != BPF_READ)
1289                 return false;
1290         if (off % size != 0)
1291                 return false;
1292
1293         BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64));
1294         return true;
1295 }
1296
1297 const struct bpf_verifier_ops tracepoint_verifier_ops = {
1298         .get_func_proto  = tp_prog_func_proto,
1299         .is_valid_access = tp_prog_is_valid_access,
1300 };
1301
1302 const struct bpf_prog_ops tracepoint_prog_ops = {
1303 };
1304
1305 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx,
1306            struct bpf_perf_event_value *, buf, u32, size)
1307 {
1308         int err = -EINVAL;
1309
1310         if (unlikely(size != sizeof(struct bpf_perf_event_value)))
1311                 goto clear;
1312         err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
1313                                     &buf->running);
1314         if (unlikely(err))
1315                 goto clear;
1316         return 0;
1317 clear:
1318         memset(buf, 0, size);
1319         return err;
1320 }
1321
1322 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = {
1323          .func           = bpf_perf_prog_read_value,
1324          .gpl_only       = true,
1325          .ret_type       = RET_INTEGER,
1326          .arg1_type      = ARG_PTR_TO_CTX,
1327          .arg2_type      = ARG_PTR_TO_UNINIT_MEM,
1328          .arg3_type      = ARG_CONST_SIZE,
1329 };
1330
1331 BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx,
1332            void *, buf, u32, size, u64, flags)
1333 {
1334 #ifndef CONFIG_X86
1335         return -ENOENT;
1336 #else
1337         static const u32 br_entry_size = sizeof(struct perf_branch_entry);
1338         struct perf_branch_stack *br_stack = ctx->data->br_stack;
1339         u32 to_copy;
1340
1341         if (unlikely(flags & ~BPF_F_GET_BRANCH_RECORDS_SIZE))
1342                 return -EINVAL;
1343
1344         if (unlikely(!br_stack))
1345                 return -EINVAL;
1346
1347         if (flags & BPF_F_GET_BRANCH_RECORDS_SIZE)
1348                 return br_stack->nr * br_entry_size;
1349
1350         if (!buf || (size % br_entry_size != 0))
1351                 return -EINVAL;
1352
1353         to_copy = min_t(u32, br_stack->nr * br_entry_size, size);
1354         memcpy(buf, br_stack->entries, to_copy);
1355
1356         return to_copy;
1357 #endif
1358 }
1359
1360 static const struct bpf_func_proto bpf_read_branch_records_proto = {
1361         .func           = bpf_read_branch_records,
1362         .gpl_only       = true,
1363         .ret_type       = RET_INTEGER,
1364         .arg1_type      = ARG_PTR_TO_CTX,
1365         .arg2_type      = ARG_PTR_TO_MEM_OR_NULL,
1366         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
1367         .arg4_type      = ARG_ANYTHING,
1368 };
1369
1370 static const struct bpf_func_proto *
1371 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1372 {
1373         switch (func_id) {
1374         case BPF_FUNC_perf_event_output:
1375                 return &bpf_perf_event_output_proto_tp;
1376         case BPF_FUNC_get_stackid:
1377                 return &bpf_get_stackid_proto_tp;
1378         case BPF_FUNC_get_stack:
1379                 return &bpf_get_stack_proto_tp;
1380         case BPF_FUNC_perf_prog_read_value:
1381                 return &bpf_perf_prog_read_value_proto;
1382         case BPF_FUNC_read_branch_records:
1383                 return &bpf_read_branch_records_proto;
1384         default:
1385                 return bpf_tracing_func_proto(func_id, prog);
1386         }
1387 }
1388
1389 /*
1390  * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp
1391  * to avoid potential recursive reuse issue when/if tracepoints are added
1392  * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack.
1393  *
1394  * Since raw tracepoints run despite bpf_prog_active, support concurrent usage
1395  * in normal, irq, and nmi context.
1396  */
1397 struct bpf_raw_tp_regs {
1398         struct pt_regs regs[3];
1399 };
1400 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs);
1401 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level);
1402 static struct pt_regs *get_bpf_raw_tp_regs(void)
1403 {
1404         struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs);
1405         int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level);
1406
1407         if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) {
1408                 this_cpu_dec(bpf_raw_tp_nest_level);
1409                 return ERR_PTR(-EBUSY);
1410         }
1411
1412         return &tp_regs->regs[nest_level - 1];
1413 }
1414
1415 static void put_bpf_raw_tp_regs(void)
1416 {
1417         this_cpu_dec(bpf_raw_tp_nest_level);
1418 }
1419
1420 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args,
1421            struct bpf_map *, map, u64, flags, void *, data, u64, size)
1422 {
1423         struct pt_regs *regs = get_bpf_raw_tp_regs();
1424         int ret;
1425
1426         if (IS_ERR(regs))
1427                 return PTR_ERR(regs);
1428
1429         perf_fetch_caller_regs(regs);
1430         ret = ____bpf_perf_event_output(regs, map, flags, data, size);
1431
1432         put_bpf_raw_tp_regs();
1433         return ret;
1434 }
1435
1436 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = {
1437         .func           = bpf_perf_event_output_raw_tp,
1438         .gpl_only       = true,
1439         .ret_type       = RET_INTEGER,
1440         .arg1_type      = ARG_PTR_TO_CTX,
1441         .arg2_type      = ARG_CONST_MAP_PTR,
1442         .arg3_type      = ARG_ANYTHING,
1443         .arg4_type      = ARG_PTR_TO_MEM,
1444         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
1445 };
1446
1447 extern const struct bpf_func_proto bpf_skb_output_proto;
1448 extern const struct bpf_func_proto bpf_xdp_output_proto;
1449
1450 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args,
1451            struct bpf_map *, map, u64, flags)
1452 {
1453         struct pt_regs *regs = get_bpf_raw_tp_regs();
1454         int ret;
1455
1456         if (IS_ERR(regs))
1457                 return PTR_ERR(regs);
1458
1459         perf_fetch_caller_regs(regs);
1460         /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */
1461         ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map,
1462                               flags, 0, 0);
1463         put_bpf_raw_tp_regs();
1464         return ret;
1465 }
1466
1467 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = {
1468         .func           = bpf_get_stackid_raw_tp,
1469         .gpl_only       = true,
1470         .ret_type       = RET_INTEGER,
1471         .arg1_type      = ARG_PTR_TO_CTX,
1472         .arg2_type      = ARG_CONST_MAP_PTR,
1473         .arg3_type      = ARG_ANYTHING,
1474 };
1475
1476 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args,
1477            void *, buf, u32, size, u64, flags)
1478 {
1479         struct pt_regs *regs = get_bpf_raw_tp_regs();
1480         int ret;
1481
1482         if (IS_ERR(regs))
1483                 return PTR_ERR(regs);
1484
1485         perf_fetch_caller_regs(regs);
1486         ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf,
1487                             (unsigned long) size, flags, 0);
1488         put_bpf_raw_tp_regs();
1489         return ret;
1490 }
1491
1492 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = {
1493         .func           = bpf_get_stack_raw_tp,
1494         .gpl_only       = true,
1495         .ret_type       = RET_INTEGER,
1496         .arg1_type      = ARG_PTR_TO_CTX,
1497         .arg2_type      = ARG_PTR_TO_MEM,
1498         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
1499         .arg4_type      = ARG_ANYTHING,
1500 };
1501
1502 static const struct bpf_func_proto *
1503 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1504 {
1505         switch (func_id) {
1506         case BPF_FUNC_perf_event_output:
1507                 return &bpf_perf_event_output_proto_raw_tp;
1508         case BPF_FUNC_get_stackid:
1509                 return &bpf_get_stackid_proto_raw_tp;
1510         case BPF_FUNC_get_stack:
1511                 return &bpf_get_stack_proto_raw_tp;
1512         default:
1513                 return bpf_tracing_func_proto(func_id, prog);
1514         }
1515 }
1516
1517 const struct bpf_func_proto *
1518 tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1519 {
1520         switch (func_id) {
1521 #ifdef CONFIG_NET
1522         case BPF_FUNC_skb_output:
1523                 return &bpf_skb_output_proto;
1524         case BPF_FUNC_xdp_output:
1525                 return &bpf_xdp_output_proto;
1526         case BPF_FUNC_skc_to_tcp6_sock:
1527                 return &bpf_skc_to_tcp6_sock_proto;
1528         case BPF_FUNC_skc_to_tcp_sock:
1529                 return &bpf_skc_to_tcp_sock_proto;
1530         case BPF_FUNC_skc_to_tcp_timewait_sock:
1531                 return &bpf_skc_to_tcp_timewait_sock_proto;
1532         case BPF_FUNC_skc_to_tcp_request_sock:
1533                 return &bpf_skc_to_tcp_request_sock_proto;
1534         case BPF_FUNC_skc_to_udp6_sock:
1535                 return &bpf_skc_to_udp6_sock_proto;
1536 #endif
1537         case BPF_FUNC_seq_printf:
1538                 return prog->expected_attach_type == BPF_TRACE_ITER ?
1539                        &bpf_seq_printf_proto :
1540                        NULL;
1541         case BPF_FUNC_seq_write:
1542                 return prog->expected_attach_type == BPF_TRACE_ITER ?
1543                        &bpf_seq_write_proto :
1544                        NULL;
1545         default:
1546                 return raw_tp_prog_func_proto(func_id, prog);
1547         }
1548 }
1549
1550 static bool raw_tp_prog_is_valid_access(int off, int size,
1551                                         enum bpf_access_type type,
1552                                         const struct bpf_prog *prog,
1553                                         struct bpf_insn_access_aux *info)
1554 {
1555         if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
1556                 return false;
1557         if (type != BPF_READ)
1558                 return false;
1559         if (off % size != 0)
1560                 return false;
1561         return true;
1562 }
1563
1564 static bool tracing_prog_is_valid_access(int off, int size,
1565                                          enum bpf_access_type type,
1566                                          const struct bpf_prog *prog,
1567                                          struct bpf_insn_access_aux *info)
1568 {
1569         if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
1570                 return false;
1571         if (type != BPF_READ)
1572                 return false;
1573         if (off % size != 0)
1574                 return false;
1575         return btf_ctx_access(off, size, type, prog, info);
1576 }
1577
1578 int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog,
1579                                      const union bpf_attr *kattr,
1580                                      union bpf_attr __user *uattr)
1581 {
1582         return -ENOTSUPP;
1583 }
1584
1585 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
1586         .get_func_proto  = raw_tp_prog_func_proto,
1587         .is_valid_access = raw_tp_prog_is_valid_access,
1588 };
1589
1590 const struct bpf_prog_ops raw_tracepoint_prog_ops = {
1591 };
1592
1593 const struct bpf_verifier_ops tracing_verifier_ops = {
1594         .get_func_proto  = tracing_prog_func_proto,
1595         .is_valid_access = tracing_prog_is_valid_access,
1596 };
1597
1598 const struct bpf_prog_ops tracing_prog_ops = {
1599         .test_run = bpf_prog_test_run_tracing,
1600 };
1601
1602 static bool raw_tp_writable_prog_is_valid_access(int off, int size,
1603                                                  enum bpf_access_type type,
1604                                                  const struct bpf_prog *prog,
1605                                                  struct bpf_insn_access_aux *info)
1606 {
1607         if (off == 0) {
1608                 if (size != sizeof(u64) || type != BPF_READ)
1609                         return false;
1610                 info->reg_type = PTR_TO_TP_BUFFER;
1611         }
1612         return raw_tp_prog_is_valid_access(off, size, type, prog, info);
1613 }
1614
1615 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = {
1616         .get_func_proto  = raw_tp_prog_func_proto,
1617         .is_valid_access = raw_tp_writable_prog_is_valid_access,
1618 };
1619
1620 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = {
1621 };
1622
1623 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
1624                                     const struct bpf_prog *prog,
1625                                     struct bpf_insn_access_aux *info)
1626 {
1627         const int size_u64 = sizeof(u64);
1628
1629         if (off < 0 || off >= sizeof(struct bpf_perf_event_data))
1630                 return false;
1631         if (type != BPF_READ)
1632                 return false;
1633         if (off % size != 0) {
1634                 if (sizeof(unsigned long) != 4)
1635                         return false;
1636                 if (size != 8)
1637                         return false;
1638                 if (off % size != 4)
1639                         return false;
1640         }
1641
1642         switch (off) {
1643         case bpf_ctx_range(struct bpf_perf_event_data, sample_period):
1644                 bpf_ctx_record_field_size(info, size_u64);
1645                 if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
1646                         return false;
1647                 break;
1648         case bpf_ctx_range(struct bpf_perf_event_data, addr):
1649                 bpf_ctx_record_field_size(info, size_u64);
1650                 if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
1651                         return false;
1652                 break;
1653         default:
1654                 if (size != sizeof(long))
1655                         return false;
1656         }
1657
1658         return true;
1659 }
1660
1661 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
1662                                       const struct bpf_insn *si,
1663                                       struct bpf_insn *insn_buf,
1664                                       struct bpf_prog *prog, u32 *target_size)
1665 {
1666         struct bpf_insn *insn = insn_buf;
1667
1668         switch (si->off) {
1669         case offsetof(struct bpf_perf_event_data, sample_period):
1670                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
1671                                                        data), si->dst_reg, si->src_reg,
1672                                       offsetof(struct bpf_perf_event_data_kern, data));
1673                 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
1674                                       bpf_target_off(struct perf_sample_data, period, 8,
1675                                                      target_size));
1676                 break;
1677         case offsetof(struct bpf_perf_event_data, addr):
1678                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
1679                                                        data), si->dst_reg, si->src_reg,
1680                                       offsetof(struct bpf_perf_event_data_kern, data));
1681                 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
1682                                       bpf_target_off(struct perf_sample_data, addr, 8,
1683                                                      target_size));
1684                 break;
1685         default:
1686                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
1687                                                        regs), si->dst_reg, si->src_reg,
1688                                       offsetof(struct bpf_perf_event_data_kern, regs));
1689                 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg,
1690                                       si->off);
1691                 break;
1692         }
1693
1694         return insn - insn_buf;
1695 }
1696
1697 const struct bpf_verifier_ops perf_event_verifier_ops = {
1698         .get_func_proto         = pe_prog_func_proto,
1699         .is_valid_access        = pe_prog_is_valid_access,
1700         .convert_ctx_access     = pe_prog_convert_ctx_access,
1701 };
1702
1703 const struct bpf_prog_ops perf_event_prog_ops = {
1704 };
1705
1706 static DEFINE_MUTEX(bpf_event_mutex);
1707
1708 #define BPF_TRACE_MAX_PROGS 64
1709
1710 int perf_event_attach_bpf_prog(struct perf_event *event,
1711                                struct bpf_prog *prog)
1712 {
1713         struct bpf_prog_array *old_array;
1714         struct bpf_prog_array *new_array;
1715         int ret = -EEXIST;
1716
1717         /*
1718          * Kprobe override only works if they are on the function entry,
1719          * and only if they are on the opt-in list.
1720          */
1721         if (prog->kprobe_override &&
1722             (!trace_kprobe_on_func_entry(event->tp_event) ||
1723              !trace_kprobe_error_injectable(event->tp_event)))
1724                 return -EINVAL;
1725
1726         mutex_lock(&bpf_event_mutex);
1727
1728         if (event->prog)
1729                 goto unlock;
1730
1731         old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);
1732         if (old_array &&
1733             bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) {
1734                 ret = -E2BIG;
1735                 goto unlock;
1736         }
1737
1738         ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array);
1739         if (ret < 0)
1740                 goto unlock;
1741
1742         /* set the new array to event->tp_event and set event->prog */
1743         event->prog = prog;
1744         rcu_assign_pointer(event->tp_event->prog_array, new_array);
1745         bpf_prog_array_free(old_array);
1746
1747 unlock:
1748         mutex_unlock(&bpf_event_mutex);
1749         return ret;
1750 }
1751
1752 void perf_event_detach_bpf_prog(struct perf_event *event)
1753 {
1754         struct bpf_prog_array *old_array;
1755         struct bpf_prog_array *new_array;
1756         int ret;
1757
1758         mutex_lock(&bpf_event_mutex);
1759
1760         if (!event->prog)
1761                 goto unlock;
1762
1763         old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);
1764         ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array);
1765         if (ret == -ENOENT)
1766                 goto unlock;
1767         if (ret < 0) {
1768                 bpf_prog_array_delete_safe(old_array, event->prog);
1769         } else {
1770                 rcu_assign_pointer(event->tp_event->prog_array, new_array);
1771                 bpf_prog_array_free(old_array);
1772         }
1773
1774         bpf_prog_put(event->prog);
1775         event->prog = NULL;
1776
1777 unlock:
1778         mutex_unlock(&bpf_event_mutex);
1779 }
1780
1781 int perf_event_query_prog_array(struct perf_event *event, void __user *info)
1782 {
1783         struct perf_event_query_bpf __user *uquery = info;
1784         struct perf_event_query_bpf query = {};
1785         struct bpf_prog_array *progs;
1786         u32 *ids, prog_cnt, ids_len;
1787         int ret;
1788
1789         if (!perfmon_capable())
1790                 return -EPERM;
1791         if (event->attr.type != PERF_TYPE_TRACEPOINT)
1792                 return -EINVAL;
1793         if (copy_from_user(&query, uquery, sizeof(query)))
1794                 return -EFAULT;
1795
1796         ids_len = query.ids_len;
1797         if (ids_len > BPF_TRACE_MAX_PROGS)
1798                 return -E2BIG;
1799         ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN);
1800         if (!ids)
1801                 return -ENOMEM;
1802         /*
1803          * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which
1804          * is required when user only wants to check for uquery->prog_cnt.
1805          * There is no need to check for it since the case is handled
1806          * gracefully in bpf_prog_array_copy_info.
1807          */
1808
1809         mutex_lock(&bpf_event_mutex);
1810         progs = bpf_event_rcu_dereference(event->tp_event->prog_array);
1811         ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt);
1812         mutex_unlock(&bpf_event_mutex);
1813
1814         if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) ||
1815             copy_to_user(uquery->ids, ids, ids_len * sizeof(u32)))
1816                 ret = -EFAULT;
1817
1818         kfree(ids);
1819         return ret;
1820 }
1821
1822 extern struct bpf_raw_event_map __start__bpf_raw_tp[];
1823 extern struct bpf_raw_event_map __stop__bpf_raw_tp[];
1824
1825 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name)
1826 {
1827         struct bpf_raw_event_map *btp = __start__bpf_raw_tp;
1828
1829         for (; btp < __stop__bpf_raw_tp; btp++) {
1830                 if (!strcmp(btp->tp->name, name))
1831                         return btp;
1832         }
1833
1834         return bpf_get_raw_tracepoint_module(name);
1835 }
1836
1837 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
1838 {
1839         struct module *mod = __module_address((unsigned long)btp);
1840
1841         if (mod)
1842                 module_put(mod);
1843 }
1844
1845 static __always_inline
1846 void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
1847 {
1848         cant_sleep();
1849         rcu_read_lock();
1850         (void) BPF_PROG_RUN(prog, args);
1851         rcu_read_unlock();
1852 }
1853
1854 #define UNPACK(...)                     __VA_ARGS__
1855 #define REPEAT_1(FN, DL, X, ...)        FN(X)
1856 #define REPEAT_2(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__)
1857 #define REPEAT_3(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__)
1858 #define REPEAT_4(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__)
1859 #define REPEAT_5(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__)
1860 #define REPEAT_6(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__)
1861 #define REPEAT_7(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__)
1862 #define REPEAT_8(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__)
1863 #define REPEAT_9(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__)
1864 #define REPEAT_10(FN, DL, X, ...)       FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__)
1865 #define REPEAT_11(FN, DL, X, ...)       FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__)
1866 #define REPEAT_12(FN, DL, X, ...)       FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__)
1867 #define REPEAT(X, FN, DL, ...)          REPEAT_##X(FN, DL, __VA_ARGS__)
1868
1869 #define SARG(X)         u64 arg##X
1870 #define COPY(X)         args[X] = arg##X
1871
1872 #define __DL_COM        (,)
1873 #define __DL_SEM        (;)
1874
1875 #define __SEQ_0_11      0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
1876
1877 #define BPF_TRACE_DEFN_x(x)                                             \
1878         void bpf_trace_run##x(struct bpf_prog *prog,                    \
1879                               REPEAT(x, SARG, __DL_COM, __SEQ_0_11))    \
1880         {                                                               \
1881                 u64 args[x];                                            \
1882                 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11);                  \
1883                 __bpf_trace_run(prog, args);                            \
1884         }                                                               \
1885         EXPORT_SYMBOL_GPL(bpf_trace_run##x)
1886 BPF_TRACE_DEFN_x(1);
1887 BPF_TRACE_DEFN_x(2);
1888 BPF_TRACE_DEFN_x(3);
1889 BPF_TRACE_DEFN_x(4);
1890 BPF_TRACE_DEFN_x(5);
1891 BPF_TRACE_DEFN_x(6);
1892 BPF_TRACE_DEFN_x(7);
1893 BPF_TRACE_DEFN_x(8);
1894 BPF_TRACE_DEFN_x(9);
1895 BPF_TRACE_DEFN_x(10);
1896 BPF_TRACE_DEFN_x(11);
1897 BPF_TRACE_DEFN_x(12);
1898
1899 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
1900 {
1901         struct tracepoint *tp = btp->tp;
1902
1903         /*
1904          * check that program doesn't access arguments beyond what's
1905          * available in this tracepoint
1906          */
1907         if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64))
1908                 return -EINVAL;
1909
1910         if (prog->aux->max_tp_access > btp->writable_size)
1911                 return -EINVAL;
1912
1913         return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog);
1914 }
1915
1916 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
1917 {
1918         return __bpf_probe_register(btp, prog);
1919 }
1920
1921 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
1922 {
1923         return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog);
1924 }
1925
1926 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
1927                             u32 *fd_type, const char **buf,
1928                             u64 *probe_offset, u64 *probe_addr)
1929 {
1930         bool is_tracepoint, is_syscall_tp;
1931         struct bpf_prog *prog;
1932         int flags, err = 0;
1933
1934         prog = event->prog;
1935         if (!prog)
1936                 return -ENOENT;
1937
1938         /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */
1939         if (prog->type == BPF_PROG_TYPE_PERF_EVENT)
1940                 return -EOPNOTSUPP;
1941
1942         *prog_id = prog->aux->id;
1943         flags = event->tp_event->flags;
1944         is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT;
1945         is_syscall_tp = is_syscall_trace_event(event->tp_event);
1946
1947         if (is_tracepoint || is_syscall_tp) {
1948                 *buf = is_tracepoint ? event->tp_event->tp->name
1949                                      : event->tp_event->name;
1950                 *fd_type = BPF_FD_TYPE_TRACEPOINT;
1951                 *probe_offset = 0x0;
1952                 *probe_addr = 0x0;
1953         } else {
1954                 /* kprobe/uprobe */
1955                 err = -EOPNOTSUPP;
1956 #ifdef CONFIG_KPROBE_EVENTS
1957                 if (flags & TRACE_EVENT_FL_KPROBE)
1958                         err = bpf_get_kprobe_info(event, fd_type, buf,
1959                                                   probe_offset, probe_addr,
1960                                                   event->attr.type == PERF_TYPE_TRACEPOINT);
1961 #endif
1962 #ifdef CONFIG_UPROBE_EVENTS
1963                 if (flags & TRACE_EVENT_FL_UPROBE)
1964                         err = bpf_get_uprobe_info(event, fd_type, buf,
1965                                                   probe_offset,
1966                                                   event->attr.type == PERF_TYPE_TRACEPOINT);
1967 #endif
1968         }
1969
1970         return err;
1971 }
1972
1973 static int __init send_signal_irq_work_init(void)
1974 {
1975         int cpu;
1976         struct send_signal_irq_work *work;
1977
1978         for_each_possible_cpu(cpu) {
1979                 work = per_cpu_ptr(&send_signal_work, cpu);
1980                 init_irq_work(&work->irq_work, do_bpf_send_signal);
1981         }
1982         return 0;
1983 }
1984
1985 subsys_initcall(send_signal_irq_work_init);
1986
1987 #ifdef CONFIG_MODULES
1988 static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
1989                             void *module)
1990 {
1991         struct bpf_trace_module *btm, *tmp;
1992         struct module *mod = module;
1993
1994         if (mod->num_bpf_raw_events == 0 ||
1995             (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
1996                 return 0;
1997
1998         mutex_lock(&bpf_module_mutex);
1999
2000         switch (op) {
2001         case MODULE_STATE_COMING:
2002                 btm = kzalloc(sizeof(*btm), GFP_KERNEL);
2003                 if (btm) {
2004                         btm->module = module;
2005                         list_add(&btm->list, &bpf_trace_modules);
2006                 }
2007                 break;
2008         case MODULE_STATE_GOING:
2009                 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) {
2010                         if (btm->module == module) {
2011                                 list_del(&btm->list);
2012                                 kfree(btm);
2013                                 break;
2014                         }
2015                 }
2016                 break;
2017         }
2018
2019         mutex_unlock(&bpf_module_mutex);
2020
2021         return 0;
2022 }
2023
2024 static struct notifier_block bpf_module_nb = {
2025         .notifier_call = bpf_event_notify,
2026 };
2027
2028 static int __init bpf_event_init(void)
2029 {
2030         register_module_notifier(&bpf_module_nb);
2031         return 0;
2032 }
2033
2034 fs_initcall(bpf_event_init);
2035 #endif /* CONFIG_MODULES */