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/spinlock.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/error-injection.h>
  17 #include <linux/btf_ids.h>
  18
  19 #include <asm/tlb.h>
  20
  21 #include "trace_probe.h"
  22 #include "trace.h"
  23
  24 #define CREATE_TRACE_POINTS
  25 #include "bpf_trace.h"
  26
  27 #define bpf_event_rcu_dereference(p)                                    \
  28         rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex))
  29
  30 #ifdef CONFIG_MODULES
  31 struct bpf_trace_module {
  32         struct module *module;
  33         struct list_head list;
  34 };
  35
  36 static LIST_HEAD(bpf_trace_modules);
  37 static DEFINE_MUTEX(bpf_module_mutex);
  38
  39 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name)
  40 {
  41         struct bpf_raw_event_map *btp, *ret = NULL;
  42         struct bpf_trace_module *btm;
  43         unsigned int i;
  44
  45         mutex_lock(&bpf_module_mutex);
  46         list_for_each_entry(btm, &bpf_trace_modules, list) {
  47                 for (i = 0; i < btm->module->num_bpf_raw_events; ++i) {
  48                         btp = &btm->module->bpf_raw_events[i];
  49                         if (!strcmp(btp->tp->name, name)) {
  50                                 if (try_module_get(btm->module))
  51                                         ret = btp;
  52                                 goto out;
  53                         }
  54                 }
  55         }
  56 out:
  57         mutex_unlock(&bpf_module_mutex);
  58         return ret;
  59 }
  60 #else
  61 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name)
  62 {
  63         return NULL;
  64 }
  65 #endif /* CONFIG_MODULES */
  66
  67 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  68 u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  69
  70 /**
  71  * trace_call_bpf - invoke BPF program
  72  * @call: tracepoint event
  73  * @ctx: opaque context pointer
  74  *
  75  * kprobe handlers execute BPF programs via this helper.
  76  * Can be used from static tracepoints in the future.
  77  *
  78  * Return: BPF programs always return an integer which is interpreted by
  79  * kprobe handler as:
  80  * 0 - return from kprobe (event is filtered out)
  81  * 1 - store kprobe event into ring buffer
  82  * Other values are reserved and currently alias to 1
  83  */
  84 unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
  85 {
  86         unsigned int ret;
  87
  88         if (in_nmi()) /* not supported yet */
  89                 return 1;
  90
  91         cant_sleep();
  92
  93         if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
  94                 /*
  95                  * since some bpf program is already running on this cpu,
  96                  * don't call into another bpf program (same or different)
  97                  * and don't send kprobe event into ring-buffer,
  98                  * so return zero here
  99                  */
 100                 ret = 0;
 101                 goto out;
 102         }
 103
 104         /*
 105          * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock
 106          * to all call sites, we did a bpf_prog_array_valid() there to check
 107          * whether call->prog_array is empty or not, which is
 108          * a heurisitc to speed up execution.
 109          *
 110          * If bpf_prog_array_valid() fetched prog_array was
 111          * non-NULL, we go into trace_call_bpf() and do the actual
 112          * proper rcu_dereference() under RCU lock.
 113          * If it turns out that prog_array is NULL then, we bail out.
 114          * For the opposite, if the bpf_prog_array_valid() fetched pointer
 115          * was NULL, you'll skip the prog_array with the risk of missing
 116          * out of events when it was updated in between this and the
 117          * rcu_dereference() which is accepted risk.
 118          */
 119         ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN);
 120
 121  out:
 122         __this_cpu_dec(bpf_prog_active);
 123
 124         return ret;
 125 }
 126
 127 #ifdef CONFIG_BPF_KPROBE_OVERRIDE
 128 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc)
 129 {
 130         regs_set_return_value(regs, rc);
 131         override_function_with_return(regs);
 132         return 0;
 133 }
 134
 135 static const struct bpf_func_proto bpf_override_return_proto = {
 136         .func           = bpf_override_return,
 137         .gpl_only       = true,
 138         .ret_type       = RET_INTEGER,
 139         .arg1_type      = ARG_PTR_TO_CTX,
 140         .arg2_type      = ARG_ANYTHING,
 141 };
 142 #endif
 143
 144 static __always_inline int
 145 bpf_probe_read_user_common(void *dst, u32 size, const void __user *unsafe_ptr)
 146 {
 147         int ret;
 148
 149         ret = copy_from_user_nofault(dst, unsafe_ptr, size);
 150         if (unlikely(ret < 0))
 151                 memset(dst, 0, size);
 152         return ret;
 153 }
 154
 155 BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size,
 156            const void __user *, unsafe_ptr)
 157 {
 158         return bpf_probe_read_user_common(dst, size, unsafe_ptr);
 159 }
 160
 161 const struct bpf_func_proto bpf_probe_read_user_proto = {
 162         .func           = bpf_probe_read_user,
 163         .gpl_only       = true,
 164         .ret_type       = RET_INTEGER,
 165         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 166         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 167         .arg3_type      = ARG_ANYTHING,
 168 };
 169
 170 static __always_inline int
 171 bpf_probe_read_user_str_common(void *dst, u32 size,
 172                                const void __user *unsafe_ptr)
 173 {
 174         int ret;
 175
 176         ret = strncpy_from_user_nofault(dst, unsafe_ptr, size);
 177         if (unlikely(ret < 0))
 178                 memset(dst, 0, size);
 179         return ret;
 180 }
 181
 182 BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size,
 183            const void __user *, unsafe_ptr)
 184 {
 185         return bpf_probe_read_user_str_common(dst, size, unsafe_ptr);
 186 }
 187
 188 const struct bpf_func_proto bpf_probe_read_user_str_proto = {
 189         .func           = bpf_probe_read_user_str,
 190         .gpl_only       = true,
 191         .ret_type       = RET_INTEGER,
 192         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 193         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 194         .arg3_type      = ARG_ANYTHING,
 195 };
 196
 197 static __always_inline int
 198 bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr)
 199 {
 200         int ret = security_locked_down(LOCKDOWN_BPF_READ);
 201
 202         if (unlikely(ret < 0))
 203                 goto fail;
 204         ret = copy_from_kernel_nofault(dst, unsafe_ptr, size);
 205         if (unlikely(ret < 0))
 206                 goto fail;
 207         return ret;
 208 fail:
 209         memset(dst, 0, size);
 210         return ret;
 211 }
 212
 213 BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size,
 214            const void *, unsafe_ptr)
 215 {
 216         return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);
 217 }
 218
 219 const struct bpf_func_proto bpf_probe_read_kernel_proto = {
 220         .func           = bpf_probe_read_kernel,
 221         .gpl_only       = true,
 222         .ret_type       = RET_INTEGER,
 223         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 224         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 225         .arg3_type      = ARG_ANYTHING,
 226 };
 227
 228 static __always_inline int
 229 bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr)
 230 {
 231         int ret = security_locked_down(LOCKDOWN_BPF_READ);
 232
 233         if (unlikely(ret < 0))
 234                 goto fail;
 235
 236         /*
 237          * The strncpy_from_kernel_nofault() call will likely not fill the
 238          * entire buffer, but that's okay in this circumstance as we're probing
 239          * arbitrary memory anyway similar to bpf_probe_read_*() and might
 240          * as well probe the stack. Thus, memory is explicitly cleared
 241          * only in error case, so that improper users ignoring return
 242          * code altogether don't copy garbage; otherwise length of string
 243          * is returned that can be used for bpf_perf_event_output() et al.
 244          */
 245         ret = strncpy_from_kernel_nofault(dst, unsafe_ptr, size);
 246         if (unlikely(ret < 0))
 247                 goto fail;
 248
 249         return ret;
 250 fail:
 251         memset(dst, 0, size);
 252         return ret;
 253 }
 254
 255 BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size,
 256            const void *, unsafe_ptr)
 257 {
 258         return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);
 259 }
 260
 261 const struct bpf_func_proto bpf_probe_read_kernel_str_proto = {
 262         .func           = bpf_probe_read_kernel_str,
 263         .gpl_only       = true,
 264         .ret_type       = RET_INTEGER,
 265         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 266         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 267         .arg3_type      = ARG_ANYTHING,
 268 };
 269
 270 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 271 BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size,
 272            const void *, unsafe_ptr)
 273 {
 274         if ((unsigned long)unsafe_ptr < TASK_SIZE) {
 275                 return bpf_probe_read_user_common(dst, size,
 276                                 (__force void __user *)unsafe_ptr);
 277         }
 278         return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);
 279 }
 280
 281 static const struct bpf_func_proto bpf_probe_read_compat_proto = {
 282         .func           = bpf_probe_read_compat,
 283         .gpl_only       = true,
 284         .ret_type       = RET_INTEGER,
 285         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 286         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 287         .arg3_type      = ARG_ANYTHING,
 288 };
 289
 290 BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size,
 291            const void *, unsafe_ptr)
 292 {
 293         if ((unsigned long)unsafe_ptr < TASK_SIZE) {
 294                 return bpf_probe_read_user_str_common(dst, size,
 295                                 (__force void __user *)unsafe_ptr);
 296         }
 297         return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);
 298 }
 299
 300 static const struct bpf_func_proto bpf_probe_read_compat_str_proto = {
 301         .func           = bpf_probe_read_compat_str,
 302         .gpl_only       = true,
 303         .ret_type       = RET_INTEGER,
 304         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 305         .arg2_type      = ARG_CONST_SIZE_OR_ZERO,
 306         .arg3_type      = ARG_ANYTHING,
 307 };
 308 #endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
 309
 310 BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src,
 311            u32, size)
 312 {
 313         /*
 314          * Ensure we're in user context which is safe for the helper to
 315          * run. This helper has no business in a kthread.
 316          *
 317          * access_ok() should prevent writing to non-user memory, but in
 318          * some situations (nommu, temporary switch, etc) access_ok() does
 319          * not provide enough validation, hence the check on KERNEL_DS.
 320          *
 321          * nmi_uaccess_okay() ensures the probe is not run in an interim
 322          * state, when the task or mm are switched. This is specifically
 323          * required to prevent the use of temporary mm.
 324          */
 325
 326         if (unlikely(in_interrupt() ||
 327                      current->flags & (PF_KTHREAD | PF_EXITING)))
 328                 return -EPERM;
 329         if (unlikely(uaccess_kernel()))
 330                 return -EPERM;
 331         if (unlikely(!nmi_uaccess_okay()))
 332                 return -EPERM;
 333
 334         return copy_to_user_nofault(unsafe_ptr, src, size);
 335 }
 336
 337 static const struct bpf_func_proto bpf_probe_write_user_proto = {
 338         .func           = bpf_probe_write_user,
 339         .gpl_only       = true,
 340         .ret_type       = RET_INTEGER,
 341         .arg1_type      = ARG_ANYTHING,
 342         .arg2_type      = ARG_PTR_TO_MEM,
 343         .arg3_type      = ARG_CONST_SIZE,
 344 };
 345
 346 static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
 347 {
 348         if (!capable(CAP_SYS_ADMIN))
 349                 return NULL;
 350
 351         pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",
 352                             current->comm, task_pid_nr(current));
 353
 354         return &bpf_probe_write_user_proto;
 355 }
 356
 357 static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
 358                 size_t bufsz)
 359 {
 360         void __user *user_ptr = (__force void __user *)unsafe_ptr;
 361
 362         buf[0] = 0;
 363
 364         switch (fmt_ptype) {
 365         case 's':
 366 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 367                 if ((unsigned long)unsafe_ptr < TASK_SIZE) {
 368                         strncpy_from_user_nofault(buf, user_ptr, bufsz);
 369                         break;
 370                 }
 371                 fallthrough;
 372 #endif
 373         case 'k':
 374                 strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
 375                 break;
 376         case 'u':
 377                 strncpy_from_user_nofault(buf, user_ptr, bufsz);
 378                 break;
 379         }
 380 }
 381
 382 static DEFINE_RAW_SPINLOCK(trace_printk_lock);
 383
 384 #define BPF_TRACE_PRINTK_SIZE   1024
 385
 386 static __printf(1, 0) int bpf_do_trace_printk(const char *fmt, ...)
 387 {
 388         static char buf[BPF_TRACE_PRINTK_SIZE];
 389         unsigned long flags;
 390         va_list ap;
 391         int ret;
 392
 393         raw_spin_lock_irqsave(&trace_printk_lock, flags);
 394         va_start(ap, fmt);
 395         ret = vsnprintf(buf, sizeof(buf), fmt, ap);
 396         va_end(ap);
 397         /* vsnprintf() will not append null for zero-length strings */
 398         if (ret == 0)
 399                 buf[0] = '\0';
 400         trace_bpf_trace_printk(buf);
 401         raw_spin_unlock_irqrestore(&trace_printk_lock, flags);
 402
 403         return ret;
 404 }
 405
 406 /*
 407  * Only limited trace_printk() conversion specifiers allowed:
 408  * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s
 409  */
 410 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
 411            u64, arg2, u64, arg3)
 412 {
 413         int i, mod[3] = {}, fmt_cnt = 0;
 414         char buf[64], fmt_ptype;
 415         void *unsafe_ptr = NULL;
 416         bool str_seen = false;
 417
 418         /*
 419          * bpf_check()->check_func_arg()->check_stack_boundary()
 420          * guarantees that fmt points to bpf program stack,
 421          * fmt_size bytes of it were initialized and fmt_size > 0
 422          */
 423         if (fmt[--fmt_size] != 0)
 424                 return -EINVAL;
 425
 426         /* check format string for allowed specifiers */
 427         for (i = 0; i < fmt_size; i++) {
 428                 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))
 429                         return -EINVAL;
 430
 431                 if (fmt[i] != '%')
 432                         continue;
 433
 434                 if (fmt_cnt >= 3)
 435                         return -EINVAL;
 436
 437                 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
 438                 i++;
 439                 if (fmt[i] == 'l') {
 440                         mod[fmt_cnt]++;
 441                         i++;
 442                 } else if (fmt[i] == 'p') {
 443                         mod[fmt_cnt]++;
 444                         if ((fmt[i + 1] == 'k' ||
 445                              fmt[i + 1] == 'u') &&
 446                             fmt[i + 2] == 's') {
 447                                 fmt_ptype = fmt[i + 1];
 448                                 i += 2;
 449                                 goto fmt_str;
 450                         }
 451
 452                         if (fmt[i + 1] == 'B') {
 453                                 i++;
 454                                 goto fmt_next;
 455                         }
 456
 457                         /* disallow any further format extensions */
 458                         if (fmt[i + 1] != 0 &&
 459                             !isspace(fmt[i + 1]) &&
 460                             !ispunct(fmt[i + 1]))
 461                                 return -EINVAL;
 462
 463                         goto fmt_next;
 464                 } else if (fmt[i] == 's') {
 465                         mod[fmt_cnt]++;
 466                         fmt_ptype = fmt[i];
 467 fmt_str:
 468                         if (str_seen)
 469                                 /* allow only one '%s' per fmt string */
 470                                 return -EINVAL;
 471                         str_seen = true;
 472
 473                         if (fmt[i + 1] != 0 &&
 474                             !isspace(fmt[i + 1]) &&
 475                             !ispunct(fmt[i + 1]))
 476                                 return -EINVAL;
 477
 478                         switch (fmt_cnt) {
 479                         case 0:
 480                                 unsafe_ptr = (void *)(long)arg1;
 481                                 arg1 = (long)buf;
 482                                 break;
 483                         case 1:
 484                                 unsafe_ptr = (void *)(long)arg2;
 485                                 arg2 = (long)buf;
 486                                 break;
 487                         case 2:
 488                                 unsafe_ptr = (void *)(long)arg3;
 489                                 arg3 = (long)buf;
 490                                 break;
 491                         }
 492
 493                         bpf_trace_copy_string(buf, unsafe_ptr, fmt_ptype,
 494                                         sizeof(buf));
 495                         goto fmt_next;
 496                 }
 497
 498                 if (fmt[i] == 'l') {
 499                         mod[fmt_cnt]++;
 500                         i++;
 501                 }
 502
 503                 if (fmt[i] != 'i' && fmt[i] != 'd' &&
 504                     fmt[i] != 'u' && fmt[i] != 'x')
 505                         return -EINVAL;
 506 fmt_next:
 507                 fmt_cnt++;
 508         }
 509
 510 /* Horrid workaround for getting va_list handling working with different
 511  * argument type combinations generically for 32 and 64 bit archs.
 512  */
 513 #define __BPF_TP_EMIT() __BPF_ARG3_TP()
 514 #define __BPF_TP(...)                                                   \
 515         bpf_do_trace_printk(fmt, ##__VA_ARGS__)
 516
 517 #define __BPF_ARG1_TP(...)                                              \
 518         ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64))        \
 519           ? __BPF_TP(arg1, ##__VA_ARGS__)                               \
 520           : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32))    \
 521               ? __BPF_TP((long)arg1, ##__VA_ARGS__)                     \
 522               : __BPF_TP((u32)arg1, ##__VA_ARGS__)))
 523
 524 #define __BPF_ARG2_TP(...)                                              \
 525         ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64))        \
 526           ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__)                          \
 527           : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32))    \
 528               ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__)                \
 529               : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__)))
 530
 531 #define __BPF_ARG3_TP(...)                                              \
 532         ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64))        \
 533           ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__)                          \
 534           : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32))    \
 535               ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__)                \
 536               : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__)))
 537
 538         return __BPF_TP_EMIT();
 539 }
 540
 541 static const struct bpf_func_proto bpf_trace_printk_proto = {
 542         .func           = bpf_trace_printk,
 543         .gpl_only       = true,
 544         .ret_type       = RET_INTEGER,
 545         .arg1_type      = ARG_PTR_TO_MEM,
 546         .arg2_type      = ARG_CONST_SIZE,
 547 };
 548
 549 const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
 550 {
 551         /*
 552          * This program might be calling bpf_trace_printk,
 553          * so enable the associated bpf_trace/bpf_trace_printk event.
 554          * Repeat this each time as it is possible a user has
 555          * disabled bpf_trace_printk events.  By loading a program
 556          * calling bpf_trace_printk() however the user has expressed
 557          * the intent to see such events.
 558          */
 559         if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1))
 560                 pr_warn_ratelimited("could not enable bpf_trace_printk events");
 561
 562         return &bpf_trace_printk_proto;
 563 }
 564
 565 #define MAX_SEQ_PRINTF_VARARGS          12
 566 #define MAX_SEQ_PRINTF_MAX_MEMCPY       6
 567 #define MAX_SEQ_PRINTF_STR_LEN          128
 568
 569 struct bpf_seq_printf_buf {
 570         char buf[MAX_SEQ_PRINTF_MAX_MEMCPY][MAX_SEQ_PRINTF_STR_LEN];
 571 };
 572 static DEFINE_PER_CPU(struct bpf_seq_printf_buf, bpf_seq_printf_buf);
 573 static DEFINE_PER_CPU(int, bpf_seq_printf_buf_used);
 574
 575 BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size,
 576            const void *, data, u32, data_len)
 577 {
 578         int err = -EINVAL, fmt_cnt = 0, memcpy_cnt = 0;
 579         int i, buf_used, copy_size, num_args;
 580         u64 params[MAX_SEQ_PRINTF_VARARGS];
 581         struct bpf_seq_printf_buf *bufs;
 582         const u64 *args = data;
 583
 584         buf_used = this_cpu_inc_return(bpf_seq_printf_buf_used);
 585         if (WARN_ON_ONCE(buf_used > 1)) {
 586                 err = -EBUSY;
 587                 goto out;
 588         }
 589
 590         bufs = this_cpu_ptr(&bpf_seq_printf_buf);
 591
 592         /*
 593          * bpf_check()->check_func_arg()->check_stack_boundary()
 594          * guarantees that fmt points to bpf program stack,
 595          * fmt_size bytes of it were initialized and fmt_size > 0
 596          */
 597         if (fmt[--fmt_size] != 0)
 598                 goto out;
 599
 600         if (data_len & 7)
 601                 goto out;
 602
 603         for (i = 0; i < fmt_size; i++) {
 604                 if (fmt[i] == '%') {
 605                         if (fmt[i + 1] == '%')
 606                                 i++;
 607                         else if (!data || !data_len)
 608                                 goto out;
 609                 }
 610         }
 611
 612         num_args = data_len / 8;
 613
 614         /* check format string for allowed specifiers */
 615         for (i = 0; i < fmt_size; i++) {
 616                 /* only printable ascii for now. */
 617                 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
 618                         err = -EINVAL;
 619                         goto out;
 620                 }
 621
 622                 if (fmt[i] != '%')
 623                         continue;
 624
 625                 if (fmt[i + 1] == '%') {
 626                         i++;
 627                         continue;
 628                 }
 629
 630                 if (fmt_cnt >= MAX_SEQ_PRINTF_VARARGS) {
 631                         err = -E2BIG;
 632                         goto out;
 633                 }
 634
 635                 if (fmt_cnt >= num_args) {
 636                         err = -EINVAL;
 637                         goto out;
 638                 }
 639
 640                 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
 641                 i++;
 642
 643                 /* skip optional "[0 +-][num]" width formating field */
 644                 while (fmt[i] == '0' || fmt[i] == '+'  || fmt[i] == '-' ||
 645                        fmt[i] == ' ')
 646                         i++;
 647                 if (fmt[i] >= '1' && fmt[i] <= '9') {
 648                         i++;
 649                         while (fmt[i] >= '0' && fmt[i] <= '9')
 650                                 i++;
 651                 }
 652
 653                 if (fmt[i] == 's') {
 654                         void *unsafe_ptr;
 655
 656                         /* try our best to copy */
 657                         if (memcpy_cnt >= MAX_SEQ_PRINTF_MAX_MEMCPY) {
 658                                 err = -E2BIG;
 659                                 goto out;
 660                         }
 661
 662                         unsafe_ptr = (void *)(long)args[fmt_cnt];
 663                         err = strncpy_from_kernel_nofault(bufs->buf[memcpy_cnt],
 664                                         unsafe_ptr, MAX_SEQ_PRINTF_STR_LEN);
 665                         if (err < 0)
 666                                 bufs->buf[memcpy_cnt][0] = '\0';
 667                         params[fmt_cnt] = (u64)(long)bufs->buf[memcpy_cnt];
 668
 669                         fmt_cnt++;
 670                         memcpy_cnt++;
 671                         continue;
 672                 }
 673
 674                 if (fmt[i] == 'p') {
 675                         if (fmt[i + 1] == 0 ||
 676                             fmt[i + 1] == 'K' ||
 677                             fmt[i + 1] == 'x' ||
 678                             fmt[i + 1] == 'B') {
 679                                 /* just kernel pointers */
 680                                 params[fmt_cnt] = args[fmt_cnt];
 681                                 fmt_cnt++;
 682                                 continue;
 683                         }
 684
 685                         /* only support "%pI4", "%pi4", "%pI6" and "%pi6". */
 686                         if (fmt[i + 1] != 'i' && fmt[i + 1] != 'I') {
 687                                 err = -EINVAL;
 688                                 goto out;
 689                         }
 690                         if (fmt[i + 2] != '4' && fmt[i + 2] != '6') {
 691                                 err = -EINVAL;
 692                                 goto out;
 693                         }
 694
 695                         if (memcpy_cnt >= MAX_SEQ_PRINTF_MAX_MEMCPY) {
 696                                 err = -E2BIG;
 697                                 goto out;
 698                         }
 699
 700
 701                         copy_size = (fmt[i + 2] == '4') ? 4 : 16;
 702
 703                         err = copy_from_kernel_nofault(bufs->buf[memcpy_cnt],
 704                                                 (void *) (long) args[fmt_cnt],
 705                                                 copy_size);
 706                         if (err < 0)
 707                                 memset(bufs->buf[memcpy_cnt], 0, copy_size);
 708                         params[fmt_cnt] = (u64)(long)bufs->buf[memcpy_cnt];
 709
 710                         i += 2;
 711                         fmt_cnt++;
 712                         memcpy_cnt++;
 713                         continue;
 714                 }
 715
 716                 if (fmt[i] == 'l') {
 717                         i++;
 718                         if (fmt[i] == 'l')
 719                                 i++;
 720                 }
 721
 722                 if (fmt[i] != 'i' && fmt[i] != 'd' &&
 723                     fmt[i] != 'u' && fmt[i] != 'x' &&
 724                     fmt[i] != 'X') {
 725                         err = -EINVAL;
 726                         goto out;
 727                 }
 728
 729                 params[fmt_cnt] = args[fmt_cnt];
 730                 fmt_cnt++;
 731         }
 732
 733         /* Maximumly we can have MAX_SEQ_PRINTF_VARARGS parameter, just give
 734          * all of them to seq_printf().
 735          */
 736         seq_printf(m, fmt, params[0], params[1], params[2], params[3],
 737                    params[4], params[5], params[6], params[7], params[8],
 738                    params[9], params[10], params[11]);
 739
 740         err = seq_has_overflowed(m) ? -EOVERFLOW : 0;
 741 out:
 742         this_cpu_dec(bpf_seq_printf_buf_used);
 743         return err;
 744 }
 745
 746 BTF_ID_LIST(bpf_seq_printf_btf_ids)
 747 BTF_ID(struct, seq_file)
 748
 749 static const struct bpf_func_proto bpf_seq_printf_proto = {
 750         .func           = bpf_seq_printf,
 751         .gpl_only       = true,
 752         .ret_type       = RET_INTEGER,
 753         .arg1_type      = ARG_PTR_TO_BTF_ID,
 754         .arg2_type      = ARG_PTR_TO_MEM,
 755         .arg3_type      = ARG_CONST_SIZE,
 756         .arg4_type      = ARG_PTR_TO_MEM_OR_NULL,
 757         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 758         .btf_id         = bpf_seq_printf_btf_ids,
 759 };
 760
 761 BPF_CALL_3(bpf_seq_write, struct seq_file *, m, const void *, data, u32, len)
 762 {
 763         return seq_write(m, data, len) ? -EOVERFLOW : 0;
 764 }
 765
 766 BTF_ID_LIST(bpf_seq_write_btf_ids)
 767 BTF_ID(struct, seq_file)
 768
 769 static const struct bpf_func_proto bpf_seq_write_proto = {
 770         .func           = bpf_seq_write,
 771         .gpl_only       = true,
 772         .ret_type       = RET_INTEGER,
 773         .arg1_type      = ARG_PTR_TO_BTF_ID,
 774         .arg2_type      = ARG_PTR_TO_MEM,
 775         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
 776         .btf_id         = bpf_seq_write_btf_ids,
 777 };
 778
 779 static __always_inline int
 780 get_map_perf_counter(struct bpf_map *map, u64 flags,
 781                      u64 *value, u64 *enabled, u64 *running)
 782 {
 783         struct bpf_array *array = container_of(map, struct bpf_array, map);
 784         unsigned int cpu = smp_processor_id();
 785         u64 index = flags & BPF_F_INDEX_MASK;
 786         struct bpf_event_entry *ee;
 787
 788         if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
 789                 return -EINVAL;
 790         if (index == BPF_F_CURRENT_CPU)
 791                 index = cpu;
 792         if (unlikely(index >= array->map.max_entries))
 793                 return -E2BIG;
 794
 795         ee = READ_ONCE(array->ptrs[index]);
 796         if (!ee)
 797                 return -ENOENT;
 798
 799         return perf_event_read_local(ee->event, value, enabled, running);
 800 }
 801
 802 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
 803 {
 804         u64 value = 0;
 805         int err;
 806
 807         err = get_map_perf_counter(map, flags, &value, NULL, NULL);
 808         /*
 809          * this api is ugly since we miss [-22..-2] range of valid
 810          * counter values, but that's uapi
 811          */
 812         if (err)
 813                 return err;
 814         return value;
 815 }
 816
 817 static const struct bpf_func_proto bpf_perf_event_read_proto = {
 818         .func           = bpf_perf_event_read,
 819         .gpl_only       = true,
 820         .ret_type       = RET_INTEGER,
 821         .arg1_type      = ARG_CONST_MAP_PTR,
 822         .arg2_type      = ARG_ANYTHING,
 823 };
 824
 825 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags,
 826            struct bpf_perf_event_value *, buf, u32, size)
 827 {
 828         int err = -EINVAL;
 829
 830         if (unlikely(size != sizeof(struct bpf_perf_event_value)))
 831                 goto clear;
 832         err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled,
 833                                    &buf->running);
 834         if (unlikely(err))
 835                 goto clear;
 836         return 0;
 837 clear:
 838         memset(buf, 0, size);
 839         return err;
 840 }
 841
 842 static const struct bpf_func_proto bpf_perf_event_read_value_proto = {
 843         .func           = bpf_perf_event_read_value,
 844         .gpl_only       = true,
 845         .ret_type       = RET_INTEGER,
 846         .arg1_type      = ARG_CONST_MAP_PTR,
 847         .arg2_type      = ARG_ANYTHING,
 848         .arg3_type      = ARG_PTR_TO_UNINIT_MEM,
 849         .arg4_type      = ARG_CONST_SIZE,
 850 };
 851
 852 static __always_inline u64
 853 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
 854                         u64 flags, struct perf_sample_data *sd)
 855 {
 856         struct bpf_array *array = container_of(map, struct bpf_array, map);
 857         unsigned int cpu = smp_processor_id();
 858         u64 index = flags & BPF_F_INDEX_MASK;
 859         struct bpf_event_entry *ee;
 860         struct perf_event *event;
 861
 862         if (index == BPF_F_CURRENT_CPU)
 863                 index = cpu;
 864         if (unlikely(index >= array->map.max_entries))
 865                 return -E2BIG;
 866
 867         ee = READ_ONCE(array->ptrs[index]);
 868         if (!ee)
 869                 return -ENOENT;
 870
 871         event = ee->event;
 872         if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
 873                      event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
 874                 return -EINVAL;
 875
 876         if (unlikely(event->oncpu != cpu))
 877                 return -EOPNOTSUPP;
 878
 879         return perf_event_output(event, sd, regs);
 880 }
 881
 882 /*
 883  * Support executing tracepoints in normal, irq, and nmi context that each call
 884  * bpf_perf_event_output
 885  */
 886 struct bpf_trace_sample_data {
 887         struct perf_sample_data sds[3];
 888 };
 889
 890 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds);
 891 static DEFINE_PER_CPU(int, bpf_trace_nest_level);
 892 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
 893            u64, flags, void *, data, u64, size)
 894 {
 895         struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds);
 896         int nest_level = this_cpu_inc_return(bpf_trace_nest_level);
 897         struct perf_raw_record raw = {
 898                 .frag = {
 899                         .size = size,
 900                         .data = data,
 901                 },
 902         };
 903         struct perf_sample_data *sd;
 904         int err;
 905
 906         if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) {
 907                 err = -EBUSY;
 908                 goto out;
 909         }
 910
 911         sd = &sds->sds[nest_level - 1];
 912
 913         if (unlikely(flags & ~(BPF_F_INDEX_MASK))) {
 914                 err = -EINVAL;
 915                 goto out;
 916         }
 917
 918         perf_sample_data_init(sd, 0, 0);
 919         sd->raw = &raw;
 920
 921         err = __bpf_perf_event_output(regs, map, flags, sd);
 922
 923 out:
 924         this_cpu_dec(bpf_trace_nest_level);
 925         return err;
 926 }
 927
 928 static const struct bpf_func_proto bpf_perf_event_output_proto = {
 929         .func           = bpf_perf_event_output,
 930         .gpl_only       = true,
 931         .ret_type       = RET_INTEGER,
 932         .arg1_type      = ARG_PTR_TO_CTX,
 933         .arg2_type      = ARG_CONST_MAP_PTR,
 934         .arg3_type      = ARG_ANYTHING,
 935         .arg4_type      = ARG_PTR_TO_MEM,
 936         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 937 };
 938
 939 static DEFINE_PER_CPU(int, bpf_event_output_nest_level);
 940 struct bpf_nested_pt_regs {
 941         struct pt_regs regs[3];
 942 };
 943 static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs);
 944 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds);
 945
 946 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
 947                      void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
 948 {
 949         int nest_level = this_cpu_inc_return(bpf_event_output_nest_level);
 950         struct perf_raw_frag frag = {
 951                 .copy           = ctx_copy,
 952                 .size           = ctx_size,
 953                 .data           = ctx,
 954         };
 955         struct perf_raw_record raw = {
 956                 .frag = {
 957                         {
 958                                 .next   = ctx_size ? &frag : NULL,
 959                         },
 960                         .size   = meta_size,
 961                         .data   = meta,
 962                 },
 963         };
 964         struct perf_sample_data *sd;
 965         struct pt_regs *regs;
 966         u64 ret;
 967
 968         if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) {
 969                 ret = -EBUSY;
 970                 goto out;
 971         }
 972         sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]);
 973         regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]);
 974
 975         perf_fetch_caller_regs(regs);
 976         perf_sample_data_init(sd, 0, 0);
 977         sd->raw = &raw;
 978
 979         ret = __bpf_perf_event_output(regs, map, flags, sd);
 980 out:
 981         this_cpu_dec(bpf_event_output_nest_level);
 982         return ret;
 983 }
 984
 985 BPF_CALL_0(bpf_get_current_task)
 986 {
 987         return (long) current;
 988 }
 989
 990 const struct bpf_func_proto bpf_get_current_task_proto = {
 991         .func           = bpf_get_current_task,
 992         .gpl_only       = true,
 993         .ret_type       = RET_INTEGER,
 994 };
 995
 996 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx)
 997 {
 998         struct bpf_array *array = container_of(map, struct bpf_array, map);
 999         struct cgroup *cgrp;
1000
1001         if (unlikely(idx >= array->map.max_entries))
1002                 return -E2BIG;
1003
1004         cgrp = READ_ONCE(array->ptrs[idx]);
1005         if (unlikely(!cgrp))
1006                 return -EAGAIN;
1007
1008         return task_under_cgroup_hierarchy(current, cgrp);
1009 }
1010
1011 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = {
1012         .func           = bpf_current_task_under_cgroup,
1013         .gpl_only       = false,
1014         .ret_type       = RET_INTEGER,
1015         .arg1_type      = ARG_CONST_MAP_PTR,
1016         .arg2_type      = ARG_ANYTHING,
1017 };
1018
1019 struct send_signal_irq_work {
1020         struct irq_work irq_work;
1021         struct task_struct *task;
1022         u32 sig;
1023         enum pid_type type;
1024 };
1025
1026 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work);
1027
1028 static void do_bpf_send_signal(struct irq_work *entry)
1029 {
1030         struct send_signal_irq_work *work;
1031
1032         work = container_of(entry, struct send_signal_irq_work, irq_work);
1033         group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type);
1034 }
1035
1036 static int bpf_send_signal_common(u32 sig, enum pid_type type)
1037 {
1038         struct send_signal_irq_work *work = NULL;
1039
1040         /* Similar to bpf_probe_write_user, task needs to be
1041          * in a sound condition and kernel memory access be
1042          * permitted in order to send signal to the current
1043          * task.
1044          */
1045         if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING)))
1046                 return -EPERM;
1047         if (unlikely(uaccess_kernel()))
1048                 return -EPERM;
1049         if (unlikely(!nmi_uaccess_okay()))
1050                 return -EPERM;
1051
1052         if (irqs_disabled()) {
1053                 /* Do an early check on signal validity. Otherwise,
1054                  * the error is lost in deferred irq_work.
1055                  */
1056                 if (unlikely(!valid_signal(sig)))
1057                         return -EINVAL;
1058
1059                 work = this_cpu_ptr(&send_signal_work);
1060                 if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY)
1061                         return -EBUSY;
1062
1063                 /* Add the current task, which is the target of sending signal,
1064                  * to the irq_work. The current task may change when queued
1065                  * irq works get executed.
1066                  */
1067                 work->task = current;
1068                 work->sig = sig;
1069                 work->type = type;
1070                 irq_work_queue(&work->irq_work);
1071                 return 0;
1072         }
1073
1074         return group_send_sig_info(sig, SEND_SIG_PRIV, current, type);
1075 }
1076
1077 BPF_CALL_1(bpf_send_signal, u32, sig)
1078 {
1079         return bpf_send_signal_common(sig, PIDTYPE_TGID);
1080 }
1081
1082 static const struct bpf_func_proto bpf_send_signal_proto = {
1083         .func           = bpf_send_signal,
1084         .gpl_only       = false,
1085         .ret_type       = RET_INTEGER,
1086         .arg1_type      = ARG_ANYTHING,
1087 };
1088
1089 BPF_CALL_1(bpf_send_signal_thread, u32, sig)
1090 {
1091         return bpf_send_signal_common(sig, PIDTYPE_PID);
1092 }
1093
1094 static const struct bpf_func_proto bpf_send_signal_thread_proto = {
1095         .func           = bpf_send_signal_thread,
1096         .gpl_only       = false,
1097         .ret_type       = RET_INTEGER,
1098         .arg1_type      = ARG_ANYTHING,
1099 };
1100
1101 const struct bpf_func_proto *
1102 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1103 {
1104         switch (func_id) {
1105         case BPF_FUNC_map_lookup_elem:
1106                 return &bpf_map_lookup_elem_proto;
1107         case BPF_FUNC_map_update_elem:
1108                 return &bpf_map_update_elem_proto;
1109         case BPF_FUNC_map_delete_elem:
1110                 return &bpf_map_delete_elem_proto;
1111         case BPF_FUNC_map_push_elem:
1112                 return &bpf_map_push_elem_proto;
1113         case BPF_FUNC_map_pop_elem:
1114                 return &bpf_map_pop_elem_proto;
1115         case BPF_FUNC_map_peek_elem:
1116                 return &bpf_map_peek_elem_proto;
1117         case BPF_FUNC_ktime_get_ns:
1118                 return &bpf_ktime_get_ns_proto;
1119         case BPF_FUNC_ktime_get_boot_ns:
1120                 return &bpf_ktime_get_boot_ns_proto;
1121         case BPF_FUNC_tail_call:
1122                 return &bpf_tail_call_proto;
1123         case BPF_FUNC_get_current_pid_tgid:
1124                 return &bpf_get_current_pid_tgid_proto;
1125         case BPF_FUNC_get_current_task:
1126                 return &bpf_get_current_task_proto;
1127         case BPF_FUNC_get_current_uid_gid:
1128                 return &bpf_get_current_uid_gid_proto;
1129         case BPF_FUNC_get_current_comm:
1130                 return &bpf_get_current_comm_proto;
1131         case BPF_FUNC_trace_printk:
1132                 return bpf_get_trace_printk_proto();
1133         case BPF_FUNC_get_smp_processor_id:
1134                 return &bpf_get_smp_processor_id_proto;
1135         case BPF_FUNC_get_numa_node_id:
1136                 return &bpf_get_numa_node_id_proto;
1137         case BPF_FUNC_perf_event_read:
1138                 return &bpf_perf_event_read_proto;
1139         case BPF_FUNC_probe_write_user:
1140                 return bpf_get_probe_write_proto();
1141         case BPF_FUNC_current_task_under_cgroup:
1142                 return &bpf_current_task_under_cgroup_proto;
1143         case BPF_FUNC_get_prandom_u32:
1144                 return &bpf_get_prandom_u32_proto;
1145         case BPF_FUNC_probe_read_user:
1146                 return &bpf_probe_read_user_proto;
1147         case BPF_FUNC_probe_read_kernel:
1148                 return &bpf_probe_read_kernel_proto;
1149         case BPF_FUNC_probe_read_user_str:
1150                 return &bpf_probe_read_user_str_proto;
1151         case BPF_FUNC_probe_read_kernel_str:
1152                 return &bpf_probe_read_kernel_str_proto;
1153 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1154         case BPF_FUNC_probe_read:
1155                 return &bpf_probe_read_compat_proto;
1156         case BPF_FUNC_probe_read_str:
1157                 return &bpf_probe_read_compat_str_proto;
1158 #endif
1159 #ifdef CONFIG_CGROUPS
1160         case BPF_FUNC_get_current_cgroup_id:
1161                 return &bpf_get_current_cgroup_id_proto;
1162 #endif
1163         case BPF_FUNC_send_signal:
1164                 return &bpf_send_signal_proto;
1165         case BPF_FUNC_send_signal_thread:
1166                 return &bpf_send_signal_thread_proto;
1167         case BPF_FUNC_perf_event_read_value:
1168                 return &bpf_perf_event_read_value_proto;
1169         case BPF_FUNC_get_ns_current_pid_tgid:
1170                 return &bpf_get_ns_current_pid_tgid_proto;
1171         case BPF_FUNC_ringbuf_output:
1172                 return &bpf_ringbuf_output_proto;
1173         case BPF_FUNC_ringbuf_reserve:
1174                 return &bpf_ringbuf_reserve_proto;
1175         case BPF_FUNC_ringbuf_submit:
1176                 return &bpf_ringbuf_submit_proto;
1177         case BPF_FUNC_ringbuf_discard:
1178                 return &bpf_ringbuf_discard_proto;
1179         case BPF_FUNC_ringbuf_query:
1180                 return &bpf_ringbuf_query_proto;
1181         case BPF_FUNC_jiffies64:
1182                 return &bpf_jiffies64_proto;
1183         case BPF_FUNC_get_task_stack:
1184                 return &bpf_get_task_stack_proto;
1185         default:
1186                 return NULL;
1187         }
1188 }
1189
1190 static const struct bpf_func_proto *
1191 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1192 {
1193         switch (func_id) {
1194         case BPF_FUNC_perf_event_output:
1195                 return &bpf_perf_event_output_proto;
1196         case BPF_FUNC_get_stackid:
1197                 return &bpf_get_stackid_proto;
1198         case BPF_FUNC_get_stack:
1199                 return &bpf_get_stack_proto;
1200 #ifdef CONFIG_BPF_KPROBE_OVERRIDE
1201         case BPF_FUNC_override_return:
1202                 return &bpf_override_return_proto;
1203 #endif
1204         default:
1205                 return bpf_tracing_func_proto(func_id, prog);
1206         }
1207 }
1208
1209 /* bpf+kprobe programs can access fields of 'struct pt_regs' */
1210 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
1211                                         const struct bpf_prog *prog,
1212                                         struct bpf_insn_access_aux *info)
1213 {
1214         if (off < 0 || off >= sizeof(struct pt_regs))
1215                 return false;
1216         if (type != BPF_READ)
1217                 return false;
1218         if (off % size != 0)
1219                 return false;
1220         /*
1221          * Assertion for 32 bit to make sure last 8 byte access
1222          * (BPF_DW) to the last 4 byte member is disallowed.
1223          */
1224         if (off + size > sizeof(struct pt_regs))
1225                 return false;
1226
1227         return true;
1228 }
1229
1230 const struct bpf_verifier_ops kprobe_verifier_ops = {
1231         .get_func_proto  = kprobe_prog_func_proto,
1232         .is_valid_access = kprobe_prog_is_valid_access,
1233 };
1234
1235 const struct bpf_prog_ops kprobe_prog_ops = {
1236 };
1237
1238 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
1239            u64, flags, void *, data, u64, size)
1240 {
1241         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
1242
1243         /*
1244          * r1 points to perf tracepoint buffer where first 8 bytes are hidden
1245          * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it
1246          * from there and call the same bpf_perf_event_output() helper inline.
1247          */
1248         return ____bpf_perf_event_output(regs, map, flags, data, size);
1249 }
1250
1251 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
1252         .func           = bpf_perf_event_output_tp,
1253         .gpl_only       = true,
1254         .ret_type       = RET_INTEGER,
1255         .arg1_type      = ARG_PTR_TO_CTX,
1256         .arg2_type      = ARG_CONST_MAP_PTR,
1257         .arg3_type      = ARG_ANYTHING,
1258         .arg4_type      = ARG_PTR_TO_MEM,
1259         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
1260 };
1261
1262 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
1263            u64, flags)
1264 {
1265         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
1266
1267         /*
1268          * Same comment as in bpf_perf_event_output_tp(), only that this time
1269          * the other helper's function body cannot be inlined due to being
1270          * external, thus we need to call raw helper function.
1271          */
1272         return bpf_get_stackid((unsigned long) regs, (unsigned long) map,
1273                                flags, 0, 0);
1274 }
1275
1276 static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
1277         .func           = bpf_get_stackid_tp,
1278         .gpl_only       = true,
1279         .ret_type       = RET_INTEGER,
1280         .arg1_type      = ARG_PTR_TO_CTX,
1281         .arg2_type      = ARG_CONST_MAP_PTR,
1282         .arg3_type      = ARG_ANYTHING,
1283 };
1284
1285 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size,
1286            u64, flags)
1287 {
1288         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
1289
1290         return bpf_get_stack((unsigned long) regs, (unsigned long) buf,
1291                              (unsigned long) size, flags, 0);
1292 }
1293
1294 static const struct bpf_func_proto bpf_get_stack_proto_tp = {
1295         .func           = bpf_get_stack_tp,
1296         .gpl_only       = true,
1297         .ret_type       = RET_INTEGER,
1298         .arg1_type      = ARG_PTR_TO_CTX,
1299         .arg2_type      = ARG_PTR_TO_UNINIT_MEM,
1300         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
1301         .arg4_type      = ARG_ANYTHING,
1302 };
1303
1304 static const struct bpf_func_proto *
1305 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1306 {
1307         switch (func_id) {
1308         case BPF_FUNC_perf_event_output:
1309                 return &bpf_perf_event_output_proto_tp;
1310         case BPF_FUNC_get_stackid:
1311                 return &bpf_get_stackid_proto_tp;
1312         case BPF_FUNC_get_stack:
1313                 return &bpf_get_stack_proto_tp;
1314         default:
1315                 return bpf_tracing_func_proto(func_id, prog);
1316         }
1317 }
1318
1319 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,
1320                                     const struct bpf_prog *prog,
1321                                     struct bpf_insn_access_aux *info)
1322 {
1323         if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
1324                 return false;
1325         if (type != BPF_READ)
1326                 return false;
1327         if (off % size != 0)
1328                 return false;
1329
1330         BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64));
1331         return true;
1332 }
1333
1334 const struct bpf_verifier_ops tracepoint_verifier_ops = {
1335         .get_func_proto  = tp_prog_func_proto,
1336         .is_valid_access = tp_prog_is_valid_access,
1337 };
1338
1339 const struct bpf_prog_ops tracepoint_prog_ops = {
1340 };
1341
1342 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx,
1343            struct bpf_perf_event_value *, buf, u32, size)
1344 {
1345         int err = -EINVAL;
1346
1347         if (unlikely(size != sizeof(struct bpf_perf_event_value)))
1348                 goto clear;
1349         err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
1350                                     &buf->running);
1351         if (unlikely(err))
1352                 goto clear;
1353         return 0;
1354 clear:
1355         memset(buf, 0, size);
1356         return err;
1357 }
1358
1359 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = {
1360          .func           = bpf_perf_prog_read_value,
1361          .gpl_only       = true,
1362          .ret_type       = RET_INTEGER,
1363          .arg1_type      = ARG_PTR_TO_CTX,
1364          .arg2_type      = ARG_PTR_TO_UNINIT_MEM,
1365          .arg3_type      = ARG_CONST_SIZE,
1366 };
1367
1368 BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx,
1369            void *, buf, u32, size, u64, flags)
1370 {
1371 #ifndef CONFIG_X86
1372         return -ENOENT;
1373 #else
1374         static const u32 br_entry_size = sizeof(struct perf_branch_entry);
1375         struct perf_branch_stack *br_stack = ctx->data->br_stack;
1376         u32 to_copy;
1377
1378         if (unlikely(flags & ~BPF_F_GET_BRANCH_RECORDS_SIZE))
1379                 return -EINVAL;
1380
1381         if (unlikely(!br_stack))
1382                 return -EINVAL;
1383
1384         if (flags & BPF_F_GET_BRANCH_RECORDS_SIZE)
1385                 return br_stack->nr * br_entry_size;
1386
1387         if (!buf || (size % br_entry_size != 0))
1388                 return -EINVAL;
1389
1390         to_copy = min_t(u32, br_stack->nr * br_entry_size, size);
1391         memcpy(buf, br_stack->entries, to_copy);
1392
1393         return to_copy;
1394 #endif
1395 }
1396
1397 static const struct bpf_func_proto bpf_read_branch_records_proto = {
1398         .func           = bpf_read_branch_records,
1399         .gpl_only       = true,
1400         .ret_type       = RET_INTEGER,
1401         .arg1_type      = ARG_PTR_TO_CTX,
1402         .arg2_type      = ARG_PTR_TO_MEM_OR_NULL,
1403         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
1404         .arg4_type      = ARG_ANYTHING,
1405 };
1406
1407 static const struct bpf_func_proto *
1408 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1409 {
1410         switch (func_id) {
1411         case BPF_FUNC_perf_event_output:
1412                 return &bpf_perf_event_output_proto_tp;
1413         case BPF_FUNC_get_stackid:
1414                 return &bpf_get_stackid_proto_pe;
1415         case BPF_FUNC_get_stack:
1416                 return &bpf_get_stack_proto_pe;
1417         case BPF_FUNC_perf_prog_read_value:
1418                 return &bpf_perf_prog_read_value_proto;
1419         case BPF_FUNC_read_branch_records:
1420                 return &bpf_read_branch_records_proto;
1421         default:
1422                 return bpf_tracing_func_proto(func_id, prog);
1423         }
1424 }
1425
1426 /*
1427  * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp
1428  * to avoid potential recursive reuse issue when/if tracepoints are added
1429  * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack.
1430  *
1431  * Since raw tracepoints run despite bpf_prog_active, support concurrent usage
1432  * in normal, irq, and nmi context.
1433  */
1434 struct bpf_raw_tp_regs {
1435         struct pt_regs regs[3];
1436 };
1437 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs);
1438 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level);
1439 static struct pt_regs *get_bpf_raw_tp_regs(void)
1440 {
1441         struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs);
1442         int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level);
1443
1444         if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) {
1445                 this_cpu_dec(bpf_raw_tp_nest_level);
1446                 return ERR_PTR(-EBUSY);
1447         }
1448
1449         return &tp_regs->regs[nest_level - 1];
1450 }
1451
1452 static void put_bpf_raw_tp_regs(void)
1453 {
1454         this_cpu_dec(bpf_raw_tp_nest_level);
1455 }
1456
1457 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args,
1458            struct bpf_map *, map, u64, flags, void *, data, u64, size)
1459 {
1460         struct pt_regs *regs = get_bpf_raw_tp_regs();
1461         int ret;
1462
1463         if (IS_ERR(regs))
1464                 return PTR_ERR(regs);
1465
1466         perf_fetch_caller_regs(regs);
1467         ret = ____bpf_perf_event_output(regs, map, flags, data, size);
1468
1469         put_bpf_raw_tp_regs();
1470         return ret;
1471 }
1472
1473 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = {
1474         .func           = bpf_perf_event_output_raw_tp,
1475         .gpl_only       = true,
1476         .ret_type       = RET_INTEGER,
1477         .arg1_type      = ARG_PTR_TO_CTX,
1478         .arg2_type      = ARG_CONST_MAP_PTR,
1479         .arg3_type      = ARG_ANYTHING,
1480         .arg4_type      = ARG_PTR_TO_MEM,
1481         .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
1482 };
1483
1484 extern const struct bpf_func_proto bpf_skb_output_proto;
1485 extern const struct bpf_func_proto bpf_xdp_output_proto;
1486
1487 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args,
1488            struct bpf_map *, map, u64, flags)
1489 {
1490         struct pt_regs *regs = get_bpf_raw_tp_regs();
1491         int ret;
1492
1493         if (IS_ERR(regs))
1494                 return PTR_ERR(regs);
1495
1496         perf_fetch_caller_regs(regs);
1497         /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */
1498         ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map,
1499                               flags, 0, 0);
1500         put_bpf_raw_tp_regs();
1501         return ret;
1502 }
1503
1504 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = {
1505         .func           = bpf_get_stackid_raw_tp,
1506         .gpl_only       = true,
1507         .ret_type       = RET_INTEGER,
1508         .arg1_type      = ARG_PTR_TO_CTX,
1509         .arg2_type      = ARG_CONST_MAP_PTR,
1510         .arg3_type      = ARG_ANYTHING,
1511 };
1512
1513 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args,
1514            void *, buf, u32, size, u64, flags)
1515 {
1516         struct pt_regs *regs = get_bpf_raw_tp_regs();
1517         int ret;
1518
1519         if (IS_ERR(regs))
1520                 return PTR_ERR(regs);
1521
1522         perf_fetch_caller_regs(regs);
1523         ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf,
1524                             (unsigned long) size, flags, 0);
1525         put_bpf_raw_tp_regs();
1526         return ret;
1527 }
1528
1529 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = {
1530         .func           = bpf_get_stack_raw_tp,
1531         .gpl_only       = true,
1532         .ret_type       = RET_INTEGER,
1533         .arg1_type      = ARG_PTR_TO_CTX,
1534         .arg2_type      = ARG_PTR_TO_MEM,
1535         .arg3_type      = ARG_CONST_SIZE_OR_ZERO,
1536         .arg4_type      = ARG_ANYTHING,
1537 };
1538
1539 static const struct bpf_func_proto *
1540 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1541 {
1542         switch (func_id) {
1543         case BPF_FUNC_perf_event_output:
1544                 return &bpf_perf_event_output_proto_raw_tp;
1545         case BPF_FUNC_get_stackid:
1546                 return &bpf_get_stackid_proto_raw_tp;
1547         case BPF_FUNC_get_stack:
1548                 return &bpf_get_stack_proto_raw_tp;
1549         default:
1550                 return bpf_tracing_func_proto(func_id, prog);
1551         }
1552 }
1553
1554 const struct bpf_func_proto *
1555 tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1556 {
1557         switch (func_id) {
1558 #ifdef CONFIG_NET
1559         case BPF_FUNC_skb_output:
1560                 return &bpf_skb_output_proto;
1561         case BPF_FUNC_xdp_output:
1562                 return &bpf_xdp_output_proto;
1563         case BPF_FUNC_skc_to_tcp6_sock:
1564                 return &bpf_skc_to_tcp6_sock_proto;
1565         case BPF_FUNC_skc_to_tcp_sock:
1566                 return &bpf_skc_to_tcp_sock_proto;
1567         case BPF_FUNC_skc_to_tcp_timewait_sock:
1568                 return &bpf_skc_to_tcp_timewait_sock_proto;
1569         case BPF_FUNC_skc_to_tcp_request_sock:
1570                 return &bpf_skc_to_tcp_request_sock_proto;
1571         case BPF_FUNC_skc_to_udp6_sock:
1572                 return &bpf_skc_to_udp6_sock_proto;
1573 #endif
1574         case BPF_FUNC_seq_printf:
1575                 return prog->expected_attach_type == BPF_TRACE_ITER ?
1576                        &bpf_seq_printf_proto :
1577                        NULL;
1578         case BPF_FUNC_seq_write:
1579                 return prog->expected_attach_type == BPF_TRACE_ITER ?
1580                        &bpf_seq_write_proto :
1581                        NULL;
1582         default:
1583                 return raw_tp_prog_func_proto(func_id, prog);
1584         }
1585 }
1586
1587 static bool raw_tp_prog_is_valid_access(int off, int size,
1588                                         enum bpf_access_type type,
1589                                         const struct bpf_prog *prog,
1590                                         struct bpf_insn_access_aux *info)
1591 {
1592         if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
1593                 return false;
1594         if (type != BPF_READ)
1595                 return false;
1596         if (off % size != 0)
1597                 return false;
1598         return true;
1599 }
1600
1601 static bool tracing_prog_is_valid_access(int off, int size,
1602                                          enum bpf_access_type type,
1603                                          const struct bpf_prog *prog,
1604                                          struct bpf_insn_access_aux *info)
1605 {
1606         if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
1607                 return false;
1608         if (type != BPF_READ)
1609                 return false;
1610         if (off % size != 0)
1611                 return false;
1612         return btf_ctx_access(off, size, type, prog, info);
1613 }
1614
1615 int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog,
1616                                      const union bpf_attr *kattr,
1617                                      union bpf_attr __user *uattr)
1618 {
1619         return -ENOTSUPP;
1620 }
1621
1622 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
1623         .get_func_proto  = raw_tp_prog_func_proto,
1624         .is_valid_access = raw_tp_prog_is_valid_access,
1625 };
1626
1627 const struct bpf_prog_ops raw_tracepoint_prog_ops = {
1628 };
1629
1630 const struct bpf_verifier_ops tracing_verifier_ops = {
1631         .get_func_proto  = tracing_prog_func_proto,
1632         .is_valid_access = tracing_prog_is_valid_access,
1633 };
1634
1635 const struct bpf_prog_ops tracing_prog_ops = {
1636         .test_run = bpf_prog_test_run_tracing,
1637 };
1638
1639 static bool raw_tp_writable_prog_is_valid_access(int off, int size,
1640                                                  enum bpf_access_type type,
1641                                                  const struct bpf_prog *prog,
1642                                                  struct bpf_insn_access_aux *info)
1643 {
1644         if (off == 0) {
1645                 if (size != sizeof(u64) || type != BPF_READ)
1646                         return false;
1647                 info->reg_type = PTR_TO_TP_BUFFER;
1648         }
1649         return raw_tp_prog_is_valid_access(off, size, type, prog, info);
1650 }
1651
1652 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = {
1653         .get_func_proto  = raw_tp_prog_func_proto,
1654         .is_valid_access = raw_tp_writable_prog_is_valid_access,
1655 };
1656
1657 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = {
1658 };
1659
1660 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
1661                                     const struct bpf_prog *prog,
1662                                     struct bpf_insn_access_aux *info)
1663 {
1664         const int size_u64 = sizeof(u64);
1665
1666         if (off < 0 || off >= sizeof(struct bpf_perf_event_data))
1667                 return false;
1668         if (type != BPF_READ)
1669                 return false;
1670         if (off % size != 0) {
1671                 if (sizeof(unsigned long) != 4)
1672                         return false;
1673                 if (size != 8)
1674                         return false;
1675                 if (off % size != 4)
1676                         return false;
1677         }
1678
1679         switch (off) {
1680         case bpf_ctx_range(struct bpf_perf_event_data, sample_period):
1681                 bpf_ctx_record_field_size(info, size_u64);
1682                 if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
1683                         return false;
1684                 break;
1685         case bpf_ctx_range(struct bpf_perf_event_data, addr):
1686                 bpf_ctx_record_field_size(info, size_u64);
1687                 if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
1688                         return false;
1689                 break;
1690         default:
1691                 if (size != sizeof(long))
1692                         return false;
1693         }
1694
1695         return true;
1696 }
1697
1698 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
1699                                       const struct bpf_insn *si,
1700                                       struct bpf_insn *insn_buf,
1701                                       struct bpf_prog *prog, u32 *target_size)
1702 {
1703         struct bpf_insn *insn = insn_buf;
1704
1705         switch (si->off) {
1706         case offsetof(struct bpf_perf_event_data, sample_period):
1707                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
1708                                                        data), si->dst_reg, si->src_reg,
1709                                       offsetof(struct bpf_perf_event_data_kern, data));
1710                 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
1711                                       bpf_target_off(struct perf_sample_data, period, 8,
1712                                                      target_size));
1713                 break;
1714         case offsetof(struct bpf_perf_event_data, addr):
1715                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
1716                                                        data), si->dst_reg, si->src_reg,
1717                                       offsetof(struct bpf_perf_event_data_kern, data));
1718                 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
1719                                       bpf_target_off(struct perf_sample_data, addr, 8,
1720                                                      target_size));
1721                 break;
1722         default:
1723                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
1724                                                        regs), si->dst_reg, si->src_reg,
1725                                       offsetof(struct bpf_perf_event_data_kern, regs));
1726                 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg,
1727                                       si->off);
1728                 break;
1729         }
1730
1731         return insn - insn_buf;
1732 }
1733
1734 const struct bpf_verifier_ops perf_event_verifier_ops = {
1735         .get_func_proto         = pe_prog_func_proto,
1736         .is_valid_access        = pe_prog_is_valid_access,
1737         .convert_ctx_access     = pe_prog_convert_ctx_access,
1738 };
1739
1740 const struct bpf_prog_ops perf_event_prog_ops = {
1741 };
1742
1743 static DEFINE_MUTEX(bpf_event_mutex);
1744
1745 #define BPF_TRACE_MAX_PROGS 64
1746
1747 int perf_event_attach_bpf_prog(struct perf_event *event,
1748                                struct bpf_prog *prog)
1749 {
1750         struct bpf_prog_array *old_array;
1751         struct bpf_prog_array *new_array;
1752         int ret = -EEXIST;
1753
1754         /*
1755          * Kprobe override only works if they are on the function entry,
1756          * and only if they are on the opt-in list.
1757          */
1758         if (prog->kprobe_override &&
1759             (!trace_kprobe_on_func_entry(event->tp_event) ||
1760              !trace_kprobe_error_injectable(event->tp_event)))
1761                 return -EINVAL;
1762
1763         mutex_lock(&bpf_event_mutex);
1764
1765         if (event->prog)
1766                 goto unlock;
1767
1768         old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);
1769         if (old_array &&
1770             bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) {
1771                 ret = -E2BIG;
1772                 goto unlock;
1773         }
1774
1775         ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array);
1776         if (ret < 0)
1777                 goto unlock;
1778
1779         /* set the new array to event->tp_event and set event->prog */
1780         event->prog = prog;
1781         rcu_assign_pointer(event->tp_event->prog_array, new_array);
1782         bpf_prog_array_free(old_array);
1783
1784 unlock:
1785         mutex_unlock(&bpf_event_mutex);
1786         return ret;
1787 }
1788
1789 void perf_event_detach_bpf_prog(struct perf_event *event)
1790 {
1791         struct bpf_prog_array *old_array;
1792         struct bpf_prog_array *new_array;
1793         int ret;
1794
1795         mutex_lock(&bpf_event_mutex);
1796
1797         if (!event->prog)
1798                 goto unlock;
1799
1800         old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);
1801         ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array);
1802         if (ret == -ENOENT)
1803                 goto unlock;
1804         if (ret < 0) {
1805                 bpf_prog_array_delete_safe(old_array, event->prog);
1806         } else {
1807                 rcu_assign_pointer(event->tp_event->prog_array, new_array);
1808                 bpf_prog_array_free(old_array);
1809         }
1810
1811         bpf_prog_put(event->prog);
1812         event->prog = NULL;
1813
1814 unlock:
1815         mutex_unlock(&bpf_event_mutex);
1816 }
1817
1818 int perf_event_query_prog_array(struct perf_event *event, void __user *info)
1819 {
1820         struct perf_event_query_bpf __user *uquery = info;
1821         struct perf_event_query_bpf query = {};
1822         struct bpf_prog_array *progs;
1823         u32 *ids, prog_cnt, ids_len;
1824         int ret;
1825
1826         if (!perfmon_capable())
1827                 return -EPERM;
1828         if (event->attr.type != PERF_TYPE_TRACEPOINT)
1829                 return -EINVAL;
1830         if (copy_from_user(&query, uquery, sizeof(query)))
1831                 return -EFAULT;
1832
1833         ids_len = query.ids_len;
1834         if (ids_len > BPF_TRACE_MAX_PROGS)
1835                 return -E2BIG;
1836         ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN);
1837         if (!ids)
1838                 return -ENOMEM;
1839         /*
1840          * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which
1841          * is required when user only wants to check for uquery->prog_cnt.
1842          * There is no need to check for it since the case is handled
1843          * gracefully in bpf_prog_array_copy_info.
1844          */
1845
1846         mutex_lock(&bpf_event_mutex);
1847         progs = bpf_event_rcu_dereference(event->tp_event->prog_array);
1848         ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt);
1849         mutex_unlock(&bpf_event_mutex);
1850
1851         if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) ||
1852             copy_to_user(uquery->ids, ids, ids_len * sizeof(u32)))
1853                 ret = -EFAULT;
1854
1855         kfree(ids);
1856         return ret;
1857 }
1858
1859 extern struct bpf_raw_event_map __start__bpf_raw_tp[];
1860 extern struct bpf_raw_event_map __stop__bpf_raw_tp[];
1861
1862 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name)
1863 {
1864         struct bpf_raw_event_map *btp = __start__bpf_raw_tp;
1865
1866         for (; btp < __stop__bpf_raw_tp; btp++) {
1867                 if (!strcmp(btp->tp->name, name))
1868                         return btp;
1869         }
1870
1871         return bpf_get_raw_tracepoint_module(name);
1872 }
1873
1874 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
1875 {
1876         struct module *mod = __module_address((unsigned long)btp);
1877
1878         if (mod)
1879                 module_put(mod);
1880 }
1881
1882 static __always_inline
1883 void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
1884 {
1885         cant_sleep();
1886         rcu_read_lock();
1887         (void) BPF_PROG_RUN(prog, args);
1888         rcu_read_unlock();
1889 }
1890
1891 #define UNPACK(...)                     __VA_ARGS__
1892 #define REPEAT_1(FN, DL, X, ...)        FN(X)
1893 #define REPEAT_2(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__)
1894 #define REPEAT_3(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__)
1895 #define REPEAT_4(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__)
1896 #define REPEAT_5(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__)
1897 #define REPEAT_6(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__)
1898 #define REPEAT_7(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__)
1899 #define REPEAT_8(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__)
1900 #define REPEAT_9(FN, DL, X, ...)        FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__)
1901 #define REPEAT_10(FN, DL, X, ...)       FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__)
1902 #define REPEAT_11(FN, DL, X, ...)       FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__)
1903 #define REPEAT_12(FN, DL, X, ...)       FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__)
1904 #define REPEAT(X, FN, DL, ...)          REPEAT_##X(FN, DL, __VA_ARGS__)
1905
1906 #define SARG(X)         u64 arg##X
1907 #define COPY(X)         args[X] = arg##X
1908
1909 #define __DL_COM        (,)
1910 #define __DL_SEM        (;)
1911
1912 #define __SEQ_0_11      0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
1913
1914 #define BPF_TRACE_DEFN_x(x)                                             \
1915         void bpf_trace_run##x(struct bpf_prog *prog,                    \
1916                               REPEAT(x, SARG, __DL_COM, __SEQ_0_11))    \
1917         {                                                               \
1918                 u64 args[x];                                            \
1919                 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11);                  \
1920                 __bpf_trace_run(prog, args);                            \
1921         }                                                               \
1922         EXPORT_SYMBOL_GPL(bpf_trace_run##x)
1923 BPF_TRACE_DEFN_x(1);
1924 BPF_TRACE_DEFN_x(2);
1925 BPF_TRACE_DEFN_x(3);
1926 BPF_TRACE_DEFN_x(4);
1927 BPF_TRACE_DEFN_x(5);
1928 BPF_TRACE_DEFN_x(6);
1929 BPF_TRACE_DEFN_x(7);
1930 BPF_TRACE_DEFN_x(8);
1931 BPF_TRACE_DEFN_x(9);
1932 BPF_TRACE_DEFN_x(10);
1933 BPF_TRACE_DEFN_x(11);
1934 BPF_TRACE_DEFN_x(12);
1935
1936 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
1937 {
1938         struct tracepoint *tp = btp->tp;
1939
1940         /*
1941          * check that program doesn't access arguments beyond what's
1942          * available in this tracepoint
1943          */
1944         if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64))
1945                 return -EINVAL;
1946
1947         if (prog->aux->max_tp_access > btp->writable_size)
1948                 return -EINVAL;
1949
1950         return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog);
1951 }
1952
1953 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
1954 {
1955         return __bpf_probe_register(btp, prog);
1956 }
1957
1958 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
1959 {
1960         return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog);
1961 }
1962
1963 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
1964                             u32 *fd_type, const char **buf,
1965                             u64 *probe_offset, u64 *probe_addr)
1966 {
1967         bool is_tracepoint, is_syscall_tp;
1968         struct bpf_prog *prog;
1969         int flags, err = 0;
1970
1971         prog = event->prog;
1972         if (!prog)
1973                 return -ENOENT;
1974
1975         /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */
1976         if (prog->type == BPF_PROG_TYPE_PERF_EVENT)
1977                 return -EOPNOTSUPP;
1978
1979         *prog_id = prog->aux->id;
1980         flags = event->tp_event->flags;
1981         is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT;
1982         is_syscall_tp = is_syscall_trace_event(event->tp_event);
1983
1984         if (is_tracepoint || is_syscall_tp) {
1985                 *buf = is_tracepoint ? event->tp_event->tp->name
1986                                      : event->tp_event->name;
1987                 *fd_type = BPF_FD_TYPE_TRACEPOINT;
1988                 *probe_offset = 0x0;
1989                 *probe_addr = 0x0;
1990         } else {
1991                 /* kprobe/uprobe */
1992                 err = -EOPNOTSUPP;
1993 #ifdef CONFIG_KPROBE_EVENTS
1994                 if (flags & TRACE_EVENT_FL_KPROBE)
1995                         err = bpf_get_kprobe_info(event, fd_type, buf,
1996                                                   probe_offset, probe_addr,
1997                                                   event->attr.type == PERF_TYPE_TRACEPOINT);
1998 #endif
1999 #ifdef CONFIG_UPROBE_EVENTS
2000                 if (flags & TRACE_EVENT_FL_UPROBE)
2001                         err = bpf_get_uprobe_info(event, fd_type, buf,
2002                                                   probe_offset,
2003                                                   event->attr.type == PERF_TYPE_TRACEPOINT);
2004 #endif
2005         }
2006
2007         return err;
2008 }
2009
2010 static int __init send_signal_irq_work_init(void)
2011 {
2012         int cpu;
2013         struct send_signal_irq_work *work;
2014
2015         for_each_possible_cpu(cpu) {
2016                 work = per_cpu_ptr(&send_signal_work, cpu);
2017                 init_irq_work(&work->irq_work, do_bpf_send_signal);
2018         }
2019         return 0;
2020 }
2021
2022 subsys_initcall(send_signal_irq_work_init);
2023
2024 #ifdef CONFIG_MODULES
2025 static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
2026                             void *module)
2027 {
2028         struct bpf_trace_module *btm, *tmp;
2029         struct module *mod = module;
2030
2031         if (mod->num_bpf_raw_events == 0 ||
2032             (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
2033                 return 0;
2034
2035         mutex_lock(&bpf_module_mutex);
2036
2037         switch (op) {
2038         case MODULE_STATE_COMING:
2039                 btm = kzalloc(sizeof(*btm), GFP_KERNEL);
2040                 if (btm) {
2041                         btm->module = module;
2042                         list_add(&btm->list, &bpf_trace_modules);
2043                 }
2044                 break;
2045         case MODULE_STATE_GOING:
2046                 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) {
2047                         if (btm->module == module) {
2048                                 list_del(&btm->list);
2049                                 kfree(btm);
2050                                 break;
2051                         }
2052                 }
2053                 break;
2054         }
2055
2056         mutex_unlock(&bpf_module_mutex);
2057
2058         return 0;
2059 }
2060
2061 static struct notifier_block bpf_module_nb = {
2062         .notifier_call = bpf_event_notify,
2063 };
2064
2065 static int __init bpf_event_init(void)
2066 {
2067         register_module_notifier(&bpf_module_nb);
2068         return 0;
2069 }
2070
2071 fs_initcall(bpf_event_init);
2072 #endif /* CONFIG_MODULES */