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_verifier.h> 10 #include <linux/bpf_perf_event.h> 11 #include <linux/btf.h> 12 #include <linux/filter.h> 13 #include <linux/uaccess.h> 14 #include <linux/ctype.h> 15 #include <linux/kprobes.h> 16 #include <linux/spinlock.h> 17 #include <linux/syscalls.h> 18 #include <linux/error-injection.h> 19 #include <linux/btf_ids.h> 20 #include <linux/bpf_lsm.h> 21 #include <linux/fprobe.h> 22 #include <linux/bsearch.h> 23 #include <linux/sort.h> 24 #include <linux/key.h> 25 #include <linux/verification.h> 26 #include <linux/namei.h> 27 28 #include <net/bpf_sk_storage.h> 29 30 #include <uapi/linux/bpf.h> 31 #include <uapi/linux/btf.h> 32 33 #include <asm/tlb.h> 34 35 #include "trace_probe.h" 36 #include "trace.h" 37 38 #define CREATE_TRACE_POINTS 39 #include "bpf_trace.h" 40 41 #define bpf_event_rcu_dereference(p) \ 42 rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) 43 44 #define MAX_UPROBE_MULTI_CNT (1U << 20) 45 #define MAX_KPROBE_MULTI_CNT (1U << 20) 46 47 #ifdef CONFIG_MODULES 48 struct bpf_trace_module { 49 struct module *module; 50 struct list_head list; 51 }; 52 53 static LIST_HEAD(bpf_trace_modules); 54 static DEFINE_MUTEX(bpf_module_mutex); 55 56 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 57 { 58 struct bpf_raw_event_map *btp, *ret = NULL; 59 struct bpf_trace_module *btm; 60 unsigned int i; 61 62 mutex_lock(&bpf_module_mutex); 63 list_for_each_entry(btm, &bpf_trace_modules, list) { 64 for (i = 0; i < btm->module->num_bpf_raw_events; ++i) { 65 btp = &btm->module->bpf_raw_events[i]; 66 if (!strcmp(btp->tp->name, name)) { 67 if (try_module_get(btm->module)) 68 ret = btp; 69 goto out; 70 } 71 } 72 } 73 out: 74 mutex_unlock(&bpf_module_mutex); 75 return ret; 76 } 77 #else 78 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 79 { 80 return NULL; 81 } 82 #endif /* CONFIG_MODULES */ 83 84 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 85 u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 86 87 static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size, 88 u64 flags, const struct btf **btf, 89 s32 *btf_id); 90 static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx); 91 static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx); 92 93 static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx); 94 static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx); 95 96 /** 97 * trace_call_bpf - invoke BPF program 98 * @call: tracepoint event 99 * @ctx: opaque context pointer 100 * 101 * kprobe handlers execute BPF programs via this helper. 102 * Can be used from static tracepoints in the future. 103 * 104 * Return: BPF programs always return an integer which is interpreted by 105 * kprobe handler as: 106 * 0 - return from kprobe (event is filtered out) 107 * 1 - store kprobe event into ring buffer 108 * Other values are reserved and currently alias to 1 109 */ 110 unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) 111 { 112 unsigned int ret; 113 114 cant_sleep(); 115 116 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { 117 /* 118 * since some bpf program is already running on this cpu, 119 * don't call into another bpf program (same or different) 120 * and don't send kprobe event into ring-buffer, 121 * so return zero here 122 */ 123 ret = 0; 124 goto out; 125 } 126 127 /* 128 * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock 129 * to all call sites, we did a bpf_prog_array_valid() there to check 130 * whether call->prog_array is empty or not, which is 131 * a heuristic to speed up execution. 132 * 133 * If bpf_prog_array_valid() fetched prog_array was 134 * non-NULL, we go into trace_call_bpf() and do the actual 135 * proper rcu_dereference() under RCU lock. 136 * If it turns out that prog_array is NULL then, we bail out. 137 * For the opposite, if the bpf_prog_array_valid() fetched pointer 138 * was NULL, you'll skip the prog_array with the risk of missing 139 * out of events when it was updated in between this and the 140 * rcu_dereference() which is accepted risk. 141 */ 142 rcu_read_lock(); 143 ret = bpf_prog_run_array(rcu_dereference(call->prog_array), 144 ctx, bpf_prog_run); 145 rcu_read_unlock(); 146 147 out: 148 __this_cpu_dec(bpf_prog_active); 149 150 return ret; 151 } 152 153 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 154 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) 155 { 156 regs_set_return_value(regs, rc); 157 override_function_with_return(regs); 158 return 0; 159 } 160 161 static const struct bpf_func_proto bpf_override_return_proto = { 162 .func = bpf_override_return, 163 .gpl_only = true, 164 .ret_type = RET_INTEGER, 165 .arg1_type = ARG_PTR_TO_CTX, 166 .arg2_type = ARG_ANYTHING, 167 }; 168 #endif 169 170 static __always_inline int 171 bpf_probe_read_user_common(void *dst, u32 size, const void __user *unsafe_ptr) 172 { 173 int ret; 174 175 ret = copy_from_user_nofault(dst, unsafe_ptr, size); 176 if (unlikely(ret < 0)) 177 memset(dst, 0, size); 178 return ret; 179 } 180 181 BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size, 182 const void __user *, unsafe_ptr) 183 { 184 return bpf_probe_read_user_common(dst, size, unsafe_ptr); 185 } 186 187 const struct bpf_func_proto bpf_probe_read_user_proto = { 188 .func = bpf_probe_read_user, 189 .gpl_only = true, 190 .ret_type = RET_INTEGER, 191 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 192 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 193 .arg3_type = ARG_ANYTHING, 194 }; 195 196 static __always_inline int 197 bpf_probe_read_user_str_common(void *dst, u32 size, 198 const void __user *unsafe_ptr) 199 { 200 int ret; 201 202 /* 203 * NB: We rely on strncpy_from_user() not copying junk past the NUL 204 * terminator into `dst`. 205 * 206 * strncpy_from_user() does long-sized strides in the fast path. If the 207 * strncpy does not mask out the bytes after the NUL in `unsafe_ptr`, 208 * then there could be junk after the NUL in `dst`. If user takes `dst` 209 * and keys a hash map with it, then semantically identical strings can 210 * occupy multiple entries in the map. 211 */ 212 ret = strncpy_from_user_nofault(dst, unsafe_ptr, size); 213 if (unlikely(ret < 0)) 214 memset(dst, 0, size); 215 return ret; 216 } 217 218 BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size, 219 const void __user *, unsafe_ptr) 220 { 221 return bpf_probe_read_user_str_common(dst, size, unsafe_ptr); 222 } 223 224 const struct bpf_func_proto bpf_probe_read_user_str_proto = { 225 .func = bpf_probe_read_user_str, 226 .gpl_only = true, 227 .ret_type = RET_INTEGER, 228 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 229 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 230 .arg3_type = ARG_ANYTHING, 231 }; 232 233 BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size, 234 const void *, unsafe_ptr) 235 { 236 return bpf_probe_read_kernel_common(dst, size, unsafe_ptr); 237 } 238 239 const struct bpf_func_proto bpf_probe_read_kernel_proto = { 240 .func = bpf_probe_read_kernel, 241 .gpl_only = true, 242 .ret_type = RET_INTEGER, 243 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 244 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 245 .arg3_type = ARG_ANYTHING, 246 }; 247 248 static __always_inline int 249 bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr) 250 { 251 int ret; 252 253 /* 254 * The strncpy_from_kernel_nofault() call will likely not fill the 255 * entire buffer, but that's okay in this circumstance as we're probing 256 * arbitrary memory anyway similar to bpf_probe_read_*() and might 257 * as well probe the stack. Thus, memory is explicitly cleared 258 * only in error case, so that improper users ignoring return 259 * code altogether don't copy garbage; otherwise length of string 260 * is returned that can be used for bpf_perf_event_output() et al. 261 */ 262 ret = strncpy_from_kernel_nofault(dst, unsafe_ptr, size); 263 if (unlikely(ret < 0)) 264 memset(dst, 0, size); 265 return ret; 266 } 267 268 BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size, 269 const void *, unsafe_ptr) 270 { 271 return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr); 272 } 273 274 const struct bpf_func_proto bpf_probe_read_kernel_str_proto = { 275 .func = bpf_probe_read_kernel_str, 276 .gpl_only = true, 277 .ret_type = RET_INTEGER, 278 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 279 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 280 .arg3_type = ARG_ANYTHING, 281 }; 282 283 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 284 BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size, 285 const void *, unsafe_ptr) 286 { 287 if ((unsigned long)unsafe_ptr < TASK_SIZE) { 288 return bpf_probe_read_user_common(dst, size, 289 (__force void __user *)unsafe_ptr); 290 } 291 return bpf_probe_read_kernel_common(dst, size, unsafe_ptr); 292 } 293 294 static const struct bpf_func_proto bpf_probe_read_compat_proto = { 295 .func = bpf_probe_read_compat, 296 .gpl_only = true, 297 .ret_type = RET_INTEGER, 298 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 299 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 300 .arg3_type = ARG_ANYTHING, 301 }; 302 303 BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size, 304 const void *, unsafe_ptr) 305 { 306 if ((unsigned long)unsafe_ptr < TASK_SIZE) { 307 return bpf_probe_read_user_str_common(dst, size, 308 (__force void __user *)unsafe_ptr); 309 } 310 return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr); 311 } 312 313 static const struct bpf_func_proto bpf_probe_read_compat_str_proto = { 314 .func = bpf_probe_read_compat_str, 315 .gpl_only = true, 316 .ret_type = RET_INTEGER, 317 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 318 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 319 .arg3_type = ARG_ANYTHING, 320 }; 321 #endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */ 322 323 BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src, 324 u32, size) 325 { 326 /* 327 * Ensure we're in user context which is safe for the helper to 328 * run. This helper has no business in a kthread. 329 * 330 * access_ok() should prevent writing to non-user memory, but in 331 * some situations (nommu, temporary switch, etc) access_ok() does 332 * not provide enough validation, hence the check on KERNEL_DS. 333 * 334 * nmi_uaccess_okay() ensures the probe is not run in an interim 335 * state, when the task or mm are switched. This is specifically 336 * required to prevent the use of temporary mm. 337 */ 338 339 if (unlikely(in_interrupt() || 340 current->flags & (PF_KTHREAD | PF_EXITING))) 341 return -EPERM; 342 if (unlikely(!nmi_uaccess_okay())) 343 return -EPERM; 344 345 return copy_to_user_nofault(unsafe_ptr, src, size); 346 } 347 348 static const struct bpf_func_proto bpf_probe_write_user_proto = { 349 .func = bpf_probe_write_user, 350 .gpl_only = true, 351 .ret_type = RET_INTEGER, 352 .arg1_type = ARG_ANYTHING, 353 .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 354 .arg3_type = ARG_CONST_SIZE, 355 }; 356 357 static const struct bpf_func_proto *bpf_get_probe_write_proto(void) 358 { 359 if (!capable(CAP_SYS_ADMIN)) 360 return NULL; 361 362 pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", 363 current->comm, task_pid_nr(current)); 364 365 return &bpf_probe_write_user_proto; 366 } 367 368 #define MAX_TRACE_PRINTK_VARARGS 3 369 #define BPF_TRACE_PRINTK_SIZE 1024 370 371 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, 372 u64, arg2, u64, arg3) 373 { 374 u64 args[MAX_TRACE_PRINTK_VARARGS] = { arg1, arg2, arg3 }; 375 struct bpf_bprintf_data data = { 376 .get_bin_args = true, 377 .get_buf = true, 378 }; 379 int ret; 380 381 ret = bpf_bprintf_prepare(fmt, fmt_size, args, 382 MAX_TRACE_PRINTK_VARARGS, &data); 383 if (ret < 0) 384 return ret; 385 386 ret = bstr_printf(data.buf, MAX_BPRINTF_BUF, fmt, data.bin_args); 387 388 trace_bpf_trace_printk(data.buf); 389 390 bpf_bprintf_cleanup(&data); 391 392 return ret; 393 } 394 395 static const struct bpf_func_proto bpf_trace_printk_proto = { 396 .func = bpf_trace_printk, 397 .gpl_only = true, 398 .ret_type = RET_INTEGER, 399 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY, 400 .arg2_type = ARG_CONST_SIZE, 401 }; 402 403 static void __set_printk_clr_event(void) 404 { 405 /* 406 * This program might be calling bpf_trace_printk, 407 * so enable the associated bpf_trace/bpf_trace_printk event. 408 * Repeat this each time as it is possible a user has 409 * disabled bpf_trace_printk events. By loading a program 410 * calling bpf_trace_printk() however the user has expressed 411 * the intent to see such events. 412 */ 413 if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1)) 414 pr_warn_ratelimited("could not enable bpf_trace_printk events"); 415 } 416 417 const struct bpf_func_proto *bpf_get_trace_printk_proto(void) 418 { 419 __set_printk_clr_event(); 420 return &bpf_trace_printk_proto; 421 } 422 423 BPF_CALL_4(bpf_trace_vprintk, char *, fmt, u32, fmt_size, const void *, args, 424 u32, data_len) 425 { 426 struct bpf_bprintf_data data = { 427 .get_bin_args = true, 428 .get_buf = true, 429 }; 430 int ret, num_args; 431 432 if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 || 433 (data_len && !args)) 434 return -EINVAL; 435 num_args = data_len / 8; 436 437 ret = bpf_bprintf_prepare(fmt, fmt_size, args, num_args, &data); 438 if (ret < 0) 439 return ret; 440 441 ret = bstr_printf(data.buf, MAX_BPRINTF_BUF, fmt, data.bin_args); 442 443 trace_bpf_trace_printk(data.buf); 444 445 bpf_bprintf_cleanup(&data); 446 447 return ret; 448 } 449 450 static const struct bpf_func_proto bpf_trace_vprintk_proto = { 451 .func = bpf_trace_vprintk, 452 .gpl_only = true, 453 .ret_type = RET_INTEGER, 454 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY, 455 .arg2_type = ARG_CONST_SIZE, 456 .arg3_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY, 457 .arg4_type = ARG_CONST_SIZE_OR_ZERO, 458 }; 459 460 const struct bpf_func_proto *bpf_get_trace_vprintk_proto(void) 461 { 462 __set_printk_clr_event(); 463 return &bpf_trace_vprintk_proto; 464 } 465 466 BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, 467 const void *, args, u32, data_len) 468 { 469 struct bpf_bprintf_data data = { 470 .get_bin_args = true, 471 }; 472 int err, num_args; 473 474 if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 || 475 (data_len && !args)) 476 return -EINVAL; 477 num_args = data_len / 8; 478 479 err = bpf_bprintf_prepare(fmt, fmt_size, args, num_args, &data); 480 if (err < 0) 481 return err; 482 483 seq_bprintf(m, fmt, data.bin_args); 484 485 bpf_bprintf_cleanup(&data); 486 487 return seq_has_overflowed(m) ? -EOVERFLOW : 0; 488 } 489 490 BTF_ID_LIST_SINGLE(btf_seq_file_ids, struct, seq_file) 491 492 static const struct bpf_func_proto bpf_seq_printf_proto = { 493 .func = bpf_seq_printf, 494 .gpl_only = true, 495 .ret_type = RET_INTEGER, 496 .arg1_type = ARG_PTR_TO_BTF_ID, 497 .arg1_btf_id = &btf_seq_file_ids[0], 498 .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 499 .arg3_type = ARG_CONST_SIZE, 500 .arg4_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY, 501 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 502 }; 503 504 BPF_CALL_3(bpf_seq_write, struct seq_file *, m, const void *, data, u32, len) 505 { 506 return seq_write(m, data, len) ? -EOVERFLOW : 0; 507 } 508 509 static const struct bpf_func_proto bpf_seq_write_proto = { 510 .func = bpf_seq_write, 511 .gpl_only = true, 512 .ret_type = RET_INTEGER, 513 .arg1_type = ARG_PTR_TO_BTF_ID, 514 .arg1_btf_id = &btf_seq_file_ids[0], 515 .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 516 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 517 }; 518 519 BPF_CALL_4(bpf_seq_printf_btf, struct seq_file *, m, struct btf_ptr *, ptr, 520 u32, btf_ptr_size, u64, flags) 521 { 522 const struct btf *btf; 523 s32 btf_id; 524 int ret; 525 526 ret = bpf_btf_printf_prepare(ptr, btf_ptr_size, flags, &btf, &btf_id); 527 if (ret) 528 return ret; 529 530 return btf_type_seq_show_flags(btf, btf_id, ptr->ptr, m, flags); 531 } 532 533 static const struct bpf_func_proto bpf_seq_printf_btf_proto = { 534 .func = bpf_seq_printf_btf, 535 .gpl_only = true, 536 .ret_type = RET_INTEGER, 537 .arg1_type = ARG_PTR_TO_BTF_ID, 538 .arg1_btf_id = &btf_seq_file_ids[0], 539 .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 540 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 541 .arg4_type = ARG_ANYTHING, 542 }; 543 544 static __always_inline int 545 get_map_perf_counter(struct bpf_map *map, u64 flags, 546 u64 *value, u64 *enabled, u64 *running) 547 { 548 struct bpf_array *array = container_of(map, struct bpf_array, map); 549 unsigned int cpu = smp_processor_id(); 550 u64 index = flags & BPF_F_INDEX_MASK; 551 struct bpf_event_entry *ee; 552 553 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) 554 return -EINVAL; 555 if (index == BPF_F_CURRENT_CPU) 556 index = cpu; 557 if (unlikely(index >= array->map.max_entries)) 558 return -E2BIG; 559 560 ee = READ_ONCE(array->ptrs[index]); 561 if (!ee) 562 return -ENOENT; 563 564 return perf_event_read_local(ee->event, value, enabled, running); 565 } 566 567 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) 568 { 569 u64 value = 0; 570 int err; 571 572 err = get_map_perf_counter(map, flags, &value, NULL, NULL); 573 /* 574 * this api is ugly since we miss [-22..-2] range of valid 575 * counter values, but that's uapi 576 */ 577 if (err) 578 return err; 579 return value; 580 } 581 582 static const struct bpf_func_proto bpf_perf_event_read_proto = { 583 .func = bpf_perf_event_read, 584 .gpl_only = true, 585 .ret_type = RET_INTEGER, 586 .arg1_type = ARG_CONST_MAP_PTR, 587 .arg2_type = ARG_ANYTHING, 588 }; 589 590 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags, 591 struct bpf_perf_event_value *, buf, u32, size) 592 { 593 int err = -EINVAL; 594 595 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 596 goto clear; 597 err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled, 598 &buf->running); 599 if (unlikely(err)) 600 goto clear; 601 return 0; 602 clear: 603 memset(buf, 0, size); 604 return err; 605 } 606 607 static const struct bpf_func_proto bpf_perf_event_read_value_proto = { 608 .func = bpf_perf_event_read_value, 609 .gpl_only = true, 610 .ret_type = RET_INTEGER, 611 .arg1_type = ARG_CONST_MAP_PTR, 612 .arg2_type = ARG_ANYTHING, 613 .arg3_type = ARG_PTR_TO_UNINIT_MEM, 614 .arg4_type = ARG_CONST_SIZE, 615 }; 616 617 static __always_inline u64 618 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, 619 u64 flags, struct perf_raw_record *raw, 620 struct perf_sample_data *sd) 621 { 622 struct bpf_array *array = container_of(map, struct bpf_array, map); 623 unsigned int cpu = smp_processor_id(); 624 u64 index = flags & BPF_F_INDEX_MASK; 625 struct bpf_event_entry *ee; 626 struct perf_event *event; 627 628 if (index == BPF_F_CURRENT_CPU) 629 index = cpu; 630 if (unlikely(index >= array->map.max_entries)) 631 return -E2BIG; 632 633 ee = READ_ONCE(array->ptrs[index]); 634 if (!ee) 635 return -ENOENT; 636 637 event = ee->event; 638 if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || 639 event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) 640 return -EINVAL; 641 642 if (unlikely(event->oncpu != cpu)) 643 return -EOPNOTSUPP; 644 645 perf_sample_save_raw_data(sd, event, raw); 646 647 return perf_event_output(event, sd, regs); 648 } 649 650 /* 651 * Support executing tracepoints in normal, irq, and nmi context that each call 652 * bpf_perf_event_output 653 */ 654 struct bpf_trace_sample_data { 655 struct perf_sample_data sds[3]; 656 }; 657 658 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); 659 static DEFINE_PER_CPU(int, bpf_trace_nest_level); 660 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, 661 u64, flags, void *, data, u64, size) 662 { 663 struct bpf_trace_sample_data *sds; 664 struct perf_raw_record raw = { 665 .frag = { 666 .size = size, 667 .data = data, 668 }, 669 }; 670 struct perf_sample_data *sd; 671 int nest_level, err; 672 673 preempt_disable(); 674 sds = this_cpu_ptr(&bpf_trace_sds); 675 nest_level = this_cpu_inc_return(bpf_trace_nest_level); 676 677 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { 678 err = -EBUSY; 679 goto out; 680 } 681 682 sd = &sds->sds[nest_level - 1]; 683 684 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { 685 err = -EINVAL; 686 goto out; 687 } 688 689 perf_sample_data_init(sd, 0, 0); 690 691 err = __bpf_perf_event_output(regs, map, flags, &raw, sd); 692 out: 693 this_cpu_dec(bpf_trace_nest_level); 694 preempt_enable(); 695 return err; 696 } 697 698 static const struct bpf_func_proto bpf_perf_event_output_proto = { 699 .func = bpf_perf_event_output, 700 .gpl_only = true, 701 .ret_type = RET_INTEGER, 702 .arg1_type = ARG_PTR_TO_CTX, 703 .arg2_type = ARG_CONST_MAP_PTR, 704 .arg3_type = ARG_ANYTHING, 705 .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY, 706 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 707 }; 708 709 static DEFINE_PER_CPU(int, bpf_event_output_nest_level); 710 struct bpf_nested_pt_regs { 711 struct pt_regs regs[3]; 712 }; 713 static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs); 714 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds); 715 716 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 717 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 718 { 719 struct perf_raw_frag frag = { 720 .copy = ctx_copy, 721 .size = ctx_size, 722 .data = ctx, 723 }; 724 struct perf_raw_record raw = { 725 .frag = { 726 { 727 .next = ctx_size ? &frag : NULL, 728 }, 729 .size = meta_size, 730 .data = meta, 731 }, 732 }; 733 struct perf_sample_data *sd; 734 struct pt_regs *regs; 735 int nest_level; 736 u64 ret; 737 738 preempt_disable(); 739 nest_level = this_cpu_inc_return(bpf_event_output_nest_level); 740 741 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) { 742 ret = -EBUSY; 743 goto out; 744 } 745 sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]); 746 regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]); 747 748 perf_fetch_caller_regs(regs); 749 perf_sample_data_init(sd, 0, 0); 750 751 ret = __bpf_perf_event_output(regs, map, flags, &raw, sd); 752 out: 753 this_cpu_dec(bpf_event_output_nest_level); 754 preempt_enable(); 755 return ret; 756 } 757 758 BPF_CALL_0(bpf_get_current_task) 759 { 760 return (long) current; 761 } 762 763 const struct bpf_func_proto bpf_get_current_task_proto = { 764 .func = bpf_get_current_task, 765 .gpl_only = true, 766 .ret_type = RET_INTEGER, 767 }; 768 769 BPF_CALL_0(bpf_get_current_task_btf) 770 { 771 return (unsigned long) current; 772 } 773 774 const struct bpf_func_proto bpf_get_current_task_btf_proto = { 775 .func = bpf_get_current_task_btf, 776 .gpl_only = true, 777 .ret_type = RET_PTR_TO_BTF_ID_TRUSTED, 778 .ret_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], 779 }; 780 781 BPF_CALL_1(bpf_task_pt_regs, struct task_struct *, task) 782 { 783 return (unsigned long) task_pt_regs(task); 784 } 785 786 BTF_ID_LIST(bpf_task_pt_regs_ids) 787 BTF_ID(struct, pt_regs) 788 789 const struct bpf_func_proto bpf_task_pt_regs_proto = { 790 .func = bpf_task_pt_regs, 791 .gpl_only = true, 792 .arg1_type = ARG_PTR_TO_BTF_ID, 793 .arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], 794 .ret_type = RET_PTR_TO_BTF_ID, 795 .ret_btf_id = &bpf_task_pt_regs_ids[0], 796 }; 797 798 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) 799 { 800 struct bpf_array *array = container_of(map, struct bpf_array, map); 801 struct cgroup *cgrp; 802 803 if (unlikely(idx >= array->map.max_entries)) 804 return -E2BIG; 805 806 cgrp = READ_ONCE(array->ptrs[idx]); 807 if (unlikely(!cgrp)) 808 return -EAGAIN; 809 810 return task_under_cgroup_hierarchy(current, cgrp); 811 } 812 813 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { 814 .func = bpf_current_task_under_cgroup, 815 .gpl_only = false, 816 .ret_type = RET_INTEGER, 817 .arg1_type = ARG_CONST_MAP_PTR, 818 .arg2_type = ARG_ANYTHING, 819 }; 820 821 struct send_signal_irq_work { 822 struct irq_work irq_work; 823 struct task_struct *task; 824 u32 sig; 825 enum pid_type type; 826 }; 827 828 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); 829 830 static void do_bpf_send_signal(struct irq_work *entry) 831 { 832 struct send_signal_irq_work *work; 833 834 work = container_of(entry, struct send_signal_irq_work, irq_work); 835 group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type); 836 put_task_struct(work->task); 837 } 838 839 static int bpf_send_signal_common(u32 sig, enum pid_type type) 840 { 841 struct send_signal_irq_work *work = NULL; 842 843 /* Similar to bpf_probe_write_user, task needs to be 844 * in a sound condition and kernel memory access be 845 * permitted in order to send signal to the current 846 * task. 847 */ 848 if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) 849 return -EPERM; 850 if (unlikely(!nmi_uaccess_okay())) 851 return -EPERM; 852 /* Task should not be pid=1 to avoid kernel panic. */ 853 if (unlikely(is_global_init(current))) 854 return -EPERM; 855 856 if (preempt_count() != 0 || irqs_disabled()) { 857 /* Do an early check on signal validity. Otherwise, 858 * the error is lost in deferred irq_work. 859 */ 860 if (unlikely(!valid_signal(sig))) 861 return -EINVAL; 862 863 work = this_cpu_ptr(&send_signal_work); 864 if (irq_work_is_busy(&work->irq_work)) 865 return -EBUSY; 866 867 /* Add the current task, which is the target of sending signal, 868 * to the irq_work. The current task may change when queued 869 * irq works get executed. 870 */ 871 work->task = get_task_struct(current); 872 work->sig = sig; 873 work->type = type; 874 irq_work_queue(&work->irq_work); 875 return 0; 876 } 877 878 return group_send_sig_info(sig, SEND_SIG_PRIV, current, type); 879 } 880 881 BPF_CALL_1(bpf_send_signal, u32, sig) 882 { 883 return bpf_send_signal_common(sig, PIDTYPE_TGID); 884 } 885 886 static const struct bpf_func_proto bpf_send_signal_proto = { 887 .func = bpf_send_signal, 888 .gpl_only = false, 889 .ret_type = RET_INTEGER, 890 .arg1_type = ARG_ANYTHING, 891 }; 892 893 BPF_CALL_1(bpf_send_signal_thread, u32, sig) 894 { 895 return bpf_send_signal_common(sig, PIDTYPE_PID); 896 } 897 898 static const struct bpf_func_proto bpf_send_signal_thread_proto = { 899 .func = bpf_send_signal_thread, 900 .gpl_only = false, 901 .ret_type = RET_INTEGER, 902 .arg1_type = ARG_ANYTHING, 903 }; 904 905 BPF_CALL_3(bpf_d_path, struct path *, path, char *, buf, u32, sz) 906 { 907 struct path copy; 908 long len; 909 char *p; 910 911 if (!sz) 912 return 0; 913 914 /* 915 * The path pointer is verified as trusted and safe to use, 916 * but let's double check it's valid anyway to workaround 917 * potentially broken verifier. 918 */ 919 len = copy_from_kernel_nofault(©, path, sizeof(*path)); 920 if (len < 0) 921 return len; 922 923 p = d_path(©, buf, sz); 924 if (IS_ERR(p)) { 925 len = PTR_ERR(p); 926 } else { 927 len = buf + sz - p; 928 memmove(buf, p, len); 929 } 930 931 return len; 932 } 933 934 BTF_SET_START(btf_allowlist_d_path) 935 #ifdef CONFIG_SECURITY 936 BTF_ID(func, security_file_permission) 937 BTF_ID(func, security_inode_getattr) 938 BTF_ID(func, security_file_open) 939 #endif 940 #ifdef CONFIG_SECURITY_PATH 941 BTF_ID(func, security_path_truncate) 942 #endif 943 BTF_ID(func, vfs_truncate) 944 BTF_ID(func, vfs_fallocate) 945 BTF_ID(func, dentry_open) 946 BTF_ID(func, vfs_getattr) 947 BTF_ID(func, filp_close) 948 BTF_SET_END(btf_allowlist_d_path) 949 950 static bool bpf_d_path_allowed(const struct bpf_prog *prog) 951 { 952 if (prog->type == BPF_PROG_TYPE_TRACING && 953 prog->expected_attach_type == BPF_TRACE_ITER) 954 return true; 955 956 if (prog->type == BPF_PROG_TYPE_LSM) 957 return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id); 958 959 return btf_id_set_contains(&btf_allowlist_d_path, 960 prog->aux->attach_btf_id); 961 } 962 963 BTF_ID_LIST_SINGLE(bpf_d_path_btf_ids, struct, path) 964 965 static const struct bpf_func_proto bpf_d_path_proto = { 966 .func = bpf_d_path, 967 .gpl_only = false, 968 .ret_type = RET_INTEGER, 969 .arg1_type = ARG_PTR_TO_BTF_ID, 970 .arg1_btf_id = &bpf_d_path_btf_ids[0], 971 .arg2_type = ARG_PTR_TO_MEM, 972 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 973 .allowed = bpf_d_path_allowed, 974 }; 975 976 #define BTF_F_ALL (BTF_F_COMPACT | BTF_F_NONAME | \ 977 BTF_F_PTR_RAW | BTF_F_ZERO) 978 979 static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size, 980 u64 flags, const struct btf **btf, 981 s32 *btf_id) 982 { 983 const struct btf_type *t; 984 985 if (unlikely(flags & ~(BTF_F_ALL))) 986 return -EINVAL; 987 988 if (btf_ptr_size != sizeof(struct btf_ptr)) 989 return -EINVAL; 990 991 *btf = bpf_get_btf_vmlinux(); 992 993 if (IS_ERR_OR_NULL(*btf)) 994 return IS_ERR(*btf) ? PTR_ERR(*btf) : -EINVAL; 995 996 if (ptr->type_id > 0) 997 *btf_id = ptr->type_id; 998 else 999 return -EINVAL; 1000 1001 if (*btf_id > 0) 1002 t = btf_type_by_id(*btf, *btf_id); 1003 if (*btf_id <= 0 || !t) 1004 return -ENOENT; 1005 1006 return 0; 1007 } 1008 1009 BPF_CALL_5(bpf_snprintf_btf, char *, str, u32, str_size, struct btf_ptr *, ptr, 1010 u32, btf_ptr_size, u64, flags) 1011 { 1012 const struct btf *btf; 1013 s32 btf_id; 1014 int ret; 1015 1016 ret = bpf_btf_printf_prepare(ptr, btf_ptr_size, flags, &btf, &btf_id); 1017 if (ret) 1018 return ret; 1019 1020 return btf_type_snprintf_show(btf, btf_id, ptr->ptr, str, str_size, 1021 flags); 1022 } 1023 1024 const struct bpf_func_proto bpf_snprintf_btf_proto = { 1025 .func = bpf_snprintf_btf, 1026 .gpl_only = false, 1027 .ret_type = RET_INTEGER, 1028 .arg1_type = ARG_PTR_TO_MEM, 1029 .arg2_type = ARG_CONST_SIZE, 1030 .arg3_type = ARG_PTR_TO_MEM | MEM_RDONLY, 1031 .arg4_type = ARG_CONST_SIZE, 1032 .arg5_type = ARG_ANYTHING, 1033 }; 1034 1035 BPF_CALL_1(bpf_get_func_ip_tracing, void *, ctx) 1036 { 1037 /* This helper call is inlined by verifier. */ 1038 return ((u64 *)ctx)[-2]; 1039 } 1040 1041 static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = { 1042 .func = bpf_get_func_ip_tracing, 1043 .gpl_only = true, 1044 .ret_type = RET_INTEGER, 1045 .arg1_type = ARG_PTR_TO_CTX, 1046 }; 1047 1048 #ifdef CONFIG_X86_KERNEL_IBT 1049 static unsigned long get_entry_ip(unsigned long fentry_ip) 1050 { 1051 u32 instr; 1052 1053 /* Being extra safe in here in case entry ip is on the page-edge. */ 1054 if (get_kernel_nofault(instr, (u32 *) fentry_ip - 1)) 1055 return fentry_ip; 1056 if (is_endbr(instr)) 1057 fentry_ip -= ENDBR_INSN_SIZE; 1058 return fentry_ip; 1059 } 1060 #else 1061 #define get_entry_ip(fentry_ip) fentry_ip 1062 #endif 1063 1064 BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs) 1065 { 1066 struct bpf_trace_run_ctx *run_ctx __maybe_unused; 1067 struct kprobe *kp; 1068 1069 #ifdef CONFIG_UPROBES 1070 run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); 1071 if (run_ctx->is_uprobe) 1072 return ((struct uprobe_dispatch_data *)current->utask->vaddr)->bp_addr; 1073 #endif 1074 1075 kp = kprobe_running(); 1076 1077 if (!kp || !(kp->flags & KPROBE_FLAG_ON_FUNC_ENTRY)) 1078 return 0; 1079 1080 return get_entry_ip((uintptr_t)kp->addr); 1081 } 1082 1083 static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = { 1084 .func = bpf_get_func_ip_kprobe, 1085 .gpl_only = true, 1086 .ret_type = RET_INTEGER, 1087 .arg1_type = ARG_PTR_TO_CTX, 1088 }; 1089 1090 BPF_CALL_1(bpf_get_func_ip_kprobe_multi, struct pt_regs *, regs) 1091 { 1092 return bpf_kprobe_multi_entry_ip(current->bpf_ctx); 1093 } 1094 1095 static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe_multi = { 1096 .func = bpf_get_func_ip_kprobe_multi, 1097 .gpl_only = false, 1098 .ret_type = RET_INTEGER, 1099 .arg1_type = ARG_PTR_TO_CTX, 1100 }; 1101 1102 BPF_CALL_1(bpf_get_attach_cookie_kprobe_multi, struct pt_regs *, regs) 1103 { 1104 return bpf_kprobe_multi_cookie(current->bpf_ctx); 1105 } 1106 1107 static const struct bpf_func_proto bpf_get_attach_cookie_proto_kmulti = { 1108 .func = bpf_get_attach_cookie_kprobe_multi, 1109 .gpl_only = false, 1110 .ret_type = RET_INTEGER, 1111 .arg1_type = ARG_PTR_TO_CTX, 1112 }; 1113 1114 BPF_CALL_1(bpf_get_func_ip_uprobe_multi, struct pt_regs *, regs) 1115 { 1116 return bpf_uprobe_multi_entry_ip(current->bpf_ctx); 1117 } 1118 1119 static const struct bpf_func_proto bpf_get_func_ip_proto_uprobe_multi = { 1120 .func = bpf_get_func_ip_uprobe_multi, 1121 .gpl_only = false, 1122 .ret_type = RET_INTEGER, 1123 .arg1_type = ARG_PTR_TO_CTX, 1124 }; 1125 1126 BPF_CALL_1(bpf_get_attach_cookie_uprobe_multi, struct pt_regs *, regs) 1127 { 1128 return bpf_uprobe_multi_cookie(current->bpf_ctx); 1129 } 1130 1131 static const struct bpf_func_proto bpf_get_attach_cookie_proto_umulti = { 1132 .func = bpf_get_attach_cookie_uprobe_multi, 1133 .gpl_only = false, 1134 .ret_type = RET_INTEGER, 1135 .arg1_type = ARG_PTR_TO_CTX, 1136 }; 1137 1138 BPF_CALL_1(bpf_get_attach_cookie_trace, void *, ctx) 1139 { 1140 struct bpf_trace_run_ctx *run_ctx; 1141 1142 run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); 1143 return run_ctx->bpf_cookie; 1144 } 1145 1146 static const struct bpf_func_proto bpf_get_attach_cookie_proto_trace = { 1147 .func = bpf_get_attach_cookie_trace, 1148 .gpl_only = false, 1149 .ret_type = RET_INTEGER, 1150 .arg1_type = ARG_PTR_TO_CTX, 1151 }; 1152 1153 BPF_CALL_1(bpf_get_attach_cookie_pe, struct bpf_perf_event_data_kern *, ctx) 1154 { 1155 return ctx->event->bpf_cookie; 1156 } 1157 1158 static const struct bpf_func_proto bpf_get_attach_cookie_proto_pe = { 1159 .func = bpf_get_attach_cookie_pe, 1160 .gpl_only = false, 1161 .ret_type = RET_INTEGER, 1162 .arg1_type = ARG_PTR_TO_CTX, 1163 }; 1164 1165 BPF_CALL_1(bpf_get_attach_cookie_tracing, void *, ctx) 1166 { 1167 struct bpf_trace_run_ctx *run_ctx; 1168 1169 run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); 1170 return run_ctx->bpf_cookie; 1171 } 1172 1173 static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = { 1174 .func = bpf_get_attach_cookie_tracing, 1175 .gpl_only = false, 1176 .ret_type = RET_INTEGER, 1177 .arg1_type = ARG_PTR_TO_CTX, 1178 }; 1179 1180 BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags) 1181 { 1182 #ifndef CONFIG_X86 1183 return -ENOENT; 1184 #else 1185 static const u32 br_entry_size = sizeof(struct perf_branch_entry); 1186 u32 entry_cnt = size / br_entry_size; 1187 1188 entry_cnt = static_call(perf_snapshot_branch_stack)(buf, entry_cnt); 1189 1190 if (unlikely(flags)) 1191 return -EINVAL; 1192 1193 if (!entry_cnt) 1194 return -ENOENT; 1195 1196 return entry_cnt * br_entry_size; 1197 #endif 1198 } 1199 1200 static const struct bpf_func_proto bpf_get_branch_snapshot_proto = { 1201 .func = bpf_get_branch_snapshot, 1202 .gpl_only = true, 1203 .ret_type = RET_INTEGER, 1204 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 1205 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 1206 }; 1207 1208 BPF_CALL_3(get_func_arg, void *, ctx, u32, n, u64 *, value) 1209 { 1210 /* This helper call is inlined by verifier. */ 1211 u64 nr_args = ((u64 *)ctx)[-1]; 1212 1213 if ((u64) n >= nr_args) 1214 return -EINVAL; 1215 *value = ((u64 *)ctx)[n]; 1216 return 0; 1217 } 1218 1219 static const struct bpf_func_proto bpf_get_func_arg_proto = { 1220 .func = get_func_arg, 1221 .ret_type = RET_INTEGER, 1222 .arg1_type = ARG_PTR_TO_CTX, 1223 .arg2_type = ARG_ANYTHING, 1224 .arg3_type = ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED, 1225 .arg3_size = sizeof(u64), 1226 }; 1227 1228 BPF_CALL_2(get_func_ret, void *, ctx, u64 *, value) 1229 { 1230 /* This helper call is inlined by verifier. */ 1231 u64 nr_args = ((u64 *)ctx)[-1]; 1232 1233 *value = ((u64 *)ctx)[nr_args]; 1234 return 0; 1235 } 1236 1237 static const struct bpf_func_proto bpf_get_func_ret_proto = { 1238 .func = get_func_ret, 1239 .ret_type = RET_INTEGER, 1240 .arg1_type = ARG_PTR_TO_CTX, 1241 .arg2_type = ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED, 1242 .arg2_size = sizeof(u64), 1243 }; 1244 1245 BPF_CALL_1(get_func_arg_cnt, void *, ctx) 1246 { 1247 /* This helper call is inlined by verifier. */ 1248 return ((u64 *)ctx)[-1]; 1249 } 1250 1251 static const struct bpf_func_proto bpf_get_func_arg_cnt_proto = { 1252 .func = get_func_arg_cnt, 1253 .ret_type = RET_INTEGER, 1254 .arg1_type = ARG_PTR_TO_CTX, 1255 }; 1256 1257 #ifdef CONFIG_KEYS 1258 __diag_push(); 1259 __diag_ignore_all("-Wmissing-prototypes", 1260 "kfuncs which will be used in BPF programs"); 1261 1262 /** 1263 * bpf_lookup_user_key - lookup a key by its serial 1264 * @serial: key handle serial number 1265 * @flags: lookup-specific flags 1266 * 1267 * Search a key with a given *serial* and the provided *flags*. 1268 * If found, increment the reference count of the key by one, and 1269 * return it in the bpf_key structure. 1270 * 1271 * The bpf_key structure must be passed to bpf_key_put() when done 1272 * with it, so that the key reference count is decremented and the 1273 * bpf_key structure is freed. 1274 * 1275 * Permission checks are deferred to the time the key is used by 1276 * one of the available key-specific kfuncs. 1277 * 1278 * Set *flags* with KEY_LOOKUP_CREATE, to attempt creating a requested 1279 * special keyring (e.g. session keyring), if it doesn't yet exist. 1280 * Set *flags* with KEY_LOOKUP_PARTIAL, to lookup a key without waiting 1281 * for the key construction, and to retrieve uninstantiated keys (keys 1282 * without data attached to them). 1283 * 1284 * Return: a bpf_key pointer with a valid key pointer if the key is found, a 1285 * NULL pointer otherwise. 1286 */ 1287 __bpf_kfunc struct bpf_key *bpf_lookup_user_key(u32 serial, u64 flags) 1288 { 1289 key_ref_t key_ref; 1290 struct bpf_key *bkey; 1291 1292 if (flags & ~KEY_LOOKUP_ALL) 1293 return NULL; 1294 1295 /* 1296 * Permission check is deferred until the key is used, as the 1297 * intent of the caller is unknown here. 1298 */ 1299 key_ref = lookup_user_key(serial, flags, KEY_DEFER_PERM_CHECK); 1300 if (IS_ERR(key_ref)) 1301 return NULL; 1302 1303 bkey = kmalloc(sizeof(*bkey), GFP_KERNEL); 1304 if (!bkey) { 1305 key_put(key_ref_to_ptr(key_ref)); 1306 return NULL; 1307 } 1308 1309 bkey->key = key_ref_to_ptr(key_ref); 1310 bkey->has_ref = true; 1311 1312 return bkey; 1313 } 1314 1315 /** 1316 * bpf_lookup_system_key - lookup a key by a system-defined ID 1317 * @id: key ID 1318 * 1319 * Obtain a bpf_key structure with a key pointer set to the passed key ID. 1320 * The key pointer is marked as invalid, to prevent bpf_key_put() from 1321 * attempting to decrement the key reference count on that pointer. The key 1322 * pointer set in such way is currently understood only by 1323 * verify_pkcs7_signature(). 1324 * 1325 * Set *id* to one of the values defined in include/linux/verification.h: 1326 * 0 for the primary keyring (immutable keyring of system keys); 1327 * VERIFY_USE_SECONDARY_KEYRING for both the primary and secondary keyring 1328 * (where keys can be added only if they are vouched for by existing keys 1329 * in those keyrings); VERIFY_USE_PLATFORM_KEYRING for the platform 1330 * keyring (primarily used by the integrity subsystem to verify a kexec'ed 1331 * kerned image and, possibly, the initramfs signature). 1332 * 1333 * Return: a bpf_key pointer with an invalid key pointer set from the 1334 * pre-determined ID on success, a NULL pointer otherwise 1335 */ 1336 __bpf_kfunc struct bpf_key *bpf_lookup_system_key(u64 id) 1337 { 1338 struct bpf_key *bkey; 1339 1340 if (system_keyring_id_check(id) < 0) 1341 return NULL; 1342 1343 bkey = kmalloc(sizeof(*bkey), GFP_ATOMIC); 1344 if (!bkey) 1345 return NULL; 1346 1347 bkey->key = (struct key *)(unsigned long)id; 1348 bkey->has_ref = false; 1349 1350 return bkey; 1351 } 1352 1353 /** 1354 * bpf_key_put - decrement key reference count if key is valid and free bpf_key 1355 * @bkey: bpf_key structure 1356 * 1357 * Decrement the reference count of the key inside *bkey*, if the pointer 1358 * is valid, and free *bkey*. 1359 */ 1360 __bpf_kfunc void bpf_key_put(struct bpf_key *bkey) 1361 { 1362 if (bkey->has_ref) 1363 key_put(bkey->key); 1364 1365 kfree(bkey); 1366 } 1367 1368 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION 1369 /** 1370 * bpf_verify_pkcs7_signature - verify a PKCS#7 signature 1371 * @data_ptr: data to verify 1372 * @sig_ptr: signature of the data 1373 * @trusted_keyring: keyring with keys trusted for signature verification 1374 * 1375 * Verify the PKCS#7 signature *sig_ptr* against the supplied *data_ptr* 1376 * with keys in a keyring referenced by *trusted_keyring*. 1377 * 1378 * Return: 0 on success, a negative value on error. 1379 */ 1380 __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr, 1381 struct bpf_dynptr_kern *sig_ptr, 1382 struct bpf_key *trusted_keyring) 1383 { 1384 int ret; 1385 1386 if (trusted_keyring->has_ref) { 1387 /* 1388 * Do the permission check deferred in bpf_lookup_user_key(). 1389 * See bpf_lookup_user_key() for more details. 1390 * 1391 * A call to key_task_permission() here would be redundant, as 1392 * it is already done by keyring_search() called by 1393 * find_asymmetric_key(). 1394 */ 1395 ret = key_validate(trusted_keyring->key); 1396 if (ret < 0) 1397 return ret; 1398 } 1399 1400 return verify_pkcs7_signature(data_ptr->data, 1401 __bpf_dynptr_size(data_ptr), 1402 sig_ptr->data, 1403 __bpf_dynptr_size(sig_ptr), 1404 trusted_keyring->key, 1405 VERIFYING_UNSPECIFIED_SIGNATURE, NULL, 1406 NULL); 1407 } 1408 #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ 1409 1410 __diag_pop(); 1411 1412 BTF_SET8_START(key_sig_kfunc_set) 1413 BTF_ID_FLAGS(func, bpf_lookup_user_key, KF_ACQUIRE | KF_RET_NULL | KF_SLEEPABLE) 1414 BTF_ID_FLAGS(func, bpf_lookup_system_key, KF_ACQUIRE | KF_RET_NULL) 1415 BTF_ID_FLAGS(func, bpf_key_put, KF_RELEASE) 1416 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION 1417 BTF_ID_FLAGS(func, bpf_verify_pkcs7_signature, KF_SLEEPABLE) 1418 #endif 1419 BTF_SET8_END(key_sig_kfunc_set) 1420 1421 static const struct btf_kfunc_id_set bpf_key_sig_kfunc_set = { 1422 .owner = THIS_MODULE, 1423 .set = &key_sig_kfunc_set, 1424 }; 1425 1426 static int __init bpf_key_sig_kfuncs_init(void) 1427 { 1428 return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, 1429 &bpf_key_sig_kfunc_set); 1430 } 1431 1432 late_initcall(bpf_key_sig_kfuncs_init); 1433 #endif /* CONFIG_KEYS */ 1434 1435 static const struct bpf_func_proto * 1436 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1437 { 1438 switch (func_id) { 1439 case BPF_FUNC_map_lookup_elem: 1440 return &bpf_map_lookup_elem_proto; 1441 case BPF_FUNC_map_update_elem: 1442 return &bpf_map_update_elem_proto; 1443 case BPF_FUNC_map_delete_elem: 1444 return &bpf_map_delete_elem_proto; 1445 case BPF_FUNC_map_push_elem: 1446 return &bpf_map_push_elem_proto; 1447 case BPF_FUNC_map_pop_elem: 1448 return &bpf_map_pop_elem_proto; 1449 case BPF_FUNC_map_peek_elem: 1450 return &bpf_map_peek_elem_proto; 1451 case BPF_FUNC_map_lookup_percpu_elem: 1452 return &bpf_map_lookup_percpu_elem_proto; 1453 case BPF_FUNC_ktime_get_ns: 1454 return &bpf_ktime_get_ns_proto; 1455 case BPF_FUNC_ktime_get_boot_ns: 1456 return &bpf_ktime_get_boot_ns_proto; 1457 case BPF_FUNC_tail_call: 1458 return &bpf_tail_call_proto; 1459 case BPF_FUNC_get_current_pid_tgid: 1460 return &bpf_get_current_pid_tgid_proto; 1461 case BPF_FUNC_get_current_task: 1462 return &bpf_get_current_task_proto; 1463 case BPF_FUNC_get_current_task_btf: 1464 return &bpf_get_current_task_btf_proto; 1465 case BPF_FUNC_task_pt_regs: 1466 return &bpf_task_pt_regs_proto; 1467 case BPF_FUNC_get_current_uid_gid: 1468 return &bpf_get_current_uid_gid_proto; 1469 case BPF_FUNC_get_current_comm: 1470 return &bpf_get_current_comm_proto; 1471 case BPF_FUNC_trace_printk: 1472 return bpf_get_trace_printk_proto(); 1473 case BPF_FUNC_get_smp_processor_id: 1474 return &bpf_get_smp_processor_id_proto; 1475 case BPF_FUNC_get_numa_node_id: 1476 return &bpf_get_numa_node_id_proto; 1477 case BPF_FUNC_perf_event_read: 1478 return &bpf_perf_event_read_proto; 1479 case BPF_FUNC_current_task_under_cgroup: 1480 return &bpf_current_task_under_cgroup_proto; 1481 case BPF_FUNC_get_prandom_u32: 1482 return &bpf_get_prandom_u32_proto; 1483 case BPF_FUNC_probe_write_user: 1484 return security_locked_down(LOCKDOWN_BPF_WRITE_USER) < 0 ? 1485 NULL : bpf_get_probe_write_proto(); 1486 case BPF_FUNC_probe_read_user: 1487 return &bpf_probe_read_user_proto; 1488 case BPF_FUNC_probe_read_kernel: 1489 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ? 1490 NULL : &bpf_probe_read_kernel_proto; 1491 case BPF_FUNC_probe_read_user_str: 1492 return &bpf_probe_read_user_str_proto; 1493 case BPF_FUNC_probe_read_kernel_str: 1494 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ? 1495 NULL : &bpf_probe_read_kernel_str_proto; 1496 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 1497 case BPF_FUNC_probe_read: 1498 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ? 1499 NULL : &bpf_probe_read_compat_proto; 1500 case BPF_FUNC_probe_read_str: 1501 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ? 1502 NULL : &bpf_probe_read_compat_str_proto; 1503 #endif 1504 #ifdef CONFIG_CGROUPS 1505 case BPF_FUNC_cgrp_storage_get: 1506 return &bpf_cgrp_storage_get_proto; 1507 case BPF_FUNC_cgrp_storage_delete: 1508 return &bpf_cgrp_storage_delete_proto; 1509 #endif 1510 case BPF_FUNC_send_signal: 1511 return &bpf_send_signal_proto; 1512 case BPF_FUNC_send_signal_thread: 1513 return &bpf_send_signal_thread_proto; 1514 case BPF_FUNC_perf_event_read_value: 1515 return &bpf_perf_event_read_value_proto; 1516 case BPF_FUNC_get_ns_current_pid_tgid: 1517 return &bpf_get_ns_current_pid_tgid_proto; 1518 case BPF_FUNC_ringbuf_output: 1519 return &bpf_ringbuf_output_proto; 1520 case BPF_FUNC_ringbuf_reserve: 1521 return &bpf_ringbuf_reserve_proto; 1522 case BPF_FUNC_ringbuf_submit: 1523 return &bpf_ringbuf_submit_proto; 1524 case BPF_FUNC_ringbuf_discard: 1525 return &bpf_ringbuf_discard_proto; 1526 case BPF_FUNC_ringbuf_query: 1527 return &bpf_ringbuf_query_proto; 1528 case BPF_FUNC_jiffies64: 1529 return &bpf_jiffies64_proto; 1530 case BPF_FUNC_get_task_stack: 1531 return &bpf_get_task_stack_proto; 1532 case BPF_FUNC_copy_from_user: 1533 return &bpf_copy_from_user_proto; 1534 case BPF_FUNC_copy_from_user_task: 1535 return &bpf_copy_from_user_task_proto; 1536 case BPF_FUNC_snprintf_btf: 1537 return &bpf_snprintf_btf_proto; 1538 case BPF_FUNC_per_cpu_ptr: 1539 return &bpf_per_cpu_ptr_proto; 1540 case BPF_FUNC_this_cpu_ptr: 1541 return &bpf_this_cpu_ptr_proto; 1542 case BPF_FUNC_task_storage_get: 1543 if (bpf_prog_check_recur(prog)) 1544 return &bpf_task_storage_get_recur_proto; 1545 return &bpf_task_storage_get_proto; 1546 case BPF_FUNC_task_storage_delete: 1547 if (bpf_prog_check_recur(prog)) 1548 return &bpf_task_storage_delete_recur_proto; 1549 return &bpf_task_storage_delete_proto; 1550 case BPF_FUNC_for_each_map_elem: 1551 return &bpf_for_each_map_elem_proto; 1552 case BPF_FUNC_snprintf: 1553 return &bpf_snprintf_proto; 1554 case BPF_FUNC_get_func_ip: 1555 return &bpf_get_func_ip_proto_tracing; 1556 case BPF_FUNC_get_branch_snapshot: 1557 return &bpf_get_branch_snapshot_proto; 1558 case BPF_FUNC_find_vma: 1559 return &bpf_find_vma_proto; 1560 case BPF_FUNC_trace_vprintk: 1561 return bpf_get_trace_vprintk_proto(); 1562 default: 1563 return bpf_base_func_proto(func_id); 1564 } 1565 } 1566 1567 static const struct bpf_func_proto * 1568 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1569 { 1570 switch (func_id) { 1571 case BPF_FUNC_perf_event_output: 1572 return &bpf_perf_event_output_proto; 1573 case BPF_FUNC_get_stackid: 1574 return &bpf_get_stackid_proto; 1575 case BPF_FUNC_get_stack: 1576 return &bpf_get_stack_proto; 1577 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 1578 case BPF_FUNC_override_return: 1579 return &bpf_override_return_proto; 1580 #endif 1581 case BPF_FUNC_get_func_ip: 1582 if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI) 1583 return &bpf_get_func_ip_proto_kprobe_multi; 1584 if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI) 1585 return &bpf_get_func_ip_proto_uprobe_multi; 1586 return &bpf_get_func_ip_proto_kprobe; 1587 case BPF_FUNC_get_attach_cookie: 1588 if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI) 1589 return &bpf_get_attach_cookie_proto_kmulti; 1590 if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI) 1591 return &bpf_get_attach_cookie_proto_umulti; 1592 return &bpf_get_attach_cookie_proto_trace; 1593 default: 1594 return bpf_tracing_func_proto(func_id, prog); 1595 } 1596 } 1597 1598 /* bpf+kprobe programs can access fields of 'struct pt_regs' */ 1599 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1600 const struct bpf_prog *prog, 1601 struct bpf_insn_access_aux *info) 1602 { 1603 if (off < 0 || off >= sizeof(struct pt_regs)) 1604 return false; 1605 if (type != BPF_READ) 1606 return false; 1607 if (off % size != 0) 1608 return false; 1609 /* 1610 * Assertion for 32 bit to make sure last 8 byte access 1611 * (BPF_DW) to the last 4 byte member is disallowed. 1612 */ 1613 if (off + size > sizeof(struct pt_regs)) 1614 return false; 1615 1616 return true; 1617 } 1618 1619 const struct bpf_verifier_ops kprobe_verifier_ops = { 1620 .get_func_proto = kprobe_prog_func_proto, 1621 .is_valid_access = kprobe_prog_is_valid_access, 1622 }; 1623 1624 const struct bpf_prog_ops kprobe_prog_ops = { 1625 }; 1626 1627 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, 1628 u64, flags, void *, data, u64, size) 1629 { 1630 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 1631 1632 /* 1633 * r1 points to perf tracepoint buffer where first 8 bytes are hidden 1634 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it 1635 * from there and call the same bpf_perf_event_output() helper inline. 1636 */ 1637 return ____bpf_perf_event_output(regs, map, flags, data, size); 1638 } 1639 1640 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { 1641 .func = bpf_perf_event_output_tp, 1642 .gpl_only = true, 1643 .ret_type = RET_INTEGER, 1644 .arg1_type = ARG_PTR_TO_CTX, 1645 .arg2_type = ARG_CONST_MAP_PTR, 1646 .arg3_type = ARG_ANYTHING, 1647 .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY, 1648 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 1649 }; 1650 1651 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, 1652 u64, flags) 1653 { 1654 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 1655 1656 /* 1657 * Same comment as in bpf_perf_event_output_tp(), only that this time 1658 * the other helper's function body cannot be inlined due to being 1659 * external, thus we need to call raw helper function. 1660 */ 1661 return bpf_get_stackid((unsigned long) regs, (unsigned long) map, 1662 flags, 0, 0); 1663 } 1664 1665 static const struct bpf_func_proto bpf_get_stackid_proto_tp = { 1666 .func = bpf_get_stackid_tp, 1667 .gpl_only = true, 1668 .ret_type = RET_INTEGER, 1669 .arg1_type = ARG_PTR_TO_CTX, 1670 .arg2_type = ARG_CONST_MAP_PTR, 1671 .arg3_type = ARG_ANYTHING, 1672 }; 1673 1674 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size, 1675 u64, flags) 1676 { 1677 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 1678 1679 return bpf_get_stack((unsigned long) regs, (unsigned long) buf, 1680 (unsigned long) size, flags, 0); 1681 } 1682 1683 static const struct bpf_func_proto bpf_get_stack_proto_tp = { 1684 .func = bpf_get_stack_tp, 1685 .gpl_only = true, 1686 .ret_type = RET_INTEGER, 1687 .arg1_type = ARG_PTR_TO_CTX, 1688 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 1689 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1690 .arg4_type = ARG_ANYTHING, 1691 }; 1692 1693 static const struct bpf_func_proto * 1694 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1695 { 1696 switch (func_id) { 1697 case BPF_FUNC_perf_event_output: 1698 return &bpf_perf_event_output_proto_tp; 1699 case BPF_FUNC_get_stackid: 1700 return &bpf_get_stackid_proto_tp; 1701 case BPF_FUNC_get_stack: 1702 return &bpf_get_stack_proto_tp; 1703 case BPF_FUNC_get_attach_cookie: 1704 return &bpf_get_attach_cookie_proto_trace; 1705 default: 1706 return bpf_tracing_func_proto(func_id, prog); 1707 } 1708 } 1709 1710 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1711 const struct bpf_prog *prog, 1712 struct bpf_insn_access_aux *info) 1713 { 1714 if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) 1715 return false; 1716 if (type != BPF_READ) 1717 return false; 1718 if (off % size != 0) 1719 return false; 1720 1721 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); 1722 return true; 1723 } 1724 1725 const struct bpf_verifier_ops tracepoint_verifier_ops = { 1726 .get_func_proto = tp_prog_func_proto, 1727 .is_valid_access = tp_prog_is_valid_access, 1728 }; 1729 1730 const struct bpf_prog_ops tracepoint_prog_ops = { 1731 }; 1732 1733 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx, 1734 struct bpf_perf_event_value *, buf, u32, size) 1735 { 1736 int err = -EINVAL; 1737 1738 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 1739 goto clear; 1740 err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, 1741 &buf->running); 1742 if (unlikely(err)) 1743 goto clear; 1744 return 0; 1745 clear: 1746 memset(buf, 0, size); 1747 return err; 1748 } 1749 1750 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { 1751 .func = bpf_perf_prog_read_value, 1752 .gpl_only = true, 1753 .ret_type = RET_INTEGER, 1754 .arg1_type = ARG_PTR_TO_CTX, 1755 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 1756 .arg3_type = ARG_CONST_SIZE, 1757 }; 1758 1759 BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx, 1760 void *, buf, u32, size, u64, flags) 1761 { 1762 static const u32 br_entry_size = sizeof(struct perf_branch_entry); 1763 struct perf_branch_stack *br_stack = ctx->data->br_stack; 1764 u32 to_copy; 1765 1766 if (unlikely(flags & ~BPF_F_GET_BRANCH_RECORDS_SIZE)) 1767 return -EINVAL; 1768 1769 if (unlikely(!(ctx->data->sample_flags & PERF_SAMPLE_BRANCH_STACK))) 1770 return -ENOENT; 1771 1772 if (unlikely(!br_stack)) 1773 return -ENOENT; 1774 1775 if (flags & BPF_F_GET_BRANCH_RECORDS_SIZE) 1776 return br_stack->nr * br_entry_size; 1777 1778 if (!buf || (size % br_entry_size != 0)) 1779 return -EINVAL; 1780 1781 to_copy = min_t(u32, br_stack->nr * br_entry_size, size); 1782 memcpy(buf, br_stack->entries, to_copy); 1783 1784 return to_copy; 1785 } 1786 1787 static const struct bpf_func_proto bpf_read_branch_records_proto = { 1788 .func = bpf_read_branch_records, 1789 .gpl_only = true, 1790 .ret_type = RET_INTEGER, 1791 .arg1_type = ARG_PTR_TO_CTX, 1792 .arg2_type = ARG_PTR_TO_MEM_OR_NULL, 1793 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1794 .arg4_type = ARG_ANYTHING, 1795 }; 1796 1797 static const struct bpf_func_proto * 1798 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1799 { 1800 switch (func_id) { 1801 case BPF_FUNC_perf_event_output: 1802 return &bpf_perf_event_output_proto_tp; 1803 case BPF_FUNC_get_stackid: 1804 return &bpf_get_stackid_proto_pe; 1805 case BPF_FUNC_get_stack: 1806 return &bpf_get_stack_proto_pe; 1807 case BPF_FUNC_perf_prog_read_value: 1808 return &bpf_perf_prog_read_value_proto; 1809 case BPF_FUNC_read_branch_records: 1810 return &bpf_read_branch_records_proto; 1811 case BPF_FUNC_get_attach_cookie: 1812 return &bpf_get_attach_cookie_proto_pe; 1813 default: 1814 return bpf_tracing_func_proto(func_id, prog); 1815 } 1816 } 1817 1818 /* 1819 * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp 1820 * to avoid potential recursive reuse issue when/if tracepoints are added 1821 * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. 1822 * 1823 * Since raw tracepoints run despite bpf_prog_active, support concurrent usage 1824 * in normal, irq, and nmi context. 1825 */ 1826 struct bpf_raw_tp_regs { 1827 struct pt_regs regs[3]; 1828 }; 1829 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); 1830 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); 1831 static struct pt_regs *get_bpf_raw_tp_regs(void) 1832 { 1833 struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); 1834 int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); 1835 1836 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { 1837 this_cpu_dec(bpf_raw_tp_nest_level); 1838 return ERR_PTR(-EBUSY); 1839 } 1840 1841 return &tp_regs->regs[nest_level - 1]; 1842 } 1843 1844 static void put_bpf_raw_tp_regs(void) 1845 { 1846 this_cpu_dec(bpf_raw_tp_nest_level); 1847 } 1848 1849 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, 1850 struct bpf_map *, map, u64, flags, void *, data, u64, size) 1851 { 1852 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1853 int ret; 1854 1855 if (IS_ERR(regs)) 1856 return PTR_ERR(regs); 1857 1858 perf_fetch_caller_regs(regs); 1859 ret = ____bpf_perf_event_output(regs, map, flags, data, size); 1860 1861 put_bpf_raw_tp_regs(); 1862 return ret; 1863 } 1864 1865 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { 1866 .func = bpf_perf_event_output_raw_tp, 1867 .gpl_only = true, 1868 .ret_type = RET_INTEGER, 1869 .arg1_type = ARG_PTR_TO_CTX, 1870 .arg2_type = ARG_CONST_MAP_PTR, 1871 .arg3_type = ARG_ANYTHING, 1872 .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY, 1873 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 1874 }; 1875 1876 extern const struct bpf_func_proto bpf_skb_output_proto; 1877 extern const struct bpf_func_proto bpf_xdp_output_proto; 1878 extern const struct bpf_func_proto bpf_xdp_get_buff_len_trace_proto; 1879 1880 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, 1881 struct bpf_map *, map, u64, flags) 1882 { 1883 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1884 int ret; 1885 1886 if (IS_ERR(regs)) 1887 return PTR_ERR(regs); 1888 1889 perf_fetch_caller_regs(regs); 1890 /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ 1891 ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, 1892 flags, 0, 0); 1893 put_bpf_raw_tp_regs(); 1894 return ret; 1895 } 1896 1897 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { 1898 .func = bpf_get_stackid_raw_tp, 1899 .gpl_only = true, 1900 .ret_type = RET_INTEGER, 1901 .arg1_type = ARG_PTR_TO_CTX, 1902 .arg2_type = ARG_CONST_MAP_PTR, 1903 .arg3_type = ARG_ANYTHING, 1904 }; 1905 1906 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, 1907 void *, buf, u32, size, u64, flags) 1908 { 1909 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1910 int ret; 1911 1912 if (IS_ERR(regs)) 1913 return PTR_ERR(regs); 1914 1915 perf_fetch_caller_regs(regs); 1916 ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, 1917 (unsigned long) size, flags, 0); 1918 put_bpf_raw_tp_regs(); 1919 return ret; 1920 } 1921 1922 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { 1923 .func = bpf_get_stack_raw_tp, 1924 .gpl_only = true, 1925 .ret_type = RET_INTEGER, 1926 .arg1_type = ARG_PTR_TO_CTX, 1927 .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 1928 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1929 .arg4_type = ARG_ANYTHING, 1930 }; 1931 1932 static const struct bpf_func_proto * 1933 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1934 { 1935 switch (func_id) { 1936 case BPF_FUNC_perf_event_output: 1937 return &bpf_perf_event_output_proto_raw_tp; 1938 case BPF_FUNC_get_stackid: 1939 return &bpf_get_stackid_proto_raw_tp; 1940 case BPF_FUNC_get_stack: 1941 return &bpf_get_stack_proto_raw_tp; 1942 default: 1943 return bpf_tracing_func_proto(func_id, prog); 1944 } 1945 } 1946 1947 const struct bpf_func_proto * 1948 tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1949 { 1950 const struct bpf_func_proto *fn; 1951 1952 switch (func_id) { 1953 #ifdef CONFIG_NET 1954 case BPF_FUNC_skb_output: 1955 return &bpf_skb_output_proto; 1956 case BPF_FUNC_xdp_output: 1957 return &bpf_xdp_output_proto; 1958 case BPF_FUNC_skc_to_tcp6_sock: 1959 return &bpf_skc_to_tcp6_sock_proto; 1960 case BPF_FUNC_skc_to_tcp_sock: 1961 return &bpf_skc_to_tcp_sock_proto; 1962 case BPF_FUNC_skc_to_tcp_timewait_sock: 1963 return &bpf_skc_to_tcp_timewait_sock_proto; 1964 case BPF_FUNC_skc_to_tcp_request_sock: 1965 return &bpf_skc_to_tcp_request_sock_proto; 1966 case BPF_FUNC_skc_to_udp6_sock: 1967 return &bpf_skc_to_udp6_sock_proto; 1968 case BPF_FUNC_skc_to_unix_sock: 1969 return &bpf_skc_to_unix_sock_proto; 1970 case BPF_FUNC_skc_to_mptcp_sock: 1971 return &bpf_skc_to_mptcp_sock_proto; 1972 case BPF_FUNC_sk_storage_get: 1973 return &bpf_sk_storage_get_tracing_proto; 1974 case BPF_FUNC_sk_storage_delete: 1975 return &bpf_sk_storage_delete_tracing_proto; 1976 case BPF_FUNC_sock_from_file: 1977 return &bpf_sock_from_file_proto; 1978 case BPF_FUNC_get_socket_cookie: 1979 return &bpf_get_socket_ptr_cookie_proto; 1980 case BPF_FUNC_xdp_get_buff_len: 1981 return &bpf_xdp_get_buff_len_trace_proto; 1982 #endif 1983 case BPF_FUNC_seq_printf: 1984 return prog->expected_attach_type == BPF_TRACE_ITER ? 1985 &bpf_seq_printf_proto : 1986 NULL; 1987 case BPF_FUNC_seq_write: 1988 return prog->expected_attach_type == BPF_TRACE_ITER ? 1989 &bpf_seq_write_proto : 1990 NULL; 1991 case BPF_FUNC_seq_printf_btf: 1992 return prog->expected_attach_type == BPF_TRACE_ITER ? 1993 &bpf_seq_printf_btf_proto : 1994 NULL; 1995 case BPF_FUNC_d_path: 1996 return &bpf_d_path_proto; 1997 case BPF_FUNC_get_func_arg: 1998 return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_proto : NULL; 1999 case BPF_FUNC_get_func_ret: 2000 return bpf_prog_has_trampoline(prog) ? &bpf_get_func_ret_proto : NULL; 2001 case BPF_FUNC_get_func_arg_cnt: 2002 return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_cnt_proto : NULL; 2003 case BPF_FUNC_get_attach_cookie: 2004 return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto_tracing : NULL; 2005 default: 2006 fn = raw_tp_prog_func_proto(func_id, prog); 2007 if (!fn && prog->expected_attach_type == BPF_TRACE_ITER) 2008 fn = bpf_iter_get_func_proto(func_id, prog); 2009 return fn; 2010 } 2011 } 2012 2013 static bool raw_tp_prog_is_valid_access(int off, int size, 2014 enum bpf_access_type type, 2015 const struct bpf_prog *prog, 2016 struct bpf_insn_access_aux *info) 2017 { 2018 return bpf_tracing_ctx_access(off, size, type); 2019 } 2020 2021 static bool tracing_prog_is_valid_access(int off, int size, 2022 enum bpf_access_type type, 2023 const struct bpf_prog *prog, 2024 struct bpf_insn_access_aux *info) 2025 { 2026 return bpf_tracing_btf_ctx_access(off, size, type, prog, info); 2027 } 2028 2029 int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog, 2030 const union bpf_attr *kattr, 2031 union bpf_attr __user *uattr) 2032 { 2033 return -ENOTSUPP; 2034 } 2035 2036 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { 2037 .get_func_proto = raw_tp_prog_func_proto, 2038 .is_valid_access = raw_tp_prog_is_valid_access, 2039 }; 2040 2041 const struct bpf_prog_ops raw_tracepoint_prog_ops = { 2042 #ifdef CONFIG_NET 2043 .test_run = bpf_prog_test_run_raw_tp, 2044 #endif 2045 }; 2046 2047 const struct bpf_verifier_ops tracing_verifier_ops = { 2048 .get_func_proto = tracing_prog_func_proto, 2049 .is_valid_access = tracing_prog_is_valid_access, 2050 }; 2051 2052 const struct bpf_prog_ops tracing_prog_ops = { 2053 .test_run = bpf_prog_test_run_tracing, 2054 }; 2055 2056 static bool raw_tp_writable_prog_is_valid_access(int off, int size, 2057 enum bpf_access_type type, 2058 const struct bpf_prog *prog, 2059 struct bpf_insn_access_aux *info) 2060 { 2061 if (off == 0) { 2062 if (size != sizeof(u64) || type != BPF_READ) 2063 return false; 2064 info->reg_type = PTR_TO_TP_BUFFER; 2065 } 2066 return raw_tp_prog_is_valid_access(off, size, type, prog, info); 2067 } 2068 2069 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { 2070 .get_func_proto = raw_tp_prog_func_proto, 2071 .is_valid_access = raw_tp_writable_prog_is_valid_access, 2072 }; 2073 2074 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { 2075 }; 2076 2077 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 2078 const struct bpf_prog *prog, 2079 struct bpf_insn_access_aux *info) 2080 { 2081 const int size_u64 = sizeof(u64); 2082 2083 if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) 2084 return false; 2085 if (type != BPF_READ) 2086 return false; 2087 if (off % size != 0) { 2088 if (sizeof(unsigned long) != 4) 2089 return false; 2090 if (size != 8) 2091 return false; 2092 if (off % size != 4) 2093 return false; 2094 } 2095 2096 switch (off) { 2097 case bpf_ctx_range(struct bpf_perf_event_data, sample_period): 2098 bpf_ctx_record_field_size(info, size_u64); 2099 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 2100 return false; 2101 break; 2102 case bpf_ctx_range(struct bpf_perf_event_data, addr): 2103 bpf_ctx_record_field_size(info, size_u64); 2104 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 2105 return false; 2106 break; 2107 default: 2108 if (size != sizeof(long)) 2109 return false; 2110 } 2111 2112 return true; 2113 } 2114 2115 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, 2116 const struct bpf_insn *si, 2117 struct bpf_insn *insn_buf, 2118 struct bpf_prog *prog, u32 *target_size) 2119 { 2120 struct bpf_insn *insn = insn_buf; 2121 2122 switch (si->off) { 2123 case offsetof(struct bpf_perf_event_data, sample_period): 2124 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 2125 data), si->dst_reg, si->src_reg, 2126 offsetof(struct bpf_perf_event_data_kern, data)); 2127 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 2128 bpf_target_off(struct perf_sample_data, period, 8, 2129 target_size)); 2130 break; 2131 case offsetof(struct bpf_perf_event_data, addr): 2132 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 2133 data), si->dst_reg, si->src_reg, 2134 offsetof(struct bpf_perf_event_data_kern, data)); 2135 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 2136 bpf_target_off(struct perf_sample_data, addr, 8, 2137 target_size)); 2138 break; 2139 default: 2140 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 2141 regs), si->dst_reg, si->src_reg, 2142 offsetof(struct bpf_perf_event_data_kern, regs)); 2143 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, 2144 si->off); 2145 break; 2146 } 2147 2148 return insn - insn_buf; 2149 } 2150 2151 const struct bpf_verifier_ops perf_event_verifier_ops = { 2152 .get_func_proto = pe_prog_func_proto, 2153 .is_valid_access = pe_prog_is_valid_access, 2154 .convert_ctx_access = pe_prog_convert_ctx_access, 2155 }; 2156 2157 const struct bpf_prog_ops perf_event_prog_ops = { 2158 }; 2159 2160 static DEFINE_MUTEX(bpf_event_mutex); 2161 2162 #define BPF_TRACE_MAX_PROGS 64 2163 2164 int perf_event_attach_bpf_prog(struct perf_event *event, 2165 struct bpf_prog *prog, 2166 u64 bpf_cookie) 2167 { 2168 struct bpf_prog_array *old_array; 2169 struct bpf_prog_array *new_array; 2170 int ret = -EEXIST; 2171 2172 /* 2173 * Kprobe override only works if they are on the function entry, 2174 * and only if they are on the opt-in list. 2175 */ 2176 if (prog->kprobe_override && 2177 (!trace_kprobe_on_func_entry(event->tp_event) || 2178 !trace_kprobe_error_injectable(event->tp_event))) 2179 return -EINVAL; 2180 2181 mutex_lock(&bpf_event_mutex); 2182 2183 if (event->prog) 2184 goto unlock; 2185 2186 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 2187 if (old_array && 2188 bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { 2189 ret = -E2BIG; 2190 goto unlock; 2191 } 2192 2193 ret = bpf_prog_array_copy(old_array, NULL, prog, bpf_cookie, &new_array); 2194 if (ret < 0) 2195 goto unlock; 2196 2197 /* set the new array to event->tp_event and set event->prog */ 2198 event->prog = prog; 2199 event->bpf_cookie = bpf_cookie; 2200 rcu_assign_pointer(event->tp_event->prog_array, new_array); 2201 bpf_prog_array_free_sleepable(old_array); 2202 2203 unlock: 2204 mutex_unlock(&bpf_event_mutex); 2205 return ret; 2206 } 2207 2208 void perf_event_detach_bpf_prog(struct perf_event *event) 2209 { 2210 struct bpf_prog_array *old_array; 2211 struct bpf_prog_array *new_array; 2212 int ret; 2213 2214 mutex_lock(&bpf_event_mutex); 2215 2216 if (!event->prog) 2217 goto unlock; 2218 2219 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 2220 if (!old_array) 2221 goto put; 2222 2223 ret = bpf_prog_array_copy(old_array, event->prog, NULL, 0, &new_array); 2224 if (ret < 0) { 2225 bpf_prog_array_delete_safe(old_array, event->prog); 2226 } else { 2227 rcu_assign_pointer(event->tp_event->prog_array, new_array); 2228 bpf_prog_array_free_sleepable(old_array); 2229 } 2230 2231 put: 2232 /* 2233 * It could be that the bpf_prog is not sleepable (and will be freed 2234 * via normal RCU), but is called from a point that supports sleepable 2235 * programs and uses tasks-trace-RCU. 2236 */ 2237 synchronize_rcu_tasks_trace(); 2238 2239 bpf_prog_put(event->prog); 2240 event->prog = NULL; 2241 2242 unlock: 2243 mutex_unlock(&bpf_event_mutex); 2244 } 2245 2246 int perf_event_query_prog_array(struct perf_event *event, void __user *info) 2247 { 2248 struct perf_event_query_bpf __user *uquery = info; 2249 struct perf_event_query_bpf query = {}; 2250 struct bpf_prog_array *progs; 2251 u32 *ids, prog_cnt, ids_len; 2252 int ret; 2253 2254 if (!perfmon_capable()) 2255 return -EPERM; 2256 if (event->attr.type != PERF_TYPE_TRACEPOINT) 2257 return -EINVAL; 2258 if (copy_from_user(&query, uquery, sizeof(query))) 2259 return -EFAULT; 2260 2261 ids_len = query.ids_len; 2262 if (ids_len > BPF_TRACE_MAX_PROGS) 2263 return -E2BIG; 2264 ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); 2265 if (!ids) 2266 return -ENOMEM; 2267 /* 2268 * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which 2269 * is required when user only wants to check for uquery->prog_cnt. 2270 * There is no need to check for it since the case is handled 2271 * gracefully in bpf_prog_array_copy_info. 2272 */ 2273 2274 mutex_lock(&bpf_event_mutex); 2275 progs = bpf_event_rcu_dereference(event->tp_event->prog_array); 2276 ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt); 2277 mutex_unlock(&bpf_event_mutex); 2278 2279 if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || 2280 copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) 2281 ret = -EFAULT; 2282 2283 kfree(ids); 2284 return ret; 2285 } 2286 2287 extern struct bpf_raw_event_map __start__bpf_raw_tp[]; 2288 extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; 2289 2290 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) 2291 { 2292 struct bpf_raw_event_map *btp = __start__bpf_raw_tp; 2293 2294 for (; btp < __stop__bpf_raw_tp; btp++) { 2295 if (!strcmp(btp->tp->name, name)) 2296 return btp; 2297 } 2298 2299 return bpf_get_raw_tracepoint_module(name); 2300 } 2301 2302 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) 2303 { 2304 struct module *mod; 2305 2306 preempt_disable(); 2307 mod = __module_address((unsigned long)btp); 2308 module_put(mod); 2309 preempt_enable(); 2310 } 2311 2312 static __always_inline 2313 void __bpf_trace_run(struct bpf_prog *prog, u64 *args) 2314 { 2315 cant_sleep(); 2316 if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) { 2317 bpf_prog_inc_misses_counter(prog); 2318 goto out; 2319 } 2320 rcu_read_lock(); 2321 (void) bpf_prog_run(prog, args); 2322 rcu_read_unlock(); 2323 out: 2324 this_cpu_dec(*(prog->active)); 2325 } 2326 2327 #define UNPACK(...) __VA_ARGS__ 2328 #define REPEAT_1(FN, DL, X, ...) FN(X) 2329 #define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) 2330 #define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) 2331 #define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) 2332 #define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) 2333 #define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) 2334 #define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) 2335 #define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) 2336 #define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) 2337 #define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) 2338 #define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) 2339 #define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) 2340 #define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) 2341 2342 #define SARG(X) u64 arg##X 2343 #define COPY(X) args[X] = arg##X 2344 2345 #define __DL_COM (,) 2346 #define __DL_SEM (;) 2347 2348 #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 2349 2350 #define BPF_TRACE_DEFN_x(x) \ 2351 void bpf_trace_run##x(struct bpf_prog *prog, \ 2352 REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ 2353 { \ 2354 u64 args[x]; \ 2355 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ 2356 __bpf_trace_run(prog, args); \ 2357 } \ 2358 EXPORT_SYMBOL_GPL(bpf_trace_run##x) 2359 BPF_TRACE_DEFN_x(1); 2360 BPF_TRACE_DEFN_x(2); 2361 BPF_TRACE_DEFN_x(3); 2362 BPF_TRACE_DEFN_x(4); 2363 BPF_TRACE_DEFN_x(5); 2364 BPF_TRACE_DEFN_x(6); 2365 BPF_TRACE_DEFN_x(7); 2366 BPF_TRACE_DEFN_x(8); 2367 BPF_TRACE_DEFN_x(9); 2368 BPF_TRACE_DEFN_x(10); 2369 BPF_TRACE_DEFN_x(11); 2370 BPF_TRACE_DEFN_x(12); 2371 2372 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 2373 { 2374 struct tracepoint *tp = btp->tp; 2375 2376 /* 2377 * check that program doesn't access arguments beyond what's 2378 * available in this tracepoint 2379 */ 2380 if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) 2381 return -EINVAL; 2382 2383 if (prog->aux->max_tp_access > btp->writable_size) 2384 return -EINVAL; 2385 2386 return tracepoint_probe_register_may_exist(tp, (void *)btp->bpf_func, 2387 prog); 2388 } 2389 2390 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 2391 { 2392 return __bpf_probe_register(btp, prog); 2393 } 2394 2395 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 2396 { 2397 return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); 2398 } 2399 2400 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, 2401 u32 *fd_type, const char **buf, 2402 u64 *probe_offset, u64 *probe_addr, 2403 unsigned long *missed) 2404 { 2405 bool is_tracepoint, is_syscall_tp; 2406 struct bpf_prog *prog; 2407 int flags, err = 0; 2408 2409 prog = event->prog; 2410 if (!prog) 2411 return -ENOENT; 2412 2413 /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */ 2414 if (prog->type == BPF_PROG_TYPE_PERF_EVENT) 2415 return -EOPNOTSUPP; 2416 2417 *prog_id = prog->aux->id; 2418 flags = event->tp_event->flags; 2419 is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT; 2420 is_syscall_tp = is_syscall_trace_event(event->tp_event); 2421 2422 if (is_tracepoint || is_syscall_tp) { 2423 *buf = is_tracepoint ? event->tp_event->tp->name 2424 : event->tp_event->name; 2425 /* We allow NULL pointer for tracepoint */ 2426 if (fd_type) 2427 *fd_type = BPF_FD_TYPE_TRACEPOINT; 2428 if (probe_offset) 2429 *probe_offset = 0x0; 2430 if (probe_addr) 2431 *probe_addr = 0x0; 2432 } else { 2433 /* kprobe/uprobe */ 2434 err = -EOPNOTSUPP; 2435 #ifdef CONFIG_KPROBE_EVENTS 2436 if (flags & TRACE_EVENT_FL_KPROBE) 2437 err = bpf_get_kprobe_info(event, fd_type, buf, 2438 probe_offset, probe_addr, missed, 2439 event->attr.type == PERF_TYPE_TRACEPOINT); 2440 #endif 2441 #ifdef CONFIG_UPROBE_EVENTS 2442 if (flags & TRACE_EVENT_FL_UPROBE) 2443 err = bpf_get_uprobe_info(event, fd_type, buf, 2444 probe_offset, probe_addr, 2445 event->attr.type == PERF_TYPE_TRACEPOINT); 2446 #endif 2447 } 2448 2449 return err; 2450 } 2451 2452 static int __init send_signal_irq_work_init(void) 2453 { 2454 int cpu; 2455 struct send_signal_irq_work *work; 2456 2457 for_each_possible_cpu(cpu) { 2458 work = per_cpu_ptr(&send_signal_work, cpu); 2459 init_irq_work(&work->irq_work, do_bpf_send_signal); 2460 } 2461 return 0; 2462 } 2463 2464 subsys_initcall(send_signal_irq_work_init); 2465 2466 #ifdef CONFIG_MODULES 2467 static int bpf_event_notify(struct notifier_block *nb, unsigned long op, 2468 void *module) 2469 { 2470 struct bpf_trace_module *btm, *tmp; 2471 struct module *mod = module; 2472 int ret = 0; 2473 2474 if (mod->num_bpf_raw_events == 0 || 2475 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 2476 goto out; 2477 2478 mutex_lock(&bpf_module_mutex); 2479 2480 switch (op) { 2481 case MODULE_STATE_COMING: 2482 btm = kzalloc(sizeof(*btm), GFP_KERNEL); 2483 if (btm) { 2484 btm->module = module; 2485 list_add(&btm->list, &bpf_trace_modules); 2486 } else { 2487 ret = -ENOMEM; 2488 } 2489 break; 2490 case MODULE_STATE_GOING: 2491 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) { 2492 if (btm->module == module) { 2493 list_del(&btm->list); 2494 kfree(btm); 2495 break; 2496 } 2497 } 2498 break; 2499 } 2500 2501 mutex_unlock(&bpf_module_mutex); 2502 2503 out: 2504 return notifier_from_errno(ret); 2505 } 2506 2507 static struct notifier_block bpf_module_nb = { 2508 .notifier_call = bpf_event_notify, 2509 }; 2510 2511 static int __init bpf_event_init(void) 2512 { 2513 register_module_notifier(&bpf_module_nb); 2514 return 0; 2515 } 2516 2517 fs_initcall(bpf_event_init); 2518 #endif /* CONFIG_MODULES */ 2519 2520 #ifdef CONFIG_FPROBE 2521 struct bpf_kprobe_multi_link { 2522 struct bpf_link link; 2523 struct fprobe fp; 2524 unsigned long *addrs; 2525 u64 *cookies; 2526 u32 cnt; 2527 u32 mods_cnt; 2528 struct module **mods; 2529 u32 flags; 2530 }; 2531 2532 struct bpf_kprobe_multi_run_ctx { 2533 struct bpf_run_ctx run_ctx; 2534 struct bpf_kprobe_multi_link *link; 2535 unsigned long entry_ip; 2536 }; 2537 2538 struct user_syms { 2539 const char **syms; 2540 char *buf; 2541 }; 2542 2543 static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt) 2544 { 2545 unsigned long __user usymbol; 2546 const char **syms = NULL; 2547 char *buf = NULL, *p; 2548 int err = -ENOMEM; 2549 unsigned int i; 2550 2551 syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL); 2552 if (!syms) 2553 goto error; 2554 2555 buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL); 2556 if (!buf) 2557 goto error; 2558 2559 for (p = buf, i = 0; i < cnt; i++) { 2560 if (__get_user(usymbol, usyms + i)) { 2561 err = -EFAULT; 2562 goto error; 2563 } 2564 err = strncpy_from_user(p, (const char __user *) usymbol, KSYM_NAME_LEN); 2565 if (err == KSYM_NAME_LEN) 2566 err = -E2BIG; 2567 if (err < 0) 2568 goto error; 2569 syms[i] = p; 2570 p += err + 1; 2571 } 2572 2573 us->syms = syms; 2574 us->buf = buf; 2575 return 0; 2576 2577 error: 2578 if (err) { 2579 kvfree(syms); 2580 kvfree(buf); 2581 } 2582 return err; 2583 } 2584 2585 static void kprobe_multi_put_modules(struct module **mods, u32 cnt) 2586 { 2587 u32 i; 2588 2589 for (i = 0; i < cnt; i++) 2590 module_put(mods[i]); 2591 } 2592 2593 static void free_user_syms(struct user_syms *us) 2594 { 2595 kvfree(us->syms); 2596 kvfree(us->buf); 2597 } 2598 2599 static void bpf_kprobe_multi_link_release(struct bpf_link *link) 2600 { 2601 struct bpf_kprobe_multi_link *kmulti_link; 2602 2603 kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); 2604 unregister_fprobe(&kmulti_link->fp); 2605 kprobe_multi_put_modules(kmulti_link->mods, kmulti_link->mods_cnt); 2606 } 2607 2608 static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link) 2609 { 2610 struct bpf_kprobe_multi_link *kmulti_link; 2611 2612 kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); 2613 kvfree(kmulti_link->addrs); 2614 kvfree(kmulti_link->cookies); 2615 kfree(kmulti_link->mods); 2616 kfree(kmulti_link); 2617 } 2618 2619 static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link, 2620 struct bpf_link_info *info) 2621 { 2622 u64 __user *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs); 2623 struct bpf_kprobe_multi_link *kmulti_link; 2624 u32 ucount = info->kprobe_multi.count; 2625 int err = 0, i; 2626 2627 if (!uaddrs ^ !ucount) 2628 return -EINVAL; 2629 2630 kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); 2631 info->kprobe_multi.count = kmulti_link->cnt; 2632 info->kprobe_multi.flags = kmulti_link->flags; 2633 2634 if (!uaddrs) 2635 return 0; 2636 if (ucount < kmulti_link->cnt) 2637 err = -ENOSPC; 2638 else 2639 ucount = kmulti_link->cnt; 2640 2641 if (kallsyms_show_value(current_cred())) { 2642 if (copy_to_user(uaddrs, kmulti_link->addrs, ucount * sizeof(u64))) 2643 return -EFAULT; 2644 } else { 2645 for (i = 0; i < ucount; i++) { 2646 if (put_user(0, uaddrs + i)) 2647 return -EFAULT; 2648 } 2649 } 2650 return err; 2651 } 2652 2653 static const struct bpf_link_ops bpf_kprobe_multi_link_lops = { 2654 .release = bpf_kprobe_multi_link_release, 2655 .dealloc_deferred = bpf_kprobe_multi_link_dealloc, 2656 .fill_link_info = bpf_kprobe_multi_link_fill_link_info, 2657 }; 2658 2659 static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv) 2660 { 2661 const struct bpf_kprobe_multi_link *link = priv; 2662 unsigned long *addr_a = a, *addr_b = b; 2663 u64 *cookie_a, *cookie_b; 2664 2665 cookie_a = link->cookies + (addr_a - link->addrs); 2666 cookie_b = link->cookies + (addr_b - link->addrs); 2667 2668 /* swap addr_a/addr_b and cookie_a/cookie_b values */ 2669 swap(*addr_a, *addr_b); 2670 swap(*cookie_a, *cookie_b); 2671 } 2672 2673 static int bpf_kprobe_multi_addrs_cmp(const void *a, const void *b) 2674 { 2675 const unsigned long *addr_a = a, *addr_b = b; 2676 2677 if (*addr_a == *addr_b) 2678 return 0; 2679 return *addr_a < *addr_b ? -1 : 1; 2680 } 2681 2682 static int bpf_kprobe_multi_cookie_cmp(const void *a, const void *b, const void *priv) 2683 { 2684 return bpf_kprobe_multi_addrs_cmp(a, b); 2685 } 2686 2687 static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx) 2688 { 2689 struct bpf_kprobe_multi_run_ctx *run_ctx; 2690 struct bpf_kprobe_multi_link *link; 2691 u64 *cookie, entry_ip; 2692 unsigned long *addr; 2693 2694 if (WARN_ON_ONCE(!ctx)) 2695 return 0; 2696 run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx); 2697 link = run_ctx->link; 2698 if (!link->cookies) 2699 return 0; 2700 entry_ip = run_ctx->entry_ip; 2701 addr = bsearch(&entry_ip, link->addrs, link->cnt, sizeof(entry_ip), 2702 bpf_kprobe_multi_addrs_cmp); 2703 if (!addr) 2704 return 0; 2705 cookie = link->cookies + (addr - link->addrs); 2706 return *cookie; 2707 } 2708 2709 static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) 2710 { 2711 struct bpf_kprobe_multi_run_ctx *run_ctx; 2712 2713 run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx); 2714 return run_ctx->entry_ip; 2715 } 2716 2717 static int 2718 kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, 2719 unsigned long entry_ip, struct pt_regs *regs) 2720 { 2721 struct bpf_kprobe_multi_run_ctx run_ctx = { 2722 .link = link, 2723 .entry_ip = entry_ip, 2724 }; 2725 struct bpf_run_ctx *old_run_ctx; 2726 int err; 2727 2728 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { 2729 err = 0; 2730 goto out; 2731 } 2732 2733 migrate_disable(); 2734 rcu_read_lock(); 2735 old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); 2736 err = bpf_prog_run(link->link.prog, regs); 2737 bpf_reset_run_ctx(old_run_ctx); 2738 rcu_read_unlock(); 2739 migrate_enable(); 2740 2741 out: 2742 __this_cpu_dec(bpf_prog_active); 2743 return err; 2744 } 2745 2746 static int 2747 kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, 2748 unsigned long ret_ip, struct pt_regs *regs, 2749 void *data) 2750 { 2751 struct bpf_kprobe_multi_link *link; 2752 2753 link = container_of(fp, struct bpf_kprobe_multi_link, fp); 2754 kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); 2755 return 0; 2756 } 2757 2758 static void 2759 kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, 2760 unsigned long ret_ip, struct pt_regs *regs, 2761 void *data) 2762 { 2763 struct bpf_kprobe_multi_link *link; 2764 2765 link = container_of(fp, struct bpf_kprobe_multi_link, fp); 2766 kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); 2767 } 2768 2769 static int symbols_cmp_r(const void *a, const void *b, const void *priv) 2770 { 2771 const char **str_a = (const char **) a; 2772 const char **str_b = (const char **) b; 2773 2774 return strcmp(*str_a, *str_b); 2775 } 2776 2777 struct multi_symbols_sort { 2778 const char **funcs; 2779 u64 *cookies; 2780 }; 2781 2782 static void symbols_swap_r(void *a, void *b, int size, const void *priv) 2783 { 2784 const struct multi_symbols_sort *data = priv; 2785 const char **name_a = a, **name_b = b; 2786 2787 swap(*name_a, *name_b); 2788 2789 /* If defined, swap also related cookies. */ 2790 if (data->cookies) { 2791 u64 *cookie_a, *cookie_b; 2792 2793 cookie_a = data->cookies + (name_a - data->funcs); 2794 cookie_b = data->cookies + (name_b - data->funcs); 2795 swap(*cookie_a, *cookie_b); 2796 } 2797 } 2798 2799 struct modules_array { 2800 struct module **mods; 2801 int mods_cnt; 2802 int mods_cap; 2803 }; 2804 2805 static int add_module(struct modules_array *arr, struct module *mod) 2806 { 2807 struct module **mods; 2808 2809 if (arr->mods_cnt == arr->mods_cap) { 2810 arr->mods_cap = max(16, arr->mods_cap * 3 / 2); 2811 mods = krealloc_array(arr->mods, arr->mods_cap, sizeof(*mods), GFP_KERNEL); 2812 if (!mods) 2813 return -ENOMEM; 2814 arr->mods = mods; 2815 } 2816 2817 arr->mods[arr->mods_cnt] = mod; 2818 arr->mods_cnt++; 2819 return 0; 2820 } 2821 2822 static bool has_module(struct modules_array *arr, struct module *mod) 2823 { 2824 int i; 2825 2826 for (i = arr->mods_cnt - 1; i >= 0; i--) { 2827 if (arr->mods[i] == mod) 2828 return true; 2829 } 2830 return false; 2831 } 2832 2833 static int get_modules_for_addrs(struct module ***mods, unsigned long *addrs, u32 addrs_cnt) 2834 { 2835 struct modules_array arr = {}; 2836 u32 i, err = 0; 2837 2838 for (i = 0; i < addrs_cnt; i++) { 2839 struct module *mod; 2840 2841 preempt_disable(); 2842 mod = __module_address(addrs[i]); 2843 /* Either no module or we it's already stored */ 2844 if (!mod || has_module(&arr, mod)) { 2845 preempt_enable(); 2846 continue; 2847 } 2848 if (!try_module_get(mod)) 2849 err = -EINVAL; 2850 preempt_enable(); 2851 if (err) 2852 break; 2853 err = add_module(&arr, mod); 2854 if (err) { 2855 module_put(mod); 2856 break; 2857 } 2858 } 2859 2860 /* We return either err < 0 in case of error, ... */ 2861 if (err) { 2862 kprobe_multi_put_modules(arr.mods, arr.mods_cnt); 2863 kfree(arr.mods); 2864 return err; 2865 } 2866 2867 /* or number of modules found if everything is ok. */ 2868 *mods = arr.mods; 2869 return arr.mods_cnt; 2870 } 2871 2872 static int addrs_check_error_injection_list(unsigned long *addrs, u32 cnt) 2873 { 2874 u32 i; 2875 2876 for (i = 0; i < cnt; i++) { 2877 if (!within_error_injection_list(addrs[i])) 2878 return -EINVAL; 2879 } 2880 return 0; 2881 } 2882 2883 int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 2884 { 2885 struct bpf_kprobe_multi_link *link = NULL; 2886 struct bpf_link_primer link_primer; 2887 void __user *ucookies; 2888 unsigned long *addrs; 2889 u32 flags, cnt, size; 2890 void __user *uaddrs; 2891 u64 *cookies = NULL; 2892 void __user *usyms; 2893 int err; 2894 2895 /* no support for 32bit archs yet */ 2896 if (sizeof(u64) != sizeof(void *)) 2897 return -EOPNOTSUPP; 2898 2899 if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI) 2900 return -EINVAL; 2901 2902 flags = attr->link_create.kprobe_multi.flags; 2903 if (flags & ~BPF_F_KPROBE_MULTI_RETURN) 2904 return -EINVAL; 2905 2906 uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs); 2907 usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms); 2908 if (!!uaddrs == !!usyms) 2909 return -EINVAL; 2910 2911 cnt = attr->link_create.kprobe_multi.cnt; 2912 if (!cnt) 2913 return -EINVAL; 2914 if (cnt > MAX_KPROBE_MULTI_CNT) 2915 return -E2BIG; 2916 2917 size = cnt * sizeof(*addrs); 2918 addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL); 2919 if (!addrs) 2920 return -ENOMEM; 2921 2922 ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); 2923 if (ucookies) { 2924 cookies = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL); 2925 if (!cookies) { 2926 err = -ENOMEM; 2927 goto error; 2928 } 2929 if (copy_from_user(cookies, ucookies, size)) { 2930 err = -EFAULT; 2931 goto error; 2932 } 2933 } 2934 2935 if (uaddrs) { 2936 if (copy_from_user(addrs, uaddrs, size)) { 2937 err = -EFAULT; 2938 goto error; 2939 } 2940 } else { 2941 struct multi_symbols_sort data = { 2942 .cookies = cookies, 2943 }; 2944 struct user_syms us; 2945 2946 err = copy_user_syms(&us, usyms, cnt); 2947 if (err) 2948 goto error; 2949 2950 if (cookies) 2951 data.funcs = us.syms; 2952 2953 sort_r(us.syms, cnt, sizeof(*us.syms), symbols_cmp_r, 2954 symbols_swap_r, &data); 2955 2956 err = ftrace_lookup_symbols(us.syms, cnt, addrs); 2957 free_user_syms(&us); 2958 if (err) 2959 goto error; 2960 } 2961 2962 if (prog->kprobe_override && addrs_check_error_injection_list(addrs, cnt)) { 2963 err = -EINVAL; 2964 goto error; 2965 } 2966 2967 link = kzalloc(sizeof(*link), GFP_KERNEL); 2968 if (!link) { 2969 err = -ENOMEM; 2970 goto error; 2971 } 2972 2973 bpf_link_init(&link->link, BPF_LINK_TYPE_KPROBE_MULTI, 2974 &bpf_kprobe_multi_link_lops, prog); 2975 2976 err = bpf_link_prime(&link->link, &link_primer); 2977 if (err) 2978 goto error; 2979 2980 if (flags & BPF_F_KPROBE_MULTI_RETURN) 2981 link->fp.exit_handler = kprobe_multi_link_exit_handler; 2982 else 2983 link->fp.entry_handler = kprobe_multi_link_handler; 2984 2985 link->addrs = addrs; 2986 link->cookies = cookies; 2987 link->cnt = cnt; 2988 link->flags = flags; 2989 2990 if (cookies) { 2991 /* 2992 * Sorting addresses will trigger sorting cookies as well 2993 * (check bpf_kprobe_multi_cookie_swap). This way we can 2994 * find cookie based on the address in bpf_get_attach_cookie 2995 * helper. 2996 */ 2997 sort_r(addrs, cnt, sizeof(*addrs), 2998 bpf_kprobe_multi_cookie_cmp, 2999 bpf_kprobe_multi_cookie_swap, 3000 link); 3001 } 3002 3003 err = get_modules_for_addrs(&link->mods, addrs, cnt); 3004 if (err < 0) { 3005 bpf_link_cleanup(&link_primer); 3006 return err; 3007 } 3008 link->mods_cnt = err; 3009 3010 err = register_fprobe_ips(&link->fp, addrs, cnt); 3011 if (err) { 3012 kprobe_multi_put_modules(link->mods, link->mods_cnt); 3013 bpf_link_cleanup(&link_primer); 3014 return err; 3015 } 3016 3017 return bpf_link_settle(&link_primer); 3018 3019 error: 3020 kfree(link); 3021 kvfree(addrs); 3022 kvfree(cookies); 3023 return err; 3024 } 3025 #else /* !CONFIG_FPROBE */ 3026 int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 3027 { 3028 return -EOPNOTSUPP; 3029 } 3030 static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx) 3031 { 3032 return 0; 3033 } 3034 static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) 3035 { 3036 return 0; 3037 } 3038 #endif 3039 3040 #ifdef CONFIG_UPROBES 3041 struct bpf_uprobe_multi_link; 3042 3043 struct bpf_uprobe { 3044 struct bpf_uprobe_multi_link *link; 3045 loff_t offset; 3046 unsigned long ref_ctr_offset; 3047 u64 cookie; 3048 struct uprobe_consumer consumer; 3049 }; 3050 3051 struct bpf_uprobe_multi_link { 3052 struct path path; 3053 struct bpf_link link; 3054 u32 cnt; 3055 struct bpf_uprobe *uprobes; 3056 struct task_struct *task; 3057 }; 3058 3059 struct bpf_uprobe_multi_run_ctx { 3060 struct bpf_run_ctx run_ctx; 3061 unsigned long entry_ip; 3062 struct bpf_uprobe *uprobe; 3063 }; 3064 3065 static void bpf_uprobe_unregister(struct path *path, struct bpf_uprobe *uprobes, 3066 u32 cnt) 3067 { 3068 u32 i; 3069 3070 for (i = 0; i < cnt; i++) { 3071 uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset, 3072 &uprobes[i].consumer); 3073 } 3074 } 3075 3076 static void bpf_uprobe_multi_link_release(struct bpf_link *link) 3077 { 3078 struct bpf_uprobe_multi_link *umulti_link; 3079 3080 umulti_link = container_of(link, struct bpf_uprobe_multi_link, link); 3081 bpf_uprobe_unregister(&umulti_link->path, umulti_link->uprobes, umulti_link->cnt); 3082 if (umulti_link->task) 3083 put_task_struct(umulti_link->task); 3084 path_put(&umulti_link->path); 3085 } 3086 3087 static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link) 3088 { 3089 struct bpf_uprobe_multi_link *umulti_link; 3090 3091 umulti_link = container_of(link, struct bpf_uprobe_multi_link, link); 3092 kvfree(umulti_link->uprobes); 3093 kfree(umulti_link); 3094 } 3095 3096 static const struct bpf_link_ops bpf_uprobe_multi_link_lops = { 3097 .release = bpf_uprobe_multi_link_release, 3098 .dealloc_deferred = bpf_uprobe_multi_link_dealloc, 3099 }; 3100 3101 static int uprobe_prog_run(struct bpf_uprobe *uprobe, 3102 unsigned long entry_ip, 3103 struct pt_regs *regs) 3104 { 3105 struct bpf_uprobe_multi_link *link = uprobe->link; 3106 struct bpf_uprobe_multi_run_ctx run_ctx = { 3107 .entry_ip = entry_ip, 3108 .uprobe = uprobe, 3109 }; 3110 struct bpf_prog *prog = link->link.prog; 3111 bool sleepable = prog->aux->sleepable; 3112 struct bpf_run_ctx *old_run_ctx; 3113 3114 if (link->task && current->mm != link->task->mm) 3115 return 0; 3116 3117 if (sleepable) 3118 rcu_read_lock_trace(); 3119 else 3120 rcu_read_lock(); 3121 3122 migrate_disable(); 3123 3124 old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); 3125 bpf_prog_run(link->link.prog, regs); 3126 bpf_reset_run_ctx(old_run_ctx); 3127 3128 migrate_enable(); 3129 3130 if (sleepable) 3131 rcu_read_unlock_trace(); 3132 else 3133 rcu_read_unlock(); 3134 return 0; 3135 } 3136 3137 static bool 3138 uprobe_multi_link_filter(struct uprobe_consumer *con, enum uprobe_filter_ctx ctx, 3139 struct mm_struct *mm) 3140 { 3141 struct bpf_uprobe *uprobe; 3142 3143 uprobe = container_of(con, struct bpf_uprobe, consumer); 3144 return uprobe->link->task->mm == mm; 3145 } 3146 3147 static int 3148 uprobe_multi_link_handler(struct uprobe_consumer *con, struct pt_regs *regs) 3149 { 3150 struct bpf_uprobe *uprobe; 3151 3152 uprobe = container_of(con, struct bpf_uprobe, consumer); 3153 return uprobe_prog_run(uprobe, instruction_pointer(regs), regs); 3154 } 3155 3156 static int 3157 uprobe_multi_link_ret_handler(struct uprobe_consumer *con, unsigned long func, struct pt_regs *regs) 3158 { 3159 struct bpf_uprobe *uprobe; 3160 3161 uprobe = container_of(con, struct bpf_uprobe, consumer); 3162 return uprobe_prog_run(uprobe, func, regs); 3163 } 3164 3165 static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx) 3166 { 3167 struct bpf_uprobe_multi_run_ctx *run_ctx; 3168 3169 run_ctx = container_of(current->bpf_ctx, struct bpf_uprobe_multi_run_ctx, run_ctx); 3170 return run_ctx->entry_ip; 3171 } 3172 3173 static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx) 3174 { 3175 struct bpf_uprobe_multi_run_ctx *run_ctx; 3176 3177 run_ctx = container_of(current->bpf_ctx, struct bpf_uprobe_multi_run_ctx, run_ctx); 3178 return run_ctx->uprobe->cookie; 3179 } 3180 3181 int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 3182 { 3183 struct bpf_uprobe_multi_link *link = NULL; 3184 unsigned long __user *uref_ctr_offsets; 3185 struct bpf_link_primer link_primer; 3186 struct bpf_uprobe *uprobes = NULL; 3187 struct task_struct *task = NULL; 3188 unsigned long __user *uoffsets; 3189 u64 __user *ucookies; 3190 void __user *upath; 3191 u32 flags, cnt, i; 3192 struct path path; 3193 char *name; 3194 pid_t pid; 3195 int err; 3196 3197 /* no support for 32bit archs yet */ 3198 if (sizeof(u64) != sizeof(void *)) 3199 return -EOPNOTSUPP; 3200 3201 if (prog->expected_attach_type != BPF_TRACE_UPROBE_MULTI) 3202 return -EINVAL; 3203 3204 flags = attr->link_create.uprobe_multi.flags; 3205 if (flags & ~BPF_F_UPROBE_MULTI_RETURN) 3206 return -EINVAL; 3207 3208 /* 3209 * path, offsets and cnt are mandatory, 3210 * ref_ctr_offsets and cookies are optional 3211 */ 3212 upath = u64_to_user_ptr(attr->link_create.uprobe_multi.path); 3213 uoffsets = u64_to_user_ptr(attr->link_create.uprobe_multi.offsets); 3214 cnt = attr->link_create.uprobe_multi.cnt; 3215 pid = attr->link_create.uprobe_multi.pid; 3216 3217 if (!upath || !uoffsets || !cnt || pid < 0) 3218 return -EINVAL; 3219 if (cnt > MAX_UPROBE_MULTI_CNT) 3220 return -E2BIG; 3221 3222 uref_ctr_offsets = u64_to_user_ptr(attr->link_create.uprobe_multi.ref_ctr_offsets); 3223 ucookies = u64_to_user_ptr(attr->link_create.uprobe_multi.cookies); 3224 3225 name = strndup_user(upath, PATH_MAX); 3226 if (IS_ERR(name)) { 3227 err = PTR_ERR(name); 3228 return err; 3229 } 3230 3231 err = kern_path(name, LOOKUP_FOLLOW, &path); 3232 kfree(name); 3233 if (err) 3234 return err; 3235 3236 if (!d_is_reg(path.dentry)) { 3237 err = -EBADF; 3238 goto error_path_put; 3239 } 3240 3241 if (pid) { 3242 rcu_read_lock(); 3243 task = get_pid_task(find_vpid(pid), PIDTYPE_TGID); 3244 rcu_read_unlock(); 3245 if (!task) { 3246 err = -ESRCH; 3247 goto error_path_put; 3248 } 3249 } 3250 3251 err = -ENOMEM; 3252 3253 link = kzalloc(sizeof(*link), GFP_KERNEL); 3254 uprobes = kvcalloc(cnt, sizeof(*uprobes), GFP_KERNEL); 3255 3256 if (!uprobes || !link) 3257 goto error_free; 3258 3259 for (i = 0; i < cnt; i++) { 3260 if (ucookies && __get_user(uprobes[i].cookie, ucookies + i)) { 3261 err = -EFAULT; 3262 goto error_free; 3263 } 3264 if (uref_ctr_offsets && __get_user(uprobes[i].ref_ctr_offset, uref_ctr_offsets + i)) { 3265 err = -EFAULT; 3266 goto error_free; 3267 } 3268 if (__get_user(uprobes[i].offset, uoffsets + i)) { 3269 err = -EFAULT; 3270 goto error_free; 3271 } 3272 3273 uprobes[i].link = link; 3274 3275 if (flags & BPF_F_UPROBE_MULTI_RETURN) 3276 uprobes[i].consumer.ret_handler = uprobe_multi_link_ret_handler; 3277 else 3278 uprobes[i].consumer.handler = uprobe_multi_link_handler; 3279 3280 if (pid) 3281 uprobes[i].consumer.filter = uprobe_multi_link_filter; 3282 } 3283 3284 link->cnt = cnt; 3285 link->uprobes = uprobes; 3286 link->path = path; 3287 link->task = task; 3288 3289 bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI, 3290 &bpf_uprobe_multi_link_lops, prog); 3291 3292 for (i = 0; i < cnt; i++) { 3293 err = uprobe_register_refctr(d_real_inode(link->path.dentry), 3294 uprobes[i].offset, 3295 uprobes[i].ref_ctr_offset, 3296 &uprobes[i].consumer); 3297 if (err) { 3298 link->cnt = i; 3299 goto error_unregister; 3300 } 3301 } 3302 3303 err = bpf_link_prime(&link->link, &link_primer); 3304 if (err) 3305 goto error_unregister; 3306 3307 return bpf_link_settle(&link_primer); 3308 3309 error_unregister: 3310 bpf_uprobe_unregister(&path, uprobes, link->cnt); 3311 3312 error_free: 3313 kvfree(uprobes); 3314 kfree(link); 3315 if (task) 3316 put_task_struct(task); 3317 error_path_put: 3318 path_put(&path); 3319 return err; 3320 } 3321 #else /* !CONFIG_UPROBES */ 3322 int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 3323 { 3324 return -EOPNOTSUPP; 3325 } 3326 static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx) 3327 { 3328 return 0; 3329 } 3330 static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx) 3331 { 3332 return 0; 3333 } 3334 #endif /* CONFIG_UPROBES */ 3335