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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com | |
3 | * Copyright (c) 2016 Facebook | |
4 | */ | |
5 | #include <linux/kernel.h> | |
6 | #include <linux/types.h> | |
7 | #include <linux/slab.h> | |
8 | #include <linux/bpf.h> | |
9 | #include <linux/bpf_perf_event.h> | |
10 | #include <linux/filter.h> | |
11 | #include <linux/uaccess.h> | |
12 | #include <linux/ctype.h> | |
13 | #include <linux/kprobes.h> | |
14 | #include <linux/syscalls.h> | |
15 | #include <linux/error-injection.h> | |
16 | ||
17 | #include <asm/tlb.h> | |
18 | ||
19 | #include "trace_probe.h" | |
20 | #include "trace.h" | |
21 | ||
22 | #define bpf_event_rcu_dereference(p) \ | |
23 | rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) | |
24 | ||
25 | #ifdef CONFIG_MODULES | |
26 | struct bpf_trace_module { | |
27 | struct module *module; | |
28 | struct list_head list; | |
29 | }; | |
30 | ||
31 | static LIST_HEAD(bpf_trace_modules); | |
32 | static DEFINE_MUTEX(bpf_module_mutex); | |
33 | ||
34 | static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) | |
35 | { | |
36 | struct bpf_raw_event_map *btp, *ret = NULL; | |
37 | struct bpf_trace_module *btm; | |
38 | unsigned int i; | |
39 | ||
40 | mutex_lock(&bpf_module_mutex); | |
41 | list_for_each_entry(btm, &bpf_trace_modules, list) { | |
42 | for (i = 0; i < btm->module->num_bpf_raw_events; ++i) { | |
43 | btp = &btm->module->bpf_raw_events[i]; | |
44 | if (!strcmp(btp->tp->name, name)) { | |
45 | if (try_module_get(btm->module)) | |
46 | ret = btp; | |
47 | goto out; | |
48 | } | |
49 | } | |
50 | } | |
51 | out: | |
52 | mutex_unlock(&bpf_module_mutex); | |
53 | return ret; | |
54 | } | |
55 | #else | |
56 | static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) | |
57 | { | |
58 | return NULL; | |
59 | } | |
60 | #endif /* CONFIG_MODULES */ | |
61 | ||
62 | u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); | |
63 | u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); | |
64 | ||
65 | /** | |
66 | * trace_call_bpf - invoke BPF program | |
67 | * @call: tracepoint event | |
68 | * @ctx: opaque context pointer | |
69 | * | |
70 | * kprobe handlers execute BPF programs via this helper. | |
71 | * Can be used from static tracepoints in the future. | |
72 | * | |
73 | * Return: BPF programs always return an integer which is interpreted by | |
74 | * kprobe handler as: | |
75 | * 0 - return from kprobe (event is filtered out) | |
76 | * 1 - store kprobe event into ring buffer | |
77 | * Other values are reserved and currently alias to 1 | |
78 | */ | |
79 | unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) | |
80 | { | |
81 | unsigned int ret; | |
82 | ||
83 | if (in_nmi()) /* not supported yet */ | |
84 | return 1; | |
85 | ||
86 | preempt_disable(); | |
87 | ||
88 | if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { | |
89 | /* | |
90 | * since some bpf program is already running on this cpu, | |
91 | * don't call into another bpf program (same or different) | |
92 | * and don't send kprobe event into ring-buffer, | |
93 | * so return zero here | |
94 | */ | |
95 | ret = 0; | |
96 | goto out; | |
97 | } | |
98 | ||
99 | /* | |
100 | * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock | |
101 | * to all call sites, we did a bpf_prog_array_valid() there to check | |
102 | * whether call->prog_array is empty or not, which is | |
103 | * a heurisitc to speed up execution. | |
104 | * | |
105 | * If bpf_prog_array_valid() fetched prog_array was | |
106 | * non-NULL, we go into trace_call_bpf() and do the actual | |
107 | * proper rcu_dereference() under RCU lock. | |
108 | * If it turns out that prog_array is NULL then, we bail out. | |
109 | * For the opposite, if the bpf_prog_array_valid() fetched pointer | |
110 | * was NULL, you'll skip the prog_array with the risk of missing | |
111 | * out of events when it was updated in between this and the | |
112 | * rcu_dereference() which is accepted risk. | |
113 | */ | |
114 | ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN); | |
115 | ||
116 | out: | |
117 | __this_cpu_dec(bpf_prog_active); | |
118 | preempt_enable(); | |
119 | ||
120 | return ret; | |
121 | } | |
122 | EXPORT_SYMBOL_GPL(trace_call_bpf); | |
123 | ||
124 | #ifdef CONFIG_BPF_KPROBE_OVERRIDE | |
125 | BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) | |
126 | { | |
127 | regs_set_return_value(regs, rc); | |
128 | override_function_with_return(regs); | |
129 | return 0; | |
130 | } | |
131 | ||
132 | static const struct bpf_func_proto bpf_override_return_proto = { | |
133 | .func = bpf_override_return, | |
134 | .gpl_only = true, | |
135 | .ret_type = RET_INTEGER, | |
136 | .arg1_type = ARG_PTR_TO_CTX, | |
137 | .arg2_type = ARG_ANYTHING, | |
138 | }; | |
139 | #endif | |
140 | ||
141 | BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) | |
142 | { | |
143 | int ret; | |
144 | ||
145 | ret = security_locked_down(LOCKDOWN_BPF_READ); | |
146 | if (ret < 0) | |
147 | goto out; | |
148 | ||
149 | ret = probe_kernel_read(dst, unsafe_ptr, size); | |
150 | if (unlikely(ret < 0)) | |
151 | out: | |
152 | memset(dst, 0, size); | |
153 | ||
154 | return ret; | |
155 | } | |
156 | ||
157 | static const struct bpf_func_proto bpf_probe_read_proto = { | |
158 | .func = bpf_probe_read, | |
159 | .gpl_only = true, | |
160 | .ret_type = RET_INTEGER, | |
161 | .arg1_type = ARG_PTR_TO_UNINIT_MEM, | |
162 | .arg2_type = ARG_CONST_SIZE_OR_ZERO, | |
163 | .arg3_type = ARG_ANYTHING, | |
164 | }; | |
165 | ||
166 | BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, | |
167 | u32, size) | |
168 | { | |
169 | /* | |
170 | * Ensure we're in user context which is safe for the helper to | |
171 | * run. This helper has no business in a kthread. | |
172 | * | |
173 | * access_ok() should prevent writing to non-user memory, but in | |
174 | * some situations (nommu, temporary switch, etc) access_ok() does | |
175 | * not provide enough validation, hence the check on KERNEL_DS. | |
176 | * | |
177 | * nmi_uaccess_okay() ensures the probe is not run in an interim | |
178 | * state, when the task or mm are switched. This is specifically | |
179 | * required to prevent the use of temporary mm. | |
180 | */ | |
181 | ||
182 | if (unlikely(in_interrupt() || | |
183 | current->flags & (PF_KTHREAD | PF_EXITING))) | |
184 | return -EPERM; | |
185 | if (unlikely(uaccess_kernel())) | |
186 | return -EPERM; | |
187 | if (unlikely(!nmi_uaccess_okay())) | |
188 | return -EPERM; | |
189 | if (!access_ok(unsafe_ptr, size)) | |
190 | return -EPERM; | |
191 | ||
192 | return probe_kernel_write(unsafe_ptr, src, size); | |
193 | } | |
194 | ||
195 | static const struct bpf_func_proto bpf_probe_write_user_proto = { | |
196 | .func = bpf_probe_write_user, | |
197 | .gpl_only = true, | |
198 | .ret_type = RET_INTEGER, | |
199 | .arg1_type = ARG_ANYTHING, | |
200 | .arg2_type = ARG_PTR_TO_MEM, | |
201 | .arg3_type = ARG_CONST_SIZE, | |
202 | }; | |
203 | ||
204 | static const struct bpf_func_proto *bpf_get_probe_write_proto(void) | |
205 | { | |
206 | pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", | |
207 | current->comm, task_pid_nr(current)); | |
208 | ||
209 | return &bpf_probe_write_user_proto; | |
210 | } | |
211 | ||
212 | /* | |
213 | * Only limited trace_printk() conversion specifiers allowed: | |
214 | * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s | |
215 | */ | |
216 | BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, | |
217 | u64, arg2, u64, arg3) | |
218 | { | |
219 | bool str_seen = false; | |
220 | int mod[3] = {}; | |
221 | int fmt_cnt = 0; | |
222 | u64 unsafe_addr; | |
223 | char buf[64]; | |
224 | int i; | |
225 | ||
226 | /* | |
227 | * bpf_check()->check_func_arg()->check_stack_boundary() | |
228 | * guarantees that fmt points to bpf program stack, | |
229 | * fmt_size bytes of it were initialized and fmt_size > 0 | |
230 | */ | |
231 | if (fmt[--fmt_size] != 0) | |
232 | return -EINVAL; | |
233 | ||
234 | /* check format string for allowed specifiers */ | |
235 | for (i = 0; i < fmt_size; i++) { | |
236 | if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) | |
237 | return -EINVAL; | |
238 | ||
239 | if (fmt[i] != '%') | |
240 | continue; | |
241 | ||
242 | if (fmt_cnt >= 3) | |
243 | return -EINVAL; | |
244 | ||
245 | /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ | |
246 | i++; | |
247 | if (fmt[i] == 'l') { | |
248 | mod[fmt_cnt]++; | |
249 | i++; | |
250 | } else if (fmt[i] == 'p' || fmt[i] == 's') { | |
251 | mod[fmt_cnt]++; | |
252 | /* disallow any further format extensions */ | |
253 | if (fmt[i + 1] != 0 && | |
254 | !isspace(fmt[i + 1]) && | |
255 | !ispunct(fmt[i + 1])) | |
256 | return -EINVAL; | |
257 | fmt_cnt++; | |
258 | if (fmt[i] == 's') { | |
259 | if (str_seen) | |
260 | /* allow only one '%s' per fmt string */ | |
261 | return -EINVAL; | |
262 | str_seen = true; | |
263 | ||
264 | switch (fmt_cnt) { | |
265 | case 1: | |
266 | unsafe_addr = arg1; | |
267 | arg1 = (long) buf; | |
268 | break; | |
269 | case 2: | |
270 | unsafe_addr = arg2; | |
271 | arg2 = (long) buf; | |
272 | break; | |
273 | case 3: | |
274 | unsafe_addr = arg3; | |
275 | arg3 = (long) buf; | |
276 | break; | |
277 | } | |
278 | buf[0] = 0; | |
279 | strncpy_from_unsafe(buf, | |
280 | (void *) (long) unsafe_addr, | |
281 | sizeof(buf)); | |
282 | } | |
283 | continue; | |
284 | } | |
285 | ||
286 | if (fmt[i] == 'l') { | |
287 | mod[fmt_cnt]++; | |
288 | i++; | |
289 | } | |
290 | ||
291 | if (fmt[i] != 'i' && fmt[i] != 'd' && | |
292 | fmt[i] != 'u' && fmt[i] != 'x') | |
293 | return -EINVAL; | |
294 | fmt_cnt++; | |
295 | } | |
296 | ||
297 | /* Horrid workaround for getting va_list handling working with different | |
298 | * argument type combinations generically for 32 and 64 bit archs. | |
299 | */ | |
300 | #define __BPF_TP_EMIT() __BPF_ARG3_TP() | |
301 | #define __BPF_TP(...) \ | |
302 | __trace_printk(0 /* Fake ip */, \ | |
303 | fmt, ##__VA_ARGS__) | |
304 | ||
305 | #define __BPF_ARG1_TP(...) \ | |
306 | ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ | |
307 | ? __BPF_TP(arg1, ##__VA_ARGS__) \ | |
308 | : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ | |
309 | ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ | |
310 | : __BPF_TP((u32)arg1, ##__VA_ARGS__))) | |
311 | ||
312 | #define __BPF_ARG2_TP(...) \ | |
313 | ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ | |
314 | ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ | |
315 | : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ | |
316 | ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ | |
317 | : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) | |
318 | ||
319 | #define __BPF_ARG3_TP(...) \ | |
320 | ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ | |
321 | ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ | |
322 | : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ | |
323 | ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ | |
324 | : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) | |
325 | ||
326 | return __BPF_TP_EMIT(); | |
327 | } | |
328 | ||
329 | static const struct bpf_func_proto bpf_trace_printk_proto = { | |
330 | .func = bpf_trace_printk, | |
331 | .gpl_only = true, | |
332 | .ret_type = RET_INTEGER, | |
333 | .arg1_type = ARG_PTR_TO_MEM, | |
334 | .arg2_type = ARG_CONST_SIZE, | |
335 | }; | |
336 | ||
337 | const struct bpf_func_proto *bpf_get_trace_printk_proto(void) | |
338 | { | |
339 | /* | |
340 | * this program might be calling bpf_trace_printk, | |
341 | * so allocate per-cpu printk buffers | |
342 | */ | |
343 | trace_printk_init_buffers(); | |
344 | ||
345 | return &bpf_trace_printk_proto; | |
346 | } | |
347 | ||
348 | static __always_inline int | |
349 | get_map_perf_counter(struct bpf_map *map, u64 flags, | |
350 | u64 *value, u64 *enabled, u64 *running) | |
351 | { | |
352 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
353 | unsigned int cpu = smp_processor_id(); | |
354 | u64 index = flags & BPF_F_INDEX_MASK; | |
355 | struct bpf_event_entry *ee; | |
356 | ||
357 | if (unlikely(flags & ~(BPF_F_INDEX_MASK))) | |
358 | return -EINVAL; | |
359 | if (index == BPF_F_CURRENT_CPU) | |
360 | index = cpu; | |
361 | if (unlikely(index >= array->map.max_entries)) | |
362 | return -E2BIG; | |
363 | ||
364 | ee = READ_ONCE(array->ptrs[index]); | |
365 | if (!ee) | |
366 | return -ENOENT; | |
367 | ||
368 | return perf_event_read_local(ee->event, value, enabled, running); | |
369 | } | |
370 | ||
371 | BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) | |
372 | { | |
373 | u64 value = 0; | |
374 | int err; | |
375 | ||
376 | err = get_map_perf_counter(map, flags, &value, NULL, NULL); | |
377 | /* | |
378 | * this api is ugly since we miss [-22..-2] range of valid | |
379 | * counter values, but that's uapi | |
380 | */ | |
381 | if (err) | |
382 | return err; | |
383 | return value; | |
384 | } | |
385 | ||
386 | static const struct bpf_func_proto bpf_perf_event_read_proto = { | |
387 | .func = bpf_perf_event_read, | |
388 | .gpl_only = true, | |
389 | .ret_type = RET_INTEGER, | |
390 | .arg1_type = ARG_CONST_MAP_PTR, | |
391 | .arg2_type = ARG_ANYTHING, | |
392 | }; | |
393 | ||
394 | BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags, | |
395 | struct bpf_perf_event_value *, buf, u32, size) | |
396 | { | |
397 | int err = -EINVAL; | |
398 | ||
399 | if (unlikely(size != sizeof(struct bpf_perf_event_value))) | |
400 | goto clear; | |
401 | err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled, | |
402 | &buf->running); | |
403 | if (unlikely(err)) | |
404 | goto clear; | |
405 | return 0; | |
406 | clear: | |
407 | memset(buf, 0, size); | |
408 | return err; | |
409 | } | |
410 | ||
411 | static const struct bpf_func_proto bpf_perf_event_read_value_proto = { | |
412 | .func = bpf_perf_event_read_value, | |
413 | .gpl_only = true, | |
414 | .ret_type = RET_INTEGER, | |
415 | .arg1_type = ARG_CONST_MAP_PTR, | |
416 | .arg2_type = ARG_ANYTHING, | |
417 | .arg3_type = ARG_PTR_TO_UNINIT_MEM, | |
418 | .arg4_type = ARG_CONST_SIZE, | |
419 | }; | |
420 | ||
421 | static __always_inline u64 | |
422 | __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, | |
423 | u64 flags, struct perf_sample_data *sd) | |
424 | { | |
425 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
426 | unsigned int cpu = smp_processor_id(); | |
427 | u64 index = flags & BPF_F_INDEX_MASK; | |
428 | struct bpf_event_entry *ee; | |
429 | struct perf_event *event; | |
430 | ||
431 | if (index == BPF_F_CURRENT_CPU) | |
432 | index = cpu; | |
433 | if (unlikely(index >= array->map.max_entries)) | |
434 | return -E2BIG; | |
435 | ||
436 | ee = READ_ONCE(array->ptrs[index]); | |
437 | if (!ee) | |
438 | return -ENOENT; | |
439 | ||
440 | event = ee->event; | |
441 | if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || | |
442 | event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) | |
443 | return -EINVAL; | |
444 | ||
445 | if (unlikely(event->oncpu != cpu)) | |
446 | return -EOPNOTSUPP; | |
447 | ||
448 | return perf_event_output(event, sd, regs); | |
449 | } | |
450 | ||
451 | /* | |
452 | * Support executing tracepoints in normal, irq, and nmi context that each call | |
453 | * bpf_perf_event_output | |
454 | */ | |
455 | struct bpf_trace_sample_data { | |
456 | struct perf_sample_data sds[3]; | |
457 | }; | |
458 | ||
459 | static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); | |
460 | static DEFINE_PER_CPU(int, bpf_trace_nest_level); | |
461 | BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, | |
462 | u64, flags, void *, data, u64, size) | |
463 | { | |
464 | struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds); | |
465 | int nest_level = this_cpu_inc_return(bpf_trace_nest_level); | |
466 | struct perf_raw_record raw = { | |
467 | .frag = { | |
468 | .size = size, | |
469 | .data = data, | |
470 | }, | |
471 | }; | |
472 | struct perf_sample_data *sd; | |
473 | int err; | |
474 | ||
475 | if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { | |
476 | err = -EBUSY; | |
477 | goto out; | |
478 | } | |
479 | ||
480 | sd = &sds->sds[nest_level - 1]; | |
481 | ||
482 | if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { | |
483 | err = -EINVAL; | |
484 | goto out; | |
485 | } | |
486 | ||
487 | perf_sample_data_init(sd, 0, 0); | |
488 | sd->raw = &raw; | |
489 | ||
490 | err = __bpf_perf_event_output(regs, map, flags, sd); | |
491 | ||
492 | out: | |
493 | this_cpu_dec(bpf_trace_nest_level); | |
494 | return err; | |
495 | } | |
496 | ||
497 | static const struct bpf_func_proto bpf_perf_event_output_proto = { | |
498 | .func = bpf_perf_event_output, | |
499 | .gpl_only = true, | |
500 | .ret_type = RET_INTEGER, | |
501 | .arg1_type = ARG_PTR_TO_CTX, | |
502 | .arg2_type = ARG_CONST_MAP_PTR, | |
503 | .arg3_type = ARG_ANYTHING, | |
504 | .arg4_type = ARG_PTR_TO_MEM, | |
505 | .arg5_type = ARG_CONST_SIZE_OR_ZERO, | |
506 | }; | |
507 | ||
508 | static DEFINE_PER_CPU(int, bpf_event_output_nest_level); | |
509 | struct bpf_nested_pt_regs { | |
510 | struct pt_regs regs[3]; | |
511 | }; | |
512 | static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs); | |
513 | static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds); | |
514 | ||
515 | u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, | |
516 | void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) | |
517 | { | |
518 | int nest_level = this_cpu_inc_return(bpf_event_output_nest_level); | |
519 | struct perf_raw_frag frag = { | |
520 | .copy = ctx_copy, | |
521 | .size = ctx_size, | |
522 | .data = ctx, | |
523 | }; | |
524 | struct perf_raw_record raw = { | |
525 | .frag = { | |
526 | { | |
527 | .next = ctx_size ? &frag : NULL, | |
528 | }, | |
529 | .size = meta_size, | |
530 | .data = meta, | |
531 | }, | |
532 | }; | |
533 | struct perf_sample_data *sd; | |
534 | struct pt_regs *regs; | |
535 | u64 ret; | |
536 | ||
537 | if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) { | |
538 | ret = -EBUSY; | |
539 | goto out; | |
540 | } | |
541 | sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]); | |
542 | regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]); | |
543 | ||
544 | perf_fetch_caller_regs(regs); | |
545 | perf_sample_data_init(sd, 0, 0); | |
546 | sd->raw = &raw; | |
547 | ||
548 | ret = __bpf_perf_event_output(regs, map, flags, sd); | |
549 | out: | |
550 | this_cpu_dec(bpf_event_output_nest_level); | |
551 | return ret; | |
552 | } | |
553 | ||
554 | BPF_CALL_0(bpf_get_current_task) | |
555 | { | |
556 | return (long) current; | |
557 | } | |
558 | ||
559 | static const struct bpf_func_proto bpf_get_current_task_proto = { | |
560 | .func = bpf_get_current_task, | |
561 | .gpl_only = true, | |
562 | .ret_type = RET_INTEGER, | |
563 | }; | |
564 | ||
565 | BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) | |
566 | { | |
567 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
568 | struct cgroup *cgrp; | |
569 | ||
570 | if (unlikely(idx >= array->map.max_entries)) | |
571 | return -E2BIG; | |
572 | ||
573 | cgrp = READ_ONCE(array->ptrs[idx]); | |
574 | if (unlikely(!cgrp)) | |
575 | return -EAGAIN; | |
576 | ||
577 | return task_under_cgroup_hierarchy(current, cgrp); | |
578 | } | |
579 | ||
580 | static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { | |
581 | .func = bpf_current_task_under_cgroup, | |
582 | .gpl_only = false, | |
583 | .ret_type = RET_INTEGER, | |
584 | .arg1_type = ARG_CONST_MAP_PTR, | |
585 | .arg2_type = ARG_ANYTHING, | |
586 | }; | |
587 | ||
588 | BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size, | |
589 | const void *, unsafe_ptr) | |
590 | { | |
591 | int ret; | |
592 | ||
593 | ret = security_locked_down(LOCKDOWN_BPF_READ); | |
594 | if (ret < 0) | |
595 | goto out; | |
596 | ||
597 | /* | |
598 | * The strncpy_from_unsafe() call will likely not fill the entire | |
599 | * buffer, but that's okay in this circumstance as we're probing | |
600 | * arbitrary memory anyway similar to bpf_probe_read() and might | |
601 | * as well probe the stack. Thus, memory is explicitly cleared | |
602 | * only in error case, so that improper users ignoring return | |
603 | * code altogether don't copy garbage; otherwise length of string | |
604 | * is returned that can be used for bpf_perf_event_output() et al. | |
605 | */ | |
606 | ret = strncpy_from_unsafe(dst, unsafe_ptr, size); | |
607 | if (unlikely(ret < 0)) | |
608 | out: | |
609 | memset(dst, 0, size); | |
610 | ||
611 | return ret; | |
612 | } | |
613 | ||
614 | static const struct bpf_func_proto bpf_probe_read_str_proto = { | |
615 | .func = bpf_probe_read_str, | |
616 | .gpl_only = true, | |
617 | .ret_type = RET_INTEGER, | |
618 | .arg1_type = ARG_PTR_TO_UNINIT_MEM, | |
619 | .arg2_type = ARG_CONST_SIZE_OR_ZERO, | |
620 | .arg3_type = ARG_ANYTHING, | |
621 | }; | |
622 | ||
623 | struct send_signal_irq_work { | |
624 | struct irq_work irq_work; | |
625 | struct task_struct *task; | |
626 | u32 sig; | |
627 | }; | |
628 | ||
629 | static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); | |
630 | ||
631 | static void do_bpf_send_signal(struct irq_work *entry) | |
632 | { | |
633 | struct send_signal_irq_work *work; | |
634 | ||
635 | work = container_of(entry, struct send_signal_irq_work, irq_work); | |
636 | group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, PIDTYPE_TGID); | |
637 | } | |
638 | ||
639 | BPF_CALL_1(bpf_send_signal, u32, sig) | |
640 | { | |
641 | struct send_signal_irq_work *work = NULL; | |
642 | ||
643 | /* Similar to bpf_probe_write_user, task needs to be | |
644 | * in a sound condition and kernel memory access be | |
645 | * permitted in order to send signal to the current | |
646 | * task. | |
647 | */ | |
648 | if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) | |
649 | return -EPERM; | |
650 | if (unlikely(uaccess_kernel())) | |
651 | return -EPERM; | |
652 | if (unlikely(!nmi_uaccess_okay())) | |
653 | return -EPERM; | |
654 | ||
655 | if (in_nmi()) { | |
656 | /* Do an early check on signal validity. Otherwise, | |
657 | * the error is lost in deferred irq_work. | |
658 | */ | |
659 | if (unlikely(!valid_signal(sig))) | |
660 | return -EINVAL; | |
661 | ||
662 | work = this_cpu_ptr(&send_signal_work); | |
663 | if (work->irq_work.flags & IRQ_WORK_BUSY) | |
664 | return -EBUSY; | |
665 | ||
666 | /* Add the current task, which is the target of sending signal, | |
667 | * to the irq_work. The current task may change when queued | |
668 | * irq works get executed. | |
669 | */ | |
670 | work->task = current; | |
671 | work->sig = sig; | |
672 | irq_work_queue(&work->irq_work); | |
673 | return 0; | |
674 | } | |
675 | ||
676 | return group_send_sig_info(sig, SEND_SIG_PRIV, current, PIDTYPE_TGID); | |
677 | } | |
678 | ||
679 | static const struct bpf_func_proto bpf_send_signal_proto = { | |
680 | .func = bpf_send_signal, | |
681 | .gpl_only = false, | |
682 | .ret_type = RET_INTEGER, | |
683 | .arg1_type = ARG_ANYTHING, | |
684 | }; | |
685 | ||
686 | static const struct bpf_func_proto * | |
687 | tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) | |
688 | { | |
689 | switch (func_id) { | |
690 | case BPF_FUNC_map_lookup_elem: | |
691 | return &bpf_map_lookup_elem_proto; | |
692 | case BPF_FUNC_map_update_elem: | |
693 | return &bpf_map_update_elem_proto; | |
694 | case BPF_FUNC_map_delete_elem: | |
695 | return &bpf_map_delete_elem_proto; | |
696 | case BPF_FUNC_map_push_elem: | |
697 | return &bpf_map_push_elem_proto; | |
698 | case BPF_FUNC_map_pop_elem: | |
699 | return &bpf_map_pop_elem_proto; | |
700 | case BPF_FUNC_map_peek_elem: | |
701 | return &bpf_map_peek_elem_proto; | |
702 | case BPF_FUNC_probe_read: | |
703 | return &bpf_probe_read_proto; | |
704 | case BPF_FUNC_ktime_get_ns: | |
705 | return &bpf_ktime_get_ns_proto; | |
706 | case BPF_FUNC_tail_call: | |
707 | return &bpf_tail_call_proto; | |
708 | case BPF_FUNC_get_current_pid_tgid: | |
709 | return &bpf_get_current_pid_tgid_proto; | |
710 | case BPF_FUNC_get_current_task: | |
711 | return &bpf_get_current_task_proto; | |
712 | case BPF_FUNC_get_current_uid_gid: | |
713 | return &bpf_get_current_uid_gid_proto; | |
714 | case BPF_FUNC_get_current_comm: | |
715 | return &bpf_get_current_comm_proto; | |
716 | case BPF_FUNC_trace_printk: | |
717 | return bpf_get_trace_printk_proto(); | |
718 | case BPF_FUNC_get_smp_processor_id: | |
719 | return &bpf_get_smp_processor_id_proto; | |
720 | case BPF_FUNC_get_numa_node_id: | |
721 | return &bpf_get_numa_node_id_proto; | |
722 | case BPF_FUNC_perf_event_read: | |
723 | return &bpf_perf_event_read_proto; | |
724 | case BPF_FUNC_probe_write_user: | |
725 | return bpf_get_probe_write_proto(); | |
726 | case BPF_FUNC_current_task_under_cgroup: | |
727 | return &bpf_current_task_under_cgroup_proto; | |
728 | case BPF_FUNC_get_prandom_u32: | |
729 | return &bpf_get_prandom_u32_proto; | |
730 | case BPF_FUNC_probe_read_str: | |
731 | return &bpf_probe_read_str_proto; | |
732 | #ifdef CONFIG_CGROUPS | |
733 | case BPF_FUNC_get_current_cgroup_id: | |
734 | return &bpf_get_current_cgroup_id_proto; | |
735 | #endif | |
736 | case BPF_FUNC_send_signal: | |
737 | return &bpf_send_signal_proto; | |
738 | default: | |
739 | return NULL; | |
740 | } | |
741 | } | |
742 | ||
743 | static const struct bpf_func_proto * | |
744 | kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) | |
745 | { | |
746 | switch (func_id) { | |
747 | case BPF_FUNC_perf_event_output: | |
748 | return &bpf_perf_event_output_proto; | |
749 | case BPF_FUNC_get_stackid: | |
750 | return &bpf_get_stackid_proto; | |
751 | case BPF_FUNC_get_stack: | |
752 | return &bpf_get_stack_proto; | |
753 | case BPF_FUNC_perf_event_read_value: | |
754 | return &bpf_perf_event_read_value_proto; | |
755 | #ifdef CONFIG_BPF_KPROBE_OVERRIDE | |
756 | case BPF_FUNC_override_return: | |
757 | return &bpf_override_return_proto; | |
758 | #endif | |
759 | default: | |
760 | return tracing_func_proto(func_id, prog); | |
761 | } | |
762 | } | |
763 | ||
764 | /* bpf+kprobe programs can access fields of 'struct pt_regs' */ | |
765 | static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, | |
766 | const struct bpf_prog *prog, | |
767 | struct bpf_insn_access_aux *info) | |
768 | { | |
769 | if (off < 0 || off >= sizeof(struct pt_regs)) | |
770 | return false; | |
771 | if (type != BPF_READ) | |
772 | return false; | |
773 | if (off % size != 0) | |
774 | return false; | |
775 | /* | |
776 | * Assertion for 32 bit to make sure last 8 byte access | |
777 | * (BPF_DW) to the last 4 byte member is disallowed. | |
778 | */ | |
779 | if (off + size > sizeof(struct pt_regs)) | |
780 | return false; | |
781 | ||
782 | return true; | |
783 | } | |
784 | ||
785 | const struct bpf_verifier_ops kprobe_verifier_ops = { | |
786 | .get_func_proto = kprobe_prog_func_proto, | |
787 | .is_valid_access = kprobe_prog_is_valid_access, | |
788 | }; | |
789 | ||
790 | const struct bpf_prog_ops kprobe_prog_ops = { | |
791 | }; | |
792 | ||
793 | BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, | |
794 | u64, flags, void *, data, u64, size) | |
795 | { | |
796 | struct pt_regs *regs = *(struct pt_regs **)tp_buff; | |
797 | ||
798 | /* | |
799 | * r1 points to perf tracepoint buffer where first 8 bytes are hidden | |
800 | * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it | |
801 | * from there and call the same bpf_perf_event_output() helper inline. | |
802 | */ | |
803 | return ____bpf_perf_event_output(regs, map, flags, data, size); | |
804 | } | |
805 | ||
806 | static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { | |
807 | .func = bpf_perf_event_output_tp, | |
808 | .gpl_only = true, | |
809 | .ret_type = RET_INTEGER, | |
810 | .arg1_type = ARG_PTR_TO_CTX, | |
811 | .arg2_type = ARG_CONST_MAP_PTR, | |
812 | .arg3_type = ARG_ANYTHING, | |
813 | .arg4_type = ARG_PTR_TO_MEM, | |
814 | .arg5_type = ARG_CONST_SIZE_OR_ZERO, | |
815 | }; | |
816 | ||
817 | BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, | |
818 | u64, flags) | |
819 | { | |
820 | struct pt_regs *regs = *(struct pt_regs **)tp_buff; | |
821 | ||
822 | /* | |
823 | * Same comment as in bpf_perf_event_output_tp(), only that this time | |
824 | * the other helper's function body cannot be inlined due to being | |
825 | * external, thus we need to call raw helper function. | |
826 | */ | |
827 | return bpf_get_stackid((unsigned long) regs, (unsigned long) map, | |
828 | flags, 0, 0); | |
829 | } | |
830 | ||
831 | static const struct bpf_func_proto bpf_get_stackid_proto_tp = { | |
832 | .func = bpf_get_stackid_tp, | |
833 | .gpl_only = true, | |
834 | .ret_type = RET_INTEGER, | |
835 | .arg1_type = ARG_PTR_TO_CTX, | |
836 | .arg2_type = ARG_CONST_MAP_PTR, | |
837 | .arg3_type = ARG_ANYTHING, | |
838 | }; | |
839 | ||
840 | BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size, | |
841 | u64, flags) | |
842 | { | |
843 | struct pt_regs *regs = *(struct pt_regs **)tp_buff; | |
844 | ||
845 | return bpf_get_stack((unsigned long) regs, (unsigned long) buf, | |
846 | (unsigned long) size, flags, 0); | |
847 | } | |
848 | ||
849 | static const struct bpf_func_proto bpf_get_stack_proto_tp = { | |
850 | .func = bpf_get_stack_tp, | |
851 | .gpl_only = true, | |
852 | .ret_type = RET_INTEGER, | |
853 | .arg1_type = ARG_PTR_TO_CTX, | |
854 | .arg2_type = ARG_PTR_TO_UNINIT_MEM, | |
855 | .arg3_type = ARG_CONST_SIZE_OR_ZERO, | |
856 | .arg4_type = ARG_ANYTHING, | |
857 | }; | |
858 | ||
859 | static const struct bpf_func_proto * | |
860 | tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) | |
861 | { | |
862 | switch (func_id) { | |
863 | case BPF_FUNC_perf_event_output: | |
864 | return &bpf_perf_event_output_proto_tp; | |
865 | case BPF_FUNC_get_stackid: | |
866 | return &bpf_get_stackid_proto_tp; | |
867 | case BPF_FUNC_get_stack: | |
868 | return &bpf_get_stack_proto_tp; | |
869 | default: | |
870 | return tracing_func_proto(func_id, prog); | |
871 | } | |
872 | } | |
873 | ||
874 | static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, | |
875 | const struct bpf_prog *prog, | |
876 | struct bpf_insn_access_aux *info) | |
877 | { | |
878 | if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) | |
879 | return false; | |
880 | if (type != BPF_READ) | |
881 | return false; | |
882 | if (off % size != 0) | |
883 | return false; | |
884 | ||
885 | BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); | |
886 | return true; | |
887 | } | |
888 | ||
889 | const struct bpf_verifier_ops tracepoint_verifier_ops = { | |
890 | .get_func_proto = tp_prog_func_proto, | |
891 | .is_valid_access = tp_prog_is_valid_access, | |
892 | }; | |
893 | ||
894 | const struct bpf_prog_ops tracepoint_prog_ops = { | |
895 | }; | |
896 | ||
897 | BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx, | |
898 | struct bpf_perf_event_value *, buf, u32, size) | |
899 | { | |
900 | int err = -EINVAL; | |
901 | ||
902 | if (unlikely(size != sizeof(struct bpf_perf_event_value))) | |
903 | goto clear; | |
904 | err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, | |
905 | &buf->running); | |
906 | if (unlikely(err)) | |
907 | goto clear; | |
908 | return 0; | |
909 | clear: | |
910 | memset(buf, 0, size); | |
911 | return err; | |
912 | } | |
913 | ||
914 | static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { | |
915 | .func = bpf_perf_prog_read_value, | |
916 | .gpl_only = true, | |
917 | .ret_type = RET_INTEGER, | |
918 | .arg1_type = ARG_PTR_TO_CTX, | |
919 | .arg2_type = ARG_PTR_TO_UNINIT_MEM, | |
920 | .arg3_type = ARG_CONST_SIZE, | |
921 | }; | |
922 | ||
923 | static const struct bpf_func_proto * | |
924 | pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) | |
925 | { | |
926 | switch (func_id) { | |
927 | case BPF_FUNC_perf_event_output: | |
928 | return &bpf_perf_event_output_proto_tp; | |
929 | case BPF_FUNC_get_stackid: | |
930 | return &bpf_get_stackid_proto_tp; | |
931 | case BPF_FUNC_get_stack: | |
932 | return &bpf_get_stack_proto_tp; | |
933 | case BPF_FUNC_perf_prog_read_value: | |
934 | return &bpf_perf_prog_read_value_proto; | |
935 | default: | |
936 | return tracing_func_proto(func_id, prog); | |
937 | } | |
938 | } | |
939 | ||
940 | /* | |
941 | * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp | |
942 | * to avoid potential recursive reuse issue when/if tracepoints are added | |
943 | * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. | |
944 | * | |
945 | * Since raw tracepoints run despite bpf_prog_active, support concurrent usage | |
946 | * in normal, irq, and nmi context. | |
947 | */ | |
948 | struct bpf_raw_tp_regs { | |
949 | struct pt_regs regs[3]; | |
950 | }; | |
951 | static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); | |
952 | static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); | |
953 | static struct pt_regs *get_bpf_raw_tp_regs(void) | |
954 | { | |
955 | struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); | |
956 | int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); | |
957 | ||
958 | if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { | |
959 | this_cpu_dec(bpf_raw_tp_nest_level); | |
960 | return ERR_PTR(-EBUSY); | |
961 | } | |
962 | ||
963 | return &tp_regs->regs[nest_level - 1]; | |
964 | } | |
965 | ||
966 | static void put_bpf_raw_tp_regs(void) | |
967 | { | |
968 | this_cpu_dec(bpf_raw_tp_nest_level); | |
969 | } | |
970 | ||
971 | BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, | |
972 | struct bpf_map *, map, u64, flags, void *, data, u64, size) | |
973 | { | |
974 | struct pt_regs *regs = get_bpf_raw_tp_regs(); | |
975 | int ret; | |
976 | ||
977 | if (IS_ERR(regs)) | |
978 | return PTR_ERR(regs); | |
979 | ||
980 | perf_fetch_caller_regs(regs); | |
981 | ret = ____bpf_perf_event_output(regs, map, flags, data, size); | |
982 | ||
983 | put_bpf_raw_tp_regs(); | |
984 | return ret; | |
985 | } | |
986 | ||
987 | static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { | |
988 | .func = bpf_perf_event_output_raw_tp, | |
989 | .gpl_only = true, | |
990 | .ret_type = RET_INTEGER, | |
991 | .arg1_type = ARG_PTR_TO_CTX, | |
992 | .arg2_type = ARG_CONST_MAP_PTR, | |
993 | .arg3_type = ARG_ANYTHING, | |
994 | .arg4_type = ARG_PTR_TO_MEM, | |
995 | .arg5_type = ARG_CONST_SIZE_OR_ZERO, | |
996 | }; | |
997 | ||
998 | BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, | |
999 | struct bpf_map *, map, u64, flags) | |
1000 | { | |
1001 | struct pt_regs *regs = get_bpf_raw_tp_regs(); | |
1002 | int ret; | |
1003 | ||
1004 | if (IS_ERR(regs)) | |
1005 | return PTR_ERR(regs); | |
1006 | ||
1007 | perf_fetch_caller_regs(regs); | |
1008 | /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ | |
1009 | ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, | |
1010 | flags, 0, 0); | |
1011 | put_bpf_raw_tp_regs(); | |
1012 | return ret; | |
1013 | } | |
1014 | ||
1015 | static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { | |
1016 | .func = bpf_get_stackid_raw_tp, | |
1017 | .gpl_only = true, | |
1018 | .ret_type = RET_INTEGER, | |
1019 | .arg1_type = ARG_PTR_TO_CTX, | |
1020 | .arg2_type = ARG_CONST_MAP_PTR, | |
1021 | .arg3_type = ARG_ANYTHING, | |
1022 | }; | |
1023 | ||
1024 | BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, | |
1025 | void *, buf, u32, size, u64, flags) | |
1026 | { | |
1027 | struct pt_regs *regs = get_bpf_raw_tp_regs(); | |
1028 | int ret; | |
1029 | ||
1030 | if (IS_ERR(regs)) | |
1031 | return PTR_ERR(regs); | |
1032 | ||
1033 | perf_fetch_caller_regs(regs); | |
1034 | ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, | |
1035 | (unsigned long) size, flags, 0); | |
1036 | put_bpf_raw_tp_regs(); | |
1037 | return ret; | |
1038 | } | |
1039 | ||
1040 | static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { | |
1041 | .func = bpf_get_stack_raw_tp, | |
1042 | .gpl_only = true, | |
1043 | .ret_type = RET_INTEGER, | |
1044 | .arg1_type = ARG_PTR_TO_CTX, | |
1045 | .arg2_type = ARG_PTR_TO_MEM, | |
1046 | .arg3_type = ARG_CONST_SIZE_OR_ZERO, | |
1047 | .arg4_type = ARG_ANYTHING, | |
1048 | }; | |
1049 | ||
1050 | static const struct bpf_func_proto * | |
1051 | raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) | |
1052 | { | |
1053 | switch (func_id) { | |
1054 | case BPF_FUNC_perf_event_output: | |
1055 | return &bpf_perf_event_output_proto_raw_tp; | |
1056 | case BPF_FUNC_get_stackid: | |
1057 | return &bpf_get_stackid_proto_raw_tp; | |
1058 | case BPF_FUNC_get_stack: | |
1059 | return &bpf_get_stack_proto_raw_tp; | |
1060 | default: | |
1061 | return tracing_func_proto(func_id, prog); | |
1062 | } | |
1063 | } | |
1064 | ||
1065 | static bool raw_tp_prog_is_valid_access(int off, int size, | |
1066 | enum bpf_access_type type, | |
1067 | const struct bpf_prog *prog, | |
1068 | struct bpf_insn_access_aux *info) | |
1069 | { | |
1070 | /* largest tracepoint in the kernel has 12 args */ | |
1071 | if (off < 0 || off >= sizeof(__u64) * 12) | |
1072 | return false; | |
1073 | if (type != BPF_READ) | |
1074 | return false; | |
1075 | if (off % size != 0) | |
1076 | return false; | |
1077 | return btf_ctx_access(off, size, type, prog, info); | |
1078 | } | |
1079 | ||
1080 | const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { | |
1081 | .get_func_proto = raw_tp_prog_func_proto, | |
1082 | .is_valid_access = raw_tp_prog_is_valid_access, | |
1083 | }; | |
1084 | ||
1085 | const struct bpf_prog_ops raw_tracepoint_prog_ops = { | |
1086 | }; | |
1087 | ||
1088 | static bool raw_tp_writable_prog_is_valid_access(int off, int size, | |
1089 | enum bpf_access_type type, | |
1090 | const struct bpf_prog *prog, | |
1091 | struct bpf_insn_access_aux *info) | |
1092 | { | |
1093 | if (off == 0) { | |
1094 | if (size != sizeof(u64) || type != BPF_READ) | |
1095 | return false; | |
1096 | info->reg_type = PTR_TO_TP_BUFFER; | |
1097 | } | |
1098 | return raw_tp_prog_is_valid_access(off, size, type, prog, info); | |
1099 | } | |
1100 | ||
1101 | const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { | |
1102 | .get_func_proto = raw_tp_prog_func_proto, | |
1103 | .is_valid_access = raw_tp_writable_prog_is_valid_access, | |
1104 | }; | |
1105 | ||
1106 | const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { | |
1107 | }; | |
1108 | ||
1109 | static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, | |
1110 | const struct bpf_prog *prog, | |
1111 | struct bpf_insn_access_aux *info) | |
1112 | { | |
1113 | const int size_u64 = sizeof(u64); | |
1114 | ||
1115 | if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) | |
1116 | return false; | |
1117 | if (type != BPF_READ) | |
1118 | return false; | |
1119 | if (off % size != 0) { | |
1120 | if (sizeof(unsigned long) != 4) | |
1121 | return false; | |
1122 | if (size != 8) | |
1123 | return false; | |
1124 | if (off % size != 4) | |
1125 | return false; | |
1126 | } | |
1127 | ||
1128 | switch (off) { | |
1129 | case bpf_ctx_range(struct bpf_perf_event_data, sample_period): | |
1130 | bpf_ctx_record_field_size(info, size_u64); | |
1131 | if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) | |
1132 | return false; | |
1133 | break; | |
1134 | case bpf_ctx_range(struct bpf_perf_event_data, addr): | |
1135 | bpf_ctx_record_field_size(info, size_u64); | |
1136 | if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) | |
1137 | return false; | |
1138 | break; | |
1139 | default: | |
1140 | if (size != sizeof(long)) | |
1141 | return false; | |
1142 | } | |
1143 | ||
1144 | return true; | |
1145 | } | |
1146 | ||
1147 | static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, | |
1148 | const struct bpf_insn *si, | |
1149 | struct bpf_insn *insn_buf, | |
1150 | struct bpf_prog *prog, u32 *target_size) | |
1151 | { | |
1152 | struct bpf_insn *insn = insn_buf; | |
1153 | ||
1154 | switch (si->off) { | |
1155 | case offsetof(struct bpf_perf_event_data, sample_period): | |
1156 | *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, | |
1157 | data), si->dst_reg, si->src_reg, | |
1158 | offsetof(struct bpf_perf_event_data_kern, data)); | |
1159 | *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, | |
1160 | bpf_target_off(struct perf_sample_data, period, 8, | |
1161 | target_size)); | |
1162 | break; | |
1163 | case offsetof(struct bpf_perf_event_data, addr): | |
1164 | *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, | |
1165 | data), si->dst_reg, si->src_reg, | |
1166 | offsetof(struct bpf_perf_event_data_kern, data)); | |
1167 | *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, | |
1168 | bpf_target_off(struct perf_sample_data, addr, 8, | |
1169 | target_size)); | |
1170 | break; | |
1171 | default: | |
1172 | *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, | |
1173 | regs), si->dst_reg, si->src_reg, | |
1174 | offsetof(struct bpf_perf_event_data_kern, regs)); | |
1175 | *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, | |
1176 | si->off); | |
1177 | break; | |
1178 | } | |
1179 | ||
1180 | return insn - insn_buf; | |
1181 | } | |
1182 | ||
1183 | const struct bpf_verifier_ops perf_event_verifier_ops = { | |
1184 | .get_func_proto = pe_prog_func_proto, | |
1185 | .is_valid_access = pe_prog_is_valid_access, | |
1186 | .convert_ctx_access = pe_prog_convert_ctx_access, | |
1187 | }; | |
1188 | ||
1189 | const struct bpf_prog_ops perf_event_prog_ops = { | |
1190 | }; | |
1191 | ||
1192 | static DEFINE_MUTEX(bpf_event_mutex); | |
1193 | ||
1194 | #define BPF_TRACE_MAX_PROGS 64 | |
1195 | ||
1196 | int perf_event_attach_bpf_prog(struct perf_event *event, | |
1197 | struct bpf_prog *prog) | |
1198 | { | |
1199 | struct bpf_prog_array *old_array; | |
1200 | struct bpf_prog_array *new_array; | |
1201 | int ret = -EEXIST; | |
1202 | ||
1203 | /* | |
1204 | * Kprobe override only works if they are on the function entry, | |
1205 | * and only if they are on the opt-in list. | |
1206 | */ | |
1207 | if (prog->kprobe_override && | |
1208 | (!trace_kprobe_on_func_entry(event->tp_event) || | |
1209 | !trace_kprobe_error_injectable(event->tp_event))) | |
1210 | return -EINVAL; | |
1211 | ||
1212 | mutex_lock(&bpf_event_mutex); | |
1213 | ||
1214 | if (event->prog) | |
1215 | goto unlock; | |
1216 | ||
1217 | old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); | |
1218 | if (old_array && | |
1219 | bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { | |
1220 | ret = -E2BIG; | |
1221 | goto unlock; | |
1222 | } | |
1223 | ||
1224 | ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); | |
1225 | if (ret < 0) | |
1226 | goto unlock; | |
1227 | ||
1228 | /* set the new array to event->tp_event and set event->prog */ | |
1229 | event->prog = prog; | |
1230 | rcu_assign_pointer(event->tp_event->prog_array, new_array); | |
1231 | bpf_prog_array_free(old_array); | |
1232 | ||
1233 | unlock: | |
1234 | mutex_unlock(&bpf_event_mutex); | |
1235 | return ret; | |
1236 | } | |
1237 | ||
1238 | void perf_event_detach_bpf_prog(struct perf_event *event) | |
1239 | { | |
1240 | struct bpf_prog_array *old_array; | |
1241 | struct bpf_prog_array *new_array; | |
1242 | int ret; | |
1243 | ||
1244 | mutex_lock(&bpf_event_mutex); | |
1245 | ||
1246 | if (!event->prog) | |
1247 | goto unlock; | |
1248 | ||
1249 | old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); | |
1250 | ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); | |
1251 | if (ret == -ENOENT) | |
1252 | goto unlock; | |
1253 | if (ret < 0) { | |
1254 | bpf_prog_array_delete_safe(old_array, event->prog); | |
1255 | } else { | |
1256 | rcu_assign_pointer(event->tp_event->prog_array, new_array); | |
1257 | bpf_prog_array_free(old_array); | |
1258 | } | |
1259 | ||
1260 | bpf_prog_put(event->prog); | |
1261 | event->prog = NULL; | |
1262 | ||
1263 | unlock: | |
1264 | mutex_unlock(&bpf_event_mutex); | |
1265 | } | |
1266 | ||
1267 | int perf_event_query_prog_array(struct perf_event *event, void __user *info) | |
1268 | { | |
1269 | struct perf_event_query_bpf __user *uquery = info; | |
1270 | struct perf_event_query_bpf query = {}; | |
1271 | struct bpf_prog_array *progs; | |
1272 | u32 *ids, prog_cnt, ids_len; | |
1273 | int ret; | |
1274 | ||
1275 | if (!capable(CAP_SYS_ADMIN)) | |
1276 | return -EPERM; | |
1277 | if (event->attr.type != PERF_TYPE_TRACEPOINT) | |
1278 | return -EINVAL; | |
1279 | if (copy_from_user(&query, uquery, sizeof(query))) | |
1280 | return -EFAULT; | |
1281 | ||
1282 | ids_len = query.ids_len; | |
1283 | if (ids_len > BPF_TRACE_MAX_PROGS) | |
1284 | return -E2BIG; | |
1285 | ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); | |
1286 | if (!ids) | |
1287 | return -ENOMEM; | |
1288 | /* | |
1289 | * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which | |
1290 | * is required when user only wants to check for uquery->prog_cnt. | |
1291 | * There is no need to check for it since the case is handled | |
1292 | * gracefully in bpf_prog_array_copy_info. | |
1293 | */ | |
1294 | ||
1295 | mutex_lock(&bpf_event_mutex); | |
1296 | progs = bpf_event_rcu_dereference(event->tp_event->prog_array); | |
1297 | ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt); | |
1298 | mutex_unlock(&bpf_event_mutex); | |
1299 | ||
1300 | if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || | |
1301 | copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) | |
1302 | ret = -EFAULT; | |
1303 | ||
1304 | kfree(ids); | |
1305 | return ret; | |
1306 | } | |
1307 | ||
1308 | extern struct bpf_raw_event_map __start__bpf_raw_tp[]; | |
1309 | extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; | |
1310 | ||
1311 | struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) | |
1312 | { | |
1313 | struct bpf_raw_event_map *btp = __start__bpf_raw_tp; | |
1314 | ||
1315 | for (; btp < __stop__bpf_raw_tp; btp++) { | |
1316 | if (!strcmp(btp->tp->name, name)) | |
1317 | return btp; | |
1318 | } | |
1319 | ||
1320 | return bpf_get_raw_tracepoint_module(name); | |
1321 | } | |
1322 | ||
1323 | void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) | |
1324 | { | |
1325 | struct module *mod = __module_address((unsigned long)btp); | |
1326 | ||
1327 | if (mod) | |
1328 | module_put(mod); | |
1329 | } | |
1330 | ||
1331 | static __always_inline | |
1332 | void __bpf_trace_run(struct bpf_prog *prog, u64 *args) | |
1333 | { | |
1334 | rcu_read_lock(); | |
1335 | preempt_disable(); | |
1336 | (void) BPF_PROG_RUN(prog, args); | |
1337 | preempt_enable(); | |
1338 | rcu_read_unlock(); | |
1339 | } | |
1340 | ||
1341 | #define UNPACK(...) __VA_ARGS__ | |
1342 | #define REPEAT_1(FN, DL, X, ...) FN(X) | |
1343 | #define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) | |
1344 | #define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) | |
1345 | #define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) | |
1346 | #define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) | |
1347 | #define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) | |
1348 | #define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) | |
1349 | #define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) | |
1350 | #define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) | |
1351 | #define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) | |
1352 | #define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) | |
1353 | #define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) | |
1354 | #define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) | |
1355 | ||
1356 | #define SARG(X) u64 arg##X | |
1357 | #define COPY(X) args[X] = arg##X | |
1358 | ||
1359 | #define __DL_COM (,) | |
1360 | #define __DL_SEM (;) | |
1361 | ||
1362 | #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 | |
1363 | ||
1364 | #define BPF_TRACE_DEFN_x(x) \ | |
1365 | void bpf_trace_run##x(struct bpf_prog *prog, \ | |
1366 | REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ | |
1367 | { \ | |
1368 | u64 args[x]; \ | |
1369 | REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ | |
1370 | __bpf_trace_run(prog, args); \ | |
1371 | } \ | |
1372 | EXPORT_SYMBOL_GPL(bpf_trace_run##x) | |
1373 | BPF_TRACE_DEFN_x(1); | |
1374 | BPF_TRACE_DEFN_x(2); | |
1375 | BPF_TRACE_DEFN_x(3); | |
1376 | BPF_TRACE_DEFN_x(4); | |
1377 | BPF_TRACE_DEFN_x(5); | |
1378 | BPF_TRACE_DEFN_x(6); | |
1379 | BPF_TRACE_DEFN_x(7); | |
1380 | BPF_TRACE_DEFN_x(8); | |
1381 | BPF_TRACE_DEFN_x(9); | |
1382 | BPF_TRACE_DEFN_x(10); | |
1383 | BPF_TRACE_DEFN_x(11); | |
1384 | BPF_TRACE_DEFN_x(12); | |
1385 | ||
1386 | static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) | |
1387 | { | |
1388 | struct tracepoint *tp = btp->tp; | |
1389 | ||
1390 | /* | |
1391 | * check that program doesn't access arguments beyond what's | |
1392 | * available in this tracepoint | |
1393 | */ | |
1394 | if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) | |
1395 | return -EINVAL; | |
1396 | ||
1397 | if (prog->aux->max_tp_access > btp->writable_size) | |
1398 | return -EINVAL; | |
1399 | ||
1400 | return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); | |
1401 | } | |
1402 | ||
1403 | int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) | |
1404 | { | |
1405 | return __bpf_probe_register(btp, prog); | |
1406 | } | |
1407 | ||
1408 | int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) | |
1409 | { | |
1410 | return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); | |
1411 | } | |
1412 | ||
1413 | int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, | |
1414 | u32 *fd_type, const char **buf, | |
1415 | u64 *probe_offset, u64 *probe_addr) | |
1416 | { | |
1417 | bool is_tracepoint, is_syscall_tp; | |
1418 | struct bpf_prog *prog; | |
1419 | int flags, err = 0; | |
1420 | ||
1421 | prog = event->prog; | |
1422 | if (!prog) | |
1423 | return -ENOENT; | |
1424 | ||
1425 | /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */ | |
1426 | if (prog->type == BPF_PROG_TYPE_PERF_EVENT) | |
1427 | return -EOPNOTSUPP; | |
1428 | ||
1429 | *prog_id = prog->aux->id; | |
1430 | flags = event->tp_event->flags; | |
1431 | is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT; | |
1432 | is_syscall_tp = is_syscall_trace_event(event->tp_event); | |
1433 | ||
1434 | if (is_tracepoint || is_syscall_tp) { | |
1435 | *buf = is_tracepoint ? event->tp_event->tp->name | |
1436 | : event->tp_event->name; | |
1437 | *fd_type = BPF_FD_TYPE_TRACEPOINT; | |
1438 | *probe_offset = 0x0; | |
1439 | *probe_addr = 0x0; | |
1440 | } else { | |
1441 | /* kprobe/uprobe */ | |
1442 | err = -EOPNOTSUPP; | |
1443 | #ifdef CONFIG_KPROBE_EVENTS | |
1444 | if (flags & TRACE_EVENT_FL_KPROBE) | |
1445 | err = bpf_get_kprobe_info(event, fd_type, buf, | |
1446 | probe_offset, probe_addr, | |
1447 | event->attr.type == PERF_TYPE_TRACEPOINT); | |
1448 | #endif | |
1449 | #ifdef CONFIG_UPROBE_EVENTS | |
1450 | if (flags & TRACE_EVENT_FL_UPROBE) | |
1451 | err = bpf_get_uprobe_info(event, fd_type, buf, | |
1452 | probe_offset, | |
1453 | event->attr.type == PERF_TYPE_TRACEPOINT); | |
1454 | #endif | |
1455 | } | |
1456 | ||
1457 | return err; | |
1458 | } | |
1459 | ||
1460 | static int __init send_signal_irq_work_init(void) | |
1461 | { | |
1462 | int cpu; | |
1463 | struct send_signal_irq_work *work; | |
1464 | ||
1465 | for_each_possible_cpu(cpu) { | |
1466 | work = per_cpu_ptr(&send_signal_work, cpu); | |
1467 | init_irq_work(&work->irq_work, do_bpf_send_signal); | |
1468 | } | |
1469 | return 0; | |
1470 | } | |
1471 | ||
1472 | subsys_initcall(send_signal_irq_work_init); | |
1473 | ||
1474 | #ifdef CONFIG_MODULES | |
1475 | static int bpf_event_notify(struct notifier_block *nb, unsigned long op, | |
1476 | void *module) | |
1477 | { | |
1478 | struct bpf_trace_module *btm, *tmp; | |
1479 | struct module *mod = module; | |
1480 | ||
1481 | if (mod->num_bpf_raw_events == 0 || | |
1482 | (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) | |
1483 | return 0; | |
1484 | ||
1485 | mutex_lock(&bpf_module_mutex); | |
1486 | ||
1487 | switch (op) { | |
1488 | case MODULE_STATE_COMING: | |
1489 | btm = kzalloc(sizeof(*btm), GFP_KERNEL); | |
1490 | if (btm) { | |
1491 | btm->module = module; | |
1492 | list_add(&btm->list, &bpf_trace_modules); | |
1493 | } | |
1494 | break; | |
1495 | case MODULE_STATE_GOING: | |
1496 | list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) { | |
1497 | if (btm->module == module) { | |
1498 | list_del(&btm->list); | |
1499 | kfree(btm); | |
1500 | break; | |
1501 | } | |
1502 | } | |
1503 | break; | |
1504 | } | |
1505 | ||
1506 | mutex_unlock(&bpf_module_mutex); | |
1507 | ||
1508 | return 0; | |
1509 | } | |
1510 | ||
1511 | static struct notifier_block bpf_module_nb = { | |
1512 | .notifier_call = bpf_event_notify, | |
1513 | }; | |
1514 | ||
1515 | static int __init bpf_event_init(void) | |
1516 | { | |
1517 | register_module_notifier(&bpf_module_nb); | |
1518 | return 0; | |
1519 | } | |
1520 | ||
1521 | fs_initcall(bpf_event_init); | |
1522 | #endif /* CONFIG_MODULES */ |