~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/kernel/trace/bpf_trace.c

Version: ~ [ linux-4.14 ] ~ [ linux-4.13.12 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.61 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.97 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.46 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.80 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.50 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.95 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com
  2  * Copyright (c) 2016 Facebook
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of version 2 of the GNU General Public
  6  * License as published by the Free Software Foundation.
  7  */
  8 #include <linux/kernel.h>
  9 #include <linux/types.h>
 10 #include <linux/slab.h>
 11 #include <linux/bpf.h>
 12 #include <linux/bpf_perf_event.h>
 13 #include <linux/filter.h>
 14 #include <linux/uaccess.h>
 15 #include <linux/ctype.h>
 16 #include "trace.h"
 17 
 18 /**
 19  * trace_call_bpf - invoke BPF program
 20  * @prog: BPF program
 21  * @ctx: opaque context pointer
 22  *
 23  * kprobe handlers execute BPF programs via this helper.
 24  * Can be used from static tracepoints in the future.
 25  *
 26  * Return: BPF programs always return an integer which is interpreted by
 27  * kprobe handler as:
 28  * 0 - return from kprobe (event is filtered out)
 29  * 1 - store kprobe event into ring buffer
 30  * Other values are reserved and currently alias to 1
 31  */
 32 unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
 33 {
 34         unsigned int ret;
 35 
 36         if (in_nmi()) /* not supported yet */
 37                 return 1;
 38 
 39         preempt_disable();
 40 
 41         if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
 42                 /*
 43                  * since some bpf program is already running on this cpu,
 44                  * don't call into another bpf program (same or different)
 45                  * and don't send kprobe event into ring-buffer,
 46                  * so return zero here
 47                  */
 48                 ret = 0;
 49                 goto out;
 50         }
 51 
 52         rcu_read_lock();
 53         ret = BPF_PROG_RUN(prog, ctx);
 54         rcu_read_unlock();
 55 
 56  out:
 57         __this_cpu_dec(bpf_prog_active);
 58         preempt_enable();
 59 
 60         return ret;
 61 }
 62 EXPORT_SYMBOL_GPL(trace_call_bpf);
 63 
 64 BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr)
 65 {
 66         int ret;
 67 
 68         ret = probe_kernel_read(dst, unsafe_ptr, size);
 69         if (unlikely(ret < 0))
 70                 memset(dst, 0, size);
 71 
 72         return ret;
 73 }
 74 
 75 static const struct bpf_func_proto bpf_probe_read_proto = {
 76         .func           = bpf_probe_read,
 77         .gpl_only       = true,
 78         .ret_type       = RET_INTEGER,
 79         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 80         .arg2_type      = ARG_CONST_SIZE,
 81         .arg3_type      = ARG_ANYTHING,
 82 };
 83 
 84 BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
 85            u32, size)
 86 {
 87         /*
 88          * Ensure we're in user context which is safe for the helper to
 89          * run. This helper has no business in a kthread.
 90          *
 91          * access_ok() should prevent writing to non-user memory, but in
 92          * some situations (nommu, temporary switch, etc) access_ok() does
 93          * not provide enough validation, hence the check on KERNEL_DS.
 94          */
 95 
 96         if (unlikely(in_interrupt() ||
 97                      current->flags & (PF_KTHREAD | PF_EXITING)))
 98                 return -EPERM;
 99         if (unlikely(uaccess_kernel()))
100                 return -EPERM;
101         if (!access_ok(VERIFY_WRITE, unsafe_ptr, size))
102                 return -EPERM;
103 
104         return probe_kernel_write(unsafe_ptr, src, size);
105 }
106 
107 static const struct bpf_func_proto bpf_probe_write_user_proto = {
108         .func           = bpf_probe_write_user,
109         .gpl_only       = true,
110         .ret_type       = RET_INTEGER,
111         .arg1_type      = ARG_ANYTHING,
112         .arg2_type      = ARG_PTR_TO_MEM,
113         .arg3_type      = ARG_CONST_SIZE,
114 };
115 
116 static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
117 {
118         pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",
119                             current->comm, task_pid_nr(current));
120 
121         return &bpf_probe_write_user_proto;
122 }
123 
124 /*
125  * Only limited trace_printk() conversion specifiers allowed:
126  * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s
127  */
128 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
129            u64, arg2, u64, arg3)
130 {
131         bool str_seen = false;
132         int mod[3] = {};
133         int fmt_cnt = 0;
134         u64 unsafe_addr;
135         char buf[64];
136         int i;
137 
138         /*
139          * bpf_check()->check_func_arg()->check_stack_boundary()
140          * guarantees that fmt points to bpf program stack,
141          * fmt_size bytes of it were initialized and fmt_size > 0
142          */
143         if (fmt[--fmt_size] != 0)
144                 return -EINVAL;
145 
146         /* check format string for allowed specifiers */
147         for (i = 0; i < fmt_size; i++) {
148                 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))
149                         return -EINVAL;
150 
151                 if (fmt[i] != '%')
152                         continue;
153 
154                 if (fmt_cnt >= 3)
155                         return -EINVAL;
156 
157                 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
158                 i++;
159                 if (fmt[i] == 'l') {
160                         mod[fmt_cnt]++;
161                         i++;
162                 } else if (fmt[i] == 'p' || fmt[i] == 's') {
163                         mod[fmt_cnt]++;
164                         i++;
165                         if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0)
166                                 return -EINVAL;
167                         fmt_cnt++;
168                         if (fmt[i - 1] == 's') {
169                                 if (str_seen)
170                                         /* allow only one '%s' per fmt string */
171                                         return -EINVAL;
172                                 str_seen = true;
173 
174                                 switch (fmt_cnt) {
175                                 case 1:
176                                         unsafe_addr = arg1;
177                                         arg1 = (long) buf;
178                                         break;
179                                 case 2:
180                                         unsafe_addr = arg2;
181                                         arg2 = (long) buf;
182                                         break;
183                                 case 3:
184                                         unsafe_addr = arg3;
185                                         arg3 = (long) buf;
186                                         break;
187                                 }
188                                 buf[0] = 0;
189                                 strncpy_from_unsafe(buf,
190                                                     (void *) (long) unsafe_addr,
191                                                     sizeof(buf));
192                         }
193                         continue;
194                 }
195 
196                 if (fmt[i] == 'l') {
197                         mod[fmt_cnt]++;
198                         i++;
199                 }
200 
201                 if (fmt[i] != 'i' && fmt[i] != 'd' &&
202                     fmt[i] != 'u' && fmt[i] != 'x')
203                         return -EINVAL;
204                 fmt_cnt++;
205         }
206 
207 /* Horrid workaround for getting va_list handling working with different
208  * argument type combinations generically for 32 and 64 bit archs.
209  */
210 #define __BPF_TP_EMIT() __BPF_ARG3_TP()
211 #define __BPF_TP(...)                                                   \
212         __trace_printk(1 /* Fake ip will not be printed. */,            \
213                        fmt, ##__VA_ARGS__)
214 
215 #define __BPF_ARG1_TP(...)                                              \
216         ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64))        \
217           ? __BPF_TP(arg1, ##__VA_ARGS__)                               \
218           : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32))    \
219               ? __BPF_TP((long)arg1, ##__VA_ARGS__)                     \
220               : __BPF_TP((u32)arg1, ##__VA_ARGS__)))
221 
222 #define __BPF_ARG2_TP(...)                                              \
223         ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64))        \
224           ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__)                          \
225           : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32))    \
226               ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__)                \
227               : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__)))
228 
229 #define __BPF_ARG3_TP(...)                                              \
230         ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64))        \
231           ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__)                          \
232           : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32))    \
233               ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__)                \
234               : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__)))
235 
236         return __BPF_TP_EMIT();
237 }
238 
239 static const struct bpf_func_proto bpf_trace_printk_proto = {
240         .func           = bpf_trace_printk,
241         .gpl_only       = true,
242         .ret_type       = RET_INTEGER,
243         .arg1_type      = ARG_PTR_TO_MEM,
244         .arg2_type      = ARG_CONST_SIZE,
245 };
246 
247 const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
248 {
249         /*
250          * this program might be calling bpf_trace_printk,
251          * so allocate per-cpu printk buffers
252          */
253         trace_printk_init_buffers();
254 
255         return &bpf_trace_printk_proto;
256 }
257 
258 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
259 {
260         struct bpf_array *array = container_of(map, struct bpf_array, map);
261         unsigned int cpu = smp_processor_id();
262         u64 index = flags & BPF_F_INDEX_MASK;
263         struct bpf_event_entry *ee;
264         u64 value = 0;
265         int err;
266 
267         if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
268                 return -EINVAL;
269         if (index == BPF_F_CURRENT_CPU)
270                 index = cpu;
271         if (unlikely(index >= array->map.max_entries))
272                 return -E2BIG;
273 
274         ee = READ_ONCE(array->ptrs[index]);
275         if (!ee)
276                 return -ENOENT;
277 
278         err = perf_event_read_local(ee->event, &value);
279         /*
280          * this api is ugly since we miss [-22..-2] range of valid
281          * counter values, but that's uapi
282          */
283         if (err)
284                 return err;
285         return value;
286 }
287 
288 static const struct bpf_func_proto bpf_perf_event_read_proto = {
289         .func           = bpf_perf_event_read,
290         .gpl_only       = true,
291         .ret_type       = RET_INTEGER,
292         .arg1_type      = ARG_CONST_MAP_PTR,
293         .arg2_type      = ARG_ANYTHING,
294 };
295 
296 static DEFINE_PER_CPU(struct perf_sample_data, bpf_sd);
297 
298 static __always_inline u64
299 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
300                         u64 flags, struct perf_raw_record *raw)
301 {
302         struct bpf_array *array = container_of(map, struct bpf_array, map);
303         struct perf_sample_data *sd = this_cpu_ptr(&bpf_sd);
304         unsigned int cpu = smp_processor_id();
305         u64 index = flags & BPF_F_INDEX_MASK;
306         struct bpf_event_entry *ee;
307         struct perf_event *event;
308 
309         if (index == BPF_F_CURRENT_CPU)
310                 index = cpu;
311         if (unlikely(index >= array->map.max_entries))
312                 return -E2BIG;
313 
314         ee = READ_ONCE(array->ptrs[index]);
315         if (!ee)
316                 return -ENOENT;
317 
318         event = ee->event;
319         if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
320                      event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
321                 return -EINVAL;
322 
323         if (unlikely(event->oncpu != cpu))
324                 return -EOPNOTSUPP;
325 
326         perf_sample_data_init(sd, 0, 0);
327         sd->raw = raw;
328         perf_event_output(event, sd, regs);
329         return 0;
330 }
331 
332 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
333            u64, flags, void *, data, u64, size)
334 {
335         struct perf_raw_record raw = {
336                 .frag = {
337                         .size = size,
338                         .data = data,
339                 },
340         };
341 
342         if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
343                 return -EINVAL;
344 
345         return __bpf_perf_event_output(regs, map, flags, &raw);
346 }
347 
348 static const struct bpf_func_proto bpf_perf_event_output_proto = {
349         .func           = bpf_perf_event_output,
350         .gpl_only       = true,
351         .ret_type       = RET_INTEGER,
352         .arg1_type      = ARG_PTR_TO_CTX,
353         .arg2_type      = ARG_CONST_MAP_PTR,
354         .arg3_type      = ARG_ANYTHING,
355         .arg4_type      = ARG_PTR_TO_MEM,
356         .arg5_type      = ARG_CONST_SIZE,
357 };
358 
359 static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs);
360 
361 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
362                      void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
363 {
364         struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs);
365         struct perf_raw_frag frag = {
366                 .copy           = ctx_copy,
367                 .size           = ctx_size,
368                 .data           = ctx,
369         };
370         struct perf_raw_record raw = {
371                 .frag = {
372                         {
373                                 .next   = ctx_size ? &frag : NULL,
374                         },
375                         .size   = meta_size,
376                         .data   = meta,
377                 },
378         };
379 
380         perf_fetch_caller_regs(regs);
381 
382         return __bpf_perf_event_output(regs, map, flags, &raw);
383 }
384 
385 BPF_CALL_0(bpf_get_current_task)
386 {
387         return (long) current;
388 }
389 
390 static const struct bpf_func_proto bpf_get_current_task_proto = {
391         .func           = bpf_get_current_task,
392         .gpl_only       = true,
393         .ret_type       = RET_INTEGER,
394 };
395 
396 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx)
397 {
398         struct bpf_array *array = container_of(map, struct bpf_array, map);
399         struct cgroup *cgrp;
400 
401         if (unlikely(in_interrupt()))
402                 return -EINVAL;
403         if (unlikely(idx >= array->map.max_entries))
404                 return -E2BIG;
405 
406         cgrp = READ_ONCE(array->ptrs[idx]);
407         if (unlikely(!cgrp))
408                 return -EAGAIN;
409 
410         return task_under_cgroup_hierarchy(current, cgrp);
411 }
412 
413 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = {
414         .func           = bpf_current_task_under_cgroup,
415         .gpl_only       = false,
416         .ret_type       = RET_INTEGER,
417         .arg1_type      = ARG_CONST_MAP_PTR,
418         .arg2_type      = ARG_ANYTHING,
419 };
420 
421 BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size,
422            const void *, unsafe_ptr)
423 {
424         int ret;
425 
426         /*
427          * The strncpy_from_unsafe() call will likely not fill the entire
428          * buffer, but that's okay in this circumstance as we're probing
429          * arbitrary memory anyway similar to bpf_probe_read() and might
430          * as well probe the stack. Thus, memory is explicitly cleared
431          * only in error case, so that improper users ignoring return
432          * code altogether don't copy garbage; otherwise length of string
433          * is returned that can be used for bpf_perf_event_output() et al.
434          */
435         ret = strncpy_from_unsafe(dst, unsafe_ptr, size);
436         if (unlikely(ret < 0))
437                 memset(dst, 0, size);
438 
439         return ret;
440 }
441 
442 static const struct bpf_func_proto bpf_probe_read_str_proto = {
443         .func           = bpf_probe_read_str,
444         .gpl_only       = true,
445         .ret_type       = RET_INTEGER,
446         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
447         .arg2_type      = ARG_CONST_SIZE,
448         .arg3_type      = ARG_ANYTHING,
449 };
450 
451 static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)
452 {
453         switch (func_id) {
454         case BPF_FUNC_map_lookup_elem:
455                 return &bpf_map_lookup_elem_proto;
456         case BPF_FUNC_map_update_elem:
457                 return &bpf_map_update_elem_proto;
458         case BPF_FUNC_map_delete_elem:
459                 return &bpf_map_delete_elem_proto;
460         case BPF_FUNC_probe_read:
461                 return &bpf_probe_read_proto;
462         case BPF_FUNC_ktime_get_ns:
463                 return &bpf_ktime_get_ns_proto;
464         case BPF_FUNC_tail_call:
465                 return &bpf_tail_call_proto;
466         case BPF_FUNC_get_current_pid_tgid:
467                 return &bpf_get_current_pid_tgid_proto;
468         case BPF_FUNC_get_current_task:
469                 return &bpf_get_current_task_proto;
470         case BPF_FUNC_get_current_uid_gid:
471                 return &bpf_get_current_uid_gid_proto;
472         case BPF_FUNC_get_current_comm:
473                 return &bpf_get_current_comm_proto;
474         case BPF_FUNC_trace_printk:
475                 return bpf_get_trace_printk_proto();
476         case BPF_FUNC_get_smp_processor_id:
477                 return &bpf_get_smp_processor_id_proto;
478         case BPF_FUNC_get_numa_node_id:
479                 return &bpf_get_numa_node_id_proto;
480         case BPF_FUNC_perf_event_read:
481                 return &bpf_perf_event_read_proto;
482         case BPF_FUNC_probe_write_user:
483                 return bpf_get_probe_write_proto();
484         case BPF_FUNC_current_task_under_cgroup:
485                 return &bpf_current_task_under_cgroup_proto;
486         case BPF_FUNC_get_prandom_u32:
487                 return &bpf_get_prandom_u32_proto;
488         case BPF_FUNC_probe_read_str:
489                 return &bpf_probe_read_str_proto;
490         default:
491                 return NULL;
492         }
493 }
494 
495 static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
496 {
497         switch (func_id) {
498         case BPF_FUNC_perf_event_output:
499                 return &bpf_perf_event_output_proto;
500         case BPF_FUNC_get_stackid:
501                 return &bpf_get_stackid_proto;
502         default:
503                 return tracing_func_proto(func_id);
504         }
505 }
506 
507 /* bpf+kprobe programs can access fields of 'struct pt_regs' */
508 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
509                                         struct bpf_insn_access_aux *info)
510 {
511         if (off < 0 || off >= sizeof(struct pt_regs))
512                 return false;
513         if (type != BPF_READ)
514                 return false;
515         if (off % size != 0)
516                 return false;
517         /*
518          * Assertion for 32 bit to make sure last 8 byte access
519          * (BPF_DW) to the last 4 byte member is disallowed.
520          */
521         if (off + size > sizeof(struct pt_regs))
522                 return false;
523 
524         return true;
525 }
526 
527 const struct bpf_verifier_ops kprobe_prog_ops = {
528         .get_func_proto  = kprobe_prog_func_proto,
529         .is_valid_access = kprobe_prog_is_valid_access,
530 };
531 
532 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
533            u64, flags, void *, data, u64, size)
534 {
535         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
536 
537         /*
538          * r1 points to perf tracepoint buffer where first 8 bytes are hidden
539          * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it
540          * from there and call the same bpf_perf_event_output() helper inline.
541          */
542         return ____bpf_perf_event_output(regs, map, flags, data, size);
543 }
544 
545 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
546         .func           = bpf_perf_event_output_tp,
547         .gpl_only       = true,
548         .ret_type       = RET_INTEGER,
549         .arg1_type      = ARG_PTR_TO_CTX,
550         .arg2_type      = ARG_CONST_MAP_PTR,
551         .arg3_type      = ARG_ANYTHING,
552         .arg4_type      = ARG_PTR_TO_MEM,
553         .arg5_type      = ARG_CONST_SIZE,
554 };
555 
556 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
557            u64, flags)
558 {
559         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
560 
561         /*
562          * Same comment as in bpf_perf_event_output_tp(), only that this time
563          * the other helper's function body cannot be inlined due to being
564          * external, thus we need to call raw helper function.
565          */
566         return bpf_get_stackid((unsigned long) regs, (unsigned long) map,
567                                flags, 0, 0);
568 }
569 
570 static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
571         .func           = bpf_get_stackid_tp,
572         .gpl_only       = true,
573         .ret_type       = RET_INTEGER,
574         .arg1_type      = ARG_PTR_TO_CTX,
575         .arg2_type      = ARG_CONST_MAP_PTR,
576         .arg3_type      = ARG_ANYTHING,
577 };
578 
579 static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
580 {
581         switch (func_id) {
582         case BPF_FUNC_perf_event_output:
583                 return &bpf_perf_event_output_proto_tp;
584         case BPF_FUNC_get_stackid:
585                 return &bpf_get_stackid_proto_tp;
586         default:
587                 return tracing_func_proto(func_id);
588         }
589 }
590 
591 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,
592                                     struct bpf_insn_access_aux *info)
593 {
594         if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
595                 return false;
596         if (type != BPF_READ)
597                 return false;
598         if (off % size != 0)
599                 return false;
600 
601         BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64));
602         return true;
603 }
604 
605 const struct bpf_verifier_ops tracepoint_prog_ops = {
606         .get_func_proto  = tp_prog_func_proto,
607         .is_valid_access = tp_prog_is_valid_access,
608 };
609 
610 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
611                                     struct bpf_insn_access_aux *info)
612 {
613         const int size_sp = FIELD_SIZEOF(struct bpf_perf_event_data,
614                                          sample_period);
615 
616         if (off < 0 || off >= sizeof(struct bpf_perf_event_data))
617                 return false;
618         if (type != BPF_READ)
619                 return false;
620         if (off % size != 0)
621                 return false;
622 
623         switch (off) {
624         case bpf_ctx_range(struct bpf_perf_event_data, sample_period):
625                 bpf_ctx_record_field_size(info, size_sp);
626                 if (!bpf_ctx_narrow_access_ok(off, size, size_sp))
627                         return false;
628                 break;
629         default:
630                 if (size != sizeof(long))
631                         return false;
632         }
633 
634         return true;
635 }
636 
637 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
638                                       const struct bpf_insn *si,
639                                       struct bpf_insn *insn_buf,
640                                       struct bpf_prog *prog, u32 *target_size)
641 {
642         struct bpf_insn *insn = insn_buf;
643 
644         switch (si->off) {
645         case offsetof(struct bpf_perf_event_data, sample_period):
646                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
647                                                        data), si->dst_reg, si->src_reg,
648                                       offsetof(struct bpf_perf_event_data_kern, data));
649                 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
650                                       bpf_target_off(struct perf_sample_data, period, 8,
651                                                      target_size));
652                 break;
653         default:
654                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
655                                                        regs), si->dst_reg, si->src_reg,
656                                       offsetof(struct bpf_perf_event_data_kern, regs));
657                 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg,
658                                       si->off);
659                 break;
660         }
661 
662         return insn - insn_buf;
663 }
664 
665 const struct bpf_verifier_ops perf_event_prog_ops = {
666         .get_func_proto         = tp_prog_func_proto,
667         .is_valid_access        = pe_prog_is_valid_access,
668         .convert_ctx_access     = pe_prog_convert_ctx_access,
669 };
670 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp