1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016,2017 Facebook
4 */
5 #include <linux/bpf.h>
6 #include <linux/btf.h>
7 #include <linux/err.h>
8 #include <linux/slab.h>
9 #include <linux/mm.h>
10 #include <linux/filter.h>
11 #include <linux/perf_event.h>
12 #include <uapi/linux/btf.h>
13 #include <linux/rcupdate_trace.h>
14 #include <linux/btf_ids.h>
15
16 #include "map_in_map.h"
17
18 #define ARRAY_CREATE_FLAG_MASK \
19 (BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
20 BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
21
bpf_array_free_percpu(struct bpf_array * array)22 static void bpf_array_free_percpu(struct bpf_array *array)
23 {
24 int i;
25
26 for (i = 0; i < array->map.max_entries; i++) {
27 free_percpu(array->pptrs[i]);
28 cond_resched();
29 }
30 }
31
bpf_array_alloc_percpu(struct bpf_array * array)32 static int bpf_array_alloc_percpu(struct bpf_array *array)
33 {
34 void __percpu *ptr;
35 int i;
36
37 for (i = 0; i < array->map.max_entries; i++) {
38 ptr = bpf_map_alloc_percpu(&array->map, array->elem_size, 8,
39 GFP_USER | __GFP_NOWARN);
40 if (!ptr) {
41 bpf_array_free_percpu(array);
42 return -ENOMEM;
43 }
44 array->pptrs[i] = ptr;
45 cond_resched();
46 }
47
48 return 0;
49 }
50
51 /* Called from syscall */
array_map_alloc_check(union bpf_attr * attr)52 int array_map_alloc_check(union bpf_attr *attr)
53 {
54 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
55 int numa_node = bpf_map_attr_numa_node(attr);
56
57 /* check sanity of attributes */
58 if (attr->max_entries == 0 || attr->key_size != 4 ||
59 attr->value_size == 0 ||
60 attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
61 !bpf_map_flags_access_ok(attr->map_flags) ||
62 (percpu && numa_node != NUMA_NO_NODE))
63 return -EINVAL;
64
65 if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
66 attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
67 return -EINVAL;
68
69 if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
70 attr->map_flags & BPF_F_PRESERVE_ELEMS)
71 return -EINVAL;
72
73 /* avoid overflow on round_up(map->value_size) */
74 if (attr->value_size > INT_MAX)
75 return -E2BIG;
76
77 return 0;
78 }
79
array_map_alloc(union bpf_attr * attr)80 static struct bpf_map *array_map_alloc(union bpf_attr *attr)
81 {
82 bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
83 int numa_node = bpf_map_attr_numa_node(attr);
84 u32 elem_size, index_mask, max_entries;
85 bool bypass_spec_v1 = bpf_bypass_spec_v1();
86 u64 array_size, mask64;
87 struct bpf_array *array;
88
89 elem_size = round_up(attr->value_size, 8);
90
91 max_entries = attr->max_entries;
92
93 /* On 32 bit archs roundup_pow_of_two() with max_entries that has
94 * upper most bit set in u32 space is undefined behavior due to
95 * resulting 1U << 32, so do it manually here in u64 space.
96 */
97 mask64 = fls_long(max_entries - 1);
98 mask64 = 1ULL << mask64;
99 mask64 -= 1;
100
101 index_mask = mask64;
102 if (!bypass_spec_v1) {
103 /* round up array size to nearest power of 2,
104 * since cpu will speculate within index_mask limits
105 */
106 max_entries = index_mask + 1;
107 /* Check for overflows. */
108 if (max_entries < attr->max_entries)
109 return ERR_PTR(-E2BIG);
110 }
111
112 array_size = sizeof(*array);
113 if (percpu) {
114 array_size += (u64) max_entries * sizeof(void *);
115 } else {
116 /* rely on vmalloc() to return page-aligned memory and
117 * ensure array->value is exactly page-aligned
118 */
119 if (attr->map_flags & BPF_F_MMAPABLE) {
120 array_size = PAGE_ALIGN(array_size);
121 array_size += PAGE_ALIGN((u64) max_entries * elem_size);
122 } else {
123 array_size += (u64) max_entries * elem_size;
124 }
125 }
126
127 /* allocate all map elements and zero-initialize them */
128 if (attr->map_flags & BPF_F_MMAPABLE) {
129 void *data;
130
131 /* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
132 data = bpf_map_area_mmapable_alloc(array_size, numa_node);
133 if (!data)
134 return ERR_PTR(-ENOMEM);
135 array = data + PAGE_ALIGN(sizeof(struct bpf_array))
136 - offsetof(struct bpf_array, value);
137 } else {
138 array = bpf_map_area_alloc(array_size, numa_node);
139 }
140 if (!array)
141 return ERR_PTR(-ENOMEM);
142 array->index_mask = index_mask;
143 array->map.bypass_spec_v1 = bypass_spec_v1;
144
145 /* copy mandatory map attributes */
146 bpf_map_init_from_attr(&array->map, attr);
147 array->elem_size = elem_size;
148
149 if (percpu && bpf_array_alloc_percpu(array)) {
150 bpf_map_area_free(array);
151 return ERR_PTR(-ENOMEM);
152 }
153
154 return &array->map;
155 }
156
array_map_elem_ptr(struct bpf_array * array,u32 index)157 static void *array_map_elem_ptr(struct bpf_array* array, u32 index)
158 {
159 return array->value + (u64)array->elem_size * index;
160 }
161
162 /* Called from syscall or from eBPF program */
array_map_lookup_elem(struct bpf_map * map,void * key)163 static void *array_map_lookup_elem(struct bpf_map *map, void *key)
164 {
165 struct bpf_array *array = container_of(map, struct bpf_array, map);
166 u32 index = *(u32 *)key;
167
168 if (unlikely(index >= array->map.max_entries))
169 return NULL;
170
171 return array->value + (u64)array->elem_size * (index & array->index_mask);
172 }
173
array_map_direct_value_addr(const struct bpf_map * map,u64 * imm,u32 off)174 static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
175 u32 off)
176 {
177 struct bpf_array *array = container_of(map, struct bpf_array, map);
178
179 if (map->max_entries != 1)
180 return -ENOTSUPP;
181 if (off >= map->value_size)
182 return -EINVAL;
183
184 *imm = (unsigned long)array->value;
185 return 0;
186 }
187
array_map_direct_value_meta(const struct bpf_map * map,u64 imm,u32 * off)188 static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
189 u32 *off)
190 {
191 struct bpf_array *array = container_of(map, struct bpf_array, map);
192 u64 base = (unsigned long)array->value;
193 u64 range = array->elem_size;
194
195 if (map->max_entries != 1)
196 return -ENOTSUPP;
197 if (imm < base || imm >= base + range)
198 return -ENOENT;
199
200 *off = imm - base;
201 return 0;
202 }
203
204 /* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
array_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)205 static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
206 {
207 struct bpf_array *array = container_of(map, struct bpf_array, map);
208 struct bpf_insn *insn = insn_buf;
209 u32 elem_size = array->elem_size;
210 const int ret = BPF_REG_0;
211 const int map_ptr = BPF_REG_1;
212 const int index = BPF_REG_2;
213
214 if (map->map_flags & BPF_F_INNER_MAP)
215 return -EOPNOTSUPP;
216
217 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
218 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
219 if (!map->bypass_spec_v1) {
220 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
221 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
222 } else {
223 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
224 }
225
226 if (is_power_of_2(elem_size)) {
227 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
228 } else {
229 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
230 }
231 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
232 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
233 *insn++ = BPF_MOV64_IMM(ret, 0);
234 return insn - insn_buf;
235 }
236
237 /* Called from eBPF program */
percpu_array_map_lookup_elem(struct bpf_map * map,void * key)238 static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
239 {
240 struct bpf_array *array = container_of(map, struct bpf_array, map);
241 u32 index = *(u32 *)key;
242
243 if (unlikely(index >= array->map.max_entries))
244 return NULL;
245
246 return this_cpu_ptr(array->pptrs[index & array->index_mask]);
247 }
248
percpu_array_map_lookup_percpu_elem(struct bpf_map * map,void * key,u32 cpu)249 static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
250 {
251 struct bpf_array *array = container_of(map, struct bpf_array, map);
252 u32 index = *(u32 *)key;
253
254 if (cpu >= nr_cpu_ids)
255 return NULL;
256
257 if (unlikely(index >= array->map.max_entries))
258 return NULL;
259
260 return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
261 }
262
bpf_percpu_array_copy(struct bpf_map * map,void * key,void * value)263 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
264 {
265 struct bpf_array *array = container_of(map, struct bpf_array, map);
266 u32 index = *(u32 *)key;
267 void __percpu *pptr;
268 int cpu, off = 0;
269 u32 size;
270
271 if (unlikely(index >= array->map.max_entries))
272 return -ENOENT;
273
274 /* per_cpu areas are zero-filled and bpf programs can only
275 * access 'value_size' of them, so copying rounded areas
276 * will not leak any kernel data
277 */
278 size = array->elem_size;
279 rcu_read_lock();
280 pptr = array->pptrs[index & array->index_mask];
281 for_each_possible_cpu(cpu) {
282 copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
283 check_and_init_map_value(map, value + off);
284 off += size;
285 }
286 rcu_read_unlock();
287 return 0;
288 }
289
290 /* Called from syscall */
array_map_get_next_key(struct bpf_map * map,void * key,void * next_key)291 static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
292 {
293 struct bpf_array *array = container_of(map, struct bpf_array, map);
294 u32 index = key ? *(u32 *)key : U32_MAX;
295 u32 *next = (u32 *)next_key;
296
297 if (index >= array->map.max_entries) {
298 *next = 0;
299 return 0;
300 }
301
302 if (index == array->map.max_entries - 1)
303 return -ENOENT;
304
305 *next = index + 1;
306 return 0;
307 }
308
check_and_free_fields(struct bpf_array * arr,void * val)309 static void check_and_free_fields(struct bpf_array *arr, void *val)
310 {
311 if (map_value_has_timer(&arr->map))
312 bpf_timer_cancel_and_free(val + arr->map.timer_off);
313 if (map_value_has_kptrs(&arr->map))
314 bpf_map_free_kptrs(&arr->map, val);
315 }
316
317 /* Called from syscall or from eBPF program */
array_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags)318 static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
319 u64 map_flags)
320 {
321 struct bpf_array *array = container_of(map, struct bpf_array, map);
322 u32 index = *(u32 *)key;
323 char *val;
324
325 if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
326 /* unknown flags */
327 return -EINVAL;
328
329 if (unlikely(index >= array->map.max_entries))
330 /* all elements were pre-allocated, cannot insert a new one */
331 return -E2BIG;
332
333 if (unlikely(map_flags & BPF_NOEXIST))
334 /* all elements already exist */
335 return -EEXIST;
336
337 if (unlikely((map_flags & BPF_F_LOCK) &&
338 !map_value_has_spin_lock(map)))
339 return -EINVAL;
340
341 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
342 val = this_cpu_ptr(array->pptrs[index & array->index_mask]);
343 copy_map_value(map, val, value);
344 check_and_free_fields(array, val);
345 } else {
346 val = array->value +
347 (u64)array->elem_size * (index & array->index_mask);
348 if (map_flags & BPF_F_LOCK)
349 copy_map_value_locked(map, val, value, false);
350 else
351 copy_map_value(map, val, value);
352 check_and_free_fields(array, val);
353 }
354 return 0;
355 }
356
bpf_percpu_array_update(struct bpf_map * map,void * key,void * value,u64 map_flags)357 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
358 u64 map_flags)
359 {
360 struct bpf_array *array = container_of(map, struct bpf_array, map);
361 u32 index = *(u32 *)key;
362 void __percpu *pptr;
363 int cpu, off = 0;
364 u32 size;
365
366 if (unlikely(map_flags > BPF_EXIST))
367 /* unknown flags */
368 return -EINVAL;
369
370 if (unlikely(index >= array->map.max_entries))
371 /* all elements were pre-allocated, cannot insert a new one */
372 return -E2BIG;
373
374 if (unlikely(map_flags == BPF_NOEXIST))
375 /* all elements already exist */
376 return -EEXIST;
377
378 /* the user space will provide round_up(value_size, 8) bytes that
379 * will be copied into per-cpu area. bpf programs can only access
380 * value_size of it. During lookup the same extra bytes will be
381 * returned or zeros which were zero-filled by percpu_alloc,
382 * so no kernel data leaks possible
383 */
384 size = array->elem_size;
385 rcu_read_lock();
386 pptr = array->pptrs[index & array->index_mask];
387 for_each_possible_cpu(cpu) {
388 copy_map_value_long(map, per_cpu_ptr(pptr, cpu), value + off);
389 check_and_free_fields(array, per_cpu_ptr(pptr, cpu));
390 off += size;
391 }
392 rcu_read_unlock();
393 return 0;
394 }
395
396 /* Called from syscall or from eBPF program */
array_map_delete_elem(struct bpf_map * map,void * key)397 static int array_map_delete_elem(struct bpf_map *map, void *key)
398 {
399 return -EINVAL;
400 }
401
array_map_vmalloc_addr(struct bpf_array * array)402 static void *array_map_vmalloc_addr(struct bpf_array *array)
403 {
404 return (void *)round_down((unsigned long)array, PAGE_SIZE);
405 }
406
array_map_free_timers(struct bpf_map * map)407 static void array_map_free_timers(struct bpf_map *map)
408 {
409 struct bpf_array *array = container_of(map, struct bpf_array, map);
410 int i;
411
412 /* We don't reset or free kptr on uref dropping to zero. */
413 if (!map_value_has_timer(map))
414 return;
415
416 for (i = 0; i < array->map.max_entries; i++)
417 bpf_timer_cancel_and_free(array_map_elem_ptr(array, i) + map->timer_off);
418 }
419
420 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
array_map_free(struct bpf_map * map)421 static void array_map_free(struct bpf_map *map)
422 {
423 struct bpf_array *array = container_of(map, struct bpf_array, map);
424 int i;
425
426 if (map_value_has_kptrs(map)) {
427 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
428 for (i = 0; i < array->map.max_entries; i++) {
429 void __percpu *pptr = array->pptrs[i & array->index_mask];
430 int cpu;
431
432 for_each_possible_cpu(cpu) {
433 bpf_map_free_kptrs(map, per_cpu_ptr(pptr, cpu));
434 cond_resched();
435 }
436 }
437 } else {
438 for (i = 0; i < array->map.max_entries; i++)
439 bpf_map_free_kptrs(map, array_map_elem_ptr(array, i));
440 }
441 bpf_map_free_kptr_off_tab(map);
442 }
443
444 if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
445 bpf_array_free_percpu(array);
446
447 if (array->map.map_flags & BPF_F_MMAPABLE)
448 bpf_map_area_free(array_map_vmalloc_addr(array));
449 else
450 bpf_map_area_free(array);
451 }
452
array_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)453 static void array_map_seq_show_elem(struct bpf_map *map, void *key,
454 struct seq_file *m)
455 {
456 void *value;
457
458 rcu_read_lock();
459
460 value = array_map_lookup_elem(map, key);
461 if (!value) {
462 rcu_read_unlock();
463 return;
464 }
465
466 if (map->btf_key_type_id)
467 seq_printf(m, "%u: ", *(u32 *)key);
468 btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
469 seq_puts(m, "\n");
470
471 rcu_read_unlock();
472 }
473
percpu_array_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)474 static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
475 struct seq_file *m)
476 {
477 struct bpf_array *array = container_of(map, struct bpf_array, map);
478 u32 index = *(u32 *)key;
479 void __percpu *pptr;
480 int cpu;
481
482 rcu_read_lock();
483
484 seq_printf(m, "%u: {\n", *(u32 *)key);
485 pptr = array->pptrs[index & array->index_mask];
486 for_each_possible_cpu(cpu) {
487 seq_printf(m, "\tcpu%d: ", cpu);
488 btf_type_seq_show(map->btf, map->btf_value_type_id,
489 per_cpu_ptr(pptr, cpu), m);
490 seq_puts(m, "\n");
491 }
492 seq_puts(m, "}\n");
493
494 rcu_read_unlock();
495 }
496
array_map_check_btf(const struct bpf_map * map,const struct btf * btf,const struct btf_type * key_type,const struct btf_type * value_type)497 static int array_map_check_btf(const struct bpf_map *map,
498 const struct btf *btf,
499 const struct btf_type *key_type,
500 const struct btf_type *value_type)
501 {
502 u32 int_data;
503
504 /* One exception for keyless BTF: .bss/.data/.rodata map */
505 if (btf_type_is_void(key_type)) {
506 if (map->map_type != BPF_MAP_TYPE_ARRAY ||
507 map->max_entries != 1)
508 return -EINVAL;
509
510 if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
511 return -EINVAL;
512
513 return 0;
514 }
515
516 if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
517 return -EINVAL;
518
519 int_data = *(u32 *)(key_type + 1);
520 /* bpf array can only take a u32 key. This check makes sure
521 * that the btf matches the attr used during map_create.
522 */
523 if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
524 return -EINVAL;
525
526 return 0;
527 }
528
array_map_mmap(struct bpf_map * map,struct vm_area_struct * vma)529 static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
530 {
531 struct bpf_array *array = container_of(map, struct bpf_array, map);
532 pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
533
534 if (!(map->map_flags & BPF_F_MMAPABLE))
535 return -EINVAL;
536
537 if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
538 PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
539 return -EINVAL;
540
541 return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
542 vma->vm_pgoff + pgoff);
543 }
544
array_map_meta_equal(const struct bpf_map * meta0,const struct bpf_map * meta1)545 static bool array_map_meta_equal(const struct bpf_map *meta0,
546 const struct bpf_map *meta1)
547 {
548 if (!bpf_map_meta_equal(meta0, meta1))
549 return false;
550 return meta0->map_flags & BPF_F_INNER_MAP ? true :
551 meta0->max_entries == meta1->max_entries;
552 }
553
554 struct bpf_iter_seq_array_map_info {
555 struct bpf_map *map;
556 void *percpu_value_buf;
557 u32 index;
558 };
559
bpf_array_map_seq_start(struct seq_file * seq,loff_t * pos)560 static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
561 {
562 struct bpf_iter_seq_array_map_info *info = seq->private;
563 struct bpf_map *map = info->map;
564 struct bpf_array *array;
565 u32 index;
566
567 if (info->index >= map->max_entries)
568 return NULL;
569
570 if (*pos == 0)
571 ++*pos;
572 array = container_of(map, struct bpf_array, map);
573 index = info->index & array->index_mask;
574 if (info->percpu_value_buf)
575 return array->pptrs[index];
576 return array_map_elem_ptr(array, index);
577 }
578
bpf_array_map_seq_next(struct seq_file * seq,void * v,loff_t * pos)579 static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
580 {
581 struct bpf_iter_seq_array_map_info *info = seq->private;
582 struct bpf_map *map = info->map;
583 struct bpf_array *array;
584 u32 index;
585
586 ++*pos;
587 ++info->index;
588 if (info->index >= map->max_entries)
589 return NULL;
590
591 array = container_of(map, struct bpf_array, map);
592 index = info->index & array->index_mask;
593 if (info->percpu_value_buf)
594 return array->pptrs[index];
595 return array_map_elem_ptr(array, index);
596 }
597
__bpf_array_map_seq_show(struct seq_file * seq,void * v)598 static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
599 {
600 struct bpf_iter_seq_array_map_info *info = seq->private;
601 struct bpf_iter__bpf_map_elem ctx = {};
602 struct bpf_map *map = info->map;
603 struct bpf_array *array = container_of(map, struct bpf_array, map);
604 struct bpf_iter_meta meta;
605 struct bpf_prog *prog;
606 int off = 0, cpu = 0;
607 void __percpu **pptr;
608 u32 size;
609
610 meta.seq = seq;
611 prog = bpf_iter_get_info(&meta, v == NULL);
612 if (!prog)
613 return 0;
614
615 ctx.meta = &meta;
616 ctx.map = info->map;
617 if (v) {
618 ctx.key = &info->index;
619
620 if (!info->percpu_value_buf) {
621 ctx.value = v;
622 } else {
623 pptr = v;
624 size = array->elem_size;
625 for_each_possible_cpu(cpu) {
626 copy_map_value_long(map, info->percpu_value_buf + off,
627 per_cpu_ptr(pptr, cpu));
628 check_and_init_map_value(map, info->percpu_value_buf + off);
629 off += size;
630 }
631 ctx.value = info->percpu_value_buf;
632 }
633 }
634
635 return bpf_iter_run_prog(prog, &ctx);
636 }
637
bpf_array_map_seq_show(struct seq_file * seq,void * v)638 static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
639 {
640 return __bpf_array_map_seq_show(seq, v);
641 }
642
bpf_array_map_seq_stop(struct seq_file * seq,void * v)643 static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
644 {
645 if (!v)
646 (void)__bpf_array_map_seq_show(seq, NULL);
647 }
648
bpf_iter_init_array_map(void * priv_data,struct bpf_iter_aux_info * aux)649 static int bpf_iter_init_array_map(void *priv_data,
650 struct bpf_iter_aux_info *aux)
651 {
652 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
653 struct bpf_map *map = aux->map;
654 struct bpf_array *array = container_of(map, struct bpf_array, map);
655 void *value_buf;
656 u32 buf_size;
657
658 if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
659 buf_size = array->elem_size * num_possible_cpus();
660 value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
661 if (!value_buf)
662 return -ENOMEM;
663
664 seq_info->percpu_value_buf = value_buf;
665 }
666
667 /* bpf_iter_attach_map() acquires a map uref, and the uref may be
668 * released before or in the middle of iterating map elements, so
669 * acquire an extra map uref for iterator.
670 */
671 bpf_map_inc_with_uref(map);
672 seq_info->map = map;
673 return 0;
674 }
675
bpf_iter_fini_array_map(void * priv_data)676 static void bpf_iter_fini_array_map(void *priv_data)
677 {
678 struct bpf_iter_seq_array_map_info *seq_info = priv_data;
679
680 bpf_map_put_with_uref(seq_info->map);
681 kfree(seq_info->percpu_value_buf);
682 }
683
684 static const struct seq_operations bpf_array_map_seq_ops = {
685 .start = bpf_array_map_seq_start,
686 .next = bpf_array_map_seq_next,
687 .stop = bpf_array_map_seq_stop,
688 .show = bpf_array_map_seq_show,
689 };
690
691 static const struct bpf_iter_seq_info iter_seq_info = {
692 .seq_ops = &bpf_array_map_seq_ops,
693 .init_seq_private = bpf_iter_init_array_map,
694 .fini_seq_private = bpf_iter_fini_array_map,
695 .seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
696 };
697
bpf_for_each_array_elem(struct bpf_map * map,bpf_callback_t callback_fn,void * callback_ctx,u64 flags)698 static int bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn,
699 void *callback_ctx, u64 flags)
700 {
701 u32 i, key, num_elems = 0;
702 struct bpf_array *array;
703 bool is_percpu;
704 u64 ret = 0;
705 void *val;
706
707 if (flags != 0)
708 return -EINVAL;
709
710 is_percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
711 array = container_of(map, struct bpf_array, map);
712 if (is_percpu)
713 migrate_disable();
714 for (i = 0; i < map->max_entries; i++) {
715 if (is_percpu)
716 val = this_cpu_ptr(array->pptrs[i]);
717 else
718 val = array_map_elem_ptr(array, i);
719 num_elems++;
720 key = i;
721 ret = callback_fn((u64)(long)map, (u64)(long)&key,
722 (u64)(long)val, (u64)(long)callback_ctx, 0);
723 /* return value: 0 - continue, 1 - stop and return */
724 if (ret)
725 break;
726 }
727
728 if (is_percpu)
729 migrate_enable();
730 return num_elems;
731 }
732
733 BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)
734 const struct bpf_map_ops array_map_ops = {
735 .map_meta_equal = array_map_meta_equal,
736 .map_alloc_check = array_map_alloc_check,
737 .map_alloc = array_map_alloc,
738 .map_free = array_map_free,
739 .map_get_next_key = array_map_get_next_key,
740 .map_release_uref = array_map_free_timers,
741 .map_lookup_elem = array_map_lookup_elem,
742 .map_update_elem = array_map_update_elem,
743 .map_delete_elem = array_map_delete_elem,
744 .map_gen_lookup = array_map_gen_lookup,
745 .map_direct_value_addr = array_map_direct_value_addr,
746 .map_direct_value_meta = array_map_direct_value_meta,
747 .map_mmap = array_map_mmap,
748 .map_seq_show_elem = array_map_seq_show_elem,
749 .map_check_btf = array_map_check_btf,
750 .map_lookup_batch = generic_map_lookup_batch,
751 .map_update_batch = generic_map_update_batch,
752 .map_set_for_each_callback_args = map_set_for_each_callback_args,
753 .map_for_each_callback = bpf_for_each_array_elem,
754 .map_btf_id = &array_map_btf_ids[0],
755 .iter_seq_info = &iter_seq_info,
756 };
757
758 const struct bpf_map_ops percpu_array_map_ops = {
759 .map_meta_equal = bpf_map_meta_equal,
760 .map_alloc_check = array_map_alloc_check,
761 .map_alloc = array_map_alloc,
762 .map_free = array_map_free,
763 .map_get_next_key = array_map_get_next_key,
764 .map_lookup_elem = percpu_array_map_lookup_elem,
765 .map_update_elem = array_map_update_elem,
766 .map_delete_elem = array_map_delete_elem,
767 .map_lookup_percpu_elem = percpu_array_map_lookup_percpu_elem,
768 .map_seq_show_elem = percpu_array_map_seq_show_elem,
769 .map_check_btf = array_map_check_btf,
770 .map_lookup_batch = generic_map_lookup_batch,
771 .map_update_batch = generic_map_update_batch,
772 .map_set_for_each_callback_args = map_set_for_each_callback_args,
773 .map_for_each_callback = bpf_for_each_array_elem,
774 .map_btf_id = &array_map_btf_ids[0],
775 .iter_seq_info = &iter_seq_info,
776 };
777
fd_array_map_alloc_check(union bpf_attr * attr)778 static int fd_array_map_alloc_check(union bpf_attr *attr)
779 {
780 /* only file descriptors can be stored in this type of map */
781 if (attr->value_size != sizeof(u32))
782 return -EINVAL;
783 /* Program read-only/write-only not supported for special maps yet. */
784 if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
785 return -EINVAL;
786 return array_map_alloc_check(attr);
787 }
788
fd_array_map_free(struct bpf_map * map)789 static void fd_array_map_free(struct bpf_map *map)
790 {
791 struct bpf_array *array = container_of(map, struct bpf_array, map);
792 int i;
793
794 /* make sure it's empty */
795 for (i = 0; i < array->map.max_entries; i++)
796 BUG_ON(array->ptrs[i] != NULL);
797
798 bpf_map_area_free(array);
799 }
800
fd_array_map_lookup_elem(struct bpf_map * map,void * key)801 static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
802 {
803 return ERR_PTR(-EOPNOTSUPP);
804 }
805
806 /* only called from syscall */
bpf_fd_array_map_lookup_elem(struct bpf_map * map,void * key,u32 * value)807 int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
808 {
809 void **elem, *ptr;
810 int ret = 0;
811
812 if (!map->ops->map_fd_sys_lookup_elem)
813 return -ENOTSUPP;
814
815 rcu_read_lock();
816 elem = array_map_lookup_elem(map, key);
817 if (elem && (ptr = READ_ONCE(*elem)))
818 *value = map->ops->map_fd_sys_lookup_elem(ptr);
819 else
820 ret = -ENOENT;
821 rcu_read_unlock();
822
823 return ret;
824 }
825
826 /* only called from syscall */
bpf_fd_array_map_update_elem(struct bpf_map * map,struct file * map_file,void * key,void * value,u64 map_flags)827 int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
828 void *key, void *value, u64 map_flags)
829 {
830 struct bpf_array *array = container_of(map, struct bpf_array, map);
831 void *new_ptr, *old_ptr;
832 u32 index = *(u32 *)key, ufd;
833
834 if (map_flags != BPF_ANY)
835 return -EINVAL;
836
837 if (index >= array->map.max_entries)
838 return -E2BIG;
839
840 ufd = *(u32 *)value;
841 new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
842 if (IS_ERR(new_ptr))
843 return PTR_ERR(new_ptr);
844
845 if (map->ops->map_poke_run) {
846 mutex_lock(&array->aux->poke_mutex);
847 old_ptr = xchg(array->ptrs + index, new_ptr);
848 map->ops->map_poke_run(map, index, old_ptr, new_ptr);
849 mutex_unlock(&array->aux->poke_mutex);
850 } else {
851 old_ptr = xchg(array->ptrs + index, new_ptr);
852 }
853
854 if (old_ptr)
855 map->ops->map_fd_put_ptr(old_ptr);
856 return 0;
857 }
858
fd_array_map_delete_elem(struct bpf_map * map,void * key)859 static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
860 {
861 struct bpf_array *array = container_of(map, struct bpf_array, map);
862 void *old_ptr;
863 u32 index = *(u32 *)key;
864
865 if (index >= array->map.max_entries)
866 return -E2BIG;
867
868 if (map->ops->map_poke_run) {
869 mutex_lock(&array->aux->poke_mutex);
870 old_ptr = xchg(array->ptrs + index, NULL);
871 map->ops->map_poke_run(map, index, old_ptr, NULL);
872 mutex_unlock(&array->aux->poke_mutex);
873 } else {
874 old_ptr = xchg(array->ptrs + index, NULL);
875 }
876
877 if (old_ptr) {
878 map->ops->map_fd_put_ptr(old_ptr);
879 return 0;
880 } else {
881 return -ENOENT;
882 }
883 }
884
prog_fd_array_get_ptr(struct bpf_map * map,struct file * map_file,int fd)885 static void *prog_fd_array_get_ptr(struct bpf_map *map,
886 struct file *map_file, int fd)
887 {
888 struct bpf_prog *prog = bpf_prog_get(fd);
889
890 if (IS_ERR(prog))
891 return prog;
892
893 if (!bpf_prog_map_compatible(map, prog)) {
894 bpf_prog_put(prog);
895 return ERR_PTR(-EINVAL);
896 }
897
898 return prog;
899 }
900
prog_fd_array_put_ptr(void * ptr)901 static void prog_fd_array_put_ptr(void *ptr)
902 {
903 bpf_prog_put(ptr);
904 }
905
prog_fd_array_sys_lookup_elem(void * ptr)906 static u32 prog_fd_array_sys_lookup_elem(void *ptr)
907 {
908 return ((struct bpf_prog *)ptr)->aux->id;
909 }
910
911 /* decrement refcnt of all bpf_progs that are stored in this map */
bpf_fd_array_map_clear(struct bpf_map * map)912 static void bpf_fd_array_map_clear(struct bpf_map *map)
913 {
914 struct bpf_array *array = container_of(map, struct bpf_array, map);
915 int i;
916
917 for (i = 0; i < array->map.max_entries; i++)
918 fd_array_map_delete_elem(map, &i);
919 }
920
prog_array_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)921 static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
922 struct seq_file *m)
923 {
924 void **elem, *ptr;
925 u32 prog_id;
926
927 rcu_read_lock();
928
929 elem = array_map_lookup_elem(map, key);
930 if (elem) {
931 ptr = READ_ONCE(*elem);
932 if (ptr) {
933 seq_printf(m, "%u: ", *(u32 *)key);
934 prog_id = prog_fd_array_sys_lookup_elem(ptr);
935 btf_type_seq_show(map->btf, map->btf_value_type_id,
936 &prog_id, m);
937 seq_puts(m, "\n");
938 }
939 }
940
941 rcu_read_unlock();
942 }
943
944 struct prog_poke_elem {
945 struct list_head list;
946 struct bpf_prog_aux *aux;
947 };
948
prog_array_map_poke_track(struct bpf_map * map,struct bpf_prog_aux * prog_aux)949 static int prog_array_map_poke_track(struct bpf_map *map,
950 struct bpf_prog_aux *prog_aux)
951 {
952 struct prog_poke_elem *elem;
953 struct bpf_array_aux *aux;
954 int ret = 0;
955
956 aux = container_of(map, struct bpf_array, map)->aux;
957 mutex_lock(&aux->poke_mutex);
958 list_for_each_entry(elem, &aux->poke_progs, list) {
959 if (elem->aux == prog_aux)
960 goto out;
961 }
962
963 elem = kmalloc(sizeof(*elem), GFP_KERNEL);
964 if (!elem) {
965 ret = -ENOMEM;
966 goto out;
967 }
968
969 INIT_LIST_HEAD(&elem->list);
970 /* We must track the program's aux info at this point in time
971 * since the program pointer itself may not be stable yet, see
972 * also comment in prog_array_map_poke_run().
973 */
974 elem->aux = prog_aux;
975
976 list_add_tail(&elem->list, &aux->poke_progs);
977 out:
978 mutex_unlock(&aux->poke_mutex);
979 return ret;
980 }
981
prog_array_map_poke_untrack(struct bpf_map * map,struct bpf_prog_aux * prog_aux)982 static void prog_array_map_poke_untrack(struct bpf_map *map,
983 struct bpf_prog_aux *prog_aux)
984 {
985 struct prog_poke_elem *elem, *tmp;
986 struct bpf_array_aux *aux;
987
988 aux = container_of(map, struct bpf_array, map)->aux;
989 mutex_lock(&aux->poke_mutex);
990 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
991 if (elem->aux == prog_aux) {
992 list_del_init(&elem->list);
993 kfree(elem);
994 break;
995 }
996 }
997 mutex_unlock(&aux->poke_mutex);
998 }
999
prog_array_map_poke_run(struct bpf_map * map,u32 key,struct bpf_prog * old,struct bpf_prog * new)1000 static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
1001 struct bpf_prog *old,
1002 struct bpf_prog *new)
1003 {
1004 u8 *old_addr, *new_addr, *old_bypass_addr;
1005 struct prog_poke_elem *elem;
1006 struct bpf_array_aux *aux;
1007
1008 aux = container_of(map, struct bpf_array, map)->aux;
1009 WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
1010
1011 list_for_each_entry(elem, &aux->poke_progs, list) {
1012 struct bpf_jit_poke_descriptor *poke;
1013 int i, ret;
1014
1015 for (i = 0; i < elem->aux->size_poke_tab; i++) {
1016 poke = &elem->aux->poke_tab[i];
1017
1018 /* Few things to be aware of:
1019 *
1020 * 1) We can only ever access aux in this context, but
1021 * not aux->prog since it might not be stable yet and
1022 * there could be danger of use after free otherwise.
1023 * 2) Initially when we start tracking aux, the program
1024 * is not JITed yet and also does not have a kallsyms
1025 * entry. We skip these as poke->tailcall_target_stable
1026 * is not active yet. The JIT will do the final fixup
1027 * before setting it stable. The various
1028 * poke->tailcall_target_stable are successively
1029 * activated, so tail call updates can arrive from here
1030 * while JIT is still finishing its final fixup for
1031 * non-activated poke entries.
1032 * 3) On program teardown, the program's kallsym entry gets
1033 * removed out of RCU callback, but we can only untrack
1034 * from sleepable context, therefore bpf_arch_text_poke()
1035 * might not see that this is in BPF text section and
1036 * bails out with -EINVAL. As these are unreachable since
1037 * RCU grace period already passed, we simply skip them.
1038 * 4) Also programs reaching refcount of zero while patching
1039 * is in progress is okay since we're protected under
1040 * poke_mutex and untrack the programs before the JIT
1041 * buffer is freed. When we're still in the middle of
1042 * patching and suddenly kallsyms entry of the program
1043 * gets evicted, we just skip the rest which is fine due
1044 * to point 3).
1045 * 5) Any other error happening below from bpf_arch_text_poke()
1046 * is a unexpected bug.
1047 */
1048 if (!READ_ONCE(poke->tailcall_target_stable))
1049 continue;
1050 if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
1051 continue;
1052 if (poke->tail_call.map != map ||
1053 poke->tail_call.key != key)
1054 continue;
1055
1056 old_bypass_addr = old ? NULL : poke->bypass_addr;
1057 old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
1058 new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
1059
1060 if (new) {
1061 ret = bpf_arch_text_poke(poke->tailcall_target,
1062 BPF_MOD_JUMP,
1063 old_addr, new_addr);
1064 BUG_ON(ret < 0 && ret != -EINVAL);
1065 if (!old) {
1066 ret = bpf_arch_text_poke(poke->tailcall_bypass,
1067 BPF_MOD_JUMP,
1068 poke->bypass_addr,
1069 NULL);
1070 BUG_ON(ret < 0 && ret != -EINVAL);
1071 }
1072 } else {
1073 ret = bpf_arch_text_poke(poke->tailcall_bypass,
1074 BPF_MOD_JUMP,
1075 old_bypass_addr,
1076 poke->bypass_addr);
1077 BUG_ON(ret < 0 && ret != -EINVAL);
1078 /* let other CPUs finish the execution of program
1079 * so that it will not possible to expose them
1080 * to invalid nop, stack unwind, nop state
1081 */
1082 if (!ret)
1083 synchronize_rcu();
1084 ret = bpf_arch_text_poke(poke->tailcall_target,
1085 BPF_MOD_JUMP,
1086 old_addr, NULL);
1087 BUG_ON(ret < 0 && ret != -EINVAL);
1088 }
1089 }
1090 }
1091 }
1092
prog_array_map_clear_deferred(struct work_struct * work)1093 static void prog_array_map_clear_deferred(struct work_struct *work)
1094 {
1095 struct bpf_map *map = container_of(work, struct bpf_array_aux,
1096 work)->map;
1097 bpf_fd_array_map_clear(map);
1098 bpf_map_put(map);
1099 }
1100
prog_array_map_clear(struct bpf_map * map)1101 static void prog_array_map_clear(struct bpf_map *map)
1102 {
1103 struct bpf_array_aux *aux = container_of(map, struct bpf_array,
1104 map)->aux;
1105 bpf_map_inc(map);
1106 schedule_work(&aux->work);
1107 }
1108
prog_array_map_alloc(union bpf_attr * attr)1109 static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
1110 {
1111 struct bpf_array_aux *aux;
1112 struct bpf_map *map;
1113
1114 aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT);
1115 if (!aux)
1116 return ERR_PTR(-ENOMEM);
1117
1118 INIT_WORK(&aux->work, prog_array_map_clear_deferred);
1119 INIT_LIST_HEAD(&aux->poke_progs);
1120 mutex_init(&aux->poke_mutex);
1121
1122 map = array_map_alloc(attr);
1123 if (IS_ERR(map)) {
1124 kfree(aux);
1125 return map;
1126 }
1127
1128 container_of(map, struct bpf_array, map)->aux = aux;
1129 aux->map = map;
1130
1131 return map;
1132 }
1133
prog_array_map_free(struct bpf_map * map)1134 static void prog_array_map_free(struct bpf_map *map)
1135 {
1136 struct prog_poke_elem *elem, *tmp;
1137 struct bpf_array_aux *aux;
1138
1139 aux = container_of(map, struct bpf_array, map)->aux;
1140 list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
1141 list_del_init(&elem->list);
1142 kfree(elem);
1143 }
1144 kfree(aux);
1145 fd_array_map_free(map);
1146 }
1147
1148 /* prog_array->aux->{type,jited} is a runtime binding.
1149 * Doing static check alone in the verifier is not enough.
1150 * Thus, prog_array_map cannot be used as an inner_map
1151 * and map_meta_equal is not implemented.
1152 */
1153 const struct bpf_map_ops prog_array_map_ops = {
1154 .map_alloc_check = fd_array_map_alloc_check,
1155 .map_alloc = prog_array_map_alloc,
1156 .map_free = prog_array_map_free,
1157 .map_poke_track = prog_array_map_poke_track,
1158 .map_poke_untrack = prog_array_map_poke_untrack,
1159 .map_poke_run = prog_array_map_poke_run,
1160 .map_get_next_key = array_map_get_next_key,
1161 .map_lookup_elem = fd_array_map_lookup_elem,
1162 .map_delete_elem = fd_array_map_delete_elem,
1163 .map_fd_get_ptr = prog_fd_array_get_ptr,
1164 .map_fd_put_ptr = prog_fd_array_put_ptr,
1165 .map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
1166 .map_release_uref = prog_array_map_clear,
1167 .map_seq_show_elem = prog_array_map_seq_show_elem,
1168 .map_btf_id = &array_map_btf_ids[0],
1169 };
1170
bpf_event_entry_gen(struct file * perf_file,struct file * map_file)1171 static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
1172 struct file *map_file)
1173 {
1174 struct bpf_event_entry *ee;
1175
1176 ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
1177 if (ee) {
1178 ee->event = perf_file->private_data;
1179 ee->perf_file = perf_file;
1180 ee->map_file = map_file;
1181 }
1182
1183 return ee;
1184 }
1185
__bpf_event_entry_free(struct rcu_head * rcu)1186 static void __bpf_event_entry_free(struct rcu_head *rcu)
1187 {
1188 struct bpf_event_entry *ee;
1189
1190 ee = container_of(rcu, struct bpf_event_entry, rcu);
1191 fput(ee->perf_file);
1192 kfree(ee);
1193 }
1194
bpf_event_entry_free_rcu(struct bpf_event_entry * ee)1195 static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
1196 {
1197 call_rcu(&ee->rcu, __bpf_event_entry_free);
1198 }
1199
perf_event_fd_array_get_ptr(struct bpf_map * map,struct file * map_file,int fd)1200 static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
1201 struct file *map_file, int fd)
1202 {
1203 struct bpf_event_entry *ee;
1204 struct perf_event *event;
1205 struct file *perf_file;
1206 u64 value;
1207
1208 perf_file = perf_event_get(fd);
1209 if (IS_ERR(perf_file))
1210 return perf_file;
1211
1212 ee = ERR_PTR(-EOPNOTSUPP);
1213 event = perf_file->private_data;
1214 if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
1215 goto err_out;
1216
1217 ee = bpf_event_entry_gen(perf_file, map_file);
1218 if (ee)
1219 return ee;
1220 ee = ERR_PTR(-ENOMEM);
1221 err_out:
1222 fput(perf_file);
1223 return ee;
1224 }
1225
perf_event_fd_array_put_ptr(void * ptr)1226 static void perf_event_fd_array_put_ptr(void *ptr)
1227 {
1228 bpf_event_entry_free_rcu(ptr);
1229 }
1230
perf_event_fd_array_release(struct bpf_map * map,struct file * map_file)1231 static void perf_event_fd_array_release(struct bpf_map *map,
1232 struct file *map_file)
1233 {
1234 struct bpf_array *array = container_of(map, struct bpf_array, map);
1235 struct bpf_event_entry *ee;
1236 int i;
1237
1238 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1239 return;
1240
1241 rcu_read_lock();
1242 for (i = 0; i < array->map.max_entries; i++) {
1243 ee = READ_ONCE(array->ptrs[i]);
1244 if (ee && ee->map_file == map_file)
1245 fd_array_map_delete_elem(map, &i);
1246 }
1247 rcu_read_unlock();
1248 }
1249
perf_event_fd_array_map_free(struct bpf_map * map)1250 static void perf_event_fd_array_map_free(struct bpf_map *map)
1251 {
1252 if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1253 bpf_fd_array_map_clear(map);
1254 fd_array_map_free(map);
1255 }
1256
1257 const struct bpf_map_ops perf_event_array_map_ops = {
1258 .map_meta_equal = bpf_map_meta_equal,
1259 .map_alloc_check = fd_array_map_alloc_check,
1260 .map_alloc = array_map_alloc,
1261 .map_free = perf_event_fd_array_map_free,
1262 .map_get_next_key = array_map_get_next_key,
1263 .map_lookup_elem = fd_array_map_lookup_elem,
1264 .map_delete_elem = fd_array_map_delete_elem,
1265 .map_fd_get_ptr = perf_event_fd_array_get_ptr,
1266 .map_fd_put_ptr = perf_event_fd_array_put_ptr,
1267 .map_release = perf_event_fd_array_release,
1268 .map_check_btf = map_check_no_btf,
1269 .map_btf_id = &array_map_btf_ids[0],
1270 };
1271
1272 #ifdef CONFIG_CGROUPS
cgroup_fd_array_get_ptr(struct bpf_map * map,struct file * map_file,int fd)1273 static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
1274 struct file *map_file /* not used */,
1275 int fd)
1276 {
1277 return cgroup_get_from_fd(fd);
1278 }
1279
cgroup_fd_array_put_ptr(void * ptr)1280 static void cgroup_fd_array_put_ptr(void *ptr)
1281 {
1282 /* cgroup_put free cgrp after a rcu grace period */
1283 cgroup_put(ptr);
1284 }
1285
cgroup_fd_array_free(struct bpf_map * map)1286 static void cgroup_fd_array_free(struct bpf_map *map)
1287 {
1288 bpf_fd_array_map_clear(map);
1289 fd_array_map_free(map);
1290 }
1291
1292 const struct bpf_map_ops cgroup_array_map_ops = {
1293 .map_meta_equal = bpf_map_meta_equal,
1294 .map_alloc_check = fd_array_map_alloc_check,
1295 .map_alloc = array_map_alloc,
1296 .map_free = cgroup_fd_array_free,
1297 .map_get_next_key = array_map_get_next_key,
1298 .map_lookup_elem = fd_array_map_lookup_elem,
1299 .map_delete_elem = fd_array_map_delete_elem,
1300 .map_fd_get_ptr = cgroup_fd_array_get_ptr,
1301 .map_fd_put_ptr = cgroup_fd_array_put_ptr,
1302 .map_check_btf = map_check_no_btf,
1303 .map_btf_id = &array_map_btf_ids[0],
1304 };
1305 #endif
1306
array_of_map_alloc(union bpf_attr * attr)1307 static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
1308 {
1309 struct bpf_map *map, *inner_map_meta;
1310
1311 inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
1312 if (IS_ERR(inner_map_meta))
1313 return inner_map_meta;
1314
1315 map = array_map_alloc(attr);
1316 if (IS_ERR(map)) {
1317 bpf_map_meta_free(inner_map_meta);
1318 return map;
1319 }
1320
1321 map->inner_map_meta = inner_map_meta;
1322
1323 return map;
1324 }
1325
array_of_map_free(struct bpf_map * map)1326 static void array_of_map_free(struct bpf_map *map)
1327 {
1328 /* map->inner_map_meta is only accessed by syscall which
1329 * is protected by fdget/fdput.
1330 */
1331 bpf_map_meta_free(map->inner_map_meta);
1332 bpf_fd_array_map_clear(map);
1333 fd_array_map_free(map);
1334 }
1335
array_of_map_lookup_elem(struct bpf_map * map,void * key)1336 static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
1337 {
1338 struct bpf_map **inner_map = array_map_lookup_elem(map, key);
1339
1340 if (!inner_map)
1341 return NULL;
1342
1343 return READ_ONCE(*inner_map);
1344 }
1345
array_of_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)1346 static int array_of_map_gen_lookup(struct bpf_map *map,
1347 struct bpf_insn *insn_buf)
1348 {
1349 struct bpf_array *array = container_of(map, struct bpf_array, map);
1350 u32 elem_size = array->elem_size;
1351 struct bpf_insn *insn = insn_buf;
1352 const int ret = BPF_REG_0;
1353 const int map_ptr = BPF_REG_1;
1354 const int index = BPF_REG_2;
1355
1356 *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
1357 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
1358 if (!map->bypass_spec_v1) {
1359 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
1360 *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
1361 } else {
1362 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
1363 }
1364 if (is_power_of_2(elem_size))
1365 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
1366 else
1367 *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
1368 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
1369 *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1370 *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
1371 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
1372 *insn++ = BPF_MOV64_IMM(ret, 0);
1373
1374 return insn - insn_buf;
1375 }
1376
1377 const struct bpf_map_ops array_of_maps_map_ops = {
1378 .map_alloc_check = fd_array_map_alloc_check,
1379 .map_alloc = array_of_map_alloc,
1380 .map_free = array_of_map_free,
1381 .map_get_next_key = array_map_get_next_key,
1382 .map_lookup_elem = array_of_map_lookup_elem,
1383 .map_delete_elem = fd_array_map_delete_elem,
1384 .map_fd_get_ptr = bpf_map_fd_get_ptr,
1385 .map_fd_put_ptr = bpf_map_fd_put_ptr,
1386 .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1387 .map_gen_lookup = array_of_map_gen_lookup,
1388 .map_lookup_batch = generic_map_lookup_batch,
1389 .map_update_batch = generic_map_update_batch,
1390 .map_check_btf = map_check_no_btf,
1391 .map_btf_id = &array_map_btf_ids[0],
1392 };
1393