1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
7 * This program is distributed in the hope that it will be useful, but
8 * WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * General Public License for more details.
12 #include <linux/bpf.h>
13 #include <linux/syscalls.h>
14 #include <linux/slab.h>
15 #include <linux/anon_inodes.h>
16 #include <linux/file.h>
17 #include <linux/license.h>
18 #include <linux/filter.h>
19 #include <linux/version.h>
21 int sysctl_unprivileged_bpf_disabled __read_mostly;
23 static LIST_HEAD(bpf_map_types);
25 static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
27 struct bpf_map_type_list *tl;
30 list_for_each_entry(tl, &bpf_map_types, list_node) {
31 if (tl->type == attr->map_type) {
32 map = tl->ops->map_alloc(attr);
36 map->map_type = attr->map_type;
40 return ERR_PTR(-EINVAL);
43 /* boot time registration of different map implementations */
44 void bpf_register_map_type(struct bpf_map_type_list *tl)
46 list_add(&tl->list_node, &bpf_map_types);
49 static int bpf_map_charge_memlock(struct bpf_map *map)
51 struct user_struct *user = get_current_user();
52 unsigned long memlock_limit;
54 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
56 atomic_long_add(map->pages, &user->locked_vm);
58 if (atomic_long_read(&user->locked_vm) > memlock_limit) {
59 atomic_long_sub(map->pages, &user->locked_vm);
67 static void bpf_map_uncharge_memlock(struct bpf_map *map)
69 struct user_struct *user = map->user;
71 atomic_long_sub(map->pages, &user->locked_vm);
75 /* called from workqueue */
76 static void bpf_map_free_deferred(struct work_struct *work)
78 struct bpf_map *map = container_of(work, struct bpf_map, work);
80 bpf_map_uncharge_memlock(map);
81 /* implementation dependent freeing */
82 map->ops->map_free(map);
85 static void bpf_map_put_uref(struct bpf_map *map)
87 if (atomic_dec_and_test(&map->usercnt)) {
88 if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY)
89 bpf_fd_array_map_clear(map);
93 /* decrement map refcnt and schedule it for freeing via workqueue
94 * (unrelying map implementation ops->map_free() might sleep)
96 void bpf_map_put(struct bpf_map *map)
98 if (atomic_dec_and_test(&map->refcnt)) {
99 INIT_WORK(&map->work, bpf_map_free_deferred);
100 schedule_work(&map->work);
104 void bpf_map_put_with_uref(struct bpf_map *map)
106 bpf_map_put_uref(map);
110 static int bpf_map_release(struct inode *inode, struct file *filp)
112 bpf_map_put_with_uref(filp->private_data);
116 #ifdef CONFIG_PROC_FS
117 static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
119 const struct bpf_map *map = filp->private_data;
125 "max_entries:\t%u\n",
133 static const struct file_operations bpf_map_fops = {
134 #ifdef CONFIG_PROC_FS
135 .show_fdinfo = bpf_map_show_fdinfo,
137 .release = bpf_map_release,
140 int bpf_map_new_fd(struct bpf_map *map)
142 return anon_inode_getfd("bpf-map", &bpf_map_fops, map,
146 /* helper macro to check that unused fields 'union bpf_attr' are zero */
147 #define CHECK_ATTR(CMD) \
148 memchr_inv((void *) &attr->CMD##_LAST_FIELD + \
149 sizeof(attr->CMD##_LAST_FIELD), 0, \
151 offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
152 sizeof(attr->CMD##_LAST_FIELD)) != NULL
154 #define BPF_MAP_CREATE_LAST_FIELD max_entries
155 /* called via syscall */
156 static int map_create(union bpf_attr *attr)
161 err = CHECK_ATTR(BPF_MAP_CREATE);
165 /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
166 map = find_and_alloc_map(attr);
170 atomic_set(&map->refcnt, 1);
171 atomic_set(&map->usercnt, 1);
173 err = bpf_map_charge_memlock(map);
177 err = bpf_map_new_fd(map);
179 /* failed to allocate fd */
185 map->ops->map_free(map);
189 /* if error is returned, fd is released.
190 * On success caller should complete fd access with matching fdput()
192 struct bpf_map *__bpf_map_get(struct fd f)
195 return ERR_PTR(-EBADF);
196 if (f.file->f_op != &bpf_map_fops) {
198 return ERR_PTR(-EINVAL);
201 return f.file->private_data;
204 void bpf_map_inc(struct bpf_map *map, bool uref)
206 atomic_inc(&map->refcnt);
208 atomic_inc(&map->usercnt);
211 struct bpf_map *bpf_map_get_with_uref(u32 ufd)
213 struct fd f = fdget(ufd);
216 map = __bpf_map_get(f);
220 bpf_map_inc(map, true);
226 /* helper to convert user pointers passed inside __aligned_u64 fields */
227 static void __user *u64_to_ptr(__u64 val)
229 return (void __user *) (unsigned long) val;
232 /* last field in 'union bpf_attr' used by this command */
233 #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
235 static int map_lookup_elem(union bpf_attr *attr)
237 void __user *ukey = u64_to_ptr(attr->key);
238 void __user *uvalue = u64_to_ptr(attr->value);
239 int ufd = attr->map_fd;
241 void *key, *value, *ptr;
246 if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
250 map = __bpf_map_get(f);
255 key = kmalloc(map->key_size, GFP_USER);
260 if (copy_from_user(key, ukey, map->key_size) != 0)
263 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
264 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
265 value_size = round_up(map->value_size, 8) * num_possible_cpus();
267 value_size = map->value_size;
270 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
274 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
275 err = bpf_percpu_hash_copy(map, key, value);
276 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
277 err = bpf_percpu_array_copy(map, key, value);
280 ptr = map->ops->map_lookup_elem(map, key);
282 memcpy(value, ptr, value_size);
284 err = ptr ? 0 : -ENOENT;
291 if (copy_to_user(uvalue, value, value_size) != 0)
305 #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
307 static int map_update_elem(union bpf_attr *attr)
309 void __user *ukey = u64_to_ptr(attr->key);
310 void __user *uvalue = u64_to_ptr(attr->value);
311 int ufd = attr->map_fd;
318 if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM))
322 map = __bpf_map_get(f);
327 key = kmalloc(map->key_size, GFP_USER);
332 if (copy_from_user(key, ukey, map->key_size) != 0)
335 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
336 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
337 value_size = round_up(map->value_size, 8) * num_possible_cpus();
339 value_size = map->value_size;
342 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
347 if (copy_from_user(value, uvalue, value_size) != 0)
350 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
351 err = bpf_percpu_hash_update(map, key, value, attr->flags);
352 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
353 err = bpf_percpu_array_update(map, key, value, attr->flags);
356 err = map->ops->map_update_elem(map, key, value, attr->flags);
369 #define BPF_MAP_DELETE_ELEM_LAST_FIELD key
371 static int map_delete_elem(union bpf_attr *attr)
373 void __user *ukey = u64_to_ptr(attr->key);
374 int ufd = attr->map_fd;
380 if (CHECK_ATTR(BPF_MAP_DELETE_ELEM))
384 map = __bpf_map_get(f);
389 key = kmalloc(map->key_size, GFP_USER);
394 if (copy_from_user(key, ukey, map->key_size) != 0)
398 err = map->ops->map_delete_elem(map, key);
408 /* last field in 'union bpf_attr' used by this command */
409 #define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key
411 static int map_get_next_key(union bpf_attr *attr)
413 void __user *ukey = u64_to_ptr(attr->key);
414 void __user *unext_key = u64_to_ptr(attr->next_key);
415 int ufd = attr->map_fd;
417 void *key, *next_key;
421 if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY))
425 map = __bpf_map_get(f);
430 key = kmalloc(map->key_size, GFP_USER);
435 if (copy_from_user(key, ukey, map->key_size) != 0)
439 next_key = kmalloc(map->key_size, GFP_USER);
444 err = map->ops->map_get_next_key(map, key, next_key);
450 if (copy_to_user(unext_key, next_key, map->key_size) != 0)
464 static LIST_HEAD(bpf_prog_types);
466 static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
468 struct bpf_prog_type_list *tl;
470 list_for_each_entry(tl, &bpf_prog_types, list_node) {
471 if (tl->type == type) {
472 prog->aux->ops = tl->ops;
481 void bpf_register_prog_type(struct bpf_prog_type_list *tl)
483 list_add(&tl->list_node, &bpf_prog_types);
486 /* fixup insn->imm field of bpf_call instructions:
487 * if (insn->imm == BPF_FUNC_map_lookup_elem)
488 * insn->imm = bpf_map_lookup_elem - __bpf_call_base;
489 * else if (insn->imm == BPF_FUNC_map_update_elem)
490 * insn->imm = bpf_map_update_elem - __bpf_call_base;
493 * this function is called after eBPF program passed verification
495 static void fixup_bpf_calls(struct bpf_prog *prog)
497 const struct bpf_func_proto *fn;
500 for (i = 0; i < prog->len; i++) {
501 struct bpf_insn *insn = &prog->insnsi[i];
503 if (insn->code == (BPF_JMP | BPF_CALL)) {
504 /* we reach here when program has bpf_call instructions
505 * and it passed bpf_check(), means that
506 * ops->get_func_proto must have been supplied, check it
508 BUG_ON(!prog->aux->ops->get_func_proto);
510 if (insn->imm == BPF_FUNC_get_route_realm)
511 prog->dst_needed = 1;
512 if (insn->imm == BPF_FUNC_get_prandom_u32)
513 bpf_user_rnd_init_once();
514 if (insn->imm == BPF_FUNC_tail_call) {
515 /* mark bpf_tail_call as different opcode
516 * to avoid conditional branch in
517 * interpeter for every normal call
518 * and to prevent accidental JITing by
519 * JIT compiler that doesn't support
527 fn = prog->aux->ops->get_func_proto(insn->imm);
528 /* all functions that have prototype and verifier allowed
529 * programs to call them, must be real in-kernel functions
532 insn->imm = fn->func - __bpf_call_base;
537 /* drop refcnt on maps used by eBPF program and free auxilary data */
538 static void free_used_maps(struct bpf_prog_aux *aux)
542 for (i = 0; i < aux->used_map_cnt; i++)
543 bpf_map_put(aux->used_maps[i]);
545 kfree(aux->used_maps);
548 static int bpf_prog_charge_memlock(struct bpf_prog *prog)
550 struct user_struct *user = get_current_user();
551 unsigned long memlock_limit;
553 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
555 atomic_long_add(prog->pages, &user->locked_vm);
556 if (atomic_long_read(&user->locked_vm) > memlock_limit) {
557 atomic_long_sub(prog->pages, &user->locked_vm);
561 prog->aux->user = user;
565 static void bpf_prog_uncharge_memlock(struct bpf_prog *prog)
567 struct user_struct *user = prog->aux->user;
569 atomic_long_sub(prog->pages, &user->locked_vm);
573 static void __prog_put_common(struct rcu_head *rcu)
575 struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
578 bpf_prog_uncharge_memlock(aux->prog);
579 bpf_prog_free(aux->prog);
582 /* version of bpf_prog_put() that is called after a grace period */
583 void bpf_prog_put_rcu(struct bpf_prog *prog)
585 if (atomic_dec_and_test(&prog->aux->refcnt))
586 call_rcu(&prog->aux->rcu, __prog_put_common);
589 void bpf_prog_put(struct bpf_prog *prog)
591 if (atomic_dec_and_test(&prog->aux->refcnt))
592 __prog_put_common(&prog->aux->rcu);
594 EXPORT_SYMBOL_GPL(bpf_prog_put);
596 static int bpf_prog_release(struct inode *inode, struct file *filp)
598 struct bpf_prog *prog = filp->private_data;
600 bpf_prog_put_rcu(prog);
604 static const struct file_operations bpf_prog_fops = {
605 .release = bpf_prog_release,
608 int bpf_prog_new_fd(struct bpf_prog *prog)
610 return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog,
614 static struct bpf_prog *__bpf_prog_get(struct fd f)
617 return ERR_PTR(-EBADF);
618 if (f.file->f_op != &bpf_prog_fops) {
620 return ERR_PTR(-EINVAL);
623 return f.file->private_data;
626 /* called by sockets/tracing/seccomp before attaching program to an event
627 * pairs with bpf_prog_put()
629 struct bpf_prog *bpf_prog_get(u32 ufd)
631 struct fd f = fdget(ufd);
632 struct bpf_prog *prog;
634 prog = __bpf_prog_get(f);
638 atomic_inc(&prog->aux->refcnt);
643 EXPORT_SYMBOL_GPL(bpf_prog_get);
645 /* last field in 'union bpf_attr' used by this command */
646 #define BPF_PROG_LOAD_LAST_FIELD kern_version
648 static int bpf_prog_load(union bpf_attr *attr)
650 enum bpf_prog_type type = attr->prog_type;
651 struct bpf_prog *prog;
656 if (CHECK_ATTR(BPF_PROG_LOAD))
659 /* copy eBPF program license from user space */
660 if (strncpy_from_user(license, u64_to_ptr(attr->license),
661 sizeof(license) - 1) < 0)
663 license[sizeof(license) - 1] = 0;
665 /* eBPF programs must be GPL compatible to use GPL-ed functions */
666 is_gpl = license_is_gpl_compatible(license);
668 if (attr->insn_cnt >= BPF_MAXINSNS)
671 if (type == BPF_PROG_TYPE_KPROBE &&
672 attr->kern_version != LINUX_VERSION_CODE)
675 if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN))
678 /* plain bpf_prog allocation */
679 prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
683 err = bpf_prog_charge_memlock(prog);
685 goto free_prog_nouncharge;
687 prog->len = attr->insn_cnt;
690 if (copy_from_user(prog->insns, u64_to_ptr(attr->insns),
691 prog->len * sizeof(struct bpf_insn)) != 0)
694 prog->orig_prog = NULL;
697 atomic_set(&prog->aux->refcnt, 1);
698 prog->gpl_compatible = is_gpl ? 1 : 0;
700 /* find program type: socket_filter vs tracing_filter */
701 err = find_prog_type(type, prog);
705 /* run eBPF verifier */
706 err = bpf_check(&prog, attr);
710 /* fixup BPF_CALL->imm field */
711 fixup_bpf_calls(prog);
713 /* eBPF program is ready to be JITed */
714 err = bpf_prog_select_runtime(prog);
718 err = bpf_prog_new_fd(prog);
720 /* failed to allocate fd */
726 free_used_maps(prog->aux);
728 bpf_prog_uncharge_memlock(prog);
729 free_prog_nouncharge:
734 #define BPF_OBJ_LAST_FIELD bpf_fd
736 static int bpf_obj_pin(const union bpf_attr *attr)
738 if (CHECK_ATTR(BPF_OBJ))
741 return bpf_obj_pin_user(attr->bpf_fd, u64_to_ptr(attr->pathname));
744 static int bpf_obj_get(const union bpf_attr *attr)
746 if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0)
749 return bpf_obj_get_user(u64_to_ptr(attr->pathname));
752 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
754 union bpf_attr attr = {};
757 if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled)
760 if (!access_ok(VERIFY_READ, uattr, 1))
763 if (size > PAGE_SIZE) /* silly large */
766 /* If we're handed a bigger struct than we know of,
767 * ensure all the unknown bits are 0 - i.e. new
768 * user-space does not rely on any kernel feature
769 * extensions we dont know about yet.
771 if (size > sizeof(attr)) {
772 unsigned char __user *addr;
773 unsigned char __user *end;
776 addr = (void __user *)uattr + sizeof(attr);
777 end = (void __user *)uattr + size;
779 for (; addr < end; addr++) {
780 err = get_user(val, addr);
789 /* copy attributes from user space, may be less than sizeof(bpf_attr) */
790 if (copy_from_user(&attr, uattr, size) != 0)
795 err = map_create(&attr);
797 case BPF_MAP_LOOKUP_ELEM:
798 err = map_lookup_elem(&attr);
800 case BPF_MAP_UPDATE_ELEM:
801 err = map_update_elem(&attr);
803 case BPF_MAP_DELETE_ELEM:
804 err = map_delete_elem(&attr);
806 case BPF_MAP_GET_NEXT_KEY:
807 err = map_get_next_key(&attr);
810 err = bpf_prog_load(&attr);
813 err = bpf_obj_pin(&attr);
816 err = bpf_obj_get(&attr);