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![Brenden Blanco](/assets/img/avatar_default.png)
A subsystem may need to store many copies of a bpf program, each deserving its own reference. Rather than requiring the caller to loop one by one (with possible mid-loop failure), add a bulk bpf_prog_add api. Signed-off-by: Brenden Blanco <bblanco@plumgrid.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
897 lines
20 KiB
C
897 lines
20 KiB
C
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/bpf.h>
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#include <linux/syscalls.h>
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#include <linux/slab.h>
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#include <linux/anon_inodes.h>
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#include <linux/file.h>
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#include <linux/license.h>
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#include <linux/filter.h>
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#include <linux/version.h>
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DEFINE_PER_CPU(int, bpf_prog_active);
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int sysctl_unprivileged_bpf_disabled __read_mostly;
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static LIST_HEAD(bpf_map_types);
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static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
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{
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struct bpf_map_type_list *tl;
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struct bpf_map *map;
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list_for_each_entry(tl, &bpf_map_types, list_node) {
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if (tl->type == attr->map_type) {
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map = tl->ops->map_alloc(attr);
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if (IS_ERR(map))
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return map;
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map->ops = tl->ops;
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map->map_type = attr->map_type;
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return map;
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}
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}
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return ERR_PTR(-EINVAL);
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}
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/* boot time registration of different map implementations */
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void bpf_register_map_type(struct bpf_map_type_list *tl)
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{
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list_add(&tl->list_node, &bpf_map_types);
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}
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int bpf_map_precharge_memlock(u32 pages)
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{
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struct user_struct *user = get_current_user();
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unsigned long memlock_limit, cur;
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memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
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cur = atomic_long_read(&user->locked_vm);
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free_uid(user);
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if (cur + pages > memlock_limit)
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return -EPERM;
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return 0;
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}
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static int bpf_map_charge_memlock(struct bpf_map *map)
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{
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struct user_struct *user = get_current_user();
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unsigned long memlock_limit;
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memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
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atomic_long_add(map->pages, &user->locked_vm);
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if (atomic_long_read(&user->locked_vm) > memlock_limit) {
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atomic_long_sub(map->pages, &user->locked_vm);
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free_uid(user);
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return -EPERM;
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}
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map->user = user;
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return 0;
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}
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static void bpf_map_uncharge_memlock(struct bpf_map *map)
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{
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struct user_struct *user = map->user;
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atomic_long_sub(map->pages, &user->locked_vm);
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free_uid(user);
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}
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/* called from workqueue */
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static void bpf_map_free_deferred(struct work_struct *work)
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{
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struct bpf_map *map = container_of(work, struct bpf_map, work);
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bpf_map_uncharge_memlock(map);
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/* implementation dependent freeing */
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map->ops->map_free(map);
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}
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static void bpf_map_put_uref(struct bpf_map *map)
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{
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if (atomic_dec_and_test(&map->usercnt)) {
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if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY)
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bpf_fd_array_map_clear(map);
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}
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}
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/* decrement map refcnt and schedule it for freeing via workqueue
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* (unrelying map implementation ops->map_free() might sleep)
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*/
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void bpf_map_put(struct bpf_map *map)
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{
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if (atomic_dec_and_test(&map->refcnt)) {
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INIT_WORK(&map->work, bpf_map_free_deferred);
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schedule_work(&map->work);
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}
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}
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void bpf_map_put_with_uref(struct bpf_map *map)
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{
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bpf_map_put_uref(map);
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bpf_map_put(map);
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}
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static int bpf_map_release(struct inode *inode, struct file *filp)
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{
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struct bpf_map *map = filp->private_data;
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if (map->ops->map_release)
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map->ops->map_release(map, filp);
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bpf_map_put_with_uref(map);
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return 0;
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}
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#ifdef CONFIG_PROC_FS
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static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
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{
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const struct bpf_map *map = filp->private_data;
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seq_printf(m,
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"map_type:\t%u\n"
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"key_size:\t%u\n"
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"value_size:\t%u\n"
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"max_entries:\t%u\n"
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"map_flags:\t%#x\n",
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map->map_type,
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map->key_size,
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map->value_size,
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map->max_entries,
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map->map_flags);
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}
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#endif
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static const struct file_operations bpf_map_fops = {
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#ifdef CONFIG_PROC_FS
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.show_fdinfo = bpf_map_show_fdinfo,
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#endif
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.release = bpf_map_release,
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};
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int bpf_map_new_fd(struct bpf_map *map)
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{
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return anon_inode_getfd("bpf-map", &bpf_map_fops, map,
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O_RDWR | O_CLOEXEC);
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}
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/* helper macro to check that unused fields 'union bpf_attr' are zero */
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#define CHECK_ATTR(CMD) \
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memchr_inv((void *) &attr->CMD##_LAST_FIELD + \
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sizeof(attr->CMD##_LAST_FIELD), 0, \
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sizeof(*attr) - \
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offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
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sizeof(attr->CMD##_LAST_FIELD)) != NULL
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#define BPF_MAP_CREATE_LAST_FIELD map_flags
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/* called via syscall */
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static int map_create(union bpf_attr *attr)
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{
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struct bpf_map *map;
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int err;
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err = CHECK_ATTR(BPF_MAP_CREATE);
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if (err)
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return -EINVAL;
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/* find map type and init map: hashtable vs rbtree vs bloom vs ... */
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map = find_and_alloc_map(attr);
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if (IS_ERR(map))
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return PTR_ERR(map);
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atomic_set(&map->refcnt, 1);
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atomic_set(&map->usercnt, 1);
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err = bpf_map_charge_memlock(map);
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if (err)
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goto free_map;
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err = bpf_map_new_fd(map);
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if (err < 0)
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/* failed to allocate fd */
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goto free_map;
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return err;
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free_map:
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map->ops->map_free(map);
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return err;
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}
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/* if error is returned, fd is released.
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* On success caller should complete fd access with matching fdput()
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*/
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struct bpf_map *__bpf_map_get(struct fd f)
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{
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if (!f.file)
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return ERR_PTR(-EBADF);
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if (f.file->f_op != &bpf_map_fops) {
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fdput(f);
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return ERR_PTR(-EINVAL);
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}
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return f.file->private_data;
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}
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/* prog's and map's refcnt limit */
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#define BPF_MAX_REFCNT 32768
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struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref)
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{
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if (atomic_inc_return(&map->refcnt) > BPF_MAX_REFCNT) {
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atomic_dec(&map->refcnt);
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return ERR_PTR(-EBUSY);
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}
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if (uref)
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atomic_inc(&map->usercnt);
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return map;
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}
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struct bpf_map *bpf_map_get_with_uref(u32 ufd)
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{
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struct fd f = fdget(ufd);
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struct bpf_map *map;
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map = __bpf_map_get(f);
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if (IS_ERR(map))
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return map;
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map = bpf_map_inc(map, true);
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fdput(f);
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return map;
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}
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/* helper to convert user pointers passed inside __aligned_u64 fields */
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static void __user *u64_to_ptr(__u64 val)
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{
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return (void __user *) (unsigned long) val;
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}
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int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
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{
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return -ENOTSUPP;
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}
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/* last field in 'union bpf_attr' used by this command */
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#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
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static int map_lookup_elem(union bpf_attr *attr)
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{
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void __user *ukey = u64_to_ptr(attr->key);
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void __user *uvalue = u64_to_ptr(attr->value);
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int ufd = attr->map_fd;
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struct bpf_map *map;
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void *key, *value, *ptr;
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u32 value_size;
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struct fd f;
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int err;
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if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
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return -EINVAL;
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f = fdget(ufd);
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map = __bpf_map_get(f);
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if (IS_ERR(map))
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return PTR_ERR(map);
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err = -ENOMEM;
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key = kmalloc(map->key_size, GFP_USER);
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if (!key)
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goto err_put;
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err = -EFAULT;
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if (copy_from_user(key, ukey, map->key_size) != 0)
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goto free_key;
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if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
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map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
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value_size = round_up(map->value_size, 8) * num_possible_cpus();
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else
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value_size = map->value_size;
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err = -ENOMEM;
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value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
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if (!value)
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goto free_key;
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if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
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err = bpf_percpu_hash_copy(map, key, value);
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} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
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err = bpf_percpu_array_copy(map, key, value);
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} else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
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err = bpf_stackmap_copy(map, key, value);
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} else {
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rcu_read_lock();
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ptr = map->ops->map_lookup_elem(map, key);
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if (ptr)
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memcpy(value, ptr, value_size);
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rcu_read_unlock();
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err = ptr ? 0 : -ENOENT;
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}
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if (err)
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goto free_value;
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err = -EFAULT;
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if (copy_to_user(uvalue, value, value_size) != 0)
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goto free_value;
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err = 0;
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free_value:
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kfree(value);
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free_key:
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kfree(key);
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err_put:
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fdput(f);
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return err;
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}
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#define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
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static int map_update_elem(union bpf_attr *attr)
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{
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void __user *ukey = u64_to_ptr(attr->key);
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void __user *uvalue = u64_to_ptr(attr->value);
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int ufd = attr->map_fd;
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struct bpf_map *map;
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void *key, *value;
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u32 value_size;
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struct fd f;
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int err;
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if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM))
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return -EINVAL;
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f = fdget(ufd);
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map = __bpf_map_get(f);
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if (IS_ERR(map))
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return PTR_ERR(map);
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err = -ENOMEM;
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key = kmalloc(map->key_size, GFP_USER);
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if (!key)
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goto err_put;
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err = -EFAULT;
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if (copy_from_user(key, ukey, map->key_size) != 0)
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goto free_key;
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if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
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map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
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value_size = round_up(map->value_size, 8) * num_possible_cpus();
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else
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value_size = map->value_size;
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err = -ENOMEM;
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value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
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if (!value)
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goto free_key;
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err = -EFAULT;
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if (copy_from_user(value, uvalue, value_size) != 0)
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goto free_value;
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/* must increment bpf_prog_active to avoid kprobe+bpf triggering from
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* inside bpf map update or delete otherwise deadlocks are possible
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*/
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preempt_disable();
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__this_cpu_inc(bpf_prog_active);
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if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
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err = bpf_percpu_hash_update(map, key, value, attr->flags);
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} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
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err = bpf_percpu_array_update(map, key, value, attr->flags);
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} else if (map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY ||
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map->map_type == BPF_MAP_TYPE_PROG_ARRAY ||
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map->map_type == BPF_MAP_TYPE_CGROUP_ARRAY) {
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rcu_read_lock();
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err = bpf_fd_array_map_update_elem(map, f.file, key, value,
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attr->flags);
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rcu_read_unlock();
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} else {
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rcu_read_lock();
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err = map->ops->map_update_elem(map, key, value, attr->flags);
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rcu_read_unlock();
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}
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__this_cpu_dec(bpf_prog_active);
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preempt_enable();
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free_value:
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kfree(value);
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free_key:
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kfree(key);
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err_put:
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fdput(f);
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return err;
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}
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#define BPF_MAP_DELETE_ELEM_LAST_FIELD key
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static int map_delete_elem(union bpf_attr *attr)
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{
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void __user *ukey = u64_to_ptr(attr->key);
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int ufd = attr->map_fd;
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struct bpf_map *map;
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struct fd f;
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void *key;
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int err;
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if (CHECK_ATTR(BPF_MAP_DELETE_ELEM))
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return -EINVAL;
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f = fdget(ufd);
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map = __bpf_map_get(f);
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if (IS_ERR(map))
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return PTR_ERR(map);
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err = -ENOMEM;
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key = kmalloc(map->key_size, GFP_USER);
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if (!key)
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goto err_put;
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err = -EFAULT;
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if (copy_from_user(key, ukey, map->key_size) != 0)
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goto free_key;
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preempt_disable();
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__this_cpu_inc(bpf_prog_active);
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rcu_read_lock();
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err = map->ops->map_delete_elem(map, key);
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rcu_read_unlock();
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__this_cpu_dec(bpf_prog_active);
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preempt_enable();
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free_key:
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kfree(key);
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err_put:
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fdput(f);
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return err;
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}
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/* last field in 'union bpf_attr' used by this command */
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#define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key
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static int map_get_next_key(union bpf_attr *attr)
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{
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void __user *ukey = u64_to_ptr(attr->key);
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void __user *unext_key = u64_to_ptr(attr->next_key);
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int ufd = attr->map_fd;
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struct bpf_map *map;
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void *key, *next_key;
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struct fd f;
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int err;
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if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY))
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return -EINVAL;
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f = fdget(ufd);
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map = __bpf_map_get(f);
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if (IS_ERR(map))
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return PTR_ERR(map);
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err = -ENOMEM;
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key = kmalloc(map->key_size, GFP_USER);
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if (!key)
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goto err_put;
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err = -EFAULT;
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if (copy_from_user(key, ukey, map->key_size) != 0)
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goto free_key;
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err = -ENOMEM;
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next_key = kmalloc(map->key_size, GFP_USER);
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if (!next_key)
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goto free_key;
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rcu_read_lock();
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err = map->ops->map_get_next_key(map, key, next_key);
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rcu_read_unlock();
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if (err)
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goto free_next_key;
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err = -EFAULT;
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if (copy_to_user(unext_key, next_key, map->key_size) != 0)
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goto free_next_key;
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err = 0;
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free_next_key:
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kfree(next_key);
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free_key:
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kfree(key);
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err_put:
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fdput(f);
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return err;
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}
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|
|
static LIST_HEAD(bpf_prog_types);
|
|
|
|
static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
|
|
{
|
|
struct bpf_prog_type_list *tl;
|
|
|
|
list_for_each_entry(tl, &bpf_prog_types, list_node) {
|
|
if (tl->type == type) {
|
|
prog->aux->ops = tl->ops;
|
|
prog->type = type;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
void bpf_register_prog_type(struct bpf_prog_type_list *tl)
|
|
{
|
|
list_add(&tl->list_node, &bpf_prog_types);
|
|
}
|
|
|
|
/* fixup insn->imm field of bpf_call instructions:
|
|
* if (insn->imm == BPF_FUNC_map_lookup_elem)
|
|
* insn->imm = bpf_map_lookup_elem - __bpf_call_base;
|
|
* else if (insn->imm == BPF_FUNC_map_update_elem)
|
|
* insn->imm = bpf_map_update_elem - __bpf_call_base;
|
|
* else ...
|
|
*
|
|
* this function is called after eBPF program passed verification
|
|
*/
|
|
static void fixup_bpf_calls(struct bpf_prog *prog)
|
|
{
|
|
const struct bpf_func_proto *fn;
|
|
int i;
|
|
|
|
for (i = 0; i < prog->len; i++) {
|
|
struct bpf_insn *insn = &prog->insnsi[i];
|
|
|
|
if (insn->code == (BPF_JMP | BPF_CALL)) {
|
|
/* we reach here when program has bpf_call instructions
|
|
* and it passed bpf_check(), means that
|
|
* ops->get_func_proto must have been supplied, check it
|
|
*/
|
|
BUG_ON(!prog->aux->ops->get_func_proto);
|
|
|
|
if (insn->imm == BPF_FUNC_get_route_realm)
|
|
prog->dst_needed = 1;
|
|
if (insn->imm == BPF_FUNC_get_prandom_u32)
|
|
bpf_user_rnd_init_once();
|
|
if (insn->imm == BPF_FUNC_tail_call) {
|
|
/* mark bpf_tail_call as different opcode
|
|
* to avoid conditional branch in
|
|
* interpeter for every normal call
|
|
* and to prevent accidental JITing by
|
|
* JIT compiler that doesn't support
|
|
* bpf_tail_call yet
|
|
*/
|
|
insn->imm = 0;
|
|
insn->code |= BPF_X;
|
|
continue;
|
|
}
|
|
|
|
fn = prog->aux->ops->get_func_proto(insn->imm);
|
|
/* all functions that have prototype and verifier allowed
|
|
* programs to call them, must be real in-kernel functions
|
|
*/
|
|
BUG_ON(!fn->func);
|
|
insn->imm = fn->func - __bpf_call_base;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* drop refcnt on maps used by eBPF program and free auxilary data */
|
|
static void free_used_maps(struct bpf_prog_aux *aux)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < aux->used_map_cnt; i++)
|
|
bpf_map_put(aux->used_maps[i]);
|
|
|
|
kfree(aux->used_maps);
|
|
}
|
|
|
|
static int bpf_prog_charge_memlock(struct bpf_prog *prog)
|
|
{
|
|
struct user_struct *user = get_current_user();
|
|
unsigned long memlock_limit;
|
|
|
|
memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
|
|
|
|
atomic_long_add(prog->pages, &user->locked_vm);
|
|
if (atomic_long_read(&user->locked_vm) > memlock_limit) {
|
|
atomic_long_sub(prog->pages, &user->locked_vm);
|
|
free_uid(user);
|
|
return -EPERM;
|
|
}
|
|
prog->aux->user = user;
|
|
return 0;
|
|
}
|
|
|
|
static void bpf_prog_uncharge_memlock(struct bpf_prog *prog)
|
|
{
|
|
struct user_struct *user = prog->aux->user;
|
|
|
|
atomic_long_sub(prog->pages, &user->locked_vm);
|
|
free_uid(user);
|
|
}
|
|
|
|
static void __bpf_prog_put_rcu(struct rcu_head *rcu)
|
|
{
|
|
struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
|
|
|
|
free_used_maps(aux);
|
|
bpf_prog_uncharge_memlock(aux->prog);
|
|
bpf_prog_free(aux->prog);
|
|
}
|
|
|
|
void bpf_prog_put(struct bpf_prog *prog)
|
|
{
|
|
if (atomic_dec_and_test(&prog->aux->refcnt))
|
|
call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_put);
|
|
|
|
static int bpf_prog_release(struct inode *inode, struct file *filp)
|
|
{
|
|
struct bpf_prog *prog = filp->private_data;
|
|
|
|
bpf_prog_put(prog);
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations bpf_prog_fops = {
|
|
.release = bpf_prog_release,
|
|
};
|
|
|
|
int bpf_prog_new_fd(struct bpf_prog *prog)
|
|
{
|
|
return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog,
|
|
O_RDWR | O_CLOEXEC);
|
|
}
|
|
|
|
static struct bpf_prog *____bpf_prog_get(struct fd f)
|
|
{
|
|
if (!f.file)
|
|
return ERR_PTR(-EBADF);
|
|
if (f.file->f_op != &bpf_prog_fops) {
|
|
fdput(f);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
return f.file->private_data;
|
|
}
|
|
|
|
struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i)
|
|
{
|
|
if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) {
|
|
atomic_sub(i, &prog->aux->refcnt);
|
|
return ERR_PTR(-EBUSY);
|
|
}
|
|
return prog;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_add);
|
|
|
|
struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
|
|
{
|
|
return bpf_prog_add(prog, 1);
|
|
}
|
|
|
|
static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type)
|
|
{
|
|
struct fd f = fdget(ufd);
|
|
struct bpf_prog *prog;
|
|
|
|
prog = ____bpf_prog_get(f);
|
|
if (IS_ERR(prog))
|
|
return prog;
|
|
if (type && prog->type != *type) {
|
|
prog = ERR_PTR(-EINVAL);
|
|
goto out;
|
|
}
|
|
|
|
prog = bpf_prog_inc(prog);
|
|
out:
|
|
fdput(f);
|
|
return prog;
|
|
}
|
|
|
|
struct bpf_prog *bpf_prog_get(u32 ufd)
|
|
{
|
|
return __bpf_prog_get(ufd, NULL);
|
|
}
|
|
|
|
struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type)
|
|
{
|
|
return __bpf_prog_get(ufd, &type);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bpf_prog_get_type);
|
|
|
|
/* last field in 'union bpf_attr' used by this command */
|
|
#define BPF_PROG_LOAD_LAST_FIELD kern_version
|
|
|
|
static int bpf_prog_load(union bpf_attr *attr)
|
|
{
|
|
enum bpf_prog_type type = attr->prog_type;
|
|
struct bpf_prog *prog;
|
|
int err;
|
|
char license[128];
|
|
bool is_gpl;
|
|
|
|
if (CHECK_ATTR(BPF_PROG_LOAD))
|
|
return -EINVAL;
|
|
|
|
/* copy eBPF program license from user space */
|
|
if (strncpy_from_user(license, u64_to_ptr(attr->license),
|
|
sizeof(license) - 1) < 0)
|
|
return -EFAULT;
|
|
license[sizeof(license) - 1] = 0;
|
|
|
|
/* eBPF programs must be GPL compatible to use GPL-ed functions */
|
|
is_gpl = license_is_gpl_compatible(license);
|
|
|
|
if (attr->insn_cnt >= BPF_MAXINSNS)
|
|
return -EINVAL;
|
|
|
|
if (type == BPF_PROG_TYPE_KPROBE &&
|
|
attr->kern_version != LINUX_VERSION_CODE)
|
|
return -EINVAL;
|
|
|
|
if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
/* plain bpf_prog allocation */
|
|
prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
|
|
if (!prog)
|
|
return -ENOMEM;
|
|
|
|
err = bpf_prog_charge_memlock(prog);
|
|
if (err)
|
|
goto free_prog_nouncharge;
|
|
|
|
prog->len = attr->insn_cnt;
|
|
|
|
err = -EFAULT;
|
|
if (copy_from_user(prog->insns, u64_to_ptr(attr->insns),
|
|
prog->len * sizeof(struct bpf_insn)) != 0)
|
|
goto free_prog;
|
|
|
|
prog->orig_prog = NULL;
|
|
prog->jited = 0;
|
|
|
|
atomic_set(&prog->aux->refcnt, 1);
|
|
prog->gpl_compatible = is_gpl ? 1 : 0;
|
|
|
|
/* find program type: socket_filter vs tracing_filter */
|
|
err = find_prog_type(type, prog);
|
|
if (err < 0)
|
|
goto free_prog;
|
|
|
|
/* run eBPF verifier */
|
|
err = bpf_check(&prog, attr);
|
|
if (err < 0)
|
|
goto free_used_maps;
|
|
|
|
/* fixup BPF_CALL->imm field */
|
|
fixup_bpf_calls(prog);
|
|
|
|
/* eBPF program is ready to be JITed */
|
|
prog = bpf_prog_select_runtime(prog, &err);
|
|
if (err < 0)
|
|
goto free_used_maps;
|
|
|
|
err = bpf_prog_new_fd(prog);
|
|
if (err < 0)
|
|
/* failed to allocate fd */
|
|
goto free_used_maps;
|
|
|
|
return err;
|
|
|
|
free_used_maps:
|
|
free_used_maps(prog->aux);
|
|
free_prog:
|
|
bpf_prog_uncharge_memlock(prog);
|
|
free_prog_nouncharge:
|
|
bpf_prog_free(prog);
|
|
return err;
|
|
}
|
|
|
|
#define BPF_OBJ_LAST_FIELD bpf_fd
|
|
|
|
static int bpf_obj_pin(const union bpf_attr *attr)
|
|
{
|
|
if (CHECK_ATTR(BPF_OBJ))
|
|
return -EINVAL;
|
|
|
|
return bpf_obj_pin_user(attr->bpf_fd, u64_to_ptr(attr->pathname));
|
|
}
|
|
|
|
static int bpf_obj_get(const union bpf_attr *attr)
|
|
{
|
|
if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0)
|
|
return -EINVAL;
|
|
|
|
return bpf_obj_get_user(u64_to_ptr(attr->pathname));
|
|
}
|
|
|
|
SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
|
|
{
|
|
union bpf_attr attr = {};
|
|
int err;
|
|
|
|
if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled)
|
|
return -EPERM;
|
|
|
|
if (!access_ok(VERIFY_READ, uattr, 1))
|
|
return -EFAULT;
|
|
|
|
if (size > PAGE_SIZE) /* silly large */
|
|
return -E2BIG;
|
|
|
|
/* If we're handed a bigger struct than we know of,
|
|
* ensure all the unknown bits are 0 - i.e. new
|
|
* user-space does not rely on any kernel feature
|
|
* extensions we dont know about yet.
|
|
*/
|
|
if (size > sizeof(attr)) {
|
|
unsigned char __user *addr;
|
|
unsigned char __user *end;
|
|
unsigned char val;
|
|
|
|
addr = (void __user *)uattr + sizeof(attr);
|
|
end = (void __user *)uattr + size;
|
|
|
|
for (; addr < end; addr++) {
|
|
err = get_user(val, addr);
|
|
if (err)
|
|
return err;
|
|
if (val)
|
|
return -E2BIG;
|
|
}
|
|
size = sizeof(attr);
|
|
}
|
|
|
|
/* copy attributes from user space, may be less than sizeof(bpf_attr) */
|
|
if (copy_from_user(&attr, uattr, size) != 0)
|
|
return -EFAULT;
|
|
|
|
switch (cmd) {
|
|
case BPF_MAP_CREATE:
|
|
err = map_create(&attr);
|
|
break;
|
|
case BPF_MAP_LOOKUP_ELEM:
|
|
err = map_lookup_elem(&attr);
|
|
break;
|
|
case BPF_MAP_UPDATE_ELEM:
|
|
err = map_update_elem(&attr);
|
|
break;
|
|
case BPF_MAP_DELETE_ELEM:
|
|
err = map_delete_elem(&attr);
|
|
break;
|
|
case BPF_MAP_GET_NEXT_KEY:
|
|
err = map_get_next_key(&attr);
|
|
break;
|
|
case BPF_PROG_LOAD:
|
|
err = bpf_prog_load(&attr);
|
|
break;
|
|
case BPF_OBJ_PIN:
|
|
err = bpf_obj_pin(&attr);
|
|
break;
|
|
case BPF_OBJ_GET:
|
|
err = bpf_obj_get(&attr);
|
|
break;
|
|
default:
|
|
err = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
return err;
|
|
}
|