kernel_optimize_test/kernel/bpf/arraymap.c
Alexei Starovoitov 823707b68d bpf: check for reserved flag bits in array and stack maps
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-08 15:28:31 -05:00

494 lines
12 KiB
C

/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/bpf.h>
#include <linux/err.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/filter.h>
#include <linux/perf_event.h>
static void bpf_array_free_percpu(struct bpf_array *array)
{
int i;
for (i = 0; i < array->map.max_entries; i++)
free_percpu(array->pptrs[i]);
}
static int bpf_array_alloc_percpu(struct bpf_array *array)
{
void __percpu *ptr;
int i;
for (i = 0; i < array->map.max_entries; i++) {
ptr = __alloc_percpu_gfp(array->elem_size, 8,
GFP_USER | __GFP_NOWARN);
if (!ptr) {
bpf_array_free_percpu(array);
return -ENOMEM;
}
array->pptrs[i] = ptr;
}
return 0;
}
/* Called from syscall */
static struct bpf_map *array_map_alloc(union bpf_attr *attr)
{
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
struct bpf_array *array;
u64 array_size;
u32 elem_size;
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
attr->value_size == 0 || attr->map_flags)
return ERR_PTR(-EINVAL);
if (attr->value_size >= 1 << (KMALLOC_SHIFT_MAX - 1))
/* if value_size is bigger, the user space won't be able to
* access the elements.
*/
return ERR_PTR(-E2BIG);
elem_size = round_up(attr->value_size, 8);
array_size = sizeof(*array);
if (percpu)
array_size += (u64) attr->max_entries * sizeof(void *);
else
array_size += (u64) attr->max_entries * elem_size;
/* make sure there is no u32 overflow later in round_up() */
if (array_size >= U32_MAX - PAGE_SIZE)
return ERR_PTR(-ENOMEM);
/* allocate all map elements and zero-initialize them */
array = kzalloc(array_size, GFP_USER | __GFP_NOWARN);
if (!array) {
array = vzalloc(array_size);
if (!array)
return ERR_PTR(-ENOMEM);
}
/* copy mandatory map attributes */
array->map.map_type = attr->map_type;
array->map.key_size = attr->key_size;
array->map.value_size = attr->value_size;
array->map.max_entries = attr->max_entries;
array->elem_size = elem_size;
if (!percpu)
goto out;
array_size += (u64) attr->max_entries * elem_size * num_possible_cpus();
if (array_size >= U32_MAX - PAGE_SIZE ||
elem_size > PCPU_MIN_UNIT_SIZE || bpf_array_alloc_percpu(array)) {
kvfree(array);
return ERR_PTR(-ENOMEM);
}
out:
array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
return &array->map;
}
/* Called from syscall or from eBPF program */
static void *array_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
if (unlikely(index >= array->map.max_entries))
return NULL;
return array->value + array->elem_size * index;
}
/* Called from eBPF program */
static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
if (unlikely(index >= array->map.max_entries))
return NULL;
return this_cpu_ptr(array->pptrs[index]);
}
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
void __percpu *pptr;
int cpu, off = 0;
u32 size;
if (unlikely(index >= array->map.max_entries))
return -ENOENT;
/* per_cpu areas are zero-filled and bpf programs can only
* access 'value_size' of them, so copying rounded areas
* will not leak any kernel data
*/
size = round_up(map->value_size, 8);
rcu_read_lock();
pptr = array->pptrs[index];
for_each_possible_cpu(cpu) {
bpf_long_memcpy(value + off, per_cpu_ptr(pptr, cpu), size);
off += size;
}
rcu_read_unlock();
return 0;
}
/* Called from syscall */
static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
u32 *next = (u32 *)next_key;
if (index >= array->map.max_entries) {
*next = 0;
return 0;
}
if (index == array->map.max_entries - 1)
return -ENOENT;
*next = index + 1;
return 0;
}
/* Called from syscall or from eBPF program */
static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
u64 map_flags)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
if (unlikely(map_flags > BPF_EXIST))
/* unknown flags */
return -EINVAL;
if (unlikely(index >= array->map.max_entries))
/* all elements were pre-allocated, cannot insert a new one */
return -E2BIG;
if (unlikely(map_flags == BPF_NOEXIST))
/* all elements already exist */
return -EEXIST;
if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
memcpy(this_cpu_ptr(array->pptrs[index]),
value, map->value_size);
else
memcpy(array->value + array->elem_size * index,
value, map->value_size);
return 0;
}
int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
u64 map_flags)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
void __percpu *pptr;
int cpu, off = 0;
u32 size;
if (unlikely(map_flags > BPF_EXIST))
/* unknown flags */
return -EINVAL;
if (unlikely(index >= array->map.max_entries))
/* all elements were pre-allocated, cannot insert a new one */
return -E2BIG;
if (unlikely(map_flags == BPF_NOEXIST))
/* all elements already exist */
return -EEXIST;
/* the user space will provide round_up(value_size, 8) bytes that
* will be copied into per-cpu area. bpf programs can only access
* value_size of it. During lookup the same extra bytes will be
* returned or zeros which were zero-filled by percpu_alloc,
* so no kernel data leaks possible
*/
size = round_up(map->value_size, 8);
rcu_read_lock();
pptr = array->pptrs[index];
for_each_possible_cpu(cpu) {
bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value + off, size);
off += size;
}
rcu_read_unlock();
return 0;
}
/* Called from syscall or from eBPF program */
static int array_map_delete_elem(struct bpf_map *map, void *key)
{
return -EINVAL;
}
/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
static void array_map_free(struct bpf_map *map)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
/* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
* so the programs (can be more than one that used this map) were
* disconnected from events. Wait for outstanding programs to complete
* and free the array
*/
synchronize_rcu();
if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
bpf_array_free_percpu(array);
kvfree(array);
}
static const struct bpf_map_ops array_ops = {
.map_alloc = array_map_alloc,
.map_free = array_map_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = array_map_lookup_elem,
.map_update_elem = array_map_update_elem,
.map_delete_elem = array_map_delete_elem,
};
static struct bpf_map_type_list array_type __read_mostly = {
.ops = &array_ops,
.type = BPF_MAP_TYPE_ARRAY,
};
static const struct bpf_map_ops percpu_array_ops = {
.map_alloc = array_map_alloc,
.map_free = array_map_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = percpu_array_map_lookup_elem,
.map_update_elem = array_map_update_elem,
.map_delete_elem = array_map_delete_elem,
};
static struct bpf_map_type_list percpu_array_type __read_mostly = {
.ops = &percpu_array_ops,
.type = BPF_MAP_TYPE_PERCPU_ARRAY,
};
static int __init register_array_map(void)
{
bpf_register_map_type(&array_type);
bpf_register_map_type(&percpu_array_type);
return 0;
}
late_initcall(register_array_map);
static struct bpf_map *fd_array_map_alloc(union bpf_attr *attr)
{
/* only file descriptors can be stored in this type of map */
if (attr->value_size != sizeof(u32))
return ERR_PTR(-EINVAL);
return array_map_alloc(attr);
}
static void fd_array_map_free(struct bpf_map *map)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
int i;
synchronize_rcu();
/* make sure it's empty */
for (i = 0; i < array->map.max_entries; i++)
BUG_ON(array->ptrs[i] != NULL);
kvfree(array);
}
static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
{
return NULL;
}
/* only called from syscall */
static int fd_array_map_update_elem(struct bpf_map *map, void *key,
void *value, u64 map_flags)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
void *new_ptr, *old_ptr;
u32 index = *(u32 *)key, ufd;
if (map_flags != BPF_ANY)
return -EINVAL;
if (index >= array->map.max_entries)
return -E2BIG;
ufd = *(u32 *)value;
new_ptr = map->ops->map_fd_get_ptr(map, ufd);
if (IS_ERR(new_ptr))
return PTR_ERR(new_ptr);
old_ptr = xchg(array->ptrs + index, new_ptr);
if (old_ptr)
map->ops->map_fd_put_ptr(old_ptr);
return 0;
}
static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
void *old_ptr;
u32 index = *(u32 *)key;
if (index >= array->map.max_entries)
return -E2BIG;
old_ptr = xchg(array->ptrs + index, NULL);
if (old_ptr) {
map->ops->map_fd_put_ptr(old_ptr);
return 0;
} else {
return -ENOENT;
}
}
static void *prog_fd_array_get_ptr(struct bpf_map *map, int fd)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_prog *prog = bpf_prog_get(fd);
if (IS_ERR(prog))
return prog;
if (!bpf_prog_array_compatible(array, prog)) {
bpf_prog_put(prog);
return ERR_PTR(-EINVAL);
}
return prog;
}
static void prog_fd_array_put_ptr(void *ptr)
{
struct bpf_prog *prog = ptr;
bpf_prog_put_rcu(prog);
}
/* decrement refcnt of all bpf_progs that are stored in this map */
void bpf_fd_array_map_clear(struct bpf_map *map)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
int i;
for (i = 0; i < array->map.max_entries; i++)
fd_array_map_delete_elem(map, &i);
}
static const struct bpf_map_ops prog_array_ops = {
.map_alloc = fd_array_map_alloc,
.map_free = fd_array_map_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = fd_array_map_lookup_elem,
.map_update_elem = fd_array_map_update_elem,
.map_delete_elem = fd_array_map_delete_elem,
.map_fd_get_ptr = prog_fd_array_get_ptr,
.map_fd_put_ptr = prog_fd_array_put_ptr,
};
static struct bpf_map_type_list prog_array_type __read_mostly = {
.ops = &prog_array_ops,
.type = BPF_MAP_TYPE_PROG_ARRAY,
};
static int __init register_prog_array_map(void)
{
bpf_register_map_type(&prog_array_type);
return 0;
}
late_initcall(register_prog_array_map);
static void perf_event_array_map_free(struct bpf_map *map)
{
bpf_fd_array_map_clear(map);
fd_array_map_free(map);
}
static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
{
struct perf_event *event;
const struct perf_event_attr *attr;
struct file *file;
file = perf_event_get(fd);
if (IS_ERR(file))
return file;
event = file->private_data;
attr = perf_event_attrs(event);
if (IS_ERR(attr))
goto err;
if (attr->inherit)
goto err;
if (attr->type == PERF_TYPE_RAW)
return file;
if (attr->type == PERF_TYPE_HARDWARE)
return file;
if (attr->type == PERF_TYPE_SOFTWARE &&
attr->config == PERF_COUNT_SW_BPF_OUTPUT)
return file;
err:
fput(file);
return ERR_PTR(-EINVAL);
}
static void perf_event_fd_array_put_ptr(void *ptr)
{
fput((struct file *)ptr);
}
static const struct bpf_map_ops perf_event_array_ops = {
.map_alloc = fd_array_map_alloc,
.map_free = perf_event_array_map_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = fd_array_map_lookup_elem,
.map_update_elem = fd_array_map_update_elem,
.map_delete_elem = fd_array_map_delete_elem,
.map_fd_get_ptr = perf_event_fd_array_get_ptr,
.map_fd_put_ptr = perf_event_fd_array_put_ptr,
};
static struct bpf_map_type_list perf_event_array_type __read_mostly = {
.ops = &perf_event_array_ops,
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
};
static int __init register_perf_event_array_map(void)
{
bpf_register_map_type(&perf_event_array_type);
return 0;
}
late_initcall(register_perf_event_array_map);