blob: 832b2659e96e2761d57f533a595aedf94d1b2112 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
* Copyright (c) 2016,2017 Facebook
*/
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/filter.h>
#include <linux/perf_event.h>
#include <uapi/linux/btf.h>
#include <linux/rcupdate_trace.h>
#include <linux/btf_ids.h>
#include "map_in_map.h"
#define ARRAY_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
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]);
cond_resched();
}
}
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 = bpf_map_alloc_percpu(&array->map, array->elem_size, 8,
GFP_USER | __GFP_NOWARN);
if (!ptr) {
bpf_array_free_percpu(array);
return -ENOMEM;
}
array->pptrs[i] = ptr;
cond_resched();
}
return 0;
}
/* Called from syscall */
int array_map_alloc_check(union bpf_attr *attr)
{
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
int numa_node = bpf_map_attr_numa_node(attr);
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
attr->value_size == 0 ||
attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
!bpf_map_flags_access_ok(attr->map_flags) ||
(percpu && numa_node != NUMA_NO_NODE))
return -EINVAL;
if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
return -EINVAL;
if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
attr->map_flags & BPF_F_PRESERVE_ELEMS)
return -EINVAL;
/* avoid overflow on round_up(map->value_size) */
if (attr->value_size > INT_MAX)
return -E2BIG;
return 0;
}
static struct bpf_map *array_map_alloc(union bpf_attr *attr)
{
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
int numa_node = bpf_map_attr_numa_node(attr);
u32 elem_size, index_mask, max_entries;
bool bypass_spec_v1 = bpf_bypass_spec_v1();
u64 array_size, mask64;
struct bpf_array *array;
elem_size = round_up(attr->value_size, 8);
max_entries = attr->max_entries;
/* On 32 bit archs roundup_pow_of_two() with max_entries that has
* upper most bit set in u32 space is undefined behavior due to
* resulting 1U << 32, so do it manually here in u64 space.
*/
mask64 = fls_long(max_entries - 1);
mask64 = 1ULL << mask64;
mask64 -= 1;
index_mask = mask64;
if (!bypass_spec_v1) {
/* round up array size to nearest power of 2,
* since cpu will speculate within index_mask limits
*/
max_entries = index_mask + 1;
/* Check for overflows. */
if (max_entries < attr->max_entries)
return ERR_PTR(-E2BIG);
}
array_size = sizeof(*array);
if (percpu) {
array_size += (u64) max_entries * sizeof(void *);
} else {
/* rely on vmalloc() to return page-aligned memory and
* ensure array->value is exactly page-aligned
*/
if (attr->map_flags & BPF_F_MMAPABLE) {
array_size = PAGE_ALIGN(array_size);
array_size += PAGE_ALIGN((u64) max_entries * elem_size);
} else {
array_size += (u64) max_entries * elem_size;
}
}
/* allocate all map elements and zero-initialize them */
if (attr->map_flags & BPF_F_MMAPABLE) {
void *data;
/* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
data = bpf_map_area_mmapable_alloc(array_size, numa_node);
if (!data)
return ERR_PTR(-ENOMEM);
array = data + PAGE_ALIGN(sizeof(struct bpf_array))
- offsetof(struct bpf_array, value);
} else {
array = bpf_map_area_alloc(array_size, numa_node);
}
if (!array)
return ERR_PTR(-ENOMEM);
array->index_mask = index_mask;
array->map.bypass_spec_v1 = bypass_spec_v1;
/* copy mandatory map attributes */
bpf_map_init_from_attr(&array->map, attr);
array->elem_size = elem_size;
if (percpu && bpf_array_alloc_percpu(array)) {
bpf_map_area_free(array);
return ERR_PTR(-ENOMEM);
}
return &array->map;
}
static void *array_map_elem_ptr(struct bpf_array* array, u32 index)
{
return array->value + (u64)array->elem_size * index;
}
/* 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 + (u64)array->elem_size * (index & array->index_mask);
}
static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
u32 off)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
if (map->max_entries != 1)
return -ENOTSUPP;
if (off >= map->value_size)
return -EINVAL;
*imm = (unsigned long)array->value;
return 0;
}
static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
u32 *off)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u64 base = (unsigned long)array->value;
u64 range = array->elem_size;
if (map->max_entries != 1)
return -ENOTSUPP;
if (imm < base || imm >= base + range)
return -ENOENT;
*off = imm - base;
return 0;
}
/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_insn *insn = insn_buf;
u32 elem_size = array->elem_size;
const int ret = BPF_REG_0;
const int map_ptr = BPF_REG_1;
const int index = BPF_REG_2;
if (map->map_flags & BPF_F_INNER_MAP)
return -EOPNOTSUPP;
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
if (!map->bypass_spec_v1) {
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
} else {
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
}
if (is_power_of_2(elem_size)) {
*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
} else {
*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
}
*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
*insn++ = BPF_MOV64_IMM(ret, 0);
return insn - insn_buf;
}
/* 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 & array->index_mask]);
}
static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
if (cpu >= nr_cpu_ids)
return NULL;
if (unlikely(index >= array->map.max_entries))
return NULL;
return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
}
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 = array->elem_size;
rcu_read_lock();
pptr = array->pptrs[index & array->index_mask];
for_each_possible_cpu(cpu) {
copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
check_and_init_map_value(map, value + off);
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 = key ? *(u32 *)key : U32_MAX;
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;
}
static void check_and_free_fields(struct bpf_array *arr, void *val)
{
if (map_value_has_timer(&arr->map))
bpf_timer_cancel_and_free(val + arr->map.timer_off);
if (map_value_has_kptrs(&arr->map))
bpf_map_free_kptrs(&arr->map, val);
}
/* 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;
char *val;
if (unlikely((map_flags & ~BPF_F_LOCK) > 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 (unlikely((map_flags & BPF_F_LOCK) &&
!map_value_has_spin_lock(map)))
return -EINVAL;
if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
val = this_cpu_ptr(array->pptrs[index & array->index_mask]);
copy_map_value(map, val, value);
check_and_free_fields(array, val);
} else {
val = array->value +
(u64)array->elem_size * (index & array->index_mask);
if (map_flags & BPF_F_LOCK)
copy_map_value_locked(map, val, value, false);
else
copy_map_value(map, val, value);
check_and_free_fields(array, val);
}
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 = array->elem_size;
rcu_read_lock();
pptr = array->pptrs[index & array->index_mask];
for_each_possible_cpu(cpu) {
copy_map_value_long(map, per_cpu_ptr(pptr, cpu), value + off);
check_and_free_fields(array, per_cpu_ptr(pptr, cpu));
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;
}
static void *array_map_vmalloc_addr(struct bpf_array *array)
{
return (void *)round_down((unsigned long)array, PAGE_SIZE);
}
static void array_map_free_timers(struct bpf_map *map)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
int i;
/* We don't reset or free kptr on uref dropping to zero. */
if (!map_value_has_timer(map))
return;
for (i = 0; i < array->map.max_entries; i++)
bpf_timer_cancel_and_free(array_map_elem_ptr(array, i) + map->timer_off);
}
/* 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);
int i;
if (map_value_has_kptrs(map)) {
if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
for (i = 0; i < array->map.max_entries; i++) {
void __percpu *pptr = array->pptrs[i & array->index_mask];
int cpu;
for_each_possible_cpu(cpu) {
bpf_map_free_kptrs(map, per_cpu_ptr(pptr, cpu));
cond_resched();
}
}
} else {
for (i = 0; i < array->map.max_entries; i++)
bpf_map_free_kptrs(map, array_map_elem_ptr(array, i));
}
bpf_map_free_kptr_off_tab(map);
}
if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
bpf_array_free_percpu(array);
if (array->map.map_flags & BPF_F_MMAPABLE)
bpf_map_area_free(array_map_vmalloc_addr(array));
else
bpf_map_area_free(array);
}
static void array_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
void *value;
rcu_read_lock();
value = array_map_lookup_elem(map, key);
if (!value) {
rcu_read_unlock();
return;
}
if (map->btf_key_type_id)
seq_printf(m, "%u: ", *(u32 *)key);
btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
seq_puts(m, "\n");
rcu_read_unlock();
}
static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
void __percpu *pptr;
int cpu;
rcu_read_lock();
seq_printf(m, "%u: {\n", *(u32 *)key);
pptr = array->pptrs[index & array->index_mask];
for_each_possible_cpu(cpu) {
seq_printf(m, "\tcpu%d: ", cpu);
btf_type_seq_show(map->btf, map->btf_value_type_id,
per_cpu_ptr(pptr, cpu), m);
seq_puts(m, "\n");
}
seq_puts(m, "}\n");
rcu_read_unlock();
}
static int 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)
{
u32 int_data;
/* One exception for keyless BTF: .bss/.data/.rodata map */
if (btf_type_is_void(key_type)) {
if (map->map_type != BPF_MAP_TYPE_ARRAY ||
map->max_entries != 1)
return -EINVAL;
if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
return -EINVAL;
return 0;
}
if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
return -EINVAL;
int_data = *(u32 *)(key_type + 1);
/* bpf array can only take a u32 key. This check makes sure
* that the btf matches the attr used during map_create.
*/
if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
return -EINVAL;
return 0;
}
static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
if (!(map->map_flags & BPF_F_MMAPABLE))
return -EINVAL;
if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
return -EINVAL;
return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
vma->vm_pgoff + pgoff);
}
static bool array_map_meta_equal(const struct bpf_map *meta0,
const struct bpf_map *meta1)
{
if (!bpf_map_meta_equal(meta0, meta1))
return false;
return meta0->map_flags & BPF_F_INNER_MAP ? true :
meta0->max_entries == meta1->max_entries;
}
struct bpf_iter_seq_array_map_info {
struct bpf_map *map;
void *percpu_value_buf;
u32 index;
};
static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
{
struct bpf_iter_seq_array_map_info *info = seq->private;
struct bpf_map *map = info->map;
struct bpf_array *array;
u32 index;
if (info->index >= map->max_entries)
return NULL;
if (*pos == 0)
++*pos;
array = container_of(map, struct bpf_array, map);
index = info->index & array->index_mask;
if (info->percpu_value_buf)
return array->pptrs[index];
return array_map_elem_ptr(array, index);
}
static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct bpf_iter_seq_array_map_info *info = seq->private;
struct bpf_map *map = info->map;
struct bpf_array *array;
u32 index;
++*pos;
++info->index;
if (info->index >= map->max_entries)
return NULL;
array = container_of(map, struct bpf_array, map);
index = info->index & array->index_mask;
if (info->percpu_value_buf)
return array->pptrs[index];
return array_map_elem_ptr(array, index);
}
static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
{
struct bpf_iter_seq_array_map_info *info = seq->private;
struct bpf_iter__bpf_map_elem ctx = {};
struct bpf_map *map = info->map;
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_iter_meta meta;
struct bpf_prog *prog;
int off = 0, cpu = 0;
void __percpu **pptr;
u32 size;
meta.seq = seq;
prog = bpf_iter_get_info(&meta, v == NULL);
if (!prog)
return 0;
ctx.meta = &meta;
ctx.map = info->map;
if (v) {
ctx.key = &info->index;
if (!info->percpu_value_buf) {
ctx.value = v;
} else {
pptr = v;
size = array->elem_size;
for_each_possible_cpu(cpu) {
copy_map_value_long(map, info->percpu_value_buf + off,
per_cpu_ptr(pptr, cpu));
check_and_init_map_value(map, info->percpu_value_buf + off);
off += size;
}
ctx.value = info->percpu_value_buf;
}
}
return bpf_iter_run_prog(prog, &ctx);
}
static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
{
return __bpf_array_map_seq_show(seq, v);
}
static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
{
if (!v)
(void)__bpf_array_map_seq_show(seq, NULL);
}
static int bpf_iter_init_array_map(void *priv_data,
struct bpf_iter_aux_info *aux)
{
struct bpf_iter_seq_array_map_info *seq_info = priv_data;
struct bpf_map *map = aux->map;
struct bpf_array *array = container_of(map, struct bpf_array, map);
void *value_buf;
u32 buf_size;
if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
buf_size = array->elem_size * num_possible_cpus();
value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
if (!value_buf)
return -ENOMEM;
seq_info->percpu_value_buf = value_buf;
}
/* bpf_iter_attach_map() acquires a map uref, and the uref may be
* released before or in the middle of iterating map elements, so
* acquire an extra map uref for iterator.
*/
bpf_map_inc_with_uref(map);
seq_info->map = map;
return 0;
}
static void bpf_iter_fini_array_map(void *priv_data)
{
struct bpf_iter_seq_array_map_info *seq_info = priv_data;
bpf_map_put_with_uref(seq_info->map);
kfree(seq_info->percpu_value_buf);
}
static const struct seq_operations bpf_array_map_seq_ops = {
.start = bpf_array_map_seq_start,
.next = bpf_array_map_seq_next,
.stop = bpf_array_map_seq_stop,
.show = bpf_array_map_seq_show,
};
static const struct bpf_iter_seq_info iter_seq_info = {
.seq_ops = &bpf_array_map_seq_ops,
.init_seq_private = bpf_iter_init_array_map,
.fini_seq_private = bpf_iter_fini_array_map,
.seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
};
static int bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn,
void *callback_ctx, u64 flags)
{
u32 i, key, num_elems = 0;
struct bpf_array *array;
bool is_percpu;
u64 ret = 0;
void *val;
if (flags != 0)
return -EINVAL;
is_percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
array = container_of(map, struct bpf_array, map);
if (is_percpu)
migrate_disable();
for (i = 0; i < map->max_entries; i++) {
if (is_percpu)
val = this_cpu_ptr(array->pptrs[i]);
else
val = array_map_elem_ptr(array, i);
num_elems++;
key = i;
ret = callback_fn((u64)(long)map, (u64)(long)&key,
(u64)(long)val, (u64)(long)callback_ctx, 0);
/* return value: 0 - continue, 1 - stop and return */
if (ret)
break;
}
if (is_percpu)
migrate_enable();
return num_elems;
}
BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)
const struct bpf_map_ops array_map_ops = {
.map_meta_equal = array_map_meta_equal,
.map_alloc_check = array_map_alloc_check,
.map_alloc = array_map_alloc,
.map_free = array_map_free,
.map_get_next_key = array_map_get_next_key,
.map_release_uref = array_map_free_timers,
.map_lookup_elem = array_map_lookup_elem,
.map_update_elem = array_map_update_elem,
.map_delete_elem = array_map_delete_elem,
.map_gen_lookup = array_map_gen_lookup,
.map_direct_value_addr = array_map_direct_value_addr,
.map_direct_value_meta = array_map_direct_value_meta,
.map_mmap = array_map_mmap,
.map_seq_show_elem = array_map_seq_show_elem,
.map_check_btf = array_map_check_btf,
.map_lookup_batch = generic_map_lookup_batch,
.map_update_batch = generic_map_update_batch,
.map_set_for_each_callback_args = map_set_for_each_callback_args,
.map_for_each_callback = bpf_for_each_array_elem,
.map_btf_id = &array_map_btf_ids[0],
.iter_seq_info = &iter_seq_info,
};
const struct bpf_map_ops percpu_array_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = array_map_alloc_check,
.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,
.map_lookup_percpu_elem = percpu_array_map_lookup_percpu_elem,
.map_seq_show_elem = percpu_array_map_seq_show_elem,
.map_check_btf = array_map_check_btf,
.map_lookup_batch = generic_map_lookup_batch,
.map_update_batch = generic_map_update_batch,
.map_set_for_each_callback_args = map_set_for_each_callback_args,
.map_for_each_callback = bpf_for_each_array_elem,
.map_btf_id = &array_map_btf_ids[0],
.iter_seq_info = &iter_seq_info,
};
static int fd_array_map_alloc_check(union bpf_attr *attr)
{
/* only file descriptors can be stored in this type of map */
if (attr->value_size != sizeof(u32))
return -EINVAL;
/* Program read-only/write-only not supported for special maps yet. */
if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
return -EINVAL;
return array_map_alloc_check(attr);
}
static void fd_array_map_free(struct bpf_map *map)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
int i;
/* make sure it's empty */
for (i = 0; i < array->map.max_entries; i++)
BUG_ON(array->ptrs[i] != NULL);
bpf_map_area_free(array);
}
static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
{
return ERR_PTR(-EOPNOTSUPP);
}
/* only called from syscall */
int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
{
void **elem, *ptr;
int ret = 0;
if (!map->ops->map_fd_sys_lookup_elem)
return -ENOTSUPP;
rcu_read_lock();
elem = array_map_lookup_elem(map, key);
if (elem && (ptr = READ_ONCE(*elem)))
*value = map->ops->map_fd_sys_lookup_elem(ptr);
else
ret = -ENOENT;
rcu_read_unlock();
return ret;
}
/* only called from syscall */
int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
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, map_file, ufd);
if (IS_ERR(new_ptr))
return PTR_ERR(new_ptr);
if (map->ops->map_poke_run) {
mutex_lock(&array->aux->poke_mutex);
old_ptr = xchg(array->ptrs + index, new_ptr);
map->ops->map_poke_run(map, index, old_ptr, new_ptr);
mutex_unlock(&array->aux->poke_mutex);
} else {
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;
if (map->ops->map_poke_run) {
mutex_lock(&array->aux->poke_mutex);
old_ptr = xchg(array->ptrs + index, NULL);
map->ops->map_poke_run(map, index, old_ptr, NULL);
mutex_unlock(&array->aux->poke_mutex);
} else {
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,
struct file *map_file, int fd)
{
struct bpf_prog *prog = bpf_prog_get(fd);
if (IS_ERR(prog))
return prog;
if (!bpf_prog_map_compatible(map, prog)) {
bpf_prog_put(prog);
return ERR_PTR(-EINVAL);
}
return prog;
}
static void prog_fd_array_put_ptr(void *ptr)
{
bpf_prog_put(ptr);
}
static u32 prog_fd_array_sys_lookup_elem(void *ptr)
{
return ((struct bpf_prog *)ptr)->aux->id;
}
/* decrement refcnt of all bpf_progs that are stored in this map */
static 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 void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
void **elem, *ptr;
u32 prog_id;
rcu_read_lock();
elem = array_map_lookup_elem(map, key);
if (elem) {
ptr = READ_ONCE(*elem);
if (ptr) {
seq_printf(m, "%u: ", *(u32 *)key);
prog_id = prog_fd_array_sys_lookup_elem(ptr);
btf_type_seq_show(map->btf, map->btf_value_type_id,
&prog_id, m);
seq_puts(m, "\n");
}
}
rcu_read_unlock();
}
struct prog_poke_elem {
struct list_head list;
struct bpf_prog_aux *aux;
};
static int prog_array_map_poke_track(struct bpf_map *map,
struct bpf_prog_aux *prog_aux)
{
struct prog_poke_elem *elem;
struct bpf_array_aux *aux;
int ret = 0;
aux = container_of(map, struct bpf_array, map)->aux;
mutex_lock(&aux->poke_mutex);
list_for_each_entry(elem, &aux->poke_progs, list) {
if (elem->aux == prog_aux)
goto out;
}
elem = kmalloc(sizeof(*elem), GFP_KERNEL);
if (!elem) {
ret = -ENOMEM;
goto out;
}
INIT_LIST_HEAD(&elem->list);
/* We must track the program's aux info at this point in time
* since the program pointer itself may not be stable yet, see
* also comment in prog_array_map_poke_run().
*/
elem->aux = prog_aux;
list_add_tail(&elem->list, &aux->poke_progs);
out:
mutex_unlock(&aux->poke_mutex);
return ret;
}
static void prog_array_map_poke_untrack(struct bpf_map *map,
struct bpf_prog_aux *prog_aux)
{
struct prog_poke_elem *elem, *tmp;
struct bpf_array_aux *aux;
aux = container_of(map, struct bpf_array, map)->aux;
mutex_lock(&aux->poke_mutex);
list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
if (elem->aux == prog_aux) {
list_del_init(&elem->list);
kfree(elem);
break;
}
}
mutex_unlock(&aux->poke_mutex);
}
static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
struct bpf_prog *old,
struct bpf_prog *new)
{
u8 *old_addr, *new_addr, *old_bypass_addr;
struct prog_poke_elem *elem;
struct bpf_array_aux *aux;
aux = container_of(map, struct bpf_array, map)->aux;
WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
list_for_each_entry(elem, &aux->poke_progs, list) {
struct bpf_jit_poke_descriptor *poke;
int i, ret;
for (i = 0; i < elem->aux->size_poke_tab; i++) {
poke = &elem->aux->poke_tab[i];
/* Few things to be aware of:
*
* 1) We can only ever access aux in this context, but
* not aux->prog since it might not be stable yet and
* there could be danger of use after free otherwise.
* 2) Initially when we start tracking aux, the program
* is not JITed yet and also does not have a kallsyms
* entry. We skip these as poke->tailcall_target_stable
* is not active yet. The JIT will do the final fixup
* before setting it stable. The various
* poke->tailcall_target_stable are successively
* activated, so tail call updates can arrive from here
* while JIT is still finishing its final fixup for
* non-activated poke entries.
* 3) On program teardown, the program's kallsym entry gets
* removed out of RCU callback, but we can only untrack
* from sleepable context, therefore bpf_arch_text_poke()
* might not see that this is in BPF text section and
* bails out with -EINVAL. As these are unreachable since
* RCU grace period already passed, we simply skip them.
* 4) Also programs reaching refcount of zero while patching
* is in progress is okay since we're protected under
* poke_mutex and untrack the programs before the JIT
* buffer is freed. When we're still in the middle of
* patching and suddenly kallsyms entry of the program
* gets evicted, we just skip the rest which is fine due
* to point 3).
* 5) Any other error happening below from bpf_arch_text_poke()
* is a unexpected bug.
*/
if (!READ_ONCE(poke->tailcall_target_stable))
continue;
if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
continue;
if (poke->tail_call.map != map ||
poke->tail_call.key != key)
continue;
old_bypass_addr = old ? NULL : poke->bypass_addr;
old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
if (new) {
ret = bpf_arch_text_poke(poke->tailcall_target,
BPF_MOD_JUMP,
old_addr, new_addr);
BUG_ON(ret < 0 && ret != -EINVAL);
if (!old) {
ret = bpf_arch_text_poke(poke->tailcall_bypass,
BPF_MOD_JUMP,
poke->bypass_addr,
NULL);
BUG_ON(ret < 0 && ret != -EINVAL);
}
} else {
ret = bpf_arch_text_poke(poke->tailcall_bypass,
BPF_MOD_JUMP,
old_bypass_addr,
poke->bypass_addr);
BUG_ON(ret < 0 && ret != -EINVAL);
/* let other CPUs finish the execution of program
* so that it will not possible to expose them
* to invalid nop, stack unwind, nop state
*/
if (!ret)
synchronize_rcu();
ret = bpf_arch_text_poke(poke->tailcall_target,
BPF_MOD_JUMP,
old_addr, NULL);
BUG_ON(ret < 0 && ret != -EINVAL);
}
}
}
}
static void prog_array_map_clear_deferred(struct work_struct *work)
{
struct bpf_map *map = container_of(work, struct bpf_array_aux,
work)->map;
bpf_fd_array_map_clear(map);
bpf_map_put(map);
}
static void prog_array_map_clear(struct bpf_map *map)
{
struct bpf_array_aux *aux = container_of(map, struct bpf_array,
map)->aux;
bpf_map_inc(map);
schedule_work(&aux->work);
}
static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
{
struct bpf_array_aux *aux;
struct bpf_map *map;
aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT);
if (!aux)
return ERR_PTR(-ENOMEM);
INIT_WORK(&aux->work, prog_array_map_clear_deferred);
INIT_LIST_HEAD(&aux->poke_progs);
mutex_init(&aux->poke_mutex);
map = array_map_alloc(attr);
if (IS_ERR(map)) {
kfree(aux);
return map;
}
container_of(map, struct bpf_array, map)->aux = aux;
aux->map = map;
return map;
}
static void prog_array_map_free(struct bpf_map *map)
{
struct prog_poke_elem *elem, *tmp;
struct bpf_array_aux *aux;
aux = container_of(map, struct bpf_array, map)->aux;
list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
list_del_init(&elem->list);
kfree(elem);
}
kfree(aux);
fd_array_map_free(map);
}
/* prog_array->aux->{type,jited} is a runtime binding.
* Doing static check alone in the verifier is not enough.
* Thus, prog_array_map cannot be used as an inner_map
* and map_meta_equal is not implemented.
*/
const struct bpf_map_ops prog_array_map_ops = {
.map_alloc_check = fd_array_map_alloc_check,
.map_alloc = prog_array_map_alloc,
.map_free = prog_array_map_free,
.map_poke_track = prog_array_map_poke_track,
.map_poke_untrack = prog_array_map_poke_untrack,
.map_poke_run = prog_array_map_poke_run,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = fd_array_map_lookup_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,
.map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
.map_release_uref = prog_array_map_clear,
.map_seq_show_elem = prog_array_map_seq_show_elem,
.map_btf_id = &array_map_btf_ids[0],
};
static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
struct file *map_file)
{
struct bpf_event_entry *ee;
ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
if (ee) {
ee->event = perf_file->private_data;
ee->perf_file = perf_file;
ee->map_file = map_file;
}
return ee;
}
static void __bpf_event_entry_free(struct rcu_head *rcu)
{
struct bpf_event_entry *ee;
ee = container_of(rcu, struct bpf_event_entry, rcu);
fput(ee->perf_file);
kfree(ee);
}
static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
{
call_rcu(&ee->rcu, __bpf_event_entry_free);
}
static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
struct file *map_file, int fd)
{
struct bpf_event_entry *ee;
struct perf_event *event;
struct file *perf_file;
u64 value;
perf_file = perf_event_get(fd);
if (IS_ERR(perf_file))
return perf_file;
ee = ERR_PTR(-EOPNOTSUPP);
event = perf_file->private_data;
if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
goto err_out;
ee = bpf_event_entry_gen(perf_file, map_file);
if (ee)
return ee;
ee = ERR_PTR(-ENOMEM);
err_out:
fput(perf_file);
return ee;
}
static void perf_event_fd_array_put_ptr(void *ptr)
{
bpf_event_entry_free_rcu(ptr);
}
static void perf_event_fd_array_release(struct bpf_map *map,
struct file *map_file)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_event_entry *ee;
int i;
if (map->map_flags & BPF_F_PRESERVE_ELEMS)
return;
rcu_read_lock();
for (i = 0; i < array->map.max_entries; i++) {
ee = READ_ONCE(array->ptrs[i]);
if (ee && ee->map_file == map_file)
fd_array_map_delete_elem(map, &i);
}
rcu_read_unlock();
}
static void perf_event_fd_array_map_free(struct bpf_map *map)
{
if (map->map_flags & BPF_F_PRESERVE_ELEMS)
bpf_fd_array_map_clear(map);
fd_array_map_free(map);
}
const struct bpf_map_ops perf_event_array_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = fd_array_map_alloc_check,
.map_alloc = array_map_alloc,
.map_free = perf_event_fd_array_map_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = fd_array_map_lookup_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,
.map_release = perf_event_fd_array_release,
.map_check_btf = map_check_no_btf,
.map_btf_id = &array_map_btf_ids[0],
};
#ifdef CONFIG_CGROUPS
static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
struct file *map_file /* not used */,
int fd)
{
return cgroup_get_from_fd(fd);
}
static void cgroup_fd_array_put_ptr(void *ptr)
{
/* cgroup_put free cgrp after a rcu grace period */
cgroup_put(ptr);
}
static void cgroup_fd_array_free(struct bpf_map *map)
{
bpf_fd_array_map_clear(map);
fd_array_map_free(map);
}
const struct bpf_map_ops cgroup_array_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = fd_array_map_alloc_check,
.map_alloc = array_map_alloc,
.map_free = cgroup_fd_array_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = fd_array_map_lookup_elem,
.map_delete_elem = fd_array_map_delete_elem,
.map_fd_get_ptr = cgroup_fd_array_get_ptr,
.map_fd_put_ptr = cgroup_fd_array_put_ptr,
.map_check_btf = map_check_no_btf,
.map_btf_id = &array_map_btf_ids[0],
};
#endif
static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
{
struct bpf_map *map, *inner_map_meta;
inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
if (IS_ERR(inner_map_meta))
return inner_map_meta;
map = array_map_alloc(attr);
if (IS_ERR(map)) {
bpf_map_meta_free(inner_map_meta);
return map;
}
map->inner_map_meta = inner_map_meta;
return map;
}
static void array_of_map_free(struct bpf_map *map)
{
/* map->inner_map_meta is only accessed by syscall which
* is protected by fdget/fdput.
*/
bpf_map_meta_free(map->inner_map_meta);
bpf_fd_array_map_clear(map);
fd_array_map_free(map);
}
static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_map **inner_map = array_map_lookup_elem(map, key);
if (!inner_map)
return NULL;
return READ_ONCE(*inner_map);
}
static int array_of_map_gen_lookup(struct bpf_map *map,
struct bpf_insn *insn_buf)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 elem_size = array->elem_size;
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
const int map_ptr = BPF_REG_1;
const int index = BPF_REG_2;
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
if (!map->bypass_spec_v1) {
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
} else {
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
}
if (is_power_of_2(elem_size))
*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
else
*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
*insn++ = BPF_MOV64_IMM(ret, 0);
return insn - insn_buf;
}
const struct bpf_map_ops array_of_maps_map_ops = {
.map_alloc_check = fd_array_map_alloc_check,
.map_alloc = array_of_map_alloc,
.map_free = array_of_map_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = array_of_map_lookup_elem,
.map_delete_elem = fd_array_map_delete_elem,
.map_fd_get_ptr = bpf_map_fd_get_ptr,
.map_fd_put_ptr = bpf_map_fd_put_ptr,
.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
.map_gen_lookup = array_of_map_gen_lookup,
.map_lookup_batch = generic_map_lookup_batch,
.map_update_batch = generic_map_update_batch,
.map_check_btf = map_check_no_btf,
.map_btf_id = &array_map_btf_ids[0],
};