kernel_optimize_test/kernel/bpf/syscall.c
Daniel Borkmann 7bd509e311 bpf: add prog_digest and expose it via fdinfo/netlink
When loading a BPF program via bpf(2), calculate the digest over
the program's instruction stream and store it in struct bpf_prog's
digest member. This is done at a point in time before any instructions
are rewritten by the verifier. Any unstable map file descriptor
number part of the imm field will be zeroed for the hash.

fdinfo example output for progs:

  # cat /proc/1590/fdinfo/5
  pos:          0
  flags:        02000002
  mnt_id:       11
  prog_type:    1
  prog_jited:   1
  prog_digest:  b27e8b06da22707513aa97363dfb11c7c3675d28
  memlock:      4096

When programs are pinned and retrieved by an ELF loader, the loader
can check the program's digest through fdinfo and compare it against
one that was generated over the ELF file's program section to see
if the program needs to be reloaded. Furthermore, this can also be
exposed through other means such as netlink in case of a tc cls/act
dump (or xdp in future), but also through tracepoints or other
facilities to identify the program. Other than that, the digest can
also serve as a base name for the work in progress kallsyms support
of programs. The digest doesn't depend/select the crypto layer, since
we need to keep dependencies to a minimum. iproute2 will get support
for this facility.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-05 15:33:11 -05:00

1032 lines
23 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/syscalls.h>
#include <linux/slab.h>
#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/license.h>
#include <linux/filter.h>
#include <linux/version.h>
#include <linux/kernel.h>
DEFINE_PER_CPU(int, bpf_prog_active);
int sysctl_unprivileged_bpf_disabled __read_mostly;
static LIST_HEAD(bpf_map_types);
static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
{
struct bpf_map_type_list *tl;
struct bpf_map *map;
list_for_each_entry(tl, &bpf_map_types, list_node) {
if (tl->type == attr->map_type) {
map = tl->ops->map_alloc(attr);
if (IS_ERR(map))
return map;
map->ops = tl->ops;
map->map_type = attr->map_type;
return map;
}
}
return ERR_PTR(-EINVAL);
}
/* boot time registration of different map implementations */
void bpf_register_map_type(struct bpf_map_type_list *tl)
{
list_add(&tl->list_node, &bpf_map_types);
}
int bpf_map_precharge_memlock(u32 pages)
{
struct user_struct *user = get_current_user();
unsigned long memlock_limit, cur;
memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
cur = atomic_long_read(&user->locked_vm);
free_uid(user);
if (cur + pages > memlock_limit)
return -EPERM;
return 0;
}
static int bpf_map_charge_memlock(struct bpf_map *map)
{
struct user_struct *user = get_current_user();
unsigned long memlock_limit;
memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
atomic_long_add(map->pages, &user->locked_vm);
if (atomic_long_read(&user->locked_vm) > memlock_limit) {
atomic_long_sub(map->pages, &user->locked_vm);
free_uid(user);
return -EPERM;
}
map->user = user;
return 0;
}
static void bpf_map_uncharge_memlock(struct bpf_map *map)
{
struct user_struct *user = map->user;
atomic_long_sub(map->pages, &user->locked_vm);
free_uid(user);
}
/* called from workqueue */
static void bpf_map_free_deferred(struct work_struct *work)
{
struct bpf_map *map = container_of(work, struct bpf_map, work);
bpf_map_uncharge_memlock(map);
/* implementation dependent freeing */
map->ops->map_free(map);
}
static void bpf_map_put_uref(struct bpf_map *map)
{
if (atomic_dec_and_test(&map->usercnt)) {
if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY)
bpf_fd_array_map_clear(map);
}
}
/* decrement map refcnt and schedule it for freeing via workqueue
* (unrelying map implementation ops->map_free() might sleep)
*/
void bpf_map_put(struct bpf_map *map)
{
if (atomic_dec_and_test(&map->refcnt)) {
INIT_WORK(&map->work, bpf_map_free_deferred);
schedule_work(&map->work);
}
}
void bpf_map_put_with_uref(struct bpf_map *map)
{
bpf_map_put_uref(map);
bpf_map_put(map);
}
static int bpf_map_release(struct inode *inode, struct file *filp)
{
struct bpf_map *map = filp->private_data;
if (map->ops->map_release)
map->ops->map_release(map, filp);
bpf_map_put_with_uref(map);
return 0;
}
#ifdef CONFIG_PROC_FS
static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
{
const struct bpf_map *map = filp->private_data;
const struct bpf_array *array;
u32 owner_prog_type = 0;
if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) {
array = container_of(map, struct bpf_array, map);
owner_prog_type = array->owner_prog_type;
}
seq_printf(m,
"map_type:\t%u\n"
"key_size:\t%u\n"
"value_size:\t%u\n"
"max_entries:\t%u\n"
"map_flags:\t%#x\n"
"memlock:\t%llu\n",
map->map_type,
map->key_size,
map->value_size,
map->max_entries,
map->map_flags,
map->pages * 1ULL << PAGE_SHIFT);
if (owner_prog_type)
seq_printf(m, "owner_prog_type:\t%u\n",
owner_prog_type);
}
#endif
static const struct file_operations bpf_map_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = bpf_map_show_fdinfo,
#endif
.release = bpf_map_release,
};
int bpf_map_new_fd(struct bpf_map *map)
{
return anon_inode_getfd("bpf-map", &bpf_map_fops, map,
O_RDWR | O_CLOEXEC);
}
/* helper macro to check that unused fields 'union bpf_attr' are zero */
#define CHECK_ATTR(CMD) \
memchr_inv((void *) &attr->CMD##_LAST_FIELD + \
sizeof(attr->CMD##_LAST_FIELD), 0, \
sizeof(*attr) - \
offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
sizeof(attr->CMD##_LAST_FIELD)) != NULL
#define BPF_MAP_CREATE_LAST_FIELD map_flags
/* called via syscall */
static int map_create(union bpf_attr *attr)
{
struct bpf_map *map;
int err;
err = CHECK_ATTR(BPF_MAP_CREATE);
if (err)
return -EINVAL;
/* find map type and init map: hashtable vs rbtree vs bloom vs ... */
map = find_and_alloc_map(attr);
if (IS_ERR(map))
return PTR_ERR(map);
atomic_set(&map->refcnt, 1);
atomic_set(&map->usercnt, 1);
err = bpf_map_charge_memlock(map);
if (err)
goto free_map_nouncharge;
err = bpf_map_new_fd(map);
if (err < 0)
/* failed to allocate fd */
goto free_map;
return err;
free_map:
bpf_map_uncharge_memlock(map);
free_map_nouncharge:
map->ops->map_free(map);
return err;
}
/* if error is returned, fd is released.
* On success caller should complete fd access with matching fdput()
*/
struct bpf_map *__bpf_map_get(struct fd f)
{
if (!f.file)
return ERR_PTR(-EBADF);
if (f.file->f_op != &bpf_map_fops) {
fdput(f);
return ERR_PTR(-EINVAL);
}
return f.file->private_data;
}
/* prog's and map's refcnt limit */
#define BPF_MAX_REFCNT 32768
struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref)
{
if (atomic_inc_return(&map->refcnt) > BPF_MAX_REFCNT) {
atomic_dec(&map->refcnt);
return ERR_PTR(-EBUSY);
}
if (uref)
atomic_inc(&map->usercnt);
return map;
}
struct bpf_map *bpf_map_get_with_uref(u32 ufd)
{
struct fd f = fdget(ufd);
struct bpf_map *map;
map = __bpf_map_get(f);
if (IS_ERR(map))
return map;
map = bpf_map_inc(map, true);
fdput(f);
return map;
}
int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
{
return -ENOTSUPP;
}
/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
static int map_lookup_elem(union bpf_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
void __user *uvalue = u64_to_user_ptr(attr->value);
int ufd = attr->map_fd;
struct bpf_map *map;
void *key, *value, *ptr;
u32 value_size;
struct fd f;
int err;
if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
err = -ENOMEM;
key = kmalloc(map->key_size, GFP_USER);
if (!key)
goto err_put;
err = -EFAULT;
if (copy_from_user(key, ukey, map->key_size) != 0)
goto free_key;
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
value_size = round_up(map->value_size, 8) * num_possible_cpus();
else
value_size = map->value_size;
err = -ENOMEM;
value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
if (!value)
goto free_key;
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
err = bpf_percpu_hash_copy(map, key, value);
} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
err = bpf_percpu_array_copy(map, key, value);
} else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
err = bpf_stackmap_copy(map, key, value);
} else {
rcu_read_lock();
ptr = map->ops->map_lookup_elem(map, key);
if (ptr)
memcpy(value, ptr, value_size);
rcu_read_unlock();
err = ptr ? 0 : -ENOENT;
}
if (err)
goto free_value;
err = -EFAULT;
if (copy_to_user(uvalue, value, value_size) != 0)
goto free_value;
err = 0;
free_value:
kfree(value);
free_key:
kfree(key);
err_put:
fdput(f);
return err;
}
#define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
static int map_update_elem(union bpf_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
void __user *uvalue = u64_to_user_ptr(attr->value);
int ufd = attr->map_fd;
struct bpf_map *map;
void *key, *value;
u32 value_size;
struct fd f;
int err;
if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM))
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
err = -ENOMEM;
key = kmalloc(map->key_size, GFP_USER);
if (!key)
goto err_put;
err = -EFAULT;
if (copy_from_user(key, ukey, map->key_size) != 0)
goto free_key;
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
value_size = round_up(map->value_size, 8) * num_possible_cpus();
else
value_size = map->value_size;
err = -ENOMEM;
value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
if (!value)
goto free_key;
err = -EFAULT;
if (copy_from_user(value, uvalue, value_size) != 0)
goto free_value;
/* must increment bpf_prog_active to avoid kprobe+bpf triggering from
* inside bpf map update or delete otherwise deadlocks are possible
*/
preempt_disable();
__this_cpu_inc(bpf_prog_active);
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
err = bpf_percpu_hash_update(map, key, value, attr->flags);
} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
err = bpf_percpu_array_update(map, key, value, attr->flags);
} else if (map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY ||
map->map_type == BPF_MAP_TYPE_PROG_ARRAY ||
map->map_type == BPF_MAP_TYPE_CGROUP_ARRAY) {
rcu_read_lock();
err = bpf_fd_array_map_update_elem(map, f.file, key, value,
attr->flags);
rcu_read_unlock();
} else {
rcu_read_lock();
err = map->ops->map_update_elem(map, key, value, attr->flags);
rcu_read_unlock();
}
__this_cpu_dec(bpf_prog_active);
preempt_enable();
free_value:
kfree(value);
free_key:
kfree(key);
err_put:
fdput(f);
return err;
}
#define BPF_MAP_DELETE_ELEM_LAST_FIELD key
static int map_delete_elem(union bpf_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
int ufd = attr->map_fd;
struct bpf_map *map;
struct fd f;
void *key;
int err;
if (CHECK_ATTR(BPF_MAP_DELETE_ELEM))
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
err = -ENOMEM;
key = kmalloc(map->key_size, GFP_USER);
if (!key)
goto err_put;
err = -EFAULT;
if (copy_from_user(key, ukey, map->key_size) != 0)
goto free_key;
preempt_disable();
__this_cpu_inc(bpf_prog_active);
rcu_read_lock();
err = map->ops->map_delete_elem(map, key);
rcu_read_unlock();
__this_cpu_dec(bpf_prog_active);
preempt_enable();
free_key:
kfree(key);
err_put:
fdput(f);
return err;
}
/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key
static int map_get_next_key(union bpf_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
void __user *unext_key = u64_to_user_ptr(attr->next_key);
int ufd = attr->map_fd;
struct bpf_map *map;
void *key, *next_key;
struct fd f;
int err;
if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY))
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
err = -ENOMEM;
key = kmalloc(map->key_size, GFP_USER);
if (!key)
goto err_put;
err = -EFAULT;
if (copy_from_user(key, ukey, map->key_size) != 0)
goto free_key;
err = -ENOMEM;
next_key = kmalloc(map->key_size, GFP_USER);
if (!next_key)
goto free_key;
rcu_read_lock();
err = map->ops->map_get_next_key(map, key, next_key);
rcu_read_unlock();
if (err)
goto free_next_key;
err = -EFAULT;
if (copy_to_user(unext_key, next_key, map->key_size) != 0)
goto free_next_key;
err = 0;
free_next_key:
kfree(next_key);
free_key:
kfree(key);
err_put:
fdput(f);
return err;
}
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;
}
#ifdef CONFIG_PROC_FS
static void bpf_prog_show_fdinfo(struct seq_file *m, struct file *filp)
{
const struct bpf_prog *prog = filp->private_data;
char prog_digest[sizeof(prog->digest) * 2 + 1] = { };
bin2hex(prog_digest, prog->digest, sizeof(prog->digest));
seq_printf(m,
"prog_type:\t%u\n"
"prog_jited:\t%u\n"
"prog_digest:\t%s\n"
"memlock:\t%llu\n",
prog->type,
prog->jited,
prog_digest,
prog->pages * 1ULL << PAGE_SHIFT);
}
#endif
static const struct file_operations bpf_prog_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = bpf_prog_show_fdinfo,
#endif
.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);
void bpf_prog_sub(struct bpf_prog *prog, int i)
{
/* Only to be used for undoing previous bpf_prog_add() in some
* error path. We still know that another entity in our call
* path holds a reference to the program, thus atomic_sub() can
* be safely used in such cases!
*/
WARN_ON(atomic_sub_return(i, &prog->aux->refcnt) == 0);
}
EXPORT_SYMBOL_GPL(bpf_prog_sub);
struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
{
return bpf_prog_add(prog, 1);
}
EXPORT_SYMBOL_GPL(bpf_prog_inc);
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_user_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_user_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_user_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_user_ptr(attr->pathname));
}
#ifdef CONFIG_CGROUP_BPF
#define BPF_PROG_ATTACH_LAST_FIELD attach_type
static int bpf_prog_attach(const union bpf_attr *attr)
{
struct bpf_prog *prog;
struct cgroup *cgrp;
enum bpf_prog_type ptype;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (CHECK_ATTR(BPF_PROG_ATTACH))
return -EINVAL;
switch (attr->attach_type) {
case BPF_CGROUP_INET_INGRESS:
case BPF_CGROUP_INET_EGRESS:
ptype = BPF_PROG_TYPE_CGROUP_SKB;
break;
case BPF_CGROUP_INET_SOCK_CREATE:
ptype = BPF_PROG_TYPE_CGROUP_SOCK;
break;
default:
return -EINVAL;
}
prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
if (IS_ERR(prog))
return PTR_ERR(prog);
cgrp = cgroup_get_from_fd(attr->target_fd);
if (IS_ERR(cgrp)) {
bpf_prog_put(prog);
return PTR_ERR(cgrp);
}
cgroup_bpf_update(cgrp, prog, attr->attach_type);
cgroup_put(cgrp);
return 0;
}
#define BPF_PROG_DETACH_LAST_FIELD attach_type
static int bpf_prog_detach(const union bpf_attr *attr)
{
struct cgroup *cgrp;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (CHECK_ATTR(BPF_PROG_DETACH))
return -EINVAL;
switch (attr->attach_type) {
case BPF_CGROUP_INET_INGRESS:
case BPF_CGROUP_INET_EGRESS:
case BPF_CGROUP_INET_SOCK_CREATE:
cgrp = cgroup_get_from_fd(attr->target_fd);
if (IS_ERR(cgrp))
return PTR_ERR(cgrp);
cgroup_bpf_update(cgrp, NULL, attr->attach_type);
cgroup_put(cgrp);
break;
default:
return -EINVAL;
}
return 0;
}
#endif /* CONFIG_CGROUP_BPF */
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;
#ifdef CONFIG_CGROUP_BPF
case BPF_PROG_ATTACH:
err = bpf_prog_attach(&attr);
break;
case BPF_PROG_DETACH:
err = bpf_prog_detach(&attr);
break;
#endif
default:
err = -EINVAL;
break;
}
return err;
}