blob: 209e6567cdab051df2d3640cac5b83ce577866eb [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*/
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/bpf_lirc.h>
#include <linux/bpf_verifier.h>
#include <linux/btf.h>
#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/vmalloc.h>
#include <linux/mmzone.h>
#include <linux/anon_inodes.h>
#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/license.h>
#include <linux/filter.h>
#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/idr.h>
#include <linux/cred.h>
#include <linux/timekeeping.h>
#include <linux/ctype.h>
#include <linux/nospec.h>
#include <linux/audit.h>
#include <uapi/linux/btf.h>
#include <linux/pgtable.h>
#include <linux/bpf_lsm.h>
#include <linux/poll.h>
#include <linux/bpf-netns.h>
#include <linux/rcupdate_trace.h>
#define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
(map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \
(map)->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS)
#define IS_FD_PROG_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY)
#define IS_FD_HASH(map) ((map)->map_type == BPF_MAP_TYPE_HASH_OF_MAPS)
#define IS_FD_MAP(map) (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map) || \
IS_FD_HASH(map))
#define BPF_OBJ_FLAG_MASK (BPF_F_RDONLY | BPF_F_WRONLY)
DEFINE_PER_CPU(int, bpf_prog_active);
static DEFINE_IDR(prog_idr);
static DEFINE_SPINLOCK(prog_idr_lock);
static DEFINE_IDR(map_idr);
static DEFINE_SPINLOCK(map_idr_lock);
static DEFINE_IDR(link_idr);
static DEFINE_SPINLOCK(link_idr_lock);
int sysctl_unprivileged_bpf_disabled __read_mostly =
IS_BUILTIN(CONFIG_BPF_UNPRIV_DEFAULT_OFF) ? 2 : 0;
static const struct bpf_map_ops * const bpf_map_types[] = {
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
#define BPF_MAP_TYPE(_id, _ops) \
[_id] = &_ops,
#define BPF_LINK_TYPE(_id, _name)
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE
};
/*
* 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 don't know about yet.
*
* There is a ToCToU between this function call and the following
* copy_from_user() call. However, this is not a concern since this function is
* meant to be a future-proofing of bits.
*/
int bpf_check_uarg_tail_zero(void __user *uaddr,
size_t expected_size,
size_t actual_size)
{
unsigned char __user *addr = uaddr + expected_size;
int res;
if (unlikely(actual_size > PAGE_SIZE)) /* silly large */
return -E2BIG;
if (actual_size <= expected_size)
return 0;
res = check_zeroed_user(addr, actual_size - expected_size);
if (res < 0)
return res;
return res ? 0 : -E2BIG;
}
const struct bpf_map_ops bpf_map_offload_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc = bpf_map_offload_map_alloc,
.map_free = bpf_map_offload_map_free,
.map_check_btf = map_check_no_btf,
};
static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
{
const struct bpf_map_ops *ops;
u32 type = attr->map_type;
struct bpf_map *map;
int err;
if (type >= ARRAY_SIZE(bpf_map_types))
return ERR_PTR(-EINVAL);
type = array_index_nospec(type, ARRAY_SIZE(bpf_map_types));
ops = bpf_map_types[type];
if (!ops)
return ERR_PTR(-EINVAL);
if (ops->map_alloc_check) {
err = ops->map_alloc_check(attr);
if (err)
return ERR_PTR(err);
}
if (attr->map_ifindex)
ops = &bpf_map_offload_ops;
map = ops->map_alloc(attr);
if (IS_ERR(map))
return map;
map->ops = ops;
map->map_type = type;
return map;
}
static void bpf_map_write_active_inc(struct bpf_map *map)
{
atomic64_inc(&map->writecnt);
}
static void bpf_map_write_active_dec(struct bpf_map *map)
{
atomic64_dec(&map->writecnt);
}
bool bpf_map_write_active(const struct bpf_map *map)
{
return atomic64_read(&map->writecnt) != 0;
}
static u32 bpf_map_value_size(struct bpf_map *map)
{
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 ||
map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
return round_up(map->value_size, 8) * num_possible_cpus();
else if (IS_FD_MAP(map))
return sizeof(u32);
else
return map->value_size;
}
static void maybe_wait_bpf_programs(struct bpf_map *map)
{
/* Wait for any running BPF programs to complete so that
* userspace, when we return to it, knows that all programs
* that could be running use the new map value.
*/
if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS ||
map->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS)
synchronize_rcu();
}
static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key,
void *value, __u64 flags)
{
int err;
/* Need to create a kthread, thus must support schedule */
if (bpf_map_is_dev_bound(map)) {
return bpf_map_offload_update_elem(map, key, value, flags);
} else if (map->map_type == BPF_MAP_TYPE_CPUMAP ||
map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
return map->ops->map_update_elem(map, key, value, flags);
} else if (map->map_type == BPF_MAP_TYPE_SOCKHASH ||
map->map_type == BPF_MAP_TYPE_SOCKMAP) {
return sock_map_update_elem_sys(map, key, value, flags);
} else if (IS_FD_PROG_ARRAY(map)) {
return bpf_fd_array_map_update_elem(map, f.file, key, value,
flags);
}
bpf_disable_instrumentation();
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, flags);
} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
err = bpf_percpu_array_update(map, key, value, flags);
} else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
err = bpf_percpu_cgroup_storage_update(map, key, value,
flags);
} else if (IS_FD_ARRAY(map)) {
rcu_read_lock();
err = bpf_fd_array_map_update_elem(map, f.file, key, value,
flags);
rcu_read_unlock();
} else if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
rcu_read_lock();
err = bpf_fd_htab_map_update_elem(map, f.file, key, value,
flags);
rcu_read_unlock();
} else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
/* rcu_read_lock() is not needed */
err = bpf_fd_reuseport_array_update_elem(map, key, value,
flags);
} else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
map->map_type == BPF_MAP_TYPE_STACK) {
err = map->ops->map_push_elem(map, value, flags);
} else {
rcu_read_lock();
err = map->ops->map_update_elem(map, key, value, flags);
rcu_read_unlock();
}
bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
return err;
}
static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value,
__u64 flags)
{
void *ptr;
int err;
if (bpf_map_is_dev_bound(map))
return bpf_map_offload_lookup_elem(map, key, value);
bpf_disable_instrumentation();
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_PERCPU_CGROUP_STORAGE) {
err = bpf_percpu_cgroup_storage_copy(map, key, value);
} else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
err = bpf_stackmap_copy(map, key, value);
} else if (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map)) {
err = bpf_fd_array_map_lookup_elem(map, key, value);
} else if (IS_FD_HASH(map)) {
err = bpf_fd_htab_map_lookup_elem(map, key, value);
} else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
err = bpf_fd_reuseport_array_lookup_elem(map, key, value);
} else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
map->map_type == BPF_MAP_TYPE_STACK) {
err = map->ops->map_peek_elem(map, value);
} else if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
/* struct_ops map requires directly updating "value" */
err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
} else {
rcu_read_lock();
if (map->ops->map_lookup_elem_sys_only)
ptr = map->ops->map_lookup_elem_sys_only(map, key);
else
ptr = map->ops->map_lookup_elem(map, key);
if (IS_ERR(ptr)) {
err = PTR_ERR(ptr);
} else if (!ptr) {
err = -ENOENT;
} else {
err = 0;
if (flags & BPF_F_LOCK)
/* lock 'ptr' and copy everything but lock */
copy_map_value_locked(map, value, ptr, true);
else
copy_map_value(map, value, ptr);
/* mask lock, since value wasn't zero inited */
check_and_init_map_lock(map, value);
}
rcu_read_unlock();
}
bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
return err;
}
static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)
{
/* We really just want to fail instead of triggering OOM killer
* under memory pressure, therefore we set __GFP_NORETRY to kmalloc,
* which is used for lower order allocation requests.
*
* It has been observed that higher order allocation requests done by
* vmalloc with __GFP_NORETRY being set might fail due to not trying
* to reclaim memory from the page cache, thus we set
* __GFP_RETRY_MAYFAIL to avoid such situations.
*/
const gfp_t gfp = __GFP_NOWARN | __GFP_ZERO;
unsigned int flags = 0;
unsigned long align = 1;
void *area;
if (size >= SIZE_MAX)
return NULL;
/* kmalloc()'ed memory can't be mmap()'ed */
if (mmapable) {
BUG_ON(!PAGE_ALIGNED(size));
align = SHMLBA;
flags = VM_USERMAP;
} else if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
area = kmalloc_node(size, gfp | GFP_USER | __GFP_NORETRY,
numa_node);
if (area != NULL)
return area;
}
return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
gfp | GFP_KERNEL | __GFP_RETRY_MAYFAIL, PAGE_KERNEL,
flags, numa_node, __builtin_return_address(0));
}
void *bpf_map_area_alloc(u64 size, int numa_node)
{
return __bpf_map_area_alloc(size, numa_node, false);
}
void *bpf_map_area_mmapable_alloc(u64 size, int numa_node)
{
return __bpf_map_area_alloc(size, numa_node, true);
}
void bpf_map_area_free(void *area)
{
kvfree(area);
}
static u32 bpf_map_flags_retain_permanent(u32 flags)
{
/* Some map creation flags are not tied to the map object but
* rather to the map fd instead, so they have no meaning upon
* map object inspection since multiple file descriptors with
* different (access) properties can exist here. Thus, given
* this has zero meaning for the map itself, lets clear these
* from here.
*/
return flags & ~(BPF_F_RDONLY | BPF_F_WRONLY);
}
void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr)
{
map->map_type = attr->map_type;
map->key_size = attr->key_size;
map->value_size = attr->value_size;
map->max_entries = attr->max_entries;
map->map_flags = bpf_map_flags_retain_permanent(attr->map_flags);
map->numa_node = bpf_map_attr_numa_node(attr);
}
static int bpf_charge_memlock(struct user_struct *user, u32 pages)
{
unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (atomic_long_add_return(pages, &user->locked_vm) > memlock_limit) {
atomic_long_sub(pages, &user->locked_vm);
return -EPERM;
}
return 0;
}
static void bpf_uncharge_memlock(struct user_struct *user, u32 pages)
{
if (user)
atomic_long_sub(pages, &user->locked_vm);
}
int bpf_map_charge_init(struct bpf_map_memory *mem, u64 size)
{
u32 pages = round_up(size, PAGE_SIZE) >> PAGE_SHIFT;
struct user_struct *user;
int ret;
if (size >= U32_MAX - PAGE_SIZE)
return -E2BIG;
user = get_current_user();
ret = bpf_charge_memlock(user, pages);
if (ret) {
free_uid(user);
return ret;
}
mem->pages = pages;
mem->user = user;
return 0;
}
void bpf_map_charge_finish(struct bpf_map_memory *mem)
{
bpf_uncharge_memlock(mem->user, mem->pages);
free_uid(mem->user);
}
void bpf_map_charge_move(struct bpf_map_memory *dst,
struct bpf_map_memory *src)
{
*dst = *src;
/* Make sure src will not be used for the redundant uncharging. */
memset(src, 0, sizeof(struct bpf_map_memory));
}
int bpf_map_charge_memlock(struct bpf_map *map, u32 pages)
{
int ret;
ret = bpf_charge_memlock(map->memory.user, pages);
if (ret)
return ret;
map->memory.pages += pages;
return ret;
}
void bpf_map_uncharge_memlock(struct bpf_map *map, u32 pages)
{
bpf_uncharge_memlock(map->memory.user, pages);
map->memory.pages -= pages;
}
static int bpf_map_alloc_id(struct bpf_map *map)
{
int id;
idr_preload(GFP_KERNEL);
spin_lock_bh(&map_idr_lock);
id = idr_alloc_cyclic(&map_idr, map, 1, INT_MAX, GFP_ATOMIC);
if (id > 0)
map->id = id;
spin_unlock_bh(&map_idr_lock);
idr_preload_end();
if (WARN_ON_ONCE(!id))
return -ENOSPC;
return id > 0 ? 0 : id;
}
void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock)
{
unsigned long flags;
/* Offloaded maps are removed from the IDR store when their device
* disappears - even if someone holds an fd to them they are unusable,
* the memory is gone, all ops will fail; they are simply waiting for
* refcnt to drop to be freed.
*/
if (!map->id)
return;
if (do_idr_lock)
spin_lock_irqsave(&map_idr_lock, flags);
else
__acquire(&map_idr_lock);
idr_remove(&map_idr, map->id);
map->id = 0;
if (do_idr_lock)
spin_unlock_irqrestore(&map_idr_lock, flags);
else
__release(&map_idr_lock);
}
/* called from workqueue */
static void bpf_map_free_deferred(struct work_struct *work)
{
struct bpf_map *map = container_of(work, struct bpf_map, work);
struct bpf_map_memory mem;
bpf_map_charge_move(&mem, &map->memory);
security_bpf_map_free(map);
/* implementation dependent freeing */
map->ops->map_free(map);
bpf_map_charge_finish(&mem);
}
static void bpf_map_put_uref(struct bpf_map *map)
{
if (atomic64_dec_and_test(&map->usercnt)) {
if (map->ops->map_release_uref)
map->ops->map_release_uref(map);
}
}
/* decrement map refcnt and schedule it for freeing via workqueue
* (unrelying map implementation ops->map_free() might sleep)
*/
static void __bpf_map_put(struct bpf_map *map, bool do_idr_lock)
{
if (atomic64_dec_and_test(&map->refcnt)) {
/* bpf_map_free_id() must be called first */
bpf_map_free_id(map, do_idr_lock);
btf_put(map->btf);
INIT_WORK(&map->work, bpf_map_free_deferred);
schedule_work(&map->work);
}
}
void bpf_map_put(struct bpf_map *map)
{
__bpf_map_put(map, true);
}
EXPORT_SYMBOL_GPL(bpf_map_put);
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;
}
static fmode_t map_get_sys_perms(struct bpf_map *map, struct fd f)
{
fmode_t mode = f.file->f_mode;
/* Our file permissions may have been overridden by global
* map permissions facing syscall side.
*/
if (READ_ONCE(map->frozen))
mode &= ~FMODE_CAN_WRITE;
return mode;
}
#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 type = 0, jited = 0;
if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) {
array = container_of(map, struct bpf_array, map);
spin_lock(&array->aux->owner.lock);
type = array->aux->owner.type;
jited = array->aux->owner.jited;
spin_unlock(&array->aux->owner.lock);
}
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_id:\t%u\n"
"frozen:\t%u\n",
map->map_type,
map->key_size,
map->value_size,
map->max_entries,
map->map_flags,
map->memory.pages * 1ULL << PAGE_SHIFT,
map->id,
READ_ONCE(map->frozen));
if (type) {
seq_printf(m, "owner_prog_type:\t%u\n", type);
seq_printf(m, "owner_jited:\t%u\n", jited);
}
}
#endif
static ssize_t bpf_dummy_read(struct file *filp, char __user *buf, size_t siz,
loff_t *ppos)
{
/* We need this handler such that alloc_file() enables
* f_mode with FMODE_CAN_READ.
*/
return -EINVAL;
}
static ssize_t bpf_dummy_write(struct file *filp, const char __user *buf,
size_t siz, loff_t *ppos)
{
/* We need this handler such that alloc_file() enables
* f_mode with FMODE_CAN_WRITE.
*/
return -EINVAL;
}
/* called for any extra memory-mapped regions (except initial) */
static void bpf_map_mmap_open(struct vm_area_struct *vma)
{
struct bpf_map *map = vma->vm_file->private_data;
if (vma->vm_flags & VM_MAYWRITE)
bpf_map_write_active_inc(map);
}
/* called for all unmapped memory region (including initial) */
static void bpf_map_mmap_close(struct vm_area_struct *vma)
{
struct bpf_map *map = vma->vm_file->private_data;
if (vma->vm_flags & VM_MAYWRITE)
bpf_map_write_active_dec(map);
}
static const struct vm_operations_struct bpf_map_default_vmops = {
.open = bpf_map_mmap_open,
.close = bpf_map_mmap_close,
};
static int bpf_map_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct bpf_map *map = filp->private_data;
int err;
if (!map->ops->map_mmap || map_value_has_spin_lock(map))
return -ENOTSUPP;
if (!(vma->vm_flags & VM_SHARED))
return -EINVAL;
mutex_lock(&map->freeze_mutex);
if (vma->vm_flags & VM_WRITE) {
if (map->frozen) {
err = -EPERM;
goto out;
}
/* map is meant to be read-only, so do not allow mapping as
* writable, because it's possible to leak a writable page
* reference and allows user-space to still modify it after
* freezing, while verifier will assume contents do not change
*/
if (map->map_flags & BPF_F_RDONLY_PROG) {
err = -EACCES;
goto out;
}
}
/* set default open/close callbacks */
vma->vm_ops = &bpf_map_default_vmops;
vma->vm_private_data = map;
vma->vm_flags &= ~VM_MAYEXEC;
if (!(vma->vm_flags & VM_WRITE))
/* disallow re-mapping with PROT_WRITE */
vma->vm_flags &= ~VM_MAYWRITE;
err = map->ops->map_mmap(map, vma);
if (err)
goto out;
if (vma->vm_flags & VM_MAYWRITE)
bpf_map_write_active_inc(map);
out:
mutex_unlock(&map->freeze_mutex);
return err;
}
static __poll_t bpf_map_poll(struct file *filp, struct poll_table_struct *pts)
{
struct bpf_map *map = filp->private_data;
if (map->ops->map_poll)
return map->ops->map_poll(map, filp, pts);
return EPOLLERR;
}
const struct file_operations bpf_map_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = bpf_map_show_fdinfo,
#endif
.release = bpf_map_release,
.read = bpf_dummy_read,
.write = bpf_dummy_write,
.mmap = bpf_map_mmap,
.poll = bpf_map_poll,
};
int bpf_map_new_fd(struct bpf_map *map, int flags)
{
int ret;
ret = security_bpf_map(map, OPEN_FMODE(flags));
if (ret < 0)
return ret;
return anon_inode_getfd("bpf-map", &bpf_map_fops, map,
flags | O_CLOEXEC);
}
int bpf_get_file_flag(int flags)
{
if ((flags & BPF_F_RDONLY) && (flags & BPF_F_WRONLY))
return -EINVAL;
if (flags & BPF_F_RDONLY)
return O_RDONLY;
if (flags & BPF_F_WRONLY)
return O_WRONLY;
return O_RDWR;
}
/* 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
/* dst and src must have at least "size" number of bytes.
* Return strlen on success and < 0 on error.
*/
int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size)
{
const char *end = src + size;
const char *orig_src = src;
memset(dst, 0, size);
/* Copy all isalnum(), '_' and '.' chars. */
while (src < end && *src) {
if (!isalnum(*src) &&
*src != '_' && *src != '.')
return -EINVAL;
*dst++ = *src++;
}
/* No '\0' found in "size" number of bytes */
if (src == end)
return -EINVAL;
return src - orig_src;
}
int map_check_no_btf(const struct bpf_map *map,
const struct btf *btf,
const struct btf_type *key_type,
const struct btf_type *value_type)
{
return -ENOTSUPP;
}
static int map_check_btf(struct bpf_map *map, const struct btf *btf,
u32 btf_key_id, u32 btf_value_id)
{
const struct btf_type *key_type, *value_type;
u32 key_size, value_size;
int ret = 0;
/* Some maps allow key to be unspecified. */
if (btf_key_id) {
key_type = btf_type_id_size(btf, &btf_key_id, &key_size);
if (!key_type || key_size != map->key_size)
return -EINVAL;
} else {
key_type = btf_type_by_id(btf, 0);
if (!map->ops->map_check_btf)
return -EINVAL;
}
value_type = btf_type_id_size(btf, &btf_value_id, &value_size);
if (!value_type || value_size != map->value_size)
return -EINVAL;
map->spin_lock_off = btf_find_spin_lock(btf, value_type);
if (map_value_has_spin_lock(map)) {
if (map->map_flags & BPF_F_RDONLY_PROG)
return -EACCES;
if (map->map_type != BPF_MAP_TYPE_HASH &&
map->map_type != BPF_MAP_TYPE_ARRAY &&
map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
return -ENOTSUPP;
if (map->spin_lock_off + sizeof(struct bpf_spin_lock) >
map->value_size) {
WARN_ONCE(1,
"verifier bug spin_lock_off %d value_size %d\n",
map->spin_lock_off, map->value_size);
return -EFAULT;
}
}
if (map->ops->map_check_btf)
ret = map->ops->map_check_btf(map, btf, key_type, value_type);
return ret;
}
#define BPF_MAP_CREATE_LAST_FIELD btf_vmlinux_value_type_id
/* called via syscall */
static int map_create(union bpf_attr *attr)
{
int numa_node = bpf_map_attr_numa_node(attr);
struct bpf_map_memory mem;
struct bpf_map *map;
int f_flags;
int err;
err = CHECK_ATTR(BPF_MAP_CREATE);
if (err)
return -EINVAL;
if (attr->btf_vmlinux_value_type_id) {
if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS ||
attr->btf_key_type_id || attr->btf_value_type_id)
return -EINVAL;
} else if (attr->btf_key_type_id && !attr->btf_value_type_id) {
return -EINVAL;
}
f_flags = bpf_get_file_flag(attr->map_flags);
if (f_flags < 0)
return f_flags;
if (numa_node != NUMA_NO_NODE &&
((unsigned int)numa_node >= nr_node_ids ||
!node_online(numa_node)))
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);
err = bpf_obj_name_cpy(map->name, attr->map_name,
sizeof(attr->map_name));
if (err < 0)
goto free_map;
atomic64_set(&map->refcnt, 1);
atomic64_set(&map->usercnt, 1);
mutex_init(&map->freeze_mutex);
map->spin_lock_off = -EINVAL;
if (attr->btf_key_type_id || attr->btf_value_type_id ||
/* Even the map's value is a kernel's struct,
* the bpf_prog.o must have BTF to begin with
* to figure out the corresponding kernel's
* counter part. Thus, attr->btf_fd has
* to be valid also.
*/
attr->btf_vmlinux_value_type_id) {
struct btf *btf;
btf = btf_get_by_fd(attr->btf_fd);
if (IS_ERR(btf)) {
err = PTR_ERR(btf);
goto free_map;
}
map->btf = btf;
if (attr->btf_value_type_id) {
err = map_check_btf(map, btf, attr->btf_key_type_id,
attr->btf_value_type_id);
if (err)
goto free_map;
}
map->btf_key_type_id = attr->btf_key_type_id;
map->btf_value_type_id = attr->btf_value_type_id;
map->btf_vmlinux_value_type_id =
attr->btf_vmlinux_value_type_id;
}
err = security_bpf_map_alloc(map);
if (err)
goto free_map;
err = bpf_map_alloc_id(map);
if (err)
goto free_map_sec;
err = bpf_map_new_fd(map, f_flags);
if (err < 0) {
/* failed to allocate fd.
* bpf_map_put_with_uref() is needed because the above
* bpf_map_alloc_id() has published the map
* to the userspace and the userspace may
* have refcnt-ed it through BPF_MAP_GET_FD_BY_ID.
*/
bpf_map_put_with_uref(map);
return err;
}
return err;
free_map_sec:
security_bpf_map_free(map);
free_map:
btf_put(map->btf);
bpf_map_charge_move(&mem, &map->memory);
map->ops->map_free(map);
bpf_map_charge_finish(&mem);
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;
}
void bpf_map_inc(struct bpf_map *map)
{
atomic64_inc(&map->refcnt);
}
EXPORT_SYMBOL_GPL(bpf_map_inc);
void bpf_map_inc_with_uref(struct bpf_map *map)
{
atomic64_inc(&map->refcnt);
atomic64_inc(&map->usercnt);
}
EXPORT_SYMBOL_GPL(bpf_map_inc_with_uref);
struct bpf_map *bpf_map_get(u32 ufd)
{
struct fd f = fdget(ufd);
struct bpf_map *map;
map = __bpf_map_get(f);
if (IS_ERR(map))
return map;
bpf_map_inc(map);
fdput(f);
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;
bpf_map_inc_with_uref(map);
fdput(f);
return map;
}
/* map_idr_lock should have been held */
static struct bpf_map *__bpf_map_inc_not_zero(struct bpf_map *map, bool uref)
{
int refold;
refold = atomic64_fetch_add_unless(&map->refcnt, 1, 0);
if (!refold)
return ERR_PTR(-ENOENT);
if (uref)
atomic64_inc(&map->usercnt);
return map;
}
struct bpf_map *bpf_map_inc_not_zero(struct bpf_map *map)
{
spin_lock_bh(&map_idr_lock);
map = __bpf_map_inc_not_zero(map, false);
spin_unlock_bh(&map_idr_lock);
return map;
}
EXPORT_SYMBOL_GPL(bpf_map_inc_not_zero);
int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
{
return -ENOTSUPP;
}
static void *__bpf_copy_key(void __user *ukey, u64 key_size)
{
if (key_size)
return memdup_user(ukey, key_size);
if (ukey)
return ERR_PTR(-EINVAL);
return NULL;
}
/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD flags
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;
u32 value_size;
struct fd f;
int err;
if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
return -EINVAL;
if (attr->flags & ~BPF_F_LOCK)
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
err = -EPERM;
goto err_put;
}
if ((attr->flags & BPF_F_LOCK) &&
!map_value_has_spin_lock(map)) {
err = -EINVAL;
goto err_put;
}
key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
}
value_size = bpf_map_value_size(map);
err = -ENOMEM;
value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
if (!value)
goto free_key;
err = bpf_map_copy_value(map, key, value, attr->flags);
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);
bpf_map_write_active_inc(map);
if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
err = -EPERM;
goto err_put;
}
if ((attr->flags & BPF_F_LOCK) &&
!map_value_has_spin_lock(map)) {
err = -EINVAL;
goto err_put;
}
key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
}
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 ||
map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
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;
err = bpf_map_update_value(map, f, key, value, attr->flags);
free_value:
kfree(value);
free_key:
kfree(key);
err_put:
bpf_map_write_active_dec(map);
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);
bpf_map_write_active_inc(map);
if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
err = -EPERM;
goto err_put;
}
key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
}
if (bpf_map_is_dev_bound(map)) {
err = bpf_map_offload_delete_elem(map, key);
goto out;
} else if (IS_FD_PROG_ARRAY(map) ||
map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
/* These maps require sleepable context */
err = map->ops->map_delete_elem(map, key);
goto out;
}
bpf_disable_instrumentation();
rcu_read_lock();
err = map->ops->map_delete_elem(map, key);
rcu_read_unlock();
bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
out:
kfree(key);
err_put:
bpf_map_write_active_dec(map);
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);
if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
err = -EPERM;
goto err_put;
}
if (ukey) {
key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
}
} else {
key = NULL;
}
err = -ENOMEM;
next_key = kmalloc(map->key_size, GFP_USER);
if (!next_key)
goto free_key;
if (bpf_map_is_dev_bound(map)) {
err = bpf_map_offload_get_next_key(map, key, next_key);
goto out;
}
rcu_read_lock();
err = map->ops->map_get_next_key(map, key, next_key);
rcu_read_unlock();
out:
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;
}
int generic_map_delete_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
void __user *keys = u64_to_user_ptr(attr->batch.keys);
u32 cp, max_count;
int err = 0;
void *key;
if (attr->batch.elem_flags & ~BPF_F_LOCK)
return -EINVAL;
if ((attr->batch.elem_flags & BPF_F_LOCK) &&
!map_value_has_spin_lock(map)) {
return -EINVAL;
}
max_count = attr->batch.count;
if (!max_count)
return 0;
key = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
if (!key)
return -ENOMEM;
for (cp = 0; cp < max_count; cp++) {
err = -EFAULT;
if (copy_from_user(key, keys + cp * map->key_size,
map->key_size))
break;
if (bpf_map_is_dev_bound(map)) {
err = bpf_map_offload_delete_elem(map, key);
break;
}
bpf_disable_instrumentation();
rcu_read_lock();
err = map->ops->map_delete_elem(map, key);
rcu_read_unlock();
bpf_enable_instrumentation();
maybe_wait_bpf_programs(map);
if (err)
break;
}
if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
err = -EFAULT;
kfree(key);
return err;
}
int generic_map_update_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
void __user *values = u64_to_user_ptr(attr->batch.values);
void __user *keys = u64_to_user_ptr(attr->batch.keys);
u32 value_size, cp, max_count;
int ufd = attr->batch.map_fd;
void *key, *value;
struct fd f;
int err = 0;
if (attr->batch.elem_flags & ~BPF_F_LOCK)
return -EINVAL;
if ((attr->batch.elem_flags & BPF_F_LOCK) &&
!map_value_has_spin_lock(map)) {
return -EINVAL;
}
value_size = bpf_map_value_size(map);
max_count = attr->batch.count;
if (!max_count)
return 0;
key = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
if (!key)
return -ENOMEM;
value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
if (!value) {
kfree(key);
return -ENOMEM;
}
f = fdget(ufd); /* bpf_map_do_batch() guarantees ufd is valid */
for (cp = 0; cp < max_count; cp++) {
err = -EFAULT;
if (copy_from_user(key, keys + cp * map->key_size,
map->key_size) ||
copy_from_user(value, values + cp * value_size, value_size))
break;
err = bpf_map_update_value(map, f, key, value,
attr->batch.elem_flags);
if (err)
break;
}
if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
err = -EFAULT;
kfree(value);
kfree(key);
fdput(f);
return err;
}
#define MAP_LOOKUP_RETRIES 3
int generic_map_lookup_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
void __user *uobatch = u64_to_user_ptr(attr->batch.out_batch);
void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
void __user *values = u64_to_user_ptr(attr->batch.values);
void __user *keys = u64_to_user_ptr(attr->batch.keys);
void *buf, *buf_prevkey, *prev_key, *key, *value;
int err, retry = MAP_LOOKUP_RETRIES;
u32 value_size, cp, max_count;
if (attr->batch.elem_flags & ~BPF_F_LOCK)
return -EINVAL;
if ((attr->batch.elem_flags & BPF_F_LOCK) &&
!map_value_has_spin_lock(map))
return -EINVAL;
value_size = bpf_map_value_size(map);
max_count = attr->batch.count;
if (!max_count)
return 0;
if (put_user(0, &uattr->batch.count))
return -EFAULT;
buf_prevkey = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
if (!buf_prevkey)
return -ENOMEM;
buf = kmalloc(map->key_size + value_size, GFP_USER | __GFP_NOWARN);
if (!buf) {
kfree(buf_prevkey);
return -ENOMEM;
}
err = -EFAULT;
prev_key = NULL;
if (ubatch && copy_from_user(buf_prevkey, ubatch, map->key_size))
goto free_buf;
key = buf;
value = key + map->key_size;
if (ubatch)
prev_key = buf_prevkey;
for (cp = 0; cp < max_count;) {
rcu_read_lock();
err = map->ops->map_get_next_key(map, prev_key, key);
rcu_read_unlock();
if (err)
break;
err = bpf_map_copy_value(map, key, value,
attr->batch.elem_flags);
if (err == -ENOENT) {
if (retry) {
retry--;
continue;
}
err = -EINTR;
break;
}
if (err)
goto free_buf;
if (copy_to_user(keys + cp * map->key_size, key,
map->key_size)) {
err = -EFAULT;
goto free_buf;
}
if (copy_to_user(values + cp * value_size, value, value_size)) {
err = -EFAULT;
goto free_buf;
}
if (!prev_key)
prev_key = buf_prevkey;
swap(prev_key, key);
retry = MAP_LOOKUP_RETRIES;
cp++;
}
if (err == -EFAULT)
goto free_buf;
if ((copy_to_user(&uattr->batch.count, &cp, sizeof(cp)) ||
(cp && copy_to_user(uobatch, prev_key, map->key_size))))
err = -EFAULT;
free_buf:
kfree(buf_prevkey);
kfree(buf);
return err;
}
#define BPF_MAP_LOOKUP_AND_DELETE_ELEM_LAST_FIELD value
static int map_lookup_and_delete_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_LOOKUP_AND_DELETE_ELEM))
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
bpf_map_write_active_inc(map);
if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ) ||
!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
err = -EPERM;
goto err_put;
}
key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
}
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_QUEUE ||
map->map_type == BPF_MAP_TYPE_STACK) {
err = map->ops->map_pop_elem(map, value);
} else {
err = -ENOTSUPP;
}
if (err)
goto free_value;
if (copy_to_user(uvalue, value, value_size) != 0) {
err = -EFAULT;
goto free_value;
}
err = 0;
free_value:
kfree(value);
free_key:
kfree(key);
err_put:
bpf_map_write_active_dec(map);
fdput(f);
return err;
}
#define BPF_MAP_FREEZE_LAST_FIELD map_fd
static int map_freeze(const union bpf_attr *attr)
{
int err = 0, ufd = attr->map_fd;
struct bpf_map *map;
struct fd f;
if (CHECK_ATTR(BPF_MAP_FREEZE))
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
fdput(f);
return -ENOTSUPP;
}
mutex_lock(&map->freeze_mutex);
if (bpf_map_write_active(map)) {
err = -EBUSY;
goto err_put;
}
if (READ_ONCE(map->frozen)) {
err = -EBUSY;
goto err_put;
}
if (!bpf_capable()) {
err = -EPERM;
goto err_put;
}
WRITE_ONCE(map->frozen, true);
err_put:
mutex_unlock(&map->freeze_mutex);
fdput(f);
return err;
}
static const struct bpf_prog_ops * const bpf_prog_types[] = {
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
[_id] = & _name ## _prog_ops,
#define BPF_MAP_TYPE(_id, _ops)
#define BPF_LINK_TYPE(_id, _name)
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE
};
static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
{
const struct bpf_prog_ops *ops;
if (type >= ARRAY_SIZE(bpf_prog_types))
return -EINVAL;
type = array_index_nospec(type, ARRAY_SIZE(bpf_prog_types));
ops = bpf_prog_types[type];
if (!ops)
return -EINVAL;
if (!bpf_prog_is_dev_bound(prog->aux))
prog->aux->ops = ops;
else
prog->aux->ops = &bpf_offload_prog_ops;
prog->type = type;
return 0;
}
enum bpf_audit {
BPF_AUDIT_LOAD,
BPF_AUDIT_UNLOAD,
BPF_AUDIT_MAX,
};
static const char * const bpf_audit_str[BPF_AUDIT_MAX] = {
[BPF_AUDIT_LOAD] = "LOAD",
[BPF_AUDIT_UNLOAD] = "UNLOAD",
};
static void bpf_audit_prog(const struct bpf_prog *prog, unsigned int op)
{
struct audit_context *ctx = NULL;
struct audit_buffer *ab;
if (WARN_ON_ONCE(op >= BPF_AUDIT_MAX))
return;
if (audit_enabled == AUDIT_OFF)
return;
if (op == BPF_AUDIT_LOAD)
ctx = audit_context();
ab = audit_log_start(ctx, GFP_ATOMIC, AUDIT_BPF);
if (unlikely(!ab))
return;
audit_log_format(ab, "prog-id=%u op=%s",
prog->aux->id, bpf_audit_str[op]);
audit_log_end(ab);
}
int __bpf_prog_charge(struct user_struct *user, u32 pages)
{
unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
unsigned long user_bufs;
if (user) {
user_bufs = atomic_long_add_return(pages, &user->locked_vm);
if (user_bufs > memlock_limit) {
atomic_long_sub(pages, &user->locked_vm);
return -EPERM;
}
}
return 0;
}
void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
{
if (user)
atomic_long_sub(pages, &user->locked_vm);
}
static int bpf_prog_charge_memlock(struct bpf_prog *prog)
{
struct user_struct *user = get_current_user();
int ret;
ret = __bpf_prog_charge(user, prog->pages);
if (ret) {
free_uid(user);
return ret;
}
prog->aux->user = user;
return 0;
}
static void bpf_prog_uncharge_memlock(struct bpf_prog *prog)
{
struct user_struct *user = prog->aux->user;
__bpf_prog_uncharge(user, prog->pages);
free_uid(user);
}
static int bpf_prog_alloc_id(struct bpf_prog *prog)
{
int id;
idr_preload(GFP_KERNEL);
spin_lock_bh(&prog_idr_lock);
id = idr_alloc_cyclic(&prog_idr, prog, 1, INT_MAX, GFP_ATOMIC);
if (id > 0)
prog->aux->id = id;
spin_unlock_bh(&prog_idr_lock);
idr_preload_end();
/* id is in [1, INT_MAX) */
if (WARN_ON_ONCE(!id))
return -ENOSPC;
return id > 0 ? 0 : id;
}
void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock)
{
/* cBPF to eBPF migrations are currently not in the idr store.
* Offloaded programs are removed from the store when their device
* disappears - even if someone grabs an fd to them they are unusable,
* simply waiting for refcnt to drop to be freed.
*/
if (!prog->aux->id)
return;
if (do_idr_lock)
spin_lock_bh(&prog_idr_lock);
else
__acquire(&prog_idr_lock);
idr_remove(&prog_idr, prog->aux->id);
prog->aux->id = 0;
if (do_idr_lock)
spin_unlock_bh(&prog_idr_lock);
else
__release(&prog_idr_lock);
}
static void __bpf_prog_put_rcu(struct rcu_head *rcu)
{
struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
kvfree(aux->func_info);
kfree(aux->func_info_aux);
bpf_prog_uncharge_memlock(aux->prog);
security_bpf_prog_free(aux);
bpf_prog_free(aux->prog);
}
static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred)
{
bpf_prog_kallsyms_del_all(prog);
btf_put(prog->aux->btf);
bpf_prog_free_linfo(prog);
if (deferred) {
if (prog->aux->sleepable)
call_rcu_tasks_trace(&prog->aux->rcu, __bpf_prog_put_rcu);
else
call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu);
} else {
__bpf_prog_put_rcu(&prog->aux->rcu);
}
}
static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
{
if (atomic64_dec_and_test(&prog->aux->refcnt)) {
perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0);
bpf_audit_prog(prog, BPF_AUDIT_UNLOAD);
/* bpf_prog_free_id() must be called first */
bpf_prog_free_id(prog, do_idr_lock);
__bpf_prog_put_noref(prog, true);
}
}
void bpf_prog_put(struct bpf_prog *prog)
{
__bpf_prog_put(prog, true);
}
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 void bpf_prog_get_stats(const struct bpf_prog *prog,
struct bpf_prog_stats *stats)
{
u64 nsecs = 0, cnt = 0;
int cpu;
for_each_possible_cpu(cpu) {
const struct bpf_prog_stats *st;
unsigned int start;
u64 tnsecs, tcnt;
st = per_cpu_ptr(prog->aux->stats, cpu);
do {
start = u64_stats_fetch_begin_irq(&st->syncp);
tnsecs = st->nsecs;
tcnt = st->cnt;
} while (u64_stats_fetch_retry_irq(&st->syncp, start));
nsecs += tnsecs;
cnt += tcnt;
}
stats->nsecs = nsecs;
stats->cnt = cnt;
}
#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_tag[sizeof(prog->tag) * 2 + 1] = { };
struct bpf_prog_stats stats;
bpf_prog_get_stats(prog, &stats);
bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
seq_printf(m,
"prog_type:\t%u\n"
"prog_jited:\t%u\n"
"prog_tag:\t%s\n"
"memlock:\t%llu\n"
"prog_id:\t%u\n"
"run_time_ns:\t%llu\n"
"run_cnt:\t%llu\n",
prog->type,
prog->jited,
prog_tag,
prog->pages * 1ULL << PAGE_SHIFT,
prog->aux->id,
stats.nsecs,
stats.cnt);
}
#endif
const struct file_operations bpf_prog_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = bpf_prog_show_fdinfo,
#endif
.release = bpf_prog_release,
.read = bpf_dummy_read,
.write = bpf_dummy_write,
};
int bpf_prog_new_fd(struct bpf_prog *prog)
{
int ret;
ret = security_bpf_prog(prog);
if (ret < 0)
return ret;
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;
}
void bpf_prog_add(struct bpf_prog *prog, int i)
{
atomic64_add(i, &prog->aux->refcnt);
}
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(atomic64_sub_return(i, &prog->aux->refcnt) == 0);
}
EXPORT_SYMBOL_GPL(bpf_prog_sub);
void bpf_prog_inc(struct bpf_prog *prog)
{
atomic64_inc(&prog->aux->refcnt);
}
EXPORT_SYMBOL_GPL(bpf_prog_inc);
/* prog_idr_lock should have been held */
struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog)
{
int refold;
refold = atomic64_fetch_add_unless(&prog->aux->refcnt, 1, 0);
if (!refold)
return ERR_PTR(-ENOENT);
return prog;
}
EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);
bool bpf_prog_get_ok(struct bpf_prog *prog,
enum bpf_prog_type *attach_type, bool attach_drv)
{
/* not an attachment, just a refcount inc, always allow */
if (!attach_type)
return true;
if (prog->type != *attach_type)
return false;
if (bpf_prog_is_dev_bound(prog->aux) && !attach_drv)
return false;
return true;
}
static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
bool attach_drv)
{
struct fd f = fdget(ufd);
struct bpf_prog *prog;
prog = ____bpf_prog_get(f);
if (IS_ERR(prog))
return prog;
if (!bpf_prog_get_ok(prog, attach_type, attach_drv)) {
prog = ERR_PTR(-EINVAL);
goto out;
}
bpf_prog_inc(prog);
out:
fdput(f);
return prog;
}
struct bpf_prog *bpf_prog_get(u32 ufd)
{
return __bpf_prog_get(ufd, NULL, false);
}
struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
bool attach_drv)
{
return __bpf_prog_get(ufd, &type, attach_drv);
}
EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev);
/* Initially all BPF programs could be loaded w/o specifying
* expected_attach_type. Later for some of them specifying expected_attach_type
* at load time became required so that program could be validated properly.
* Programs of types that are allowed to be loaded both w/ and w/o (for
* backward compatibility) expected_attach_type, should have the default attach
* type assigned to expected_attach_type for the latter case, so that it can be
* validated later at attach time.
*
* bpf_prog_load_fixup_attach_type() sets expected_attach_type in @attr if
* prog type requires it but has some attach types that have to be backward
* compatible.
*/
static void bpf_prog_load_fixup_attach_type(union bpf_attr *attr)
{
switch (attr->prog_type) {
case BPF_PROG_TYPE_CGROUP_SOCK:
/* Unfortunately BPF_ATTACH_TYPE_UNSPEC enumeration doesn't
* exist so checking for non-zero is the way to go here.
*/
if (!attr->expected_attach_type)
attr->expected_attach_type =
BPF_CGROUP_INET_SOCK_CREATE;
break;
}
}
static int
bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
enum bpf_attach_type expected_attach_type,
u32 btf_id, u32 prog_fd)
{
if (btf_id) {
if (btf_id > BTF_MAX_TYPE)
return -EINVAL;
switch (prog_type) {
case BPF_PROG_TYPE_TRACING:
case BPF_PROG_TYPE_LSM:
case BPF_PROG_TYPE_STRUCT_OPS:
case BPF_PROG_TYPE_EXT:
break;
default:
return -EINVAL;
}
}
if (prog_fd && prog_type != BPF_PROG_TYPE_TRACING &&
prog_type != BPF_PROG_TYPE_EXT)
return -EINVAL;
switch (prog_type) {
case BPF_PROG_TYPE_CGROUP_SOCK:
switch (expected_attach_type) {
case BPF_CGROUP_INET_SOCK_CREATE:
case BPF_CGROUP_INET_SOCK_RELEASE:
case BPF_CGROUP_INET4_POST_BIND:
case BPF_CGROUP_INET6_POST_BIND:
return 0;
default:
return -EINVAL;
}
case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
switch (expected_attach_type) {
case BPF_CGROUP_INET4_BIND:
case BPF_CGROUP_INET6_BIND:
case BPF_CGROUP_INET4_CONNECT:
case BPF_CGROUP_INET6_CONNECT:
case BPF_CGROUP_INET4_GETPEERNAME:
case BPF_CGROUP_INET6_GETPEERNAME:
case BPF_CGROUP_INET4_GETSOCKNAME:
case BPF_CGROUP_INET6_GETSOCKNAME:
case BPF_CGROUP_UDP4_SENDMSG:
case BPF_CGROUP_UDP6_SENDMSG:
case BPF_CGROUP_UDP4_RECVMSG:
case BPF_CGROUP_UDP6_RECVMSG:
return 0;
default:
return -EINVAL;
}
case BPF_PROG_TYPE_CGROUP_SKB:
switch (expected_attach_type) {
case BPF_CGROUP_INET_INGRESS:
case BPF_CGROUP_INET_EGRESS:
return 0;
default:
return -EINVAL;
}
case BPF_PROG_TYPE_CGROUP_SOCKOPT:
switch (expected_attach_type) {
case BPF_CGROUP_SETSOCKOPT:
case BPF_CGROUP_GETSOCKOPT:
return 0;
default:
return -EINVAL;
}
case BPF_PROG_TYPE_SK_LOOKUP:
if (expected_attach_type == BPF_SK_LOOKUP)
return 0;
return -EINVAL;
case BPF_PROG_TYPE_EXT:
if (expected_attach_type)
return -EINVAL;
fallthrough;
default:
return 0;
}
}
static bool is_net_admin_prog_type(enum bpf_prog_type prog_type)
{
switch (prog_type) {
case BPF_PROG_TYPE_SCHED_CLS:
case BPF_PROG_TYPE_SCHED_ACT:
case BPF_PROG_TYPE_XDP:
case BPF_PROG_TYPE_LWT_IN:
case BPF_PROG_TYPE_LWT_OUT:
case BPF_PROG_TYPE_LWT_XMIT:
case BPF_PROG_TYPE_LWT_SEG6LOCAL:
case BPF_PROG_TYPE_SK_SKB:
case BPF_PROG_TYPE_SK_MSG:
case BPF_PROG_TYPE_LIRC_MODE2:
case BPF_PROG_TYPE_FLOW_DISSECTOR:
case BPF_PROG_TYPE_CGROUP_DEVICE:
case BPF_PROG_TYPE_CGROUP_SOCK:
case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
case BPF_PROG_TYPE_CGROUP_SOCKOPT:
case BPF_PROG_TYPE_CGROUP_SYSCTL:
case BPF_PROG_TYPE_SOCK_OPS:
case BPF_PROG_TYPE_EXT: /* extends any prog */
return true;
case BPF_PROG_TYPE_CGROUP_SKB:
/* always unpriv */
case BPF_PROG_TYPE_SK_REUSEPORT:
/* equivalent to SOCKET_FILTER. need CAP_BPF only */
default:
return false;
}
}
static bool is_perfmon_prog_type(enum bpf_prog_type prog_type)
{
switch (prog_type) {
case BPF_PROG_TYPE_KPROBE:
case BPF_PROG_TYPE_TRACEPOINT:
case BPF_PROG_TYPE_PERF_EVENT:
case BPF_PROG_TYPE_RAW_TRACEPOINT:
case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
case BPF_PROG_TYPE_TRACING:
case BPF_PROG_TYPE_LSM:
case BPF_PROG_TYPE_STRUCT_OPS: /* has access to struct sock */
case BPF_PROG_TYPE_EXT: /* extends any prog */
return true;
default:
return false;
}
}
/* last field in 'union bpf_attr' used by this command */
#define BPF_PROG_LOAD_LAST_FIELD attach_prog_fd
static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
{
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;
if (attr->prog_flags & ~(BPF_F_STRICT_ALIGNMENT |
BPF_F_ANY_ALIGNMENT |
BPF_F_TEST_STATE_FREQ |
BPF_F_SLEEPABLE |
BPF_F_TEST_RND_HI32))
return -EINVAL;
if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
(attr->prog_flags & BPF_F_ANY_ALIGNMENT) &&
!bpf_capable())
return -EPERM;
/* 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 == 0 ||
attr->insn_cnt > (bpf_capable() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS))
return -E2BIG;
if (type != BPF_PROG_TYPE_SOCKET_FILTER &&
type != BPF_PROG_TYPE_CGROUP_SKB &&
!bpf_capable())
return -EPERM;
if (is_net_admin_prog_type(type) && !capable(CAP_NET_ADMIN) && !capable(CAP_SYS_ADMIN))
return -EPERM;
if (is_perfmon_prog_type(type) && !perfmon_capable())
return -EPERM;
bpf_prog_load_fixup_attach_type(attr);
if (bpf_prog_load_check_attach(type, attr->expected_attach_type,
attr->attach_btf_id,
attr->attach_prog_fd))
return -EINVAL;
/* plain bpf_prog allocation */
prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
if (!prog)
return -ENOMEM;
prog->expected_attach_type = attr->expected_attach_type;
prog->aux->attach_btf_id = attr->attach_btf_id;
if (attr->attach_prog_fd) {
struct bpf_prog *dst_prog;
dst_prog = bpf_prog_get(attr->attach_prog_fd);
if (IS_ERR(dst_prog)) {
err = PTR_ERR(dst_prog);
goto free_prog_nouncharge;
}
prog->aux->dst_prog = dst_prog;
}
prog->aux->offload_requested = !!attr->prog_ifindex;
prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE;
err = security_bpf_prog_alloc(prog->aux);
if (err)
goto free_prog_nouncharge;
err = bpf_prog_charge_memlock(prog);
if (err)
goto free_prog_sec;
prog->len = attr->insn_cnt;
err = -EFAULT;
if (copy_from_user(prog->insns, u64_to_user_ptr(attr->insns),
bpf_prog_insn_size(prog)) != 0)
goto free_prog;
prog->orig_prog = NULL;
prog->jited = 0;
atomic64_set(&prog->aux->refcnt, 1);
prog->gpl_compatible = is_gpl ? 1 : 0;
if (bpf_prog_is_dev_bound(prog->aux)) {
err = bpf_prog_offload_init(prog, attr);
if (err)
goto free_prog;
}
/* find program type: socket_filter vs tracing_filter */
err = find_prog_type(type, prog);
if (err < 0)
goto free_prog;
prog->aux->load_time = ktime_get_boottime_ns();
err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name,
sizeof(attr->prog_name));
if (err < 0)
goto free_prog;
/* run eBPF verifier */
err = bpf_check(&prog, attr, uattr);
if (err < 0)
goto free_used_maps;
prog = bpf_prog_select_runtime(prog, &err);
if (err < 0)
goto free_used_maps;
err = bpf_prog_alloc_id(prog);
if (err)
goto free_used_maps;
/* Upon success of bpf_prog_alloc_id(), the BPF prog is
* effectively publicly exposed. However, retrieving via
* bpf_prog_get_fd_by_id() will take another reference,
* therefore it cannot be gone underneath us.
*
* Only for the time /after/ successful bpf_prog_new_fd()
* and before returning to userspace, we might just hold
* one reference and any parallel close on that fd could
* rip everything out. Hence, below notifications must
* happen before bpf_prog_new_fd().
*
* Also, any failure handling from this point onwards must
* be using bpf_prog_put() given the program is exposed.
*/
bpf_prog_kallsyms_add(prog);
perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_LOAD, 0);
bpf_audit_prog(prog, BPF_AUDIT_LOAD);
err = bpf_prog_new_fd(prog);
if (err < 0)
bpf_prog_put(prog);
return err;
free_used_maps:
/* In case we have subprogs, we need to wait for a grace
* period before we can tear down JIT memory since symbols
* are already exposed under kallsyms.
*/
__bpf_prog_put_noref(prog, prog->aux->func_cnt);
return err;
free_prog:
bpf_prog_uncharge_memlock(prog);
free_prog_sec:
security_bpf_prog_free(prog->aux);
free_prog_nouncharge:
bpf_prog_free(prog);
return err;
}
#define BPF_OBJ_LAST_FIELD file_flags
static int bpf_obj_pin(const union bpf_attr *attr)
{
if (CHECK_ATTR(BPF_OBJ) || attr->file_flags != 0)
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 ||
attr->file_flags & ~BPF_OBJ_FLAG_MASK)
return -EINVAL;
return bpf_obj_get_user(u64_to_user_ptr(attr->pathname),
attr->file_flags);
}
void bpf_link_init(struct bpf_link *link, enum bpf_link_type type,
const struct bpf_link_ops *ops, struct bpf_prog *prog)
{
atomic64_set(&link->refcnt, 1);
link->type = type;
link->id = 0;
link->ops = ops;
link->prog = prog;
}
static void bpf_link_free_id(int id)
{
if (!id)
return;
spin_lock_bh(&link_idr_lock);
idr_remove(&link_idr, id);
spin_unlock_bh(&link_idr_lock);
}
/* Clean up bpf_link and corresponding anon_inode file and FD. After
* anon_inode is created, bpf_link can't be just kfree()'d due to deferred
* anon_inode's release() call. This helper marksbpf_link as
* defunct, releases anon_inode file and puts reserved FD. bpf_prog's refcnt
* is not decremented, it's the responsibility of a calling code that failed
* to complete bpf_link initialization.
*/
void bpf_link_cleanup(struct bpf_link_primer *primer)
{
primer->link->prog = NULL;
bpf_link_free_id(primer->id);
fput(primer->file);
put_unused_fd(primer->fd);
}
void bpf_link_inc(struct bpf_link *link)
{
atomic64_inc(&link->refcnt);
}
/* bpf_link_free is guaranteed to be called from process context */
static void bpf_link_free(struct bpf_link *link)
{
bpf_link_free_id(link->id);
if (link->prog) {
/* detach BPF program, clean up used resources */
link->ops->release(link);
bpf_prog_put(link->prog);
}
/* free bpf_link and its containing memory */
link->ops->dealloc(link);
}
static void bpf_link_put_deferred(struct work_struct *work)
{
struct bpf_link *link = container_of(work, struct bpf_link, work);
bpf_link_free(link);
}
/* bpf_link_put can be called from atomic context, but ensures that resources
* are freed from process context
*/
void bpf_link_put(struct bpf_link *link)
{
if (!atomic64_dec_and_test(&link->refcnt))
return;
if (in_atomic()) {
INIT_WORK(&link->work, bpf_link_put_deferred);
schedule_work(&link->work);
} else {
bpf_link_free(link);
}
}
static int bpf_link_release(struct inode *inode, struct file *filp)
{
struct bpf_link *link = filp->private_data;
bpf_link_put(link);
return 0;
}
#ifdef CONFIG_PROC_FS
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
#define BPF_MAP_TYPE(_id, _ops)
#define BPF_LINK_TYPE(_id, _name) [_id] = #_name,
static const char *bpf_link_type_strs[] = {
[BPF_LINK_TYPE_UNSPEC] = "<invalid>",
#include <linux/bpf_types.h>
};
#undef BPF_PROG_TYPE
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE
static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp)
{
const struct bpf_link *link = filp->private_data;
const struct bpf_prog *prog = link->prog;
char prog_tag[sizeof(prog->tag) * 2 + 1] = { };
bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
seq_printf(m,
"link_type:\t%s\n"
"link_id:\t%u\n"
"prog_tag:\t%s\n"
"prog_id:\t%u\n",
bpf_link_type_strs[link->type],
link->id,
prog_tag,
prog->aux->id);
if (link->ops->show_fdinfo)
link->ops->show_fdinfo(link, m);
}
#endif
static const struct file_operations bpf_link_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = bpf_link_show_fdinfo,
#endif
.release = bpf_link_release,
.read = bpf_dummy_read,
.write = bpf_dummy_write,
};
static int bpf_link_alloc_id(struct bpf_link *link)
{
int id;
idr_preload(GFP_KERNEL);
spin_lock_bh(&link_idr_lock);
id = idr_alloc_cyclic(&link_idr, link, 1, INT_MAX, GFP_ATOMIC);
spin_unlock_bh(&link_idr_lock);
idr_preload_end();
return id;
}
/* Prepare bpf_link to be exposed to user-space by allocating anon_inode file,
* reserving unused FD and allocating ID from link_idr. This is to be paired
* with bpf_link_settle() to install FD and ID and expose bpf_link to
* user-space, if bpf_link is successfully attached. If not, bpf_link and
* pre-allocated resources are to be freed with bpf_cleanup() call. All the
* transient state is passed around in struct bpf_link_primer.
* This is preferred way to create and initialize bpf_link, especially when
* there are complicated and expensive operations inbetween creating bpf_link
* itself and attaching it to BPF hook. By using bpf_link_prime() and
* bpf_link_settle() kernel code using bpf_link doesn't have to perform
* expensive (and potentially failing) roll back operations in a rare case
* that file, FD, or ID can't be allocated.
*/
int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *primer)
{
struct file *file;
int fd, id;
fd = get_unused_fd_flags(O_CLOEXEC);
if (fd < 0)
return fd;
id = bpf_link_alloc_id(link);
if (id < 0) {
put_unused_fd(fd);
return id;
}
file = anon_inode_getfile("bpf_link", &bpf_link_fops, link, O_CLOEXEC);
if (IS_ERR(file)) {
bpf_link_free_id(id);
put_unused_fd(fd);
return PTR_ERR(file);
}
primer->link = link;
primer->file = file;
primer->fd = fd;
primer->id = id;
return 0;
}
int bpf_link_settle(struct bpf_link_primer *primer)
{
/* make bpf_link fetchable by ID */
spin_lock_bh(&link_idr_lock);
primer->link->id = primer->id;
spin_unlock_bh(&link_idr_lock);
/* make bpf_link fetchable by FD */
fd_install(primer->fd, primer->file);
/* pass through installed FD */
return primer->fd;
}
int bpf_link_new_fd(struct bpf_link *link)
{
return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC);
}
struct bpf_link *bpf_link_get_from_fd(u32 ufd)
{
struct fd f = fdget(ufd);
struct bpf_link *link;
if (!f.file)
return ERR_PTR(-EBADF);
if (f.file->f_op != &bpf_link_fops) {
fdput(f);
return ERR_PTR(-EINVAL);
}
link = f.file->private_data;
bpf_link_inc(link);
fdput(f);
return link;
}
struct bpf_tracing_link {
struct bpf_link link;
enum bpf_attach_type attach_type;
struct bpf_trampoline *trampoline;
struct bpf_prog *tgt_prog;
};
static void bpf_tracing_link_release(struct bpf_link *link)
{
struct bpf_tracing_link *tr_link =
container_of(link, struct bpf_tracing_link, link);
WARN_ON_ONCE(bpf_trampoline_unlink_prog(link->prog,
tr_link->trampoline));
bpf_trampoline_put(tr_link->trampoline);
/* tgt_prog is NULL if target is a kernel function */
if (tr_link->tgt_prog)
bpf_prog_put(tr_link->tgt_prog);
}
static void bpf_tracing_link_dealloc(struct bpf_link *link)
{
struct bpf_tracing_link *tr_link =
container_of(link, struct bpf_tracing_link, link);
kfree(tr_link);
}
static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link,
struct seq_file *seq)
{
struct bpf_tracing_link *tr_link =
container_of(link, struct bpf_tracing_link, link);
seq_printf(seq,
"attach_type:\t%d\n",
tr_link->attach_type);
}
static int bpf_tracing_link_fill_link_info(const struct bpf_link *link,
struct bpf_link_info *info)
{
struct bpf_tracing_link *tr_link =
container_of(link, struct bpf_tracing_link, link);
info->tracing.attach_type = tr_link->attach_type;
return 0;
}
static const struct bpf_link_ops bpf_tracing_link_lops = {
.release = bpf_tracing_link_release,
.dealloc = bpf_tracing_link_dealloc,
.show_fdinfo = bpf_tracing_link_show_fdinfo,
.fill_link_info = bpf_tracing_link_fill_link_info,
};
static int bpf_tracing_prog_attach(struct bpf_prog *prog,
int tgt_prog_fd,
u32 btf_id)
{
struct bpf_link_primer link_primer;
struct bpf_prog *tgt_prog = NULL;
struct bpf_trampoline *tr = NULL;
struct bpf_tracing_link *link;
u64 key = 0;
int err;
switch (prog->type) {
case BPF_PROG_TYPE_TRACING:
if (prog->expected_attach_type != BPF_TRACE_FENTRY &&
prog->expected_attach_type != BPF_TRACE_FEXIT &&
prog->expected_attach_type != BPF_MODIFY_RETURN) {
err = -EINVAL;
goto out_put_prog;
}
break;
case BPF_PROG_TYPE_EXT:
if (prog->expected_attach_type != 0) {
err = -EINVAL;
goto out_put_prog;
}
break;
case BPF_PROG_TYPE_LSM:
if (prog->expected_attach_type != BPF_LSM_MAC) {
err = -EINVAL;
goto out_put_prog;
}
break;
default:
err = -EINVAL;
goto out_put_prog;
}
if (!!tgt_prog_fd != !!btf_id) {
err = -EINVAL;
goto out_put_prog;
}
if (tgt_prog_fd) {
/* For now we only allow new targets for BPF_PROG_TYPE_EXT */
if (prog->type != BPF_PROG_TYPE_EXT) {
err = -EINVAL;
goto out_put_prog;
}
tgt_prog = bpf_prog_get(tgt_prog_fd);
if (IS_ERR(tgt_prog)) {
err = PTR_ERR(tgt_prog);
tgt_prog = NULL;
goto out_put_prog;
}
key = bpf_trampoline_compute_key(tgt_prog, btf_id);
}
link = kzalloc(sizeof(*link), GFP_USER);
if (!link) {
err = -ENOMEM;
goto out_put_prog;
}
bpf_link_init(&link->link, BPF_LINK_TYPE_TRACING,
&bpf_tracing_link_lops, prog);
link->attach_type = prog->expected_attach_type;
mutex_lock(&prog->aux->dst_mutex);
/* There are a few possible cases here:
*
* - if prog->aux->dst_trampoline is set, the program was just loaded
* and not yet attached to anything, so we can use the values stored
* in prog->aux
*
* - if prog->aux->dst_trampoline is NULL, the program has already been
* attached to a target and its initial target was cleared (below)
*
* - if tgt_prog != NULL, the caller specified tgt_prog_fd +
* target_btf_id using the link_create API.
*
* - if tgt_prog == NULL when this function was called using the old
* raw_tracepoint_open API, and we need a target from prog->aux
*
* The combination of no saved target in prog->aux, and no target
* specified on load is illegal, and we reject that here.
*/
if (!prog->aux->dst_trampoline && !tgt_prog) {
err = -ENOENT;
goto out_unlock;
}
if (!prog->aux->dst_trampoline ||
(key && key != prog->aux->dst_trampoline->key)) {
/* If there is no saved target, or the specified target is
* different from the destination specified at load time, we
* need a new trampoline and a check for compatibility
*/
struct bpf_attach_target_info tgt_info = {};
err = bpf_check_attach_target(NULL, prog, tgt_prog, btf_id,
&tgt_info);
if (err)
goto out_unlock;
tr = bpf_trampoline_get(key, &tgt_info);
if (!tr) {
err = -ENOMEM;
goto out_unlock;
}
} else {
/* The caller didn't specify a target, or the target was the
* same as the destination supplied during program load. This
* means we can reuse the trampoline and reference from program
* load time, and there is no need to allocate a new one. This
* can only happen once for any program, as the saved values in
* prog->aux are cleared below.
*/
tr = prog->aux->dst_trampoline;
tgt_prog = prog->aux->dst_prog;
}
err = bpf_link_prime(&link->link, &link_primer);
if (err)
goto out_unlock;
err = bpf_trampoline_link_prog(prog, tr);
if (err) {
bpf_link_cleanup(&link_primer);
link = NULL;
goto out_unlock;
}
link->tgt_prog = tgt_prog;
link->trampoline = tr;
/* Always clear the trampoline and target prog from prog->aux to make
* sure the original attach destination is not kept alive after a
* program is (re-)attached to another target.
*/
if (prog->aux->dst_prog &&
(tgt_prog_fd || tr != prog->aux->dst_trampoline))
/* got extra prog ref from syscall, or attaching to different prog */
bpf_prog_put(prog->aux->dst_prog);
if (prog->aux->dst_trampoline && tr != prog->aux->dst_trampoline)
/* we allocated a new trampoline, so free the old one */
bpf_trampoline_put(prog->aux->dst_trampoline);
prog->aux->dst_prog = NULL;
prog->aux->dst_trampoline = NULL;
mutex_unlock(&prog->aux->dst_mutex);
return bpf_link_settle(&link_primer);
out_unlock:
if (tr && tr != prog->aux->dst_trampoline)
bpf_trampoline_put(tr);
mutex_unlock(&prog->aux->dst_mutex);
kfree(link);
out_put_prog:
if (tgt_prog_fd && tgt_prog)
bpf_prog_put(tgt_prog);
return err;
}
struct bpf_raw_tp_link {
struct bpf_link link;
struct bpf_raw_event_map *btp;
};
static void bpf_raw_tp_link_release(struct bpf_link *link)
{
struct bpf_raw_tp_link *raw_tp =
container_of(link, struct bpf_raw_tp_link, link);
bpf_probe_unregister(raw_tp->btp, raw_tp->link.prog);
bpf_put_raw_tracepoint(raw_tp->btp);
}
static void bpf_raw_tp_link_dealloc(struct bpf_link *link)
{
struct bpf_raw_tp_link *raw_tp =
container_of(link, struct bpf_raw_tp_link, link);
kfree(raw_tp);
}
static void bpf_raw_tp_link_show_fdinfo(const struct bpf_link *link,
struct seq_file *seq)
{
struct bpf_raw_tp_link *raw_tp_link =
container_of(link, struct bpf_raw_tp_link, link);
seq_printf(seq,
"tp_name:\t%s\n",
raw_tp_link->btp->tp->name);
}
static int bpf_raw_tp_link_fill_link_info(const struct bpf_link *link,
struct bpf_link_info *info)
{
struct bpf_raw_tp_link *raw_tp_link =
container_of(link, struct bpf_raw_tp_link, link);
char __user *ubuf = u64_to_user_ptr(info->raw_tracepoint.tp_name);
const char *tp_name = raw_tp_link->btp->tp->name;
u32 ulen = info->raw_tracepoint.tp_name_len;
size_t tp_len = strlen(tp_name);
if (!ulen ^ !ubuf)
return -EINVAL;
info->raw_tracepoint.tp_name_len = tp_len + 1;
if (!ubuf)
return 0;
if (ulen >= tp_len + 1) {
if (copy_to_user(ubuf, tp_name, tp_len + 1))