blob: 315053ef6a7503beaedf48e53fdc8e53b33f2974 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*/
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/bpf-cgroup.h>
#include <linux/rcupdate.h>
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/topology.h>
#include <linux/ktime.h>
#include <linux/sched.h>
#include <linux/uidgid.h>
#include <linux/filter.h>
#include <linux/ctype.h>
#include <linux/jiffies.h>
#include <linux/pid_namespace.h>
#include <linux/proc_ns.h>
#include <linux/security.h>
#include <linux/btf_ids.h>
#include "../../lib/kstrtox.h"
/* If kernel subsystem is allowing eBPF programs to call this function,
* inside its own verifier_ops->get_func_proto() callback it should return
* bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
*
* Different map implementations will rely on rcu in map methods
* lookup/update/delete, therefore eBPF programs must run under rcu lock
* if program is allowed to access maps, so check rcu_read_lock_held in
* all three functions.
*/
BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
{
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
return (unsigned long) map->ops->map_lookup_elem(map, key);
}
const struct bpf_func_proto bpf_map_lookup_elem_proto = {
.func = bpf_map_lookup_elem,
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_MAP_KEY,
};
BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
void *, value, u64, flags)
{
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
return map->ops->map_update_elem(map, key, value, flags);
}
const struct bpf_func_proto bpf_map_update_elem_proto = {
.func = bpf_map_update_elem,
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_MAP_KEY,
.arg3_type = ARG_PTR_TO_MAP_VALUE,
.arg4_type = ARG_ANYTHING,
};
BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
{
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
return map->ops->map_delete_elem(map, key);
}
const struct bpf_func_proto bpf_map_delete_elem_proto = {
.func = bpf_map_delete_elem,
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_MAP_KEY,
};
BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags)
{
return map->ops->map_push_elem(map, value, flags);
}
const struct bpf_func_proto bpf_map_push_elem_proto = {
.func = bpf_map_push_elem,
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_MAP_VALUE,
.arg3_type = ARG_ANYTHING,
};
BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
{
return map->ops->map_pop_elem(map, value);
}
const struct bpf_func_proto bpf_map_pop_elem_proto = {
.func = bpf_map_pop_elem,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE,
};
BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value)
{
return map->ops->map_peek_elem(map, value);
}
const struct bpf_func_proto bpf_map_peek_elem_proto = {
.func = bpf_map_peek_elem,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE,
};
const struct bpf_func_proto bpf_get_prandom_u32_proto = {
.func = bpf_user_rnd_u32,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_0(bpf_get_smp_processor_id)
{
return smp_processor_id();
}
const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
.func = bpf_get_smp_processor_id,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_0(bpf_get_numa_node_id)
{
return numa_node_id();
}
const struct bpf_func_proto bpf_get_numa_node_id_proto = {
.func = bpf_get_numa_node_id,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_0(bpf_ktime_get_ns)
{
/* NMI safe access to clock monotonic */
return ktime_get_mono_fast_ns();
}
const struct bpf_func_proto bpf_ktime_get_ns_proto = {
.func = bpf_ktime_get_ns,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_0(bpf_ktime_get_boot_ns)
{
/* NMI safe access to clock boottime */
return ktime_get_boot_fast_ns();
}
const struct bpf_func_proto bpf_ktime_get_boot_ns_proto = {
.func = bpf_ktime_get_boot_ns,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_0(bpf_ktime_get_coarse_ns)
{
return ktime_get_coarse_ns();
}
const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto = {
.func = bpf_ktime_get_coarse_ns,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_0(bpf_get_current_pid_tgid)
{
struct task_struct *task = current;
if (unlikely(!task))
return -EINVAL;
return (u64) task->tgid << 32 | task->pid;
}
const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
.func = bpf_get_current_pid_tgid,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_0(bpf_get_current_uid_gid)
{
struct task_struct *task = current;
kuid_t uid;
kgid_t gid;
if (unlikely(!task))
return -EINVAL;
current_uid_gid(&uid, &gid);
return (u64) from_kgid(&init_user_ns, gid) << 32 |
from_kuid(&init_user_ns, uid);
}
const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
.func = bpf_get_current_uid_gid,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
{
struct task_struct *task = current;
if (unlikely(!task))
goto err_clear;
/* Verifier guarantees that size > 0 */
strscpy(buf, task->comm, size);
return 0;
err_clear:
memset(buf, 0, size);
return -EINVAL;
}
const struct bpf_func_proto bpf_get_current_comm_proto = {
.func = bpf_get_current_comm,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_UNINIT_MEM,
.arg2_type = ARG_CONST_SIZE,
};
#if defined(CONFIG_QUEUED_SPINLOCKS) || defined(CONFIG_BPF_ARCH_SPINLOCK)
static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
{
arch_spinlock_t *l = (void *)lock;
union {
__u32 val;
arch_spinlock_t lock;
} u = { .lock = __ARCH_SPIN_LOCK_UNLOCKED };
compiletime_assert(u.val == 0, "__ARCH_SPIN_LOCK_UNLOCKED not 0");
BUILD_BUG_ON(sizeof(*l) != sizeof(__u32));
BUILD_BUG_ON(sizeof(*lock) != sizeof(__u32));
arch_spin_lock(l);
}
static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
{
arch_spinlock_t *l = (void *)lock;
arch_spin_unlock(l);
}
#else
static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
{
atomic_t *l = (void *)lock;
BUILD_BUG_ON(sizeof(*l) != sizeof(*lock));
do {
atomic_cond_read_relaxed(l, !VAL);
} while (atomic_xchg(l, 1));
}
static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
{
atomic_t *l = (void *)lock;
atomic_set_release(l, 0);
}
#endif
static DEFINE_PER_CPU(unsigned long, irqsave_flags);
static inline void __bpf_spin_lock_irqsave(struct bpf_spin_lock *lock)
{
unsigned long flags;
local_irq_save(flags);
__bpf_spin_lock(lock);
__this_cpu_write(irqsave_flags, flags);
}
notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock)
{
__bpf_spin_lock_irqsave(lock);
return 0;
}
const struct bpf_func_proto bpf_spin_lock_proto = {
.func = bpf_spin_lock,
.gpl_only = false,
.ret_type = RET_VOID,
.arg1_type = ARG_PTR_TO_SPIN_LOCK,
};
static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock)
{
unsigned long flags;
flags = __this_cpu_read(irqsave_flags);
__bpf_spin_unlock(lock);
local_irq_restore(flags);
}
notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock)
{
__bpf_spin_unlock_irqrestore(lock);
return 0;
}
const struct bpf_func_proto bpf_spin_unlock_proto = {
.func = bpf_spin_unlock,
.gpl_only = false,
.ret_type = RET_VOID,
.arg1_type = ARG_PTR_TO_SPIN_LOCK,
};
void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
bool lock_src)
{
struct bpf_spin_lock *lock;
if (lock_src)
lock = src + map->spin_lock_off;
else
lock = dst + map->spin_lock_off;
preempt_disable();
__bpf_spin_lock_irqsave(lock);
copy_map_value(map, dst, src);
__bpf_spin_unlock_irqrestore(lock);
preempt_enable();
}
BPF_CALL_0(bpf_jiffies64)
{
return get_jiffies_64();
}
const struct bpf_func_proto bpf_jiffies64_proto = {
.func = bpf_jiffies64,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
#ifdef CONFIG_CGROUPS
BPF_CALL_0(bpf_get_current_cgroup_id)
{
struct cgroup *cgrp;
u64 cgrp_id;
rcu_read_lock();
cgrp = task_dfl_cgroup(current);
cgrp_id = cgroup_id(cgrp);
rcu_read_unlock();
return cgrp_id;
}
const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
.func = bpf_get_current_cgroup_id,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_1(bpf_get_current_ancestor_cgroup_id, int, ancestor_level)
{
struct cgroup *cgrp;
struct cgroup *ancestor;
u64 cgrp_id;
rcu_read_lock();
cgrp = task_dfl_cgroup(current);
ancestor = cgroup_ancestor(cgrp, ancestor_level);
cgrp_id = ancestor ? cgroup_id(ancestor) : 0;
rcu_read_unlock();
return cgrp_id;
}
const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = {
.func = bpf_get_current_ancestor_cgroup_id,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_ANYTHING,
};
#ifdef CONFIG_CGROUP_BPF
BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
{
/* flags argument is not used now,
* but provides an ability to extend the API.
* verifier checks that its value is correct.
*/
enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
struct bpf_cgroup_storage *storage;
struct bpf_cg_run_ctx *ctx;
void *ptr;
/* get current cgroup storage from BPF run context */
ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
storage = ctx->prog_item->cgroup_storage[stype];
if (stype == BPF_CGROUP_STORAGE_SHARED)
ptr = &READ_ONCE(storage->buf)->data[0];
else
ptr = this_cpu_ptr(storage->percpu_buf);
return (unsigned long)ptr;
}
const struct bpf_func_proto bpf_get_local_storage_proto = {
.func = bpf_get_local_storage,
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_ANYTHING,
};
#endif
#define BPF_STRTOX_BASE_MASK 0x1F
static int __bpf_strtoull(const char *buf, size_t buf_len, u64 flags,
unsigned long long *res, bool *is_negative)
{
unsigned int base = flags & BPF_STRTOX_BASE_MASK;
const char *cur_buf = buf;
size_t cur_len = buf_len;
unsigned int consumed;
size_t val_len;
char str[64];
if (!buf || !buf_len || !res || !is_negative)
return -EINVAL;
if (base != 0 && base != 8 && base != 10 && base != 16)
return -EINVAL;
if (flags & ~BPF_STRTOX_BASE_MASK)
return -EINVAL;
while (cur_buf < buf + buf_len && isspace(*cur_buf))
++cur_buf;
*is_negative = (cur_buf < buf + buf_len && *cur_buf == '-');
if (*is_negative)
++cur_buf;
consumed = cur_buf - buf;
cur_len -= consumed;
if (!cur_len)
return -EINVAL;
cur_len = min(cur_len, sizeof(str) - 1);
memcpy(str, cur_buf, cur_len);
str[cur_len] = '\0';
cur_buf = str;
cur_buf = _parse_integer_fixup_radix(cur_buf, &base);
val_len = _parse_integer(cur_buf, base, res);
if (val_len & KSTRTOX_OVERFLOW)
return -ERANGE;
if (val_len == 0)
return -EINVAL;
cur_buf += val_len;
consumed += cur_buf - str;
return consumed;
}
static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags,
long long *res)
{
unsigned long long _res;
bool is_negative;
int err;
err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
if (err < 0)
return err;
if (is_negative) {
if ((long long)-_res > 0)
return -ERANGE;
*res = -_res;
} else {
if ((long long)_res < 0)
return -ERANGE;
*res = _res;
}
return err;
}
BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags,
long *, res)
{
long long _res;
int err;
err = __bpf_strtoll(buf, buf_len, flags, &_res);
if (err < 0)
return err;
if (_res != (long)_res)
return -ERANGE;
*res = _res;
return err;
}
const struct bpf_func_proto bpf_strtol_proto = {
.func = bpf_strtol,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
.arg2_type = ARG_CONST_SIZE,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_PTR_TO_LONG,
};
BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags,
unsigned long *, res)
{
unsigned long long _res;
bool is_negative;
int err;
err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
if (err < 0)
return err;
if (is_negative)
return -EINVAL;
if (_res != (unsigned long)_res)
return -ERANGE;
*res = _res;
return err;
}
const struct bpf_func_proto bpf_strtoul_proto = {
.func = bpf_strtoul,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
.arg2_type = ARG_CONST_SIZE,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_PTR_TO_LONG,
};
#endif
BPF_CALL_3(bpf_strncmp, const char *, s1, u32, s1_sz, const char *, s2)
{
return strncmp(s1, s2, s1_sz);
}
const struct bpf_func_proto bpf_strncmp_proto = {
.func = bpf_strncmp,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_MEM,
.arg2_type = ARG_CONST_SIZE,
.arg3_type = ARG_PTR_TO_CONST_STR,
};
BPF_CALL_4(bpf_get_ns_current_pid_tgid, u64, dev, u64, ino,
struct bpf_pidns_info *, nsdata, u32, size)
{
struct task_struct *task = current;
struct pid_namespace *pidns;
int err = -EINVAL;
if (unlikely(size != sizeof(struct bpf_pidns_info)))
goto clear;
if (unlikely((u64)(dev_t)dev != dev))
goto clear;
if (unlikely(!task))
goto clear;
pidns = task_active_pid_ns(task);
if (unlikely(!pidns)) {
err = -ENOENT;
goto clear;
}
if (!ns_match(&pidns->ns, (dev_t)dev, ino))
goto clear;
nsdata->pid = task_pid_nr_ns(task, pidns);
nsdata->tgid = task_tgid_nr_ns(task, pidns);
return 0;
clear:
memset((void *)nsdata, 0, (size_t) size);
return err;
}
const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto = {
.func = bpf_get_ns_current_pid_tgid,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_ANYTHING,
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_PTR_TO_UNINIT_MEM,
.arg4_type = ARG_CONST_SIZE,
};
static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {
.func = bpf_get_raw_cpu_id,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map,
u64, flags, void *, data, u64, size)
{
if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
return -EINVAL;
return bpf_event_output(map, flags, data, size, NULL, 0, NULL);
}
const struct bpf_func_proto bpf_event_output_data_proto = {
.func = bpf_event_output_data,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY,
.arg5_type = ARG_CONST_SIZE_OR_ZERO,
};
BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size,
const void __user *, user_ptr)
{
int ret = copy_from_user(dst, user_ptr, size);
if (unlikely(ret)) {
memset(dst, 0, size);
ret = -EFAULT;
}
return ret;
}
const struct bpf_func_proto bpf_copy_from_user_proto = {
.func = bpf_copy_from_user,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_UNINIT_MEM,
.arg2_type = ARG_CONST_SIZE_OR_ZERO,
.arg3_type = ARG_ANYTHING,
};
BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size,
const void __user *, user_ptr, struct task_struct *, tsk, u64, flags)
{
int ret;
/* flags is not used yet */
if (unlikely(flags))
return -EINVAL;
if (unlikely(!size))
return 0;
ret = access_process_vm(tsk, (unsigned long)user_ptr, dst, size, 0);
if (ret == size)
return 0;
memset(dst, 0, size);
/* Return -EFAULT for partial read */
return ret < 0 ? ret : -EFAULT;
}
const struct bpf_func_proto bpf_copy_from_user_task_proto = {
.func = bpf_copy_from_user_task,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_UNINIT_MEM,
.arg2_type = ARG_CONST_SIZE_OR_ZERO,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_PTR_TO_BTF_ID,
.arg4_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
.arg5_type = ARG_ANYTHING
};
BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
{
if (cpu >= nr_cpu_ids)
return (unsigned long)NULL;
return (unsigned long)per_cpu_ptr((const void __percpu *)ptr, cpu);
}
const struct bpf_func_proto bpf_per_cpu_ptr_proto = {
.func = bpf_per_cpu_ptr,
.gpl_only = false,
.ret_type = RET_PTR_TO_MEM_OR_BTF_ID | PTR_MAYBE_NULL | MEM_RDONLY,
.arg1_type = ARG_PTR_TO_PERCPU_BTF_ID,
.arg2_type = ARG_ANYTHING,
};
BPF_CALL_1(bpf_this_cpu_ptr, const void *, percpu_ptr)
{
return (unsigned long)this_cpu_ptr((const void __percpu *)percpu_ptr);
}
const struct bpf_func_proto bpf_this_cpu_ptr_proto = {
.func = bpf_this_cpu_ptr,
.gpl_only = false,
.ret_type = RET_PTR_TO_MEM_OR_BTF_ID | MEM_RDONLY,
.arg1_type = ARG_PTR_TO_PERCPU_BTF_ID,
};
static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
size_t bufsz)
{
void __user *user_ptr = (__force void __user *)unsafe_ptr;
buf[0] = 0;
switch (fmt_ptype) {
case 's':
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
if ((unsigned long)unsafe_ptr < TASK_SIZE)
return strncpy_from_user_nofault(buf, user_ptr, bufsz);
fallthrough;
#endif
case 'k':
return strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
case 'u':
return strncpy_from_user_nofault(buf, user_ptr, bufsz);
}
return -EINVAL;
}
/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
* arguments representation.
*/
#define MAX_BPRINTF_BUF_LEN 512
/* Support executing three nested bprintf helper calls on a given CPU */
#define MAX_BPRINTF_NEST_LEVEL 3
struct bpf_bprintf_buffers {
char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
};
static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
static int try_get_fmt_tmp_buf(char **tmp_buf)
{
struct bpf_bprintf_buffers *bufs;
int nest_level;
preempt_disable();
nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
this_cpu_dec(bpf_bprintf_nest_level);
preempt_enable();
return -EBUSY;
}
bufs = this_cpu_ptr(&bpf_bprintf_bufs);
*tmp_buf = bufs->tmp_bufs[nest_level - 1];
return 0;
}
void bpf_bprintf_cleanup(void)
{
if (this_cpu_read(bpf_bprintf_nest_level)) {
this_cpu_dec(bpf_bprintf_nest_level);
preempt_enable();
}
}
/*
* bpf_bprintf_prepare - Generic pass on format strings for bprintf-like helpers
*
* Returns a negative value if fmt is an invalid format string or 0 otherwise.
*
* This can be used in two ways:
* - Format string verification only: when bin_args is NULL
* - Arguments preparation: in addition to the above verification, it writes in
* bin_args a binary representation of arguments usable by bstr_printf where
* pointers from BPF have been sanitized.
*
* In argument preparation mode, if 0 is returned, safe temporary buffers are
* allocated and bpf_bprintf_cleanup should be called to free them after use.
*/
int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
u32 **bin_args, u32 num_args)
{
char *unsafe_ptr = NULL, *tmp_buf = NULL, *tmp_buf_end, *fmt_end;
size_t sizeof_cur_arg, sizeof_cur_ip;
int err, i, num_spec = 0;
u64 cur_arg;
char fmt_ptype, cur_ip[16], ip_spec[] = "%pXX";
fmt_end = strnchr(fmt, fmt_size, 0);
if (!fmt_end)
return -EINVAL;
fmt_size = fmt_end - fmt;
if (bin_args) {
if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
return -EBUSY;
tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
*bin_args = (u32 *)tmp_buf;
}
for (i = 0; i < fmt_size; i++) {
if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
err = -EINVAL;
goto out;
}
if (fmt[i] != '%')
continue;
if (fmt[i + 1] == '%') {
i++;
continue;
}
if (num_spec >= num_args) {
err = -EINVAL;
goto out;
}
/* The string is zero-terminated so if fmt[i] != 0, we can
* always access fmt[i + 1], in the worst case it will be a 0
*/
i++;
/* skip optional "[0 +-][num]" width formatting field */
while (fmt[i] == '0' || fmt[i] == '+' || fmt[i] == '-' ||
fmt[i] == ' ')
i++;
if (fmt[i] >= '1' && fmt[i] <= '9') {
i++;
while (fmt[i] >= '0' && fmt[i] <= '9')
i++;
}
if (fmt[i] == 'p') {
sizeof_cur_arg = sizeof(long);
if ((fmt[i + 1] == 'k' || fmt[i + 1] == 'u') &&
fmt[i + 2] == 's') {
fmt_ptype = fmt[i + 1];
i += 2;
goto fmt_str;
}
if (fmt[i + 1] == 0 || isspace(fmt[i + 1]) ||
ispunct(fmt[i + 1]) || fmt[i + 1] == 'K' ||
fmt[i + 1] == 'x' || fmt[i + 1] == 's' ||
fmt[i + 1] == 'S') {
/* just kernel pointers */
if (tmp_buf)
cur_arg = raw_args[num_spec];
i++;
goto nocopy_fmt;
}
if (fmt[i + 1] == 'B') {
if (tmp_buf) {
err = snprintf(tmp_buf,
(tmp_buf_end - tmp_buf),
"%pB",
(void *)(long)raw_args[num_spec]);
tmp_buf += (err + 1);
}
i++;
num_spec++;
continue;
}
/* only support "%pI4", "%pi4", "%pI6" and "%pi6". */
if ((fmt[i + 1] != 'i' && fmt[i + 1] != 'I') ||
(fmt[i + 2] != '4' && fmt[i + 2] != '6')) {
err = -EINVAL;
goto out;
}
i += 2;
if (!tmp_buf)
goto nocopy_fmt;
sizeof_cur_ip = (fmt[i] == '4') ? 4 : 16;
if (tmp_buf_end - tmp_buf < sizeof_cur_ip) {
err = -ENOSPC;
goto out;
}
unsafe_ptr = (char *)(long)raw_args[num_spec];
err = copy_from_kernel_nofault(cur_ip, unsafe_ptr,
sizeof_cur_ip);
if (err < 0)
memset(cur_ip, 0, sizeof_cur_ip);
/* hack: bstr_printf expects IP addresses to be
* pre-formatted as strings, ironically, the easiest way
* to do that is to call snprintf.
*/
ip_spec[2] = fmt[i - 1];
ip_spec[3] = fmt[i];
err = snprintf(tmp_buf, tmp_buf_end - tmp_buf,
ip_spec, &cur_ip);
tmp_buf += err + 1;
num_spec++;
continue;
} else if (fmt[i] == 's') {
fmt_ptype = fmt[i];
fmt_str:
if (fmt[i + 1] != 0 &&
!isspace(fmt[i + 1]) &&
!ispunct(fmt[i + 1])) {
err = -EINVAL;
goto out;
}
if (!tmp_buf)
goto nocopy_fmt;
if (tmp_buf_end == tmp_buf) {
err = -ENOSPC;
goto out;
}
unsafe_ptr = (char *)(long)raw_args[num_spec];
err = bpf_trace_copy_string(tmp_buf, unsafe_ptr,
fmt_ptype,
tmp_buf_end - tmp_buf);
if (err < 0) {
tmp_buf[0] = '\0';
err = 1;
}
tmp_buf += err;
num_spec++;
continue;
} else if (fmt[i] == 'c') {
if (!tmp_buf)
goto nocopy_fmt;
if (tmp_buf_end == tmp_buf) {
err = -ENOSPC;
goto out;
}
*tmp_buf = raw_args[num_spec];
tmp_buf++;
num_spec++;
continue;
}
sizeof_cur_arg = sizeof(int);
if (fmt[i] == 'l') {
sizeof_cur_arg = sizeof(long);
i++;
}
if (fmt[i] == 'l') {
sizeof_cur_arg = sizeof(long long);
i++;
}
if (fmt[i] != 'i' && fmt[i] != 'd' && fmt[i] != 'u' &&
fmt[i] != 'x' && fmt[i] != 'X') {
err = -EINVAL;
goto out;
}
if (tmp_buf)
cur_arg = raw_args[num_spec];
nocopy_fmt:
if (tmp_buf) {
tmp_buf = PTR_ALIGN(tmp_buf, sizeof(u32));
if (tmp_buf_end - tmp_buf < sizeof_cur_arg) {
err = -ENOSPC;
goto out;
}
if (sizeof_cur_arg == 8) {
*(u32 *)tmp_buf = *(u32 *)&cur_arg;
*(u32 *)(tmp_buf + 4) = *((u32 *)&cur_arg + 1);
} else {
*(u32 *)tmp_buf = (u32)(long)cur_arg;
}
tmp_buf += sizeof_cur_arg;
}
num_spec++;
}
err = 0;
out:
if (err)
bpf_bprintf_cleanup();
return err;
}
BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
const void *, data, u32, data_len)
{
int err, num_args;
u32 *bin_args;
if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
(data_len && !data))
return -EINVAL;
num_args = data_len / 8;
/* ARG_PTR_TO_CONST_STR guarantees that fmt is zero-terminated so we
* can safely give an unbounded size.
*/
err = bpf_bprintf_prepare(fmt, UINT_MAX, data, &bin_args, num_args);
if (err < 0)
return err;
err = bstr_printf(str, str_size, fmt, bin_args);
bpf_bprintf_cleanup();
return err + 1;
}
const struct bpf_func_proto bpf_snprintf_proto = {
.func = bpf_snprintf,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_MEM_OR_NULL,
.arg2_type = ARG_CONST_SIZE_OR_ZERO,
.arg3_type = ARG_PTR_TO_CONST_STR,
.arg4_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY,
.arg5_type = ARG_CONST_SIZE_OR_ZERO,
};
/* BPF map elements can contain 'struct bpf_timer'.
* Such map owns all of its BPF timers.
* 'struct bpf_timer' is allocated as part of map element allocation
* and it's zero initialized.
* That space is used to keep 'struct bpf_timer_kern'.
* bpf_timer_init() allocates 'struct bpf_hrtimer', inits hrtimer, and
* remembers 'struct bpf_map *' pointer it's part of.
* bpf_timer_set_callback() increments prog refcnt and assign bpf callback_fn.
* bpf_timer_start() arms the timer.
* If user space reference to a map goes to zero at this point
* ops->map_release_uref callback is responsible for cancelling the timers,
* freeing their memory, and decrementing prog's refcnts.
* bpf_timer_cancel() cancels the timer and decrements prog's refcnt.
* Inner maps can contain bpf timers as well. ops->map_release_uref is
* freeing the timers when inner map is replaced or deleted by user space.
*/
struct bpf_hrtimer {
struct hrtimer timer;
struct bpf_map *map;
struct bpf_prog *prog;
void __rcu *callback_fn;
void *value;
};
/* the actual struct hidden inside uapi struct bpf_timer */
struct bpf_timer_kern {
struct bpf_hrtimer *timer;
/* bpf_spin_lock is used here instead of spinlock_t to make
* sure that it always fits into space reserved by struct bpf_timer
* regardless of LOCKDEP and spinlock debug flags.
*/
struct bpf_spin_lock lock;
} __attribute__((aligned(8)));
static DEFINE_PER_CPU(struct bpf_hrtimer *, hrtimer_running);
static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer)
{
struct bpf_hrtimer *t = container_of(hrtimer, struct bpf_hrtimer, timer);
struct bpf_map *map = t->map;
void *value = t->value;
bpf_callback_t callback_fn;
void *key;
u32 idx;
BTF_TYPE_EMIT(struct bpf_timer);
callback_fn = rcu_dereference_check(t->callback_fn, rcu_read_lock_bh_held());
if (!callback_fn)
goto out;
/* bpf_timer_cb() runs in hrtimer_run_softirq. It doesn't migrate and
* cannot be preempted by another bpf_timer_cb() on the same cpu.
* Remember the timer this callback is servicing to prevent
* deadlock if callback_fn() calls bpf_timer_cancel() or
* bpf_map_delete_elem() on the same timer.
*/
this_cpu_write(hrtimer_running, t);
if (map->map_type == BPF_MAP_TYPE_ARRAY) {
struct bpf_array *array = container_of(map, struct bpf_array, map);
/* compute the key */
idx = ((char *)value - array->value) / array->elem_size;
key = &idx;
} else { /* hash or lru */
key = value - round_up(map->key_size, 8);
}
callback_fn((u64)(long)map, (u64)(long)key, (u64)(long)value, 0, 0);
/* The verifier checked that return value is zero. */
this_cpu_write(hrtimer_running, NULL);
out:
return HRTIMER_NORESTART;
}
BPF_CALL_3(bpf_timer_init, struct bpf_timer_kern *, timer, struct bpf_map *, map,
u64, flags)
{
clockid_t clockid = flags & (MAX_CLOCKS - 1);
struct bpf_hrtimer *t;
int ret = 0;
BUILD_BUG_ON(MAX_CLOCKS != 16);
BUILD_BUG_ON(sizeof(struct bpf_timer_kern) > sizeof(struct bpf_timer));
BUILD_BUG_ON(__alignof__(struct bpf_timer_kern) != __alignof__(struct bpf_timer));
if (in_nmi())
return -EOPNOTSUPP;
if (flags >= MAX_CLOCKS ||
/* similar to timerfd except _ALARM variants are not supported */
(clockid != CLOCK_MONOTONIC &&
clockid != CLOCK_REALTIME &&
clockid != CLOCK_BOOTTIME))
return -EINVAL;
__bpf_spin_lock_irqsave(&timer->lock);
t = timer->timer;
if (t) {
ret = -EBUSY;
goto out;
}
if (!atomic64_read(&map->usercnt)) {
/* maps with timers must be either held by user space
* or pinned in bpffs.
*/
ret = -EPERM;
goto out;
}
/* allocate hrtimer via map_kmalloc to use memcg accounting */
t = bpf_map_kmalloc_node(map, sizeof(*t), GFP_ATOMIC, map->numa_node);
if (!t) {
ret = -ENOMEM;
goto out;
}
t->value = (void *)timer - map->timer_off;
t->map = map;
t->prog = NULL;
rcu_assign_pointer(t->callback_fn, NULL);
hrtimer_init(&t->timer, clockid, HRTIMER_MODE_REL_SOFT);
t->timer.function = bpf_timer_cb;
timer->timer = t;
out:
__bpf_spin_unlock_irqrestore(&timer->lock);
return ret;
}
static const struct bpf_func_proto bpf_timer_init_proto = {
.func = bpf_timer_init,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_TIMER,
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_ANYTHING,
};
BPF_CALL_3(bpf_timer_set_callback, struct bpf_timer_kern *, timer, void *, callback_fn,
struct bpf_prog_aux *, aux)
{
struct bpf_prog *prev, *prog = aux->prog;
struct bpf_hrtimer *t;
int ret = 0;
if (in_nmi())
return -EOPNOTSUPP;
__bpf_spin_lock_irqsave(&timer->lock);
t = timer->timer;
if (!t) {
ret = -EINVAL;
goto out;
}
if (!atomic64_read(&t->map->usercnt)) {
/* maps with timers must be either held by user space
* or pinned in bpffs. Otherwise timer might still be
* running even when bpf prog is detached and user space
* is gone, since map_release_uref won't ever be called.
*/
ret = -EPERM;
goto out;
}
prev = t->prog;
if (prev != prog) {
/* Bump prog refcnt once. Every bpf_timer_set_callback()
* can pick different callback_fn-s within the same prog.
*/
prog = bpf_prog_inc_not_zero(prog);
if (IS_ERR(prog)) {
ret = PTR_ERR(prog);
goto out;
}
if (prev)
/* Drop prev prog refcnt when swapping with new prog */
bpf_prog_put(prev);
t->prog = prog;
}
rcu_assign_pointer(t->callback_fn, callback_fn);
out:
__bpf_spin_unlock_irqrestore(&timer->lock);
return ret;
}
static const struct bpf_func_proto bpf_timer_set_callback_proto = {
.func = bpf_timer_set_callback,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_TIMER,
.arg2_type = ARG_PTR_TO_FUNC,
};
BPF_CALL_3(bpf_timer_start, struct bpf_timer_kern *, timer, u64, nsecs, u64, flags)
{
struct bpf_hrtimer *t;
int ret = 0;
if (in_nmi())
return -EOPNOTSUPP;
if (flags)
return -EINVAL;
__bpf_spin_lock_irqsave(&timer->lock);
t = timer->timer;
if (!t || !t->prog) {
ret = -EINVAL;
goto out;
}
hrtimer_start(&t->timer, ns_to_ktime(nsecs), HRTIMER_MODE_REL_SOFT);
out:
__bpf_spin_unlock_irqrestore(&timer->lock);
return ret;
}
static const struct bpf_func_proto bpf_timer_start_proto = {
.func = bpf_timer_start,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_TIMER,
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_ANYTHING,
};
static void drop_prog_refcnt(struct bpf_hrtimer *t)
{
struct bpf_prog *prog = t->prog;
if (prog) {
bpf_prog_put(prog);
t->prog = NULL;
rcu_assign_pointer(t->callback_fn, NULL);
}
}
BPF_CALL_1(bpf_timer_cancel, struct bpf_timer_kern *, timer)
{
struct bpf_hrtimer *t;
int ret = 0;
if (in_nmi())
return -EOPNOTSUPP;
__bpf_spin_lock_irqsave(&timer->lock);
t = timer->timer;
if (!t) {
ret = -EINVAL;
goto out;
}
if (this_cpu_read(hrtimer_running) == t) {
/* If bpf callback_fn is trying to bpf_timer_cancel()
* its own timer the hrtimer_cancel() will deadlock
* since it waits for callback_fn to finish
*/
ret = -EDEADLK;
goto out;
}
drop_prog_refcnt(t);
out:
__bpf_spin_unlock_irqrestore(&timer->lock);
/* Cancel the timer and wait for associated callback to finish
* if it was running.
*/
ret = ret ?: hrtimer_cancel(&t->timer);
return ret;
}
static const struct bpf_func_proto bpf_timer_cancel_proto = {
.func = bpf_timer_cancel,
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_TIMER,
};
/* This function is called by map_delete/update_elem for individual element and
* by ops->map_release_uref when the user space reference to a map reaches zero.
*/
void bpf_timer_cancel_and_free(void *val)
{
struct bpf_timer_kern *timer = val;
struct bpf_hrtimer *t;
/* Performance optimization: read timer->timer without lock first. */
if (!READ_ONCE(timer->timer))
return;
__bpf_spin_lock_irqsave(&timer->lock);
/* re-read it under lock */
t = timer->timer;
if (!t)
goto out;
drop_prog_refcnt(t);
/* The subsequent bpf_timer_start/cancel() helpers won't be able to use
* this timer, since it won't be initialized.
*/
timer->timer = NULL;
out:
__bpf_spin_unlock_irqrestore(&timer->lock);
if (!t)
return;
/* Cancel the timer and wait for callback to complete if it was running.
* If hrtimer_cancel() can be safely called it's safe to call kfree(t)
* right after for both preallocated and non-preallocated maps.
* The timer->timer = NULL was already done and no code path can
* see address 't' anymore.
*
* Check that bpf_map_delete/update_elem() wasn't called from timer
* callback_fn. In such case don't call hrtimer_cancel() (since it will
* deadlock) and don't call hrtimer_try_to_cancel() (since it will just
* return -1). Though callback_fn is still running on this cpu it's
* safe to do kfree(t) because bpf_timer_cb() read everything it needed
* from 't'. The bpf subprog callback_fn won't be able to access 't',
* since timer->timer = NULL was already done. The timer will be
* effectively cancelled because bpf_timer_cb() will return
* HRTIMER_NORESTART.
*/
if (this_cpu_read(hrtimer_running) != t)
hrtimer_cancel(&t->timer);
kfree(t);
}
const struct bpf_func_proto bpf_get_current_task_proto __weak;
const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
const struct bpf_func_proto bpf_probe_read_user_proto __weak;
const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
const struct bpf_func_proto bpf_probe_read_kernel_proto __weak;
const struct bpf_func_proto bpf_probe_read_kernel_str_proto __weak;
const struct bpf_func_proto bpf_task_pt_regs_proto __weak;
const struct bpf_func_proto *
bpf_base_func_proto(enum bpf_func_id func_id)
{
switch (func_id) {
case BPF_FUNC_map_lookup_elem:
return &bpf_map_lookup_elem_proto;
case BPF_FUNC_map_update_elem:
return &bpf_map_update_elem_proto;
case BPF_FUNC_map_delete_elem:
return &bpf_map_delete_elem_proto;
case BPF_FUNC_map_push_elem:
return &bpf_map_push_elem_proto;
case BPF_FUNC_map_pop_elem:
return &bpf_map_pop_elem_proto;
case BPF_FUNC_map_peek_elem:
return &bpf_map_peek_elem_proto;
case BPF_FUNC_get_prandom_u32:
return &bpf_get_prandom_u32_proto;
case BPF_FUNC_get_smp_processor_id:
return &bpf_get_raw_smp_processor_id_proto;
case BPF_FUNC_get_numa_node_id:
return &bpf_get_numa_node_id_proto;
case BPF_FUNC_tail_call:
return &bpf_tail_call_proto;
case BPF_FUNC_ktime_get_ns:
return &bpf_ktime_get_ns_proto;
case BPF_FUNC_ktime_get_boot_ns:
return &bpf_ktime_get_boot_ns_proto;
case BPF_FUNC_ringbuf_output:
return &bpf_ringbuf_output_proto;
case BPF_FUNC_ringbuf_reserve:
return &bpf_ringbuf_reserve_proto;
case BPF_FUNC_ringbuf_submit:
return &bpf_ringbuf_submit_proto;
case BPF_FUNC_ringbuf_discard:
return &bpf_ringbuf_discard_proto;
case BPF_FUNC_ringbuf_query:
return &bpf_ringbuf_query_proto;
case BPF_FUNC_for_each_map_elem:
return &bpf_for_each_map_elem_proto;
case BPF_FUNC_loop:
return &bpf_loop_proto;
case BPF_FUNC_strncmp:
return &bpf_strncmp_proto;
default:
break;
}
if (!bpf_capable())
return NULL;
switch (func_id) {
case BPF_FUNC_spin_lock:
return &bpf_spin_lock_proto;
case BPF_FUNC_spin_unlock:
return &bpf_spin_unlock_proto;
case BPF_FUNC_jiffies64:
return &bpf_jiffies64_proto;
case BPF_FUNC_per_cpu_ptr:
return &bpf_per_cpu_ptr_proto;
case BPF_FUNC_this_cpu_ptr:
return &bpf_this_cpu_ptr_proto;
case BPF_FUNC_timer_init:
return &bpf_timer_init_proto;
case BPF_FUNC_timer_set_callback:
return &bpf_timer_set_callback_proto;
case BPF_FUNC_timer_start:
return &bpf_timer_start_proto;
case BPF_FUNC_timer_cancel:
return &bpf_timer_cancel_proto;
default:
break;
}
if (!perfmon_capable())
return NULL;
switch (func_id) {
case BPF_FUNC_trace_printk:
return bpf_get_trace_printk_proto();
case BPF_FUNC_get_current_task:
return &bpf_get_current_task_proto;
case BPF_FUNC_get_current_task_btf:
return &bpf_get_current_task_btf_proto;
case BPF_FUNC_probe_read_user:
return &bpf_probe_read_user_proto;
case BPF_FUNC_probe_read_kernel:
return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
NULL : &bpf_probe_read_kernel_proto;
case BPF_FUNC_probe_read_user_str:
return &bpf_probe_read_user_str_proto;
case BPF_FUNC_probe_read_kernel_str:
return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
NULL : &bpf_probe_read_kernel_str_proto;
case BPF_FUNC_snprintf_btf:
return &bpf_snprintf_btf_proto;
case BPF_FUNC_snprintf:
return &bpf_snprintf_proto;
case BPF_FUNC_task_pt_regs:
return &bpf_task_pt_regs_proto;
case BPF_FUNC_trace_vprintk:
return bpf_get_trace_vprintk_proto();
default:
return NULL;
}
}