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/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/bpf.h>
#include <linux/rcupdate.h>
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/ktime.h>
#include <linux/sched.h>
#include <linux/uidgid.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.
*/
static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
/* verifier checked that R1 contains a valid pointer to bpf_map
* and R2 points to a program stack and map->key_size bytes were
* initialized
*/
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
void *key = (void *) (unsigned long) r2;
void *value;
WARN_ON_ONCE(!rcu_read_lock_held());
value = map->ops->map_lookup_elem(map, key);
/* lookup() returns either pointer to element value or NULL
* which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type
*/
return (unsigned long) value;
}
const struct bpf_func_proto bpf_map_lookup_elem_proto = {
.func = bpf_map_lookup_elem,
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_MAP_KEY,
};
static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
void *key = (void *) (unsigned long) r2;
void *value = (void *) (unsigned long) r3;
WARN_ON_ONCE(!rcu_read_lock_held());
return map->ops->map_update_elem(map, key, value, r4);
}
const struct bpf_func_proto bpf_map_update_elem_proto = {
.func = bpf_map_update_elem,
.gpl_only = false,
.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,
};
static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
void *key = (void *) (unsigned long) r2;
WARN_ON_ONCE(!rcu_read_lock_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,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_MAP_KEY,
};
const struct bpf_func_proto bpf_get_prandom_u32_proto = {
.func = bpf_user_rnd_u32,
.gpl_only = false,
.ret_type = RET_INTEGER,
};
static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
return raw_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,
};
static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
/* 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 = true,
.ret_type = RET_INTEGER,
};
static u64 bpf_get_current_pid_tgid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct task_struct *task = current;
if (!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,
};
static u64 bpf_get_current_uid_gid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct task_struct *task = current;
kuid_t uid;
kgid_t gid;
if (!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,
};
static u64 bpf_get_current_comm(u64 r1, u64 size, u64 r3, u64 r4, u64 r5)
{
struct task_struct *task = current;
char *buf = (char *) (long) r1;
if (unlikely(!task))
goto err_clear;
strncpy(buf, task->comm, size);
/* Verifier guarantees that size > 0. For task->comm exceeding
* size, guarantee that buf is %NUL-terminated. Unconditionally
* done here to save the size test.
*/
buf[size - 1] = 0;
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_RAW_STACK,
.arg2_type = ARG_CONST_STACK_SIZE,
};
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