1/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  2 *
  3 * This program is free software; you can redistribute it and/or
  4 * modify it under the terms of version 2 of the GNU General Public
  5 * License as published by the Free Software Foundation.
  6 *
  7 * This program is distributed in the hope that it will be useful, but
  8 * WITHOUT ANY WARRANTY; without even the implied warranty of
  9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 10 * General Public License for more details.
 11 */
 12#include <linux/bpf.h>
 13#include <linux/rcupdate.h>
 14#include <linux/random.h>
 15#include <linux/smp.h>
 16#include <linux/topology.h>
 17#include <linux/ktime.h>
 18#include <linux/sched.h>
 19#include <linux/uidgid.h>
 20#include <linux/filter.h>
 21
 22/* If kernel subsystem is allowing eBPF programs to call this function,
 23 * inside its own verifier_ops->get_func_proto() callback it should return
 24 * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
 25 *
 26 * Different map implementations will rely on rcu in map methods
 27 * lookup/update/delete, therefore eBPF programs must run under rcu lock
 28 * if program is allowed to access maps, so check rcu_read_lock_held in
 29 * all three functions.
 30 */
 31BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
 32{
 33	WARN_ON_ONCE(!rcu_read_lock_held());
 34	return (unsigned long) map->ops->map_lookup_elem(map, key);
 35}
 36
 37const struct bpf_func_proto bpf_map_lookup_elem_proto = {
 38	.func		= bpf_map_lookup_elem,
 39	.gpl_only	= false,
 40	.pkt_access	= true,
 41	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
 42	.arg1_type	= ARG_CONST_MAP_PTR,
 43	.arg2_type	= ARG_PTR_TO_MAP_KEY,
 44};
 45
 46BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
 47	   void *, value, u64, flags)
 48{
 49	WARN_ON_ONCE(!rcu_read_lock_held());
 50	return map->ops->map_update_elem(map, key, value, flags);
 51}
 52
 53const struct bpf_func_proto bpf_map_update_elem_proto = {
 54	.func		= bpf_map_update_elem,
 55	.gpl_only	= false,
 56	.pkt_access	= true,
 57	.ret_type	= RET_INTEGER,
 58	.arg1_type	= ARG_CONST_MAP_PTR,
 59	.arg2_type	= ARG_PTR_TO_MAP_KEY,
 60	.arg3_type	= ARG_PTR_TO_MAP_VALUE,
 61	.arg4_type	= ARG_ANYTHING,
 62};
 63
 64BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
 65{
 66	WARN_ON_ONCE(!rcu_read_lock_held());
 67	return map->ops->map_delete_elem(map, key);
 68}
 69
 70const struct bpf_func_proto bpf_map_delete_elem_proto = {
 71	.func		= bpf_map_delete_elem,
 72	.gpl_only	= false,
 73	.pkt_access	= true,
 74	.ret_type	= RET_INTEGER,
 75	.arg1_type	= ARG_CONST_MAP_PTR,
 76	.arg2_type	= ARG_PTR_TO_MAP_KEY,
 77};
 78
 79const struct bpf_func_proto bpf_get_prandom_u32_proto = {
 80	.func		= bpf_user_rnd_u32,
 81	.gpl_only	= false,
 82	.ret_type	= RET_INTEGER,
 83};
 84
 85BPF_CALL_0(bpf_get_smp_processor_id)
 86{
 87	return smp_processor_id();
 88}
 89
 90const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
 91	.func		= bpf_get_smp_processor_id,
 92	.gpl_only	= false,
 93	.ret_type	= RET_INTEGER,
 94};
 95
 96BPF_CALL_0(bpf_get_numa_node_id)
 97{
 98	return numa_node_id();
 99}
100
101const struct bpf_func_proto bpf_get_numa_node_id_proto = {
102	.func		= bpf_get_numa_node_id,
103	.gpl_only	= false,
104	.ret_type	= RET_INTEGER,
105};
106
107BPF_CALL_0(bpf_ktime_get_ns)
108{
109	/* NMI safe access to clock monotonic */
110	return ktime_get_mono_fast_ns();
111}
112
113const struct bpf_func_proto bpf_ktime_get_ns_proto = {
114	.func		= bpf_ktime_get_ns,
115	.gpl_only	= true,
116	.ret_type	= RET_INTEGER,
117};
118
119BPF_CALL_0(bpf_get_current_pid_tgid)
120{
121	struct task_struct *task = current;
122
123	if (unlikely(!task))
124		return -EINVAL;
125
126	return (u64) task->tgid << 32 | task->pid;
127}
128
129const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
130	.func		= bpf_get_current_pid_tgid,
131	.gpl_only	= false,
132	.ret_type	= RET_INTEGER,
133};
134
135BPF_CALL_0(bpf_get_current_uid_gid)
136{
137	struct task_struct *task = current;
138	kuid_t uid;
139	kgid_t gid;
140
141	if (unlikely(!task))
142		return -EINVAL;
143
144	current_uid_gid(&uid, &gid);
145	return (u64) from_kgid(&init_user_ns, gid) << 32 |
146		     from_kuid(&init_user_ns, uid);
147}
148
149const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
150	.func		= bpf_get_current_uid_gid,
151	.gpl_only	= false,
152	.ret_type	= RET_INTEGER,
153};
154
155BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
156{
157	struct task_struct *task = current;
158
159	if (unlikely(!task))
160		goto err_clear;
161
162	strncpy(buf, task->comm, size);
163
164	/* Verifier guarantees that size > 0. For task->comm exceeding
165	 * size, guarantee that buf is %NUL-terminated. Unconditionally
166	 * done here to save the size test.
167	 */
168	buf[size - 1] = 0;
169	return 0;
170err_clear:
171	memset(buf, 0, size);
172	return -EINVAL;
173}
174
175const struct bpf_func_proto bpf_get_current_comm_proto = {
176	.func		= bpf_get_current_comm,
177	.gpl_only	= false,
178	.ret_type	= RET_INTEGER,
179	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
180	.arg2_type	= ARG_CONST_SIZE,
181};