| 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 | */ |
| 31 | BPF_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 | |
| 37 | const 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 | |
| 46 | BPF_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 | |
| 53 | const 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 | |
| 64 | BPF_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 | |
| 70 | const 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 | |
| 79 | const 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 | |
| 85 | BPF_CALL_0(bpf_get_smp_processor_id) |
| 86 | { |
| 87 | return smp_processor_id(); |
| 88 | } |
| 89 | |
| 90 | const 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 | |
| 96 | BPF_CALL_0(bpf_get_numa_node_id) |
| 97 | { |
| 98 | return numa_node_id(); |
| 99 | } |
| 100 | |
| 101 | const 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 | |
| 107 | BPF_CALL_0(bpf_ktime_get_ns) |
| 108 | { |
| 109 | /* NMI safe access to clock monotonic */ |
| 110 | return ktime_get_mono_fast_ns(); |
| 111 | } |
| 112 | |
| 113 | const 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 | |
| 119 | BPF_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 | |
| 129 | const 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 | |
| 135 | BPF_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 | |
| 149 | const 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 | |
| 155 | BPF_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; |
| 170 | err_clear: |
| 171 | memset(buf, 0, size); |
| 172 | return -EINVAL; |
| 173 | } |
| 174 | |
| 175 | const 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 | }; |