Alexei Starovoitov | d0003ec | 2014-11-13 17:36:49 -0800 | [diff] [blame] | 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> |
Daniel Borkmann | 03e69b5 | 2015-03-14 02:27:16 +0100 | [diff] [blame] | 14 | #include <linux/random.h> |
Daniel Borkmann | c04167c | 2015-03-14 02:27:17 +0100 | [diff] [blame] | 15 | #include <linux/smp.h> |
Daniel Borkmann | 17ca8cb | 2015-05-29 23:23:06 +0200 | [diff] [blame] | 16 | #include <linux/ktime.h> |
Alexei Starovoitov | ffeedaf | 2015-06-12 19:39:12 -0700 | [diff] [blame] | 17 | #include <linux/sched.h> |
| 18 | #include <linux/uidgid.h> |
Alexei Starovoitov | d0003ec | 2014-11-13 17:36:49 -0800 | [diff] [blame] | 19 | |
| 20 | /* If kernel subsystem is allowing eBPF programs to call this function, |
| 21 | * inside its own verifier_ops->get_func_proto() callback it should return |
| 22 | * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments |
| 23 | * |
| 24 | * Different map implementations will rely on rcu in map methods |
| 25 | * lookup/update/delete, therefore eBPF programs must run under rcu lock |
| 26 | * if program is allowed to access maps, so check rcu_read_lock_held in |
| 27 | * all three functions. |
| 28 | */ |
| 29 | static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| 30 | { |
| 31 | /* verifier checked that R1 contains a valid pointer to bpf_map |
| 32 | * and R2 points to a program stack and map->key_size bytes were |
| 33 | * initialized |
| 34 | */ |
| 35 | struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; |
| 36 | void *key = (void *) (unsigned long) r2; |
| 37 | void *value; |
| 38 | |
| 39 | WARN_ON_ONCE(!rcu_read_lock_held()); |
| 40 | |
| 41 | value = map->ops->map_lookup_elem(map, key); |
| 42 | |
| 43 | /* lookup() returns either pointer to element value or NULL |
| 44 | * which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type |
| 45 | */ |
| 46 | return (unsigned long) value; |
| 47 | } |
| 48 | |
Daniel Borkmann | a2c83ff | 2015-03-01 12:31:42 +0100 | [diff] [blame] | 49 | const struct bpf_func_proto bpf_map_lookup_elem_proto = { |
Daniel Borkmann | 3324b58 | 2015-05-29 23:23:07 +0200 | [diff] [blame] | 50 | .func = bpf_map_lookup_elem, |
| 51 | .gpl_only = false, |
| 52 | .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, |
| 53 | .arg1_type = ARG_CONST_MAP_PTR, |
| 54 | .arg2_type = ARG_PTR_TO_MAP_KEY, |
Alexei Starovoitov | d0003ec | 2014-11-13 17:36:49 -0800 | [diff] [blame] | 55 | }; |
| 56 | |
| 57 | static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| 58 | { |
| 59 | struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; |
| 60 | void *key = (void *) (unsigned long) r2; |
| 61 | void *value = (void *) (unsigned long) r3; |
| 62 | |
| 63 | WARN_ON_ONCE(!rcu_read_lock_held()); |
| 64 | |
| 65 | return map->ops->map_update_elem(map, key, value, r4); |
| 66 | } |
| 67 | |
Daniel Borkmann | a2c83ff | 2015-03-01 12:31:42 +0100 | [diff] [blame] | 68 | const struct bpf_func_proto bpf_map_update_elem_proto = { |
Daniel Borkmann | 3324b58 | 2015-05-29 23:23:07 +0200 | [diff] [blame] | 69 | .func = bpf_map_update_elem, |
| 70 | .gpl_only = false, |
| 71 | .ret_type = RET_INTEGER, |
| 72 | .arg1_type = ARG_CONST_MAP_PTR, |
| 73 | .arg2_type = ARG_PTR_TO_MAP_KEY, |
| 74 | .arg3_type = ARG_PTR_TO_MAP_VALUE, |
| 75 | .arg4_type = ARG_ANYTHING, |
Alexei Starovoitov | d0003ec | 2014-11-13 17:36:49 -0800 | [diff] [blame] | 76 | }; |
| 77 | |
| 78 | static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| 79 | { |
| 80 | struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; |
| 81 | void *key = (void *) (unsigned long) r2; |
| 82 | |
| 83 | WARN_ON_ONCE(!rcu_read_lock_held()); |
| 84 | |
| 85 | return map->ops->map_delete_elem(map, key); |
| 86 | } |
| 87 | |
Daniel Borkmann | a2c83ff | 2015-03-01 12:31:42 +0100 | [diff] [blame] | 88 | const struct bpf_func_proto bpf_map_delete_elem_proto = { |
Daniel Borkmann | 3324b58 | 2015-05-29 23:23:07 +0200 | [diff] [blame] | 89 | .func = bpf_map_delete_elem, |
| 90 | .gpl_only = false, |
| 91 | .ret_type = RET_INTEGER, |
| 92 | .arg1_type = ARG_CONST_MAP_PTR, |
| 93 | .arg2_type = ARG_PTR_TO_MAP_KEY, |
Alexei Starovoitov | d0003ec | 2014-11-13 17:36:49 -0800 | [diff] [blame] | 94 | }; |
Daniel Borkmann | 03e69b5 | 2015-03-14 02:27:16 +0100 | [diff] [blame] | 95 | |
Daniel Borkmann | 03e69b5 | 2015-03-14 02:27:16 +0100 | [diff] [blame] | 96 | const struct bpf_func_proto bpf_get_prandom_u32_proto = { |
Daniel Borkmann | 3ad0040 | 2015-10-08 01:20:39 +0200 | [diff] [blame] | 97 | .func = bpf_user_rnd_u32, |
Daniel Borkmann | 03e69b5 | 2015-03-14 02:27:16 +0100 | [diff] [blame] | 98 | .gpl_only = false, |
| 99 | .ret_type = RET_INTEGER, |
| 100 | }; |
Daniel Borkmann | c04167c | 2015-03-14 02:27:17 +0100 | [diff] [blame] | 101 | |
| 102 | static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| 103 | { |
| 104 | return raw_smp_processor_id(); |
| 105 | } |
| 106 | |
| 107 | const struct bpf_func_proto bpf_get_smp_processor_id_proto = { |
| 108 | .func = bpf_get_smp_processor_id, |
| 109 | .gpl_only = false, |
| 110 | .ret_type = RET_INTEGER, |
| 111 | }; |
Daniel Borkmann | 17ca8cb | 2015-05-29 23:23:06 +0200 | [diff] [blame] | 112 | |
| 113 | static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| 114 | { |
| 115 | /* NMI safe access to clock monotonic */ |
| 116 | return ktime_get_mono_fast_ns(); |
| 117 | } |
| 118 | |
| 119 | const struct bpf_func_proto bpf_ktime_get_ns_proto = { |
| 120 | .func = bpf_ktime_get_ns, |
| 121 | .gpl_only = true, |
| 122 | .ret_type = RET_INTEGER, |
| 123 | }; |
Alexei Starovoitov | ffeedaf | 2015-06-12 19:39:12 -0700 | [diff] [blame] | 124 | |
| 125 | static u64 bpf_get_current_pid_tgid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| 126 | { |
| 127 | struct task_struct *task = current; |
| 128 | |
| 129 | if (!task) |
| 130 | return -EINVAL; |
| 131 | |
| 132 | return (u64) task->tgid << 32 | task->pid; |
| 133 | } |
| 134 | |
| 135 | const struct bpf_func_proto bpf_get_current_pid_tgid_proto = { |
| 136 | .func = bpf_get_current_pid_tgid, |
| 137 | .gpl_only = false, |
| 138 | .ret_type = RET_INTEGER, |
| 139 | }; |
| 140 | |
| 141 | static u64 bpf_get_current_uid_gid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) |
| 142 | { |
| 143 | struct task_struct *task = current; |
| 144 | kuid_t uid; |
| 145 | kgid_t gid; |
| 146 | |
| 147 | if (!task) |
| 148 | return -EINVAL; |
| 149 | |
| 150 | current_uid_gid(&uid, &gid); |
| 151 | return (u64) from_kgid(&init_user_ns, gid) << 32 | |
| 152 | from_kuid(&init_user_ns, uid); |
| 153 | } |
| 154 | |
| 155 | const struct bpf_func_proto bpf_get_current_uid_gid_proto = { |
| 156 | .func = bpf_get_current_uid_gid, |
| 157 | .gpl_only = false, |
| 158 | .ret_type = RET_INTEGER, |
| 159 | }; |
| 160 | |
| 161 | static u64 bpf_get_current_comm(u64 r1, u64 size, u64 r3, u64 r4, u64 r5) |
| 162 | { |
| 163 | struct task_struct *task = current; |
| 164 | char *buf = (char *) (long) r1; |
| 165 | |
Daniel Borkmann | 074f528 | 2016-04-13 00:10:52 +0200 | [diff] [blame] | 166 | if (unlikely(!task)) |
| 167 | goto err_clear; |
Alexei Starovoitov | ffeedaf | 2015-06-12 19:39:12 -0700 | [diff] [blame] | 168 | |
Daniel Borkmann | 074f528 | 2016-04-13 00:10:52 +0200 | [diff] [blame] | 169 | strncpy(buf, task->comm, size); |
| 170 | |
| 171 | /* Verifier guarantees that size > 0. For task->comm exceeding |
| 172 | * size, guarantee that buf is %NUL-terminated. Unconditionally |
| 173 | * done here to save the size test. |
| 174 | */ |
| 175 | buf[size - 1] = 0; |
Alexei Starovoitov | ffeedaf | 2015-06-12 19:39:12 -0700 | [diff] [blame] | 176 | return 0; |
Daniel Borkmann | 074f528 | 2016-04-13 00:10:52 +0200 | [diff] [blame] | 177 | err_clear: |
| 178 | memset(buf, 0, size); |
| 179 | return -EINVAL; |
Alexei Starovoitov | ffeedaf | 2015-06-12 19:39:12 -0700 | [diff] [blame] | 180 | } |
| 181 | |
| 182 | const struct bpf_func_proto bpf_get_current_comm_proto = { |
| 183 | .func = bpf_get_current_comm, |
| 184 | .gpl_only = false, |
| 185 | .ret_type = RET_INTEGER, |
Daniel Borkmann | 074f528 | 2016-04-13 00:10:52 +0200 | [diff] [blame] | 186 | .arg1_type = ARG_PTR_TO_RAW_STACK, |
Alexei Starovoitov | ffeedaf | 2015-06-12 19:39:12 -0700 | [diff] [blame] | 187 | .arg2_type = ARG_CONST_STACK_SIZE, |
| 188 | }; |