1 // SPDX-License-Identifier: GPL-2.0 2 // bpf-lirc.c - handles bpf 3 // 4 // Copyright (C) 2018 Sean Young <sean@mess.org> 5 6 #include <linux/bpf.h> 7 #include <linux/filter.h> 8 #include <linux/bpf_lirc.h> 9 #include "rc-core-priv.h" 10 11 /* 12 * BPF interface for raw IR 13 */ 14 const struct bpf_prog_ops lirc_mode2_prog_ops = { 15 }; 16 17 BPF_CALL_1(bpf_rc_repeat, u32*, sample) 18 { 19 struct ir_raw_event_ctrl *ctrl; 20 21 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); 22 23 rc_repeat(ctrl->dev); 24 25 return 0; 26 } 27 28 static const struct bpf_func_proto rc_repeat_proto = { 29 .func = bpf_rc_repeat, 30 .gpl_only = true, /* rc_repeat is EXPORT_SYMBOL_GPL */ 31 .ret_type = RET_INTEGER, 32 .arg1_type = ARG_PTR_TO_CTX, 33 }; 34 35 /* 36 * Currently rc-core does not support 64-bit scancodes, but there are many 37 * known protocols with more than 32 bits. So, define the interface as u64 38 * as a future-proof. 39 */ 40 BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode, 41 u32, toggle) 42 { 43 struct ir_raw_event_ctrl *ctrl; 44 45 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); 46 47 rc_keydown(ctrl->dev, protocol, scancode, toggle != 0); 48 49 return 0; 50 } 51 52 static const struct bpf_func_proto rc_keydown_proto = { 53 .func = bpf_rc_keydown, 54 .gpl_only = true, /* rc_keydown is EXPORT_SYMBOL_GPL */ 55 .ret_type = RET_INTEGER, 56 .arg1_type = ARG_PTR_TO_CTX, 57 .arg2_type = ARG_ANYTHING, 58 .arg3_type = ARG_ANYTHING, 59 .arg4_type = ARG_ANYTHING, 60 }; 61 62 BPF_CALL_3(bpf_rc_pointer_rel, u32*, sample, s32, rel_x, s32, rel_y) 63 { 64 struct ir_raw_event_ctrl *ctrl; 65 66 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); 67 68 input_report_rel(ctrl->dev->input_dev, REL_X, rel_x); 69 input_report_rel(ctrl->dev->input_dev, REL_Y, rel_y); 70 input_sync(ctrl->dev->input_dev); 71 72 return 0; 73 } 74 75 static const struct bpf_func_proto rc_pointer_rel_proto = { 76 .func = bpf_rc_pointer_rel, 77 .gpl_only = true, 78 .ret_type = RET_INTEGER, 79 .arg1_type = ARG_PTR_TO_CTX, 80 .arg2_type = ARG_ANYTHING, 81 .arg3_type = ARG_ANYTHING, 82 }; 83 84 static const struct bpf_func_proto * 85 lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 86 { 87 switch (func_id) { 88 case BPF_FUNC_rc_repeat: 89 return &rc_repeat_proto; 90 case BPF_FUNC_rc_keydown: 91 return &rc_keydown_proto; 92 case BPF_FUNC_rc_pointer_rel: 93 return &rc_pointer_rel_proto; 94 case BPF_FUNC_map_lookup_elem: 95 return &bpf_map_lookup_elem_proto; 96 case BPF_FUNC_map_update_elem: 97 return &bpf_map_update_elem_proto; 98 case BPF_FUNC_map_delete_elem: 99 return &bpf_map_delete_elem_proto; 100 case BPF_FUNC_map_push_elem: 101 return &bpf_map_push_elem_proto; 102 case BPF_FUNC_map_pop_elem: 103 return &bpf_map_pop_elem_proto; 104 case BPF_FUNC_map_peek_elem: 105 return &bpf_map_peek_elem_proto; 106 case BPF_FUNC_ktime_get_ns: 107 return &bpf_ktime_get_ns_proto; 108 case BPF_FUNC_tail_call: 109 return &bpf_tail_call_proto; 110 case BPF_FUNC_get_prandom_u32: 111 return &bpf_get_prandom_u32_proto; 112 case BPF_FUNC_trace_printk: 113 if (capable(CAP_SYS_ADMIN)) 114 return bpf_get_trace_printk_proto(); 115 /* fall through */ 116 default: 117 return NULL; 118 } 119 } 120 121 static bool lirc_mode2_is_valid_access(int off, int size, 122 enum bpf_access_type type, 123 const struct bpf_prog *prog, 124 struct bpf_insn_access_aux *info) 125 { 126 /* We have one field of u32 */ 127 return type == BPF_READ && off == 0 && size == sizeof(u32); 128 } 129 130 const struct bpf_verifier_ops lirc_mode2_verifier_ops = { 131 .get_func_proto = lirc_mode2_func_proto, 132 .is_valid_access = lirc_mode2_is_valid_access 133 }; 134 135 #define BPF_MAX_PROGS 64 136 137 static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) 138 { 139 struct bpf_prog_array __rcu *old_array; 140 struct bpf_prog_array *new_array; 141 struct ir_raw_event_ctrl *raw; 142 int ret; 143 144 if (rcdev->driver_type != RC_DRIVER_IR_RAW) 145 return -EINVAL; 146 147 ret = mutex_lock_interruptible(&ir_raw_handler_lock); 148 if (ret) 149 return ret; 150 151 raw = rcdev->raw; 152 if (!raw) { 153 ret = -ENODEV; 154 goto unlock; 155 } 156 157 if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) { 158 ret = -E2BIG; 159 goto unlock; 160 } 161 162 old_array = raw->progs; 163 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); 164 if (ret < 0) 165 goto unlock; 166 167 rcu_assign_pointer(raw->progs, new_array); 168 bpf_prog_array_free(old_array); 169 170 unlock: 171 mutex_unlock(&ir_raw_handler_lock); 172 return ret; 173 } 174 175 static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) 176 { 177 struct bpf_prog_array __rcu *old_array; 178 struct bpf_prog_array *new_array; 179 struct ir_raw_event_ctrl *raw; 180 int ret; 181 182 if (rcdev->driver_type != RC_DRIVER_IR_RAW) 183 return -EINVAL; 184 185 ret = mutex_lock_interruptible(&ir_raw_handler_lock); 186 if (ret) 187 return ret; 188 189 raw = rcdev->raw; 190 if (!raw) { 191 ret = -ENODEV; 192 goto unlock; 193 } 194 195 old_array = raw->progs; 196 ret = bpf_prog_array_copy(old_array, prog, NULL, &new_array); 197 /* 198 * Do not use bpf_prog_array_delete_safe() as we would end up 199 * with a dummy entry in the array, and the we would free the 200 * dummy in lirc_bpf_free() 201 */ 202 if (ret) 203 goto unlock; 204 205 rcu_assign_pointer(raw->progs, new_array); 206 bpf_prog_array_free(old_array); 207 bpf_prog_put(prog); 208 unlock: 209 mutex_unlock(&ir_raw_handler_lock); 210 return ret; 211 } 212 213 void lirc_bpf_run(struct rc_dev *rcdev, u32 sample) 214 { 215 struct ir_raw_event_ctrl *raw = rcdev->raw; 216 217 raw->bpf_sample = sample; 218 219 if (raw->progs) 220 BPF_PROG_RUN_ARRAY(raw->progs, &raw->bpf_sample, BPF_PROG_RUN); 221 } 222 223 /* 224 * This should be called once the rc thread has been stopped, so there can be 225 * no concurrent bpf execution. 226 */ 227 void lirc_bpf_free(struct rc_dev *rcdev) 228 { 229 struct bpf_prog_array_item *item; 230 231 if (!rcdev->raw->progs) 232 return; 233 234 item = rcu_dereference(rcdev->raw->progs)->items; 235 while (item->prog) { 236 bpf_prog_put(item->prog); 237 item++; 238 } 239 240 bpf_prog_array_free(rcdev->raw->progs); 241 } 242 243 int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) 244 { 245 struct rc_dev *rcdev; 246 int ret; 247 248 if (attr->attach_flags) 249 return -EINVAL; 250 251 rcdev = rc_dev_get_from_fd(attr->target_fd); 252 if (IS_ERR(rcdev)) 253 return PTR_ERR(rcdev); 254 255 ret = lirc_bpf_attach(rcdev, prog); 256 257 put_device(&rcdev->dev); 258 259 return ret; 260 } 261 262 int lirc_prog_detach(const union bpf_attr *attr) 263 { 264 struct bpf_prog *prog; 265 struct rc_dev *rcdev; 266 int ret; 267 268 if (attr->attach_flags) 269 return -EINVAL; 270 271 prog = bpf_prog_get_type(attr->attach_bpf_fd, 272 BPF_PROG_TYPE_LIRC_MODE2); 273 if (IS_ERR(prog)) 274 return PTR_ERR(prog); 275 276 rcdev = rc_dev_get_from_fd(attr->target_fd); 277 if (IS_ERR(rcdev)) { 278 bpf_prog_put(prog); 279 return PTR_ERR(rcdev); 280 } 281 282 ret = lirc_bpf_detach(rcdev, prog); 283 284 bpf_prog_put(prog); 285 put_device(&rcdev->dev); 286 287 return ret; 288 } 289 290 int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) 291 { 292 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); 293 struct bpf_prog_array __rcu *progs; 294 struct rc_dev *rcdev; 295 u32 cnt, flags = 0; 296 int ret; 297 298 if (attr->query.query_flags) 299 return -EINVAL; 300 301 rcdev = rc_dev_get_from_fd(attr->query.target_fd); 302 if (IS_ERR(rcdev)) 303 return PTR_ERR(rcdev); 304 305 if (rcdev->driver_type != RC_DRIVER_IR_RAW) { 306 ret = -EINVAL; 307 goto put; 308 } 309 310 ret = mutex_lock_interruptible(&ir_raw_handler_lock); 311 if (ret) 312 goto put; 313 314 progs = rcdev->raw->progs; 315 cnt = progs ? bpf_prog_array_length(progs) : 0; 316 317 if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) { 318 ret = -EFAULT; 319 goto unlock; 320 } 321 322 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) { 323 ret = -EFAULT; 324 goto unlock; 325 } 326 327 if (attr->query.prog_cnt != 0 && prog_ids && cnt) 328 ret = bpf_prog_array_copy_to_user(progs, prog_ids, cnt); 329 330 unlock: 331 mutex_unlock(&ir_raw_handler_lock); 332 put: 333 put_device(&rcdev->dev); 334 335 return ret; 336 } 337