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_ktime_get_ns: 101 return &bpf_ktime_get_ns_proto; 102 case BPF_FUNC_tail_call: 103 return &bpf_tail_call_proto; 104 case BPF_FUNC_get_prandom_u32: 105 return &bpf_get_prandom_u32_proto; 106 case BPF_FUNC_trace_printk: 107 if (capable(CAP_SYS_ADMIN)) 108 return bpf_get_trace_printk_proto(); 109 /* fall through */ 110 default: 111 return NULL; 112 } 113 } 114 115 static bool lirc_mode2_is_valid_access(int off, int size, 116 enum bpf_access_type type, 117 const struct bpf_prog *prog, 118 struct bpf_insn_access_aux *info) 119 { 120 /* We have one field of u32 */ 121 return type == BPF_READ && off == 0 && size == sizeof(u32); 122 } 123 124 const struct bpf_verifier_ops lirc_mode2_verifier_ops = { 125 .get_func_proto = lirc_mode2_func_proto, 126 .is_valid_access = lirc_mode2_is_valid_access 127 }; 128 129 #define BPF_MAX_PROGS 64 130 131 static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) 132 { 133 struct bpf_prog_array __rcu *old_array; 134 struct bpf_prog_array *new_array; 135 struct ir_raw_event_ctrl *raw; 136 int ret; 137 138 if (rcdev->driver_type != RC_DRIVER_IR_RAW) 139 return -EINVAL; 140 141 ret = mutex_lock_interruptible(&ir_raw_handler_lock); 142 if (ret) 143 return ret; 144 145 raw = rcdev->raw; 146 if (!raw) { 147 ret = -ENODEV; 148 goto unlock; 149 } 150 151 if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) { 152 ret = -E2BIG; 153 goto unlock; 154 } 155 156 old_array = raw->progs; 157 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); 158 if (ret < 0) 159 goto unlock; 160 161 rcu_assign_pointer(raw->progs, new_array); 162 bpf_prog_array_free(old_array); 163 164 unlock: 165 mutex_unlock(&ir_raw_handler_lock); 166 return ret; 167 } 168 169 static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) 170 { 171 struct bpf_prog_array __rcu *old_array; 172 struct bpf_prog_array *new_array; 173 struct ir_raw_event_ctrl *raw; 174 int ret; 175 176 if (rcdev->driver_type != RC_DRIVER_IR_RAW) 177 return -EINVAL; 178 179 ret = mutex_lock_interruptible(&ir_raw_handler_lock); 180 if (ret) 181 return ret; 182 183 raw = rcdev->raw; 184 if (!raw) { 185 ret = -ENODEV; 186 goto unlock; 187 } 188 189 old_array = raw->progs; 190 ret = bpf_prog_array_copy(old_array, prog, NULL, &new_array); 191 /* 192 * Do not use bpf_prog_array_delete_safe() as we would end up 193 * with a dummy entry in the array, and the we would free the 194 * dummy in lirc_bpf_free() 195 */ 196 if (ret) 197 goto unlock; 198 199 rcu_assign_pointer(raw->progs, new_array); 200 bpf_prog_array_free(old_array); 201 bpf_prog_put(prog); 202 unlock: 203 mutex_unlock(&ir_raw_handler_lock); 204 return ret; 205 } 206 207 void lirc_bpf_run(struct rc_dev *rcdev, u32 sample) 208 { 209 struct ir_raw_event_ctrl *raw = rcdev->raw; 210 211 raw->bpf_sample = sample; 212 213 if (raw->progs) 214 BPF_PROG_RUN_ARRAY(raw->progs, &raw->bpf_sample, BPF_PROG_RUN); 215 } 216 217 /* 218 * This should be called once the rc thread has been stopped, so there can be 219 * no concurrent bpf execution. 220 */ 221 void lirc_bpf_free(struct rc_dev *rcdev) 222 { 223 struct bpf_prog_array_item *item; 224 225 if (!rcdev->raw->progs) 226 return; 227 228 item = rcu_dereference(rcdev->raw->progs)->items; 229 while (item->prog) { 230 bpf_prog_put(item->prog); 231 item++; 232 } 233 234 bpf_prog_array_free(rcdev->raw->progs); 235 } 236 237 int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) 238 { 239 struct rc_dev *rcdev; 240 int ret; 241 242 if (attr->attach_flags) 243 return -EINVAL; 244 245 rcdev = rc_dev_get_from_fd(attr->target_fd); 246 if (IS_ERR(rcdev)) 247 return PTR_ERR(rcdev); 248 249 ret = lirc_bpf_attach(rcdev, prog); 250 251 put_device(&rcdev->dev); 252 253 return ret; 254 } 255 256 int lirc_prog_detach(const union bpf_attr *attr) 257 { 258 struct bpf_prog *prog; 259 struct rc_dev *rcdev; 260 int ret; 261 262 if (attr->attach_flags) 263 return -EINVAL; 264 265 prog = bpf_prog_get_type(attr->attach_bpf_fd, 266 BPF_PROG_TYPE_LIRC_MODE2); 267 if (IS_ERR(prog)) 268 return PTR_ERR(prog); 269 270 rcdev = rc_dev_get_from_fd(attr->target_fd); 271 if (IS_ERR(rcdev)) { 272 bpf_prog_put(prog); 273 return PTR_ERR(rcdev); 274 } 275 276 ret = lirc_bpf_detach(rcdev, prog); 277 278 bpf_prog_put(prog); 279 put_device(&rcdev->dev); 280 281 return ret; 282 } 283 284 int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) 285 { 286 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); 287 struct bpf_prog_array __rcu *progs; 288 struct rc_dev *rcdev; 289 u32 cnt, flags = 0; 290 int ret; 291 292 if (attr->query.query_flags) 293 return -EINVAL; 294 295 rcdev = rc_dev_get_from_fd(attr->query.target_fd); 296 if (IS_ERR(rcdev)) 297 return PTR_ERR(rcdev); 298 299 if (rcdev->driver_type != RC_DRIVER_IR_RAW) { 300 ret = -EINVAL; 301 goto put; 302 } 303 304 ret = mutex_lock_interruptible(&ir_raw_handler_lock); 305 if (ret) 306 goto put; 307 308 progs = rcdev->raw->progs; 309 cnt = progs ? bpf_prog_array_length(progs) : 0; 310 311 if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) { 312 ret = -EFAULT; 313 goto unlock; 314 } 315 316 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) { 317 ret = -EFAULT; 318 goto unlock; 319 } 320 321 if (attr->query.prog_cnt != 0 && prog_ids && cnt) 322 ret = bpf_prog_array_copy_to_user(progs, prog_ids, cnt); 323 324 unlock: 325 mutex_unlock(&ir_raw_handler_lock); 326 put: 327 put_device(&rcdev->dev); 328 329 return ret; 330 } 331