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 #define lirc_rcu_dereference(p) \ 12 rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock)) 13 14 /* 15 * BPF interface for raw IR 16 */ 17 const struct bpf_prog_ops lirc_mode2_prog_ops = { 18 }; 19 20 BPF_CALL_1(bpf_rc_repeat, u32*, sample) 21 { 22 struct ir_raw_event_ctrl *ctrl; 23 24 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); 25 26 rc_repeat(ctrl->dev); 27 28 return 0; 29 } 30 31 static const struct bpf_func_proto rc_repeat_proto = { 32 .func = bpf_rc_repeat, 33 .gpl_only = true, /* rc_repeat is EXPORT_SYMBOL_GPL */ 34 .ret_type = RET_INTEGER, 35 .arg1_type = ARG_PTR_TO_CTX, 36 }; 37 38 BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode, 39 u32, toggle) 40 { 41 struct ir_raw_event_ctrl *ctrl; 42 43 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); 44 45 rc_keydown(ctrl->dev, protocol, scancode, toggle != 0); 46 47 return 0; 48 } 49 50 static const struct bpf_func_proto rc_keydown_proto = { 51 .func = bpf_rc_keydown, 52 .gpl_only = true, /* rc_keydown is EXPORT_SYMBOL_GPL */ 53 .ret_type = RET_INTEGER, 54 .arg1_type = ARG_PTR_TO_CTX, 55 .arg2_type = ARG_ANYTHING, 56 .arg3_type = ARG_ANYTHING, 57 .arg4_type = ARG_ANYTHING, 58 }; 59 60 BPF_CALL_3(bpf_rc_pointer_rel, u32*, sample, s32, rel_x, s32, rel_y) 61 { 62 struct ir_raw_event_ctrl *ctrl; 63 64 ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); 65 66 input_report_rel(ctrl->dev->input_dev, REL_X, rel_x); 67 input_report_rel(ctrl->dev->input_dev, REL_Y, rel_y); 68 input_sync(ctrl->dev->input_dev); 69 70 return 0; 71 } 72 73 static const struct bpf_func_proto rc_pointer_rel_proto = { 74 .func = bpf_rc_pointer_rel, 75 .gpl_only = true, 76 .ret_type = RET_INTEGER, 77 .arg1_type = ARG_PTR_TO_CTX, 78 .arg2_type = ARG_ANYTHING, 79 .arg3_type = ARG_ANYTHING, 80 }; 81 82 static const struct bpf_func_proto * 83 lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 84 { 85 switch (func_id) { 86 case BPF_FUNC_rc_repeat: 87 return &rc_repeat_proto; 88 case BPF_FUNC_rc_keydown: 89 return &rc_keydown_proto; 90 case BPF_FUNC_rc_pointer_rel: 91 return &rc_pointer_rel_proto; 92 case BPF_FUNC_map_lookup_elem: 93 return &bpf_map_lookup_elem_proto; 94 case BPF_FUNC_map_update_elem: 95 return &bpf_map_update_elem_proto; 96 case BPF_FUNC_map_delete_elem: 97 return &bpf_map_delete_elem_proto; 98 case BPF_FUNC_map_push_elem: 99 return &bpf_map_push_elem_proto; 100 case BPF_FUNC_map_pop_elem: 101 return &bpf_map_pop_elem_proto; 102 case BPF_FUNC_map_peek_elem: 103 return &bpf_map_peek_elem_proto; 104 case BPF_FUNC_ktime_get_ns: 105 return &bpf_ktime_get_ns_proto; 106 case BPF_FUNC_ktime_get_boot_ns: 107 return &bpf_ktime_get_boot_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 (perfmon_capable()) 114 return bpf_get_trace_printk_proto(); 115 fallthrough; 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 *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 old_array = lirc_rcu_dereference(raw->progs); 158 if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) { 159 ret = -E2BIG; 160 goto unlock; 161 } 162 163 ret = bpf_prog_array_copy(old_array, NULL, prog, 0, &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 *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 = lirc_rcu_dereference(raw->progs); 196 ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &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 rcu_read_lock(); 221 bpf_prog_run_array(rcu_dereference(raw->progs), 222 &raw->bpf_sample, bpf_prog_run); 223 rcu_read_unlock(); 224 } 225 } 226 227 /* 228 * This should be called once the rc thread has been stopped, so there can be 229 * no concurrent bpf execution. 230 * 231 * Should be called with the ir_raw_handler_lock held. 232 */ 233 void lirc_bpf_free(struct rc_dev *rcdev) 234 { 235 struct bpf_prog_array_item *item; 236 struct bpf_prog_array *array; 237 238 array = lirc_rcu_dereference(rcdev->raw->progs); 239 if (!array) 240 return; 241 242 for (item = array->items; item->prog; item++) 243 bpf_prog_put(item->prog); 244 245 bpf_prog_array_free(array); 246 } 247 248 int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) 249 { 250 struct rc_dev *rcdev; 251 int ret; 252 253 if (attr->attach_flags) 254 return -EINVAL; 255 256 rcdev = rc_dev_get_from_fd(attr->target_fd, true); 257 if (IS_ERR(rcdev)) 258 return PTR_ERR(rcdev); 259 260 ret = lirc_bpf_attach(rcdev, prog); 261 262 put_device(&rcdev->dev); 263 264 return ret; 265 } 266 267 int lirc_prog_detach(const union bpf_attr *attr) 268 { 269 struct bpf_prog *prog; 270 struct rc_dev *rcdev; 271 int ret; 272 273 if (attr->attach_flags) 274 return -EINVAL; 275 276 prog = bpf_prog_get_type(attr->attach_bpf_fd, 277 BPF_PROG_TYPE_LIRC_MODE2); 278 if (IS_ERR(prog)) 279 return PTR_ERR(prog); 280 281 rcdev = rc_dev_get_from_fd(attr->target_fd, true); 282 if (IS_ERR(rcdev)) { 283 bpf_prog_put(prog); 284 return PTR_ERR(rcdev); 285 } 286 287 ret = lirc_bpf_detach(rcdev, prog); 288 289 bpf_prog_put(prog); 290 put_device(&rcdev->dev); 291 292 return ret; 293 } 294 295 int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) 296 { 297 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); 298 struct bpf_prog_array *progs; 299 struct rc_dev *rcdev; 300 u32 cnt, flags = 0; 301 int ret; 302 303 if (attr->query.query_flags) 304 return -EINVAL; 305 306 rcdev = rc_dev_get_from_fd(attr->query.target_fd, false); 307 if (IS_ERR(rcdev)) 308 return PTR_ERR(rcdev); 309 310 if (rcdev->driver_type != RC_DRIVER_IR_RAW) { 311 ret = -EINVAL; 312 goto put; 313 } 314 315 ret = mutex_lock_interruptible(&ir_raw_handler_lock); 316 if (ret) 317 goto put; 318 319 progs = lirc_rcu_dereference(rcdev->raw->progs); 320 cnt = progs ? bpf_prog_array_length(progs) : 0; 321 322 if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) { 323 ret = -EFAULT; 324 goto unlock; 325 } 326 327 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) { 328 ret = -EFAULT; 329 goto unlock; 330 } 331 332 if (attr->query.prog_cnt != 0 && prog_ids && cnt) 333 ret = bpf_prog_array_copy_to_user(progs, prog_ids, 334 attr->query.prog_cnt); 335 336 unlock: 337 mutex_unlock(&ir_raw_handler_lock); 338 put: 339 put_device(&rcdev->dev); 340 341 return ret; 342 } 343