// SPDX-License-Identifier: GPL-2.0 // bpf-lirc.c - handles bpf // // Copyright (C) 2018 Sean Young <sean@mess.org> #include <linux/bpf.h> #include <linux/filter.h> #include <linux/bpf_lirc.h> #include "rc-core-priv.h" #define lirc_rcu_dereference(p) \ rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock)) /* * BPF interface for raw IR */ const struct bpf_prog_ops lirc_mode2_prog_ops = { }; BPF_CALL_1(bpf_rc_repeat, u32*, sample) { struct ir_raw_event_ctrl *ctrl; ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); rc_repeat(ctrl->dev); return 0; } static const struct bpf_func_proto rc_repeat_proto = { .func = bpf_rc_repeat, .gpl_only = true, /* rc_repeat is EXPORT_SYMBOL_GPL */ .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, }; BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode, u32, toggle) { struct ir_raw_event_ctrl *ctrl; ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); rc_keydown(ctrl->dev, protocol, scancode, toggle != 0); return 0; } static const struct bpf_func_proto rc_keydown_proto = { .func = bpf_rc_keydown, .gpl_only = true, /* rc_keydown is EXPORT_SYMBOL_GPL */ .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_ANYTHING, .arg3_type = ARG_ANYTHING, .arg4_type = ARG_ANYTHING, }; BPF_CALL_3(bpf_rc_pointer_rel, u32*, sample, s32, rel_x, s32, rel_y) { struct ir_raw_event_ctrl *ctrl; ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample); input_report_rel(ctrl->dev->input_dev, REL_X, rel_x); input_report_rel(ctrl->dev->input_dev, REL_Y, rel_y); input_sync(ctrl->dev->input_dev); return 0; } static const struct bpf_func_proto rc_pointer_rel_proto = { .func = bpf_rc_pointer_rel, .gpl_only = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_ANYTHING, .arg3_type = ARG_ANYTHING, }; static const struct bpf_func_proto * lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_rc_repeat: return &rc_repeat_proto; case BPF_FUNC_rc_keydown: return &rc_keydown_proto; case BPF_FUNC_rc_pointer_rel: return &rc_pointer_rel_proto; case BPF_FUNC_map_lookup_elem: return &bpf_map_lookup_elem_proto; case BPF_FUNC_map_update_elem: return &bpf_map_update_elem_proto; case BPF_FUNC_map_delete_elem: return &bpf_map_delete_elem_proto; case BPF_FUNC_map_push_elem: return &bpf_map_push_elem_proto; case BPF_FUNC_map_pop_elem: return &bpf_map_pop_elem_proto; case BPF_FUNC_map_peek_elem: return &bpf_map_peek_elem_proto; case BPF_FUNC_ktime_get_ns: return &bpf_ktime_get_ns_proto; case BPF_FUNC_ktime_get_boot_ns: return &bpf_ktime_get_boot_ns_proto; case BPF_FUNC_tail_call: return &bpf_tail_call_proto; case BPF_FUNC_get_prandom_u32: return &bpf_get_prandom_u32_proto; case BPF_FUNC_trace_printk: if (perfmon_capable()) return bpf_get_trace_printk_proto(); fallthrough; default: return NULL; } } static bool lirc_mode2_is_valid_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { /* We have one field of u32 */ return type == BPF_READ && off == 0 && size == sizeof(u32); } const struct bpf_verifier_ops lirc_mode2_verifier_ops = { .get_func_proto = lirc_mode2_func_proto, .is_valid_access = lirc_mode2_is_valid_access }; #define BPF_MAX_PROGS 64 static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) { struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; struct ir_raw_event_ctrl *raw; int ret; if (rcdev->driver_type != RC_DRIVER_IR_RAW) return -EINVAL; ret = mutex_lock_interruptible(&ir_raw_handler_lock); if (ret) return ret; raw = rcdev->raw; if (!raw) { ret = -ENODEV; goto unlock; } old_array = lirc_rcu_dereference(raw->progs); if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) { ret = -E2BIG; goto unlock; } ret = bpf_prog_array_copy(old_array, NULL, prog, 0, &new_array); if (ret < 0) goto unlock; rcu_assign_pointer(raw->progs, new_array); bpf_prog_array_free(old_array); unlock: mutex_unlock(&ir_raw_handler_lock); return ret; } static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) { struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; struct ir_raw_event_ctrl *raw; int ret; if (rcdev->driver_type != RC_DRIVER_IR_RAW) return -EINVAL; ret = mutex_lock_interruptible(&ir_raw_handler_lock); if (ret) return ret; raw = rcdev->raw; if (!raw) { ret = -ENODEV; goto unlock; } old_array = lirc_rcu_dereference(raw->progs); ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &new_array); /* * Do not use bpf_prog_array_delete_safe() as we would end up * with a dummy entry in the array, and the we would free the * dummy in lirc_bpf_free() */ if (ret) goto unlock; rcu_assign_pointer(raw->progs, new_array); bpf_prog_array_free(old_array); bpf_prog_put(prog); unlock: mutex_unlock(&ir_raw_handler_lock); return ret; } void lirc_bpf_run(struct rc_dev *rcdev, u32 sample) { struct ir_raw_event_ctrl *raw = rcdev->raw; raw->bpf_sample = sample; if (raw->progs) BPF_PROG_RUN_ARRAY(raw->progs, &raw->bpf_sample, bpf_prog_run); } /* * This should be called once the rc thread has been stopped, so there can be * no concurrent bpf execution. * * Should be called with the ir_raw_handler_lock held. */ void lirc_bpf_free(struct rc_dev *rcdev) { struct bpf_prog_array_item *item; struct bpf_prog_array *array; array = lirc_rcu_dereference(rcdev->raw->progs); if (!array) return; for (item = array->items; item->prog; item++) bpf_prog_put(item->prog); bpf_prog_array_free(array); } int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) { struct rc_dev *rcdev; int ret; if (attr->attach_flags) return -EINVAL; rcdev = rc_dev_get_from_fd(attr->target_fd); if (IS_ERR(rcdev)) return PTR_ERR(rcdev); ret = lirc_bpf_attach(rcdev, prog); put_device(&rcdev->dev); return ret; } int lirc_prog_detach(const union bpf_attr *attr) { struct bpf_prog *prog; struct rc_dev *rcdev; int ret; if (attr->attach_flags) return -EINVAL; prog = bpf_prog_get_type(attr->attach_bpf_fd, BPF_PROG_TYPE_LIRC_MODE2); if (IS_ERR(prog)) return PTR_ERR(prog); rcdev = rc_dev_get_from_fd(attr->target_fd); if (IS_ERR(rcdev)) { bpf_prog_put(prog); return PTR_ERR(rcdev); } ret = lirc_bpf_detach(rcdev, prog); bpf_prog_put(prog); put_device(&rcdev->dev); return ret; } int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) { __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); struct bpf_prog_array *progs; struct rc_dev *rcdev; u32 cnt, flags = 0; int ret; if (attr->query.query_flags) return -EINVAL; rcdev = rc_dev_get_from_fd(attr->query.target_fd); if (IS_ERR(rcdev)) return PTR_ERR(rcdev); if (rcdev->driver_type != RC_DRIVER_IR_RAW) { ret = -EINVAL; goto put; } ret = mutex_lock_interruptible(&ir_raw_handler_lock); if (ret) goto put; progs = lirc_rcu_dereference(rcdev->raw->progs); cnt = progs ? bpf_prog_array_length(progs) : 0; if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) { ret = -EFAULT; goto unlock; } if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) { ret = -EFAULT; goto unlock; } if (attr->query.prog_cnt != 0 && prog_ids && cnt) ret = bpf_prog_array_copy_to_user(progs, prog_ids, attr->query.prog_cnt); unlock: mutex_unlock(&ir_raw_handler_lock); put: put_device(&rcdev->dev); return ret; }