drivers/media/rc/bpf-lirc.c - third_party/linux - Git at Google

 // 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"

 /*
  * 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,
 };

 /*
  * Currently rc-core does not support 64-bit scancodes, but there are many
  * known protocols with more than 32 bits. So, define the interface as u64
  * as a future-proof.
  */
 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,
 };

 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_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_ktime_get_ns:
 		return &bpf_ktime_get_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 (capable(CAP_SYS_ADMIN))
 			return bpf_get_trace_printk_proto();
 		/* fall through */
 	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 __rcu *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;
 	}

 	if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) {
 		ret = -E2BIG;
 		goto unlock;
 	}

 	old_array = raw->progs;
 	ret = bpf_prog_array_copy(old_array, NULL, prog, &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 __rcu *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 = raw->progs;
 	ret = bpf_prog_array_copy(old_array, prog, NULL, &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.
  */
 void lirc_bpf_free(struct rc_dev *rcdev)
 {
 	struct bpf_prog **progs;

 	if (!rcdev->raw->progs)
 		return;

 	progs = rcu_dereference(rcdev->raw->progs)->progs;
 	while (*progs)
 		bpf_prog_put(*progs++);

 	bpf_prog_array_free(rcdev->raw->progs);
 }

 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 __rcu *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 = 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, cnt);

 unlock:
 	mutex_unlock(&ir_raw_handler_lock);
 put:
 	put_device(&rcdev->dev);

 	return ret;
 }
	// 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"

	/*
	* 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,
	};

	/*
	* Currently rc-core does not support 64-bit scancodes, but there are many
	* known protocols with more than 32 bits. So, define the interface as u64
	* as a future-proof.
	*/
	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,
	};

	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_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_ktime_get_ns:
	return &bpf_ktime_get_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 (capable(CAP_SYS_ADMIN))
	return bpf_get_trace_printk_proto();
	/* fall through */
	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 __rcu *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;
	}

	if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) {
	ret = -E2BIG;
	goto unlock;
	}

	old_array = raw->progs;
	ret = bpf_prog_array_copy(old_array, NULL, prog, &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 __rcu *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 = raw->progs;
	ret = bpf_prog_array_copy(old_array, prog, NULL, &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.
	*/
	void lirc_bpf_free(struct rc_dev *rcdev)
	{
	struct bpf_prog **progs;

	if (!rcdev->raw->progs)
	return;

	progs = rcu_dereference(rcdev->raw->progs)->progs;
	while (*progs)
	bpf_prog_put(*progs++);

	bpf_prog_array_free(rcdev->raw->progs);
	}

	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 __rcu *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 = 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, cnt);

	unlock:
	mutex_unlock(&ir_raw_handler_lock);
	put:
	put_device(&rcdev->dev);

	return ret;
	}