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081e4c478a
Permissions (Part 2) Description: In kernel builds, any unprivileged process running on the NuttX device can open /dev/efuse and attempt to read/write fuse content. Reading the fuses may provide valuable information to an attacker controlling the user process. The write operation, in extreme cases where the fuse blocks are not locked, may brick the device. DISCLAIMER: I tried to be strict with the settings, better to relax them later if it's needed. This is part of https://github.com/apache/nuttx/issues/19410 See https://github.com/apache/nuttx/issues/19410 Compiles ok. Signed-off-by: Catalin Visinescu <catalin_visinescu@yahoo.com>
394 lines
12 KiB
C
394 lines
12 KiB
C
/****************************************************************************
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* drivers/sensors/mcp9844.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/* WARNING for developers:
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*
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* This driver uses the legacy style of writing sensor drivers for NuttX. The
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* project has since decided to adopt a new sensor framework in order to
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* have a consistent API and feature-set.
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*
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* Sensors which use the uORB framework are typically suffixed "_uorb". You
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* can also visit the documentation about the new sensor framework to learn
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* more.
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*/
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#warning "This is a deprecated legacy sensor driver."
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/debug.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/i2c/i2c_master.h>
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#include <nuttx/sensors/mcp9844.h>
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#include <nuttx/random.h>
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#if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_MCP9844)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct mcp9844_dev_s
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{
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FAR struct i2c_master_s *i2c; /* I2C interface */
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uint8_t addr; /* I2C address */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/* I2C helper functions */
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static int mcp9844_read_u16(FAR struct mcp9844_dev_s *priv,
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uint8_t const regaddr, FAR uint16_t *value);
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static int mcp9844_write_u16(FAR struct mcp9844_dev_s *priv,
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uint8_t const regaddr,
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uint16_t const regval);
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/* Character driver methods */
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static ssize_t mcp9844_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t mcp9844_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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static int mcp9844_ioctl(FAR struct file *filep, int cmd,
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unsigned long arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_mcp9844_fops =
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{
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NULL, /* open */
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NULL, /* close */
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mcp9844_read, /* read */
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mcp9844_write, /* write */
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NULL, /* seek */
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mcp9844_ioctl, /* ioctl */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: mcp9844_read_u16
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*
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* Description:
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* Read a 16 bit value from the MCP9844 at the address regaddr.
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*
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****************************************************************************/
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static int mcp9844_read_u16(FAR struct mcp9844_dev_s *priv,
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uint8_t const regaddr, FAR uint16_t *value)
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{
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struct i2c_config_s config;
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uint8_t buffer[2];
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int ret = -1;
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/* Set up the I2C configuration */
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config.frequency = CONFIG_MCP9844_I2C_FREQUENCY;
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config.address = priv->addr;
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config.addrlen = 7;
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/* Write the register address */
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ret = i2c_write(priv->i2c, &config, ®addr, 1);
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if (ret < 0)
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{
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snerr ("i2c_write failed: %d\n", ret);
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return ret;
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}
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/* Restart and read 16-bits from the register */
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ret = i2c_read(priv->i2c, &config, buffer, 2);
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if (ret < 0)
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{
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snerr ("i2c_read failed: %d\n", ret);
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return ret;
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}
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/* Copy the content of the buffer to the location of the uint16_t pointer */
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*value = (((uint16_t)(buffer[0])) << 8) + ((uint16_t)(buffer[1]));
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sninfo("addr: %02x value: %08x ret: %d\n", regaddr, *value, ret);
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return OK;
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}
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/****************************************************************************
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* Name: mcp9844_write_u16
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*
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* Description:
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* Write to a 16-bit register of the MCP9844.
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*
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****************************************************************************/
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static int mcp9844_write_u16(FAR struct mcp9844_dev_s *priv,
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uint8_t const regaddr, uint16_t const regval)
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{
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struct i2c_config_s config;
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sninfo("addr: %02x value: %08x\n", regaddr, regval);
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/* Set up a 3 byte message to send */
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uint8_t const BUFFER_SIZE = 3;
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uint8_t buffer[BUFFER_SIZE];
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buffer[0] = regaddr;
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buffer[1] = (uint8_t)(regval >> 8);
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buffer[2] = (uint8_t)(regval);
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/* Set up the I2C configuration */
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config.frequency = CONFIG_MCP9844_I2C_FREQUENCY;
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config.address = priv->addr;
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config.addrlen = 7;
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/* Write the register address followed by the data (no RESTART) */
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return i2c_write(priv->i2c, &config, buffer, BUFFER_SIZE);
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}
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/****************************************************************************
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* Name: mcp9844_read
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****************************************************************************/
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static ssize_t mcp9844_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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return -ENOSYS;
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}
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/****************************************************************************
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* Name: mcp9844_write
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****************************************************************************/
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static ssize_t mcp9844_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen)
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{
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return -ENOSYS;
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}
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/****************************************************************************
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* Name: lm75_ioctl
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****************************************************************************/
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static int mcp9844_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct mcp9844_dev_s *priv = inode->i_private;
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int ret = OK;
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switch (cmd)
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{
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/* Read from the ambient temperature register. Arg: uint16_t* pointer */
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case SNIOC_READTEMP:
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{
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FAR struct mcp9844_temp_arg_s *temp_result =
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(FAR struct mcp9844_temp_arg_s *)((uintptr_t)arg);
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DEBUGASSERT(temp_result != NULL);
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/* Read the ambient temperature value from the device */
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uint16_t raw_temperature = 0;
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ret = mcp9844_read_u16(priv, MCP9844_TEMP_REG, &raw_temperature);
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/* Convert from the proprietary sensor temperature data
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* representation to a more user-friendly version.
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*/
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if (ret == OK)
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{
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/* Feed sensor data to entropy pool */
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add_sensor_randomness(raw_temperature);
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/* BIT15 - 13 contain information if preset temperature values
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* have been exceeded or undercut. BIT12 is now not any longer
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* needed since we do have the sign information retrieved.
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* We do not need them for the temperature so those bits
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* need to be masked out.
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*/
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raw_temperature &= 0x0fff; /* 0x0fff = 0b 0000 1111 1111 1111 */
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/* The post comma temperature value is encoded in BIT3 to
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* BIT0
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*/
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temp_result->temp_post_comma =
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(uint8_t)(raw_temperature & 0x000f);
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/* The pre comma temperature value is encoded in BIT11 to
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* BIT4
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*/
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temp_result->temp_pre_comma = (int8_t)(raw_temperature >> 4);
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}
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else
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{
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snerr("ERROR: ioctl::SNIOC_READTEMP - mcp9844_read_u16 failed"
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" - no temperature retrieved\n");
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}
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}
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break;
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case SNIOC_SETRESOLUTION:
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{
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ret = mcp9844_write_u16(priv, MCP9844_RESO_REG, (uint16_t)(arg));
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if (ret != OK)
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{
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snerr("ERROR: ioctl::SNIOC_SETRESOLUTION - mcp9844_write_u16"
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"failed - no resolution set\n");
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}
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}
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break;
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case SNIOC_SHUTDOWN:
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{
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uint16_t config_reg;
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/* Perform a read-modify-write cycle on the config register */
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ret = mcp9844_read_u16(priv, MCP9844_CONF_REG, &config_reg);
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if (ret == OK)
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{
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config_reg |= MCP9844_CONF_REG_SHDN;
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ret = mcp9844_write_u16(priv, MCP9844_CONF_REG, config_reg);
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if (ret != OK)
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{
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snerr("ERROR: ioctl::SNIOC_SHUTDOWN - "
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"mcp9844_write_u16 failed\n");
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}
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}
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else
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{
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snerr("ERROR: ioctl::SNIOC_SHUTDOWN - "
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"mcp9844_read_u16 failed\n");
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}
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}
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break;
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case SNIOC_POWERUP:
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{
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uint16_t config_reg;
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/* Perform a read-modify-write cycle on the config register */
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ret = mcp9844_read_u16(priv, MCP9844_CONF_REG, &config_reg);
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if (ret == OK)
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{
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config_reg &= ~MCP9844_CONF_REG_SHDN;
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ret = mcp9844_write_u16(priv, MCP9844_CONF_REG, config_reg);
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if (ret != OK)
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{
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snerr("ERROR: ioctl::SNIOC_POWERUP - "
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"mcp9844_write_u16 failed\n");
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}
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}
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else
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{
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snerr("ERROR: ioctl::SNIOC_POWERUP - "
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"mcp9844_read_u16 failed\n");
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}
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}
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break;
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default:
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snerr("ERROR: Unrecognized cmd: %d\n", cmd);
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ret = -ENOTTY;
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break;
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}
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: mcp9844_register
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*
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* Description:
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* Register the MCP9844 character device as 'devpath'
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*
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* Input Parameters:
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* devpath - The full path to the driver to register. E.g., "/dev/temp0"
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* i2c - An instance of the I2C interface to use to communicate with
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* MCP9844
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* addr - The I2C address of the MCP9844.
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*
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* Returned Value:
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* Zero (OK) on success; a negated errno value on failure.
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*
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****************************************************************************/
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int mcp9844_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
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uint8_t addr)
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{
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FAR struct mcp9844_dev_s *priv;
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/* Sanity check */
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DEBUGASSERT(i2c != NULL);
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/* Initialize the MCP9844 device structure */
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priv = kmm_malloc(sizeof(struct mcp9844_dev_s));
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if (priv == NULL)
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{
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snerr("ERROR: Failed to allocate instance\n");
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return -ENOMEM;
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}
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priv->i2c = i2c;
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priv->addr = addr;
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/* Register the character driver */
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int ret = register_driver(devpath, &g_mcp9844_fops, 0600, priv);
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if (ret < 0)
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{
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snerr("ERROR: Failed to register driver: %d\n", ret);
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kmm_free(priv);
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}
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return ret;
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}
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#endif /* CONFIG_I2C && CONFIG_LM75_I2C */
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