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w1: IAD Register is yet readable trough iad sys file. Fix snprintf (%u for unsigned, count for max size). 

IAD Register is yet readable trough the "iad" sys file.

A write to the "iad" sys file enables or disables the current
measurement, but it was not possible to get the measured value by
reading it.
Fix: %u in snprintf for unsigned values (vdd and vad)
Fix: Avoid possibles overflows (Usage of the 'count' variables)

Signed-off-by: Julien Folly <julien.folly@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Julien Folly 2018-10-09 19:47:45 +02:00 committed by Greg Kroah-Hartman
parent 3c3f76248e
commit 6eaafbb699
1 changed files with 52 additions and 14 deletions
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66
drivers/w1/slaves/w1_ds2438.c
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@ -186,8 +186,8 @@ static int w1_ds2438_change_config_bit(struct w1_slave *sl, u8 mask, u8 value)
return -1;
}
static uint16_t w1_ds2438_get_voltage(struct w1_slave *sl,
int adc_input, uint16_t *voltage)
static int w1_ds2438_get_voltage(struct w1_slave *sl,
int adc_input, uint16_t *voltage)
{
unsigned int retries = W1_DS2438_RETRIES;
u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
@ -235,6 +235,25 @@ static uint16_t w1_ds2438_get_voltage(struct w1_slave *sl,
return ret;
}
static int w1_ds2438_get_current(struct w1_slave *sl, int16_t *voltage)
{
u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
int ret;
mutex_lock(&sl->master->bus_mutex);
if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
/* The voltage measured across current sense resistor RSENS. */
*voltage = (((int16_t) w1_buf[DS2438_CURRENT_MSB]) << 8) | ((int16_t) w1_buf[DS2438_CURRENT_LSB]);
ret = 0;
} else
ret = -1;
mutex_unlock(&sl->master->bus_mutex);
return ret;
}
static ssize_t iad_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
@ -257,6 +276,27 @@ static ssize_t iad_write(struct file *filp, struct kobject *kobj,
return ret;
}
static ssize_t iad_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int ret;
int16_t voltage;
if (off != 0)
return 0;
if (!buf)
return -EINVAL;
if (w1_ds2438_get_current(sl, &voltage) == 0) {
ret = snprintf(buf, count, "%i\n", voltage);
} else
ret = -EIO;
return ret;
}
static ssize_t page0_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
@ -272,9 +312,13 @@ static ssize_t page0_read(struct file *filp, struct kobject *kobj,
mutex_lock(&sl->master->bus_mutex);
/* Read no more than page0 size */
if (count > DS2438_PAGE_SIZE)
count = DS2438_PAGE_SIZE;
if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
memcpy(buf, &w1_buf, DS2438_PAGE_SIZE);
ret = DS2438_PAGE_SIZE;
memcpy(buf, &w1_buf, count);
ret = count;
} else
ret = -EIO;
@ -289,7 +333,6 @@ static ssize_t temperature_read(struct file *filp, struct kobject *kobj,
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int ret;
ssize_t c = PAGE_SIZE;
int16_t temp;
if (off != 0)
@ -298,8 +341,7 @@ static ssize_t temperature_read(struct file *filp, struct kobject *kobj,
return -EINVAL;
if (w1_ds2438_get_temperature(sl, &temp) == 0) {
c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", temp);
ret = PAGE_SIZE - c;
ret = snprintf(buf, count, "%i\n", temp);
} else
ret = -EIO;
@ -312,7 +354,6 @@ static ssize_t vad_read(struct file *filp, struct kobject *kobj,
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int ret;
ssize_t c = PAGE_SIZE;
uint16_t voltage;
if (off != 0)
@ -321,8 +362,7 @@ static ssize_t vad_read(struct file *filp, struct kobject *kobj,
return -EINVAL;
if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, &voltage) == 0) {
c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
ret = PAGE_SIZE - c;
ret = snprintf(buf, count, "%u\n", voltage);
} else
ret = -EIO;
@ -335,7 +375,6 @@ static ssize_t vdd_read(struct file *filp, struct kobject *kobj,
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int ret;
ssize_t c = PAGE_SIZE;
uint16_t voltage;
if (off != 0)
@ -344,15 +383,14 @@ static ssize_t vdd_read(struct file *filp, struct kobject *kobj,
return -EINVAL;
if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, &voltage) == 0) {
c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
ret = PAGE_SIZE - c;
ret = snprintf(buf, count, "%u\n", voltage);
} else
ret = -EIO;
return ret;
}
static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, NULL, iad_write, 1);
static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, iad_read, iad_write, 0);
static BIN_ATTR_RO(page0, DS2438_PAGE_SIZE);
static BIN_ATTR_RO(temperature, 0/* real length varies */);
static BIN_ATTR_RO(vad, 0/* real length varies */);