[PATCH 4.19 08/88] hwmon: (applesmc) check status earlier.

Greg Kroah-Hartman
2020-09-08T18:41:36Z

From: Tom Rix <trix@redhat.com>

[ Upstream commit cecf7560f00a8419396a2ed0f6e5d245ccb4feac ]

clang static analysis reports this representative problem

applesmc.c:758:10: warning: 1st function call argument is an
uninitialized value
left = be16_to_cpu(*(__be16 *)(buffer + 6)) >> 2;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

buffer is filled by the earlier call

ret = applesmc_read_key(LIGHT_SENSOR_LEFT_KEY, ...

This problem is reported because a goto skips the status check.
Other similar problems use data from applesmc_read_key before checking
the status. So move the checks to before the use.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Henrik Rydberg <rydberg@bitmath.org>
Link: https://lore.kernel.org/r/20200820131932.10590-1-trix@redhat.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/applesmc.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index 5c677ba440143..b201129a9beae 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -760,15 +760,18 @@ static ssize_t applesmc_light_show(struct device *dev,
}

ret = applesmc_read_key(LIGHT_SENSOR_LEFT_KEY, buffer, data_length);
+ if (ret)
+ goto out;
/* newer macbooks report a single 10-bit bigendian value */
if (data_length == 10) {
left = be16_to_cpu(*(__be16 *)(buffer + 6)) >> 2;
goto out;
}
left = buffer[2];
+
+ ret = applesmc_read_key(LIGHT_SENSOR_RIGHT_KEY, buffer, data_length);
if (ret)
goto out;
- ret = applesmc_read_key(LIGHT_SENSOR_RIGHT_KEY, buffer, data_length);
right = buffer[2];

out:
@@ -817,12 +820,11 @@ static ssize_t applesmc_show_fan_speed(struct device *dev,
to_index(attr));

ret = applesmc_read_key(newkey, buffer, 2);
- speed = ((buffer[0] << 8 | buffer[1]) >> 2);
-
if (ret)
return ret;
- else
- return snprintf(sysfsbuf, PAGE_SIZE, "%u\n", speed);
+
+ speed = ((buffer[0] << 8 | buffer[1]) >> 2);
+ return snprintf(sysfsbuf, PAGE_SIZE, "%u\n", speed);
}

static ssize_t applesmc_store_fan_speed(struct device *dev,
@@ -858,12 +860,11 @@ static ssize_t applesmc_show_fan_manual(struct device *dev,
u8 buffer[2];

ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
- manual = ((buffer[0] << 8 | buffer[1]) >> to_index(attr)) & 0x01;
-
if (ret)
return ret;
- else
- return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", manual);
+
+ manual = ((buffer[0] << 8 | buffer[1]) >> to_index(attr)) & 0x01;
+ return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", manual);
}

static ssize_t applesmc_store_fan_manual(struct device *dev,
@@ -879,10 +880,11 @@ static ssize_t applesmc_store_fan_manual(struct device *dev,
return -EINVAL;

ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
- val = (buffer[0] << 8 | buffer[1]);
if (ret)
goto out;

+ val = (buffer[0] << 8 | buffer[1]);
+
if (input)
val = val | (0x01 << to_index(attr));
else
@@ -958,13 +960,12 @@ static ssize_t applesmc_key_count_show(struct device *dev,
u32 count;

ret = applesmc_read_key(KEY_COUNT_KEY, buffer, 4);
- count = ((u32)buffer[0]<<24) + ((u32)buffer[1]<<16) +
- ((u32)buffer[2]<<8) + buffer[3];
-
if (ret)
return ret;
- else
- return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", count);
+
+ count = ((u32)buffer[0]<<24) + ((u32)buffer[1]<<16) +
+ ((u32)buffer[2]<<8) + buffer[3];
+ return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", count);
}

static ssize_t applesmc_key_at_index_read_show(struct device *dev,
--
2.25.1