[PATCH v2] iio: multiplexer: fix unsigned check with less than zero

From: Peter Rosin
Date: Wed Mar 08 2017 - 08:27:49 EST


Comparing a size_t with less than zero is always false as size_t
is unsigned. So, change the type of the variable to ssize_t and
replicate the size check from mux_configure_channel() into
mux_write_ext_info() thus ensuring that the size will fit in the
ssize_t variable.

Detected by CoverityScan, CID#1415278 ("Unsigned compared against 0")

Reported-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
---
drivers/iio/multiplexer/iio-mux.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

Hi!

Here's what intend to queue up.

Cheers,
peda

diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c
index 94d40f9b..bab9e69 100644
--- a/drivers/iio/multiplexer/iio-mux.c
+++ b/drivers/iio/multiplexer/iio-mux.c
@@ -21,7 +21,7 @@

struct mux_ext_info_cache {
char *data;
- size_t size;
+ ssize_t size;
};

struct mux_child {
@@ -206,6 +206,9 @@ static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private,
char *new;
ssize_t ret;

+ if (len >= PAGE_SIZE)
+ return -EINVAL;
+
ret = iio_mux_select(mux, idx);
if (ret < 0)
return ret;
--
2.1.4