From: Arnd Bergmann <arnd@kernel.org>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
Zhang Qilong <zhangqilong3@huawei.com>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] [v2] Input: analog - fix invalid snprintf() call
Date: Wed, 24 Mar 2021 14:19:54 +0100 [thread overview]
Message-ID: <20210324131959.2089129-1-arnd@kernel.org> (raw)
From: Arnd Bergmann <arnd@arndb.de>
Overlapping input and output arguments to snprintf() are
undefined behavior in C99:
drivers/input/joystick/analog.c: In function 'analog_name':
drivers/input/joystick/analog.c:428:3: error: 'snprintf' argument 4 overlaps destination object 'analog' [-Werror=restrict]
428 | snprintf(analog->name, sizeof(analog->name), "%s %d-hat",
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
429 | analog->name, hweight16(analog->mask & ANALOG_HATS_ALL));
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/input/joystick/analog.c:420:40: note: destination object referenced by 'restrict'-qualified argument 1 was declared here
420 | static void analog_name(struct analog *analog)
| ~~~~~~~~~~~~~~~^~~~~~
Change this function to use the simpler seq_buf interface instead.
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: use seq_buf instead of rolling my own
---
drivers/input/joystick/analog.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c
index f798922a4598..087b65ae7585 100644
--- a/drivers/input/joystick/analog.c
+++ b/drivers/input/joystick/analog.c
@@ -19,6 +19,7 @@
#include <linux/input.h>
#include <linux/gameport.h>
#include <linux/jiffies.h>
+#include <linux/seq_buf.h>
#include <linux/timex.h>
#include <linux/timekeeping.h>
@@ -419,23 +420,24 @@ static void analog_calibrate_timer(struct analog_port *port)
static void analog_name(struct analog *analog)
{
- snprintf(analog->name, sizeof(analog->name), "Analog %d-axis %d-button",
+ struct seq_buf s;
+
+ seq_buf_init(&s, analog->name, sizeof(analog->name));
+ seq_buf_printf(&s, "Analog %d-axis %d-button",
hweight8(analog->mask & ANALOG_AXES_STD),
hweight8(analog->mask & ANALOG_BTNS_STD) + !!(analog->mask & ANALOG_BTNS_CHF) * 2 +
hweight16(analog->mask & ANALOG_BTNS_GAMEPAD) + !!(analog->mask & ANALOG_HBTN_CHF) * 4);
if (analog->mask & ANALOG_HATS_ALL)
- snprintf(analog->name, sizeof(analog->name), "%s %d-hat",
- analog->name, hweight16(analog->mask & ANALOG_HATS_ALL));
+ seq_buf_printf(&s, " %d-hat",
+ hweight16(analog->mask & ANALOG_HATS_ALL));
if (analog->mask & ANALOG_HAT_FCS)
- strlcat(analog->name, " FCS", sizeof(analog->name));
+ seq_buf_printf(&s, " FCS");
if (analog->mask & ANALOG_ANY_CHF)
- strlcat(analog->name, (analog->mask & ANALOG_SAITEK) ? " Saitek" : " CHF",
- sizeof(analog->name));
+ seq_buf_printf(&s, (analog->mask & ANALOG_SAITEK) ? " Saitek" : " CHF");
- strlcat(analog->name, (analog->mask & ANALOG_GAMEPAD) ? " gamepad": " joystick",
- sizeof(analog->name));
+ seq_buf_printf(&s, (analog->mask & ANALOG_GAMEPAD) ? " gamepad": " joystick");
}
/*
--
2.29.2
reply other threads:[~2021-03-24 13:20 UTC|newest]
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