[PATCH] [RESEND] [v2] Input: analog - fix invalid snprintf() call
From: Arnd Bergmann <arnd@kernel.org>
Date: 2021-09-27 10:14:22
Also in:
linux-input
Subsystem:
input (keyboard, mouse, joystick, touchscreen) drivers, the rest · Maintainers:
Dmitry Torokhov, Linus Torvalds
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 <redacted>
Link: https://lore.kernel.org/all/20210323131456.2600132-1-arnd@kernel.org/ (local)
Link: https://lore.kernel.org/all/20210324131959.2089129-1-arnd@kernel.org/ (local)
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: use seq_buf instead of rolling my own
Resending as the second submission somehow got dropped
---
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 882c3c8ba399..3c17bf202af5 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>
@@ -338,23 +339,24 @@ 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