| Message ID | 1457469654-17059-3-git-send-email-linux@rasmusvillemoes.dk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Mar 8, 2016 at 10:40 PM, Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote: > Passing overlapping src and dst buffers to snprintf is fragile, and > while it currently works for the special case of passing dst as the > argument corresponding to an initial "%s" in the format string, any > other use would very likely lead to chaos. It's easy enough to avoid, > so let's do that. > static void analog_name(struct analog *analog) > { > - snprintf(analog->name, sizeof(analog->name), "Analog %d-axis %d-button", > + int ret = 0; Assignment is not needed. > + > + ret = scnprintf(analog->name, sizeof(analog->name), "Analog %d-axis %d-button",
diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c index 6f8b084e13d0..d0a9b90e8f94 100644 --- a/drivers/input/joystick/analog.c +++ b/drivers/input/joystick/analog.c @@ -435,14 +435,16 @@ 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", + int ret = 0; + + ret = scnprintf(analog->name, sizeof(analog->name), "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)); + scnprintf(analog->name + ret, sizeof(analog->name) - ret, " %d-hat", + hweight16(analog->mask & ANALOG_HATS_ALL)); if (analog->mask & ANALOG_HAT_FCS) strlcat(analog->name, " FCS", sizeof(analog->name));
Passing overlapping src and dst buffers to snprintf is fragile, and while it currently works for the special case of passing dst as the argument corresponding to an initial "%s" in the format string, any other use would very likely lead to chaos. It's easy enough to avoid, so let's do that. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- drivers/input/joystick/analog.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)