ALSA: control-led: use strscpy in set_led_id()

commit 70051cffb31b5ee09096351c3b41fcae6f89de31 upstream.

The use of strncpy() in the set_led_id() was incorrect.
The len variable should use 'min(sizeof(buf2) - 1, count)'
expression.

Use strscpy() function to simplify things and handle the error gracefully.

Fixes: a135dfb5de15 ("ALSA: led control - add sysfs kcontrol LED marking layer")
Reported-by: yang.yang29@zte.com.cn
Link: https://lore.kernel.org/alsa-devel/202301091945513559977@zte.com.cn/
Cc: <stable@vger.kernel.org>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/core/control_led.c b/sound/core/control_led.c
index a95332b..3eb1c5a 100644 (file)
--- a/sound/core/control_led.c
+++ b/sound/core/control_led.c
@@ -530,12 +530,11 @@ static ssize_t set_led_id(struct snd_ctl_led_card *led_card, const char *buf, si
                          bool attach)
 {
        char buf2[256], *s, *os;
-       size_t len = max(sizeof(s) - 1, count);
        struct snd_ctl_elem_id id;
        int err;
 
-       strncpy(buf2, buf, len);
-       buf2[len] = '\0';
+       if (strscpy(buf2, buf, sizeof(buf2)) < 0)
+               return -E2BIG;
        memset(&id, 0, sizeof(id));
        id.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
        s = buf2;