hwmon: (ibmpowernv) Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>

Author: tiwai

drivers/hwmon/ibmpowernv.c

@@ -186,7 +186,7 @@ static void make_sensor_label(struct device_node *np,
 	u32 id;
 	size_t n;
 
-	n = snprintf(sdata->label, sizeof(sdata->label), "%s", label);
+	n = scnprintf(sdata->label, sizeof(sdata->label), "%s", label);
 
 	/*
 	 * Core temp pretty print
@@ -199,19 +199,19 @@ static void make_sensor_label(struct device_node *np,
 			 * The digital thermal sensors are associated
 			 * with a core.
 			 */
-			n += snprintf(sdata->label + n,
+			n += scnprintf(sdata->label + n,
 				      sizeof(sdata->label) - n, " %d",
 				      cpuid);
 		else
-			n += snprintf(sdata->label + n,
+			n += scnprintf(sdata->label + n,
 				      sizeof(sdata->label) - n, " phy%d", id);
 	}
 
 	/*
 	 * Membuffer pretty print
 	 */
 	if (!of_property_read_u32(np, "ibm,chip-id", &id))
-		n += snprintf(sdata->label + n, sizeof(sdata->label) - n,
+		n += scnprintf(sdata->label + n, sizeof(sdata->label) - n,
 			      " %d", id & 0xffff);
 }