staging: rtl8192u: ieee80211: Replace snprintf with scnprintf

When the number of bytes to be printed exceeds the limit snprintf
returns the number of bytes that would have been printed (if there was
no truncation). This might cause issues, hence use scnprintf which
returns the actual number of bytes printed to buffer always.
Signed-off-by: Rohit Sarkar <rohitsarkar5398@gmail.com>
Link: https://lore.kernel.org/r/20190910182415.GA5768@SARKARSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c

@@ -1620,7 +1620,7 @@ int ieee80211_parse_info_param(struct ieee80211_device *ieee,
 			for (i = 0; i < network->rates_len; i++) {
 				network->rates[i] = info_element->data[i];
 #ifdef CONFIG_IEEE80211_DEBUG
-				p += snprintf(p, sizeof(rates_str) -
+				p += scnprintf(p, sizeof(rates_str) -
 					      (p - rates_str), "%02X ",
 					      network->rates[i]);
 #endif
@@ -1647,7 +1647,7 @@ int ieee80211_parse_info_param(struct ieee80211_device *ieee,
 			for (i = 0; i < network->rates_ex_len; i++) {
 				network->rates_ex[i] = info_element->data[i];
 #ifdef CONFIG_IEEE80211_DEBUG
-				p += snprintf(p, sizeof(rates_str) -
+				p += scnprintf(p, sizeof(rates_str) -
 					      (p - rates_str), "%02X ",
 					      network->rates_ex[i]);
 #endif

drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c

@@ -109,7 +109,7 @@ static inline char *rtl819x_translate_scan(struct ieee80211_device *ieee,
 	/* Add basic and extended rates */
 	max_rate = 0;
 	p = custom;
-	p += snprintf(p, MAX_CUSTOM_LEN - (p - custom), " Rates (Mb/s): ");
+	p += scnprintf(p, MAX_CUSTOM_LEN - (p - custom), " Rates (Mb/s): ");
 	for (i = 0, j = 0; i < network->rates_len; ) {
 		if (j < network->rates_ex_len &&
 		    ((network->rates_ex[j] & 0x7F) <
@@ -119,12 +119,12 @@ static inline char *rtl819x_translate_scan(struct ieee80211_device *ieee,
 			rate = network->rates[i++] & 0x7F;
 		if (rate > max_rate)
 			max_rate = rate;
-		p += snprintf(p, MAX_CUSTOM_LEN - (p - custom),
+		p += scnprintf(p, MAX_CUSTOM_LEN - (p - custom),
 			      "%d%s ", rate >> 1, (rate & 1) ? ".5" : "");
 	}
 	for (; j < network->rates_ex_len; j++) {
 		rate = network->rates_ex[j] & 0x7F;
-		p += snprintf(p, MAX_CUSTOM_LEN - (p - custom),
+		p += scnprintf(p, MAX_CUSTOM_LEN - (p - custom),
 			      "%d%s ", rate >> 1, (rate & 1) ? ".5" : "");
 		if (rate > max_rate)
 			max_rate = rate;
@@ -214,7 +214,7 @@ static inline char *rtl819x_translate_scan(struct ieee80211_device *ieee,
 	 * for given network. */
 	iwe.cmd = IWEVCUSTOM;
 	p = custom;
-	p += snprintf(p, MAX_CUSTOM_LEN - (p - custom),
+	p += scnprintf(p, MAX_CUSTOM_LEN - (p - custom),
 		      " Last beacon: %lums ago", (jiffies - network->last_scanned) / (HZ / 100));
 	iwe.u.data.length = p - custom;
 	if (iwe.u.data.length)