mwifiex: Fix three heap overflow at parsing element in cfg80211_ap_settings

mwifiex_update_vs_ie(),mwifiex_set_uap_rates() and
mwifiex_set_wmm_params() call memcpy() without checking
the destination size.Since the source is given from
user-space, this may trigger a heap buffer overflow.

Fix them by putting the length check before performing memcpy().

This fix addresses CVE-2019-14814,CVE-2019-14815,CVE-2019-14816.

Signed-off-by: Wen Huang <[email protected]>
Acked-by: Ganapathi Bhat <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>

Author: Wen Huang

drivers/net/wireless/marvell/mwifiex/ie.c

@@ -241,6 +241,9 @@ static int mwifiex_update_vs_ie(const u8 *ies, int ies_len,
 		}
 
 		vs_ie = (struct ieee_types_header *)vendor_ie;
+		if (le16_to_cpu(ie->ie_length) + vs_ie->len + 2 >
+			IEEE_MAX_IE_SIZE)
+			return -EINVAL;
 		memcpy(ie->ie_buffer + le16_to_cpu(ie->ie_length),
 		       vs_ie, vs_ie->len + 2);
 		le16_unaligned_add_cpu(&ie->ie_length, vs_ie->len + 2);

drivers/net/wireless/marvell/mwifiex/uap_cmd.c

@@ -265,15 +265,20 @@ mwifiex_set_uap_rates(struct mwifiex_uap_bss_param *bss_cfg,
 
 	rate_ie = (void *)cfg80211_find_ie(WLAN_EID_SUPP_RATES, var_pos, len);
 	if (rate_ie) {
+		if (rate_ie->len > MWIFIEX_SUPPORTED_RATES)
+			return;
 		memcpy(bss_cfg->rates, rate_ie + 1, rate_ie->len);
 		rate_len = rate_ie->len;
 	}
 
 	rate_ie = (void *)cfg80211_find_ie(WLAN_EID_EXT_SUPP_RATES,
 					   params->beacon.tail,
 					   params->beacon.tail_len);
-	if (rate_ie)
+	if (rate_ie) {
+		if (rate_ie->len > MWIFIEX_SUPPORTED_RATES - rate_len)
+			return;
 		memcpy(bss_cfg->rates + rate_len, rate_ie + 1, rate_ie->len);
+	}
 
 	return;
 }
@@ -391,6 +396,8 @@ mwifiex_set_wmm_params(struct mwifiex_private *priv,
 					    params->beacon.tail_len);
 	if (vendor_ie) {
 		wmm_ie = vendor_ie;
+		if (*(wmm_ie + 1) > sizeof(struct mwifiex_types_wmm_info))
+			return;
 		memcpy(&bss_cfg->wmm_info, wmm_ie +
 		       sizeof(struct ieee_types_header), *(wmm_ie + 1));
 		priv->wmm_enabled = 1;