wifi: wilc1000: validate length of IEEE80211_P2P_ATTR_OPER_CHANNEL attribute

Validate that the IEEE80211_P2P_ATTR_OPER_CHANNEL attribute contains
enough space for a 'struct struct wilc_attr_oper_ch'. If the attribute is
too small then it triggers an out-of-bounds write later in the function.

Signed-off-by: Phil Turnbull <philipturnbull@github.com>
Tested-by: Ajay Kathat <ajay.kathat@microchip.com>
Acked-by: Ajay Kathat <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221123153543.8568-3-philipturnbull@github.com

diff --git a/drivers/net/wireless/microchip/wilc1000/cfg80211.c b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
index 9bbfff8..aedf0e8 100644 (file)
--- a/drivers/net/wireless/microchip/wilc1000/cfg80211.c
+++ b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
@@ -959,14 +959,24 @@ static inline void wilc_wfi_cfg_parse_ch_attr(u8 *buf, u32 len, u8 sta_ch)
                return;
 
        while (index + sizeof(*e) <= len) {
+               u16 attr_size;
+
                e = (struct wilc_attr_entry *)&buf[index];
+               attr_size = le16_to_cpu(e->attr_len);
+
+               if (index + sizeof(*e) + attr_size > len)
+                       return;
+
                if (e->attr_type == IEEE80211_P2P_ATTR_CHANNEL_LIST)
                        ch_list_idx = index;
-               else if (e->attr_type == IEEE80211_P2P_ATTR_OPER_CHANNEL)
+               else if (e->attr_type == IEEE80211_P2P_ATTR_OPER_CHANNEL &&
+                        attr_size == (sizeof(struct wilc_attr_oper_ch) - sizeof(*e)))
                        op_ch_idx = index;
+
                if (ch_list_idx && op_ch_idx)
                        break;
-               index += le16_to_cpu(e->attr_len) + sizeof(*e);
+
+               index += sizeof(*e) + attr_size;
        }
 
        if (ch_list_idx) {