When user issues a connection with a different SSID than the one
virt_wifi has advertised, the __cfg80211_connect_result() will
trigger the warning: WARN_ON(bss_not_found).
The issue is because the connection code in virt_wifi does not
check the SSID from user space (it only checks the BSSID), and
virt_wifi will call cfg80211_connect_result() with WLAN_STATUS_SUCCESS
even if the SSID is different from the one virt_wifi has advertised.
Eventually cfg80211 won't be able to find the cfg80211_bss and generate
the warning.
Fixed it by checking the SSID (from user space) in the connection code.
Fixes: c7cdba31ed8b ("mac80211-next: rtnetlink wifi simulation device")
Reported-by: syzbot+d6eb9cee2885ec06f5e3@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: En-Wei Wu <en-wei.wu@xxxxxxxxxxxxx>
---
drivers/net/wireless/virtual/virt_wifi.c | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/virtual/virt_wifi.c b/drivers/net/wireless/virtual/virt_wifi.c
index 6a84ec58d618..86a8f74be654 100644
--- a/drivers/net/wireless/virtual/virt_wifi.c
+++ b/drivers/net/wireless/virtual/virt_wifi.c
@@ -136,6 +136,9 @@ static struct ieee80211_supported_band band_5ghz = {
/* Assigned at module init. Guaranteed locally-administered and unicast. */
static u8 fake_router_bssid[ETH_ALEN] __ro_after_init = {};
+#define VIRT_WIFI_SSID_LEN 8
+#define VIRT_WIFI_SSID "VirtWifi"
+
static void virt_wifi_inform_bss(struct wiphy *wiphy)
{
u64 tsf = div_u64(ktime_get_boottime_ns(), 1000);
@@ -146,8 +149,8 @@ static void virt_wifi_inform_bss(struct wiphy *wiphy)
u8 ssid[8];
} __packed ssid = {
.tag = WLAN_EID_SSID,
- .len = 8,
- .ssid = "VirtWifi",
+ .len = VIRT_WIFI_SSID_LEN,
+ .ssid = VIRT_WIFI_SSID,
};
informed_bss = cfg80211_inform_bss(wiphy, &channel_5ghz,
@@ -213,6 +216,8 @@ struct virt_wifi_netdev_priv {
struct net_device *upperdev;
u32 tx_packets;
u32 tx_failed;
+ u32 connect_requested_ssid_len;
+ u8 connect_requested_ssid[IEEE80211_MAX_SSID_LEN];
u8 connect_requested_bss[ETH_ALEN];
bool is_up;
bool is_connected;
@@ -224,11 +229,21 @@ static int virt_wifi_connect(struct wiphy *wiphy, struct net_device *netdev,
struct cfg80211_connect_params *sme)
{
struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
+ u32 ssid_len;
bool could_schedule;
if (priv->being_deleted || !priv->is_up)
return -EBUSY;
+ if (!sme->ssid) {
+ wiphy_err(wiphy, "invalid SSID\n");
+ return -EINVAL;
+ }
+
+ ssid_len = min_t(u32, sme->ssid_len, IEEE80211_MAX_SSID_LEN);
+ priv->connect_requested_ssid_len = ssid_len;
+ memcpy(priv->connect_requested_ssid, sme->ssid, ssid_len);
+
could_schedule = schedule_delayed_work(&priv->connect, HZ * 2);
if (!could_schedule)
return -EBUSY;
@@ -252,12 +267,15 @@ static void virt_wifi_connect_complete(struct work_struct *work)
container_of(work, struct virt_wifi_netdev_priv, connect.work);
u8 *requested_bss = priv->connect_requested_bss;
bool right_addr = ether_addr_equal(requested_bss, fake_router_bssid);
+ bool right_ssid = (priv->connect_requested_ssid_len == VIRT_WIFI_SSID_LEN ?
+ !memcmp(priv->connect_requested_ssid, VIRT_WIFI_SSID,
+ priv->connect_requested_ssid_len) : false);
u16 status = WLAN_STATUS_SUCCESS;
if (is_zero_ether_addr(requested_bss))
requested_bss = NULL;
- if (!priv->is_up || (requested_bss && !right_addr))
+ if (!priv->is_up || (requested_bss && !right_addr) || !right_ssid)
status = WLAN_STATUS_UNSPECIFIED_FAILURE;
else
priv->is_connected = true;
--
2.43.0
