krackattacks: fix group reinstallation test on patched kernels

Patched Linux kernels will not reset the transmit counter when
reinstalling the group key. However, we were counting in this
behaviour in our group key reinstallation tests. Fix this by
explicitly removing the key before installing it. This does
allow us to install the same group key using a lower transmit
counter.

src/drivers/driver_nl80211.c

@@ -38,6 +38,7 @@
 #include "rfkill.h"
 #include "driver_nl80211.h"
 
+#include "common/attacks.h"
 
 #ifndef CONFIG_LIBNL20
 /*
@@ -2663,6 +2664,13 @@ static int wpa_driver_nl80211_set_key(const char *ifname, struct i802_bss *bss,
 	if (drv->nlmode == NL80211_IFTYPE_P2P_DEVICE)
 		return 0;
 
+#ifdef KRACK_TEST_CLIENT
+	// Delete the key first to so that in patched kernels (that ignore key reinstallations), this still causes
+	// the associated transmit counter to be reset (required when testing group key reinstallations).
+	if (alg != WPA_ALG_NONE)
+		wpa_driver_nl80211_set_key(ifname, bss, WPA_ALG_NONE, addr, key_idx, set_tx, seq, seq_len, key, key_len);
+#endif // KRACK_TEST_CLIENT
+
 	ifindex = if_nametoindex(ifname);
 	wpa_printf(MSG_DEBUG, "%s: ifindex=%d (%s) alg=%d addr=%p key_idx=%d "
 		   "set_tx=%d seq_len=%lu key_len=%lu",