nl80211 driver: correctly set the encrypt bit for eapol frames

A recent kernel change led to all EAPOL frames being encrypted rather than
just those for the group handshake. This is due to transmit processing in
the kernel now using the proper interface which would encrypt those frames
with the group key because hostapd wasn't requesting that they not be
encrypted. This changes the nl80211 driver to not request encryption unless
the EAPOL frame should be encrypted.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

hostapd/driver_nl80211.c

@@ -405,14 +405,14 @@ static int i802_set_ssid(const char *ifname, void *priv, const u8 *buf,
 }
 
 
-static int i802_send_mgmt_frame(void *priv, const void *data, size_t len,
-				int flags)
+static int i802_send_frame(void *priv, const void *data, size_t len,
+			   int encrypt, int flags)
 {
 	__u8 rtap_hdr[] = {
 		0x00, 0x00, /* radiotap version */
 		0x0e, 0x00, /* radiotap length */
 		0x02, 0xc0, 0x00, 0x00, /* bmap: flags, tx and rx flags */
-		0x0c,       /* F_WEP | F_FRAG (encrypt/fragment if required) */
+		IEEE80211_RADIOTAP_F_FRAG, /* F_FRAG (fragment if required) */
 		0x00,       /* padding */
 		0x00, 0x00, /* RX and TX flags to indicate that */
 		0x00, 0x00, /* this is the injected frame directly */
@@ -438,9 +438,17 @@ static int i802_send_mgmt_frame(void *priv, const void *data, size_t len,
 		.msg_flags = 0,
 	};
 
+	if (encrypt)
+		rtap_hdr[8] |= IEEE80211_RADIOTAP_F_WEP;
+
 	return sendmsg(drv->monitor_sock, &msg, flags);
 }
 
+static int i802_send_mgmt_frame(void *priv, const void *data, size_t len,
+				int flags)
+{
+	return i802_send_frame(priv, data, len, 1, flags);
+}
 
 /* Set kernel driver on given frequency (MHz) */
 static int i802_set_freq(void *priv, int mode, int freq)
@@ -771,7 +779,7 @@ static int i802_send_eapol(void *priv, const u8 *addr, const u8 *data,
 	pos += 2;
 	memcpy(pos, data, data_len);
 
-	res = i802_send_mgmt_frame(drv, (u8 *) hdr, len, 0);
+	res = i802_send_frame(drv, (u8 *) hdr, len, encrypt, 0);
 	free(hdr);
 
 	if (res < 0) {