mac80211: Add RX flag to indicate ICV stripped

BugLink: http://bugs.launchpad.net/bugs/1774173

commit cef0acd4 upstream.

Add a flag that indicates that the WEP ICV was stripped from an
RX packet, allowing the device to not transfer that if it's
already checked.
Signed-off-by: David Spinadel <david.spinadel@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Cc: Sriram R <srirrama@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

include/net/mac80211.h

@@ -975,7 +975,7 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  * @RX_FLAG_DECRYPTED: This frame was decrypted in hardware.
  * @RX_FLAG_MMIC_STRIPPED: the Michael MIC is stripped off this frame,
  *	verification has been done by the hardware.
- * @RX_FLAG_IV_STRIPPED: The IV/ICV are stripped from this frame.
+ * @RX_FLAG_IV_STRIPPED: The IV and ICV are stripped from this frame.
  *	If this flag is set, the stack cannot do any replay detection
  *	hence the driver or hardware will have to do that.
  * @RX_FLAG_PN_VALIDATED: Currently only valid for CCMP/GCMP frames, this
@@ -1034,6 +1034,8 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  * @RX_FLAG_ALLOW_SAME_PN: Allow the same PN as same packet before.
  *	This is used for AMSDU subframes which can have the same PN as
  *	the first subframe.
+ * @RX_FLAG_ICV_STRIPPED: The ICV is stripped from this frame. CRC checking must
+ *	be done in the hardware.
  */
 enum mac80211_rx_flags {
 	RX_FLAG_MMIC_ERROR		= BIT(0),
@@ -1066,6 +1068,7 @@ enum mac80211_rx_flags {
 	RX_FLAG_RADIOTAP_VENDOR_DATA	= BIT(31),
 	RX_FLAG_MIC_STRIPPED		= BIT_ULL(32),
 	RX_FLAG_ALLOW_SAME_PN		= BIT_ULL(33),
+	RX_FLAG_ICV_STRIPPED		= BIT_ULL(34),
 };
 
 #define RX_FLAG_STBC_SHIFT		26

net/mac80211/wep.c

@@ -293,7 +293,8 @@ ieee80211_crypto_wep_decrypt(struct ieee80211_rx_data *rx)
 			return RX_DROP_UNUSABLE;
 		ieee80211_wep_remove_iv(rx->local, rx->skb, rx->key);
 		/* remove ICV */
-		if (pskb_trim(rx->skb, rx->skb->len - IEEE80211_WEP_ICV_LEN))
+		if (!(status->flag & RX_FLAG_ICV_STRIPPED) &&
+		    pskb_trim(rx->skb, rx->skb->len - IEEE80211_WEP_ICV_LEN))
 			return RX_DROP_UNUSABLE;
 	}
 

net/mac80211/wpa.c

@@ -298,7 +298,8 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
 		return RX_DROP_UNUSABLE;
 
 	/* Trim ICV */
-	skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN);
+	if (!(status->flag & RX_FLAG_ICV_STRIPPED))
+		skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN);
 
 	/* Remove IV */
 	memmove(skb->data + IEEE80211_TKIP_IV_LEN, skb->data, hdrlen);