mac80211: Get IV len from key conf and not cipher scheme

When a key is installed using a cipher scheme, set a new
internal key flag (KEY_FLAG_CIPHER_SCHEME) on it, to allow
distinguishing such keys more easily.

In particular, use this flag on the TX path instead of
testing the sta->cipher_scheme pointer, as the station is
NULL for broad-/multicast message, and use the key's iv_len
instead of the cipher scheme information.

Signed-off-by: Cedric Izoard <cedric.izoard@ceva-dsp.com>
[add missing documentation, rewrite commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 9 insertions, 7 deletions

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 0825d76edcfc..2291cd730091 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -492,6 +492,7 @@ ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
                                 for (j = 0; j < len; j++)
                                         key->u.gen.rx_pn[i][j] =
                                                         seq[len - j - 1];
+                        key->flags |= KEY_FLAG_CIPHER_SCHEME;
                 }
         }
         memcpy(key->conf.key, key_data, key_len);
diff --git a/net/mac80211/key.h b/net/mac80211/key.h
index d57a9915494f..c5a31835be0e 100644
--- a/net/mac80211/key.h
+++ b/net/mac80211/key.h
@@ -30,10 +30,12 @@ struct sta_info;
  * @KEY_FLAG_UPLOADED_TO_HARDWARE: Indicates that this key is present
  *      in the hardware for TX crypto hardware acceleration.
  * @KEY_FLAG_TAINTED: Key is tainted and packets should be dropped.
+ * @KEY_FLAG_CIPHER_SCHEME: This key is for a hardware cipher scheme
  */
 enum ieee80211_internal_key_flags {
         KEY_FLAG_UPLOADED_TO_HARDWARE   = BIT(0),
         KEY_FLAG_TAINTED                = BIT(1),
+        KEY_FLAG_CIPHER_SCHEME          = BIT(2),
 };
 
 enum ieee80211_internal_tkip_state {
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 75de6fac40d1..9d63d93c836e 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -780,9 +780,8 @@ ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx,
         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
         struct ieee80211_key *key = tx->key;
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-        const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme;
         int hdrlen;
-        u8 *pos;
+        u8 *pos, iv_len = key->conf.iv_len;
 
         if (info->control.hw_key &&
             !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
@@ -790,14 +789,14 @@ ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx,
                 return TX_CONTINUE;
         }
 
-        if (unlikely(skb_headroom(skb) < cs->hdr_len &&
-                     pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC)))
+        if (unlikely(skb_headroom(skb) < iv_len &&
+                     pskb_expand_head(skb, iv_len, 0, GFP_ATOMIC)))
                 return TX_DROP;
 
         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 
-        pos = skb_push(skb, cs->hdr_len);
-        memmove(pos, pos + cs->hdr_len, hdrlen);
+        pos = skb_push(skb, iv_len);
+        memmove(pos, pos + iv_len, hdrlen);
 
         return TX_CONTINUE;
 }
@@ -1217,7 +1216,7 @@ ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
                 if (!info->control.hw_key)
                         return TX_DROP;
 
-                if (tx->key->sta->cipher_scheme) {
+                if (tx->key->flags & KEY_FLAG_CIPHER_SCHEME) {
                         res = ieee80211_crypto_cs_encrypt(tx, skb);
                         if (res != TX_CONTINUE)
                                 return res;