mac80211: linearize SKBs as needed for crypto

Not linearizing every SKB will help actually pass
non-linear SKBs all the way up when on an encrypted
connection. For now, linearize TKIP completely as
it is lower performance and I don't quite grok all
the details.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b38da13..53c88d1 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1063,10 +1063,6 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
                return RX_DROP_MONITOR;
        }
 
-       if (skb_linearize(rx->skb))
-               return RX_DROP_UNUSABLE;
-       /* the hdr variable is invalid now! */
-
        switch (rx->key->conf.cipher) {
        case WLAN_CIPHER_SUITE_WEP40:
        case WLAN_CIPHER_SUITE_WEP104:
@@ -1089,6 +1085,8 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
                return RX_DROP_UNUSABLE;
        }
 
+       /* the hdr variable is invalid after the decrypt handlers */
+
        /* either the frame has been decrypted or will be dropped */
        status->flag |= RX_FLAG_DECRYPTED;
 

diff --git a/net/mac80211/wep.c b/net/mac80211/wep.c
index 5cd87ba..7aa31bb 100644 (file)
--- a/net/mac80211/wep.c
+++ b/net/mac80211/wep.c
@@ -284,22 +284,27 @@ ieee80211_crypto_wep_decrypt(struct ieee80211_rx_data *rx)
        struct sk_buff *skb = rx->skb;
        struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+       __le16 fc = hdr->frame_control;
 
-       if (!ieee80211_is_data(hdr->frame_control) &&
-           !ieee80211_is_auth(hdr->frame_control))
+       if (!ieee80211_is_data(fc) && !ieee80211_is_auth(fc))
                return RX_CONTINUE;
 
        if (!(status->flag & RX_FLAG_DECRYPTED)) {
+               if (skb_linearize(rx->skb))
+                       return RX_DROP_UNUSABLE;
                if (rx->sta && ieee80211_wep_is_weak_iv(rx->skb, rx->key))
                        rx->sta->wep_weak_iv_count++;
                if (ieee80211_wep_decrypt(rx->local, rx->skb, rx->key))
                        return RX_DROP_UNUSABLE;
        } else if (!(status->flag & RX_FLAG_IV_STRIPPED)) {
+               if (!pskb_may_pull(rx->skb, ieee80211_hdrlen(fc) + WEP_IV_LEN))
+                       return RX_DROP_UNUSABLE;
                if (rx->sta && ieee80211_wep_is_weak_iv(rx->skb, rx->key))
                        rx->sta->wep_weak_iv_count++;
                ieee80211_wep_remove_iv(rx->local, rx->skb, rx->key);
                /* remove ICV */
-               skb_trim(rx->skb, rx->skb->len - WEP_ICV_LEN);
+               if (pskb_trim(rx->skb, rx->skb->len - WEP_ICV_LEN))
+                       return RX_DROP_UNUSABLE;
        }
 
        return RX_CONTINUE;

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index b758350..0ae23c6 100644 (file)
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -138,6 +138,10 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
        if (skb->len < hdrlen + MICHAEL_MIC_LEN)
                return RX_DROP_UNUSABLE;
 
+       if (skb_linearize(rx->skb))
+               return RX_DROP_UNUSABLE;
+       hdr = (void *)skb->data;
+
        data = skb->data + hdrlen;
        data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
        key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
@@ -253,6 +257,11 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
        if (!rx->sta || skb->len - hdrlen < 12)
                return RX_DROP_UNUSABLE;
 
+       /* it may be possible to optimize this a bit more */
+       if (skb_linearize(rx->skb))
+               return RX_DROP_UNUSABLE;
+       hdr = (void *)skb->data;
+
        /*
         * Let TKIP code verify IV, but skip decryption.
         * In the case where hardware checks the IV as well,
@@ -484,6 +493,14 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
        if (!rx->sta || data_len < 0)
                return RX_DROP_UNUSABLE;
 
+       if (status->flag & RX_FLAG_DECRYPTED) {
+               if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN))
+                       return RX_DROP_UNUSABLE;
+       } else {
+               if (skb_linearize(rx->skb))
+                       return RX_DROP_UNUSABLE;
+       }
+
        ccmp_hdr2pn(pn, skb->data + hdrlen);
 
        queue = rx->security_idx;
@@ -509,7 +526,8 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
        memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
 
        /* Remove CCMP header and MIC */
-       skb_trim(skb, skb->len - CCMP_MIC_LEN);
+       if (pskb_trim(skb, skb->len - CCMP_MIC_LEN))
+               return RX_DROP_UNUSABLE;
        memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
        skb_pull(skb, CCMP_HDR_LEN);
 
@@ -609,6 +627,8 @@ ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
        if (!ieee80211_is_mgmt(hdr->frame_control))
                return RX_CONTINUE;
 
+       /* management frames are already linear */
+
        if (skb->len < 24 + sizeof(*mmie))
                return RX_DROP_UNUSABLE;