From: Johannes Berg <johannes.berg@xxxxxxxxx>
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@xxxxxxxxx>
---
net/mac80211/rx.c | 6 ++----
net/mac80211/wep.c | 11 ++++++++---
net/mac80211/wpa.c | 22 +++++++++++++++++++++-
3 files changed, 31 insertions(+), 8 deletions(-)
--- a/net/mac80211/rx.c 2012-03-12 13:22:57.000000000 +0100
+++ b/net/mac80211/rx.c 2012-03-12 13:24:05.000000000 +0100
@@ -1063,10 +1063,6 @@ ieee80211_rx_h_decrypt(struct ieee80211_
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_
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;
--- a/net/mac80211/wep.c 2012-03-12 13:22:57.000000000 +0100
+++ b/net/mac80211/wep.c 2012-03-12 13:45:23.000000000 +0100
@@ -284,22 +284,27 @@ ieee80211_crypto_wep_decrypt(struct ieee
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;
--- a/net/mac80211/wpa.c 2012-03-10 09:17:06.000000000 +0100
+++ b/net/mac80211/wpa.c 2012-03-12 13:45:50.000000000 +0100
@@ -138,6 +138,10 @@ ieee80211_rx_h_michael_mic_verify(struct
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 iee
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 iee
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 iee
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
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;
--
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