From a8286911881948c7a2ecc63ee4224c258cce2da3 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 12 Mar 2012 13:49:14 +0100 Subject: [PATCH] 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 Signed-off-by: John W. Linville --- net/mac80211/rx.c | 6 ++---- net/mac80211/wep.c | 11 ++++++++--- net/mac80211/wpa.c | 22 +++++++++++++++++++++- 3 files changed, 31 insertions(+), 8 deletions(-) diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index b38da13e2a88..53c88d145472 100644 --- 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 5cd87ba11bb7..7aa31bbfaa3b 100644 --- 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 b758350919ff..0ae23c60968c 100644 --- 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;