2008-07-09 19:44:37

by Harvey Harrison

[permalink] [raw]
Subject: [PATCH 4/4] mac80211: explicitly check skb->len

ieee80211_get_hdrlen_from_skb internally checks the skb is long enough to
hold the full ieee80211_hdr, else it returns zero. Use ieee80211_hdrlen
which always returns the hdrlen and check the remaining room in the
skb explicitly when removing encryption headers or the qos control field.

Signed-off-by: Harvey Harrison <[email protected]>
---
net/mac80211/main.c | 26 +++++++++++---------------
1 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index cf477ad..c247ecc 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1274,16 +1274,16 @@ static void ieee80211_remove_tx_extra(struct ieee80211_local *local,
struct ieee80211_key *key,
struct sk_buff *skb)
{
- int hdrlen, iv_len, mic_len;
+ unsigned int hdrlen, iv_len, mic_len;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;

+ hdrlen = ieee80211_hdrlen(hdr->frame_control);
info->flags &= IEEE80211_TX_CTL_REQ_TX_STATUS |
IEEE80211_TX_CTL_DO_NOT_ENCRYPT |
IEEE80211_TX_CTL_REQUEUE |
IEEE80211_TX_CTL_EAPOL_FRAME;

- hdrlen = ieee80211_get_hdrlen_from_skb(skb);
-
if (!key)
goto no_key;

@@ -1304,24 +1304,20 @@ static void ieee80211_remove_tx_extra(struct ieee80211_local *local,
goto no_key;
}

- if (skb->len >= mic_len &&
+ if (skb->len >= hdrlen + mic_len &&
!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
skb_trim(skb, skb->len - mic_len);
- if (skb->len >= iv_len && skb->len > hdrlen) {
+ if (skb->len >= hdrlen + iv_len) {
memmove(skb->data + iv_len, skb->data, hdrlen);
- skb_pull(skb, iv_len);
+ hdr = (struct ieee80211_hdr *)skb_pull(skb, iv_len);
}

no_key:
- {
- struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
- u16 fc = le16_to_cpu(hdr->frame_control);
- if ((fc & 0x8C) == 0x88) /* QoS Control Field */ {
- fc &= ~IEEE80211_STYPE_QOS_DATA;
- hdr->frame_control = cpu_to_le16(fc);
- memmove(skb->data + 2, skb->data, hdrlen - 2);
- skb_pull(skb, 2);
- }
+ if (ieee80211_is_data_qos(hdr->frame_control)) {
+ hdr->frame_control &= ~cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
+ memmove(skb->data + IEEE80211_QOS_CTL_LEN, skb->data,
+ hdrlen - IEEE80211_QOS_CTL_LEN);
+ skb_pull(skb, IEEE80211_QOS_CTL_LEN);
}
}

--
1.5.6.1.322.ge904b