Commit 62bf1d76 authored by Harvey Harrison's avatar Harvey Harrison Committed by John W. Linville
Browse files

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: default avatarHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 798ee985

net/mac80211/main.c

+11 −14
Original line number Diff line number Diff line
@@ -1244,9 +1244,10 @@ 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_hdr *hdr = (struct ieee80211_hdr *)skb->data;



	hdrlen = ieee80211_get_hdrlen_from_skb(skb);

	hdrlen = ieee80211_hdrlen(hdr->frame_control);



	if (!key)

		goto no_key;
@@ -1268,24 +1269,20 @@ 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);

	}

}

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