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    Subject[PATCH 012/241] mac80211: check management frame header length
    Date
    3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Johannes Berg <johannes.berg@intel.com>

    commit 4a4f1a5808c8bb0b72a4f6e5904c53fb8c9cd966 upstream.

    Due to pskb_may_pull() checking the skb length, all
    non-management frames are checked on input whether
    their 802.11 header is fully present. Also add that
    check for management frames and remove a check that
    is now duplicate. This prevents accessing skb data
    beyond the frame end.

    Signed-off-by: Johannes Berg <johannes.berg@intel.com>
    [ herton: unfuzz patch ]
    Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
    ---
    net/mac80211/rx.c | 12 ++++++++----
    1 file changed, 8 insertions(+), 4 deletions(-)

    diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
    index 4e4fc93..38800d3 100644
    --- a/net/mac80211/rx.c
    +++ b/net/mac80211/rx.c
    @@ -1473,7 +1473,6 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
    frag = sc & IEEE80211_SCTL_FRAG;

    if (likely((!ieee80211_has_morefrags(fc) && frag == 0) ||
    - (rx->skb)->len < 24 ||
    is_multicast_ether_addr(hdr->addr1))) {
    /* not fragmented */
    goto out;
    @@ -2923,10 +2922,15 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
    test_bit(SCAN_SW_SCANNING, &local->scanning)))
    status->rx_flags |= IEEE80211_RX_IN_SCAN;

    - if (ieee80211_is_mgmt(fc))
    - err = skb_linearize(skb);
    - else
    + if (ieee80211_is_mgmt(fc)) {
    + /* drop frame if too short for header */
    + if (skb->len < ieee80211_hdrlen(fc))
    + err = -ENOBUFS;
    + else
    + err = skb_linearize(skb);
    + } else {
    err = !pskb_may_pull(skb, ieee80211_hdrlen(fc));
    + }

    if (err) {
    dev_kfree_skb(skb);
    --
    1.7.9.5


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