From: Johannes Berg Date: Tue, 18 Dec 2007 14:11:35 +0000 (+0100) Subject: mac80211: warn when receiving frames with unaligned data X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=81100eb80add328c4d2a377326f15aa0e7236398;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git mac80211: warn when receiving frames with unaligned data This patch makes mac80211 warn (once) when the driver passes up a frame in which the payload data is not aligned on a four-byte boundary, with a long comment for people who run into the condition and need to know what to do. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 00f908d9275..a7263fc476b 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1443,6 +1443,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, struct ieee80211_sub_if_data *prev = NULL; struct sk_buff *skb_new; u8 *bssid; + int hdrlen; /* * key references and virtual interfaces are protected using RCU @@ -1472,6 +1473,18 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, rx.fc = le16_to_cpu(hdr->frame_control); type = rx.fc & IEEE80211_FCTL_FTYPE; + /* + * Drivers are required to align the payload data to a four-byte + * boundary, so the last two bits of the address where it starts + * may not be set. The header is required to be directly before + * the payload data, padding like atheros hardware adds which is + * inbetween the 802.11 header and the payload is not supported, + * the driver is required to move the 802.11 header further back + * in that case. + */ + hdrlen = ieee80211_get_hdrlen(rx.fc); + WARN_ON_ONCE(((unsigned long)(skb->data + hdrlen)) & 3); + if (type == IEEE80211_FTYPE_DATA || type == IEEE80211_FTYPE_MGMT) local->dot11ReceivedFragmentCount++;