3 files changed, 54 insertions, 11 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 1a8f50af49a0..ecaae10426f9 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1822,7 +1822,10 @@ void ieee80211_restart_hw(struct ieee80211_hw *hw);
  * ieee80211_rx - receive frame
  *
  * Use this function to hand received frames to mac80211. The receive
- * buffer in @skb must start with an IEEE 802.11 header.
+ * buffer in @skb must start with an IEEE 802.11 header. In case of a
+ * paged @skb is used, the driver is recommended to put the ieee80211
+ * header of the frame on the linear part of the @skb to avoid memory
+ * allocation and/or memcpy by the stack.
  *
  * This function may not be called in IRQ context. Calls to this function
  * for a single hardware must be synchronized against each other. Calls to
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 1da57c8e849a..11ed5aa90f83 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -38,7 +38,7 @@ static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
 {
         if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
                 if (likely(skb->len > FCS_LEN))
-                        skb_trim(skb, skb->len - FCS_LEN);
+                        __pskb_trim(skb, skb->len - FCS_LEN);
                 else {
                         /* driver bug */
                         WARN_ON(1);
@@ -227,6 +227,12 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
         if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
                 present_fcs_len = FCS_LEN;
 
+        /* make sure hdr->frame_control is on the linear part */
+        if (!pskb_may_pull(origskb, 2)) {
+                dev_kfree_skb(origskb);
+                return NULL;
+        }
+
         if (!local->monitors) {
                 if (should_drop_frame(origskb, present_fcs_len)) {
                         dev_kfree_skb(origskb);
@@ -931,6 +937,9 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
                 return RX_DROP_MONITOR;
         }
 
+        if (skb_linearize(rx->skb))
+                return RX_DROP_UNUSABLE;
+
         /* Check for weak IVs if possible */
         if (rx->sta && rx->key->conf.alg == ALG_WEP &&
             ieee80211_is_data(hdr->frame_control) &&
@@ -1231,6 +1240,9 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
         }
         I802_DEBUG_INC(rx->local->rx_handlers_fragments);
 
+        if (skb_linearize(rx->skb))
+                return RX_DROP_UNUSABLE;
+
         seq = (sc & IEEE80211_SCTL_SEQ) >> 4;
 
         if (frag == 0) {
@@ -1588,6 +1600,9 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
         skb->dev = dev;
         __skb_queue_head_init(&frame_list);
 
+        if (skb_linearize(skb))
+                return RX_DROP_UNUSABLE;
+
         ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
                                  rx->sdata->vif.type,
                                  rx->local->hw.extra_tx_headroom);
@@ -2357,29 +2372,42 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
         struct ieee80211_local *local = hw_to_local(hw);
         struct ieee80211_sub_if_data *sdata;
         struct ieee80211_hdr *hdr;
+        __le16 fc;
         struct ieee80211_rx_data rx;
         int prepares;
         struct ieee80211_sub_if_data *prev = NULL;
         struct sk_buff *skb_new;
         struct sta_info *sta, *tmp;
         bool found_sta = false;
+        int err = 0;
 
-        hdr = (struct ieee80211_hdr *)skb->data;
+        fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
         memset(&rx, 0, sizeof(rx));
         rx.skb = skb;
         rx.local = local;
 
-        if (ieee80211_is_data(hdr->frame_control) || ieee80211_is_mgmt(hdr->frame_control))
+        if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))
                 local->dot11ReceivedFragmentCount++;
 
         if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
                      test_bit(SCAN_OFF_CHANNEL, &local->scanning)))
                 rx.flags |= IEEE80211_RX_IN_SCAN;
 
+        if (ieee80211_is_mgmt(fc))
+                err = skb_linearize(skb);
+        else
+                err = !pskb_may_pull(skb, ieee80211_hdrlen(fc));
+
+        if (err) {
+                dev_kfree_skb(skb);
+                return;
+        }
+
+        hdr = (struct ieee80211_hdr *)skb->data;
         ieee80211_parse_qos(&rx);
         ieee80211_verify_alignment(&rx);
 
-        if (ieee80211_is_data(hdr->frame_control)) {
+        if (ieee80211_is_data(fc)) {
                 for_each_sta_info(local, hdr->addr2, sta, tmp) {
                         rx.sta = sta;
                         found_sta = true;
diff --git a/net/wireless/util.c b/net/wireless/util.c
index be2ab8c59e3a..7acb81b9675d 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -330,11 +330,18 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
                 if (iftype == NL80211_IFTYPE_MESH_POINT) {
                         struct ieee80211s_hdr *meshdr =
                                 (struct ieee80211s_hdr *) (skb->data + hdrlen);
-                        hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
+                        /* make sure meshdr->flags is on the linear part */
+                        if (!pskb_may_pull(skb, hdrlen + 1))
+                                return -1;
                         if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
-                                memcpy(dst, meshdr->eaddr1, ETH_ALEN);
-                                memcpy(src, meshdr->eaddr2, ETH_ALEN);
+                                skb_copy_bits(skb, hdrlen +
+                                        offsetof(struct ieee80211s_hdr, eaddr1),
+                                        dst, ETH_ALEN);
+                                skb_copy_bits(skb, hdrlen +
+                                        offsetof(struct ieee80211s_hdr, eaddr2),
+                                        src, ETH_ALEN);
                         }
+                        hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
                 }
                 break;
         case cpu_to_le16(IEEE80211_FCTL_FROMDS):
@@ -346,9 +353,14 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
                 if (iftype == NL80211_IFTYPE_MESH_POINT) {
                         struct ieee80211s_hdr *meshdr =
                                 (struct ieee80211s_hdr *) (skb->data + hdrlen);
-                        hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
+                        /* make sure meshdr->flags is on the linear part */
+                        if (!pskb_may_pull(skb, hdrlen + 1))
+                                return -1;
                         if (meshdr->flags & MESH_FLAGS_AE_A4)
-                                memcpy(src, meshdr->eaddr1, ETH_ALEN);
+                                skb_copy_bits(skb, hdrlen +
+                                        offsetof(struct ieee80211s_hdr, eaddr1),
+                                        src, ETH_ALEN);
+                        hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
                 }
                 break;
         case cpu_to_le16(0):
@@ -357,7 +369,7 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
                 break;
         }
 
-        if (unlikely(skb->len - hdrlen < 8))
+        if (!pskb_may_pull(skb, hdrlen + 8))
                 return -1;
 
         payload = skb->data + hdrlen;