mac80211: verify that skb data is present
commit 9b395bc3be1cebf0144a127c7e67d56dbdac0930 upstream.
A number of places in the mesh code don't check that
the frame data is present and in the skb header when
trying to access. Add those checks and the necessary
pskb_may_pull() calls. This prevents accessing data
that doesn't actually exist.
To do this, export ieee80211_get_mesh_hdrlen() to be
able to use it in mac80211.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 06025a9..efe1b98 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -513,6 +513,11 @@
if (ieee80211_is_action(hdr->frame_control)) {
u8 category;
+
+ /* make sure category field is present */
+ if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE)
+ return RX_DROP_MONITOR;
+
mgmt = (struct ieee80211_mgmt *)hdr;
category = mgmt->u.action.category;
if (category != WLAN_CATEGORY_MESH_ACTION &&
@@ -1895,6 +1900,20 @@
hdr = (struct ieee80211_hdr *) skb->data;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
+
+ /* make sure fixed part of mesh header is there, also checks skb len */
+ if (!pskb_may_pull(rx->skb, hdrlen + 6))
+ return RX_DROP_MONITOR;
+
+ mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
+
+ /* make sure full mesh header is there, also checks skb len */
+ if (!pskb_may_pull(rx->skb,
+ hdrlen + ieee80211_get_mesh_hdrlen(mesh_hdr)))
+ return RX_DROP_MONITOR;
+
+ /* reload pointers */
+ hdr = (struct ieee80211_hdr *) skb->data;
mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
/* frame is in RMC, don't forward */
@@ -1918,9 +1937,12 @@
if (is_multicast_ether_addr(hdr->addr1)) {
mpp_addr = hdr->addr3;
proxied_addr = mesh_hdr->eaddr1;
- } else {
+ } else if (mesh_hdr->flags & MESH_FLAGS_AE_A5_A6) {
+ /* has_a4 already checked in ieee80211_rx_mesh_check */
mpp_addr = hdr->addr4;
proxied_addr = mesh_hdr->eaddr2;
+ } else {
+ return RX_DROP_MONITOR;
}
rcu_read_lock();
@@ -2362,6 +2384,10 @@
}
break;
case WLAN_CATEGORY_SELF_PROTECTED:
+ if (len < (IEEE80211_MIN_ACTION_SIZE +
+ sizeof(mgmt->u.action.u.self_prot.action_code)))
+ break;
+
switch (mgmt->u.action.u.self_prot.action_code) {
case WLAN_SP_MESH_PEERING_OPEN:
case WLAN_SP_MESH_PEERING_CLOSE:
@@ -2380,6 +2406,10 @@
}
break;
case WLAN_CATEGORY_MESH_ACTION:
+ if (len < (IEEE80211_MIN_ACTION_SIZE +
+ sizeof(mgmt->u.action.u.mesh_action.action_code)))
+ break;
+
if (!ieee80211_vif_is_mesh(&sdata->vif))
break;
if (mesh_action_is_path_sel(mgmt) &&
diff --git a/net/wireless/util.c b/net/wireless/util.c
index d39a6c2..d22dce7 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -290,7 +290,7 @@
}
EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
-static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
+unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
{
int ae = meshhdr->flags & MESH_FLAGS_AE;
/* 802.11-2012, 8.2.4.7.3 */
@@ -304,6 +304,7 @@
return 18;
}
}
+EXPORT_SYMBOL(ieee80211_get_mesh_hdrlen);
int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
enum nl80211_iftype iftype)