mac80211: verify that skb data is present
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.
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 99cdee1..265a032d 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -531,6 +531,11 @@
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 &&
@@ -1892,6 +1897,20 @@
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 */
@@ -1915,9 +1934,12 @@
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();
@@ -2354,6 +2376,10 @@
}
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:
@@ -2372,6 +2398,10 @@
}
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) &&