mac80211: fix action frame length checks

The action frame length checks are one too small, there's not just
an action code as the comment makes you believe, there's a category
code too, and the category code is required in each action frame
(hence part of IEEE80211_MIN_ACTION_SIZE).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 11 insertions, 2 deletions

diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index eeb0ce2d5d37..59fd7fe377e0 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -581,6 +581,10 @@ void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
         size_t baselen;
         u32 last_hop_metric;
 
+        /* need action_code */
+        if (len < IEEE80211_MIN_ACTION_SIZE + 1)
+                return;
+
         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
                         len - baselen, &elems);
diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 7714b0e6e4d7..74983cfa7293 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -421,6 +421,10 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
         DECLARE_MAC_BUF(mac);
 #endif
 
+        /* need action_code, aux */
+        if (len < IEEE80211_MIN_ACTION_SIZE + 3)
+                return;
+
         if (is_multicast_ether_addr(mgmt->da)) {
                 mpl_dbg("Mesh plink: ignore frame from multicast address");
                 return;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index ae97d7e9945d..eb1832aa1fe5 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -60,7 +60,7 @@
 
 #define ERP_INFO_USE_PROTECTION BIT(1)
 
-/* mgmt header + 1 byte action code */
+/* mgmt header + 1 byte category code */
 #define IEEE80211_MIN_ACTION_SIZE (24 + 1)
 
 #define IEEE80211_ADDBA_PARAM_POLICY_MASK 0x0002
@@ -2988,7 +2988,8 @@ static void ieee80211_rx_mgmt_action(struct ieee80211_sub_if_data *sdata,
 {
         struct ieee80211_local *local = sdata->local;
 
-        if (len < IEEE80211_MIN_ACTION_SIZE)
+        /* all categories we currently handle have action_code */
+        if (len < IEEE80211_MIN_ACTION_SIZE + 1)
                 return;
 
         switch (mgmt->u.action.category) {