Merge tag 'batadv-net-for-davem-20190830' of git://git.open-mesh.org/linux-merge

Simon Wunderlich says:

====================
Here are two batman-adv bugfixes:

 - Fix OGM and OGMv2 header read boundary check,
   by Sven Eckelmann (2 patches)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 25 insertions, 13 deletions

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 240ed70912d6..d78938e3e008 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -277,17 +277,23 @@ static u8 batadv_hop_penalty(u8 tq, const struct batadv_priv *bat_priv)
  * batadv_iv_ogm_aggr_packet() - checks if there is another OGM attached
  * @buff_pos: current position in the skb
  * @packet_len: total length of the skb
- * @tvlv_len: tvlv length of the previously considered OGM
+ * @ogm_packet: potential OGM in buffer
  *
  * Return: true if there is enough space for another OGM, false otherwise.
  */
-static bool batadv_iv_ogm_aggr_packet(int buff_pos, int packet_len,
-                                      __be16 tvlv_len)
+static bool
+batadv_iv_ogm_aggr_packet(int buff_pos, int packet_len,
+                          const struct batadv_ogm_packet *ogm_packet)
 {
         int next_buff_pos = 0;
 
-        next_buff_pos += buff_pos + BATADV_OGM_HLEN;
-        next_buff_pos += ntohs(tvlv_len);
+        /* check if there is enough space for the header */
+        next_buff_pos += buff_pos + sizeof(*ogm_packet);
+        if (next_buff_pos > packet_len)
+                return false;
+
+        /* check if there is enough space for the optional TVLV */
+        next_buff_pos += ntohs(ogm_packet->tvlv_len);
 
         return (next_buff_pos <= packet_len) &&
                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
@@ -315,7 +321,7 @@ static void batadv_iv_ogm_send_to_if(struct batadv_forw_packet *forw_packet,
 
         /* adjust all flags and log packets */
         while (batadv_iv_ogm_aggr_packet(buff_pos, forw_packet->packet_len,
-                                         batadv_ogm_packet->tvlv_len)) {
+                                         batadv_ogm_packet)) {
                 /* we might have aggregated direct link packets with an
                  * ordinary base packet
                  */
@@ -1704,7 +1710,7 @@ static int batadv_iv_ogm_receive(struct sk_buff *skb,
 
         /* unpack the aggregated packets and process them one by one */
         while (batadv_iv_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
-                                         ogm_packet->tvlv_len)) {
+                                         ogm_packet)) {
                 batadv_iv_ogm_process(skb, ogm_offset, if_incoming);
 
                 ogm_offset += BATADV_OGM_HLEN;
diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index fad95ef64e01..bc06e3cdfa84 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -631,17 +631,23 @@ batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
  * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated
  * @buff_pos: current position in the skb
  * @packet_len: total length of the skb
- * @tvlv_len: tvlv length of the previously considered OGM
+ * @ogm2_packet: potential OGM2 in buffer
  *
  * Return: true if there is enough space for another OGM, false otherwise.
  */
-static bool batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
-                                     __be16 tvlv_len)
+static bool
+batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
+                         const struct batadv_ogm2_packet *ogm2_packet)
 {
         int next_buff_pos = 0;
 
-        next_buff_pos += buff_pos + BATADV_OGM2_HLEN;
-        next_buff_pos += ntohs(tvlv_len);
+        /* check if there is enough space for the header */
+        next_buff_pos += buff_pos + sizeof(*ogm2_packet);
+        if (next_buff_pos > packet_len)
+                return false;
+
+        /* check if there is enough space for the optional TVLV */
+        next_buff_pos += ntohs(ogm2_packet->tvlv_len);
 
         return (next_buff_pos <= packet_len) &&
                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
@@ -818,7 +824,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,
         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 
         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
-                                        ogm_packet->tvlv_len)) {
+                                        ogm_packet)) {
                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 
                 ogm_offset += BATADV_OGM2_HLEN;