batman-adv: Fix invalid read while copying bat_iv.bcast_own

batadv_iv_ogm_orig_del_if removes a part of the bcast_own which previously
belonged to the now removed interface. This is done by copying all data
which comes before the removed interface and then appending all the data
which comes after the removed interface.

The address calculation for the position of the data which comes after the
removed interface assumed that the bat_iv.bcast_own is a pointer to a
single byte datatype. But it is a pointer to unsigned long and thus the
calculated position was wrong off factor sizeof(unsigned long).

Fixes: 83a8342678a0 ("more basic routing code added (forwarding packets /
bitarray added)")

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 912d9c36fb1c9e63d1358bd044f5a0218f2f4d77..aa94b4ec766aa34e3676693b601a476e95c3f4fd 100644 (file)
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -185,7 +185,8 @@ unlock:
 static int batadv_iv_ogm_orig_del_if(struct batadv_orig_node *orig_node,
                                     int max_if_num, int del_if_num)
 {
-       int chunk_size,  ret = -ENOMEM, if_offset;
+       int ret = -ENOMEM;
+       size_t chunk_size, if_offset;
        void *data_ptr = NULL;
 
        spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);
@@ -203,8 +204,9 @@ static int batadv_iv_ogm_orig_del_if(struct batadv_orig_node *orig_node,
        memcpy(data_ptr, orig_node->bat_iv.bcast_own, del_if_num * chunk_size);
 
        /* copy second part */
+       if_offset = (del_if_num + 1) * chunk_size;
        memcpy((char *)data_ptr + del_if_num * chunk_size,
-              orig_node->bat_iv.bcast_own + ((del_if_num + 1) * chunk_size),
+              (uint8_t *)orig_node->bat_iv.bcast_own + if_offset,
               (max_if_num - del_if_num) * chunk_size);
 
 free_bcast_own: