mac80211: mesh: embedd mesh_paths and mpp_paths into ieee80211_if_mesh

Syzbot hit NULL deref in rhashtable_free_and_destroy(). The problem was
in mesh_paths and mpp_paths being NULL.

mesh_pathtbl_init() could fail in case of memory allocation failure, but
nobody cared, since ieee80211_mesh_init_sdata() returns void. It led to
leaving 2 pointers as NULL. Syzbot has found null deref on exit path,
but it could happen anywhere else, because code assumes these pointers are
valid.

Since all ieee80211_*_setup_sdata functions are void and do not fail,
let's embedd mesh_paths and mpp_paths into parent struct to avoid
adding error handling on higher levels and follow the pattern of others
setup_sdata functions

Fixes: 60854fd94573 ("mac80211: mesh: convert path table to rhashtable")
Reported-and-tested-by: syzbot+860268315ba86ea6b96b@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Link: https://lore.kernel.org/r/20211230195547.23977-1-paskripkin@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 1 insertions, 21 deletions

diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
index 77080b4f87b8..b2b717a78114 100644
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -127,26 +127,6 @@ struct mesh_path {
 	u32 path_change_count;
 };
 
-/**
- * struct mesh_table
- *
- * @known_gates: list of known mesh gates and their mpaths by the station. The
- * gate's mpath may or may not be resolved and active.
- * @gates_lock: protects updates to known_gates
- * @rhead: the rhashtable containing struct mesh_paths, keyed by dest addr
- * @walk_head: linked list containing all mesh_path objects
- * @walk_lock: lock protecting walk_head
- * @entries: number of entries in the table
- */
-struct mesh_table {
-	struct hlist_head known_gates;
-	spinlock_t gates_lock;
-	struct rhashtable rhead;
-	struct hlist_head walk_head;
-	spinlock_t walk_lock;
-	atomic_t entries;		/* Up to MAX_MESH_NEIGHBOURS */
-};
-
 /* Recent multicast cache */
 /* RMC_BUCKETS must be a power of 2, maximum 256 */
 #define RMC_BUCKETS		256
@@ -308,7 +288,7 @@ int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta);
 void mesh_path_flush_pending(struct mesh_path *mpath);
 void mesh_path_tx_pending(struct mesh_path *mpath);
-int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata);
+void mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata);
 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata);
 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr);
 void mesh_path_timer(struct timer_list *t);