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FAILED: patch "[PATCH] mac80211: mesh: embedd mesh_paths and mpp_paths into" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Jan 7, 2022

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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8b5cb7e41d9d77ffca036b0239177de123394a55 Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <[email protected]>
Date: Thu, 30 Dec 2021 22:55:47 +0300
Subject: [PATCH] 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 [email protected]
Signed-off-by Pavel Skripkin <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Johannes Berg <[email protected]>
net/mac80211/ieee80211_i.h +22 -2
index 5666bbb8860b..482c98ede19b 100644
@@ -647,6 +647,26 @@ struct mesh_csa_settings {
 	struct cfg80211_csa_settings settings;
 };
 
+/**
+ * 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 */
+};
+
 struct ieee80211_if_mesh {
 	struct timer_list housekeeping_timer;
 	struct timer_list mesh_path_timer;

@@ -721,8 +741,8 @@ struct ieee80211_if_mesh {
 	/* offset from skb->data while building IE */
 	int meshconf_offset;
 
-	struct mesh_table *mesh_paths;
-	struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
+	struct mesh_table mesh_paths;
+	struct mesh_table mpp_paths; /* Store paths for MPP&MAP */
 	int mesh_paths_generation;
 	int mpp_paths_generation;
 };
net/mac80211/mesh.h +1 -21
index 77080b4f87b8..b2b717a78114 100644
@@ -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);
net/mac80211/mesh_pathtbl.c +31 -58

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