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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
---
Happy New Year and Merry Christmas! :)
With regards,
Pavel Skripkin
---
net/mac80211/ieee80211_i.h | 24 +++++++++-
net/mac80211/mesh.h | 22 +--------
net/mac80211/mesh_pathtbl.c | 89 +++++++++++++------------------------
3 files changed, 54 insertions(+), 81 deletions(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 5666bbb8860b..482c98ede19b 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -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;
};
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);
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index 7cab1cf09bf1..acc1c299f1ae 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -47,32 +47,24 @@ static void mesh_path_rht_free(void *ptr, void *tblptr)
mesh_path_free_rcu(tbl, mpath);
}
-static struct mesh_table *mesh_table_alloc(void)
+static void mesh_table_init(struct mesh_table *tbl)
{
- struct mesh_table *newtbl;
+ INIT_HLIST_HEAD(&tbl->known_gates);
+ INIT_HLIST_HEAD(&tbl->walk_head);
+ atomic_set(&tbl->entries, 0);
+ spin_lock_init(&tbl->gates_lock);
+ spin_lock_init(&tbl->walk_lock);
- newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
- if (!newtbl)
- return NULL;
-
- INIT_HLIST_HEAD(&newtbl->known_gates);
- INIT_HLIST_HEAD(&newtbl->walk_head);
- atomic_set(&newtbl->entries, 0);
- spin_lock_init(&newtbl->gates_lock);
- spin_lock_init(&newtbl->walk_lock);
- if (rhashtable_init(&newtbl->rhead, &mesh_rht_params)) {
- kfree(newtbl);
- return NULL;
- }
-
- return newtbl;
+ /* rhashtable_init() may fail only in case of wrong
+ * mesh_rht_params
+ */
+ WARN_ON(rhashtable_init(&tbl->rhead, &mesh_rht_params));
}
static void mesh_table_free(struct mesh_table *tbl)
{
rhashtable_free_and_destroy(&tbl->rhead,
mesh_path_rht_free, tbl);
- kfree(tbl);
}
/**
@@ -238,13 +230,13 @@ static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
struct mesh_path *
mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
{
- return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
+ return mpath_lookup(&sdata->u.mesh.mesh_paths, dst, sdata);
}
struct mesh_path *
mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
{
- return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
+ return mpath_lookup(&sdata->u.mesh.mpp_paths, dst, sdata);
}
static struct mesh_path *
@@ -281,7 +273,7 @@ __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
struct mesh_path *
mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
{
- return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
+ return __mesh_path_lookup_by_idx(&sdata->u.mesh.mesh_paths, idx);
}
/**
@@ -296,7 +288,7 @@ mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
struct mesh_path *
mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
{
- return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
+ return __mesh_path_lookup_by_idx(&sdata->u.mesh.mpp_paths, idx);
}
/**
@@ -309,7 +301,7 @@ int mesh_path_add_gate(struct mesh_path *mpath)
int err;
rcu_read_lock();
- tbl = mpath->sdata->u.mesh.mesh_paths;
+ tbl = &mpath->sdata->u.mesh.mesh_paths;
spin_lock_bh(&mpath->state_lock);
if (mpath->is_gate) {
@@ -418,7 +410,7 @@ struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
if (!new_mpath)
return ERR_PTR(-ENOMEM);
- tbl = sdata->u.mesh.mesh_paths;
+ tbl = &sdata->u.mesh.mesh_paths;
spin_lock_bh(&tbl->walk_lock);
mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
&new_mpath->rhash,
@@ -460,7 +452,7 @@ int mpp_path_add(struct ieee80211_sub_if_data *sdata,
return -ENOMEM;
memcpy(new_mpath->mpp, mpp, ETH_ALEN);
- tbl = sdata->u.mesh.mpp_paths;
+ tbl = &sdata->u.mesh.mpp_paths;
spin_lock_bh(&tbl->walk_lock);
ret = rhashtable_lookup_insert_fast(&tbl->rhead,
@@ -489,7 +481,7 @@ int mpp_path_add(struct ieee80211_sub_if_data *sdata,
void mesh_plink_broken(struct sta_info *sta)
{
struct ieee80211_sub_if_data *sdata = sta->sdata;
- struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
+ struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
struct mesh_path *mpath;
@@ -548,7 +540,7 @@ static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
void mesh_path_flush_by_nexthop(struct sta_info *sta)
{
struct ieee80211_sub_if_data *sdata = sta->sdata;
- struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
+ struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
struct mesh_path *mpath;
struct hlist_node *n;
@@ -563,7 +555,7 @@ void mesh_path_flush_by_nexthop(struct sta_info *sta)
static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
const u8 *proxy)
{
- struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
+ struct mesh_table *tbl = &sdata->u.mesh.mpp_paths;
struct mesh_path *mpath;
struct hlist_node *n;
@@ -597,8 +589,8 @@ static void table_flush_by_iface(struct mesh_table *tbl)
*/
void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
{
- table_flush_by_iface(sdata->u.mesh.mesh_paths);
- table_flush_by_iface(sdata->u.mesh.mpp_paths);
+ table_flush_by_iface(&sdata->u.mesh.mesh_paths);
+ table_flush_by_iface(&sdata->u.mesh.mpp_paths);
}
/**
@@ -644,7 +636,7 @@ int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
/* flush relevant mpp entries first */
mpp_flush_by_proxy(sdata, addr);
- err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
+ err = table_path_del(&sdata->u.mesh.mesh_paths, sdata, addr);
sdata->u.mesh.mesh_paths_generation++;
return err;
}
@@ -682,7 +674,7 @@ int mesh_path_send_to_gates(struct mesh_path *mpath)
struct mesh_path *gate;
bool copy = false;
- tbl = sdata->u.mesh.mesh_paths;
+ tbl = &sdata->u.mesh.mesh_paths;
rcu_read_lock();
hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
@@ -762,29 +754,10 @@ void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
mesh_path_tx_pending(mpath);
}
-int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
+void mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
{
- struct mesh_table *tbl_path, *tbl_mpp;
- int ret;
-
- tbl_path = mesh_table_alloc();
- if (!tbl_path)
- return -ENOMEM;
-
- tbl_mpp = mesh_table_alloc();
- if (!tbl_mpp) {
- ret = -ENOMEM;
- goto free_path;
- }
-
- sdata->u.mesh.mesh_paths = tbl_path;
- sdata->u.mesh.mpp_paths = tbl_mpp;
-
- return 0;
-
-free_path:
- mesh_table_free(tbl_path);
- return ret;
+ mesh_table_init(&sdata->u.mesh.mesh_paths);
+ mesh_table_init(&sdata->u.mesh.mpp_paths);
}
static
@@ -806,12 +779,12 @@ void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
{
- mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
- mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
+ mesh_path_tbl_expire(sdata, &sdata->u.mesh.mesh_paths);
+ mesh_path_tbl_expire(sdata, &sdata->u.mesh.mpp_paths);
}
void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
{
- mesh_table_free(sdata->u.mesh.mesh_paths);
- mesh_table_free(sdata->u.mesh.mpp_paths);
+ mesh_table_free(&sdata->u.mesh.mesh_paths);
+ mesh_table_free(&sdata->u.mesh.mpp_paths);
}
--
2.34.1
