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Message-Id: <20211024131356.10699-1-paskripkin@gmail.com>
Date: Sun, 24 Oct 2021 16:13:56 +0300
From: Pavel Skripkin <paskripkin@...il.com>
To: mareklindner@...mailbox.ch, sw@...onwunderlich.de, a@...table.cc,
sven@...fation.org, davem@...emloft.net, kuba@...nel.org
Cc: b.a.t.m.a.n@...ts.open-mesh.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
Pavel Skripkin <paskripkin@...il.com>,
syzbot+28b0702ada0bf7381f58@...kaller.appspotmail.com
Subject: [PATCH] net: batman-adv: fix error handling
Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was
in wrong error handling in batadv_mesh_init().
Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case
of any batadv_*_init() calls failure. This approach may work well, when
there is some kind of indicator, which can tell which parts of batadv are
initialized; but there isn't any.
All written above lead to cleaning up uninitialized fields. Even if we hide
ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit
GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1]
To fix these bugs we can unwind batadv_*_init() calls one by one.
It is good approach for 2 reasons: 1) It fixes bugs on error handling
path 2) It improves the performance, since we won't call unneeded
batadv_*_free() functions.
So, this patch makes all batadv_*_init() clean up all allocated memory
before returning with an error to no call correspoing batadv_*_free()
and open-codes batadv_mesh_free() with proper order to avoid touching
uninitialized fields.
Link: https://lore.kernel.org/netdev/000000000000c87fbd05cef6bcb0@google.com/ [1]
Reported-and-tested-by: syzbot+28b0702ada0bf7381f58@...kaller.appspotmail.com
Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Signed-off-by: Pavel Skripkin <paskripkin@...il.com>
---
net/batman-adv/bridge_loop_avoidance.c | 8 +++-
net/batman-adv/main.c | 56 ++++++++++++++++++--------
net/batman-adv/network-coding.c | 4 +-
net/batman-adv/translation-table.c | 4 +-
4 files changed, 52 insertions(+), 20 deletions(-)
diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index 1669744304c5..17687848daec 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -1560,10 +1560,14 @@ int batadv_bla_init(struct batadv_priv *bat_priv)
return 0;
bat_priv->bla.claim_hash = batadv_hash_new(128);
- bat_priv->bla.backbone_hash = batadv_hash_new(32);
+ if (!bat_priv->bla.claim_hash)
+ return -ENOMEM;
- if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
+ bat_priv->bla.backbone_hash = batadv_hash_new(32);
+ if (!bat_priv->bla.backbone_hash) {
+ batadv_hash_destroy(bat_priv->bla.claim_hash);
return -ENOMEM;
+ }
batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
&batadv_claim_hash_lock_class_key);
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 3ddd66e4c29e..5207cd8d6ad8 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -190,29 +190,41 @@ int batadv_mesh_init(struct net_device *soft_iface)
bat_priv->gw.generation = 0;
- ret = batadv_v_mesh_init(bat_priv);
- if (ret < 0)
- goto err;
-
ret = batadv_originator_init(bat_priv);
- if (ret < 0)
- goto err;
+ if (ret < 0) {
+ atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+ goto err_orig;
+ }
ret = batadv_tt_init(bat_priv);
- if (ret < 0)
- goto err;
+ if (ret < 0) {
+ atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+ goto err_tt;
+ }
+
+ ret = batadv_v_mesh_init(bat_priv);
+ if (ret < 0) {
+ atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+ goto err_v;
+ }
ret = batadv_bla_init(bat_priv);
- if (ret < 0)
- goto err;
+ if (ret < 0) {
+ atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+ goto err_bla;
+ }
ret = batadv_dat_init(bat_priv);
- if (ret < 0)
- goto err;
+ if (ret < 0) {
+ atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+ goto err_dat;
+ }
ret = batadv_nc_mesh_init(bat_priv);
- if (ret < 0)
- goto err;
+ if (ret < 0) {
+ atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+ goto err_nc;
+ }
batadv_gw_init(bat_priv);
batadv_mcast_init(bat_priv);
@@ -222,8 +234,20 @@ int batadv_mesh_init(struct net_device *soft_iface)
return 0;
-err:
- batadv_mesh_free(soft_iface);
+err_nc:
+ batadv_dat_free(bat_priv);
+err_dat:
+ batadv_bla_free(bat_priv);
+err_bla:
+ batadv_v_mesh_free(bat_priv);
+err_v:
+ batadv_tt_free(bat_priv);
+err_tt:
+ batadv_originator_free(bat_priv);
+err_orig:
+ batadv_purge_outstanding_packets(bat_priv, NULL);
+ atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
+
return ret;
}
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index 9f06132e007d..0a7f1d36a6a8 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -152,8 +152,10 @@ int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
&batadv_nc_coding_hash_lock_class_key);
bat_priv->nc.decoding_hash = batadv_hash_new(128);
- if (!bat_priv->nc.decoding_hash)
+ if (!bat_priv->nc.decoding_hash) {
+ batadv_hash_destroy(bat_priv->nc.coding_hash);
goto err;
+ }
batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
&batadv_nc_decoding_hash_lock_class_key);
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index e0b3dace2020..4b7ad6684bc4 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -4162,8 +4162,10 @@ int batadv_tt_init(struct batadv_priv *bat_priv)
return ret;
ret = batadv_tt_global_init(bat_priv);
- if (ret < 0)
+ if (ret < 0) {
+ batadv_tt_local_table_free(bat_priv);
return ret;
+ }
batadv_tvlv_handler_register(bat_priv, batadv_tt_tvlv_ogm_handler_v1,
batadv_tt_tvlv_unicast_handler_v1,
--
2.33.1
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