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authorPavel Skripkin <paskripkin@gmail.com>2021-10-24 16:13:56 +0300
committerDavid S. Miller <davem@davemloft.net>2021-10-26 16:47:12 +0300
commit6f68cd634856f8ca93bafd623ba5357e0f648c68 (patch)
tree6e79fd6203a535c10bd11391c9e6f51a7070a6eb /net/batman-adv/bridge_loop_avoidance.c
parentfa40d9734a57bcbfa79a280189799f76c88f7bb0 (diff)
downloadlinux-6f68cd634856f8ca93bafd623ba5357e0f648c68.tar.xz
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@syzkaller.appspotmail.com Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> Acked-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/batman-adv/bridge_loop_avoidance.c')
-rw-r--r--net/batman-adv/bridge_loop_avoidance.c8
1 files changed, 6 insertions, 2 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);