From: Florian Westphal <fw@xxxxxxxxx>
Update of stateful object triggers:
WARNING: suspicious RCU usage
net/netfilter/nf_tables_api.c:7759 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
1 lock held by nft/3060:
#0: ffff88810f0578c8 (&nft_net->commit_mutex){+.+.}-{4:4}, [..]
... but this list is not protected by the transaction mutex but the
nfnl nftables subsystem mutex.
Switch to nft_obj_type_get which will acquire rcu read lock,
bump refcount, and returns the result.
v3: Dan Carpenter points out nft_obj_type_get returns error pointer, not
NULL, on error.
Fixes: dad3bdeef45f ("netfilter: nf_tables: fix memory leak during stateful obj update").
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index de8e48a5c62d..b7a817e483aa 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -7809,9 +7809,7 @@ static int nf_tables_updobj(const struct nft_ctx *ctx,
struct nft_trans *trans;
int err = -ENOMEM;
- if (!try_module_get(type->owner))
- return -ENOENT;
-
+ /* caller must have obtained type->owner reference. */
trans = nft_trans_alloc(ctx, NFT_MSG_NEWOBJ,
sizeof(struct nft_trans_obj));
if (!trans)
@@ -7879,15 +7877,16 @@ static int nf_tables_newobj(struct sk_buff *skb, const struct nfnl_info *info,
if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
return -EOPNOTSUPP;
- type = __nft_obj_type_get(objtype, family);
- if (WARN_ON_ONCE(!type))
- return -ENOENT;
-
if (!obj->ops->update)
return 0;
+ type = nft_obj_type_get(net, objtype, family);
+ if (WARN_ON_ONCE(IS_ERR(type)))
+ return PTR_ERR(type);
+
nft_ctx_init(&ctx, net, skb, info->nlh, family, table, NULL, nla);
+ /* type->owner reference is put when transaction object is released. */
return nf_tables_updobj(&ctx, type, nla[NFTA_OBJ_DATA], obj);
}
--
2.30.2
