[PATCH 6.1.y] netfilter: nf_tables: make nft_object rhltable per table
From: Suraj Jitindar Singh <hidden>
Date: 2026-09-04 01:31:09
Also in:
netfilter-devel, stable
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Pablo Neira Ayuso <pablo@netfilter.org>
commit f4f699790590bd0896c48a71e9232a65198f92f0 upstream.
The nft_object rhltable is global, this allows for accessing objects
that are being dismangled from lookup path by other existing netns.
Given the nft_obj_destroy() releases the object inmediately, this might
lead to use-after-free of these objects that are being released.
Make the existing rhltable per table to address this issue to deal with
with the nft_rcv_nl_event() path too.
Update nft_obj_lookup() to take the table as non-const, otherwise,
compiler complains when passing the objname_ht to rhltable_lookup().
Fixes: 4d44175aa5bb ("netfilter: nf_tables: handle nft_object lookups via rhltable")
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
[ 6.1: Conflicts in nf_tables_api.c because 6.1 lacks three mainline
refactors: 0be908750162 ("netfilter: nf_tables: pass nft_table to
destroy function", v6.11), e169285f8c56 ("netfilter: nf_tables: do
not store nft_ctx in transaction objects", v6.11) and f80a612dd77c
("netfilter: nf_tables: add support to destroy operation", v6.3).
As a result 6.1's nf_tables_table_destroy() still takes an nft_ctx;
struct nft_trans still embeds an nft_ctx (so the owning table is
trans->ctx.table, not a per-transaction table local); and the commit
path has no NFT_MSG_DESTROYOBJ case. Resolved by destroying the
per-table objname_ht via ctx->table in nf_tables_table_destroy(), and
by passing the owning table trans->ctx.table to nft_obj_del() in the
commit and abort paths; 6.1's single NFT_MSG_DELOBJ case is retained.
The header and all other hunks applied cleanly. ]
Signed-off-by: Suraj Jitindar Singh <redacted>
---
include/net/netfilter/nf_tables.h | 4 +++-
net/netfilter/nf_tables_api.c | 34 +++++++++++++++----------------
2 files changed, 19 insertions(+), 19 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 4e8cf4e13f8f..6c82feab2ad5 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h@@ -1211,6 +1211,7 @@ static inline void nft_use_inc_restore(u32 *use) * @sets: sets in the table * @objects: stateful objects in the table * @flowtables: flow tables in the table + * @objname_ht: hashtable for objects lookup by name * @hgenerator: handle generator state * @handle: table handle * @use: number of chain references to this table
@@ -1226,6 +1227,7 @@ struct nft_table { struct list_head sets; struct list_head objects; struct list_head flowtables; + struct rhltable objname_ht; u64 hgenerator; u64 handle; u32 use;
@@ -1304,7 +1306,7 @@ static inline void *nft_obj_data(const struct nft_object *obj) #define nft_expr_obj(expr) *((struct nft_object **)nft_expr_priv(expr)) struct nft_object *nft_obj_lookup(const struct net *net, - const struct nft_table *table, + struct nft_table *table, const struct nlattr *nla, u32 objtype, u8 genmask);
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 7240f494d83b..71ada0af4c85 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c@@ -42,8 +42,6 @@ enum { NFT_VALIDATE_DO, }; -static struct rhltable nft_objname_ht; - static u32 nft_chain_hash(const void *data, u32 len, u32 seed); static u32 nft_chain_hash_obj(const void *data, u32 len, u32 seed); static int nft_chain_hash_cmp(struct rhashtable_compare_arg *, const void *);
@@ -1419,6 +1417,10 @@ static int nf_tables_newtable(struct sk_buff *skb, const struct nfnl_info *info, if (err) goto err_chain_ht; + err = rhltable_init(&table->objname_ht, &nft_objname_ht_params); + if (err < 0) + goto err_obj_ht; + INIT_LIST_HEAD(&table->chains); INIT_LIST_HEAD(&table->sets); INIT_LIST_HEAD(&table->objects);
@@ -1437,6 +1439,8 @@ static int nf_tables_newtable(struct sk_buff *skb, const struct nfnl_info *info, list_add_tail_rcu(&table->list, &nft_net->tables); return 0; err_trans: + rhltable_destroy(&table->objname_ht); +err_obj_ht: rhltable_destroy(&table->chains_ht); err_chain_ht: kfree(table->udata);
@@ -1599,6 +1603,7 @@ static void nf_tables_table_destroy(struct nft_ctx *ctx) return; rhltable_destroy(&ctx->table->chains_ht); + rhltable_destroy(&ctx->table->objname_ht); kfree(ctx->table->name); kfree(ctx->table->udata); kfree(ctx->table);
@@ -7151,7 +7156,7 @@ void nft_unregister_obj(struct nft_object_type *obj_type) EXPORT_SYMBOL_GPL(nft_unregister_obj); struct nft_object *nft_obj_lookup(const struct net *net, - const struct nft_table *table, + struct nft_table *table, const struct nlattr *nla, u32 objtype, u8 genmask) {
@@ -7167,7 +7172,7 @@ struct nft_object *nft_obj_lookup(const struct net *net, !lockdep_commit_lock_is_held(net)); rcu_read_lock(); - list = rhltable_lookup(&nft_objname_ht, &k, nft_objname_ht_params); + list = rhltable_lookup(&table->objname_ht, &k, nft_objname_ht_params); if (!list) goto out;
@@ -7446,7 +7451,7 @@ static int nf_tables_newobj(struct sk_buff *skb, const struct nfnl_info *info, if (err < 0) goto err_trans; - err = rhltable_insert(&nft_objname_ht, &obj->rhlhead, + err = rhltable_insert(&table->objname_ht, &obj->rhlhead, nft_objname_ht_params); if (err < 0) goto err_obj_ht;
@@ -7642,8 +7647,8 @@ nf_tables_getobj_single(u32 portid, const struct nfnl_info *info, struct netlink_ext_ack *extack = info->extack; u8 genmask = nft_genmask_cur(info->net); u8 family = info->nfmsg->nfgen_family; - const struct nft_table *table; struct net *net = info->net; + struct nft_table *table; struct nft_object *obj; struct sk_buff *skb2; u32 objtype;
@@ -9310,9 +9315,9 @@ static void nf_tables_commit_chain(struct net *net, struct nft_chain *chain) nf_tables_commit_chain_free_rules_old(g0); } -static void nft_obj_del(struct nft_object *obj) +static void nft_obj_del(struct nft_table *table, struct nft_object *obj) { - rhltable_remove(&nft_objname_ht, &obj->rhlhead, nft_objname_ht_params); + rhltable_remove(&table->objname_ht, &obj->rhlhead, nft_objname_ht_params); list_del_rcu(&obj->list); }
@@ -9963,7 +9968,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb) } break; case NFT_MSG_DELOBJ: - nft_obj_del(nft_trans_obj(trans)); + nft_obj_del(trans->ctx.table, nft_trans_obj(trans)); nf_tables_obj_notify(&trans->ctx, nft_trans_obj(trans), NFT_MSG_DELOBJ); break;
@@ -10222,7 +10227,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action) nft_trans_destroy(trans); } else { nft_use_dec_restore(&trans->ctx.table->use); - nft_obj_del(nft_trans_obj(trans)); + nft_obj_del(trans->ctx.table, nft_trans_obj(trans)); } break; case NFT_MSG_DELOBJ:
@@ -10860,7 +10865,7 @@ static void __nft_release_table(struct net *net, struct nft_table *table) nft_set_destroy(&ctx, set); } list_for_each_entry_safe(obj, ne, &table->objects, list) { - nft_obj_del(obj); + nft_obj_del(table, obj); nft_use_dec(&table->use); nft_obj_destroy(&ctx, obj); }
@@ -11023,10 +11028,6 @@ static int __init nf_tables_module_init(void) if (err < 0) goto err_netdev_notifier; - err = rhltable_init(&nft_objname_ht, &nft_objname_ht_params); - if (err < 0) - goto err_rht_objname; - err = nft_offload_init(); if (err < 0) goto err_offload;
@@ -11049,8 +11050,6 @@ static int __init nf_tables_module_init(void) err_netlink_notifier: nft_offload_exit(); err_offload: - rhltable_destroy(&nft_objname_ht); -err_rht_objname: unregister_netdevice_notifier(&nf_tables_flowtable_notifier); err_netdev_notifier: nf_tables_core_module_exit();
@@ -11074,7 +11073,6 @@ static void __exit nf_tables_module_exit(void) cancel_work_sync(&trans_gc_work); cancel_work_sync(&trans_destroy_work); rcu_barrier(); - rhltable_destroy(&nft_objname_ht); nf_tables_core_module_exit(); }
--
2.47.3