netfilter: nf_tables: report use refcount overflow

Overflow use refcount checks are not complete.

Add helper function to deal with object reference counter tracking.
Report -EMFILE in case UINT_MAX is reached.

nft_use_dec() splats in case that reference counter underflows,
which should not ever happen.

Add nft_use_inc_restore() and nft_use_dec_restore() which are used
to restore reference counter from error and abort paths.

Use u32 in nft_flowtable and nft_object since helper functions cannot
work on bitfields.

Remove the few early incomplete checks now that the helper functions
are in place and used to check for refcount overflow.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 84f2fd8..640441a 100644 (file)
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1211,6 +1211,29 @@ int __nft_release_basechain(struct nft_ctx *ctx);
 
 unsigned int nft_do_chain(struct nft_pktinfo *pkt, void *priv);
 
+static inline bool nft_use_inc(u32 *use)
+{
+       if (*use == UINT_MAX)
+               return false;
+
+       (*use)++;
+
+       return true;
+}
+
+static inline void nft_use_dec(u32 *use)
+{
+       WARN_ON_ONCE((*use)-- == 0);
+}
+
+/* For error and abort path: restore use counter to previous state. */
+static inline void nft_use_inc_restore(u32 *use)
+{
+       WARN_ON_ONCE(!nft_use_inc(use));
+}
+
+#define nft_use_dec_restore    nft_use_dec
+
 /**
  *     struct nft_table - nf_tables table
  *
@@ -1296,8 +1319,8 @@ struct nft_object {
        struct list_head                list;
        struct rhlist_head              rhlhead;
        struct nft_object_hash_key      key;
-       u32                             genmask:2,
-                                       use:30;
+       u32                             genmask:2;
+       u32                             use;
        u64                             handle;
        u16                             udlen;
        u8                              *udata;
@@ -1399,8 +1422,8 @@ struct nft_flowtable {
        char                            *name;
        int                             hooknum;
        int                             ops_len;
-       u32                             genmask:2,
-                                       use:30;
+       u32                             genmask:2;
+       u32                             use;
        u64                             handle;
        /* runtime data below here */
        struct list_head                hook_list ____cacheline_aligned;

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 9573a8f..86b3c4d 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -253,8 +253,10 @@ int nf_tables_bind_chain(const struct nft_ctx *ctx, struct nft_chain *chain)
        if (chain->bound)
                return -EBUSY;
 
+       if (!nft_use_inc(&chain->use))
+               return -EMFILE;
+
        chain->bound = true;
-       chain->use++;
        nft_chain_trans_bind(ctx, chain);
 
        return 0;
@@ -437,7 +439,7 @@ static int nft_delchain(struct nft_ctx *ctx)
        if (IS_ERR(trans))
                return PTR_ERR(trans);
 
-       ctx->table->use--;
+       nft_use_dec(&ctx->table->use);
        nft_deactivate_next(ctx->net, ctx->chain);
 
        return 0;
@@ -476,7 +478,7 @@ nf_tables_delrule_deactivate(struct nft_ctx *ctx, struct nft_rule *rule)
        /* You cannot delete the same rule twice */
        if (nft_is_active_next(ctx->net, rule)) {
                nft_deactivate_next(ctx->net, rule);
-               ctx->chain->use--;
+               nft_use_dec(&ctx->chain->use);
                return 0;
        }
        return -ENOENT;
@@ -644,7 +646,7 @@ static int nft_delset(const struct nft_ctx *ctx, struct nft_set *set)
                nft_map_deactivate(ctx, set);
 
        nft_deactivate_next(ctx->net, set);
-       ctx->table->use--;
+       nft_use_dec(&ctx->table->use);
 
        return err;
 }
@@ -676,7 +678,7 @@ static int nft_delobj(struct nft_ctx *ctx, struct nft_object *obj)
                return err;
 
        nft_deactivate_next(ctx->net, obj);
-       ctx->table->use--;
+       nft_use_dec(&ctx->table->use);
 
        return err;
 }
@@ -711,7 +713,7 @@ static int nft_delflowtable(struct nft_ctx *ctx,
                return err;
 
        nft_deactivate_next(ctx->net, flowtable);
-       ctx->table->use--;
+       nft_use_dec(&ctx->table->use);
 
        return err;
 }
@@ -2396,9 +2398,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
        struct nft_chain *chain;
        int err;
 
-       if (table->use == UINT_MAX)
-               return -EOVERFLOW;
-
        if (nla[NFTA_CHAIN_HOOK]) {
                struct nft_stats __percpu *stats = NULL;
                struct nft_chain_hook hook = {};
@@ -2494,6 +2493,11 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
        if (err < 0)
                goto err_destroy_chain;
 
+       if (!nft_use_inc(&table->use)) {
+               err = -EMFILE;
+               goto err_use;
+       }
+
        trans = nft_trans_chain_add(ctx, NFT_MSG_NEWCHAIN);
        if (IS_ERR(trans)) {
                err = PTR_ERR(trans);
@@ -2510,10 +2514,11 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
                goto err_unregister_hook;
        }
 
-       table->use++;
-
        return 0;
+
 err_unregister_hook:
+       nft_use_dec_restore(&table->use);
+err_use:
        nf_tables_unregister_hook(net, table, chain);
 err_destroy_chain:
        nf_tables_chain_destroy(ctx);
@@ -3840,9 +3845,6 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
                        return -EINVAL;
                handle = nf_tables_alloc_handle(table);
 
-               if (chain->use == UINT_MAX)
-                       return -EOVERFLOW;
-
                if (nla[NFTA_RULE_POSITION]) {
                        pos_handle = be64_to_cpu(nla_get_be64(nla[NFTA_RULE_POSITION]));
                        old_rule = __nft_rule_lookup(chain, pos_handle);
@@ -3936,6 +3938,11 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
                }
        }
 
+       if (!nft_use_inc(&chain->use)) {
+               err = -EMFILE;
+               goto err_release_rule;
+       }
+
        if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
                err = nft_delrule(&ctx, old_rule);
                if (err < 0)
@@ -3967,7 +3974,6 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
                }
        }
        kvfree(expr_info);
-       chain->use++;
 
        if (flow)
                nft_trans_flow_rule(trans) = flow;
@@ -3978,6 +3984,7 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
        return 0;
 
 err_destroy_flow_rule:
+       nft_use_dec_restore(&chain->use);
        if (flow)
                nft_flow_rule_destroy(flow);
 err_release_rule:
@@ -5014,9 +5021,15 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
        alloc_size = sizeof(*set) + size + udlen;
        if (alloc_size < size || alloc_size > INT_MAX)
                return -ENOMEM;
+
+       if (!nft_use_inc(&table->use))
+               return -EMFILE;
+
        set = kvzalloc(alloc_size, GFP_KERNEL_ACCOUNT);
-       if (!set)
-               return -ENOMEM;
+       if (!set) {
+               err = -ENOMEM;
+               goto err_alloc;
+       }
 
        name = nla_strdup(nla[NFTA_SET_NAME], GFP_KERNEL_ACCOUNT);
        if (!name) {
@@ -5074,7 +5087,7 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
                goto err_set_expr_alloc;
 
        list_add_tail_rcu(&set->list, &table->sets);
-       table->use++;
+
        return 0;
 
 err_set_expr_alloc:
@@ -5086,6 +5099,9 @@ err_set_init:
        kfree(set->name);
 err_set_name:
        kvfree(set);
+err_alloc:
+       nft_use_dec_restore(&table->use);
+
        return err;
 }
 
@@ -5224,9 +5240,6 @@ int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
        struct nft_set_binding *i;
        struct nft_set_iter iter;
 
-       if (set->use == UINT_MAX)
-               return -EOVERFLOW;
-
        if (!list_empty(&set->bindings) && nft_set_is_anonymous(set))
                return -EBUSY;
 
@@ -5254,10 +5267,12 @@ int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
                        return iter.err;
        }
 bind:
+       if (!nft_use_inc(&set->use))
+               return -EMFILE;
+
        binding->chain = ctx->chain;
        list_add_tail_rcu(&binding->list, &set->bindings);
        nft_set_trans_bind(ctx, set);
-       set->use++;
 
        return 0;
 }
@@ -5331,7 +5346,7 @@ void nf_tables_activate_set(const struct nft_ctx *ctx, struct nft_set *set)
                nft_clear(ctx->net, set);
        }
 
-       set->use++;
+       nft_use_inc_restore(&set->use);
 }
 EXPORT_SYMBOL_GPL(nf_tables_activate_set);
 
@@ -5347,7 +5362,7 @@ void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set,
                else
                        list_del_rcu(&binding->list);
 
-               set->use--;
+               nft_use_dec(&set->use);
                break;
        case NFT_TRANS_PREPARE:
                if (nft_set_is_anonymous(set)) {
@@ -5356,7 +5371,7 @@ void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set,
 
                        nft_deactivate_next(ctx->net, set);
                }
-               set->use--;
+               nft_use_dec(&set->use);
                return;
        case NFT_TRANS_ABORT:
        case NFT_TRANS_RELEASE:
@@ -5364,7 +5379,7 @@ void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set,
                    set->flags & (NFT_SET_MAP | NFT_SET_OBJECT))
                        nft_map_deactivate(ctx, set);
 
-               set->use--;
+               nft_use_dec(&set->use);
                fallthrough;
        default:
                nf_tables_unbind_set(ctx, set, binding,
@@ -6155,7 +6170,7 @@ void nft_set_elem_destroy(const struct nft_set *set, void *elem,
                nft_set_elem_expr_destroy(&ctx, nft_set_ext_expr(ext));
 
        if (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF))
-               (*nft_set_ext_obj(ext))->use--;
+               nft_use_dec(&(*nft_set_ext_obj(ext))->use);
        kfree(elem);
 }
 EXPORT_SYMBOL_GPL(nft_set_elem_destroy);
@@ -6657,8 +6672,16 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
                                     set->objtype, genmask);
                if (IS_ERR(obj)) {
                        err = PTR_ERR(obj);
+                       obj = NULL;
                        goto err_parse_key_end;
                }
+
+               if (!nft_use_inc(&obj->use)) {
+                       err = -EMFILE;
+                       obj = NULL;
+                       goto err_parse_key_end;
+               }
+
                err = nft_set_ext_add(&tmpl, NFT_SET_EXT_OBJREF);
                if (err < 0)
                        goto err_parse_key_end;
@@ -6727,10 +6750,9 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
        if (flags)
                *nft_set_ext_flags(ext) = flags;
 
-       if (obj) {
+       if (obj)
                *nft_set_ext_obj(ext) = obj;
-               obj->use++;
-       }
+
        if (ulen > 0) {
                if (nft_set_ext_check(&tmpl, NFT_SET_EXT_USERDATA, ulen) < 0) {
                        err = -EINVAL;
@@ -6798,12 +6820,13 @@ err_element_clash:
        kfree(trans);
 err_elem_free:
        nf_tables_set_elem_destroy(ctx, set, elem.priv);
-       if (obj)
-               obj->use--;
 err_parse_data:
        if (nla[NFTA_SET_ELEM_DATA] != NULL)
                nft_data_release(&elem.data.val, desc.type);
 err_parse_key_end:
+       if (obj)
+               nft_use_dec_restore(&obj->use);
+
        nft_data_release(&elem.key_end.val, NFT_DATA_VALUE);
 err_parse_key:
        nft_data_release(&elem.key.val, NFT_DATA_VALUE);
@@ -6883,7 +6906,7 @@ void nft_data_hold(const struct nft_data *data, enum nft_data_types type)
                case NFT_JUMP:
                case NFT_GOTO:
                        chain = data->verdict.chain;
-                       chain->use++;
+                       nft_use_inc_restore(&chain->use);
                        break;
                }
        }
@@ -6898,7 +6921,7 @@ static void nft_setelem_data_activate(const struct net *net,
        if (nft_set_ext_exists(ext, NFT_SET_EXT_DATA))
                nft_data_hold(nft_set_ext_data(ext), set->dtype);
        if (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF))
-               (*nft_set_ext_obj(ext))->use++;
+               nft_use_inc_restore(&(*nft_set_ext_obj(ext))->use);
 }
 
 static void nft_setelem_data_deactivate(const struct net *net,
@@ -6910,7 +6933,7 @@ static void nft_setelem_data_deactivate(const struct net *net,
        if (nft_set_ext_exists(ext, NFT_SET_EXT_DATA))
                nft_data_release(nft_set_ext_data(ext), set->dtype);
        if (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF))
-               (*nft_set_ext_obj(ext))->use--;
+               nft_use_dec(&(*nft_set_ext_obj(ext))->use);
 }
 
 static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
@@ -7453,9 +7476,14 @@ static int nf_tables_newobj(struct sk_buff *skb, const struct nfnl_info *info,
 
        nft_ctx_init(&ctx, net, skb, info->nlh, family, table, NULL, nla);
 
+       if (!nft_use_inc(&table->use))
+               return -EMFILE;
+
        type = nft_obj_type_get(net, objtype);
-       if (IS_ERR(type))
-               return PTR_ERR(type);
+       if (IS_ERR(type)) {
+               err = PTR_ERR(type);
+               goto err_type;
+       }
 
        obj = nft_obj_init(&ctx, type, nla[NFTA_OBJ_DATA]);
        if (IS_ERR(obj)) {
@@ -7489,7 +7517,7 @@ static int nf_tables_newobj(struct sk_buff *skb, const struct nfnl_info *info,
                goto err_obj_ht;
 
        list_add_tail_rcu(&obj->list, &table->objects);
-       table->use++;
+
        return 0;
 err_obj_ht:
        /* queued in transaction log */
@@ -7505,6 +7533,9 @@ err_strdup:
        kfree(obj);
 err_init:
        module_put(type->owner);
+err_type:
+       nft_use_dec_restore(&table->use);
+
        return err;
 }
 
@@ -7906,7 +7937,7 @@ void nf_tables_deactivate_flowtable(const struct nft_ctx *ctx,
        case NFT_TRANS_PREPARE:
        case NFT_TRANS_ABORT:
        case NFT_TRANS_RELEASE:
-               flowtable->use--;
+               nft_use_dec(&flowtable->use);
                fallthrough;
        default:
                return;
@@ -8260,9 +8291,14 @@ static int nf_tables_newflowtable(struct sk_buff *skb,
 
        nft_ctx_init(&ctx, net, skb, info->nlh, family, table, NULL, nla);
 
+       if (!nft_use_inc(&table->use))
+               return -EMFILE;
+
        flowtable = kzalloc(sizeof(*flowtable), GFP_KERNEL_ACCOUNT);
-       if (!flowtable)
-               return -ENOMEM;
+       if (!flowtable) {
+               err = -ENOMEM;
+               goto flowtable_alloc;
+       }
 
        flowtable->table = table;
        flowtable->handle = nf_tables_alloc_handle(table);
@@ -8317,7 +8353,6 @@ static int nf_tables_newflowtable(struct sk_buff *skb,
                goto err5;
 
        list_add_tail_rcu(&flowtable->list, &table->flowtables);
-       table->use++;
 
        return 0;
 err5:
@@ -8334,6 +8369,9 @@ err2:
        kfree(flowtable->name);
 err1:
        kfree(flowtable);
+flowtable_alloc:
+       nft_use_dec_restore(&table->use);
+
        return err;
 }
 
@@ -9713,7 +9751,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
                                 */
                                if (nft_set_is_anonymous(nft_trans_set(trans)) &&
                                    !list_empty(&nft_trans_set(trans)->bindings))
-                                       trans->ctx.table->use--;
+                                       nft_use_dec(&trans->ctx.table->use);
                        }
                        nf_tables_set_notify(&trans->ctx, nft_trans_set(trans),
                                             NFT_MSG_NEWSET, GFP_KERNEL);
@@ -9943,7 +9981,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                                        nft_trans_destroy(trans);
                                        break;
                                }
-                               trans->ctx.table->use--;
+                               nft_use_dec_restore(&trans->ctx.table->use);
                                nft_chain_del(trans->ctx.chain);
                                nf_tables_unregister_hook(trans->ctx.net,
                                                          trans->ctx.table,
@@ -9956,7 +9994,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                                list_splice(&nft_trans_chain_hooks(trans),
                                            &nft_trans_basechain(trans)->hook_list);
                        } else {
-                               trans->ctx.table->use++;
+                               nft_use_inc_restore(&trans->ctx.table->use);
                                nft_clear(trans->ctx.net, trans->ctx.chain);
                        }
                        nft_trans_destroy(trans);
@@ -9966,7 +10004,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                                nft_trans_destroy(trans);
                                break;
                        }
-                       trans->ctx.chain->use--;
+                       nft_use_dec_restore(&trans->ctx.chain->use);
                        list_del_rcu(&nft_trans_rule(trans)->list);
                        nft_rule_expr_deactivate(&trans->ctx,
                                                 nft_trans_rule(trans),
@@ -9976,7 +10014,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                        break;
                case NFT_MSG_DELRULE:
                case NFT_MSG_DESTROYRULE:
-                       trans->ctx.chain->use++;
+                       nft_use_inc_restore(&trans->ctx.chain->use);
                        nft_clear(trans->ctx.net, nft_trans_rule(trans));
                        nft_rule_expr_activate(&trans->ctx, nft_trans_rule(trans));
                        if (trans->ctx.chain->flags & NFT_CHAIN_HW_OFFLOAD)
@@ -9989,7 +10027,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                                nft_trans_destroy(trans);
                                break;
                        }
-                       trans->ctx.table->use--;
+                       nft_use_dec_restore(&trans->ctx.table->use);
                        if (nft_trans_set_bound(trans)) {
                                nft_trans_destroy(trans);
                                break;
@@ -9998,7 +10036,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                        break;
                case NFT_MSG_DELSET:
                case NFT_MSG_DESTROYSET:
-                       trans->ctx.table->use++;
+                       nft_use_inc_restore(&trans->ctx.table->use);
                        nft_clear(trans->ctx.net, nft_trans_set(trans));
                        if (nft_trans_set(trans)->flags & (NFT_SET_MAP | NFT_SET_OBJECT))
                                nft_map_activate(&trans->ctx, nft_trans_set(trans));
@@ -10042,13 +10080,13 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                                nft_obj_destroy(&trans->ctx, nft_trans_obj_newobj(trans));
                                nft_trans_destroy(trans);
                        } else {
-                               trans->ctx.table->use--;
+                               nft_use_dec_restore(&trans->ctx.table->use);
                                nft_obj_del(nft_trans_obj(trans));
                        }
                        break;
                case NFT_MSG_DELOBJ:
                case NFT_MSG_DESTROYOBJ:
-                       trans->ctx.table->use++;
+                       nft_use_inc_restore(&trans->ctx.table->use);
                        nft_clear(trans->ctx.net, nft_trans_obj(trans));
                        nft_trans_destroy(trans);
                        break;
@@ -10057,7 +10095,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                                nft_unregister_flowtable_net_hooks(net,
                                                &nft_trans_flowtable_hooks(trans));
                        } else {
-                               trans->ctx.table->use--;
+                               nft_use_dec_restore(&trans->ctx.table->use);
                                list_del_rcu(&nft_trans_flowtable(trans)->list);
                                nft_unregister_flowtable_net_hooks(net,
                                                &nft_trans_flowtable(trans)->hook_list);
@@ -10069,7 +10107,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
                                list_splice(&nft_trans_flowtable_hooks(trans),
                                            &nft_trans_flowtable(trans)->hook_list);
                        } else {
-                               trans->ctx.table->use++;
+                               nft_use_inc_restore(&trans->ctx.table->use);
                                nft_clear(trans->ctx.net, nft_trans_flowtable(trans));
                        }
                        nft_trans_destroy(trans);
@@ -10518,8 +10556,9 @@ static int nft_verdict_init(const struct nft_ctx *ctx, struct nft_data *data,
                if (desc->flags & NFT_DATA_DESC_SETELEM &&
                    chain->flags & NFT_CHAIN_BINDING)
                        return -EINVAL;
+               if (!nft_use_inc(&chain->use))
+                       return -EMFILE;
 
-               chain->use++;
                data->verdict.chain = chain;
                break;
        }
@@ -10537,7 +10576,7 @@ static void nft_verdict_uninit(const struct nft_data *data)
        case NFT_JUMP:
        case NFT_GOTO:
                chain = data->verdict.chain;
-               chain->use--;
+               nft_use_dec(&chain->use);
                break;
        }
 }
@@ -10706,11 +10745,11 @@ int __nft_release_basechain(struct nft_ctx *ctx)
        nf_tables_unregister_hook(ctx->net, ctx->chain->table, ctx->chain);
        list_for_each_entry_safe(rule, nr, &ctx->chain->rules, list) {
                list_del(&rule->list);
-               ctx->chain->use--;
+               nft_use_dec(&ctx->chain->use);
                nf_tables_rule_release(ctx, rule);
        }
        nft_chain_del(ctx->chain);
-       ctx->table->use--;
+       nft_use_dec(&ctx->table->use);
        nf_tables_chain_destroy(ctx);
 
        return 0;
@@ -10760,18 +10799,18 @@ static void __nft_release_table(struct net *net, struct nft_table *table)
                ctx.chain = chain;
                list_for_each_entry_safe(rule, nr, &chain->rules, list) {
                        list_del(&rule->list);
-                       chain->use--;
+                       nft_use_dec(&chain->use);
                        nf_tables_rule_release(&ctx, rule);
                }
        }
        list_for_each_entry_safe(flowtable, nf, &table->flowtables, list) {
                list_del(&flowtable->list);
-               table->use--;
+               nft_use_dec(&table->use);
                nf_tables_flowtable_destroy(flowtable);
        }
        list_for_each_entry_safe(set, ns, &table->sets, list) {
                list_del(&set->list);
-               table->use--;
+               nft_use_dec(&table->use);
                if (set->flags & (NFT_SET_MAP | NFT_SET_OBJECT))
                        nft_map_deactivate(&ctx, set);
 
@@ -10779,13 +10818,13 @@ static void __nft_release_table(struct net *net, struct nft_table *table)
        }
        list_for_each_entry_safe(obj, ne, &table->objects, list) {
                nft_obj_del(obj);
-               table->use--;
+               nft_use_dec(&table->use);
                nft_obj_destroy(&ctx, obj);
        }
        list_for_each_entry_safe(chain, nc, &table->chains, list) {
                ctx.chain = chain;
                nft_chain_del(chain);
-               table->use--;
+               nft_use_dec(&table->use);
                nf_tables_chain_destroy(&ctx);
        }
        nf_tables_table_destroy(&ctx);

diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 5ef9146..ab3362c 100644 (file)
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -408,8 +408,10 @@ static int nft_flow_offload_init(const struct nft_ctx *ctx,
        if (IS_ERR(flowtable))
                return PTR_ERR(flowtable);
 
+       if (!nft_use_inc(&flowtable->use))
+               return -EMFILE;
+
        priv->flowtable = flowtable;
-       flowtable->use++;
 
        return nf_ct_netns_get(ctx->net, ctx->family);
 }
@@ -428,7 +430,7 @@ static void nft_flow_offload_activate(const struct nft_ctx *ctx,
 {
        struct nft_flow_offload *priv = nft_expr_priv(expr);
 
-       priv->flowtable->use++;
+       nft_use_inc_restore(&priv->flowtable->use);
 }
 
 static void nft_flow_offload_destroy(const struct nft_ctx *ctx,

diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c
index 3d76ebf..407d719 100644 (file)
--- a/net/netfilter/nft_immediate.c
+++ b/net/netfilter/nft_immediate.c
@@ -159,7 +159,7 @@ static void nft_immediate_deactivate(const struct nft_ctx *ctx,
                        default:
                                nft_chain_del(chain);
                                chain->bound = false;
-                               chain->table->use--;
+                               nft_use_dec(&chain->table->use);
                                break;
                        }
                        break;
@@ -198,7 +198,7 @@ static void nft_immediate_destroy(const struct nft_ctx *ctx,
                 * let the transaction records release this chain and its rules.
                 */
                if (chain->bound) {
-                       chain->use--;
+                       nft_use_dec(&chain->use);
                        break;
                }
 
@@ -206,9 +206,9 @@ static void nft_immediate_destroy(const struct nft_ctx *ctx,
                chain_ctx = *ctx;
                chain_ctx.chain = chain;
 
-               chain->use--;
+               nft_use_dec(&chain->use);
                list_for_each_entry_safe(rule, n, &chain->rules, list) {
-                       chain->use--;
+                       nft_use_dec(&chain->use);
                        list_del(&rule->list);
                        nf_tables_rule_destroy(&chain_ctx, rule);
                }

diff --git a/net/netfilter/nft_objref.c b/net/netfilter/nft_objref.c
index a48dd5b..509011b 100644 (file)
--- a/net/netfilter/nft_objref.c
+++ b/net/netfilter/nft_objref.c
@@ -41,8 +41,10 @@ static int nft_objref_init(const struct nft_ctx *ctx,
        if (IS_ERR(obj))
                return -ENOENT;
 
+       if (!nft_use_inc(&obj->use))
+               return -EMFILE;
+
        nft_objref_priv(expr) = obj;
-       obj->use++;
 
        return 0;
 }
@@ -72,7 +74,7 @@ static void nft_objref_deactivate(const struct nft_ctx *ctx,
        if (phase == NFT_TRANS_COMMIT)
                return;
 
-       obj->use--;
+       nft_use_dec(&obj->use);
 }
 
 static void nft_objref_activate(const struct nft_ctx *ctx,
@@ -80,7 +82,7 @@ static void nft_objref_activate(const struct nft_ctx *ctx,
 {
        struct nft_object *obj = nft_objref_priv(expr);
 
-       obj->use++;
+       nft_use_inc_restore(&obj->use);
 }
 
 static const struct nft_expr_ops nft_objref_ops = {