--- /dev/null
+From stable-owner@vger.kernel.org Sun Aug 13 00:09:51 2023
+From: Pablo Neira Ayuso <pablo@netfilter.org>
+Date: Sun, 13 Aug 2023 00:09:41 +0200
+Subject: netfilter: nf_tables: report use refcount overflow
+To: netfilter-devel@vger.kernel.org
+Cc: gregkh@linuxfoundation.org, stable@vger.kernel.org, sashal@kernel.org
+Message-ID: <20230812220941.56747-2-pablo@netfilter.org>
+
+From: Pablo Neira Ayuso <pablo@netfilter.org>
+
+commit 1689f25924ada8fe14a4a82c38925d04994c7142 upstream.
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/net/netfilter/nf_tables.h | 27 ++++++-
+ net/netfilter/nf_tables_api.c | 143 +++++++++++++++++++++++---------------
+ net/netfilter/nft_objref.c | 8 +-
+ 3 files changed, 119 insertions(+), 59 deletions(-)
+
+--- a/include/net/netfilter/nf_tables.h
++++ b/include/net/netfilter/nf_tables.h
+@@ -968,6 +968,29 @@ int __nft_release_basechain(struct nft_c
+
+ 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
+ *
+@@ -1051,8 +1074,8 @@ struct nft_object {
+ struct list_head list;
+ char *name;
+ struct nft_table *table;
+- u32 genmask:2,
+- use:30;
++ u32 genmask:2;
++ u32 use;
+ /* runtime data below here */
+ const struct nft_object_ops *ops ____cacheline_aligned;
+ unsigned char data[]
+--- a/net/netfilter/nf_tables_api.c
++++ b/net/netfilter/nf_tables_api.c
+@@ -248,7 +248,7 @@ static int nft_delchain(struct nft_ctx *
+ if (err < 0)
+ return err;
+
+- ctx->table->use--;
++ nft_use_dec(&ctx->table->use);
+ nft_deactivate_next(ctx->net, ctx->chain);
+
+ return err;
+@@ -289,7 +289,7 @@ nf_tables_delrule_deactivate(struct nft_
+ /* 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;
+@@ -378,7 +378,7 @@ static int nft_delset(const struct nft_c
+ return err;
+
+ nft_deactivate_next(ctx->net, set);
+- ctx->table->use--;
++ nft_use_dec(&ctx->table->use);
+
+ return err;
+ }
+@@ -410,7 +410,7 @@ static int nft_delobj(struct nft_ctx *ct
+ return err;
+
+ nft_deactivate_next(ctx->net, obj);
+- ctx->table->use--;
++ nft_use_dec(&ctx->table->use);
+
+ return err;
+ }
+@@ -1421,9 +1421,6 @@ static int nf_tables_addchain(struct nft
+ unsigned int i;
+ int err;
+
+- if (table->use == UINT_MAX)
+- return -EOVERFLOW;
+-
+ if (nla[NFTA_CHAIN_HOOK]) {
+ struct nft_chain_hook hook;
+ struct nf_hook_ops *ops;
+@@ -1491,16 +1488,22 @@ static int nf_tables_addchain(struct nft
+ if (err < 0)
+ goto err1;
+
++ if (!nft_use_inc(&table->use)) {
++ err = -EMFILE;
++ goto err_use;
++ }
++
+ ctx->chain = chain;
+ err = nft_trans_chain_add(ctx, NFT_MSG_NEWCHAIN);
+ if (err < 0)
+ goto err2;
+
+- table->use++;
+ list_add_tail_rcu(&chain->list, &table->chains);
+
+ return 0;
+ err2:
++ nft_use_dec_restore(&table->use);
++err_use:
+ nf_tables_unregister_hooks(net, table, chain, afi->nops);
+ err1:
+ nf_tables_chain_destroy(chain);
+@@ -2371,9 +2374,6 @@ static int nf_tables_newrule(struct net
+ if (!create || nlh->nlmsg_flags & NLM_F_REPLACE)
+ return -EINVAL;
+ handle = nf_tables_alloc_handle(table);
+-
+- if (chain->use == UINT_MAX)
+- return -EOVERFLOW;
+ }
+
+ if (nla[NFTA_RULE_POSITION]) {
+@@ -2441,23 +2441,28 @@ static int nf_tables_newrule(struct net
+ expr = nft_expr_next(expr);
+ }
+
++ if (!nft_use_inc(&chain->use)) {
++ err = -EMFILE;
++ goto err2;
++ }
++
+ if (nlh->nlmsg_flags & NLM_F_REPLACE) {
+ trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
+ if (trans == NULL) {
+ err = -ENOMEM;
+- goto err2;
++ goto err_destroy_flow_rule;
+ }
+ err = nft_delrule(&ctx, old_rule);
+ if (err < 0) {
+ nft_trans_destroy(trans);
+- goto err2;
++ goto err_destroy_flow_rule;
+ }
+
+ list_add_tail_rcu(&rule->list, &old_rule->list);
+ } else {
+ if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
+ err = -ENOMEM;
+- goto err2;
++ goto err_destroy_flow_rule;
+ }
+
+ if (nlh->nlmsg_flags & NLM_F_APPEND) {
+@@ -2472,9 +2477,11 @@ static int nf_tables_newrule(struct net
+ list_add_rcu(&rule->list, &chain->rules);
+ }
+ }
+- chain->use++;
++
+ return 0;
+
++err_destroy_flow_rule:
++ nft_use_dec_restore(&chain->use);
+ err2:
+ nft_rule_expr_deactivate(&ctx, rule, NFT_TRANS_PREPARE_ERROR);
+ nf_tables_rule_destroy(&ctx, rule);
+@@ -3262,10 +3269,15 @@ static int nf_tables_newset(struct net *
+ if (ops->privsize != NULL)
+ size = ops->privsize(nla, &desc);
+
++ if (!nft_use_inc(&table->use)) {
++ err = -EMFILE;
++ goto err1;
++ }
++
+ set = kvzalloc(sizeof(*set) + size + udlen, GFP_KERNEL);
+ if (!set) {
+ err = -ENOMEM;
+- goto err1;
++ goto err_alloc;
+ }
+
+ name = nla_strdup(nla[NFTA_SET_NAME], GFP_KERNEL);
+@@ -3310,7 +3322,7 @@ static int nf_tables_newset(struct net *
+ goto err4;
+
+ list_add_tail_rcu(&set->list, &table->sets);
+- table->use++;
++
+ return 0;
+
+ err4:
+@@ -3319,6 +3331,8 @@ err3:
+ kfree(set->name);
+ err2:
+ kvfree(set);
++err_alloc:
++ nft_use_dec_restore(&table->use);
+ err1:
+ module_put(ops->type->owner);
+ return err;
+@@ -3393,9 +3407,6 @@ int nf_tables_bind_set(const struct nft_
+ struct nft_set_binding *i;
+ struct nft_set_iter iter;
+
+- if (set->use == UINT_MAX)
+- return -EOVERFLOW;
+-
+ if (!list_empty(&set->bindings) && set->flags & NFT_SET_ANONYMOUS)
+ return -EBUSY;
+
+@@ -3420,10 +3431,12 @@ int nf_tables_bind_set(const struct nft_
+ 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;
+ }
+@@ -3448,7 +3461,7 @@ void nf_tables_activate_set(const struct
+ if (set->flags & NFT_SET_ANONYMOUS)
+ nft_clear(ctx->net, set);
+
+- set->use++;
++ nft_use_inc_restore(&set->use);
+ }
+ EXPORT_SYMBOL_GPL(nf_tables_activate_set);
+
+@@ -3464,17 +3477,17 @@ void nf_tables_deactivate_set(const stru
+ else
+ list_del_rcu(&binding->list);
+
+- set->use--;
++ nft_use_dec(&set->use);
+ break;
+ case NFT_TRANS_PREPARE:
+ if (set->flags & NFT_SET_ANONYMOUS)
+ nft_deactivate_next(ctx->net, set);
+
+- set->use--;
++ nft_use_dec(&set->use);
+ return;
+ case NFT_TRANS_ABORT:
+ case NFT_TRANS_RELEASE:
+- set->use--;
++ nft_use_dec(&set->use);
+ /* fall through */
+ default:
+ nf_tables_unbind_set(ctx, set, binding,
+@@ -3947,7 +3960,7 @@ void nft_set_elem_destroy(const struct n
+ if (destroy_expr && nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
+ nf_tables_expr_destroy(NULL, 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);
+@@ -4090,8 +4103,16 @@ static int nft_add_set_elem(struct nft_c
+ set->objtype, genmask);
+ if (IS_ERR(obj)) {
+ err = PTR_ERR(obj);
++ obj = NULL;
+ goto err2;
+ }
++
++ if (!nft_use_inc(&obj->use)) {
++ err = -EMFILE;
++ obj = NULL;
++ goto err2;
++ }
++
+ nft_set_ext_add(&tmpl, NFT_SET_EXT_OBJREF);
+ }
+
+@@ -4150,10 +4171,8 @@ static int nft_add_set_elem(struct nft_c
+ udata->len = ulen - 1;
+ nla_memcpy(&udata->data, nla[NFTA_SET_ELEM_USERDATA], ulen);
+ }
+- if (obj) {
++ if (obj)
+ *nft_set_ext_obj(ext) = obj;
+- obj->use++;
+- }
+
+ trans = nft_trans_elem_alloc(ctx, NFT_MSG_NEWSETELEM, set);
+ if (trans == NULL)
+@@ -4199,13 +4218,14 @@ err6:
+ err5:
+ kfree(trans);
+ err4:
+- if (obj)
+- obj->use--;
+ kfree(elem.priv);
+ err3:
+ if (nla[NFTA_SET_ELEM_DATA] != NULL)
+ nft_data_release(&elem.data.val, desc.type);
+ err2:
++ if (obj)
++ nft_use_dec_restore(&obj->use);
++
+ nft_data_release(&elem.key.val, NFT_DATA_VALUE);
+ err1:
+ return err;
+@@ -4266,11 +4286,14 @@ static int nf_tables_newsetelem(struct n
+ */
+ void nft_data_hold(const struct nft_data *data, enum nft_data_types type)
+ {
++ struct nft_chain *chain;
++
+ if (type == NFT_DATA_VERDICT) {
+ switch (data->verdict.code) {
+ case NFT_JUMP:
+ case NFT_GOTO:
+- data->verdict.chain->use++;
++ chain = data->verdict.chain;
++ nft_use_inc_restore(&chain->use);
+ break;
+ }
+ }
+@@ -4285,7 +4308,7 @@ static void nft_set_elem_activate(const
+ 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_set_elem_deactivate(const struct net *net,
+@@ -4297,7 +4320,7 @@ static void nft_set_elem_deactivate(cons
+ 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,
+@@ -4672,9 +4695,14 @@ static int nf_tables_newobj(struct net *
+
+ nft_ctx_init(&ctx, net, skb, nlh, afi, table, NULL, nla);
+
++ if (!nft_use_inc(&table->use))
++ return -EMFILE;
++
+ type = nft_obj_type_get(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)) {
+@@ -4693,7 +4721,7 @@ static int nf_tables_newobj(struct net *
+ goto err3;
+
+ list_add_tail_rcu(&obj->list, &table->objects);
+- table->use++;
++
+ return 0;
+ err3:
+ kfree(obj->name);
+@@ -4703,6 +4731,9 @@ err2:
+ kfree(obj);
+ err1:
+ module_put(type->owner);
++err_type:
++ nft_use_dec_restore(&table->use);
++
+ return err;
+ }
+
+@@ -5304,7 +5335,7 @@ static int nf_tables_commit(struct net *
+ */
+ if (nft_trans_set(trans)->flags & NFT_SET_ANONYMOUS &&
+ !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);
+@@ -5418,7 +5449,7 @@ static int nf_tables_abort(struct net *n
+ kfree(nft_trans_chain_name(trans));
+ nft_trans_destroy(trans);
+ } else {
+- trans->ctx.table->use--;
++ nft_use_dec_restore(&trans->ctx.table->use);
+ list_del_rcu(&trans->ctx.chain->list);
+ nf_tables_unregister_hooks(trans->ctx.net,
+ trans->ctx.table,
+@@ -5427,25 +5458,25 @@ static int nf_tables_abort(struct net *n
+ }
+ break;
+ case NFT_MSG_DELCHAIN:
+- trans->ctx.table->use++;
++ nft_use_inc_restore(&trans->ctx.table->use);
+ nft_clear(trans->ctx.net, trans->ctx.chain);
+ nft_trans_destroy(trans);
+ break;
+ case NFT_MSG_NEWRULE:
+- 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),
+ NFT_TRANS_ABORT);
+ break;
+ case NFT_MSG_DELRULE:
+- 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));
+ nft_trans_destroy(trans);
+ break;
+ case NFT_MSG_NEWSET:
+- trans->ctx.table->use--;
++ nft_use_dec_restore(&trans->ctx.table->use);
+ if (nft_trans_set_bound(trans)) {
+ nft_trans_destroy(trans);
+ break;
+@@ -5453,7 +5484,7 @@ static int nf_tables_abort(struct net *n
+ list_del_rcu(&nft_trans_set(trans)->list);
+ break;
+ case NFT_MSG_DELSET:
+- trans->ctx.table->use++;
++ nft_use_inc_restore(&trans->ctx.table->use);
+ nft_clear(trans->ctx.net, nft_trans_set(trans));
+ nft_trans_destroy(trans);
+ break;
+@@ -5477,11 +5508,11 @@ static int nf_tables_abort(struct net *n
+ nft_trans_destroy(trans);
+ break;
+ case NFT_MSG_NEWOBJ:
+- trans->ctx.table->use--;
++ nft_use_dec_restore(&trans->ctx.table->use);
+ list_del_rcu(&nft_trans_obj(trans)->list);
+ break;
+ case NFT_MSG_DELOBJ:
+- 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;
+@@ -5882,8 +5913,9 @@ static int nft_verdict_init(const struct
+ return PTR_ERR(chain);
+ if (nft_is_base_chain(chain))
+ return -EOPNOTSUPP;
++ if (!nft_use_inc(&chain->use))
++ return -EMFILE;
+
+- chain->use++;
+ data->verdict.chain = chain;
+ break;
+ }
+@@ -5895,10 +5927,13 @@ static int nft_verdict_init(const struct
+
+ static void nft_verdict_uninit(const struct nft_data *data)
+ {
++ struct nft_chain *chain;
++
+ switch (data->verdict.code) {
+ case NFT_JUMP:
+ case NFT_GOTO:
+- data->verdict.chain->use--;
++ chain = data->verdict.chain;
++ nft_use_dec(&chain->use);
+ break;
+ }
+ }
+@@ -6059,11 +6094,11 @@ int __nft_release_basechain(struct nft_c
+ ctx->afi->nops);
+ 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);
+ }
+ list_del(&ctx->chain->list);
+- ctx->table->use--;
++ nft_use_dec(&ctx->table->use);
+ nf_tables_chain_destroy(ctx->chain);
+
+ return 0;
+@@ -6093,23 +6128,23 @@ static void __nft_release_afinfo(struct
+ 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(set, ns, &table->sets, list) {
+ list_del(&set->list);
+- table->use--;
++ nft_use_dec(&table->use);
+ nft_set_destroy(set);
+ }
+ list_for_each_entry_safe(obj, ne, &table->objects, list) {
+ list_del(&obj->list);
+- table->use--;
++ nft_use_dec(&table->use);
+ nft_obj_destroy(obj);
+ }
+ list_for_each_entry_safe(chain, nc, &table->chains, list) {
+ list_del(&chain->list);
+- table->use--;
++ nft_use_dec(&table->use);
+ nf_tables_chain_destroy(chain);
+ }
+ list_del(&table->list);
+--- a/net/netfilter/nft_objref.c
++++ b/net/netfilter/nft_objref.c
+@@ -43,8 +43,10 @@ static int nft_objref_init(const struct
+ if (IS_ERR(obj))
+ return -ENOENT;
+
++ if (!nft_use_inc(&obj->use))
++ return -EMFILE;
++
+ nft_objref_priv(expr) = obj;
+- obj->use++;
+
+ return 0;
+ }
+@@ -73,7 +75,7 @@ static void nft_objref_deactivate(const
+ if (phase == NFT_TRANS_COMMIT)
+ return;
+
+- obj->use--;
++ nft_use_dec(&obj->use);
+ }
+
+ static void nft_objref_activate(const struct nft_ctx *ctx,
+@@ -81,7 +83,7 @@ static void nft_objref_activate(const st
+ {
+ struct nft_object *obj = nft_objref_priv(expr);
+
+- obj->use++;
++ nft_use_inc_restore(&obj->use);
+ }
+
+ static struct nft_expr_type nft_objref_type;
projects / thirdparty / kernel / stable-queue.git / commitdiff
