From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/netfilter/nf_tables.h | 31 ++++++-
net/netfilter/nf_tables_api.c | 166 +++++++++++++++++++++++---------------
net/netfilter/nft_flow_offload.c | 6 -
net/netfilter/nft_objref.c | 8 +
4 files changed, 140 insertions(+), 71 deletions(-)
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1013,6 +1013,29 @@ 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
*
@@ -1082,8 +1105,8 @@ 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;
/* runtime data below here */
const struct nft_object_ops *ops ____cacheline_aligned;
@@ -1185,8 +1208,8 @@ struct nft_flowtable {
int hooknum;
int priority;
int ops_len;
- u32 genmask:2,
- use:30;
+ u32 genmask:2;
+ u32 use;
u64 handle;
/* runtime data below here */
struct nf_hook_ops *ops ____cacheline_aligned;
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -282,7 +282,7 @@ static int nft_delchain(struct nft_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;
@@ -323,7 +323,7 @@ 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;
@@ -412,7 +412,7 @@ 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;
}
@@ -444,7 +444,7 @@ 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;
}
@@ -478,7 +478,7 @@ static int nft_delflowtable(struct nft_c
return err;
nft_deactivate_next(ctx->net, flowtable);
- ctx->table->use--;
+ nft_use_dec(&ctx->table->use);
return err;
}
@@ -1715,9 +1715,6 @@ static int nf_tables_addchain(struct nft
struct nft_rule **rules;
int err;
- if (table->use == UINT_MAX)
- return -EOVERFLOW;
-
if (nla[NFTA_CHAIN_HOOK]) {
struct nft_chain_hook hook;
struct nf_hook_ops *ops;
@@ -1794,6 +1791,11 @@ static int nf_tables_addchain(struct nft
if (err < 0)
goto err1;
+ if (!nft_use_inc(&table->use)) {
+ err = -EMFILE;
+ goto err_use;
+ }
+
err = rhltable_insert_key(&table->chains_ht, chain->name,
&chain->rhlhead, nft_chain_ht_params);
if (err)
@@ -1811,11 +1813,12 @@ static int nf_tables_addchain(struct nft
if (nft_is_base_chain(chain))
nft_trans_chain_policy(trans) = policy;
- table->use++;
list_add_tail_rcu(&chain->list, &table->chains);
return 0;
err2:
+ nft_use_dec_restore(&table->use);
+err_use:
nf_tables_unregister_hook(net, table, chain);
err1:
nf_tables_chain_destroy(ctx);
@@ -2831,9 +2834,6 @@ static int nf_tables_newrule(struct net
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);
@@ -2915,16 +2915,21 @@ 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);
@@ -2932,7 +2937,7 @@ static int nf_tables_newrule(struct net
trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
if (!trans) {
err = -ENOMEM;
- goto err2;
+ goto err_destroy_flow_rule;
}
if (nlh->nlmsg_flags & NLM_F_APPEND) {
@@ -2948,7 +2953,6 @@ static int nf_tables_newrule(struct net
}
}
kvfree(info);
- chain->use++;
if (nft_net->validate_state == NFT_VALIDATE_DO)
return nft_table_validate(net, table);
@@ -2962,6 +2966,9 @@ static int nf_tables_newrule(struct net
}
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);
@@ -3775,10 +3782,15 @@ 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);
@@ -3825,7 +3837,7 @@ static int nf_tables_newset(struct net *
goto err4;
list_add_tail_rcu(&set->list, &table->sets);
- table->use++;
+
return 0;
err4:
@@ -3834,6 +3846,8 @@ err3:
kfree(set->name);
err2:
kvfree(set);
+err_alloc:
+ nft_use_dec_restore(&table->use);
err1:
module_put(to_set_type(ops)->owner);
return err;
@@ -3920,9 +3934,6 @@ 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) && nft_set_is_anonymous(set))
return -EBUSY;
@@ -3947,10 +3958,12 @@ 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;
}
@@ -3974,7 +3987,7 @@ void nf_tables_activate_set(const struct
if (nft_set_is_anonymous(set))
nft_clear(ctx->net, set);
- set->use++;
+ nft_use_inc_restore(&set->use);
}
EXPORT_SYMBOL_GPL(nf_tables_activate_set);
@@ -3990,17 +4003,17 @@ 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 (nft_set_is_anonymous(set))
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,
@@ -4585,7 +4598,7 @@ void nft_set_elem_destroy(const struct n
}
}
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);
@@ -4706,8 +4719,16 @@ 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);
}
@@ -4772,10 +4793,8 @@ 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)
@@ -4821,13 +4840,14 @@ 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;
@@ -4887,11 +4907,14 @@ 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;
}
}
@@ -4906,7 +4929,7 @@ 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,
@@ -4918,7 +4941,7 @@ 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,
@@ -5375,9 +5398,14 @@ static int nf_tables_newobj(struct net *
nft_ctx_init(&ctx, net, skb, 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)) {
@@ -5403,7 +5431,7 @@ static int nf_tables_newobj(struct net *
goto err4;
list_add_tail_rcu(&obj->list, &table->objects);
- table->use++;
+
return 0;
err4:
/* queued in transaction log */
@@ -5417,6 +5445,9 @@ err2:
kfree(obj);
err1:
module_put(type->owner);
+err_type:
+ nft_use_dec_restore(&table->use);
+
return err;
}
@@ -5761,7 +5792,7 @@ void nf_tables_deactivate_flowtable(cons
case NFT_TRANS_PREPARE:
case NFT_TRANS_ABORT:
case NFT_TRANS_RELEASE:
- flowtable->use--;
+ nft_use_dec(&flowtable->use);
/* fall through */
default:
return;
@@ -5967,9 +5998,14 @@ static int nf_tables_newflowtable(struct
nft_ctx_init(&ctx, net, skb, nlh, family, table, NULL, nla);
+ if (!nft_use_inc(&table->use))
+ return -EMFILE;
+
flowtable = kzalloc(sizeof(*flowtable), GFP_KERNEL);
- if (!flowtable)
- return -ENOMEM;
+ if (!flowtable) {
+ err = -ENOMEM;
+ goto flowtable_alloc;
+ }
flowtable->table = table;
flowtable->handle = nf_tables_alloc_handle(table);
@@ -6023,7 +6059,6 @@ static int nf_tables_newflowtable(struct
goto err6;
list_add_tail_rcu(&flowtable->list, &table->flowtables);
- table->use++;
return 0;
err6:
@@ -6041,6 +6076,9 @@ err2:
kfree(flowtable->name);
err1:
kfree(flowtable);
+flowtable_alloc:
+ nft_use_dec_restore(&table->use);
+
return err;
}
@@ -7035,7 +7073,7 @@ static int nf_tables_commit(struct net *
*/
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);
@@ -7188,7 +7226,7 @@ static int __nf_tables_abort(struct net
kfree(nft_trans_chain_name(trans));
nft_trans_destroy(trans);
} else {
- 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,
@@ -7196,25 +7234,25 @@ static int __nf_tables_abort(struct net
}
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;
@@ -7222,7 +7260,7 @@ static int __nf_tables_abort(struct net
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;
@@ -7249,23 +7287,23 @@ static int __nf_tables_abort(struct net
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:
- 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;
case NFT_MSG_NEWFLOWTABLE:
- 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));
break;
case NFT_MSG_DELFLOWTABLE:
- 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);
break;
@@ -7685,8 +7723,9 @@ 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;
}
@@ -7698,10 +7737,13 @@ 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;
}
}
@@ -7855,11 +7897,11 @@ int __nft_release_basechain(struct nft_c
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;
@@ -7896,29 +7938,29 @@ static void __nft_release_table(struct n
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);
nft_set_destroy(set);
}
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);
}
list_del(&table->list);
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -171,8 +171,10 @@ static int nft_flow_offload_init(const s
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);
}
@@ -191,7 +193,7 @@ static void nft_flow_offload_activate(co
{
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,
--- a/net/netfilter/nft_objref.c
+++ b/net/netfilter/nft_objref.c
@@ -41,8 +41,10 @@ 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;
}
@@ -71,7 +73,7 @@ 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,
@@ -79,7 +81,7 @@ 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;
