--- /dev/null
+From dd94fef9b549529ccbbb500b6273d4936b376d61 Mon Sep 17 00:00:00 2001
+From: Pablo Neira Ayuso <pablo@netfilter.org>
+Date: Wed, 13 Feb 2019 13:18:36 +0100
+Subject: netfilter: nft_compat: use .release_ops and remove list of extension
+
+[ Upstream commit b8e204006340b7aaf32bd2b9806c692f6e0cb38a ]
+
+Add .release_ops, that is called in case of error at a later stage in
+the expression initialization path, ie. .select_ops() has been already
+set up operations and that needs to be undone. This allows us to unwind
+.select_ops from the error path, ie. release the dynamic operations for
+this extension.
+
+Moreover, allocate one single operation instead of recycling them, this
+comes at the cost of consuming a bit more memory per rule, but it
+simplifies the infrastructure.
+
+Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ include/net/netfilter/nf_tables.h | 3 +
+ net/netfilter/nf_tables_api.c | 7 +-
+ net/netfilter/nft_compat.c | 281 ++++++------------------------
+ 3 files changed, 64 insertions(+), 227 deletions(-)
+
+diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
+index 3d58acf94dd2..0612439909dc 100644
+--- a/include/net/netfilter/nf_tables.h
++++ b/include/net/netfilter/nf_tables.h
+@@ -691,10 +691,12 @@ static inline void nft_set_gc_batch_add(struct nft_set_gc_batch *gcb,
+ gcb->elems[gcb->head.cnt++] = elem;
+ }
+
++struct nft_expr_ops;
+ /**
+ * struct nft_expr_type - nf_tables expression type
+ *
+ * @select_ops: function to select nft_expr_ops
++ * @release_ops: release nft_expr_ops
+ * @ops: default ops, used when no select_ops functions is present
+ * @list: used internally
+ * @name: Identifier
+@@ -707,6 +709,7 @@ static inline void nft_set_gc_batch_add(struct nft_set_gc_batch *gcb,
+ struct nft_expr_type {
+ const struct nft_expr_ops *(*select_ops)(const struct nft_ctx *,
+ const struct nlattr * const tb[]);
++ void (*release_ops)(const struct nft_expr_ops *ops);
+ const struct nft_expr_ops *ops;
+ struct list_head list;
+ const char *name;
+diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
+index e1724f9d8b9d..dc3670f2860e 100644
+--- a/net/netfilter/nf_tables_api.c
++++ b/net/netfilter/nf_tables_api.c
+@@ -2129,6 +2129,7 @@ struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
+ {
+ struct nft_expr_info info;
+ struct nft_expr *expr;
++ struct module *owner;
+ int err;
+
+ err = nf_tables_expr_parse(ctx, nla, &info);
+@@ -2148,7 +2149,11 @@ struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
+ err3:
+ kfree(expr);
+ err2:
+- module_put(info.ops->type->owner);
++ owner = info.ops->type->owner;
++ if (info.ops->type->release_ops)
++ info.ops->type->release_ops(info.ops);
++
++ module_put(owner);
+ err1:
+ return ERR_PTR(err);
+ }
+diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
+index 0a4bad55a8aa..469f9da5073b 100644
+--- a/net/netfilter/nft_compat.c
++++ b/net/netfilter/nft_compat.c
+@@ -22,23 +22,6 @@
+ #include <linux/netfilter_bridge/ebtables.h>
+ #include <linux/netfilter_arp/arp_tables.h>
+ #include <net/netfilter/nf_tables.h>
+-#include <net/netns/generic.h>
+-
+-struct nft_xt {
+- struct list_head head;
+- struct nft_expr_ops ops;
+- refcount_t refcnt;
+-
+- /* used only when transaction mutex is locked */
+- unsigned int listcnt;
+-
+- /* Unlike other expressions, ops doesn't have static storage duration.
+- * nft core assumes they do. We use kfree_rcu so that nft core can
+- * can check expr->ops->size even after nft_compat->destroy() frees
+- * the nft_xt struct that holds the ops structure.
+- */
+- struct rcu_head rcu_head;
+-};
+
+ /* Used for matches where *info is larger than X byte */
+ #define NFT_MATCH_LARGE_THRESH 192
+@@ -47,46 +30,6 @@ struct nft_xt_match_priv {
+ void *info;
+ };
+
+-struct nft_compat_net {
+- struct list_head nft_target_list;
+- struct list_head nft_match_list;
+-};
+-
+-static unsigned int nft_compat_net_id __read_mostly;
+-static struct nft_expr_type nft_match_type;
+-static struct nft_expr_type nft_target_type;
+-
+-static struct nft_compat_net *nft_compat_pernet(struct net *net)
+-{
+- return net_generic(net, nft_compat_net_id);
+-}
+-
+-static void nft_xt_get(struct nft_xt *xt)
+-{
+- /* refcount_inc() warns on 0 -> 1 transition, but we can't
+- * init the reference count to 1 in .select_ops -- we can't
+- * undo such an increase when another expression inside the same
+- * rule fails afterwards.
+- */
+- if (xt->listcnt == 0)
+- refcount_set(&xt->refcnt, 1);
+- else
+- refcount_inc(&xt->refcnt);
+-
+- xt->listcnt++;
+-}
+-
+-static bool nft_xt_put(struct nft_xt *xt)
+-{
+- if (refcount_dec_and_test(&xt->refcnt)) {
+- WARN_ON_ONCE(!list_empty(&xt->head));
+- kfree_rcu(xt, rcu_head);
+- return true;
+- }
+-
+- return false;
+-}
+-
+ static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
+ const char *tablename)
+ {
+@@ -281,7 +224,6 @@ nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+ struct xt_target *target = expr->ops->data;
+ struct xt_tgchk_param par;
+ size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
+- struct nft_xt *nft_xt;
+ u16 proto = 0;
+ bool inv = false;
+ union nft_entry e = {};
+@@ -305,8 +247,6 @@ nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+ if (!target->target)
+ return -EINVAL;
+
+- nft_xt = container_of(expr->ops, struct nft_xt, ops);
+- nft_xt_get(nft_xt);
+ return 0;
+ }
+
+@@ -325,8 +265,8 @@ nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
+ if (par.target->destroy != NULL)
+ par.target->destroy(&par);
+
+- if (nft_xt_put(container_of(expr->ops, struct nft_xt, ops)))
+- module_put(me);
++ module_put(me);
++ kfree(expr->ops);
+ }
+
+ static int nft_extension_dump_info(struct sk_buff *skb, int attr,
+@@ -499,7 +439,6 @@ __nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+ struct xt_match *match = expr->ops->data;
+ struct xt_mtchk_param par;
+ size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
+- struct nft_xt *nft_xt;
+ u16 proto = 0;
+ bool inv = false;
+ union nft_entry e = {};
+@@ -515,13 +454,7 @@ __nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+
+ nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
+
+- ret = xt_check_match(&par, size, proto, inv);
+- if (ret < 0)
+- return ret;
+-
+- nft_xt = container_of(expr->ops, struct nft_xt, ops);
+- nft_xt_get(nft_xt);
+- return 0;
++ return xt_check_match(&par, size, proto, inv);
+ }
+
+ static int
+@@ -564,8 +497,8 @@ __nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr,
+ if (par.match->destroy != NULL)
+ par.match->destroy(&par);
+
+- if (nft_xt_put(container_of(expr->ops, struct nft_xt, ops)))
+- module_put(me);
++ module_put(me);
++ kfree(expr->ops);
+ }
+
+ static void
+@@ -574,18 +507,6 @@ nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
+ __nft_match_destroy(ctx, expr, nft_expr_priv(expr));
+ }
+
+-static void nft_compat_deactivate(const struct nft_ctx *ctx,
+- const struct nft_expr *expr,
+- enum nft_trans_phase phase)
+-{
+- struct nft_xt *xt = container_of(expr->ops, struct nft_xt, ops);
+-
+- if (phase == NFT_TRANS_ABORT || phase == NFT_TRANS_COMMIT) {
+- if (--xt->listcnt == 0)
+- list_del_init(&xt->head);
+- }
+-}
+-
+ static void
+ nft_match_large_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
+ {
+@@ -780,19 +701,13 @@ static const struct nfnetlink_subsystem nfnl_compat_subsys = {
+ .cb = nfnl_nft_compat_cb,
+ };
+
+-static bool nft_match_cmp(const struct xt_match *match,
+- const char *name, u32 rev, u32 family)
+-{
+- return strcmp(match->name, name) == 0 && match->revision == rev &&
+- (match->family == NFPROTO_UNSPEC || match->family == family);
+-}
++static struct nft_expr_type nft_match_type;
+
+ static const struct nft_expr_ops *
+ nft_match_select_ops(const struct nft_ctx *ctx,
+ const struct nlattr * const tb[])
+ {
+- struct nft_compat_net *cn;
+- struct nft_xt *nft_match;
++ struct nft_expr_ops *ops;
+ struct xt_match *match;
+ unsigned int matchsize;
+ char *mt_name;
+@@ -808,16 +723,6 @@ nft_match_select_ops(const struct nft_ctx *ctx,
+ rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
+ family = ctx->family;
+
+- cn = nft_compat_pernet(ctx->net);
+-
+- /* Re-use the existing match if it's already loaded. */
+- list_for_each_entry(nft_match, &cn->nft_match_list, head) {
+- struct xt_match *match = nft_match->ops.data;
+-
+- if (nft_match_cmp(match, mt_name, rev, family))
+- return &nft_match->ops;
+- }
+-
+ match = xt_request_find_match(family, mt_name, rev);
+ if (IS_ERR(match))
+ return ERR_PTR(-ENOENT);
+@@ -827,65 +732,62 @@ nft_match_select_ops(const struct nft_ctx *ctx,
+ goto err;
+ }
+
+- /* This is the first time we use this match, allocate operations */
+- nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
+- if (nft_match == NULL) {
++ ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
++ if (!ops) {
+ err = -ENOMEM;
+ goto err;
+ }
+
+- refcount_set(&nft_match->refcnt, 0);
+- nft_match->ops.type = &nft_match_type;
+- nft_match->ops.eval = nft_match_eval;
+- nft_match->ops.init = nft_match_init;
+- nft_match->ops.destroy = nft_match_destroy;
+- nft_match->ops.deactivate = nft_compat_deactivate;
+- nft_match->ops.dump = nft_match_dump;
+- nft_match->ops.validate = nft_match_validate;
+- nft_match->ops.data = match;
++ ops->type = &nft_match_type;
++ ops->eval = nft_match_eval;
++ ops->init = nft_match_init;
++ ops->destroy = nft_match_destroy;
++ ops->dump = nft_match_dump;
++ ops->validate = nft_match_validate;
++ ops->data = match;
+
+ matchsize = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
+ if (matchsize > NFT_MATCH_LARGE_THRESH) {
+ matchsize = NFT_EXPR_SIZE(sizeof(struct nft_xt_match_priv));
+
+- nft_match->ops.eval = nft_match_large_eval;
+- nft_match->ops.init = nft_match_large_init;
+- nft_match->ops.destroy = nft_match_large_destroy;
+- nft_match->ops.dump = nft_match_large_dump;
++ ops->eval = nft_match_large_eval;
++ ops->init = nft_match_large_init;
++ ops->destroy = nft_match_large_destroy;
++ ops->dump = nft_match_large_dump;
+ }
+
+- nft_match->ops.size = matchsize;
++ ops->size = matchsize;
+
+- nft_match->listcnt = 0;
+- list_add(&nft_match->head, &cn->nft_match_list);
+-
+- return &nft_match->ops;
++ return ops;
+ err:
+ module_put(match->me);
+ return ERR_PTR(err);
+ }
+
++static void nft_match_release_ops(const struct nft_expr_ops *ops)
++{
++ struct xt_match *match = ops->data;
++
++ module_put(match->me);
++ kfree(ops);
++}
++
+ static struct nft_expr_type nft_match_type __read_mostly = {
+ .name = "match",
+ .select_ops = nft_match_select_ops,
++ .release_ops = nft_match_release_ops,
+ .policy = nft_match_policy,
+ .maxattr = NFTA_MATCH_MAX,
+ .owner = THIS_MODULE,
+ };
+
+-static bool nft_target_cmp(const struct xt_target *tg,
+- const char *name, u32 rev, u32 family)
+-{
+- return strcmp(tg->name, name) == 0 && tg->revision == rev &&
+- (tg->family == NFPROTO_UNSPEC || tg->family == family);
+-}
++static struct nft_expr_type nft_target_type;
+
+ static const struct nft_expr_ops *
+ nft_target_select_ops(const struct nft_ctx *ctx,
+ const struct nlattr * const tb[])
+ {
+- struct nft_compat_net *cn;
+- struct nft_xt *nft_target;
++ struct nft_expr_ops *ops;
+ struct xt_target *target;
+ char *tg_name;
+ u32 rev, family;
+@@ -905,18 +807,6 @@ nft_target_select_ops(const struct nft_ctx *ctx,
+ strcmp(tg_name, "standard") == 0)
+ return ERR_PTR(-EINVAL);
+
+- cn = nft_compat_pernet(ctx->net);
+- /* Re-use the existing target if it's already loaded. */
+- list_for_each_entry(nft_target, &cn->nft_target_list, head) {
+- struct xt_target *target = nft_target->ops.data;
+-
+- if (!target->target)
+- continue;
+-
+- if (nft_target_cmp(target, tg_name, rev, family))
+- return &nft_target->ops;
+- }
+-
+ target = xt_request_find_target(family, tg_name, rev);
+ if (IS_ERR(target))
+ return ERR_PTR(-ENOENT);
+@@ -931,113 +821,55 @@ nft_target_select_ops(const struct nft_ctx *ctx,
+ goto err;
+ }
+
+- /* This is the first time we use this target, allocate operations */
+- nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
+- if (nft_target == NULL) {
++ ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
++ if (!ops) {
+ err = -ENOMEM;
+ goto err;
+ }
+
+- refcount_set(&nft_target->refcnt, 0);
+- nft_target->ops.type = &nft_target_type;
+- nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
+- nft_target->ops.init = nft_target_init;
+- nft_target->ops.destroy = nft_target_destroy;
+- nft_target->ops.deactivate = nft_compat_deactivate;
+- nft_target->ops.dump = nft_target_dump;
+- nft_target->ops.validate = nft_target_validate;
+- nft_target->ops.data = target;
++ ops->type = &nft_target_type;
++ ops->size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
++ ops->init = nft_target_init;
++ ops->destroy = nft_target_destroy;
++ ops->dump = nft_target_dump;
++ ops->validate = nft_target_validate;
++ ops->data = target;
+
+ if (family == NFPROTO_BRIDGE)
+- nft_target->ops.eval = nft_target_eval_bridge;
++ ops->eval = nft_target_eval_bridge;
+ else
+- nft_target->ops.eval = nft_target_eval_xt;
+-
+- nft_target->listcnt = 0;
+- list_add(&nft_target->head, &cn->nft_target_list);
++ ops->eval = nft_target_eval_xt;
+
+- return &nft_target->ops;
++ return ops;
+ err:
+ module_put(target->me);
+ return ERR_PTR(err);
+ }
+
++static void nft_target_release_ops(const struct nft_expr_ops *ops)
++{
++ struct xt_target *target = ops->data;
++
++ module_put(target->me);
++ kfree(ops);
++}
++
+ static struct nft_expr_type nft_target_type __read_mostly = {
+ .name = "target",
+ .select_ops = nft_target_select_ops,
++ .release_ops = nft_target_release_ops,
+ .policy = nft_target_policy,
+ .maxattr = NFTA_TARGET_MAX,
+ .owner = THIS_MODULE,
+ };
+
+-static int __net_init nft_compat_init_net(struct net *net)
+-{
+- struct nft_compat_net *cn = nft_compat_pernet(net);
+-
+- INIT_LIST_HEAD(&cn->nft_target_list);
+- INIT_LIST_HEAD(&cn->nft_match_list);
+-
+- return 0;
+-}
+-
+-static void __net_exit nft_compat_exit_net(struct net *net)
+-{
+- struct nft_compat_net *cn = nft_compat_pernet(net);
+- struct nft_xt *xt, *next;
+-
+- if (list_empty(&cn->nft_match_list) &&
+- list_empty(&cn->nft_target_list))
+- return;
+-
+- /* If there was an error that caused nft_xt expr to not be initialized
+- * fully and noone else requested the same expression later, the lists
+- * contain 0-refcount entries that still hold module reference.
+- *
+- * Clean them here.
+- */
+- mutex_lock(&net->nft.commit_mutex);
+- list_for_each_entry_safe(xt, next, &cn->nft_target_list, head) {
+- struct xt_target *target = xt->ops.data;
+-
+- list_del_init(&xt->head);
+-
+- if (refcount_read(&xt->refcnt))
+- continue;
+- module_put(target->me);
+- kfree(xt);
+- }
+-
+- list_for_each_entry_safe(xt, next, &cn->nft_match_list, head) {
+- struct xt_match *match = xt->ops.data;
+-
+- list_del_init(&xt->head);
+-
+- if (refcount_read(&xt->refcnt))
+- continue;
+- module_put(match->me);
+- kfree(xt);
+- }
+- mutex_unlock(&net->nft.commit_mutex);
+-}
+-
+-static struct pernet_operations nft_compat_net_ops = {
+- .init = nft_compat_init_net,
+- .exit = nft_compat_exit_net,
+- .id = &nft_compat_net_id,
+- .size = sizeof(struct nft_compat_net),
+-};
+-
+ static int __init nft_compat_module_init(void)
+ {
+ int ret;
+
+- ret = register_pernet_subsys(&nft_compat_net_ops);
+- if (ret < 0)
+- goto err_target;
+-
+ ret = nft_register_expr(&nft_match_type);
+ if (ret < 0)
+- goto err_pernet;
++ return ret;
+
+ ret = nft_register_expr(&nft_target_type);
+ if (ret < 0)
+@@ -1054,8 +886,6 @@ static int __init nft_compat_module_init(void)
+ nft_unregister_expr(&nft_target_type);
+ err_match:
+ nft_unregister_expr(&nft_match_type);
+-err_pernet:
+- unregister_pernet_subsys(&nft_compat_net_ops);
+ return ret;
+ }
+
+@@ -1064,7 +894,6 @@ static void __exit nft_compat_module_exit(void)
+ nfnetlink_subsys_unregister(&nfnl_compat_subsys);
+ nft_unregister_expr(&nft_target_type);
+ nft_unregister_expr(&nft_match_type);
+- unregister_pernet_subsys(&nft_compat_net_ops);
+ }
+
+ MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
+--
+2.19.1
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
