netfilter: nft_masq: register/unregister notifiers on module init/exit

We have to register the notifiers in the masquerade expression from
the the module _init and _exit path.

This fixes crashes when removing the masquerade rule with no
ipt_MASQUERADE support in place (which was masking the problem).

Fixes: 9ba1f72 ("netfilter: nf_tables: add new nft_masq expression")
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 22 insertions, 46 deletions

diff --git a/net/ipv4/netfilter/nft_masq_ipv4.c b/net/ipv4/netfilter/nft_masq_ipv4.c
index 6ea1d207b6a5..1c636d6b5b50 100644
--- a/net/ipv4/netfilter/nft_masq_ipv4.c
+++ b/net/ipv4/netfilter/nft_masq_ipv4.c
@@ -32,33 +32,12 @@ static void nft_masq_ipv4_eval(const struct nft_expr *expr,
         data[NFT_REG_VERDICT].verdict = verdict;
 }
 
-static int nft_masq_ipv4_init(const struct nft_ctx *ctx,
-                              const struct nft_expr *expr,
-                              const struct nlattr * const tb[])
-{
-        int err;
-
-        err = nft_masq_init(ctx, expr, tb);
-        if (err < 0)
-                return err;
-
-        nf_nat_masquerade_ipv4_register_notifier();
-        return 0;
-}
-
-static void nft_masq_ipv4_destroy(const struct nft_ctx *ctx,
-                                  const struct nft_expr *expr)
-{
-        nf_nat_masquerade_ipv4_unregister_notifier();
-}
-
 static struct nft_expr_type nft_masq_ipv4_type;
 static const struct nft_expr_ops nft_masq_ipv4_ops = {
         .type           = &nft_masq_ipv4_type,
         .size           = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
         .eval           = nft_masq_ipv4_eval,
-        .init           = nft_masq_ipv4_init,
-        .destroy        = nft_masq_ipv4_destroy,
+        .init           = nft_masq_init,
         .dump           = nft_masq_dump,
 };
 
@@ -73,12 +52,21 @@ static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
 
 static int __init nft_masq_ipv4_module_init(void)
 {
-        return nft_register_expr(&nft_masq_ipv4_type);
+        int ret;
+
+        ret = nft_register_expr(&nft_masq_ipv4_type);
+        if (ret < 0)
+                return ret;
+
+        nf_nat_masquerade_ipv4_register_notifier();
+
+        return ret;
 }
 
 static void __exit nft_masq_ipv4_module_exit(void)
 {
         nft_unregister_expr(&nft_masq_ipv4_type);
+        nf_nat_masquerade_ipv4_unregister_notifier();
 }
 
 module_init(nft_masq_ipv4_module_init);
diff --git a/net/ipv6/netfilter/nft_masq_ipv6.c b/net/ipv6/netfilter/nft_masq_ipv6.c
index 4e51334ef6b7..556262f40761 100644
--- a/net/ipv6/netfilter/nft_masq_ipv6.c
+++ b/net/ipv6/netfilter/nft_masq_ipv6.c
@@ -32,33 +32,12 @@ static void nft_masq_ipv6_eval(const struct nft_expr *expr,
         data[NFT_REG_VERDICT].verdict = verdict;
 }
 
-static int nft_masq_ipv6_init(const struct nft_ctx *ctx,
-                              const struct nft_expr *expr,
-                              const struct nlattr * const tb[])
-{
-        int err;
-
-        err = nft_masq_init(ctx, expr, tb);
-        if (err < 0)
-                return err;
-
-        nf_nat_masquerade_ipv6_register_notifier();
-        return 0;
-}
-
-static void nft_masq_ipv6_destroy(const struct nft_ctx *ctx,
-                                  const struct nft_expr *expr)
-{
-        nf_nat_masquerade_ipv6_unregister_notifier();
-}
-
 static struct nft_expr_type nft_masq_ipv6_type;
 static const struct nft_expr_ops nft_masq_ipv6_ops = {
         .type           = &nft_masq_ipv6_type,
         .size           = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
         .eval           = nft_masq_ipv6_eval,
-        .init           = nft_masq_ipv6_init,
-        .destroy        = nft_masq_ipv6_destroy,
+        .init           = nft_masq_init,
         .dump           = nft_masq_dump,
 };
 
@@ -73,12 +52,21 @@ static struct nft_expr_type nft_masq_ipv6_type __read_mostly = {
 
 static int __init nft_masq_ipv6_module_init(void)
 {
-        return nft_register_expr(&nft_masq_ipv6_type);
+        int ret;
+
+        ret = nft_register_expr(&nft_masq_ipv6_type);
+        if (ret < 0)
+                return ret;
+
+        nf_nat_masquerade_ipv6_register_notifier();
+
+        return ret;
 }
 
 static void __exit nft_masq_ipv6_module_exit(void)
 {
         nft_unregister_expr(&nft_masq_ipv6_type);
+        nf_nat_masquerade_ipv6_unregister_notifier();
 }
 
 module_init(nft_masq_ipv6_module_init);