Re: [PATCH net] net: netfilter: Fix use-after-free in get_info()

Dong Chenchen [off-list ref] wrote:

quoted

 net/netfilter/x_tables.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index

da5d929c7c85..359c880ecb07 100644

--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c

@@ -1239,6 +1239,7 @@ struct xt_table *xt_find_table_lock(struct net *net,

u_int8_t af,

quoted

 	struct module *owner = NULL;
 	struct xt_template *tmpl;
 	struct xt_table *t;
+	int err = -ENOENT;

 	mutex_lock(&xt[af].mutex);
 	list_for_each_entry(t, &xt_net->tables[af], list) @@ -1247,8 +1248,6

@@ struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,

 	/* Table doesn't exist in this netns, check larval list */
 	list_for_each_entry(tmpl, &xt_templates[af], list) {
-		int err;
-
 		if (strcmp(tmpl->name, name))
 			continue;
 		if (!try_module_get(tmpl->me))

@@ -1267,6 +1266,9 @@ struct xt_table *xt_find_table_lock(struct net *net,

u_int8_t af,

quoted

 		break;
 	}

+	if (err < 0)
+		goto out;
+
 	/* and once again: */
 	list_for_each_entry(t, &xt_net->tables[af], list)
 		if (strcmp(t->name, name) == 0)

Proabably also:

-  		if (strcmp(t->name, name) == 0)
+               if (strcmp(t->name, name) == 0 && owner == t->me)

Thank you very much for your suggestions!
V2 will be sent.