netfilter: ctnetlink: memleak in filter initialization error path

Release the filter object in case of error.

Fixes: cb8aa9a3affb ("netfilter: ctnetlink: add kernel side filtering for dump")
Reported-by: syzbot+38b8b548a851a01793c5@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index d7bd8b1..832eabe 100644 (file)
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -939,7 +939,8 @@ ctnetlink_alloc_filter(const struct nlattr * const cda[], u8 family)
                        filter->mark.mask = 0xffffffff;
                }
        } else if (cda[CTA_MARK_MASK]) {
-               return ERR_PTR(-EINVAL);
+               err = -EINVAL;
+               goto err_filter;
        }
 #endif
        if (!cda[CTA_FILTER])
@@ -947,15 +948,17 @@ ctnetlink_alloc_filter(const struct nlattr * const cda[], u8 family)
 
        err = ctnetlink_parse_zone(cda[CTA_ZONE], &filter->zone);
        if (err < 0)
-               return ERR_PTR(err);
+               goto err_filter;
 
        err = ctnetlink_parse_filter(cda[CTA_FILTER], filter);
        if (err < 0)
-               return ERR_PTR(err);
+               goto err_filter;
 
        if (filter->orig_flags) {
-               if (!cda[CTA_TUPLE_ORIG])
-                       return ERR_PTR(-EINVAL);
+               if (!cda[CTA_TUPLE_ORIG]) {
+                       err = -EINVAL;
+                       goto err_filter;
+               }
 
                err = ctnetlink_parse_tuple_filter(cda, &filter->orig,
                                                   CTA_TUPLE_ORIG,
@@ -963,23 +966,32 @@ ctnetlink_alloc_filter(const struct nlattr * const cda[], u8 family)
                                                   &filter->zone,
                                                   filter->orig_flags);
                if (err < 0)
-                       return ERR_PTR(err);
+                       goto err_filter;
        }
 
        if (filter->reply_flags) {
-               if (!cda[CTA_TUPLE_REPLY])
-                       return ERR_PTR(-EINVAL);
+               if (!cda[CTA_TUPLE_REPLY]) {
+                       err = -EINVAL;
+                       goto err_filter;
+               }
 
                err = ctnetlink_parse_tuple_filter(cda, &filter->reply,
                                                   CTA_TUPLE_REPLY,
                                                   filter->family,
                                                   &filter->zone,
                                                   filter->orig_flags);
-               if (err < 0)
-                       return ERR_PTR(err);
+               if (err < 0) {
+                       err = -EINVAL;
+                       goto err_filter;
+               }
        }
 
        return filter;
+
+err_filter:
+       kfree(filter);
+
+       return ERR_PTR(err);
 }
 
 static bool ctnetlink_needs_filter(u8 family, const struct nlattr * const *cda)