[PATCH 4.19 85/95] netfilter: nfnetlink_cthelper: unbreak userspace helper support

From: Greg Kroah-Hartman
Date: Mon Jun 01 2020 - 14:05:54 EST


From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>

commit 703acd70f2496537457186211c2f03e792409e68 upstream.

Restore helper data size initialization and fix memcopy of the helper
data size.

Fixes: 157ffffeb5dc ("netfilter: nfnetlink_cthelper: reject too large userspace allocation requests")
Reviewed-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/netfilter/nfnetlink_cthelper.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/netfilter/nfnetlink_cthelper.c
+++ b/net/netfilter/nfnetlink_cthelper.c
@@ -106,7 +106,7 @@ nfnl_cthelper_from_nlattr(struct nlattr
if (help->helper->data_len == 0)
return -EINVAL;

- nla_memcpy(help->data, nla_data(attr), sizeof(help->data));
+ nla_memcpy(help->data, attr, sizeof(help->data));
return 0;
}

@@ -242,6 +242,7 @@ nfnl_cthelper_create(const struct nlattr
ret = -ENOMEM;
goto err2;
}
+ helper->data_len = size;

helper->flags |= NF_CT_HELPER_F_USERSPACE;
memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));