netfilter: nfnetlink_cthelper: hit EBUSY on updates if size mismatches

The private helper data size cannot be updated. However, updates that
contain NFCTH_PRIV_DATA_LEN might bogusly hit EBUSY even if the size is
the same.

Fixes: 12f7a50533 ("netfilter: add user-space connection tracking helper infrastructure")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2021-05-28 13:45:16 +02:00
parent 1710eb913b
commit 8971ee8b08

View File

@ -380,10 +380,14 @@ static int
nfnl_cthelper_update(const struct nlattr * const tb[],
struct nf_conntrack_helper *helper)
{
u32 size;
int ret;
if (tb[NFCTH_PRIV_DATA_LEN])
return -EBUSY;
if (tb[NFCTH_PRIV_DATA_LEN]) {
size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
if (size != helper->data_len)
return -EBUSY;
}
if (tb[NFCTH_POLICY]) {
ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);