From: Florian Westphal <fw@xxxxxxxxx>
Userspace should not abuse the kernel to store large amounts of data,
reject requests larger than the private area can accommodate.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nfnetlink_cthelper.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nfnetlink_cthelper.c b/net/netfilter/nfnetlink_cthelper.c
index 9a50bf93dd16..eef7120e1f74 100644
--- a/net/netfilter/nfnetlink_cthelper.c
+++ b/net/netfilter/nfnetlink_cthelper.c
@@ -104,7 +104,7 @@ nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
if (help->helper->data_len == 0)
return -EINVAL;
- memcpy(help->data, nla_data(attr), help->helper->data_len);
+ nla_memcpy(help->data, nla_data(attr), sizeof(help->data));
return 0;
}
@@ -216,6 +216,7 @@ nfnl_cthelper_create(const struct nlattr * const tb[],
{
struct nf_conntrack_helper *helper;
struct nfnl_cthelper *nfcth;
+ unsigned int size;
int ret;
if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
@@ -231,7 +232,12 @@ nfnl_cthelper_create(const struct nlattr * const tb[],
goto err1;
strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
- helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
+ size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
+ if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
+ ret = -ENOMEM;
+ goto err2;
+ }
+
helper->flags |= NF_CT_HELPER_F_USERSPACE;
memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
--
2.1.4
--
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