[PATCH AUTOSEL 3.18 53/98] rtnl: don't account unused struct ifla_port_vsi in rtnl_port_size

Sasha Levin
2018-10-25T14:18:08Z

From: Daniel Borkmann <daniel@iogearbox.net>

[ Upstream commit 025331df34f6722f86b467cb13a69326444ab1bc ]

When allocating rtnl dump messages, struct ifla_port_vsi is never dumped,
so we can save header plus payload in rtnl_port_size(). Infact, attribute
IFLA_PORT_VSI_TYPE and struct ifla_port_vsi are not used anywhere in
the kernel. We only need to keep the nla policy should applications in
user space be filling this out. Same NLA_BINARY issue exists as was fixed
in 364d5716a7ad ("rtnetlink: ifla_vf_policy: fix misuses of NLA_BINARY")
and others, but then again IFLA_PORT_VSI_TYPE is not used anywhere, so
just add a comment that it's unused.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/rtnetlink.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 51301ad3c2d9..cd09f85ba8d6 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -817,8 +817,6 @@ static size_t rtnl_port_size(const struct net_device *dev,
{
size_t port_size = nla_total_size(4) /* PORT_VF */
+ nla_total_size(PORT_PROFILE_MAX) /* PORT_PROFILE */
- + nla_total_size(sizeof(struct ifla_port_vsi))
- /* PORT_VSI_TYPE */
+ nla_total_size(PORT_UUID_MAX) /* PORT_INSTANCE_UUID */
+ nla_total_size(PORT_UUID_MAX) /* PORT_HOST_UUID */
+ nla_total_size(1) /* PROT_VDP_REQUEST */
@@ -1231,14 +1229,19 @@ static const struct nla_policy ifla_port_policy[IFLA_PORT_MAX+1] = {
[IFLA_PORT_VF] = { .type = NLA_U32 },
[IFLA_PORT_PROFILE] = { .type = NLA_STRING,
.len = PORT_PROFILE_MAX },
- [IFLA_PORT_VSI_TYPE] = { .type = NLA_BINARY,
- .len = sizeof(struct ifla_port_vsi)},
[IFLA_PORT_INSTANCE_UUID] = { .type = NLA_BINARY,
.len = PORT_UUID_MAX },
[IFLA_PORT_HOST_UUID] = { .type = NLA_STRING,
.len = PORT_UUID_MAX },
[IFLA_PORT_REQUEST] = { .type = NLA_U8, },
[IFLA_PORT_RESPONSE] = { .type = NLA_U16, },
+
+ /* Unused, but we need to keep it here since user space could
+ * fill it. It's also broken with regard to NLA_BINARY use in
+ * combination with structs.
+ */
+ [IFLA_PORT_VSI_TYPE] = { .type = NLA_BINARY,
+ .len = sizeof(struct ifla_port_vsi) },
};

static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
--
2.17.1