From: Daniel Borkmann <daniel@iogearbox.net>
Date: Mon, 27 Nov 2023 20:05:33 +0000 (+0100)
Subject: netkit: Reject IFLA_NETKIT_PEER_INFO in netkit_change_link
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0bad281d0ecdf8391b0f42678b663336e7c3ceb0;p=linux.git

netkit: Reject IFLA_NETKIT_PEER_INFO in netkit_change_link

The IFLA_NETKIT_PEER_INFO attribute can only be used during device
creation, but not via changelink callback. Hence reject it there.

Fixes: 35dfaad7188c ("netkit, bpf: Add bpf programmable net device")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/e86a277a1e8d3b19890312779e42f790b0605ea4.1701115314.git.daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---

diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index 97bd6705c2411..39171380ccf29 100644
--- a/drivers/net/netkit.c
+++ b/drivers/net/netkit.c
@@ -851,6 +851,12 @@ static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
 		return -EACCES;
 	}
 
+	if (data[IFLA_NETKIT_PEER_INFO]) {
+		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO],
+				    "netkit peer info cannot be changed after device creation");
+		return -EINVAL;
+	}
+
 	if (data[IFLA_NETKIT_POLICY]) {
 		attr = data[IFLA_NETKIT_POLICY];
 		policy = nla_get_u32(attr);