[PATCH bpf v2] netkit: Reject IFLA_NETKIT_PEER_INFO in netkit_change_link

[PATCH bpf v2] netkit: Reject IFLA_NETKIT_PEER_INFO in netkit_change_link

[Daniel Borkmann]

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>
---
 v1 -> v2:
   - Switch error code from EACCES to EINVAL (Jakub)

 drivers/net/netkit.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index 97bd6705c241..39171380ccf2 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);
-- 
2.21.0

Re: [PATCH bpf v2] netkit: Reject IFLA_NETKIT_PEER_INFO in netkit_change_link

[Jakub Kicinski]

On Mon, 27 Nov 2023 21:05:33 +0100 Daniel Borkmann wrote:
> 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>

Re: [PATCH bpf v2] netkit: Reject IFLA_NETKIT_PEER_INFO in netkit_change_link

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf.git (master)
by Martin KaFai Lau <martin.lau@kernel.org>:

On Mon, 27 Nov 2023 21:05:33 +0100 you wrote:
> 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>
> 
> [...]

Here is the summary with links:
  - [bpf,v2] netkit: Reject IFLA_NETKIT_PEER_INFO in netkit_change_link
    https://git.kernel.org/bpf/bpf/c/0bad281d0ecd

You are awesome, thank you!
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