[net-next] tun: Consistently configure generic netdev params via rtnetlink

Message ID 1539109261-8414-1-git-send-email-serhe.popovych@gmail.com
State Accepted
Delegated to: David Miller
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Series
  • [net-next] tun: Consistently configure generic netdev params via rtnetlink
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Commit Message

Serhey Popovych Oct. 9, 2018, 6:21 p.m.
Configuring generic network device parameters on tun will fail in
presence of IFLA_INFO_KIND attribute in IFLA_LINKINFO nested attribute
since tun_validate() always return failure.

This can be visualized with following ip-link(8) command sequences:

  # ip link set dev tun0 group 100
  # ip link set dev tun0 group 100 type tun
  RTNETLINK answers: Invalid argument

with contrast to dummy and veth drivers:

  # ip link set dev dummy0 group 100
  # ip link set dev dummy0 type dummy

  # ip link set dev veth0 group 100
  # ip link set dev veth0 group 100 type veth

Fix by returning zero in tun_validate() when @data is NULL that is
always in case since rtnl_link_ops->maxtype is zero in tun driver.

Fixes: f019a7a594d9 ("tun: Implement ip link del tunXXX")
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
---
 drivers/net/tun.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

David Miller Oct. 16, 2018, 4:41 a.m. | #1
From: Serhey Popovych <serhe.popovych@gmail.com>
Date: Tue,  9 Oct 2018 21:21:01 +0300

> Configuring generic network device parameters on tun will fail in
> presence of IFLA_INFO_KIND attribute in IFLA_LINKINFO nested attribute
> since tun_validate() always return failure.
> 
> This can be visualized with following ip-link(8) command sequences:
> 
>   # ip link set dev tun0 group 100
>   # ip link set dev tun0 group 100 type tun
>   RTNETLINK answers: Invalid argument
> 
> with contrast to dummy and veth drivers:
> 
>   # ip link set dev dummy0 group 100
>   # ip link set dev dummy0 type dummy
> 
>   # ip link set dev veth0 group 100
>   # ip link set dev veth0 group 100 type veth
> 
> Fix by returning zero in tun_validate() when @data is NULL that is
> always in case since rtnl_link_ops->maxtype is zero in tun driver.
> 
> Fixes: f019a7a594d9 ("tun: Implement ip link del tunXXX")
> Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>

Applied, thank you.

Patch

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index b174342..a3e8a43 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2298,6 +2298,8 @@  static void tun_setup(struct net_device *dev)
 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
 			struct netlink_ext_ack *extack)
 {
+	if (!data)
+		return 0;
 	return -EINVAL;
 }