kernel.git/net/core/rtnetlink.c, branch linux-5.13.y

rtnetlink: Return correct error on changing device netns

2021-09-03T08:22:56Z

[ Upstream commit 96a6b93b69880b2c978e1b2be9cae6970b605008 ] Currently when device is moved between network namespaces using RTM_NEWLINK message type and one of netns attributes (FLA_NET_NS_PID, IFLA_NET_NS_FD, IFLA_TARGET_NETNSID) but w/o specifying IFLA_IFNAME, and target namespace already has device with same name, userspace will get EINVAL what is confusing and makes debugging harder. Fix it so that userspace gets more appropriate EEXIST instead what makes debugging much easier. Before: # ./ifname.sh + ip netns add ns0 + ip netns exec ns0 ip link add l0 type dummy + ip netns exec ns0 ip link show l0 8: l0: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 66:90:b5:d5:78:69 brd ff:ff:ff:ff:ff:ff + ip link add l0 type dummy + ip link show l0 10: l0: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 6e:c6:1f:15:20:8d brd ff:ff:ff:ff:ff:ff + ip link set l0 netns ns0 RTNETLINK answers: Invalid argument After: # ./ifname.sh + ip netns add ns0 + ip netns exec ns0 ip link add l0 type dummy + ip netns exec ns0 ip link show l0 8: l0: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 1e:4a:72:e3:e3:8f brd ff:ff:ff:ff:ff:ff + ip link add l0 type dummy + ip link show l0 10: l0: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether f2:fc:fe:2b:7d:a6 brd ff:ff:ff:ff:ff:ff + ip link set l0 netns ns0 RTNETLINK answers: File exists The problem is that do_setlink() passes its `char *ifname` argument, that it gets from a caller, to __dev_change_net_namespace() as is (as `const char *pat`), but semantics of ifname and pat can be different. For example, __rtnl_newlink() does this: net/core/rtnetlink.c 3270 char ifname[IFNAMSIZ]; ... 3286 if (tb[IFLA_IFNAME]) 3287 nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ); 3288 else 3289 ifname[0] = '\0'; ... 3364 if (dev) { ... 3394 return do_setlink(skb, dev, ifm, extack, tb, ifname, status); 3395 } , i.e. do_setlink() gets ifname pointer that is always valid no matter if user specified IFLA_IFNAME or not and then do_setlink() passes this ifname pointer as is to __dev_change_net_namespace() as pat argument. But the pat (pattern) in __dev_change_net_namespace() is used as: net/core/dev.c 11198 err = -EEXIST; 11199 if (__dev_get_by_name(net, dev->name)) { 11200 /* We get here if we can't use the current device name */ 11201 if (!pat) 11202 goto out; 11203 err = dev_get_valid_name(net, dev, pat); 11204 if (err < 0) 11205 goto out; 11206 } As the result the `goto out` path on line 11202 is neven taken and instead of returning EEXIST defined on line 11198, __dev_change_net_namespace() returns an error from dev_get_valid_name() and this, in turn, will be EINVAL for ifname[0] = '\0' set earlier. Fixes: d8a5ec672768 ("[NET]: netlink support for moving devices between network namespaces.") Signed-off-by: Andrey Ignatov Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

rtnetlink: avoid RCU read lock when holding RTNL

2021-07-14T15:06:56Z

[ Upstream commit a100243d95a60d74ae9bb9df1f5f2192e9aed6a7 ] When we call af_ops->set_link_af() we hold a RCU read lock as we retrieve af_ops from the RCU protected list, but this is unnecessary because we already hold RTNL lock, which is the writer lock for protecting rtnl_af_ops, so it is safer than RCU read lock. Similar for af_ops->validate_link_af(). This was not a problem until we begin to take mutex lock down the path of ->set_link_af() in __ipv6_dev_mc_dec() recently. We can just drop the RCU read lock there and assert RTNL lock. Reported-and-tested-by: syzbot+7d941e89dd48bcf42573@syzkaller.appspotmail.com Fixes: 63ed8de4be81 ("mld: add mc_lock for protecting per-interface mld data") Tested-by: Taehee Yoo Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

rtnetlink: Fix regression in bridge VLAN configuration

2021-06-09T21:58:26Z

Cited commit started returning errors when notification info is not filled by the bridge driver, resulting in the following regression: # ip link add name br1 type bridge vlan_filtering 1 # bridge vlan add dev br1 vid 555 self pvid untagged RTNETLINK answers: Invalid argument As long as the bridge driver does not fill notification info for the bridge device itself, an empty notification should not be considered as an error. This is explained in commit 59ccaaaa49b5 ("bridge: dont send notification when skb->len == 0 in rtnl_bridge_notify"). Fix by removing the error and add a comment to avoid future bugs. Fixes: a8db57c1d285 ("rtnetlink: Fix missing error code in rtnl_bridge_notify()") Signed-off-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Signed-off-by: David S. Miller

rtnetlink: Fix missing error code in rtnl_bridge_notify()

2021-06-03T20:56:27Z

The error code is missing in this code scenario, add the error code '-EINVAL' to the return value 'err'. Eliminate the follow smatch warning: net/core/rtnetlink.c:4834 rtnl_bridge_notify() warn: missing error code 'err'. Reported-by: Abaci Robot Signed-off-by: Jiapeng Chong Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-04-10T03:48:35Z

Conflicts: MAINTAINERS - keep Chandrasekar drivers/net/ethernet/mellanox/mlx5/core/en_main.c - simple fix + trust the code re-added to param.c in -next is fine include/linux/bpf.h - trivial include/linux/ethtool.h - trivial, fix kdoc while at it include/linux/skmsg.h - move to relevant place in tcp.c, comment re-wrapped net/core/skmsg.c - add the sk = sk // sk = NULL around calls net/tipc/crypto.c - trivial Signed-off-by: Jakub Kicinski

ipv6: report errors for iftoken via netlink extack

2021-04-08T20:52:36Z

Setting iftoken can fail for several different reasons but there and there was no report to user as to the cause. Add netlink extended errors to the processing of the request. This requires adding additional argument through rtnl_af_ops set_link_af callback. Reported-by: Hongren Zheng Signed-off-by: Stephen Hemminger Reviewed-by: David Ahern Signed-off-by: David S. Miller

net: remove the new_ifindex argument from dev_change_net_namespace

2021-04-07T21:43:28Z

Here is only one place where we want to specify new_ifindex. In all other cases, callers pass 0 as new_ifindex. It looks reasonable to add a low-level function with new_ifindex and to convert dev_change_net_namespace to a static inline wrapper. Fixes: eeb85a14ee34 ("net: Allow to specify ifindex when device is moved to another namespace") Suggested-by: Jakub Kicinski Signed-off-by: Andrei Vagin Acked-by: Jakub Kicinski Signed-off-by: David S. Miller

net: introduce nla_policy for IFLA_NEW_IFINDEX

2021-04-07T21:42:12Z

In this case, we don't need to check that new_ifindex is positive in validate_linkmsg. Fixes: eeb85a14ee34 ("net: Allow to specify ifindex when device is moved to another namespace") Suggested-by: Jakub Kicinski Signed-off-by: Andrei Vagin Acked-by: Jakub Kicinski Signed-off-by: David S. Miller

net: Allow to specify ifindex when device is moved to another namespace

2021-04-05T21:49:40Z

Currently, we can specify ifindex on link creation. This change allows to specify ifindex when a device is moved to another network namespace. Even now, a device ifindex can be changed if there is another device with the same ifindex in the target namespace. So this change doesn't introduce completely new behavior, it adds more control to the process. CRIU users want to restore containers with pre-created network devices. A user will provide network devices and instructions where they have to be restored, then CRIU will restore network namespaces and move devices into them. The problem is that devices have to be restored with the same indexes that they have before C/R. Cc: Alexander Mikhalitsyn Suggested-by: Christian Brauner Signed-off-by: Andrei Vagin Reviewed-by: Christian Brauner Signed-off-by: David S. Miller

rtnetlink: using dev_base_seq from target net

2021-03-04T00:59:17Z

Signed-off-by: zhang kai Signed-off-by: David S. Miller