Marcel reported to see the following message when autoloading
is being triggered when adding nlmon device:
Loading kernel module for a network device with
CAP_SYS_MODULE (deprecated). Use CAP_NET_ADMIN and alias
netdev-nlmon instead.
This false-positive happens despite with having correct
capabilities set, e.g. through issuing `ip link del dev nlmon`
more than once on a valid device with name nlmon, but Marcel
has also seen it on creation time when no nlmon module is
previously compiled-in or loaded as module and the device
name equals a link type name (e.g. nlmon, vxlan, team).
Stephen says:
The netdev module alias is a hold over from the past. For
normal devices, people used to create a alias eth0 to and
point it to the type of network device used, that was back
in the bad old ISA days before real discovery.
Also, the tunnels create module alias for the control device
and ip used to use this to autoload the tunnel device.
The message is bogus and should just be removed, I also see
it in a couple of other cases where tap devices are renamed
for other usese.
As mentioned in 8909c9ad8f ("net: don't allow CAP_NET_ADMIN
to load non-netdev kernel modules"), we nevertheless still
might want to leave the old autoloading behaviour in place
as it could break old scripts, so for now, lets just remove
the log message as Stephen suggests.
Reference: http://thread.gmane.org/gmane.linux.kernel/1105168
Reported-by: Marcel Holtmann <marcel@holtmann.org>
Suggested-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
SIOCSHWTSTAMP returns the real configuration to the application
using it, but there is currently no way for any other
application to find out the configuration non-destructively.
Add a new ioctl for this, making it unprivileged.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
When the kernel (compiled with CONFIG_PREEMPT=n) is performing the
rename of a network interface, it can end up waiting for a workqueue
to complete. If userland is able to invoke a SIOCGIFNAME ioctl or a
SO_BINDTODEVICE getsockopt in between, the kernel will deadlock due to
the fact that read_secklock_begin() will spin forever waiting for the
writer process (the one doing the interface rename) to update the
devnet_rename_seq sequence.
This patch fixes the problem by adding a helper (netdev_get_name())
and using it in the code handling the SIOCGIFNAME ioctl and
SO_BINDTODEVICE setsockopt.
The netdev_get_name() helper uses raw_seqcount_begin() to avoid
spinning forever, waiting for devnet_rename_seq->sequence to become
even. cond_resched() is used in the contended case, before retrying
the access to give the writer process a chance to finish.
The use of raw_seqcount_begin() will incur some unneeded work in the
reader process in the contended case, but this is better than
deadlocking the system.
Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
They well deserve a separated unit.
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
