Users have reported a regression due to ip now dropping capabilities
unconditionally.
zerotier-one VPN and VirtualBox use ambient capabilities in their
binary and then fork out to ip to set routes and links, and this
does not work anymore.
As a workaround, do not drop caps if CAP_NET_ADMIN (the most common
capability used by ip) is set with the INHERITABLE flag.
Users that want ip vrf exec to work do not need to set INHERITABLE,
which will then only set when the calling program had privileges to
give itself the ambient capability.
Fixes: ba2fc55b99 ("Drop capabilities if not running ip exec vrf with libcap")
Signed-off-by: Luca Boccassi <bluca@debian.org>
ip vrf exec requires root or CAP_NET_ADMIN, CAP_SYS_ADMIN and
CAP_DAC_OVERRIDE. It is not possible to run unprivileged commands like
ping as non-root or non-cap-enabled due to this requirement.
To allow users and administrators to safely add the required
capabilities to the binary, drop all capabilities on start if not
invoked with "vrf exec".
Update the manpage with the requirements.
Signed-off-by: Luca Boccassi <bluca@debian.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
'ip vrf' follows the user semnatics established by 'ip netns'.
The 'ip vrf' subcommand supports 3 usages:
1. Run a command against a given vrf:
ip vrf exec NAME CMD
Uses the recently committed cgroup/sock BPF option. vrf directory
is added to cgroup2 mount. Individual vrfs are created under it. BPF
filter attached to vrf/NAME cgroup2 to set sk_bound_dev_if to the VRF
device index. From there the current process (ip's pid) is addded to
the cgroups.proc file and the given command is exected. In doing so
all AF_INET/AF_INET6 (ipv4/ipv6) sockets are automatically bound to
the VRF domain.
The association is inherited parent to child allowing the command to
be a shell from which other commands are run relative to the VRF.
2. Show the VRF a process is bound to:
ip vrf id
This command essentially looks at /proc/pid/cgroup for a "::/vrf/"
entry with the VRF name following.
3. Show process ids bound to a VRF
ip vrf pids NAME
This command dumps the file MNT/vrf/NAME/cgroup.procs since that file
shows the process ids in the particular vrf cgroup.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
