Merge branch 'bpf-support-for-sockets'
David Ahern says:
====================
net: Add bpf support for sockets
The recently added VRF support in Linux leverages the bind-to-device
API for programs to specify an L3 domain for a socket. While
SO_BINDTODEVICE has been around for ages, not every ipv4/ipv6 capable
program has support for it. Even for those programs that do support it,
the API requires processes to be started as root (CAP_NET_RAW) which
is not desirable from a general security perspective.
This patch set leverages Daniel Mack's work to attach bpf programs to
a cgroup to provide a capability to set sk_bound_dev_if for all
AF_INET{6} sockets opened by a process in a cgroup when the sockets
are allocated.
For example:
1. configure vrf (e.g., using ifupdown2)
auto eth0
iface eth0 inet dhcp
vrf mgmt
auto mgmt
iface mgmt
vrf-table auto
2. configure cgroup
mount -t cgroup2 none /tmp/cgroupv2
mkdir /tmp/cgroupv2/mgmt
test_cgrp2_sock /tmp/cgroupv2/mgmt 15
3. set shell into cgroup (e.g., can be done at login using pam)
echo $$ >> /tmp/cgroupv2/mgmt/cgroup.procs
At this point all commands run in the shell (e.g, apt) have sockets
automatically bound to the VRF (see output of ss -ap 'dev == <vrf>'),
including processes not running as root.
This capability enables running any program in a VRF context and is key
to deploying Management VRF, a fundamental configuration for networking
gear, with any Linux OS installation.
This patchset also exports the socket family, type and protocol as
read-only allowing bpf filters to deny a process in a cgroup the ability
to open specific types of AF_INET or AF_INET6 sockets.
v7
- comments from Alexei
v6
- add export of socket family, type and protocol
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Showing
samples/bpf/sock_flags_kern.c
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samples/bpf/test_cgrp2_sock.c
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samples/bpf/test_cgrp2_sock.sh
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samples/bpf/test_cgrp2_sock2.c
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samples/bpf/test_cgrp2_sock2.sh
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