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:
https://www.mail-archive.com/netdev@vger.kernel.org/msg134028.html
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.
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.
v2
- addressed Daniel's comments: dropped the bpf_sock_store_u32 helper
and used bpf_prog_run_save_cb on the code move
- picked up Mickaël Salaün's subtype patch with a few small tweaks
- removed new prog type in favor of a subtype on the BPF_PROG_TYPE_CGROUP
from Daniel Mack's patch set
- moved the filter hook from sk_alloc to inet{6}_create
David Ahern (5):
bpf: Refactor cgroups code in prep for new type
bpf: Add eBPF program subtype and is_valid_subtype() verifier
bpf: Add new cgroup attach type to enable sock modifications
samples: bpf: Add prog_subtype to bpf_prog_load
samples: bpf: add userspace example for modifying sk_bound_dev_if
include/linux/bpf.h | 7 ++-
include/linux/filter.h | 3 +-
include/uapi/linux/bpf.h | 15 +++++-
kernel/bpf/cgroup.c | 36 +++++++++++--
kernel/bpf/syscall.c | 11 ++--
kernel/bpf/verifier.c | 10 +++-
kernel/trace/bpf_trace.c | 16 ++++--
net/core/filter.c | 115 +++++++++++++++++++++++++++++++++-------
net/ipv4/af_inet.c | 4 ++
net/ipv6/af_inet6.c | 3 ++
samples/bpf/Makefile | 2 +
samples/bpf/bpf_load.c | 2 +-
samples/bpf/fds_example.c | 2 +-
samples/bpf/libbpf.c | 5 +-
samples/bpf/libbpf.h | 3 +-
samples/bpf/sock_example.c | 2 +-
samples/bpf/test_cgrp2_attach.c | 4 +-
samples/bpf/test_cgrp2_sock.c | 84 +++++++++++++++++++++++++++++
18 files changed, 280 insertions(+), 44 deletions(-)
create mode 100644 samples/bpf/test_cgrp2_sock.c
--
2.1.4
