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Date: Wed, 30 Nov 2016 10:16:50 -0800
From: David Ahern <dsa@...ulusnetworks.com>
To: netdev@...r.kernel.org
Cc: daniel@...que.org, ast@...com, daniel@...earbox.net,
maheshb@...gle.com, tgraf@...g.ch,
David Ahern <dsa@...ulusnetworks.com>
Subject: [PATCH net-next v6 6/6] samples/bpf: add userspace example for prohibiting sockets
Add examples preventing a process in a cgroup from opening a socket
based family, protocol and type.
Signed-off-by: David Ahern <dsa@...ulusnetworks.com>
---
v6
- new patch for version 6
samples/bpf/Makefile | 4 ++
samples/bpf/sock_flags_kern.c | 37 +++++++++++++++++++
samples/bpf/test_cgrp2_sock2.c | 66 +++++++++++++++++++++++++++++++++
samples/bpf/test_cgrp2_sock2.sh | 81 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 188 insertions(+)
create mode 100644 samples/bpf/sock_flags_kern.c
create mode 100644 samples/bpf/test_cgrp2_sock2.c
create mode 100755 samples/bpf/test_cgrp2_sock2.sh
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index a335b218198e..8df12f9429dc 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -24,6 +24,7 @@ hostprogs-y += test_overhead
hostprogs-y += test_cgrp2_array_pin
hostprogs-y += test_cgrp2_attach
hostprogs-y += test_cgrp2_sock
+hostprogs-y += test_cgrp2_sock2
hostprogs-y += xdp1
hostprogs-y += xdp2
hostprogs-y += test_current_task_under_cgroup
@@ -53,6 +54,7 @@ test_overhead-objs := bpf_load.o libbpf.o test_overhead_user.o
test_cgrp2_array_pin-objs := libbpf.o test_cgrp2_array_pin.o
test_cgrp2_attach-objs := libbpf.o test_cgrp2_attach.o
test_cgrp2_sock-objs := libbpf.o test_cgrp2_sock.o
+test_cgrp2_sock2-objs := bpf_load.o libbpf.o test_cgrp2_sock2.o
xdp1-objs := bpf_load.o libbpf.o xdp1_user.o
# reuse xdp1 source intentionally
xdp2-objs := bpf_load.o libbpf.o xdp1_user.o
@@ -73,6 +75,7 @@ always += tracex3_kern.o
always += tracex4_kern.o
always += tracex5_kern.o
always += tracex6_kern.o
+always += sock_flags_kern.o
always += test_probe_write_user_kern.o
always += trace_output_kern.o
always += tcbpf1_kern.o
@@ -106,6 +109,7 @@ HOSTLOADLIBES_tracex3 += -lelf
HOSTLOADLIBES_tracex4 += -lelf -lrt
HOSTLOADLIBES_tracex5 += -lelf
HOSTLOADLIBES_tracex6 += -lelf
+HOSTLOADLIBES_test_cgrp2_sock2 += -lelf
HOSTLOADLIBES_test_probe_write_user += -lelf
HOSTLOADLIBES_trace_output += -lelf -lrt
HOSTLOADLIBES_lathist += -lelf
diff --git a/samples/bpf/sock_flags_kern.c b/samples/bpf/sock_flags_kern.c
new file mode 100644
index 000000000000..d6a7f0013a5d
--- /dev/null
+++ b/samples/bpf/sock_flags_kern.c
@@ -0,0 +1,37 @@
+#include <uapi/linux/bpf.h>
+#include <linux/socket.h>
+#include "bpf_helpers.h"
+
+SEC("cgroup/sock1")
+int bpf_prog1(struct bpf_sock *sk)
+{
+ char fmt[] = "socket: family %d type %d protocol %d\n";
+
+ bpf_trace_printk(fmt, sizeof(fmt), sk->family, sk->type, sk->protocol);
+
+ /* block PF_INET6, SOCK_RAW, IPPROTO_ICMPV6 sockets
+ * ie., make ping6 fail
+ */
+ if (sk->family == PF_INET6 && sk->type == 3 && sk->protocol == 58)
+ return 0;
+
+ return 1;
+}
+
+SEC("cgroup/sock2")
+int bpf_prog2(struct bpf_sock *sk)
+{
+ char fmt[] = "socket: family %d type %d protocol %d\n";
+
+ bpf_trace_printk(fmt, sizeof(fmt), sk->family, sk->type, sk->protocol);
+
+ /* block PF_INET, SOCK_RAW, IPPROTO_ICMP sockets
+ * ie., make ping fail
+ */
+ if (sk->family == PF_INET && sk->type == 3 && sk->protocol == 1)
+ return 0;
+
+ return 1;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/samples/bpf/test_cgrp2_sock2.c b/samples/bpf/test_cgrp2_sock2.c
new file mode 100644
index 000000000000..455ef0d06e93
--- /dev/null
+++ b/samples/bpf/test_cgrp2_sock2.c
@@ -0,0 +1,66 @@
+/* eBPF example program:
+ *
+ * - Loads eBPF program
+ *
+ * The eBPF program loads a filter from file and attaches the
+ * program to a cgroup using BPF_PROG_ATTACH
+ */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <net/if.h>
+#include <linux/bpf.h>
+
+#include "libbpf.h"
+#include "bpf_load.h"
+
+static int usage(const char *argv0)
+{
+ printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
+ return EXIT_FAILURE;
+}
+
+int main(int argc, char **argv)
+{
+ int cg_fd, ret, filter_id = 0;
+
+ if (argc < 3)
+ return usage(argv[0]);
+
+ cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
+ if (cg_fd < 0) {
+ printf("Failed to open cgroup path: '%s'\n", strerror(errno));
+ return EXIT_FAILURE;
+ }
+
+ if (load_bpf_file(argv[2]))
+ return EXIT_FAILURE;
+
+ printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);
+
+ if (argc > 3)
+ filter_id = atoi(argv[3]);
+
+ if (filter_id > prog_cnt) {
+ printf("Invalid program id; program not found in file\n");
+ return EXIT_FAILURE;
+ }
+
+ ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
+ BPF_CGROUP_INET_SOCK_CREATE);
+ if (ret < 0) {
+ printf("Failed to attach prog to cgroup: '%s'\n",
+ strerror(errno));
+ return EXIT_FAILURE;
+ }
+
+ return EXIT_SUCCESS;
+}
diff --git a/samples/bpf/test_cgrp2_sock2.sh b/samples/bpf/test_cgrp2_sock2.sh
new file mode 100755
index 000000000000..891f12a0e26f
--- /dev/null
+++ b/samples/bpf/test_cgrp2_sock2.sh
@@ -0,0 +1,81 @@
+#!/bin/bash
+
+function config_device {
+ ip netns add at_ns0
+ ip link add veth0 type veth peer name veth0b
+ ip link set veth0b up
+ ip link set veth0 netns at_ns0
+ ip netns exec at_ns0 ip addr add 172.16.1.100/24 dev veth0
+ ip netns exec at_ns0 ip addr add 2401:db00::1/64 dev veth0 nodad
+ ip netns exec at_ns0 ip link set dev veth0 up
+ ip addr add 172.16.1.101/24 dev veth0b
+ ip addr add 2401:db00::2/64 dev veth0b nodad
+}
+
+function config_cgroup {
+ rm -rf /tmp/cgroupv2
+ mkdir -p /tmp/cgroupv2
+ mount -t cgroup2 none /tmp/cgroupv2
+ mkdir -p /tmp/cgroupv2/foo
+ echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
+}
+
+
+function attach_bpf {
+ test_cgrp2_sock2 /tmp/cgroupv2/foo sock_flags_kern.o $1
+ [ $? -ne 0 ] && exit 1
+}
+
+function cleanup {
+ ip link del veth0b
+ ip netns delete at_ns0
+ umount /tmp/cgroupv2
+ rm -rf /tmp/cgroupv2
+}
+
+cleanup 2>/dev/null
+
+set -e
+config_device
+config_cgroup
+set +e
+
+#
+# Test 1 - fail ping6
+#
+attach_bpf 0
+ping -c1 -w1 172.16.1.100
+if [ $? -ne 0 ]; then
+ echo "ping failed when it should succeed"
+ cleanup
+ exit 1
+fi
+
+ping6 -c1 -w1 2401:db00::1
+if [ $? -eq 0 ]; then
+ echo "ping6 succeeded when it should not"
+ cleanup
+ exit 1
+fi
+
+#
+# Test 2 - fail ping
+#
+attach_bpf 1
+ping6 -c1 -w1 2401:db00::1
+if [ $? -ne 0 ]; then
+ echo "ping6 failed when it should succeed"
+ cleanup
+ exit 1
+fi
+
+ping -c1 -w1 172.16.1.100
+if [ $? -eq 0 ]; then
+ echo "ping succeeded when it should not"
+ cleanup
+ exit 1
+fi
+
+cleanup
+echo
+echo "*** PASS ***"
--
2.1.4
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