selftests/bpf: Ensure cgroup/connect{4,6} programs can bind unpriv ICMP ping

This tests that when an unprivileged ICMP ping socket connects,
the hooks are actually invoked. We also ensure that if the hook does
not call bpf_bind(), the bound address is unmodified, and if the
hook calls bpf_bind(), the bound address is exactly what we provided
to the helper.

A new netns is used to enable ping_group_range in the test without
affecting ouside of the test, because by default, not even root is
permitted to use unprivileged ICMP ping...

Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Link: https://lore.kernel.org/r/086b227c1b97f4e94193e58aae7576d0261b68a4.1662682323.git.zhuyifei@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/connect_ping.c b/tools/testing/selftests/bpf/progs/connect_ping.c
new file mode 100644
index 000000000000..60178192b672
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/connect_ping.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright 2022 Google LLC.
+ */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+
+/* 2001:db8::1 */
+#define BINDADDR_V6 { { { 0x20,0x01,0x0d,0xb8,0,0,0,0,0,0,0,0,0,0,0,1 } } }
+
+__u32 do_bind = 0;
+__u32 has_error = 0;
+__u32 invocations_v4 = 0;
+__u32 invocations_v6 = 0;
+
+SEC("cgroup/connect4")
+int connect_v4_prog(struct bpf_sock_addr *ctx)
+{
+	struct sockaddr_in sa = {
+		.sin_family = AF_INET,
+		.sin_addr.s_addr = bpf_htonl(0x01010101),
+	};
+
+	__sync_fetch_and_add(&invocations_v4, 1);
+
+	if (do_bind && bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)))
+		has_error = 1;
+
+	return 1;
+}
+
+SEC("cgroup/connect6")
+int connect_v6_prog(struct bpf_sock_addr *ctx)
+{
+	struct sockaddr_in6 sa = {
+		.sin6_family = AF_INET6,
+		.sin6_addr = BINDADDR_V6,
+	};
+
+	__sync_fetch_and_add(&invocations_v6, 1);
+
+	if (do_bind && bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)))
+		has_error = 1;
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";