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@cumulusnetworks.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/samples/bpf/sock_flags_kern.c b/samples/bpf/sock_flags_kern.c
new file mode 100644
index 0000000..533dd11a6
--- /dev/null
+++ b/samples/bpf/sock_flags_kern.c
@@ -0,0 +1,44 @@
+#include <uapi/linux/bpf.h>
+#include <linux/socket.h>
+#include <linux/net.h>
+#include <uapi/linux/in.h>
+#include <uapi/linux/in6.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 == SOCK_RAW &&
+ sk->protocol == IPPROTO_ICMPV6)
+ 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 == SOCK_RAW &&
+ sk->protocol == IPPROTO_ICMP)
+ return 0;
+
+ return 1;
+}
+
+char _license[] SEC("license") = "GPL";