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// SPDX-License-Identifier: GPL-2.0
#include "vmlinux.h"
#include "bpf_tracing_net.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
char _license[] SEC("license") = "GPL";
#ifndef AF_PACKET
#define AF_PACKET 17
#endif
#ifndef AF_UNIX
#define AF_UNIX 1
#endif
#ifndef EPERM
#define EPERM 1
#endif
struct {
__uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
__type(key, __u64);
__type(value, __u64);
} cgroup_storage SEC(".maps");
int called_socket_post_create;
int called_socket_post_create2;
int called_socket_bind;
int called_socket_bind2;
int called_socket_alloc;
int called_socket_clone;
static __always_inline int test_local_storage(void)
{
__u64 *val;
val = bpf_get_local_storage(&cgroup_storage, 0);
if (!val)
return 0;
*val += 1;
return 1;
}
static __always_inline int real_create(struct socket *sock, int family,
int protocol)
{
struct sock *sk;
int prio = 123;
/* Reject non-tx-only AF_PACKET. */
if (family == AF_PACKET && protocol != 0)
return 0; /* EPERM */
sk = sock->sk;
if (!sk)
return 1;
/* The rest of the sockets get default policy. */
if (bpf_setsockopt(sk, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio)))
return 0; /* EPERM */
/* Make sure bpf_getsockopt is allowed and works. */
prio = 0;
if (bpf_getsockopt(sk, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio)))
return 0; /* EPERM */
if (prio != 123)
return 0; /* EPERM */
/* Can access cgroup local storage. */
if (!test_local_storage())
return 0; /* EPERM */
return 1;
}
/* __cgroup_bpf_run_lsm_socket */
SEC("lsm_cgroup/socket_post_create")
int BPF_PROG(socket_post_create, struct socket *sock, int family,
int type, int protocol, int kern)
{
called_socket_post_create++;
return real_create(sock, family, protocol);
}
/* __cgroup_bpf_run_lsm_socket */
SEC("lsm_cgroup/socket_post_create")
int BPF_PROG(socket_post_create2, struct socket *sock, int family,
int type, int protocol, int kern)
{
called_socket_post_create2++;
return real_create(sock, family, protocol);
}
static __always_inline int real_bind(struct socket *sock,
struct sockaddr *address,
int addrlen)
{
struct sockaddr_ll sa = {};
if (sock->sk->__sk_common.skc_family != AF_PACKET)
return 1;
if (sock->sk->sk_kern_sock)
return 1;
bpf_probe_read_kernel(&sa, sizeof(sa), address);
if (sa.sll_protocol)
return 0; /* EPERM */
/* Can access cgroup local storage. */
if (!test_local_storage())
return 0; /* EPERM */
return 1;
}
/* __cgroup_bpf_run_lsm_socket */
SEC("lsm_cgroup/socket_bind")
int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address,
int addrlen)
{
called_socket_bind++;
return real_bind(sock, address, addrlen);
}
/* __cgroup_bpf_run_lsm_socket */
SEC("lsm_cgroup/socket_bind")
int BPF_PROG(socket_bind2, struct socket *sock, struct sockaddr *address,
int addrlen)
{
called_socket_bind2++;
return real_bind(sock, address, addrlen);
}
/* __cgroup_bpf_run_lsm_current (via bpf_lsm_current_hooks) */
SEC("lsm_cgroup/sk_alloc_security")
int BPF_PROG(socket_alloc, struct sock *sk, int family, gfp_t priority)
{
called_socket_alloc++;
if (family == AF_UNIX)
return 0; /* EPERM */
/* Can access cgroup local storage. */
if (!test_local_storage())
return 0; /* EPERM */
return 1;
}
/* __cgroup_bpf_run_lsm_sock */
SEC("lsm_cgroup/inet_csk_clone")
int BPF_PROG(socket_clone, struct sock *newsk, const struct request_sock *req)
{
int prio = 234;
if (!newsk)
return 1;
/* Accepted request sockets get a different priority. */
if (bpf_setsockopt(newsk, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio)))
return 1;
/* Make sure bpf_getsockopt is allowed and works. */
prio = 0;
if (bpf_getsockopt(newsk, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio)))
return 1;
if (prio != 234)
return 1;
/* Can access cgroup local storage. */
if (!test_local_storage())
return 1;
called_socket_clone++;
return 1;
}
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