bpf: Enable bpf_{g,s}etsockopt in BPF_CGROUP_INET{4,6}_GET{PEER,SOCK}NAME

Those hooks run as BPF_CGROUP_RUN_SA_PROG_LOCK and operate on
a locked socket.

Signed-off-by: Stanislav Fomichev <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

net/core/filter.c

···
 		case BPF_CGROUP_INET6_CONNECT:
 		case BPF_CGROUP_UDP4_SENDMSG:
 		case BPF_CGROUP_UDP6_SENDMSG:
+		case BPF_CGROUP_INET4_GETPEERNAME:
+		case BPF_CGROUP_INET6_GETPEERNAME:
+		case BPF_CGROUP_INET4_GETSOCKNAME:
+		case BPF_CGROUP_INET6_GETSOCKNAME:
 			return &bpf_sock_addr_setsockopt_proto;
 		default:
 			return NULL;
···
 		case BPF_CGROUP_INET6_CONNECT:
 		case BPF_CGROUP_UDP4_SENDMSG:
 		case BPF_CGROUP_UDP6_SENDMSG:
+		case BPF_CGROUP_INET4_GETPEERNAME:
+		case BPF_CGROUP_INET6_GETPEERNAME:
+		case BPF_CGROUP_INET4_GETSOCKNAME:
+		case BPF_CGROUP_INET6_GETSOCKNAME:
 			return &bpf_sock_addr_getsockopt_proto;
 		default:
 			return NULL;

tools/testing/selftests/bpf/progs/connect_force_port4.c

···
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
 
+#include <bpf_sockopt_helpers.h>
+
 char _license[] SEC("license") = "GPL";
 int _version SEC("version") = 1;
 
···
 SEC("cgroup/getsockname4")
 int getsockname4(struct bpf_sock_addr *ctx)
 {
+	if (!get_set_sk_priority(ctx))
+		return 1;
+
 	/* Expose local server as 1.2.3.4:60000 to client. */
 	if (ctx->user_port == bpf_htons(60123)) {
 		ctx->user_ip4 = bpf_htonl(0x01020304);
···
 int getpeername4(struct bpf_sock_addr *ctx)
 {
 	struct svc_addr *orig;
+
+	if (!get_set_sk_priority(ctx))
+		return 1;
 
 	/* Expose service 1.2.3.4:60000 as peer instead of backend. */
 	if (ctx->user_port == bpf_htons(60123)) {

tools/testing/selftests/bpf/progs/connect_force_port6.c

···
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
 
+#include <bpf_sockopt_helpers.h>
+
 char _license[] SEC("license") = "GPL";
 int _version SEC("version") = 1;
 
···
 SEC("cgroup/getsockname6")
 int getsockname6(struct bpf_sock_addr *ctx)
 {
+	if (!get_set_sk_priority(ctx))
+		return 1;
+
 	/* Expose local server as [fc00::1]:60000 to client. */
 	if (ctx->user_port == bpf_htons(60124)) {
 		ctx->user_ip6[0] = bpf_htonl(0xfc000000);
···
 int getpeername6(struct bpf_sock_addr *ctx)
 {
 	struct svc_addr *orig;
+
+	if (!get_set_sk_priority(ctx))
+		return 1;
 
 	/* Expose service [fc00::1]:60000 as peer instead of backend. */
 	if (ctx->user_port == bpf_htons(60124)) {