bpf,selinux: Allocate bpf_security_struct per BPF token

Utilize newly added bpf_token_create/bpf_token_free LSM hooks to
allocate struct bpf_security_struct for each BPF token object in
SELinux. This just follows similar pattern for BPF prog and map.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-18-andrii@kernel.org

security/selinux/hooks.c

@@ -6965,6 +6965,29 @@ static void selinux_bpf_prog_free(struct bpf_prog *prog)
 	prog->aux->security = NULL;
 	kfree(bpfsec);
 }
+
+static int selinux_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,
+				    struct path *path)
+{
+	struct bpf_security_struct *bpfsec;
+
+	bpfsec = kzalloc(sizeof(*bpfsec), GFP_KERNEL);
+	if (!bpfsec)
+		return -ENOMEM;
+
+	bpfsec->sid = current_sid();
+	token->security = bpfsec;
+
+	return 0;
+}
+
+static void selinux_bpf_token_free(struct bpf_token *token)
+{
+	struct bpf_security_struct *bpfsec = token->security;
+
+	token->security = NULL;
+	kfree(bpfsec);
+}
 #endif
 
 struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = {
@@ -7328,6 +7351,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(bpf_prog, selinux_bpf_prog),
 	LSM_HOOK_INIT(bpf_map_free, selinux_bpf_map_free),
 	LSM_HOOK_INIT(bpf_prog_free, selinux_bpf_prog_free),
+	LSM_HOOK_INIT(bpf_token_free, selinux_bpf_token_free),
 #endif
 
 #ifdef CONFIG_PERF_EVENTS
@@ -7386,6 +7410,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
 #ifdef CONFIG_BPF_SYSCALL
 	LSM_HOOK_INIT(bpf_map_create, selinux_bpf_map_create),
 	LSM_HOOK_INIT(bpf_prog_load, selinux_bpf_prog_load),
+	LSM_HOOK_INIT(bpf_token_create, selinux_bpf_token_create),
 #endif
 #ifdef CONFIG_PERF_EVENTS
 	LSM_HOOK_INIT(perf_event_alloc, selinux_perf_event_alloc),