bpf: Make sure all tail call callers use cgroup storage if the owner does

kernel/bpf/core.c

@@ -2419,8 +2419,7 @@ static bool __bpf_prog_map_compatible(struct bpf_map *map,
 				break;
 			cookie = aux->cgroup_storage[i] ?
 				 aux->cgroup_storage[i]->cookie : 0;
-			ret = map->owner->storage_cookie[i] == cookie ||
-			      !cookie;
+			ret = map->owner->storage_cookie[i] == cookie;
 		}
 		if (ret &&
 		    map->owner->attach_func_proto != aux->attach_func_proto) {

tools/testing/selftests/bpf/prog_tests/tailcalls.c

@@ -8,6 +8,9 @@
 #include "tailcall_freplace.skel.h"
 #include "tc_bpf2bpf.skel.h"
 #include "tailcall_fail.skel.h"
+#include "tailcall_cgrp_storage_owner.skel.h"
+#include "tailcall_cgrp_storage_no_storage.skel.h"
+#include "tailcall_cgrp_storage.skel.h"
 
 /* test_tailcall_1 checks basic functionality by patching multiple locations
  * in a single program for a single tail call slot with nop->jmp, jmp->nop
@@ -1648,6 +1651,116 @@ static void test_tailcall_bpf2bpf_freplace(void)
 	tc_bpf2bpf__destroy(tc_skel);
 }
 
+/*
+ * test_tail_call_cgrp_storage checks that if the owner program of a program
+ * array uses cgroup storage, other callers and callees must also use the
+ * exact same cgroup storage.
+ */
+static void test_tailcall_cgrp_storage(void)
+{
+	int err, prog_fd, prog_array_fd, storage_map_fd, key = 0;
+	struct tailcall_cgrp_storage_owner *owner_skel;
+	struct tailcall_cgrp_storage *skel;
+
+	/* Load owner_skel first to make sure it becomes the owner of prog_array */
+	owner_skel = tailcall_cgrp_storage_owner__open_and_load();
+	if (!ASSERT_OK_PTR(owner_skel, "tailcall_cgrp_storage_owner__open_and_load"))
+		return;
+
+	prog_array_fd = bpf_map__fd(owner_skel->maps.prog_array);
+	storage_map_fd = bpf_map__fd(owner_skel->maps.storage_map);
+
+	skel = tailcall_cgrp_storage__open();
+	if (!ASSERT_OK_PTR(skel, "tailcall_cgrp_storage__open")) {
+		tailcall_cgrp_storage_owner__destroy(owner_skel);
+		return;
+	}
+
+	err = bpf_map__reuse_fd(skel->maps.prog_array, prog_array_fd);
+	ASSERT_OK(err, "bpf_map__reuse_fd(prog_array)");
+
+	err = bpf_map__reuse_fd(skel->maps.storage_map, storage_map_fd);
+	ASSERT_OK(err, "bpf_map__reuse_fd(storage_map)");
+
+	err = bpf_object__load(skel->obj);
+	ASSERT_OK(err, "bpf_object__load");
+
+	prog_fd = bpf_program__fd(skel->progs.callee_prog);
+
+	err = bpf_map_update_elem(prog_array_fd, &key, &prog_fd, BPF_ANY);
+	ASSERT_OK(err, "bpf_map_update_elem(prog_array)");
+
+	tailcall_cgrp_storage__destroy(skel);
+	tailcall_cgrp_storage_owner__destroy(owner_skel);
+}
+
+/*
+ * test_tail_call_cgrp_storage_diff_storage checks that a program using tail call
+ * is rejected if it uses a cgroup storage different from the owner's.
+ */
+static void test_tailcall_cgrp_storage_diff_storage(void)
+{
+	struct tailcall_cgrp_storage_owner *owner_skel;
+	struct tailcall_cgrp_storage *skel;
+	int err, prog_array_fd;
+
+	/* Load owner_skel first to make sure it becomes the owner of prog_array */
+	owner_skel = tailcall_cgrp_storage_owner__open_and_load();
+	if (!ASSERT_OK_PTR(owner_skel, "tailcall_cgrp_storage_owner__open_and_load"))
+		return;
+
+	prog_array_fd = bpf_map__fd(owner_skel->maps.prog_array);
+
+	skel = tailcall_cgrp_storage__open();
+	if (!ASSERT_OK_PTR(skel, "tailcall_cgrp_storage__open")) {
+		tailcall_cgrp_storage_owner__destroy(owner_skel);
+		return;
+	}
+
+	err = bpf_map__reuse_fd(skel->maps.prog_array, prog_array_fd);
+	ASSERT_OK(err, "bpf_map__reuse_fd(prog_array)");
+
+	err = bpf_object__load(skel->obj);
+	ASSERT_ERR(err, "bpf_object__load");
+
+	tailcall_cgrp_storage__destroy(skel);
+	tailcall_cgrp_storage_owner__destroy(owner_skel);
+}
+
+/*
+ * test_tail_call_cgrp_storage_no_storage checks that a program using tail call
+ * is rejected if it does not use cgroup storage while the owner does.
+ */
+static void test_tailcall_cgrp_storage_no_storage(void)
+{
+	struct tailcall_cgrp_storage_owner *owner_skel;
+	struct tailcall_cgrp_storage_no_storage *skel;
+	int err, prog_array_fd, storage_map_fd;
+
+	/* Load owner_skel first to make sure it becomes the owner of prog_array */
+	owner_skel = tailcall_cgrp_storage_owner__open_and_load();
+	if (!ASSERT_OK_PTR(owner_skel, "tailcall_cgrp_storage_owner__open_and_load"))
+		return;
+
+	prog_array_fd = bpf_map__fd(owner_skel->maps.prog_array);
+	storage_map_fd = bpf_map__fd(owner_skel->maps.storage_map);
+
+	skel = tailcall_cgrp_storage_no_storage__open();
+	if (!ASSERT_OK_PTR(skel, "tailcall_cgrp_storage_no_storage__open")) {
+		tailcall_cgrp_storage_owner__destroy(owner_skel);
+		return;
+	}
+
+	err = bpf_map__reuse_fd(skel->maps.prog_array, prog_array_fd);
+	ASSERT_OK(err, "bpf_map__reuse_fd(prog_array)");
+
+	err = bpf_object__load(skel->obj);
+	ASSERT_ERR(err, "bpf_object__load");
+
+	tailcall_cgrp_storage_no_storage__destroy(skel);
+	tailcall_cgrp_storage_owner__destroy(owner_skel);
+}
+
 static void test_tailcall_failure()
 {
 	RUN_TESTS(tailcall_fail);
@@ -1705,6 +1818,12 @@ void test_tailcalls(void)
 		test_tailcall_freplace();
 	if (test__start_subtest("tailcall_bpf2bpf_freplace"))
 		test_tailcall_bpf2bpf_freplace();
+	if (test__start_subtest("tailcall_cgrp_storage"))
+		test_tailcall_cgrp_storage();
+	if (test__start_subtest("tailcall_cgrp_storage_diff_storage"))
+		test_tailcall_cgrp_storage_diff_storage();
+	if (test__start_subtest("tailcall_cgrp_storage_no_storage"))
+		test_tailcall_cgrp_storage_no_storage();
 	if (test__start_subtest("tailcall_failure"))
 		test_tailcall_failure();
 }

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

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
+	__type(key, struct bpf_cgroup_storage_key);
+	__type(value, __u64);
+} storage_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(max_entries, 1);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u32));
+} prog_array SEC(".maps");
+
+SEC("cgroup_skb/egress")
+int caller_prog(struct __sk_buff *skb)
+{
+	__u64 *storage;
+
+	storage = bpf_get_local_storage(&storage_map, 0);
+	if (storage)
+		*storage = 1;
+
+	bpf_tail_call(skb, &prog_array, 0);
+
+	return 1;
+}
+
+SEC("cgroup_skb/egress")
+int callee_prog(struct __sk_buff *skb)
+{
+	__u64 *storage;
+
+	storage = bpf_get_local_storage(&storage_map, 0);
+	if (storage)
+		*storage = 1;
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";

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

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(max_entries, 1);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u32));
+} prog_array SEC(".maps");
+
+SEC("cgroup_skb/egress")
+int caller_prog(struct __sk_buff *skb)
+{
+	bpf_tail_call(skb, &prog_array, 0);
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";

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

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
+	__type(key, struct bpf_cgroup_storage_key);
+	__type(value, __u64);
+} storage_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(max_entries, 1);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u32));
+} prog_array SEC(".maps");
+
+SEC("cgroup_skb/egress")
+int prog_array_owner(struct __sk_buff *skb)
+{
+	__u64 *storage;
+
+	storage = bpf_get_local_storage(&storage_map, 0);
+	if (storage)
+		*storage = 1;
+
+	bpf_tail_call(skb, &prog_array, 0);
+
+	return 1;
+}
+
+char _license[] SEC("license") = "GPL";