From: YiFei Zhu <zhuyifei@google.com>
Date: Thu, 16 Dec 2021 02:04:28 +0000
Subject: selftests/bpf: Test bpf_{get,set}_retval behavior with cgroup/sockopt
Patch-mainline: v5.18-rc1
Git-commit: b8bff6f890513e0ae0f711e481b368c1d133c558
References: jsc#PED-1377
The tests checks how different ways of interacting with the helpers
(getting retval, setting EUNATCH, EISCONN, and legacy reject
returning 0 without setting retval), produce different results in
both the setsockopt syscall and the retval returned by the helper.
A few more tests verify the interaction between the retval of the
helper and the retval in getsockopt context.
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/43ec60d679ae3f4f6fd2460559c28b63cb93cd12.1639619851.git.zhuyifei@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/testing/selftests/bpf/prog_tests/cgroup_getset_retval.c | 481 ++++++++++
tools/testing/selftests/bpf/progs/cgroup_getset_retval_getsockopt.c | 45
tools/testing/selftests/bpf/progs/cgroup_getset_retval_setsockopt.c | 52 +
3 files changed, 578 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_getset_retval.c
create mode 100644 tools/testing/selftests/bpf/progs/cgroup_getset_retval_getsockopt.c
create mode 100644 tools/testing/selftests/bpf/progs/cgroup_getset_retval_setsockopt.c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_getset_retval.c
@@ -0,0 +1,481 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright 2021 Google LLC.
+ */
+
+#include <test_progs.h>
+#include <cgroup_helpers.h>
+#include <network_helpers.h>
+
+#include "cgroup_getset_retval_setsockopt.skel.h"
+#include "cgroup_getset_retval_getsockopt.skel.h"
+
+#define SOL_CUSTOM 0xdeadbeef
+
+static int zero;
+
+static void test_setsockopt_set(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_setsockopt *obj;
+ struct bpf_link *link_set_eunatch = NULL;
+
+ obj = cgroup_getset_retval_setsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach setsockopt that sets EUNATCH, assert that
+ * we actually get that error when we run setsockopt()
+ */
+ link_set_eunatch = bpf_program__attach_cgroup(obj->progs.set_eunatch,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eunatch, "cg-attach-set_eunatch"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
+ &zero, sizeof(int)), "setsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EUNATCH, "setsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 1, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_set_eunatch);
+
+ cgroup_getset_retval_setsockopt__destroy(obj);
+}
+
+static void test_setsockopt_set_and_get(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_setsockopt *obj;
+ struct bpf_link *link_set_eunatch = NULL, *link_get_retval = NULL;
+
+ obj = cgroup_getset_retval_setsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach setsockopt that sets EUNATCH, and one that gets the
+ * previously set errno. Assert that we get the same errno back.
+ */
+ link_set_eunatch = bpf_program__attach_cgroup(obj->progs.set_eunatch,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eunatch, "cg-attach-set_eunatch"))
+ goto close_bpf_object;
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
+ &zero, sizeof(int)), "setsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EUNATCH, "setsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 2, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, -EUNATCH, "retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_set_eunatch);
+ bpf_link__destroy(link_get_retval);
+
+ cgroup_getset_retval_setsockopt__destroy(obj);
+}
+
+static void test_setsockopt_default_zero(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_setsockopt *obj;
+ struct bpf_link *link_get_retval = NULL;
+
+ obj = cgroup_getset_retval_setsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach setsockopt that gets the previously set errno.
+ * Assert that, without anything setting one, we get 0.
+ */
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+
+ if (!ASSERT_OK(setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
+ &zero, sizeof(int)), "setsockopt"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 1, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, 0, "retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_get_retval);
+
+ cgroup_getset_retval_setsockopt__destroy(obj);
+}
+
+static void test_setsockopt_default_zero_and_set(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_setsockopt *obj;
+ struct bpf_link *link_get_retval = NULL, *link_set_eunatch = NULL;
+
+ obj = cgroup_getset_retval_setsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach setsockopt that gets the previously set errno, and then
+ * one that sets the errno to EUNATCH. Assert that the get does not
+ * see EUNATCH set later, and does not prevent EUNATCH from being set.
+ */
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+ link_set_eunatch = bpf_program__attach_cgroup(obj->progs.set_eunatch,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eunatch, "cg-attach-set_eunatch"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
+ &zero, sizeof(int)), "setsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EUNATCH, "setsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 2, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, 0, "retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_get_retval);
+ bpf_link__destroy(link_set_eunatch);
+
+ cgroup_getset_retval_setsockopt__destroy(obj);
+}
+
+static void test_setsockopt_override(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_setsockopt *obj;
+ struct bpf_link *link_set_eunatch = NULL, *link_set_eisconn = NULL;
+ struct bpf_link *link_get_retval = NULL;
+
+ obj = cgroup_getset_retval_setsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach setsockopt that sets EUNATCH, then one that sets EISCONN,
+ * and then one that gets the exported errno. Assert both the syscall
+ * and the helper sees the last set errno.
+ */
+ link_set_eunatch = bpf_program__attach_cgroup(obj->progs.set_eunatch,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eunatch, "cg-attach-set_eunatch"))
+ goto close_bpf_object;
+ link_set_eisconn = bpf_program__attach_cgroup(obj->progs.set_eisconn,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eisconn, "cg-attach-set_eisconn"))
+ goto close_bpf_object;
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
+ &zero, sizeof(int)), "setsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EISCONN, "setsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 3, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, -EISCONN, "retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_set_eunatch);
+ bpf_link__destroy(link_set_eisconn);
+ bpf_link__destroy(link_get_retval);
+
+ cgroup_getset_retval_setsockopt__destroy(obj);
+}
+
+static void test_setsockopt_legacy_eperm(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_setsockopt *obj;
+ struct bpf_link *link_legacy_eperm = NULL, *link_get_retval = NULL;
+
+ obj = cgroup_getset_retval_setsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach setsockopt that return a reject without setting errno
+ * (legacy reject), and one that gets the errno. Assert that for
+ * backward compatibility the syscall result in EPERM, and this
+ * is also visible to the helper.
+ */
+ link_legacy_eperm = bpf_program__attach_cgroup(obj->progs.legacy_eperm,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_legacy_eperm, "cg-attach-legacy_eperm"))
+ goto close_bpf_object;
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
+ &zero, sizeof(int)), "setsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EPERM, "setsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 2, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, -EPERM, "retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_legacy_eperm);
+ bpf_link__destroy(link_get_retval);
+
+ cgroup_getset_retval_setsockopt__destroy(obj);
+}
+
+static void test_setsockopt_legacy_no_override(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_setsockopt *obj;
+ struct bpf_link *link_set_eunatch = NULL, *link_legacy_eperm = NULL;
+ struct bpf_link *link_get_retval = NULL;
+
+ obj = cgroup_getset_retval_setsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach setsockopt that sets EUNATCH, then one that return a reject
+ * without setting errno, and then one that gets the exported errno.
+ * Assert both the syscall and the helper's errno are unaffected by
+ * the second prog (i.e. legacy rejects does not override the errno
+ * to EPERM).
+ */
+ link_set_eunatch = bpf_program__attach_cgroup(obj->progs.set_eunatch,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eunatch, "cg-attach-set_eunatch"))
+ goto close_bpf_object;
+ link_legacy_eperm = bpf_program__attach_cgroup(obj->progs.legacy_eperm,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_legacy_eperm, "cg-attach-legacy_eperm"))
+ goto close_bpf_object;
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR,
+ &zero, sizeof(int)), "setsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EUNATCH, "setsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 3, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, -EUNATCH, "retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_set_eunatch);
+ bpf_link__destroy(link_legacy_eperm);
+ bpf_link__destroy(link_get_retval);
+
+ cgroup_getset_retval_setsockopt__destroy(obj);
+}
+
+static void test_getsockopt_get(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_getsockopt *obj;
+ struct bpf_link *link_get_retval = NULL;
+ int buf;
+ socklen_t optlen = sizeof(buf);
+
+ obj = cgroup_getset_retval_getsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach getsockopt that gets previously set errno. Assert that the
+ * error from kernel is in both ctx_retval_value and retval_value.
+ */
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(getsockopt(sock_fd, SOL_CUSTOM, 0,
+ &buf, &optlen), "getsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EOPNOTSUPP, "getsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 1, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, -EOPNOTSUPP, "retval_value"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->ctx_retval_value, -EOPNOTSUPP, "ctx_retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_get_retval);
+
+ cgroup_getset_retval_getsockopt__destroy(obj);
+}
+
+static void test_getsockopt_override(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_getsockopt *obj;
+ struct bpf_link *link_set_eisconn = NULL;
+ int buf;
+ socklen_t optlen = sizeof(buf);
+
+ obj = cgroup_getset_retval_getsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach getsockopt that sets retval to -EISCONN. Assert that this
+ * overrides the value from kernel.
+ */
+ link_set_eisconn = bpf_program__attach_cgroup(obj->progs.set_eisconn,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eisconn, "cg-attach-set_eisconn"))
+ goto close_bpf_object;
+
+ if (!ASSERT_ERR(getsockopt(sock_fd, SOL_CUSTOM, 0,
+ &buf, &optlen), "getsockopt"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(errno, EISCONN, "getsockopt-errno"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 1, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_set_eisconn);
+
+ cgroup_getset_retval_getsockopt__destroy(obj);
+}
+
+static void test_getsockopt_retval_sync(int cgroup_fd, int sock_fd)
+{
+ struct cgroup_getset_retval_getsockopt *obj;
+ struct bpf_link *link_set_eisconn = NULL, *link_clear_retval = NULL;
+ struct bpf_link *link_get_retval = NULL;
+ int buf;
+ socklen_t optlen = sizeof(buf);
+
+ obj = cgroup_getset_retval_getsockopt__open_and_load();
+ if (!ASSERT_OK_PTR(obj, "skel-load"))
+ return;
+
+ /* Attach getsockopt that sets retval to -EISCONN, and one that clears
+ * ctx retval. Assert that the clearing ctx retval is synced to helper
+ * and clears any errors both from kernel and BPF..
+ */
+ link_set_eisconn = bpf_program__attach_cgroup(obj->progs.set_eisconn,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_set_eisconn, "cg-attach-set_eisconn"))
+ goto close_bpf_object;
+ link_clear_retval = bpf_program__attach_cgroup(obj->progs.clear_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_clear_retval, "cg-attach-clear_retval"))
+ goto close_bpf_object;
+ link_get_retval = bpf_program__attach_cgroup(obj->progs.get_retval,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(link_get_retval, "cg-attach-get_retval"))
+ goto close_bpf_object;
+
+ if (!ASSERT_OK(getsockopt(sock_fd, SOL_CUSTOM, 0,
+ &buf, &optlen), "getsockopt"))
+ goto close_bpf_object;
+
+ if (!ASSERT_EQ(obj->bss->invocations, 3, "invocations"))
+ goto close_bpf_object;
+ if (!ASSERT_FALSE(obj->bss->assertion_error, "assertion_error"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->retval_value, 0, "retval_value"))
+ goto close_bpf_object;
+ if (!ASSERT_EQ(obj->bss->ctx_retval_value, 0, "ctx_retval_value"))
+ goto close_bpf_object;
+
+close_bpf_object:
+ bpf_link__destroy(link_set_eisconn);
+ bpf_link__destroy(link_clear_retval);
+ bpf_link__destroy(link_get_retval);
+
+ cgroup_getset_retval_getsockopt__destroy(obj);
+}
+
+void test_cgroup_getset_retval(void)
+{
+ int cgroup_fd = -1;
+ int sock_fd = -1;
+
+ cgroup_fd = test__join_cgroup("/cgroup_getset_retval");
+ if (!ASSERT_GE(cgroup_fd, 0, "cg-create"))
+ goto close_fd;
+
+ sock_fd = start_server(AF_INET, SOCK_DGRAM, NULL, 0, 0);
+ if (!ASSERT_GE(sock_fd, 0, "start-server"))
+ goto close_fd;
+
+ if (test__start_subtest("setsockopt-set"))
+ test_setsockopt_set(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("setsockopt-set_and_get"))
+ test_setsockopt_set_and_get(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("setsockopt-default_zero"))
+ test_setsockopt_default_zero(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("setsockopt-default_zero_and_set"))
+ test_setsockopt_default_zero_and_set(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("setsockopt-override"))
+ test_setsockopt_override(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("setsockopt-legacy_eperm"))
+ test_setsockopt_legacy_eperm(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("setsockopt-legacy_no_override"))
+ test_setsockopt_legacy_no_override(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("getsockopt-get"))
+ test_getsockopt_get(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("getsockopt-override"))
+ test_getsockopt_override(cgroup_fd, sock_fd);
+
+ if (test__start_subtest("getsockopt-retval_sync"))
+ test_getsockopt_retval_sync(cgroup_fd, sock_fd);
+
+close_fd:
+ close(cgroup_fd);
+}
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgroup_getset_retval_getsockopt.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright 2021 Google LLC.
+ */
+
+#include <errno.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+__u32 invocations = 0;
+__u32 assertion_error = 0;
+__u32 retval_value = 0;
+__u32 ctx_retval_value = 0;
+
+SEC("cgroup/getsockopt")
+int get_retval(struct bpf_sockopt *ctx)
+{
+ retval_value = bpf_get_retval();
+ ctx_retval_value = ctx->retval;
+ __sync_fetch_and_add(&invocations, 1);
+
+ return 1;
+}
+
+SEC("cgroup/getsockopt")
+int set_eisconn(struct bpf_sockopt *ctx)
+{
+ __sync_fetch_and_add(&invocations, 1);
+
+ if (bpf_set_retval(-EISCONN))
+ assertion_error = 1;
+
+ return 1;
+}
+
+SEC("cgroup/getsockopt")
+int clear_retval(struct bpf_sockopt *ctx)
+{
+ __sync_fetch_and_add(&invocations, 1);
+
+ ctx->retval = 0;
+
+ return 1;
+}
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgroup_getset_retval_setsockopt.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright 2021 Google LLC.
+ */
+
+#include <errno.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+__u32 invocations = 0;
+__u32 assertion_error = 0;
+__u32 retval_value = 0;
+
+SEC("cgroup/setsockopt")
+int get_retval(struct bpf_sockopt *ctx)
+{
+ retval_value = bpf_get_retval();
+ __sync_fetch_and_add(&invocations, 1);
+
+ return 1;
+}
+
+SEC("cgroup/setsockopt")
+int set_eunatch(struct bpf_sockopt *ctx)
+{
+ __sync_fetch_and_add(&invocations, 1);
+
+ if (bpf_set_retval(-EUNATCH))
+ assertion_error = 1;
+
+ return 0;
+}
+
+SEC("cgroup/setsockopt")
+int set_eisconn(struct bpf_sockopt *ctx)
+{
+ __sync_fetch_and_add(&invocations, 1);
+
+ if (bpf_set_retval(-EISCONN))
+ assertion_error = 1;
+
+ return 0;
+}
+
+SEC("cgroup/setsockopt")
+int legacy_eperm(struct bpf_sockopt *ctx)
+{
+ __sync_fetch_and_add(&invocations, 1);
+
+ return 0;
+}