Adding new prog_tests for sysctl BPF handlers, first version with
a single test to validate bpf_sysctl_set_new_value call
Signed-off-by: Raman Shukhau <ramasha@xxxxxxxx>
---
.../selftests/bpf/prog_tests/cgrp_sysctl.c | 106 ++++++++++++++++++
.../testing/selftests/bpf/progs/cgrp_sysctl.c | 51 +++++++++
2 files changed, 157 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/cgrp_sysctl.c
create mode 100644 tools/testing/selftests/bpf/progs/cgrp_sysctl.c
diff --git a/tools/testing/selftests/bpf/prog_tests/cgrp_sysctl.c b/tools/testing/selftests/bpf/prog_tests/cgrp_sysctl.c
new file mode 100644
index 000000000000..dad847d397de
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgrp_sysctl.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright 2022 Google LLC.
+ */
+
+#define SYSCTL_ROOT_PATH "/proc/sys/"
+#define SYSCTL_NAME_LEN 128
+#define RESERVED_PORTS_SYSCTL_NAME "net/ipv4/ip_local_reserved_ports"
+#define RESERVED_PORTS_OVERRIDE_VALUE "31337"
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include <sys/mount.h>
+
+#include "test_progs.h"
+#include "cgrp_sysctl.skel.h"
+
+struct sysctl_test {
+ const char *sysctl;
+ int open_flags;
+ const char *newval;
+ const char *updval;
+};
+
+static void subtest(int cgroup_fd, struct cgrp_sysctl *skel, struct sysctl_test *test_data)
+{
+ int fd;
+
+ fd = open(SYSCTL_ROOT_PATH RESERVED_PORTS_SYSCTL_NAME, test_data->open_flags | O_CLOEXEC);
+ if (!ASSERT_GT(fd, 0, "sysctl-open"))
+ return;
+
+ if (test_data->open_flags == O_RDWR) {
+ int wr_ret;
+
+ wr_ret = write(fd, test_data->newval, strlen(test_data->newval));
+ if (!ASSERT_GT(wr_ret, 0, "sysctl-write"))
+ goto out;
+
+ char buf[SYSCTL_NAME_LEN];
+ char updval[SYSCTL_NAME_LEN];
+
+ sprintf(updval, "%s\n", test_data->updval);
+ if (!ASSERT_OK(lseek(fd, 0, SEEK_SET), "sysctl-seek"))
+ goto out;
+ if (!ASSERT_GT(read(fd, buf, sizeof(buf)), 0, "sysctl-read"))
+ goto out;
+ if (!ASSERT_OK(strncmp(buf, updval, strlen(updval)), "sysctl-updval"))
+ goto out;
+ }
+
+out:
+ close(fd);
+}
+
+void test_cgrp_sysctl(void)
+{
+ struct cgrp_sysctl *skel;
+ int cgroup_fd;
+
+ cgroup_fd = test__join_cgroup("/cgrp_sysctl");
+ if (!ASSERT_GE(cgroup_fd, 0, "cg-create"))
+ return;
+
+ skel = cgrp_sysctl__open();
+ if (!ASSERT_OK_PTR(skel, "skel-open"))
+ goto close_cgroup;
+
+ struct sysctl_test test_data;
+
+ if (test__start_subtest("overwrite_success")) {
+ test_data = (struct sysctl_test){
+ .sysctl = RESERVED_PORTS_SYSCTL_NAME,
+ .open_flags = O_RDWR,
+ .newval = "22222",
+ .updval = RESERVED_PORTS_OVERRIDE_VALUE,
+ };
+ memcpy(skel->rodata->sysctl_name, RESERVED_PORTS_SYSCTL_NAME,
+ sizeof(RESERVED_PORTS_SYSCTL_NAME));
+ skel->rodata->name_len = sizeof(RESERVED_PORTS_SYSCTL_NAME);
+ memcpy(skel->rodata->sysctl_updval, RESERVED_PORTS_OVERRIDE_VALUE,
+ sizeof(RESERVED_PORTS_OVERRIDE_VALUE));
+ skel->rodata->updval_len = sizeof(RESERVED_PORTS_OVERRIDE_VALUE);
+ }
+
+ if (!ASSERT_OK(cgrp_sysctl__load(skel), "skel-load"))
+ goto close_cgroup;
+
+ skel->links.cgrp_sysctl_overwrite =
+ bpf_program__attach_cgroup(skel->progs.cgrp_sysctl_overwrite, cgroup_fd);
+ if (!ASSERT_OK_PTR(skel->links.cgrp_sysctl_overwrite, "cg-attach-sysctl"))
+ goto skel_destroy;
+
+ subtest(cgroup_fd, skel, &test_data);
+ goto skel_destroy;
+
+skel_destroy:
+ cgrp_sysctl__destroy(skel);
+
+close_cgroup:
+ close(cgroup_fd);
+}
diff --git a/tools/testing/selftests/bpf/progs/cgrp_sysctl.c b/tools/testing/selftests/bpf/progs/cgrp_sysctl.c
new file mode 100644
index 000000000000..99b202835f85
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgrp_sysctl.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+
+#include <string.h>
+#include <stdbool.h>
+
+#include <linux/bpf.h>
+
+#include <bpf/bpf_helpers.h>
+
+#include "bpf_compiler.h"
+
+#define SYSCTL_VALUE_LEN 16
+#define SYSCTL_NAME_LEN 128
+
+#define SUCCESS 1
+#define FAILURE 0
+
+const char sysctl_updval[SYSCTL_VALUE_LEN];
+volatile const unsigned int updval_len;
+const char sysctl_name[SYSCTL_NAME_LEN];
+volatile const unsigned int name_len;
+
+static __always_inline bool is_expected_name(struct bpf_sysctl *ctx)
+{
+ char name[SYSCTL_NAME_LEN];
+ int size;
+
+ memset(name, 0, sizeof(name));
+ size = bpf_sysctl_get_name(ctx, name, sizeof(name), 0);
+ if (size <= 0 || size != name_len - 1)
+ return 1;
+
+ return bpf_strncmp(name, size, (const char *)sysctl_name) == 0;
+}
+
+SEC("cgroup/sysctl")
+int cgrp_sysctl_overwrite(struct bpf_sysctl *ctx)
+{
+ if (!ctx->write)
+ return SUCCESS;
+
+ if (!is_expected_name(ctx))
+ return SUCCESS;
+
+ if (bpf_sysctl_set_new_value(ctx, (char *)sysctl_updval, updval_len) == 0)
+ return SUCCESS;
+ return FAILURE;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.43.0
