From: Yonghong Song <yhs@fb.com>
Date: Thu, 23 Jul 2020 11:41:24 -0700
Subject: selftests/bpf: Add a test for out of bound rdonly buf access
Patch-mainline: v5.9-rc1
Git-commit: 9efcc4ad7a15ea50550c53fbf62457c309216051
References: bsc#1177028
If the bpf program contains out of bound access w.r.t. a
particular map key/value size, the verification will be
still okay, e.g., it will be accepted by verifier. But
it will be rejected during link_create time. A test
is added here to ensure link_create failure did happen
if out of bound access happened.
$ ./test_progs -n 4
...
#4/23 rdonly-buf-out-of-bound:OK
...
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184124.591700-1-yhs@fb.com
Acked-by: Gary Lin <glin@suse.com>
---
tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 22 ++++++++++
tools/testing/selftests/bpf/progs/bpf_iter_test_kern5.c | 35 ++++++++++++++++
2 files changed, 57 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_test_kern5.c
--- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
@@ -15,6 +15,7 @@
#include "bpf_iter_bpf_array_map.skel.h"
#include "bpf_iter_bpf_percpu_array_map.skel.h"
#include "bpf_iter_bpf_sk_storage_map.skel.h"
+#include "bpf_iter_test_kern5.skel.h"
static int duration;
@@ -790,6 +791,25 @@ out:
bpf_iter_bpf_sk_storage_map__destroy(skel);
}
+static void test_rdonly_buf_out_of_bound(void)
+{
+ DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
+ struct bpf_iter_test_kern5 *skel;
+ struct bpf_link *link;
+
+ skel = bpf_iter_test_kern5__open_and_load();
+ if (CHECK(!skel, "bpf_iter_test_kern5__open_and_load",
+ "skeleton open_and_load failed\n"))
+ return;
+
+ opts.map_fd = bpf_map__fd(skel->maps.hashmap1);
+ link = bpf_program__attach_iter(skel->progs.dump_bpf_hash_map, &opts);
+ if (CHECK(!IS_ERR(link), "attach_iter", "unexpected success\n"))
+ bpf_link__destroy(link);
+
+ bpf_iter_test_kern5__destroy(skel);
+}
+
void test_bpf_iter(void)
{
if (test__start_subtest("btf_id_or_null"))
@@ -826,4 +846,6 @@ void test_bpf_iter(void)
test_bpf_percpu_array_map();
if (test__start_subtest("bpf_sk_storage_map"))
test_bpf_sk_storage_map();
+ if (test__start_subtest("rdonly-buf-out-of-bound"))
+ test_rdonly_buf_out_of_bound();
}
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_test_kern5.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+#include "bpf_iter.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct key_t {
+ int a;
+ int b;
+ int c;
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 3);
+ __type(key, struct key_t);
+ __type(value, __u64);
+} hashmap1 SEC(".maps");
+
+__u32 key_sum = 0;
+
+SEC("iter/bpf_map_elem")
+int dump_bpf_hash_map(struct bpf_iter__bpf_map_elem *ctx)
+{
+ void *key = ctx->key;
+
+ if (key == (void *)0)
+ return 0;
+
+ /* out of bound access w.r.t. hashmap1 */
+ key_sum += *(__u32 *)(key + sizeof(struct key_t));
+ return 0;
+}