projects/linux·blob master · refs

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1// SPDX-License-Identifier: GPL-2.0
2#include <test_progs.h>
3
4/*
5 * Test that replacing an inner percpu array map with one that has different
6 * max_entries is rejected. percpu_array_map_gen_lookup() inlines the
7 * template's index_mask, so allowing a smaller replacement would cause OOB.
8 */
9void test_percpu_array_inner_map(void)
10{
11 LIBBPF_OPTS(bpf_map_create_opts, opts);
12 int outer_fd, tmpl_fd, good_fd, bad_fd, err;
13 int zero = 0;
14
15 /* Create template: percpu array with 8 entries */
16 tmpl_fd = bpf_map_create(BPF_MAP_TYPE_PERCPU_ARRAY, "tmpl",
17 sizeof(int), sizeof(long), 8, NULL);
18 if (!ASSERT_OK_FD(tmpl_fd, "create_tmpl"))
19 return;
20
21 /* Create outer array-of-maps using template */
22 opts.inner_map_fd = tmpl_fd;
23 outer_fd = bpf_map_create(BPF_MAP_TYPE_ARRAY_OF_MAPS, "outer",
24 sizeof(int), sizeof(int), 1, &opts);
25 if (!ASSERT_OK_FD(outer_fd, "create_outer"))
26 goto close_tmpl;
27
28 /* Insert template as initial inner map */
29 err = bpf_map_update_elem(outer_fd, &zero, &tmpl_fd, 0);
30 if (!ASSERT_OK(err, "insert_tmpl"))
31 goto close_outer;
32
33 /* Replacement with same max_entries should succeed */
34 good_fd = bpf_map_create(BPF_MAP_TYPE_PERCPU_ARRAY, "good",
35 sizeof(int), sizeof(long), 8, NULL);
36 if (!ASSERT_OK_FD(good_fd, "create_good"))
37 goto close_outer;
38
39 err = bpf_map_update_elem(outer_fd, &zero, &good_fd, 0);
40 ASSERT_OK(err, "replace_same_max_entries");
41 close(good_fd);
42
43 /* Replacement with fewer max_entries must fail */
44 bad_fd = bpf_map_create(BPF_MAP_TYPE_PERCPU_ARRAY, "bad",
45 sizeof(int), sizeof(long), 2, NULL);
46 if (!ASSERT_OK_FD(bad_fd, "create_bad"))
47 goto close_outer;
48
49 err = bpf_map_update_elem(outer_fd, &zero, &bad_fd, 0);
50 ASSERT_ERR(err, "replace_smaller_max_entries");
51 close(bad_fd);
52
53close_outer:
54 close(outer_fd);
55close_tmpl:
56 close(tmpl_fd);
57}