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0b0600c8 TH |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | ||
3 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
4 | ||
5 | #include <linux/string.h> | |
6 | ||
7 | #include "../tools/testing/selftests/kselftest_module.h" | |
8 | ||
9 | /* | |
10 | * Kernel module for testing 'strscpy' family of functions. | |
11 | */ | |
12 | ||
13 | KSTM_MODULE_GLOBALS(); | |
14 | ||
15 | /* | |
16 | * tc() - Run a specific test case. | |
17 | * @src: Source string, argument to strscpy_pad() | |
18 | * @count: Size of destination buffer, argument to strscpy_pad() | |
19 | * @expected: Expected return value from call to strscpy_pad() | |
20 | * @terminator: 1 if there should be a terminating null byte 0 otherwise. | |
21 | * @chars: Number of characters from the src string expected to be | |
22 | * written to the dst buffer. | |
23 | * @pad: Number of pad characters expected (in the tail of dst buffer). | |
24 | * (@pad does not include the null terminator byte.) | |
25 | * | |
26 | * Calls strscpy_pad() and verifies the return value and state of the | |
27 | * destination buffer after the call returns. | |
28 | */ | |
29 | static int __init tc(char *src, int count, int expected, | |
30 | int chars, int terminator, int pad) | |
31 | { | |
32 | int nr_bytes_poison; | |
33 | int max_expected; | |
34 | int max_count; | |
35 | int written; | |
36 | char buf[6]; | |
37 | int index, i; | |
38 | const char POISON = 'z'; | |
39 | ||
40 | total_tests++; | |
41 | ||
42 | if (!src) { | |
43 | pr_err("null source string not supported\n"); | |
44 | return -1; | |
45 | } | |
46 | ||
47 | memset(buf, POISON, sizeof(buf)); | |
48 | /* Future proofing test suite, validate args */ | |
49 | max_count = sizeof(buf) - 2; /* Space for null and to verify overflow */ | |
50 | max_expected = count - 1; /* Space for the null */ | |
51 | if (count > max_count) { | |
52 | pr_err("count (%d) is too big (%d) ... aborting", count, max_count); | |
53 | return -1; | |
54 | } | |
55 | if (expected > max_expected) { | |
56 | pr_warn("expected (%d) is bigger than can possibly be returned (%d)", | |
57 | expected, max_expected); | |
58 | } | |
59 | ||
60 | written = strscpy_pad(buf, src, count); | |
61 | if ((written) != (expected)) { | |
62 | pr_err("%d != %d (written, expected)\n", written, expected); | |
63 | goto fail; | |
64 | } | |
65 | ||
66 | if (count && written == -E2BIG) { | |
67 | if (strncmp(buf, src, count - 1) != 0) { | |
68 | pr_err("buffer state invalid for -E2BIG\n"); | |
69 | goto fail; | |
70 | } | |
71 | if (buf[count - 1] != '\0') { | |
72 | pr_err("too big string is not null terminated correctly\n"); | |
73 | goto fail; | |
74 | } | |
75 | } | |
76 | ||
77 | for (i = 0; i < chars; i++) { | |
78 | if (buf[i] != src[i]) { | |
79 | pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]); | |
80 | goto fail; | |
81 | } | |
82 | } | |
83 | ||
84 | if (terminator) { | |
85 | if (buf[count - 1] != '\0') { | |
86 | pr_err("string is not null terminated correctly\n"); | |
87 | goto fail; | |
88 | } | |
89 | } | |
90 | ||
91 | for (i = 0; i < pad; i++) { | |
92 | index = chars + terminator + i; | |
93 | if (buf[index] != '\0') { | |
94 | pr_err("padding missing at index: %d\n", i); | |
95 | goto fail; | |
96 | } | |
97 | } | |
98 | ||
99 | nr_bytes_poison = sizeof(buf) - chars - terminator - pad; | |
100 | for (i = 0; i < nr_bytes_poison; i++) { | |
101 | index = sizeof(buf) - 1 - i; /* Check from the end back */ | |
102 | if (buf[index] != POISON) { | |
103 | pr_err("poison value missing at index: %d\n", i); | |
104 | goto fail; | |
105 | } | |
106 | } | |
107 | ||
108 | return 0; | |
109 | fail: | |
110 | failed_tests++; | |
111 | return -1; | |
112 | } | |
113 | ||
114 | static void __init selftest(void) | |
115 | { | |
116 | /* | |
117 | * tc() uses a destination buffer of size 6 and needs at | |
118 | * least 2 characters spare (one for null and one to check for | |
119 | * overflow). This means we should only call tc() with | |
120 | * strings up to a maximum of 4 characters long and 'count' | |
121 | * should not exceed 4. To test with longer strings increase | |
122 | * the buffer size in tc(). | |
123 | */ | |
124 | ||
125 | /* tc(src, count, expected, chars, terminator, pad) */ | |
126 | KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0)); | |
127 | KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0)); | |
128 | ||
129 | KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0)); | |
130 | KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0)); | |
131 | ||
132 | KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0)); | |
133 | KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0)); | |
134 | KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1)); | |
135 | ||
136 | KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0)); | |
137 | KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0)); | |
138 | KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1)); | |
139 | KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2)); | |
140 | ||
141 | KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0)); | |
142 | KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0)); | |
143 | KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1)); | |
144 | KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2)); | |
145 | KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3)); | |
146 | } | |
147 | ||
148 | KSTM_MODULE_LOADERS(test_strscpy); | |
149 | MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>"); | |
150 | MODULE_LICENSE("GPL"); |