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1 | /* Test for bug 17079: heap overflow in NSS with small buffers. | |
2 | Copyright (C) 2015-2018 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <errno.h> | |
20 | #include <nss.h> | |
21 | #include <pwd.h> | |
22 | #include <stdbool.h> | |
23 | #include <stdio.h> | |
24 | #include <stdlib.h> | |
25 | #include <string.h> | |
26 | ||
27 | #include <support/support.h> | |
28 | ||
29 | /* Check if two passwd structs contain the same data. */ | |
30 | static bool | |
31 | equal (const struct passwd *a, const struct passwd *b) | |
32 | { | |
33 | return strcmp (a->pw_name, b->pw_name) == 0 | |
34 | && strcmp (a->pw_passwd, b->pw_passwd) == 0 | |
35 | && a->pw_uid == b->pw_uid | |
36 | && a->pw_gid == b->pw_gid | |
37 | && strcmp (a->pw_gecos, b->pw_gecos) == 0 | |
38 | && strcmp (a->pw_dir, b->pw_dir) == 0 | |
39 | && strcmp (a->pw_shell, b->pw_shell) == 0; | |
40 | } | |
41 | ||
42 | enum { MAX_TEST_ITEMS = 10 }; | |
43 | static struct passwd test_items[MAX_TEST_ITEMS]; | |
44 | static int test_count; | |
45 | ||
46 | /* Initialize test_items and test_count above, with data from the | |
47 | passwd database. */ | |
48 | static bool | |
49 | init_test_items (void) | |
50 | { | |
51 | setpwent (); | |
52 | do | |
53 | { | |
54 | struct passwd *pwd = getpwent (); | |
55 | if (pwd == NULL) | |
56 | break; | |
57 | struct passwd *target = test_items + test_count; | |
58 | target->pw_name = xstrdup (pwd->pw_name); | |
59 | target->pw_passwd = xstrdup (pwd->pw_passwd); | |
60 | target->pw_uid = pwd->pw_uid; | |
61 | target->pw_gid = pwd->pw_gid; | |
62 | target->pw_gecos = xstrdup (pwd->pw_gecos); | |
63 | target->pw_dir = xstrdup (pwd->pw_dir); | |
64 | target->pw_shell = xstrdup (pwd->pw_shell); | |
65 | } | |
66 | while (++test_count < MAX_TEST_ITEMS); | |
67 | endpwent (); | |
68 | ||
69 | /* Filter out those test items which cannot be looked up by name or | |
70 | UID. */ | |
71 | bool found = false; | |
72 | for (int i = 0; i < test_count; ++i) | |
73 | { | |
74 | struct passwd *pwd1 = getpwnam (test_items[i].pw_name); | |
75 | struct passwd *pwd2 = getpwuid (test_items[i].pw_uid); | |
76 | if (pwd1 == NULL || !equal (pwd1, test_items + i) | |
77 | || pwd2 == NULL || !equal (pwd2, test_items + i)) | |
78 | { | |
79 | printf ("info: skipping user \"%s\", UID %ld due to inconsistency\n", | |
80 | test_items[i].pw_name, (long) test_items[i].pw_uid); | |
81 | test_items[i].pw_name = NULL; | |
82 | } | |
83 | else | |
84 | found = true; | |
85 | } | |
86 | ||
87 | if (!found) | |
88 | puts ("error: no accounts found which can be looked up by name and UID."); | |
89 | return found; | |
90 | } | |
91 | ||
92 | /* Set to true if an error is encountered. */ | |
93 | static bool errors; | |
94 | ||
95 | /* Return true if the padding has not been tampered with. */ | |
96 | static bool | |
97 | check_padding (char *buffer, size_t size, char pad) | |
98 | { | |
99 | char *end = buffer + size; | |
100 | while (buffer < end) | |
101 | { | |
102 | if (*buffer != pad) | |
103 | return false; | |
104 | ++buffer; | |
105 | } | |
106 | return true; | |
107 | } | |
108 | ||
109 | /* Test one buffer size and padding combination. */ | |
110 | static void | |
111 | test_one (const struct passwd *item, size_t buffer_size, | |
112 | char pad, size_t padding_size) | |
113 | { | |
114 | char *buffer = xmalloc (buffer_size + padding_size); | |
115 | ||
116 | struct passwd pwd; | |
117 | struct passwd *result; | |
118 | int ret; | |
119 | ||
120 | /* Test getpwname_r. */ | |
121 | memset (buffer, pad, buffer_size + padding_size); | |
122 | pwd = (struct passwd) {}; | |
123 | ret = getpwnam_r (item->pw_name, &pwd, buffer, buffer_size, &result); | |
124 | if (!check_padding (buffer + buffer_size, padding_size, pad)) | |
125 | { | |
126 | printf ("error: padding change: " | |
127 | "name \"%s\", buffer size %zu, padding size %zu, pad 0x%02x\n", | |
128 | item->pw_name, buffer_size, padding_size, (unsigned char) pad); | |
129 | errors = true; | |
130 | } | |
131 | if (ret == 0) | |
132 | { | |
133 | if (result == NULL) | |
134 | { | |
135 | printf ("error: no data: name \"%s\", buffer size %zu\n", | |
136 | item->pw_name, buffer_size); | |
137 | errors = true; | |
138 | } | |
139 | else if (!equal (item, result)) | |
140 | { | |
141 | printf ("error: lookup mismatch: name \"%s\", buffer size %zu\n", | |
142 | item->pw_name, buffer_size); | |
143 | errors = true; | |
144 | } | |
145 | } | |
146 | else if (ret != ERANGE) | |
147 | { | |
148 | errno = ret; | |
149 | printf ("error: lookup failure for name \"%s\": %m (%d)\n", | |
150 | item->pw_name, ret); | |
151 | errors = true; | |
152 | } | |
153 | ||
154 | /* Test getpwuid_r. */ | |
155 | memset (buffer, pad, buffer_size + padding_size); | |
156 | pwd = (struct passwd) {}; | |
157 | ret = getpwuid_r (item->pw_uid, &pwd, buffer, buffer_size, &result); | |
158 | if (!check_padding (buffer + buffer_size, padding_size, pad)) | |
159 | { | |
160 | printf ("error: padding change: " | |
161 | "UID %ld, buffer size %zu, padding size %zu, pad 0x%02x\n", | |
162 | (long) item->pw_uid, buffer_size, padding_size, | |
163 | (unsigned char) pad); | |
164 | errors = true; | |
165 | } | |
166 | if (ret == 0) | |
167 | { | |
168 | if (result == NULL) | |
169 | { | |
170 | printf ("error: no data: UID %ld, buffer size %zu\n", | |
171 | (long) item->pw_uid, buffer_size); | |
172 | errors = true; | |
173 | } | |
174 | else if (!equal (item, result)) | |
175 | { | |
176 | printf ("error: lookup mismatch: UID %ld, buffer size %zu\n", | |
177 | (long) item->pw_uid, buffer_size); | |
178 | errors = true; | |
179 | } | |
180 | } | |
181 | else if (ret != ERANGE) | |
182 | { | |
183 | errno = ret; | |
184 | printf ("error: lookup failure for UID \"%ld\": %m (%d)\n", | |
185 | (long) item->pw_uid, ret); | |
186 | errors = true; | |
187 | } | |
188 | ||
189 | free (buffer); | |
190 | } | |
191 | ||
192 | /* Test one buffer size with different paddings. */ | |
193 | static void | |
194 | test_buffer_size (size_t buffer_size) | |
195 | { | |
196 | for (int i = 0; i < test_count; ++i) | |
197 | for (size_t padding_size = 0; padding_size < 3; ++padding_size) | |
198 | { | |
199 | /* Skip entries with inconsistent name/UID lookups. */ | |
200 | if (test_items[i].pw_name == NULL) | |
201 | continue; | |
202 | ||
203 | test_one (test_items + i, buffer_size, '\0', padding_size); | |
204 | if (padding_size > 0) | |
205 | { | |
206 | test_one (test_items + i, buffer_size, ':', padding_size); | |
207 | test_one (test_items + i, buffer_size, '\n', padding_size); | |
208 | test_one (test_items + i, buffer_size, '\xff', padding_size); | |
209 | test_one (test_items + i, buffer_size, '@', padding_size); | |
210 | } | |
211 | } | |
212 | } | |
213 | ||
214 | int | |
215 | do_test (void) | |
216 | { | |
217 | __nss_configure_lookup ("passwd", "files"); | |
218 | ||
219 | if (!init_test_items ()) | |
220 | return 1; | |
221 | printf ("info: %d test items\n", test_count); | |
222 | ||
223 | for (size_t buffer_size = 0; buffer_size <= 65; ++buffer_size) | |
224 | test_buffer_size (buffer_size); | |
225 | for (size_t buffer_size = 64 + 4; buffer_size < 256; buffer_size += 4) | |
226 | test_buffer_size (buffer_size); | |
227 | test_buffer_size (255); | |
228 | test_buffer_size (257); | |
229 | for (size_t buffer_size = 256; buffer_size < 512; buffer_size += 8) | |
230 | test_buffer_size (buffer_size); | |
231 | test_buffer_size (511); | |
232 | test_buffer_size (513); | |
233 | test_buffer_size (1024); | |
234 | test_buffer_size (2048); | |
235 | ||
236 | if (errors) | |
237 | return 1; | |
238 | else | |
239 | return 0; | |
240 | } | |
241 | ||
242 | #include <support/test-driver.c> |