1 /* $NetBSD: symver.c,v 1.4 2013/05/09 15:38:14 christos Exp $ */
2
3 /*-
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: head/libexec/rtld-elf/rtld.c 220004 2011-03-25 18:23:10Z avg $
30 */
31
32 /*-
33 * Copyright (c) 2011 The NetBSD Foundation, Inc.
34 * All rights reserved.
35 *
36 * This code is derived from software contributed to The NetBSD Foundation
37 * by NONAKA Kimihiro.
38 *
39 * Redistribution and use in source and binary forms, with or without
40 * modification, are permitted provided that the following conditions
41 * are met:
42 * 1. Redistributions of source code must retain the above copyright
43 * notice, this list of conditions and the following disclaimer.
44 * 2. Redistributions in binary form must reproduce the above copyright
45 * notice, this list of conditions and the following disclaimer in the
46 * documentation and/or other materials provided with the distribution.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
49 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
50 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
51 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
52 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
53 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
54 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
55 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
56 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
57 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
58 * POSSIBILITY OF SUCH DAMAGE.
59 */
60
61 #include <sys/cdefs.h>
62 __RCSID("$NetBSD: symver.c,v 1.4 2013/05/09 15:38:14 christos Exp $");
63
64 #include <sys/param.h>
65 #include <sys/exec_elf.h>
66 #include <string.h>
67
68 #include "debug.h"
69 #include "rtld.h"
70
71 void
_rtld_object_add_name(Obj_Entry * obj,const char * name)72 _rtld_object_add_name(Obj_Entry *obj, const char *name)
73 {
74 Name_Entry *entry;
75 size_t len;
76
77 len = strlen(name);
78 entry = xmalloc(sizeof(Name_Entry) + len);
79
80 if (entry != NULL) {
81 strcpy(entry->name, name);
82 SIMPLEQ_INSERT_TAIL(&obj->names, entry, link);
83 }
84 }
85
86 int
_rtld_object_match_name(const Obj_Entry * obj,const char * name)87 _rtld_object_match_name(const Obj_Entry *obj, const char *name)
88 {
89 Name_Entry *entry;
90
91 SIMPLEQ_FOREACH(entry, &obj->names, link) {
92 dbg(("name: %s, entry->name: %s", name, entry->name));
93 if (strcmp(name, entry->name) == 0)
94 return 1;
95 }
96 return 0;
97 }
98
99 #ifdef RTLD_LOADER
100 static Obj_Entry *
locate_dependency(const Obj_Entry * obj,const char * name)101 locate_dependency(const Obj_Entry *obj, const char *name)
102 {
103 const Objlist_Entry *entry;
104 const Needed_Entry *needed;
105
106 SIMPLEQ_FOREACH(entry, &_rtld_list_main, link) {
107 if (_rtld_object_match_name(entry->obj, name))
108 return entry->obj;
109 }
110
111 for (needed = obj->needed; needed != NULL; needed = needed->next) {
112 dbg(("needed: name: %s, str: %s", name,
113 &obj->strtab[needed->name]));
114 if (strcmp(name, &obj->strtab[needed->name]) == 0 ||
115 (needed->obj != NULL && _rtld_object_match_name(needed->obj, name))) {
116 /*
117 * If there is DT_NEEDED for the name we are looking
118 * for, we are all set. Note that object might not be
119 * found if dependency was not loaded yet, so the
120 * function can return NULL here. This is expected
121 * and handled properly by the caller.
122 */
123 return needed->obj;
124 }
125 }
126
127 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
128 obj->path, name);
129 return NULL;
130 }
131
132 static int
check_object_provided_version(Obj_Entry * refobj,const Obj_Entry * depobj,const Elf_Vernaux * vna)133 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
134 const Elf_Vernaux *vna)
135 {
136 const char *vername = &refobj->strtab[vna->vna_name];
137 const char *depstrtab = depobj->strtab;
138 const Elf_Verdef *vd = depobj->verdef;
139 const Elf_Word hash = vna->vna_hash;
140
141 if (vd == NULL) {
142 _rtld_error("%s: version %s required by %s not defined",
143 depobj->path, vername, refobj->path);
144 return -1;
145 }
146
147 for (;; vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next)) {
148 if (vd->vd_version != VER_DEF_CURRENT) {
149 _rtld_error(
150 "%s: Unsupported version %d of Elf_Verdef entry",
151 depobj->path, vd->vd_version);
152 return -1;
153 }
154 dbg(("hash: 0x%x, vd_hash: 0x%x", hash, vd->vd_hash));
155 if (hash == vd->vd_hash) {
156 const Elf_Verdaux *vda = (const Elf_Verdaux *)
157 ((const char *)vd + vd->vd_aux);
158 dbg(("vername: %s, str: %s", vername,
159 &depstrtab[vda->vda_name]));
160 if (strcmp(vername, &depstrtab[vda->vda_name]) == 0)
161 return 0;
162 }
163 if (vd->vd_next == 0)
164 break;
165 }
166 if (vna->vna_flags & VER_FLG_WEAK)
167 return 0;
168
169 _rtld_error("%s: version %s required by %s not found", depobj->path,
170 vername, refobj->path);
171 return -1;
172 }
173
174 int
_rtld_verify_object_versions(Obj_Entry * obj)175 _rtld_verify_object_versions(Obj_Entry *obj)
176 {
177 const char *strtab = obj->strtab;
178 const Elf_Verneed *vn;
179 const Elf_Vernaux *vna;
180 const Elf_Verdef *vd;
181 const Elf_Verdaux *vda;
182 const Obj_Entry *depobj;
183 int maxvertab, vernum;
184
185 dbg(("obj->path: %s", obj->path));
186
187 /*
188 * If we don't have string table or objects that have their version
189 * requirements already checked, we must be ok.
190 */
191 if (strtab == NULL || obj->vertab != NULL)
192 return 0;
193
194 maxvertab = 0;
195
196 /*
197 * Walk over defined and required version records and figure out
198 * max index used by any of them. Do very basic sanity checking
199 * while there.
200 */
201 for (vn = obj->verneed;
202 vn != NULL;
203 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next)) {
204
205 if (vn->vn_version != VER_NEED_CURRENT) {
206 _rtld_error(
207 "%s: Unsupported version %d of Elf_Verneed entry",
208 obj->path, vn->vn_version);
209 return -1;
210 }
211
212 dbg(("verneed: vn_file: %d, str: %s",
213 vn->vn_file, &strtab[vn->vn_file]));
214 depobj = locate_dependency(obj, &strtab[vn->vn_file]);
215 assert(depobj != NULL);
216
217 for (vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
218 /*CONSTCOND*/1;
219 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next)) {
220
221 if (check_object_provided_version(obj, depobj, vna) == -1)
222 return -1;
223
224 vernum = VER_NEED_IDX(vna->vna_other);
225 if (vernum > maxvertab)
226 maxvertab = vernum;
227
228 if (vna->vna_next == 0) {
229 /* No more symbols. */
230 break;
231 }
232 }
233
234 if (vn->vn_next == 0) {
235 /* No more dependencies. */
236 break;
237 }
238 }
239
240 for (vd = obj->verdef;
241 vd != NULL;
242 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next)) {
243
244 if (vd->vd_version != VER_DEF_CURRENT) {
245 _rtld_error(
246 "%s: Unsupported version %d of Elf_Verdef entry",
247 obj->path, vd->vd_version);
248 return -1;
249 }
250
251 dbg(("verdef: vn_ndx: 0x%x", vd->vd_ndx));
252 vernum = VER_DEF_IDX(vd->vd_ndx);
253 if (vernum > maxvertab)
254 maxvertab = vernum;
255
256 if (vd->vd_next == 0) {
257 /* No more definitions. */
258 break;
259 }
260 }
261
262 dbg(("maxvertab: %d", maxvertab));
263 if (maxvertab == 0)
264 return 0;
265
266 /*
267 * Store version information in array indexable by version index.
268 * Verify that object version requirements are satisfied along the
269 * way.
270 */
271 obj->vertabnum = maxvertab + 1;
272 obj->vertab = (Ver_Entry *)xcalloc(obj->vertabnum * sizeof(Ver_Entry));
273
274 for (vn = obj->verneed;
275 vn != NULL;
276 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next)) {
277
278 for (vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
279 /*CONSTCOND*/1;
280 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next)) {
281
282 vernum = VER_NEED_IDX(vna->vna_other);
283 assert(vernum <= maxvertab);
284 obj->vertab[vernum].hash = vna->vna_hash;
285 obj->vertab[vernum].name = &strtab[vna->vna_name];
286 obj->vertab[vernum].file = &strtab[vn->vn_file];
287 obj->vertab[vernum].flags =
288 (vna->vna_other & VER_NEED_HIDDEN)
289 ? VER_INFO_HIDDEN : 0;
290 dbg(("verneed: vernum: %d, hash: 0x%x, name: %s, "
291 "file: %s, flags: 0x%x", vernum,
292 obj->vertab[vernum].hash, obj->vertab[vernum].name,
293 obj->vertab[vernum].file,
294 obj->vertab[vernum].flags));
295
296 if (vna->vna_next == 0) {
297 /* No more symbols. */
298 break;
299 }
300 }
301 if (vn->vn_next == 0) {
302 /* No more dependencies. */
303 break;
304 }
305 }
306
307 for (vd = obj->verdef;
308 vd != NULL;
309 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next)) {
310
311 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
312 vernum = VER_DEF_IDX(vd->vd_ndx);
313 assert(vernum <= maxvertab);
314 vda = (const Elf_Verdaux *)
315 ((const char *)vd + vd->vd_aux);
316 obj->vertab[vernum].hash = vd->vd_hash;
317 obj->vertab[vernum].name = &strtab[vda->vda_name];
318 obj->vertab[vernum].file = NULL;
319 obj->vertab[vernum].flags = 0;
320 dbg(("verdef: vernum: %d, hash: 0x%x, name: %s",
321 vernum, obj->vertab[vernum].hash,
322 obj->vertab[vernum].name));
323 }
324
325 if (vd->vd_next == 0) {
326 /* No more definitions. */
327 break;
328 }
329 }
330
331 return 0;
332 }
333 #endif
334