1/*	$NetBSD: symver.c,v 1.3 2013/05/07 13:01:07 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 1.3 2013/05/07 13:01:07 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
71void
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
86int
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
100static Obj_Entry *
101locate_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
132static int
133check_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
174int
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