1 /*-
2 * Copyright (c) 2006,2008,2011 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <assert.h>
28 #include <errno.h>
29 #include <libelf.h>
30 #include <stdint.h>
31 #include <stdlib.h>
32
33 #include "_libelf.h"
34
35 ELFTC_VCSID("$Id: elf_data.c 3732 2019-04-22 11:08:38Z jkoshy $");
36
37 Elf_Data *
elf_getdata(Elf_Scn * s,Elf_Data * ed)38 elf_getdata(Elf_Scn *s, Elf_Data *ed)
39 {
40 Elf *e;
41 unsigned int sh_type;
42 int elfclass, elftype;
43 size_t count, fsz, msz;
44 struct _Libelf_Data *d;
45 uint64_t sh_align, sh_offset, sh_size, raw_size;
46 _libelf_translator_function *xlate;
47
48 d = (struct _Libelf_Data *) ed;
49
50 if (s == NULL || (e = s->s_elf) == NULL ||
51 (d != NULL && s != d->d_scn)) {
52 LIBELF_SET_ERROR(ARGUMENT, 0);
53 return (NULL);
54 }
55
56 assert(e->e_kind == ELF_K_ELF);
57
58 if (d == NULL && (d = STAILQ_FIRST(&s->s_data)) != NULL)
59 return (&d->d_data);
60
61 if (d != NULL)
62 return (STAILQ_NEXT(d, d_next) ?
63 &STAILQ_NEXT(d, d_next)->d_data : NULL);
64
65 if (e->e_rawfile == NULL) {
66 /*
67 * In the ELF_C_WRITE case, there is no source that
68 * can provide data for the section.
69 */
70 LIBELF_SET_ERROR(ARGUMENT, 0);
71 return (NULL);
72 }
73
74 elfclass = e->e_class;
75
76 assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
77
78 if (elfclass == ELFCLASS32) {
79 sh_type = s->s_shdr.s_shdr32.sh_type;
80 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
81 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
82 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
83 } else {
84 sh_type = s->s_shdr.s_shdr64.sh_type;
85 sh_offset = s->s_shdr.s_shdr64.sh_offset;
86 sh_size = s->s_shdr.s_shdr64.sh_size;
87 sh_align = s->s_shdr.s_shdr64.sh_addralign;
88 }
89
90 if (sh_type == SHT_NULL) {
91 LIBELF_SET_ERROR(SECTION, 0);
92 return (NULL);
93 }
94
95 raw_size = (uint64_t) e->e_rawsize;
96 if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
97 elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
98 (sh_offset > raw_size || sh_size > raw_size - sh_offset))) {
99 LIBELF_SET_ERROR(SECTION, 0);
100 return (NULL);
101 }
102
103 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
104 (elftype, (size_t) 1, e->e_version)) == 0) {
105 LIBELF_SET_ERROR(UNIMPL, 0);
106 return (NULL);
107 }
108
109 if (sh_size % fsz) {
110 LIBELF_SET_ERROR(SECTION, 0);
111 return (NULL);
112 }
113
114 if (sh_size / fsz > SIZE_MAX) {
115 LIBELF_SET_ERROR(RANGE, 0);
116 return (NULL);
117 }
118
119 count = (size_t) (sh_size / fsz);
120
121 if ((msz = _libelf_msize(elftype, elfclass, e->e_version)) == 0)
122 return (NULL);
123
124 if (count > 0 && msz > SIZE_MAX / count) {
125 LIBELF_SET_ERROR(RANGE, 0);
126 return (NULL);
127 }
128
129 assert(msz > 0);
130 assert(count <= SIZE_MAX);
131 assert(msz * count <= SIZE_MAX);
132
133 if ((d = _libelf_allocate_data(s)) == NULL)
134 return (NULL);
135
136 d->d_data.d_buf = NULL;
137 d->d_data.d_off = 0;
138 d->d_data.d_align = sh_align;
139 d->d_data.d_size = msz * count;
140 d->d_data.d_type = elftype;
141 d->d_data.d_version = e->e_version;
142
143 if (sh_type == SHT_NOBITS || sh_size == 0) {
144 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
145 return (&d->d_data);
146 }
147
148 if ((d->d_data.d_buf = malloc(msz * count)) == NULL) {
149 (void) _libelf_release_data(d);
150 LIBELF_SET_ERROR(RESOURCE, 0);
151 return (NULL);
152 }
153
154 d->d_flags |= LIBELF_F_DATA_MALLOCED;
155
156 xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass,
157 _libelf_elfmachine(e));
158 if (!(*xlate)(d->d_data.d_buf, (size_t) d->d_data.d_size,
159 e->e_rawfile + sh_offset, count,
160 e->e_byteorder != LIBELF_PRIVATE(byteorder))) {
161 _libelf_release_data(d);
162 LIBELF_SET_ERROR(DATA, 0);
163 return (NULL);
164 }
165
166 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
167
168 return (&d->d_data);
169 }
170
171 Elf_Data *
elf_newdata(Elf_Scn * s)172 elf_newdata(Elf_Scn *s)
173 {
174 Elf *e;
175 struct _Libelf_Data *d;
176
177 if (s == NULL || (e = s->s_elf) == NULL) {
178 LIBELF_SET_ERROR(ARGUMENT, 0);
179 return (NULL);
180 }
181
182 assert(e->e_kind == ELF_K_ELF);
183
184 /*
185 * elf_newdata() has to append a data descriptor, so
186 * bring in existing section data if not already present.
187 */
188 if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data))
189 if (elf_getdata(s, NULL) == NULL)
190 return (NULL);
191
192 if ((d = _libelf_allocate_data(s)) == NULL)
193 return (NULL);
194
195 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
196
197 d->d_data.d_align = 1;
198 d->d_data.d_buf = NULL;
199 d->d_data.d_off = (uint64_t) ~0;
200 d->d_data.d_size = 0;
201 d->d_data.d_type = ELF_T_BYTE;
202 d->d_data.d_version = LIBELF_PRIVATE(version);
203
204 (void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY);
205
206 return (&d->d_data);
207 }
208
209 /*
210 * Retrieve a data descriptor for raw (untranslated) data for section
211 * `s'.
212 */
213
214 Elf_Data *
elf_rawdata(Elf_Scn * s,Elf_Data * ed)215 elf_rawdata(Elf_Scn *s, Elf_Data *ed)
216 {
217 Elf *e;
218 int elf_class;
219 uint32_t sh_type;
220 struct _Libelf_Data *d;
221 uint64_t sh_align, sh_offset, sh_size, raw_size;
222
223 if (s == NULL || (e = s->s_elf) == NULL || e->e_rawfile == NULL) {
224 LIBELF_SET_ERROR(ARGUMENT, 0);
225 return (NULL);
226 }
227
228 assert(e->e_kind == ELF_K_ELF);
229
230 d = (struct _Libelf_Data *) ed;
231
232 if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL)
233 return (&d->d_data);
234
235 if (d != NULL)
236 return (&STAILQ_NEXT(d, d_next)->d_data);
237
238 elf_class = e->e_class;
239
240 assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64);
241
242 if (elf_class == ELFCLASS32) {
243 sh_type = s->s_shdr.s_shdr32.sh_type;
244 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
245 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
246 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
247 } else {
248 sh_type = s->s_shdr.s_shdr64.sh_type;
249 sh_offset = s->s_shdr.s_shdr64.sh_offset;
250 sh_size = s->s_shdr.s_shdr64.sh_size;
251 sh_align = s->s_shdr.s_shdr64.sh_addralign;
252 }
253
254 if (sh_type == SHT_NULL) {
255 LIBELF_SET_ERROR(SECTION, 0);
256 return (NULL);
257 }
258
259 raw_size = (uint64_t) e->e_rawsize;
260 if (sh_type != SHT_NOBITS &&
261 (sh_offset > raw_size || sh_size > raw_size - sh_offset)) {
262 LIBELF_SET_ERROR(SECTION, 0);
263 return (NULL);
264 }
265
266 if ((d = _libelf_allocate_data(s)) == NULL)
267 return (NULL);
268
269 d->d_data.d_buf = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
270 e->e_rawfile + sh_offset;
271 d->d_data.d_off = 0;
272 d->d_data.d_align = sh_align;
273 d->d_data.d_size = sh_size;
274 d->d_data.d_type = ELF_T_BYTE;
275 d->d_data.d_version = e->e_version;
276
277 STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);
278
279 return (&d->d_data);
280 }
281