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 3177 2015-03-30 18:19:41Z emaste $");
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;
46 int (*xlate)(unsigned char *_d, size_t _dsz, unsigned char *_s,
47 size_t _c, int _swap);
48
49 d = (struct _Libelf_Data *) ed;
50
51 if (s == NULL || (e = s->s_elf) == NULL ||
52 (d != NULL && s != d->d_scn)) {
53 LIBELF_SET_ERROR(ARGUMENT, 0);
54 return (NULL);
55 }
56
57 assert(e->e_kind == ELF_K_ELF);
58
59 if (d == NULL && (d = STAILQ_FIRST(&s->s_data)) != NULL)
60 return (&d->d_data);
61
62 if (d != NULL)
63 return (&STAILQ_NEXT(d, d_next)->d_data);
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 if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
96 elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
97 sh_offset + sh_size > (uint64_t) e->e_rawsize)) {
98 LIBELF_SET_ERROR(SECTION, 0);
99 return (NULL);
100 }
101
102 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
103 (elftype, (size_t) 1, e->e_version)) == 0) {
104 LIBELF_SET_ERROR(UNIMPL, 0);
105 return (NULL);
106 }
107
108 if (sh_size % fsz) {
109 LIBELF_SET_ERROR(SECTION, 0);
110 return (NULL);
111 }
112
113 if (sh_size / fsz > SIZE_MAX) {
114 LIBELF_SET_ERROR(RANGE, 0);
115 return (NULL);
116 }
117
118 count = (size_t) (sh_size / fsz);
119
120 msz = _libelf_msize(elftype, elfclass, e->e_version);
121
122 if (count > 0 && msz > SIZE_MAX / count) {
123 LIBELF_SET_ERROR(RANGE, 0);
124 return (NULL);
125 }
126
127 assert(msz > 0);
128 assert(count <= SIZE_MAX);
129 assert(msz * count <= SIZE_MAX);
130
131 if ((d = _libelf_allocate_data(s)) == NULL)
132 return (NULL);
133
134 d->d_data.d_buf = NULL;
135 d->d_data.d_off = 0;
136 d->d_data.d_align = sh_align;
137 d->d_data.d_size = msz * count;
138 d->d_data.d_type = elftype;
139 d->d_data.d_version = e->e_version;
140
141 if (sh_type == SHT_NOBITS || sh_size == 0) {
142 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
143 return (&d->d_data);
144 }
145
146 if ((d->d_data.d_buf = malloc(msz * count)) == NULL) {
147 (void) _libelf_release_data(d);
148 LIBELF_SET_ERROR(RESOURCE, 0);
149 return (NULL);
150 }
151
152 d->d_flags |= LIBELF_F_DATA_MALLOCED;
153
154 xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass);
155 if (!(*xlate)(d->d_data.d_buf, (size_t) d->d_data.d_size,
156 e->e_rawfile + sh_offset, count,
157 e->e_byteorder != LIBELF_PRIVATE(byteorder))) {
158 _libelf_release_data(d);
159 LIBELF_SET_ERROR(DATA, 0);
160 return (NULL);
161 }
162
163 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
164
165 return (&d->d_data);
166 }
167
168 Elf_Data *
elf_newdata(Elf_Scn * s)169 elf_newdata(Elf_Scn *s)
170 {
171 Elf *e;
172 struct _Libelf_Data *d;
173
174 if (s == NULL || (e = s->s_elf) == NULL) {
175 LIBELF_SET_ERROR(ARGUMENT, 0);
176 return (NULL);
177 }
178
179 assert(e->e_kind == ELF_K_ELF);
180
181 /*
182 * elf_newdata() has to append a data descriptor, so
183 * bring in existing section data if not already present.
184 */
185 if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data))
186 if (elf_getdata(s, NULL) == NULL)
187 return (NULL);
188
189 if ((d = _libelf_allocate_data(s)) == NULL)
190 return (NULL);
191
192 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
193
194 d->d_data.d_align = 1;
195 d->d_data.d_buf = NULL;
196 d->d_data.d_off = (uint64_t) ~0;
197 d->d_data.d_size = 0;
198 d->d_data.d_type = ELF_T_BYTE;
199 d->d_data.d_version = LIBELF_PRIVATE(version);
200
201 (void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY);
202
203 return (&d->d_data);
204 }
205
206 /*
207 * Retrieve a data descriptor for raw (untranslated) data for section
208 * `s'.
209 */
210
211 Elf_Data *
elf_rawdata(Elf_Scn * s,Elf_Data * ed)212 elf_rawdata(Elf_Scn *s, Elf_Data *ed)
213 {
214 Elf *e;
215 int elf_class;
216 uint32_t sh_type;
217 struct _Libelf_Data *d;
218 uint64_t sh_align, sh_offset, sh_size;
219
220 if (s == NULL || (e = s->s_elf) == NULL || e->e_rawfile == NULL) {
221 LIBELF_SET_ERROR(ARGUMENT, 0);
222 return (NULL);
223 }
224
225 assert(e->e_kind == ELF_K_ELF);
226
227 d = (struct _Libelf_Data *) ed;
228
229 if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL)
230 return (&d->d_data);
231
232 if (d != NULL)
233 return (&STAILQ_NEXT(d, d_next)->d_data);
234
235 elf_class = e->e_class;
236
237 assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64);
238
239 if (elf_class == ELFCLASS32) {
240 sh_type = s->s_shdr.s_shdr32.sh_type;
241 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
242 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
243 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
244 } else {
245 sh_type = s->s_shdr.s_shdr64.sh_type;
246 sh_offset = s->s_shdr.s_shdr64.sh_offset;
247 sh_size = s->s_shdr.s_shdr64.sh_size;
248 sh_align = s->s_shdr.s_shdr64.sh_addralign;
249 }
250
251 if (sh_type == SHT_NULL) {
252 LIBELF_SET_ERROR(SECTION, 0);
253 return (NULL);
254 }
255
256 if ((d = _libelf_allocate_data(s)) == NULL)
257 return (NULL);
258
259 d->d_data.d_buf = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
260 e->e_rawfile + sh_offset;
261 d->d_data.d_off = 0;
262 d->d_data.d_align = sh_align;
263 d->d_data.d_size = sh_size;
264 d->d_data.d_type = ELF_T_BYTE;
265 d->d_data.d_version = e->e_version;
266
267 STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);
268
269 return (&d->d_data);
270 }
271