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 3632 2018-10-10 21:12:43Z 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;
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)->d_data);
63
64 if (e->e_rawfile == NULL) {
65 /*
66 * In the ELF_C_WRITE case, there is no source that
67 * can provide data for the section.
68 */
69 LIBELF_SET_ERROR(ARGUMENT, 0);
70 return (NULL);
71 }
72
73 elfclass = e->e_class;
74
75 assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
76
77 if (elfclass == ELFCLASS32) {
78 sh_type = s->s_shdr.s_shdr32.sh_type;
79 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
80 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
81 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
82 } else {
83 sh_type = s->s_shdr.s_shdr64.sh_type;
84 sh_offset = s->s_shdr.s_shdr64.sh_offset;
85 sh_size = s->s_shdr.s_shdr64.sh_size;
86 sh_align = s->s_shdr.s_shdr64.sh_addralign;
87 }
88
89 if (sh_type == SHT_NULL) {
90 LIBELF_SET_ERROR(SECTION, 0);
91 return (NULL);
92 }
93
94 if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
95 elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
96 (sh_offset > e->e_rawsize || sh_size > e->e_rawsize - sh_offset))) {
97 LIBELF_SET_ERROR(SECTION, 0);
98 return (NULL);
99 }
100
101 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
102 (elftype, (size_t) 1, e->e_version)) == 0) {
103 LIBELF_SET_ERROR(UNIMPL, 0);
104 return (NULL);
105 }
106
107 if (sh_size % fsz) {
108 LIBELF_SET_ERROR(SECTION, 0);
109 return (NULL);
110 }
111
112 if (sh_size / fsz > SIZE_MAX) {
113 LIBELF_SET_ERROR(RANGE, 0);
114 return (NULL);
115 }
116
117 count = (size_t) (sh_size / fsz);
118
119 msz = _libelf_msize(elftype, elfclass, e->e_version);
120
121 if (count > 0 && msz > SIZE_MAX / count) {
122 LIBELF_SET_ERROR(RANGE, 0);
123 return (NULL);
124 }
125
126 assert(msz > 0);
127 assert(count <= SIZE_MAX);
128 assert(msz * count <= SIZE_MAX);
129
130 if ((d = _libelf_allocate_data(s)) == NULL)
131 return (NULL);
132
133 d->d_data.d_buf = NULL;
134 d->d_data.d_off = 0;
135 d->d_data.d_align = sh_align;
136 d->d_data.d_size = msz * count;
137 d->d_data.d_type = elftype;
138 d->d_data.d_version = e->e_version;
139
140 if (sh_type == SHT_NOBITS || sh_size == 0) {
141 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
142 return (&d->d_data);
143 }
144
145 if ((d->d_data.d_buf = malloc(msz * count)) == NULL) {
146 (void) _libelf_release_data(d);
147 LIBELF_SET_ERROR(RESOURCE, 0);
148 return (NULL);
149 }
150
151 d->d_flags |= LIBELF_F_DATA_MALLOCED;
152
153 xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass,
154 _libelf_elfmachine(e));
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 (sh_type != SHT_NOBITS &&
257 (sh_offset > e->e_rawsize || sh_size > e->e_rawsize - sh_offset)) {
258 LIBELF_SET_ERROR(SECTION, 0);
259 return (NULL);
260 }
261
262 if ((d = _libelf_allocate_data(s)) == NULL)
263 return (NULL);
264
265 d->d_data.d_buf = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
266 e->e_rawfile + sh_offset;
267 d->d_data.d_off = 0;
268 d->d_data.d_align = sh_align;
269 d->d_data.d_size = sh_size;
270 d->d_data.d_type = ELF_T_BYTE;
271 d->d_data.d_version = e->e_version;
272
273 STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);
274
275 return (&d->d_data);
276 }
277