1 /*-
2 * Copyright (c) 2006,2008 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 <gelf.h>
29 #include <libelf.h>
30 #include <stdlib.h>
31
32 #include "_libelf.h"
33
34 ELFTC_VCSID("$Id: libelf_phdr.c 3732 2019-04-22 11:08:38Z jkoshy $");
35
36 void *
_libelf_getphdr(Elf * e,int ec)37 _libelf_getphdr(Elf *e, int ec)
38 {
39 size_t phnum;
40 size_t fsz, msz;
41 uint64_t phoff;
42 Elf32_Ehdr *eh32;
43 Elf64_Ehdr *eh64;
44 void *ehdr, *phdr;
45 _libelf_translator_function *xlator;
46
47 assert(ec == ELFCLASS32 || ec == ELFCLASS64);
48
49 if (e == NULL) {
50 LIBELF_SET_ERROR(ARGUMENT, 0);
51 return (NULL);
52 }
53
54 if ((phdr = (ec == ELFCLASS32 ?
55 (void *) e->e_u.e_elf.e_phdr.e_phdr32 :
56 (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL)
57 return (phdr);
58
59 /*
60 * Check the PHDR related fields in the EHDR for sanity.
61 */
62
63 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
64 return (NULL);
65
66 phnum = e->e_u.e_elf.e_nphdr;
67
68 if (ec == ELFCLASS32) {
69 eh32 = (Elf32_Ehdr *) ehdr;
70 phoff = (uint64_t) eh32->e_phoff;
71 } else {
72 eh64 = (Elf64_Ehdr *) ehdr;
73 phoff = (uint64_t) eh64->e_phoff;
74 }
75
76 fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version);
77
78 assert(fsz > 0);
79
80 if (phoff + fsz < phoff) { /* Numeric overflow. */
81 LIBELF_SET_ERROR(HEADER, 0);
82 return (NULL);
83 }
84
85 if ((uint64_t) e->e_rawsize < (phoff + fsz)) {
86 LIBELF_SET_ERROR(HEADER, 0);
87 return (NULL);
88 }
89
90 if ((msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT)) == 0)
91 return (NULL);
92
93 if ((phdr = calloc(phnum, msz)) == NULL) {
94 LIBELF_SET_ERROR(RESOURCE, 0);
95 return (NULL);
96 }
97
98 if (ec == ELFCLASS32)
99 e->e_u.e_elf.e_phdr.e_phdr32 = phdr;
100 else
101 e->e_u.e_elf.e_phdr.e_phdr64 = phdr;
102
103
104 xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec,
105 _libelf_elfmachine(e));
106 (*xlator)(phdr, phnum * msz, e->e_rawfile + phoff, phnum,
107 e->e_byteorder != LIBELF_PRIVATE(byteorder));
108
109 return (phdr);
110 }
111
112 void *
_libelf_newphdr(Elf * e,int ec,size_t count)113 _libelf_newphdr(Elf *e, int ec, size_t count)
114 {
115 void *ehdr, *newphdr, *oldphdr;
116 size_t msz;
117
118 if (e == NULL) {
119 LIBELF_SET_ERROR(ARGUMENT, 0);
120 return (NULL);
121 }
122
123 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) {
124 LIBELF_SET_ERROR(SEQUENCE, 0);
125 return (NULL);
126 }
127
128 assert(e->e_class == ec);
129 assert(ec == ELFCLASS32 || ec == ELFCLASS64);
130 assert(e->e_version == EV_CURRENT);
131
132 if ((msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version)) == 0)
133 return (NULL);
134
135 newphdr = NULL;
136 if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
137 LIBELF_SET_ERROR(RESOURCE, 0);
138 return (NULL);
139 }
140
141 if (ec == ELFCLASS32) {
142 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
143 free(oldphdr);
144 e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
145 } else {
146 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
147 free(oldphdr);
148 e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
149 }
150
151 e->e_u.e_elf.e_nphdr = count;
152
153 elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
154
155 return (newphdr);
156 }
157