libelf_phdr.c revision 367466 
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
34ELFTC_VCSID("$Id: libelf_phdr.c 3732 2019-04-22 11:08:38Z jkoshy $");
35
36void *
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
112void *
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