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,v 1.2 2019/03/19 02:31:35 jsg Exp $"); 35 36 void * 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 msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT); 91 92 assert(msz > 0); 93 94 if ((phdr = calloc(phnum, msz)) == NULL) { 95 LIBELF_SET_ERROR(RESOURCE, 0); 96 return (NULL); 97 } 98 99 if (ec == ELFCLASS32) 100 e->e_u.e_elf.e_phdr.e_phdr32 = phdr; 101 else 102 e->e_u.e_elf.e_phdr.e_phdr64 = phdr; 103 104 105 xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec, 106 _libelf_elfmachine(e)); 107 (*xlator)(phdr, phnum * msz, e->e_rawfile + phoff, phnum, 108 e->e_byteorder != LIBELF_PRIVATE(byteorder)); 109 110 return (phdr); 111 } 112 113 void * 114 _libelf_newphdr(Elf *e, int ec, size_t count) 115 { 116 void *ehdr, *newphdr, *oldphdr; 117 size_t msz; 118 119 if (e == NULL) { 120 LIBELF_SET_ERROR(ARGUMENT, 0); 121 return (NULL); 122 } 123 124 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) { 125 LIBELF_SET_ERROR(SEQUENCE, 0); 126 return (NULL); 127 } 128 129 assert(e->e_class == ec); 130 assert(ec == ELFCLASS32 || ec == ELFCLASS64); 131 assert(e->e_version == EV_CURRENT); 132 133 msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version); 134 135 assert(msz > 0); 136 137 newphdr = NULL; 138 if (count > 0 && (newphdr = calloc(count, msz)) == NULL) { 139 LIBELF_SET_ERROR(RESOURCE, 0); 140 return (NULL); 141 } 142 143 if (ec == ELFCLASS32) { 144 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL) 145 free(oldphdr); 146 e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr; 147 } else { 148 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL) 149 free(oldphdr); 150 e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr; 151 } 152 153 e->e_u.e_elf.e_nphdr = count; 154 155 elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY); 156 157 return (newphdr); 158 } 159