1 /* $NetBSD: libelf_phdr.c,v 1.5 2024/03/03 17:37:34 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2006,2008 Joseph Koshy 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #if HAVE_NBTOOL_CONFIG_H 30 # include "nbtool_config.h" 31 #endif 32 33 #include <sys/cdefs.h> 34 35 #include <assert.h> 36 #include <gelf.h> 37 #include <libelf.h> 38 #include <stdlib.h> 39 40 #include "_libelf.h" 41 42 __RCSID("$NetBSD: libelf_phdr.c,v 1.5 2024/03/03 17:37:34 christos Exp $"); 43 ELFTC_VCSID("Id: libelf_phdr.c 3977 2022-05-01 06:45:34Z jkoshy"); 44 45 void * 46 _libelf_getphdr(Elf *e, int ec) 47 { 48 size_t phnum; 49 size_t fsz, msz; 50 uint64_t phoff; 51 Elf32_Ehdr *eh32; 52 Elf64_Ehdr *eh64; 53 void *ehdr, *phdr; 54 _libelf_translator_function *xlator; 55 56 assert(ec == ELFCLASS32 || ec == ELFCLASS64); 57 58 if (e == NULL) { 59 LIBELF_SET_ERROR(ARGUMENT, 0); 60 return (NULL); 61 } 62 63 if ((phdr = (ec == ELFCLASS32 ? 64 (void *) e->e_u.e_elf.e_phdr.e_phdr32 : 65 (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL) 66 return (phdr); 67 68 /* 69 * Check the PHDR related fields in the EHDR for sanity. 70 */ 71 72 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 73 return (NULL); 74 75 phnum = e->e_u.e_elf.e_nphdr; 76 77 if (ec == ELFCLASS32) { 78 eh32 = (Elf32_Ehdr *) ehdr; 79 phoff = (uint64_t) eh32->e_phoff; 80 } else { 81 eh64 = (Elf64_Ehdr *) ehdr; 82 phoff = (uint64_t) eh64->e_phoff; 83 } 84 85 fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version); 86 87 assert(fsz > 0); 88 89 if (phoff + fsz < phoff) { /* Numeric overflow. */ 90 LIBELF_SET_ERROR(HEADER, 0); 91 return (NULL); 92 } 93 94 if ((uint64_t) e->e_rawsize < (phoff + fsz)) { 95 LIBELF_SET_ERROR(HEADER, 0); 96 return (NULL); 97 } 98 99 if ((msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT)) == 0) 100 return (NULL); 101 102 if ((phdr = calloc(phnum, msz)) == NULL) { 103 LIBELF_SET_ERROR(RESOURCE, 0); 104 return (NULL); 105 } 106 107 if (ec == ELFCLASS32) 108 e->e_u.e_elf.e_phdr.e_phdr32 = phdr; 109 else 110 e->e_u.e_elf.e_phdr.e_phdr64 = phdr; 111 112 113 xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec, 114 _libelf_elfmachine(e)); 115 (*xlator)(phdr, phnum * msz, e->e_rawfile + phoff, phnum, 116 e->e_byteorder != LIBELF_PRIVATE(byteorder)); 117 118 return (phdr); 119 } 120 121 void * 122 _libelf_newphdr(Elf *e, int ec, size_t count) 123 { 124 void *ehdr, *newphdr, *oldphdr; 125 size_t msz; 126 127 if (e == NULL) { 128 LIBELF_SET_ERROR(ARGUMENT, 0); 129 return (NULL); 130 } 131 132 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) { 133 LIBELF_SET_ERROR(SEQUENCE, 0); 134 return (NULL); 135 } 136 137 assert(e->e_class == ec); 138 assert(ec == ELFCLASS32 || ec == ELFCLASS64); 139 assert(e->e_version == EV_CURRENT); 140 141 if ((msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version)) == 0) 142 return (NULL); 143 144 newphdr = NULL; 145 if (count > 0 && (newphdr = calloc(count, msz)) == NULL) { 146 LIBELF_SET_ERROR(RESOURCE, 0); 147 return (NULL); 148 } 149 150 if (ec == ELFCLASS32) { 151 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL) 152 free(oldphdr); 153 e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr; 154 } else { 155 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL) 156 free(oldphdr); 157 e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr; 158 } 159 160 e->e_u.e_elf.e_nphdr = count; 161 162 elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY); 163 164 return (newphdr); 165 } 166