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 <libelf.h> 29 30 #include "_libelf.h" 31 32 ELFTC_VCSID("$Id: libelf_xlate.c 3174 2015-03-27 17:13:41Z emaste $"); 33 34 /* 35 * Translate to/from the file representation of ELF objects. 36 * 37 * Translation could potentially involve the following 38 * transformations: 39 * 40 * - an endianness conversion, 41 * - a change of layout, as the file representation of ELF objects 42 * can differ from their in-memory representation. 43 * - a change in representation due to a layout version change. 44 */ 45 46 Elf_Data * 47 _libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding, 48 int elfclass, int direction) 49 { 50 int byteswap; 51 size_t cnt, dsz, fsz, msz; 52 uintptr_t sb, se, db, de; 53 54 if (encoding == ELFDATANONE) 55 encoding = LIBELF_PRIVATE(byteorder); 56 57 if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) || 58 dst == NULL || src == NULL || dst == src) { 59 LIBELF_SET_ERROR(ARGUMENT, 0); 60 return (NULL); 61 } 62 63 assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64); 64 assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY); 65 66 if (dst->d_version != src->d_version) { 67 LIBELF_SET_ERROR(UNIMPL, 0); 68 return (NULL); 69 } 70 71 if (src->d_buf == NULL || dst->d_buf == NULL) { 72 LIBELF_SET_ERROR(DATA, 0); 73 return (NULL); 74 } 75 76 if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) { 77 LIBELF_SET_ERROR(DATA, 0); 78 return (NULL); 79 } 80 81 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize) 82 (src->d_type, (size_t) 1, src->d_version)) == 0) 83 return (NULL); 84 85 msz = _libelf_msize(src->d_type, elfclass, src->d_version); 86 87 assert(msz > 0); 88 89 if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) { 90 LIBELF_SET_ERROR(DATA, 0); 91 return (NULL); 92 } 93 94 /* 95 * Determine the number of objects that need to be converted, and 96 * the space required for the converted objects in the destination 97 * buffer. 98 */ 99 if (direction == ELF_TOMEMORY) { 100 cnt = (size_t) src->d_size / fsz; 101 dsz = cnt * msz; 102 } else { 103 cnt = (size_t) src->d_size / msz; 104 dsz = cnt * fsz; 105 } 106 107 if (dst->d_size < dsz) { 108 LIBELF_SET_ERROR(DATA, 0); 109 return (NULL); 110 } 111 112 sb = (uintptr_t) src->d_buf; 113 se = sb + (size_t) src->d_size; 114 db = (uintptr_t) dst->d_buf; 115 de = db + (size_t) dst->d_size; 116 117 /* 118 * Check for overlapping buffers. Note that db == sb is 119 * allowed. 120 */ 121 if (db != sb && de > sb && se > db) { 122 LIBELF_SET_ERROR(DATA, 0); 123 return (NULL); 124 } 125 126 if ((direction == ELF_TOMEMORY ? db : sb) % 127 _libelf_malign(src->d_type, elfclass)) { 128 LIBELF_SET_ERROR(DATA, 0); 129 return (NULL); 130 } 131 132 dst->d_type = src->d_type; 133 dst->d_size = dsz; 134 135 byteswap = encoding != LIBELF_PRIVATE(byteorder); 136 137 if (src->d_size == 0 || 138 (db == sb && !byteswap && fsz == msz)) 139 return (dst); /* nothing more to do */ 140 141 if (!(_libelf_get_translator(src->d_type, direction, elfclass)) 142 (dst->d_buf, dsz, src->d_buf, cnt, byteswap)) { 143 LIBELF_SET_ERROR(DATA, 0); 144 return (NULL); 145 } 146 147 return (dst); 148 } 149