1 | /*- |
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2 | * Copyright (c) 2006,2008 Joseph Koshy |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * 1. Redistributions of source code must retain the above copyright |
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9 | * notice, this list of conditions and the following disclaimer. |
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10 | * 2. Redistributions in binary form must reproduce the above copyright |
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11 | * notice, this list of conditions and the following disclaimer in the |
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12 | * documentation and/or other materials provided with the distribution. |
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13 | * |
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14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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24 | * SUCH DAMAGE. |
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25 | */ |
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26 | |
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27 | #include <sys/cdefs.h> |
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28 | |
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29 | #include <assert.h> |
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30 | #include <libelf.h> |
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31 | |
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32 | #include "_libelf.h" |
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33 | |
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34 | LIBELF_VCSID("$Id$"); |
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35 | |
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36 | /* |
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37 | * Translate to/from the file representation of ELF objects. |
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38 | * |
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39 | * Translation could potentially involve the following |
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40 | * transformations: |
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41 | * |
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42 | * - an endianness conversion, |
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43 | * - a change of layout, as the file representation of ELF objects |
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44 | * can differ from their in-memory representation. |
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45 | * - a change in representation due to a layout version change. |
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46 | */ |
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47 | |
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48 | Elf_Data * |
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49 | _libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding, |
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50 | int elfclass, int direction) |
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51 | { |
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52 | int byteswap; |
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53 | size_t cnt, dsz, fsz, msz; |
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54 | uintptr_t sb, se, db, de; |
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55 | |
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56 | if (encoding == ELFDATANONE) |
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57 | encoding = LIBELF_PRIVATE(byteorder); |
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58 | |
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59 | if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) || |
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60 | dst == NULL || src == NULL || dst == src) { |
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61 | LIBELF_SET_ERROR(ARGUMENT, 0); |
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62 | return (NULL); |
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63 | } |
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64 | |
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65 | assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64); |
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66 | assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY); |
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67 | |
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68 | if (dst->d_version != src->d_version) { |
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69 | LIBELF_SET_ERROR(UNIMPL, 0); |
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70 | return (NULL); |
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71 | } |
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72 | |
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73 | if (src->d_buf == NULL || dst->d_buf == NULL) { |
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74 | LIBELF_SET_ERROR(DATA, 0); |
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75 | return (NULL); |
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76 | } |
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77 | |
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78 | if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) { |
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79 | LIBELF_SET_ERROR(DATA, 0); |
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80 | return (NULL); |
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81 | } |
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82 | |
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83 | if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize) |
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84 | (src->d_type, (size_t) 1, src->d_version)) == 0) |
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85 | return (NULL); |
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86 | |
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87 | msz = _libelf_msize(src->d_type, elfclass, src->d_version); |
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88 | |
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89 | assert(msz > 0); |
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90 | |
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91 | if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) { |
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92 | LIBELF_SET_ERROR(DATA, 0); |
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93 | return (NULL); |
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94 | } |
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95 | |
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96 | /* |
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97 | * Determine the number of objects that need to be converted, and |
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98 | * the space required for the converted objects in the destination |
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99 | * buffer. |
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100 | */ |
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101 | if (direction == ELF_TOMEMORY) { |
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102 | cnt = src->d_size / fsz; |
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103 | dsz = cnt * msz; |
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104 | } else { |
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105 | cnt = src->d_size / msz; |
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106 | dsz = cnt * fsz; |
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107 | } |
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108 | |
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109 | if (dst->d_size < dsz) { |
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110 | LIBELF_SET_ERROR(DATA, 0); |
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111 | return (NULL); |
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112 | } |
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113 | |
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114 | sb = (uintptr_t) src->d_buf; |
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115 | se = sb + src->d_size; |
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116 | db = (uintptr_t) dst->d_buf; |
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117 | de = db + dst->d_size; |
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118 | |
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119 | /* |
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120 | * Check for overlapping buffers. Note that db == sb is |
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121 | * allowed. |
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122 | */ |
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123 | if (db != sb && de > sb && se > db) { |
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124 | LIBELF_SET_ERROR(DATA, 0); |
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125 | return (NULL); |
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126 | } |
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127 | |
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128 | if ((direction == ELF_TOMEMORY ? db : sb) % |
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129 | _libelf_malign(src->d_type, elfclass)) { |
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130 | LIBELF_SET_ERROR(DATA, 0); |
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131 | return (NULL); |
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132 | } |
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133 | |
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134 | dst->d_type = src->d_type; |
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135 | dst->d_size = dsz; |
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136 | |
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137 | byteswap = encoding != LIBELF_PRIVATE(byteorder); |
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138 | |
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139 | if (src->d_size == 0 || |
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140 | (db == sb && !byteswap && fsz == msz)) |
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141 | return (dst); /* nothing more to do */ |
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142 | |
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143 | if (!(_libelf_get_translator(src->d_type, direction, elfclass)) |
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144 | (dst->d_buf, dsz, src->d_buf, cnt, byteswap)) { |
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145 | LIBELF_SET_ERROR(DATA, 0); |
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146 | return (NULL); |
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147 | } |
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148 | |
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149 | return (dst); |
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150 | } |
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