1 | #include <stdio.h> |
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2 | #include <stdlib.h> |
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3 | /* #include <unistd.h> */ |
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4 | /* #include <sys/mman.h> */ |
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5 | /* #include <errno.h> */ |
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6 | /* #include <string.h> */ |
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7 | |
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8 | #define SELF_CODE_MODIFYING 1 |
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9 | #define SELF_CODE_MODIFYING_ADDR 1 |
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10 | // 0 : with label in function |
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11 | // 1 : fixed |
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12 | |
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13 | |
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14 | #if SELF_CODE_MODIFYING |
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15 | static int self_code_modifying_nb_runs; |
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16 | extern char self_code_modifying_function_destination_start; |
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17 | extern char self_code_modifying_function_destination_end; |
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18 | extern char self_code_modifying_function_source_start; |
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19 | extern char self_code_modifying_function_source_end; |
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20 | |
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21 | int self_code_modifying_manage (int nb_runs); |
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22 | void self_code_modifying_function_source (void); |
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23 | void self_code_modifying_function_destination(void); |
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24 | |
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25 | int self_code_modifying(int nb_runs) |
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26 | { |
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27 | return self_code_modifying_manage(nb_runs); |
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28 | } |
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29 | |
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30 | int self_code_modifying_manage(int nb_runs) |
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31 | { |
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32 | |
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33 | // // Change the memory protection |
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34 | // unsigned page = (unsigned)&self_code_modifying_function_destination_start & ~( getpagesize() - 1 ); |
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35 | // |
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36 | // if( mprotect( (char*)page, getpagesize(), PROT_READ | PROT_WRITE | PROT_EXEC ) ) |
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37 | // { |
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38 | // perror( "mprotect failed" ); |
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39 | // exit( errno ); |
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40 | // } |
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41 | |
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42 | // First execution |
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43 | self_code_modifying_function_destination(); |
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44 | |
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45 | |
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46 | #if (SELF_CODE_MODIFYING_ADDR==0) |
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47 | int function_source_start = (int)&self_code_modifying_function_source_start ; |
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48 | int function_source_end = (int)&self_code_modifying_function_source_end ; |
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49 | int function_destination_start = (int)&self_code_modifying_function_destination_start; |
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50 | int function_destination_end = (int)&self_code_modifying_function_destination_end ; |
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51 | #elif (SELF_CODE_MODIFYING_ADDR==1) |
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52 | int function_source_start = 0x00400330; |
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53 | int function_source_end = 0x00400358; |
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54 | int function_destination_start = 0x0040036c; |
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55 | int function_destination_end = 0x004004d8; |
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56 | #else |
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57 | #error "Invalid SELF_CODE_MODIFYING_ADDR." |
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58 | #endif |
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59 | |
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60 | int size_source = function_source_end -function_source_start; |
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61 | int size_destination = function_destination_end-function_destination_start; |
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62 | |
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63 | printf(" * self_code_modifying_function_destination : %x to %x (%d bytes)\n",function_destination_start,function_destination_end,size_destination); |
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64 | printf(" * self_code_modifying_function_source : %x to %x (%d bytes)\n",function_source_start ,function_source_end ,size_source); |
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65 | |
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66 | if (size_destination<size_source) |
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67 | { |
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68 | printf("Size of destination is too short\n"); |
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69 | return 1; |
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70 | } |
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71 | |
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72 | printf(" * memcpy\n"); |
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73 | memcpy((void*)function_destination_start, (void*)function_source_start, function_source_end - function_source_start ); |
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74 | |
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75 | while (self_code_modifying_nb_runs<nb_runs) |
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76 | { |
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77 | self_code_modifying_function_destination(); |
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78 | } |
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79 | |
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80 | return 0; |
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81 | } |
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82 | |
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83 | void self_code_modifying_function_source(void) |
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84 | { |
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85 | int (*callPrintf )(const char *format, ...); |
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86 | |
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87 | asm volatile( "self_code_modifying_function_source_start:" ); |
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88 | |
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89 | (*(callPrintf=&printf))( " + self_code_modifying_function_source\n" ); |
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90 | self_code_modifying_nb_runs++; |
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91 | (*(callPrintf=&printf))( " + Number of call : %d\n",self_code_modifying_nb_runs); |
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92 | |
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93 | asm volatile( "self_code_modifying_function_source_end:"); |
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94 | } |
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95 | |
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96 | void self_code_modifying_function_destination(void) |
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97 | { |
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98 | int (*callPrintf )(const char *format, ...); |
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99 | |
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100 | asm volatile( "self_code_modifying_function_destination_start:"); |
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101 | |
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102 | (*(callPrintf=&printf))( " + self_code_modifying_function_destination\n" ); |
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103 | |
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104 | // Padding |
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105 | asm volatile (//".set push \n\t" |
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106 | //".set noreorder \n\t" |
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107 | //".set noat \n\t" |
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108 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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109 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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110 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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111 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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112 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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113 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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114 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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115 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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116 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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117 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t" |
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118 | "nop; nop; nop; nop; nop; nop; nop; nop;\n\t"); |
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119 | |
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120 | asm volatile( "self_code_modifying_function_destination_end:"); |
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121 | } |
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122 | |
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123 | #else |
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124 | |
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125 | int self_code_modifying(int nb_runs) |
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126 | { |
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127 | return 0; |
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128 | } |
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129 | |
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130 | #endif |
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