decode.c 7.14 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93
/*
 * Copyright 2012 Jacek Caban for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include "jscript.h"

#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(jscript);

/*
 * This file implements algorithm for decoding scripts encoded by
 * screnc.exe. The 'secret' algorithm that's well documented here:
 * http://www.virtualconspiracy.com/content/articles/breaking-screnc
 */

static const unsigned char pick_encoding[64] = {
    1,2,0,1,2,0,2,0,0,2,0,2,1,0,2,0,
    1,0,2,0,1,1,2,0,0,2,1,0,2,0,0,2,
    1,1,0,2,0,2,0,1,0,1,1,2,0,1,0,2,
    1,0,2,0,1,1,2,0,0,1,1,2,0,1,0,2};

static const unsigned char dictionary[][3] = {
    {0x00,0x00,0x00}, {0x01,0x01,0x01}, {0x02,0x02,0x02}, {0x03,0x03,0x03},
    {0x04,0x04,0x04}, {0x05,0x05,0x05}, {0x06,0x06,0x06}, {0x07,0x07,0x07},
    {0x08,0x08,0x08}, {0x7b,0x57,0x6e}, {0x0a,0x0a,0x0a}, {0x0b,0x0b,0x0b},
    {0x0c,0x0c,0x0c}, {0x0d,0x0d,0x0d}, {0x0e,0x0e,0x0e}, {0x0f,0x0f,0x0f},
    {0x10,0x10,0x10}, {0x11,0x11,0x11}, {0x12,0x12,0x12}, {0x13,0x13,0x13},
    {0x14,0x14,0x14}, {0x15,0x15,0x15}, {0x16,0x16,0x16}, {0x17,0x17,0x17},
    {0x18,0x18,0x18}, {0x19,0x19,0x19}, {0x1a,0x1a,0x1a}, {0x1b,0x1b,0x1b},
    {0x1c,0x1c,0x1c}, {0x1d,0x1d,0x1d}, {0x1e,0x1e,0x1e}, {0x1f,0x1f,0x1f},
    {0x32,0x2e,0x2d}, {0x30,0x47,0x75}, {0x21,0x7a,0x52}, {0x29,0x56,0x60},
    {0x5b,0x42,0x71}, {0x38,0x6a,0x5e}, {0x33,0x2f,0x49}, {0x3d,0x26,0x5c},
    {0x58,0x49,0x62}, {0x3a,0x41,0x7d}, {0x35,0x34,0x29}, {0x65,0x32,0x36},
    {0x39,0x5b,0x20}, {0x5c,0x76,0x7c}, {0x56,0x72,0x7a}, {0x73,0x43,0x7f},
    {0x66,0x38,0x6b}, {0x4e,0x39,0x63}, {0x45,0x70,0x33}, {0x6b,0x45,0x2b},
    {0x62,0x68,0x68}, {0x59,0x71,0x51}, {0x78,0x4f,0x66}, {0x5e,0x09,0x76},
    {0x7d,0x62,0x31}, {0x4a,0x44,0x64}, {0x6d,0x23,0x54}, {0x71,0x75,0x43},
    {0x00,0x00,0x00}, {0x60,0x7e,0x3a}, {0x00,0x00,0x00}, {0x53,0x5e,0x7e},
    {0x00,0x00,0x00}, {0x42,0x77,0x45}, {0x27,0x4a,0x2c}, {0x48,0x61,0x2a},
    {0x72,0x5d,0x74}, {0x75,0x22,0x27}, {0x31,0x4b,0x37}, {0x37,0x6f,0x44},
    {0x4d,0x4e,0x79}, {0x52,0x3b,0x59}, {0x22,0x4c,0x2f}, {0x54,0x50,0x6f},
    {0x6a,0x67,0x26}, {0x47,0x2a,0x72}, {0x64,0x7d,0x6a}, {0x2d,0x74,0x39},
    {0x20,0x54,0x7b}, {0x7f,0x2b,0x3f}, {0x2e,0x2d,0x38}, {0x4c,0x2c,0x77},
    {0x5d,0x30,0x67}, {0x7e,0x6e,0x53}, {0x6c,0x6b,0x47}, {0x6f,0x66,0x34},
    {0x79,0x35,0x78}, {0x74,0x25,0x5d}, {0x43,0x21,0x30}, {0x26,0x64,0x23},
    {0x76,0x4d,0x5a}, {0x25,0x52,0x5b}, {0x24,0x63,0x6c}, {0x2b,0x3f,0x48},
    {0x28,0x7b,0x55}, {0x23,0x78,0x70}, {0x41,0x29,0x69}, {0x34,0x28,0x2e},
    {0x09,0x73,0x4c}, {0x2a,0x59,0x21}, {0x44,0x33,0x24}, {0x3f,0x7f,0x4e},
    {0x77,0x6d,0x50}, {0x3b,0x55,0x09}, {0x55,0x53,0x56}, {0x69,0x7c,0x73},
    {0x61,0x3a,0x35}, {0x63,0x5f,0x61}, {0x50,0x65,0x4b}, {0x67,0x46,0x58},
    {0x51,0x58,0x3b}, {0x49,0x31,0x57}, {0x4f,0x69,0x22}, {0x46,0x6c,0x6d},
    {0x68,0x5a,0x4d}, {0x7c,0x48,0x25}, {0x36,0x27,0x28}, {0x70,0x5c,0x46},
    {0x6e,0x3d,0x4a}, {0x7a,0x24,0x32}, {0x2f,0x79,0x41}, {0x5f,0x37,0x3d},
    {0x4b,0x60,0x5f}, {0x5a,0x51,0x4f}, {0x2c,0x20,0x42}, {0x57,0x36,0x65}};

static const int digits[] = {
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
    0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
    0x3c, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
    0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
    0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
    0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
    0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
    0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
    0x31, 0x32, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff};

static BOOL decode_dword(const WCHAR *p, DWORD *ret)
{
    DWORD i;

    for(i=0; i<6; i++) {
94
        if(p[i] >= sizeof(digits)/sizeof(*digits) || digits[p[i]] == 0xff)
95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180
            return FALSE;
    }
    if(p[6] != '=' || p[7] != '=')
        return FALSE;

    *ret = (digits[p[0]] << 2)
        + (digits[p[1]] >> 4)
        + ((digits[p[1]] & 0xf) << 12)
        + ((digits[p[2]] >> 2) << 8)
        + ((digits[p[2]] & 0x3) << 22)
        + (digits[p[3]] << 16)
        + ((digits[p[4]] << 2) << 24)
        + ((digits[p[5]] >> 4) << 24);
    return TRUE;
}

HRESULT decode_source(WCHAR *code)
{
    const WCHAR *src = code;
    WCHAR *dst = code;

    static const WCHAR decode_beginW[] = {'#','@','~','^'};
    static const WCHAR decode_endW[] = {'^','#','~','@'};

    while(*src) {
        if(!strncmpW(src, decode_beginW, sizeof(decode_beginW)/sizeof(*decode_beginW))) {
            DWORD len, i, j=0, csum, s=0;

            src += sizeof(decode_beginW)/sizeof(*decode_beginW);

            if(!decode_dword(src, &len))
                return JS_E_INVALID_CHAR;

            src += 8;

            for(i=0; i<len; i++) {
                if (src[i] == '@') {
                    switch(src[++i]) {
                    case '#':
                        s += dst[j++] = '\r';
                        break;
                    case '&':
                        s += dst[j++] = '\n';
                        break;
                    case '!':
                        s += dst[j++] = '<';
                        break;
                    case '*':
                        s += dst[j++] = '>';
                        break;
                    case '$':
                        s += dst[j++] = '@';
                        break;
                    default:
                        FIXME("unescape %c\n", src[i]);
                        return E_FAIL;
                    }
                }else if (src[i] < 128) {
                    s += dst[j] = dictionary[src[i]][pick_encoding[j%64]];
                    j++;
                }else {
                    FIXME("Unsupported char %c\n", src[i]);
                    return E_FAIL;
                }
            }

            src += len;
            dst += j;

            if(!decode_dword(src, &csum) || s != csum)
                return JS_E_INVALID_CHAR;
            src += 8;

            if(strncmpW(src, decode_endW, sizeof(decode_endW)/sizeof(*decode_endW)))
                return JS_E_INVALID_CHAR;
            src += sizeof(decode_endW)/sizeof(*decode_endW);
        }else {
            *dst++ = *src++;
        }
    }

    *dst = 0;

    TRACE("decoded %s\n", debugstr_w(code));
    return S_OK;
}