长城杯及第五空间部分wp

本文最后更新于：2021年9月24日 晚上

Reverse

funny_js

Quickjs，参考https://blog.d2x3.cn/kctf2020-%E7%AC%AC%E4%B8%89%E9%A2%98-%E5%AF%BB%E8%B8%AA%E8%A7%85%E6%BA%90.html

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https://gitee.com/haloxxg/QuickJS/releases 下载对应版本
修改 quickjs.c，使其输出bytecode
make install 进行编译
echo "console.log('hello')" > ctf.js
./qjsc -o ctf ctf.js
./ctf

得到输出：

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0000:  02 04                    4 atom indexes {
0002:  0e 63 6f 6e 73 6f 6c 65    string: 1"console"
000a:  06 6c 6f 67                string: 1"log"
000e:  0a 68 65 6c 6c 6f          string: 1"hello"
0014:  0c 63 74 66 2e 6a 73       string: 1"ctf.js"
                                }
001b:  0e                       function {
001c:  00 06 00 9e 01 00 01 00
       03 00 00 14 01             name: "<eval>"
                                  args=0 vars=1 defargs=0 closures=0 cpool=0
                                  stack=3 bclen=20 locals=1
                                  vars {
0029:  a0 01 00 00 00               name: "<ret>"
                                  }
                                  bytecode {
002e:  39 df 00 00 00 43 e0 00
       00 00 04 e1 00 00 00 24
       01 00 cf 28                  at 1, fixup atom: console
                                    at 6, fixup atom: log
                                    at 11, fixup atom: hello
                                  }
                                  debug {
0042:  c4 03 01 00                  filename: "ctf.js"
                                  }
                                }
ctf.js:1: function: <eval>
  locals:
    0: var <ret>
  stack_size: 3
  opcodes:
        get_var console
        get_field2 log
        push_atom_value hello
        call_method 1
        set_loc0 0: "<ret>"
        return

hello

测试成功，然后去分析程序找opcode。

image-20210922150612577

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dump opcode，保存为c文件。

#include "quickjs-libc.h"

const uint32_t qjsc_ctf_size = 0x490;

const uint8_t qjsc_ctf[0x490] = {
    0x02, 0x1B, 0x06, 0x72, 0x63, 0x34, 0x04, 0x73, 0x6E, 0x02, 0x69, 0x02, 0x6A, 0x02, 0x6B, 0x02, 
    0x6C, 0x02, 0x6D, 0x02, 0x6E, 0x04, 0x75, 0x6E, 0x06, 0x61, 0x72, 0x72, 0x0C, 0x63, 0x69, 0x70, 
    0x68, 0x65, 0x72, 0x2A, 0x32, 0x30, 0x32, 0x31, 0x71, 0x75, 0x69, 0x63, 0x6B, 0x6A, 0x73, 0x5F, 
    0x68, 0x61, 0x70, 0x70, 0x79, 0x67, 0x61, 0x6D, 0x65, 0x48, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 
    0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 
    0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x2A, 0x02, 0x73, 
    0x18, 0x66, 0x72, 0x6F, 0x6D, 0x43, 0x68, 0x61, 0x72, 0x43, 0x6F, 0x64, 0x65, 0x0A, 0x70, 0x72, 
    0x69, 0x6E, 0x74, 0x12, 0x73, 0x6F, 0x75, 0x72, 0x63, 0x65, 0x2E, 0x6A, 0x73, 0x08, 0x64, 0x61, 
    0x74, 0x61, 0x06, 0x6B, 0x65, 0x79, 0x06, 0x62, 0x6F, 0x78, 0x02, 0x78, 0x08, 0x74, 0x65, 0x6D, 
    0x70, 0x02, 0x79, 0x06, 0x6F, 0x75, 0x74, 0x08, 0x63, 0x6F, 0x64, 0x65, 0x14, 0x63, 0x68, 0x61, 
    0x72, 0x43, 0x6F, 0x64, 0x65, 0x41, 0x74, 0x08, 0x70, 0x75, 0x73, 0x68, 0x0E, 0x00, 0x06, 0x00, 
    0x9E, 0x01, 0x00, 0x01, 0x00, 0x20, 0x00, 0x08, 0xEB, 0x04, 0x01, 0xA0, 0x01, 0x00, 0x00, 0x00, 
    0x40, 0xDF, 0x00, 0x00, 0x00, 0x40, 0x40, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x40, 0xE1, 0x00, 0x00, 
    0x00, 0x00, 0x40, 0xE2, 0x00, 0x00, 0x00, 0x00, 0x40, 0xE3, 0x00, 0x00, 0x00, 0x00, 0x40, 0xE4, 
    0x00, 0x00, 0x00, 0x00, 0x40, 0xE5, 0x00, 0x00, 0x00, 0x00, 0x40, 0xE6, 0x00, 0x00, 0x00, 0x00, 
    0x40, 0xE7, 0x00, 0x00, 0x00, 0x00, 0x40, 0xE8, 0x00, 0x00, 0x00, 0x00, 0x40, 0xE9, 0x00, 0x00, 
    0x00, 0x00, 0x40, 0xE1, 0x00, 0x00, 0x00, 0x00, 0xC2, 0x00, 0x41, 0xDF, 0x00, 0x00, 0x00, 0x00, 
    0x3F, 0xE0, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xE1, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xE2, 0x00, 0x00, 
    0x00, 0x00, 0x3F, 0xE3, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xE4, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xE5, 
    0x00, 0x00, 0x00, 0x00, 0x3F, 0xE6, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xE7, 0x00, 0x00, 0x00, 0x00, 
    0x3F, 0xE8, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xE9, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xE1, 0x00, 0x00, 
    0x00, 0x00, 0x04, 0xEA, 0x00, 0x00, 0x00, 0x11, 0x3A, 0xE7, 0x00, 0x00, 0x00, 0x0E, 0x04, 0xEB, 
    0x00, 0x00, 0x00, 0x11, 0x3A, 0xE0, 0x00, 0x00, 0x00, 0xCB, 0xC0, 0x96, 0x00, 0xC0, 0xE0, 0x00, 
    0xC0, 0xF4, 0x00, 0xBF, 0x44, 0xBF, 0x3D, 0xBF, 0x7D, 0xBF, 0x08, 0xC0, 0xEF, 0x00, 0xC0, 0xCB, 
    0x00, 0xC0, 0xFE, 0x00, 0xC0, 0xF1, 0x00, 0xBF, 0x71, 0xC0, 0xD5, 0x00, 0xC0, 0xB0, 0x00, 0xBF, 
    0x40, 0xBF, 0x6A, 0xBF, 0x67, 0xC0, 0xA6, 0x00, 0xC0, 0xB9, 0x00, 0xC0, 0x9F, 0x00, 0xC0, 0x9E, 
    0x00, 0xC0, 0xAC, 0x00, 0xBF, 0x09, 0xC0, 0xD5, 0x00, 0xC0, 0xEF, 0x00, 0xBF, 0x0C, 0xBF, 0x64, 
    0xC0, 0xB9, 0x00, 0xBF, 0x5A, 0xC0, 0xAE, 0x00, 0xBF, 0x6B, 0xC0, 0x83, 0x00, 0x26, 0x20, 0x00, 
    0xC0, 0xDF, 0x00, 0x4D, 0x20, 0x00, 0x00, 0x80, 0xBF, 0x7A, 0x4D, 0x21, 0x00, 0x00, 0x80, 0xC0, 
    0xE5, 0x00, 0x4D, 0x22, 0x00, 0x00, 0x80, 0xC0, 0x9D, 0x00, 0x4D, 0x23, 0x00, 0x00, 0x80, 0x11, 
    0x3A, 0xE8, 0x00, 0x00, 0x00, 0x0E, 0xC1, 0x01, 0x11, 0x3A, 0xE5, 0x00, 0x00, 0x00, 0xCB, 0xC1, 
    0x02, 0x11, 0x3A, 0xE6, 0x00, 0x00, 0x00, 0xCB, 0xB7, 0x11, 0x3A, 0xE4, 0x00, 0x00, 0x00, 0xCB, 
    0xB7, 0x11, 0x3A, 0xE3, 0x00, 0x00, 0x00, 0xCB, 0x39, 0xDF, 0x00, 0x00, 0x00, 0x39, 0xE0, 0x00, 
    0x00, 0x00, 0x39, 0xE7, 0x00, 0x00, 0x00, 0xF2, 0x11, 0x3A, 0xE9, 0x00, 0x00, 0x00, 0x0E, 0x06, 
    0xCB, 0xB7, 0x11, 0x3A, 0xE1, 0x00, 0x00, 0x00, 0x0E, 0x39, 0xE1, 0x00, 0x00, 0x00, 0x39, 0xE9, 
    0x00, 0x00, 0x00, 0xEB, 0xA5, 0xEC, 0x6E, 0x39, 0xE9, 0x00, 0x00, 0x00, 0x39, 0xE1, 0x00, 0x00, 
    0x00, 0x48, 0x11, 0x3A, 0xE2, 0x00, 0x00, 0x00, 0xCB, 0x39, 0xE2, 0x00, 0x00, 0x00, 0xBF, 0x38, 
    0xBF, 0x11, 0xA0, 0xB0, 0x11, 0x3A, 0xE4, 0x00, 0x00, 0x00, 0xCB, 0x06, 0xCB, 0x39, 0xE4, 0x00, 
    0x00, 0x00, 0x39, 0xE8, 0x00, 0x00, 0x00, 0x39, 0xE3, 0x00, 0x00, 0x00, 0x48, 0xAB, 0xEC, 0x0F, 
    0x39, 0xE5, 0x00, 0x00, 0x00, 0x93, 0x3A, 0xE5, 0x00, 0x00, 0x00, 0xCB, 0xEE, 0x0D, 0x39, 0xE6, 
    0x00, 0x00, 0x00, 0x93, 0x3A, 0xE6, 0x00, 0x00, 0x00, 0xCB, 0x39, 0xE3, 0x00, 0x00, 0x00, 0x93, 
    0x3A, 0xE3, 0x00, 0x00, 0x00, 0xCB, 0x39, 0xE1, 0x00, 0x00, 0x00, 0x93, 0x3A, 0xE1, 0x00, 0x00, 
    0x00, 0x0E, 0xEE, 0x86, 0x06, 0xCB, 0x39, 0xE5, 0x00, 0x00, 0x00, 0x39, 0xE9, 0x00, 0x00, 0x00, 
    0xEB, 0xAB, 0xEC, 0x15, 0x39, 0xE6, 0x00, 0x00, 0x00, 0xB7, 0xAB, 0xEC, 0x0C, 0xC1, 0x03, 0x11, 
    0x3A, 0xE6, 0x00, 0x00, 0x00, 0xCB, 0xEE, 0x0A, 0xC1, 0x04, 0x11, 0x3A, 0xE6, 0x00, 0x00, 0x00, 
    0xCB, 0xC3, 0x11, 0x3A, 0xEC, 0x00, 0x00, 0x00, 0xCB, 0x06, 0xCB, 0x39, 0xE6, 0x00, 0x00, 0x00, 
    0xC1, 0x05, 0xA7, 0xEC, 0x3A, 0x39, 0xEC, 0x00, 0x00, 0x00, 0x39, 0x97, 0x00, 0x00, 0x00, 0x43, 
    0xED, 0x00, 0x00, 0x00, 0x39, 0x96, 0x00, 0x00, 0x00, 0x39, 0xE6, 0x00, 0x00, 0x00, 0xC1, 0x06, 
    0x9E, 0xF1, 0x24, 0x01, 0x00, 0x9F, 0x11, 0x3A, 0xEC, 0x00, 0x00, 0x00, 0xCB, 0x39, 0xE6, 0x00, 
    0x00, 0x00, 0xC1, 0x07, 0x9D, 0x11, 0x3A, 0xE6, 0x00, 0x00, 0x00, 0xCB, 0xEE, 0xBE, 0x39, 0xEE, 
    0x00, 0x00, 0x00, 0x39, 0xEC, 0x00, 0x00, 0x00, 0xF1, 0xCF, 0x28, 0xDE, 0x03, 0x01, 0x20, 0x00, 
    0x48, 0x01, 0x00, 0x4A, 0x52, 0x3F, 0x40, 0x00, 0x7C, 0x04, 0x30, 0x30, 0x2B, 0x2B, 0x77, 0x7B, 
    0x5D, 0x5D, 0x6C, 0x3F, 0x0E, 0x40, 0x3F, 0x4A, 0xB7, 0x30, 0x2B, 0x3F, 0xCB, 0x4E, 0x0D, 0x0E, 
    0x43, 0x06, 0x00, 0xBE, 0x03, 0x02, 0x08, 0x02, 0x05, 0x00, 0x00, 0xBB, 0x01, 0x0A, 0xE0, 0x03, 
    0x00, 0x01, 0x00, 0xE2, 0x03, 0x00, 0x01, 0x00, 0xE4, 0x03, 0x00, 0x00, 0x00, 0xC2, 0x03, 0x00, 
    0x01, 0x00, 0xE6, 0x03, 0x00, 0x02, 0x00, 0xE8, 0x03, 0x00, 0x03, 0x00, 0xEA, 0x03, 0x00, 0x04, 
    0x00, 0xEC, 0x03, 0x00, 0x05, 0x00, 0xEE, 0x03, 0x00, 0x06, 0x00, 0xC6, 0x03, 0x00, 0x07, 0x00, 
    0x39, 0x94, 0x00, 0x00, 0x00, 0xC0, 0x00, 0x01, 0xF1, 0xCB, 0xB7, 0xCC, 0xC8, 0xC0, 0x00, 0x01, 
    0xA5, 0xEC, 0x09, 0xC7, 0xC8, 0xC8, 0x4A, 0x95, 0x01, 0xEE, 0xF2, 0xB7, 0xCD, 0xB7, 0xCC, 0xC8, 
    0xC0, 0x00, 0x01, 0xA5, 0xEC, 0x2C, 0xC9, 0xC7, 0xC8, 0x48, 0x9F, 0xD4, 0x43, 0xF8, 0x00, 0x00, 
    0x00, 0xC8, 0xD4, 0xEB, 0x9E, 0x24, 0x01, 0x00, 0x9F, 0xC0, 0x00, 0x01, 0x9E, 0xCD, 0xC7, 0xC8, 
    0x48, 0xCE, 0xC7, 0xC8, 0x72, 0xC7, 0xC9, 0x48, 0x4A, 0xC7, 0xC9, 0xCA, 0x4A, 0x95, 0x01, 0xEE, 
    0xCF, 0xB7, 0xCD, 0xB7, 0xC5, 0x04, 0x26, 0x00, 0x00, 0xC5, 0x05, 0xB7, 0xCC, 0xC8, 0xD3, 0xEB, 
    0xA5, 0xEC, 0x56, 0xD3, 0x43, 0xF8, 0x00, 0x00, 0x00, 0xC8, 0x24, 0x01, 0x00, 0xC5, 0x06, 0xC9, 
    0xB8, 0x9F, 0xC0, 0x00, 0x01, 0x9E, 0xCD, 0xC4, 0x04, 0xC7, 0xC9, 0x48, 0x9F, 0xC0, 0x00, 0x01, 
    0x9E, 0xC5, 0x04, 0xC7, 0xC9, 0x48, 0xCE, 0xC7, 0xC9, 0x72, 0xC7, 0xC4, 0x04, 0x48, 0x4A, 0xC7, 
    0xC4, 0x04, 0xCA, 0x4A, 0xC7, 0xC9, 0x48, 0xC7, 0xC4, 0x04, 0x48, 0x9F, 0xC0, 0x00, 0x01, 0x9E, 
    0xC5, 0x07, 0xC4, 0x05, 0x43, 0xF9, 0x00, 0x00, 0x00, 0xC4, 0x06, 0xC7, 0xC4, 0x07, 0x48, 0xB0, 
    0x24, 0x01, 0x00, 0x0E, 0x95, 0x01, 0xEE, 0xA6, 0xC4, 0x05, 0x28, 0xDE, 0x03, 0x03, 0x19, 0x04, 
    0x35, 0x30, 0x17, 0x18, 0x0D, 0x30, 0x7B, 0x17, 0x26, 0x17, 0x19, 0x0D, 0x12, 0x1C, 0x2C, 0x40, 
    0x2B, 0x3F, 0x17, 0x2B, 0x1D, 0x4A, 0x5D, 0x17, 0x0A, 0x00, 0x0A, 0x00, 0x0A, 0xE8, 0x01, 0x07, 
    0x44, 0xB8, 0x90, 0xB5, 0x6B, 0x67, 0x80, 0x0A, 0xE8, 0x01, 0x07, 0x34, 0xA7, 0xB8, 0x48, 0x7F, 
    0x8D, 0xAF, 0x0A, 0x00, 0x0A, 0x28, 0x01, 0xFE, 0x0A, 0x28, 0x01, 0xFE, 0x00, 0x00, 0x00, 0x00
};

int main(int argc, char **argv)
{
  JSRuntime *rt;
  JSContext *ctx;
  rt = JS_NewRuntime();
  ctx = JS_NewContextRaw(rt);
  JS_SetModuleLoaderFunc(rt, NULL, js_module_loader, NULL);
  JS_AddIntrinsicBaseObjects(ctx);
  JS_AddIntrinsicDate(ctx);
  JS_AddIntrinsicEval(ctx);
  JS_AddIntrinsicStringNormalize(ctx);
  JS_AddIntrinsicRegExp(ctx);
  JS_AddIntrinsicJSON(ctx);
  JS_AddIntrinsicProxy(ctx);
  JS_AddIntrinsicMapSet(ctx);
  JS_AddIntrinsicTypedArrays(ctx);
  JS_AddIntrinsicPromise(ctx);
  JS_AddIntrinsicBigInt(ctx);
  js_std_add_helpers(ctx, argc, argv);
  js_std_eval_binary(ctx, qjsc_ctf, qjsc_ctf_size, 0);
  js_std_loop(ctx);
  JS_FreeContext(ctx);
  JS_FreeRuntime(rt);
  return 0;
}

然后编译
gcc funnyjs.c libquickjs.a -lm -ldl -o funnyjs

得到bytecode：

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522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
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629
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638
0000:  02 1b                    27 atom indexes {
0002:  06 72 63 34                string: 1"rc4"
0006:  04 73 6e                   string: 1"sn"
0009:  02 69                      string: 1"i"
000b:  02 6a                      string: 1"j"
000d:  02 6b                      string: 1"k"
000f:  02 6c                      string: 1"l"
0011:  02 6d                      string: 1"m"
0013:  02 6e                      string: 1"n"
0015:  04 75 6e                   string: 1"un"
0018:  06 61 72 72                string: 1"arr"
001c:  0c 63 69 70 68 65 72       string: 1"cipher"
0023:  2a 32 30 32 31 71 75 69
       63 6b 6a 73 5f 68 61 70
       70 79 67 61 6d 65          string: 1"2021quickjs_happygame"
0039:  48 2a 2a 2a 2a 2a 2a 2a
       2a 2a 2a 2a 2a 2a 2a 2a
       2a 2a 2a 2a 2a 2a 2a 2a
       2a 2a 2a 2a 2a 2a 2a 2a
       2a 2a 2a 2a 2a             string: 1"************************************"
005e:  02 73                      string: 1"s"
0060:  18 66 72 6f 6d 43 68 61
       72 43 6f 64 65             string: 1"fromCharCode"
006d:  0a 70 72 69 6e 74          string: 1"print"
0073:  12 73 6f 75 72 63 65 2e
       6a 73                      string: 1"source.js"
007d:  08 64 61 74 61             string: 1"data"
0082:  06 6b 65 79                string: 1"key"
0086:  06 62 6f 78                string: 1"box"
008a:  02 78                      string: 1"x"
008c:  08 74 65 6d 70             string: 1"temp"
0091:  02 79                      string: 1"y"
0093:  06 6f 75 74                string: 1"out"
0097:  08 63 6f 64 65             string: 1"code"
009c:  14 63 68 61 72 43 6f 64
       65 41 74                   string: 1"charCodeAt"
00a7:  08 70 75 73 68             string: 1"push"
                                }
00ac:  0e                       function {
00ad:  00 06 00 9e 01 00 01 00
       20 00 08 eb 04 01          name: "<eval>"
                                  args=0 vars=1 defargs=0 closures=0 cpool=8
                                  stack=32 bclen=619 locals=1
                                  vars {
00bb:  a0 01 00 00 00               name: "<ret>"
                                  }
                                  bytecode {
00c0:  40 df 00 00 00 40 40 e0
       00 00 00 00 40 e1 00 00
       00 00 40 e2 00 00 00 00
       40 e3 00 00 00 00 40 e4
       00 00 00 00 40 e5 00 00
       00 00 40 e6 00 00 00 00
       40 e7 00 00 00 00 40 e8
       00 00 00 00 40 e9 00 00
       00 00 40 e1 00 00 00 00
       c2 00 41 df 00 00 00 00
       3f e0 00 00 00 00 3f e1
       00 00 00 00 3f e2 00 00
       00 00 3f e3 00 00 00 00
       3f e4 00 00 00 00 3f e5
       00 00 00 00 3f e6 00 00
       00 00 3f e7 00 00 00 00
       3f e8 00 00 00 00 3f e9
       00 00 00 00 3f e1 00 00
       00 00 04 ea 00 00 00 11
       3a e7 00 00 00 0e 04 eb
       00 00 00 11 3a e0 00 00
       00 cb c0 96 00 c0 e0 00
       c0 f4 00 bf 44 bf 3d bf
       7d bf 08 c0 ef 00 c0 cb
       00 c0 fe 00 c0 f1 00 bf
       71 c0 d5 00 c0 b0 00 bf
       40 bf 6a bf 67 c0 a6 00
       c0 b9 00 c0 9f 00 c0 9e
       00 c0 ac 00 bf 09 c0 d5
       00 c0 ef 00 bf 0c bf 64
       c0 b9 00 bf 5a c0 ae 00
       bf 6b c0 83 00 26 20 00
       c0 df 00 4d 20 00 00 80
       bf 7a 4d 21 00 00 80 c0
       e5 00 4d 22 00 00 80 c0
       9d 00 4d 23 00 00 80 11
       3a e8 00 00 00 0e c1 01
       11 3a e5 00 00 00 cb c1
       02 11 3a e6 00 00 00 cb
       b7 11 3a e4 00 00 00 cb
       b7 11 3a e3 00 00 00 cb
       39 df 00 00 00 39 e0 00
       00 00 39 e7 00 00 00 f2
       11 3a e9 00 00 00 0e 06
       cb b7 11 3a e1 00 00 00
       0e 39 e1 00 00 00 39 e9
       00 00 00 eb a5 ec 6e 39
       e9 00 00 00 39 e1 00 00
       00 48 11 3a e2 00 00 00
       cb 39 e2 00 00 00 bf 38
       bf 11 a0 b0 11 3a e4 00
       00 00 cb 06 cb 39 e4 00
       00 00 39 e8 00 00 00 39
       e3 00 00 00 48 ab ec 0f
       39 e5 00 00 00 93 3a e5
       00 00 00 cb ee 0d 39 e6
       00 00 00 93 3a e6 00 00
       00 cb 39 e3 00 00 00 93
       3a e3 00 00 00 cb 39 e1
       00 00 00 93 3a e1 00 00
       00 0e ee 86 06 cb 39 e5
       00 00 00 39 e9 00 00 00
       eb ab ec 15 39 e6 00 00
       00 b7 ab ec 0c c1 03 11
       3a e6 00 00 00 cb ee 0a
       c1 04 11 3a e6 00 00 00
       cb c3 11 3a ec 00 00 00
       cb 06 cb 39 e6 00 00 00
       c1 05 a7 ec 3a 39 ec 00
       00 00 39 97 00 00 00 43
       ed 00 00 00 39 96 00 00
       00 39 e6 00 00 00 c1 06
       9e f1 24 01 00 9f 11 3a
       ec 00 00 00 cb 39 e6 00
       00 00 c1 07 9d 11 3a e6
       00 00 00 cb ee be 39 ee
       00 00 00 39 ec 00 00 00
       f1 cf 28                     at 1, fixup atom: rc4
                                    at 7, fixup atom: sn
                                    at 13, fixup atom: i
                                    at 19, fixup atom: j
                                    at 25, fixup atom: k
                                    at 31, fixup atom: l
                                    at 37, fixup atom: m
                                    at 43, fixup atom: n
                                    at 49, fixup atom: un
                                    at 55, fixup atom: arr
                                    at 61, fixup atom: cipher
                                    at 67, fixup atom: i
                                    at 75, fixup atom: rc4
                                    at 81, fixup atom: sn
                                    at 87, fixup atom: i
                                    at 93, fixup atom: j
                                    at 99, fixup atom: k
                                    at 105, fixup atom: l
                                    at 111, fixup atom: m
                                    at 117, fixup atom: n
                                    at 123, fixup atom: un
                                    at 129, fixup atom: arr
                                    at 135, fixup atom: cipher
                                    at 141, fixup atom: i
                                    at 147, fixup atom: "2021quickjs_happygame"
                                    at 153, fixup atom: un
                                    at 159, fixup atom: "************************************"
                                    at 165, fixup atom: sn
                                    at 260, fixup atom: "32"
                                    at 267, fixup atom: "33"
                                    at 275, fixup atom: "34"
                                    at 283, fixup atom: "35"
                                    at 289, fixup atom: arr
                                    at 298, fixup atom: m
                                    at 307, fixup atom: n
                                    at 315, fixup atom: l
                                    at 323, fixup atom: k
                                    at 329, fixup atom: rc4
                                    at 334, fixup atom: sn
                                    at 339, fixup atom: un
                                    at 346, fixup atom: cipher
                                    at 356, fixup atom: i
                                    at 362, fixup atom: i
                                    at 367, fixup atom: cipher
                                    at 376, fixup atom: cipher
                                    at 381, fixup atom: i
                                    at 388, fixup atom: j
                                    at 394, fixup atom: j
                                    at 406, fixup atom: l
                                    at 414, fixup atom: l
                                    at 419, fixup atom: arr
                                    at 424, fixup atom: k
                                    at 433, fixup atom: m
                                    at 439, fixup atom: m
                                    at 447, fixup atom: n
                                    at 453, fixup atom: n
                                    at 459, fixup atom: k
                                    at 465, fixup atom: k
                                    at 471, fixup atom: i
                                    at 477, fixup atom: i
                                    at 487, fixup atom: m
                                    at 492, fixup atom: cipher
                                    at 501, fixup atom: n
                                    at 513, fixup atom: n
                                    at 524, fixup atom: n
                                    at 532, fixup atom: s
                                    at 540, fixup atom: n
                                    at 550, fixup atom: s
                                    at 555, fixup atom: String
                                    at 560, fixup atom: fromCharCode
                                    at 565, fixup atom: Number
                                    at 570, fixup atom: n
                                    at 584, fixup atom: s
                                    at 590, fixup atom: n
                                    at 599, fixup atom: n
                                    at 607, fixup atom: print
                                    at 612, fixup atom: s
                                  }
                                  debug {
032b:  de 03 01 20 00 48 01 00
       4a 52 3f 40 00 7c 04 30
       30 2b 2b 77 7b 5d 5d 6c
       3f 0e 40 3f 4a b7 30 2b
       3f cb 4e 0d                  filename: "source.js"
                                  }
                                  cpool {
034f:  0e                           function {
0350:  43 06 00 be 03 02 08 02
       05 00 00 bb 01 0a              name: rc4
                                      args=2 vars=8 defargs=2 closures=0 cpool=0
                                      stack=5 bclen=187 locals=10
                                      vars {
035e:  e0 03 00 01 00                   name: data
0363:  e2 03 00 01 00                   name: key
0368:  e4 03 00 00 00                   name: box
036d:  c2 03 00 01 00                   name: i
0372:  e6 03 00 02 00                   name: x
0377:  e8 03 00 03 00                   name: temp
037c:  ea 03 00 04 00                   name: y
0381:  ec 03 00 05 00                   name: out
0386:  ee 03 00 06 00                   name: code
038b:  c6 03 00 07 00                   name: k
                                      }
                                      bytecode {
0390:  39 94 00 00 00 c0 00 01
       f1 cb b7 cc c8 c0 00 01
       a5 ec 09 c7 c8 c8 4a 95
       01 ee f2 b7 cd b7 cc c8
       c0 00 01 a5 ec 2c c9 c7
       c8 48 9f d4 43 f8 00 00
       00 c8 d4 eb 9e 24 01 00
       9f c0 00 01 9e cd c7 c8
       48 ce c7 c8 72 c7 c9 48
       4a c7 c9 ca 4a 95 01 ee
       cf b7 cd b7 c5 04 26 00
       00 c5 05 b7 cc c8 d3 eb
       a5 ec 56 d3 43 f8 00 00
       00 c8 24 01 00 c5 06 c9
       b8 9f c0 00 01 9e cd c4
       04 c7 c9 48 9f c0 00 01
       9e c5 04 c7 c9 48 ce c7
       c9 72 c7 c4 04 48 4a c7
       c4 04 ca 4a c7 c9 48 c7
       c4 04 48 9f c0 00 01 9e
       c5 07 c4 05 43 f9 00 00
       00 c4 06 c7 c4 07 48 b0
       24 01 00 0e 95 01 ee a6
       c4 05 28                         at 1, fixup atom: Array
                                        at 45, fixup atom: charCodeAt
                                        at 101, fixup atom: charCodeAt
                                        at 165, fixup atom: push
                                      }
                                      debug {
044b:  de 03 03 19 04 35 30 17
       18 0d 30 7b 17 26 17 19
       0d 12 1c 2c 40 2b 3f 17
       2b 1d 4a 5d 17                   filename: "source.js"
                                      }
                                    }
source.js:3: function: rc4
  args: data key
  locals:
    0: var box
    1: var i
    2: var x
    3: var temp
    4: var y
    5: var out
    6: var code
    7: var k
  stack_size: 5
  opcodes:
        get_var Array
        push_i16 256
        call1 1
        put_loc0 0: box
        push_0 0
        put_loc1 1: i
   12:  get_loc1 1: i
        push_i16 256
        lt
        if_false8 27
        get_loc0 0: box
        get_loc1 1: i
        get_loc1 1: i
        put_array_el
        inc_loc 1: i
        goto8 12
   27:  push_0 0
        put_loc2 2: x
        push_0 0
        put_loc1 1: i
   31:  get_loc1 1: i
        push_i16 256
        lt
        if_false8 81
        get_loc2 2: x
        get_loc0 0: box
        get_loc1 1: i
        get_array_el
        add
        get_arg1 1: key
        get_field2 charCodeAt
        get_loc1 1: i
        get_arg1 1: key
        get_length
        mod
        call_method 1
        add
        push_i16 256
        mod
        put_loc2 2: x
        get_loc0 0: box
        get_loc1 1: i
        get_array_el
        put_loc3 3: temp
        get_loc0 0: box
        get_loc1 1: i
        to_propkey2
        get_loc0 0: box
        get_loc2 2: x
        get_array_el
        put_array_el
        get_loc0 0: box
        get_loc2 2: x
        get_loc3 3: temp
        put_array_el
        inc_loc 1: i
        goto8 31
   81:  push_0 0
        put_loc2 2: x
        push_0 0
        put_loc8 4: y
        array_from 0
        put_loc8 5: out
        push_0 0
        put_loc1 1: i
   93:  get_loc1 1: i
        get_arg0 0: data
        get_length
        lt
        if_false8 184
        get_arg0 0: data
        get_field2 charCodeAt
        get_loc1 1: i
        call_method 1
        put_loc8 6: code
        get_loc2 2: x
        push_1 1
        add
        push_i16 256
        mod
        put_loc2 2: x
        get_loc8 4: y
        get_loc0 0: box
        get_loc2 2: x
        get_array_el
        add
        push_i16 256
        mod
        put_loc8 4: y
        get_loc0 0: box
        get_loc2 2: x
        get_array_el
        put_loc3 3: temp
        get_loc0 0: box
        get_loc2 2: x
        to_propkey2
        get_loc0 0: box
        get_loc8 4: y
        get_array_el
        put_array_el
        get_loc0 0: box
        get_loc8 4: y
        get_loc3 3: temp
        put_array_el
        get_loc0 0: box
        get_loc2 2: x
        get_array_el
        get_loc0 0: box
        get_loc8 4: y
        get_array_el
        add
        push_i16 256
        mod
        put_loc8 7: k
        get_loc8 5: out
        get_field2 push
        get_loc8 6: code
        get_loc0 0: box
        get_loc8 7: k
        get_array_el
        xor
        call_method 1
        drop
        inc_loc 1: i
        goto8 93
  184:  get_loc8 5: out
        return

0468:  0a                           bigint {
0469:  00                           }
046a:  0a                           bigint {
046b:  00                           }
046c:  0a                           bigint {
046d:  e8 01 07                       len=7
0470:  44 b8 90 b5 6b 67 80         }
0477:  0a                           bigint {
0478:  e8 01 07                       len=7
047b:  34 a7 b8 48 7f 8d af         }
0482:  0a                           bigint {
0483:  00                           }
0484:  0a                           bigint {
0485:  28 01                          len=1
0487:  fe                           }
0488:  0a                           bigint {
0489:  28 01                          len=1
048b:  fe                           }
                                  }
                                }
source.js:1: function: <eval>
  locals:
    0: var <ret>
  stack_size: 32
  opcodes:
        check_define_var rc4,64
        check_define_var sn,0
        check_define_var i,0
        check_define_var j,0
        check_define_var k,0
        check_define_var l,0
        check_define_var m,0
        check_define_var n,0
        check_define_var un,0
        check_define_var arr,0
        check_define_var cipher,0
        check_define_var i,0
        fclosure8 0: [bytecode rc4]
        define_func rc4,0
        define_var sn,0
        define_var i,0
        define_var j,0
        define_var k,0
        define_var l,0
        define_var m,0
        define_var n,0
        define_var un,0
        define_var arr,0
        define_var cipher,0
        define_var i,0
        push_atom_value "2021quickjs_happygame"
        dup
        put_var un
        drop
        push_atom_value "************************************"
        dup
        put_var sn
        put_loc0 0: "<ret>"
        push_i16 150
        push_i16 224
        push_i16 244
        push_i8 68
        push_i8 61
        push_i8 125
        push_i8 8
        push_i16 239
        push_i16 203
        push_i16 254
        push_i16 241
        push_i8 113
        push_i16 213
        push_i16 176
        push_i8 64
        push_i8 106
        push_i8 103
        push_i16 166
        push_i16 185
        push_i16 159
        push_i16 158
        push_i16 172
        push_i8 9
        push_i16 213
        push_i16 239
        push_i8 12
        push_i8 100
        push_i16 185
        push_i8 90
        push_i16 174
        push_i8 107
        push_i16 131
        array_from 32
        push_i16 223
        define_field "32"
        push_i8 122
        define_field "33"
        push_i16 229
        define_field "34"
        push_i16 157
        define_field "35"
        dup
        put_var arr
        drop
        push_const8 1: 0n
        dup
        put_var m
        put_loc0 0: "<ret>"
        push_const8 2: 0n
        dup
        put_var n
        put_loc0 0: "<ret>"
        push_0 0
        dup
        put_var l
        put_loc0 0: "<ret>"
        push_0 0
        dup
        put_var k
        put_loc0 0: "<ret>"
        get_var rc4
        get_var sn
        get_var un
        call2 2
        dup
        put_var cipher
        drop
        undefined
        put_loc0 0: "<ret>"
        push_0 0
        dup
        put_var i
        drop
  361:  get_var i
        get_var cipher
        get_length
        lt
        if_false8 484
        get_var cipher
        get_var i
        get_array_el
        dup
        put_var j
        put_loc0 0: "<ret>"
        get_var j
        push_i8 56
        push_i8 17
        sub
        xor
        dup
        put_var l
        put_loc0 0: "<ret>"
        undefined
        put_loc0 0: "<ret>"
        get_var l
        get_var arr
        get_var k
        get_array_el
        eq
        if_false8 446
        get_var m
        post_inc
        put_var m
        put_loc0 0: "<ret>"
        goto8 458
  446:  get_var n
        post_inc
        put_var n
        put_loc0 0: "<ret>"
  458:  get_var k
        post_inc
        put_var k
        put_loc0 0: "<ret>"
        get_var i
        post_inc
        put_var i
        drop
        goto8 361
  484:  undefined
        put_loc0 0: "<ret>"
        get_var m
        get_var cipher
        get_length
        eq
        if_false8 520
        get_var n
        push_0 0
        eq
        if_false8 520
        push_const8 3: 18071254662143010n
        dup
        put_var n
        put_loc0 0: "<ret>"
        goto8 529
  520:  push_const8 4: 24706849372394394n
        dup
        put_var n
        put_loc0 0: "<ret>"
  529:  push_empty_string
        dup
        put_var s
        put_loc0 0: "<ret>"
        undefined
        put_loc0 0: "<ret>"
  539:  get_var n
        push_const8 5: 0n
        gt
        if_false8 606
        get_var s
        get_var String
        get_field2 fromCharCode
        get_var Number
        get_var n
        push_const8 6: 127n
        mod
        call1 1
        call_method 1
        add
        dup
        put_var s
        put_loc0 0: "<ret>"
        get_var n
        push_const8 7: 127n
        div
        dup
        put_var n
        put_loc0 0: "<ret>"
        goto8 539
  606:  get_var print
        get_var s
        call1 1
        set_loc0 0: "<ret>"
        return

Error...

分析bytecode：

image-20210922151847572

给un,sn赋值。

image-20210922151921989

给arr赋值，

image-20210922152017170

调用了rc4加密函数，结果存入cipher。

image-20210922152151648

cipher与56-17求异或，然后与arr进行比较，至此，解题思路就很明显了。

先与39异或，然后再进行rc4解密。

image-20210922152641657

魔鬼凯撒的RC4茶室

第一部分改过的凯撒，第二部分rc4，但也不完全是，还算了半天key，浪费时间，它只和一个字符进行了异或，直接爆破。

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33
import string
import ctypes
s = "z8layn_b91_nb9ha1}kx"
str_upper = string.ascii_uppercase
str_num = string.digits
str_str = string.printable

res1 = ""
for j in range(len(s)):
    for i in str_str:
        ss = ord(i)
        a = 0
        if chr(ss) in str_upper:
            a = (ss + 32 + 20 - 97) % 26 + 97
        # if chr(ss) in str_lower:
        #     a = (i +  20 - 97) % 26 + 97
        if chr(ss) in str_num:
            a = (ss + 8 - 48) % 10 + 48
        if a == ord(s[j]):
            res1 += i
print(res1.lower())

key1 = hex(ctypes.c_uint32(-513026812).value)
key2 = hex(2028399278)
print(key1, key2)

tmp = [0x0D, 0x0A, 0xB2, 0xBF, 0xB9, 0xA5, 0xA6, 0xEF, 0xBF, 0xB1, 0xB3, 0xEF, 0xB0, 0xB9, 0x81, 0xEF, 0xAD, 0x81, 0xED, 0xB1, 0x81, 0xBB, 0xBF, 0xAD, 0xA7, 0x81]
for i in range(256):
    result = ""
    for j in range(len(tmp)):
        result += chr(tmp[j] ^ i)
    print(result)
#flag{x1aom1ng_1s_3o_easy_f0rget_h13_th1ng3}

第五空间uniapp

assert下找到app-service.js进行分析，使用pycharm进行格式化，发现了chacha20加密。

复制加密函数，调用decrypt进行解密：

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var r = function (t, e, n) {
            if ("undefined" === typeof n && (n = 0), !(t instanceof Uint8Array) || 32 !== t.length) throw new Error("Key should be 32 byte array!");
            if (!(e instanceof Uint8Array) || 12 !== e.length) throw new Error("Nonce should be 12 byte array!");
            this._rounds = 20, this._sigma = [1634760805, 857760878, 2036477234, 1797285236], this._param = [this._sigma[0], this._sigma[1], this._sigma[2], this._sigma[3], this._get32(t, 0), this._get32(t, 4), this._get32(t, 8), this._get32(t, 12), this._get32(t, 16), this._get32(t, 20), this._get32(t, 24), this._get32(t, 28), n, this._get32(e, 0), this._get32(e, 4), this._get32(e, 8)], this._keystream = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], this._byteCounter = 0
        };
        r.prototype._chacha = function () {
            var t = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], e = 0, n = 0;
            for (e = 0; e < 16; e++) t[e] = this._param[e];
            for (e = 0; e < this._rounds; e += 2) this._quarterround(t, 0, 4, 8, 12), this._quarterround(t, 1, 5, 9, 13), this._quarterround(t, 2, 6, 10, 14), this._quarterround(t, 3, 7, 11, 15), this._quarterround(t, 0, 5, 10, 15), this._quarterround(t, 1, 6, 11, 12), this._quarterround(t, 2, 7, 8, 13), this._quarterround(t, 3, 4, 9, 14);
            for (e = 0; e < 16; e++) t[e] += this._param[e], this._keystream[n++] = 255 & t[e], this._keystream[n++] = t[e] >>> 8 & 255, this._keystream[n++] = t[e] >>> 16 & 255, this._keystream[n++] = t[e] >>> 24 & 255
        }, r.prototype._quarterround = function (t, e, n, r, o) {
            t[o] = this._rotl(t[o] ^ (t[e] += t[n]), 16), t[n] = this._rotl(t[n] ^ (t[r] += t[o]), 12), t[o] = this._rotl(t[o] ^ (t[e] += t[n]), 8), t[n] = this._rotl(t[n] ^ (t[r] += t[o]), 7), t[e] >>>= 0, t[n] >>>= 0, t[r] >>>= 0, t[o] >>>= 0
        }, r.prototype._get32 = function (t, e) {
            return t[e++] ^ t[e++] << 8 ^ t[e++] << 16 ^ t[e] << 24
        }, r.prototype._rotl = function (t, e) {
            return t << e | t >>> 32 - e
        }, r.prototype.encrypt = function (t) {
            return this._update(t)
        }, r.prototype.decrypt = function (t) {
            return this._update(t)
        }, r.prototype._update = function (t) {
            if (!(t instanceof Uint8Array) || 0 === t.length) throw new Error("Data should be type of bytes (Uint8Array) and not empty!");
            for (var e = new Uint8Array(t.length), n = 0; n < t.length; n++) 0 !== this._byteCounter && 64 !== this._byteCounter || (this._chacha(), this._param[12]++, this._byteCounter = 0), e[n] = t[n] ^ this._keystream[this._byteCounter++];
            return e
        };

p = [34, 69, 86, 242, 93, 72, 134, 226, 42, 138, 112, 56, 189, 53, 77, 178, 223, 76, 78, 221, 63, 40, 86, 231,121, 29, 154, 189, 204, 243, 205, 44, 141, 100, 13, 164, 35, 123]
i = new Uint8Array([0, 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])
a = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 74, 0, 0, 0, 0])
s = 1
f= new r(i,a,s)
c = new Uint8Array(p)
console.log(f.decrypt(c));


然后进行异或：

1
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3
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5
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7
8
9
10
Uint8Array = [
   0, 10,  7,  1, 29, 83, 95,  3,  5, 84,
  87, 87,  5, 86, 80, 95, 83, 95, 81, 95,
   2,  4, 80,  5,  7, 82, 80, 81, 82,  0,
   2, 84,  7, 95,  7,  7, 81, 27
]
flag = ""
for i in range(len(Uint8Array)):
    flag += chr(Uint8Array[i] ^ 102)
print(flag)
CTF赛题writeup
writeup

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