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fix(leet): Remove symbols from LeetDictionary (#43)
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* fix(leet): Remove symbols from LeetDictionary

* Use dictionary initializer and minor enhancement

* Dispose SHA256 eagerly

* wip: add more items to charmap

* wip: update placeholder

Co-authored-by: Steve <[email protected]>
Co-authored-by: GZTime <[email protected]>
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@Konano @hez2010 @GZTimeWalker
3 people authored Sep 23, 2022
1 parent 0d3c6c7 commit 63d86fc
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Showing 4 changed files with 50 additions and 20 deletions.
2 changes: 1 addition & 1 deletion GZCTF/CTFServer.csproj
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@
<ItemGroup>
<PackageReference Include="AspNetCoreRateLimit" Version="4.0.2" />
<PackageReference Include="Docker.DotNet" Version="3.125.12" />
<PackageReference Include="KubernetesClient" Version="8.0.68" />
<PackageReference Include="KubernetesClient" Version="9.0.25" />
<PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="6.0.9" />
<PackageReference Include="Microsoft.AspNetCore.SignalR.Protocols.Json" Version="6.0.9" />
<PackageReference Include="Microsoft.AspNetCore.SpaProxy" Version="6.0.9" />
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33 changes: 32 additions & 1 deletion GZCTF/ClientApp/src/components/ChallengeDetailModal.tsx
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Expand Up @@ -28,6 +28,7 @@ import { useTypographyStyles } from '@Utils/useTypographyStyles'
import api, { AnswerResult, ChallengeType } from '@Api'
import { ChallengeTagItemProps } from '../utils/ChallengeItem'
import MarkdownRender from './MarkdownRender'
import { useRef } from 'react'

interface ChallengeDetailModalProps extends ModalProps {
gameId: number
Expand Down Expand Up @@ -60,6 +61,30 @@ const Countdown: FC<{ time: string }> = ({ time }) => {
)
}

const FlagPlaceholders: string[] = [
'横看成岭侧成峰，flag 高低各不同',
'flag 当关，万夫莫开',
'寻寻觅觅，冷冷清清，flag 惨惨戚戚',
'问君能有几多愁？恰似一江 flag 向东流',
'人生得意须尽欢，莫使 flag 空对月',
'汉皇重色思 flag，御宇多年求不得',
'flag 几时有？把酒问青天',
'羽扇纶巾，谈笑间，flag 灰飞烟灭',
'浊酒一杯家万里，flag 未勒归无计',
'孤帆远影碧空尽，唯见 flag 天际流',
'安得 flag 千万间，大庇天下 ctfer 俱欢颜！',
'两个黄鹂鸣翠柳，一行 flag 上青天',
'flag 一场大梦，人生几度秋凉？',
'剪不断，理还乱，是 flag',
'蓦然回首，flag 却在，灯火阑珊处',
'稻花香里说丰年，听取 flag 一片',
'采菊东篱下，悠然见 flag',
'不畏 flag 遮望眼，自缘身在最高层',
'便纵有千种 flag，更与何人说？',
'人生自古谁无死？留取 flag 照汗青',
'借问 flag 何处有？牧童遥指杏花村'
]

const ChallengeDetailModal: FC<ChallengeDetailModalProps> = (props) => {
const { gameId, challengeId, tagData, title, score, solved, ...modalProps } = props
const [downloadOpened, { close: downloadClose, open: downloadOpen }] = useDisclosure(false)
Expand Down Expand Up @@ -234,6 +259,12 @@ const ChallengeDetailModal: FC<ChallengeDetailModalProps> = (props) => {
}
}

const placeholder = useRef('')

if (props.opened) {
placeholder.current = FlagPlaceholders[Math.floor(Math.random() * FlagPlaceholders.length)]
}

return (
<Modal
{...modalProps}
Expand Down Expand Up @@ -372,7 +403,7 @@ const ChallengeDetailModal: FC<ChallengeDetailModalProps> = (props) => {
) : (
<form onSubmit={onSubmit}>
<TextInput
placeholder="flag{...}"
placeholder={placeholder.current}
value={flag}
onChange={setFlag}
styles={{
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7 changes: 4 additions & 3 deletions GZCTF/Repositories/FileRepository.cs
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Expand Up @@ -30,8 +30,9 @@ public async Task<LocalFile> CreateOrUpdateFile(IFormFile file, string? fileName
await file.CopyToAsync(tmp, token);

tmp.Position = 0;
var hash = await SHA256.Create().ComputeHashAsync(tmp, token);
var fileHash = BitConverter.ToString(hash).Replace("-", "").ToLower();
using SHA256 sha256 = SHA256.Create();
var hash = await sha256.ComputeHashAsync(tmp, token); // TODO: change to use SHA256.HashDataAsync in .NET 7
var fileHash = BitConverter.ToString(hash).Replace("-", "").ToLowerInvariant();

var localFile = await GetFileByHash(fileHash, token);

Expand Down Expand Up @@ -110,4 +111,4 @@ public async Task<TaskStatus> DeleteFileByHash(string fileHash, CancellationToke

public Task<List<LocalFile>> GetFiles(int count, int skip, CancellationToken token = default)
=> context.Files.OrderBy(e => e.Name).Skip(skip).Take(count).ToListAsync(token);
}
}
28 changes: 13 additions & 15 deletions GZCTF/Utils/Codec.cs
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Expand Up @@ -79,12 +79,12 @@ public static class Leet
{
private readonly static Dictionary<char, string> CharMap = new()
{
{ 'A', "Aa4@" }, { 'B', "Bb68" }, { 'C', "Cc" }, { 'D', "Dd" }, { 'E', "Ee3" }, { 'F', "Ff1" },
{ 'G', "Gg69" }, { 'H', "Hh" }, { 'I', "Ii1l!" }, { 'J', "Jj" }, { 'K', "Kk" }, { 'L', "Ll1I" },
{ 'M', "Mm" }, { 'N', "Nn" }, { 'O', "Oo0" }, { 'P', "Pp" }, { 'Q', "Qq9" }, { 'R', "Rr" },
{ 'S', "Ss5$" }, { 'T', "Tt7" }, { 'U', "Uu" }, { 'V', "Vv" }, { 'W', "Ww" }, { 'X', "Xx" },
{ 'Y', "Yy" }, { 'Z', "Zz2" }, { '0', "0oO" }, { '1', "1!lI" }, { '2', "2zZ" }, { '3', "3eE" },
{ '4', "4aA" }, { '5', "5Ss" }, { '6', "6G" }, { '9', "9g" }
['A'] = "Aa4", ['B'] = "Bb68", ['C'] = "Cc", ['D'] = "Dd", ['E'] = "Ee3", ['F'] = "Ff1",
['G'] = "Gg69", ['H'] = "Hh", ['I'] = "Ii1l", ['J'] = "Jj", ['K'] = "Kk", ['L'] = "Ll1I",
['M'] = "Mm", ['N'] = "Nn", ['O'] = "Oo0", ['P'] = "Pp", ['Q'] = "Qq9", ['R'] = "Rr",
['S'] = "Ss5", ['T'] = "Tt7", ['U'] = "Uu", ['V'] = "Vv", ['W'] = "Ww", ['X'] = "Xx",
['Y'] = "Yy", ['Z'] = "Zz2", ['0'] = "0oO", ['1'] = "1lI", ['2'] = "2zZ", ['3'] = "3eE",
['4'] = "4aA", ['5'] = "5Ss", ['6'] = "6Gb", ['7'] = "7T", ['8'] = "8bB", ['9'] = "9g"
};

public static double LeetEntropy(string flag)
Expand Down Expand Up @@ -118,7 +118,7 @@ public static string LeetFlag(string original)
doLeet = false;
else if (doLeet && CharMap.TryGetValue(char.ToUpperInvariant(c), out string? table) && table is not null)
{
var nc = table.ElementAt(random.Next(table.Length));
var nc = table[random.Next(table.Length)];
sb.Append(nc);
continue;
}
Expand Down Expand Up @@ -160,7 +160,7 @@ public static string RandomPassword(int length)
public static string BytesToHex(byte[] bytes, bool useLower = true)
{
string output = BitConverter.ToString(bytes).Replace("-", "");
return useLower ? output.ToLower() : output.ToUpper();
return useLower ? output.ToLowerInvariant() : output.ToUpperInvariant();
}

/// <summary>
Expand Down Expand Up @@ -222,8 +222,7 @@ public static string Reverse(string s)
/// <returns></returns>
public static string StrMD5(string str, bool useBase64 = false)
{
MD5 md5 = MD5.Create();
byte[] output = md5.ComputeHash(Encoding.Default.GetBytes(str));
byte[] output = MD5.HashData(Encoding.Default.GetBytes(str));
if (useBase64)
return Convert.ToBase64String(output);
else
Expand All @@ -238,8 +237,7 @@ public static string StrMD5(string str, bool useBase64 = false)
/// <returns></returns>
public static string StrSHA256(string str, bool useBase64 = false)
{
SHA256 sha256 = SHA256.Create();
byte[] output = sha256.ComputeHash(Encoding.Default.GetBytes(str));
byte[] output = SHA256.HashData(Encoding.Default.GetBytes(str));
if (useBase64)
return Convert.ToBase64String(output);
else
Expand All @@ -252,13 +250,13 @@ public static string StrSHA256(string str, bool useBase64 = false)
/// <param name="str">原始字符串</param>
/// <returns></returns>
public static byte[] BytesMD5(string str)
=> MD5.Create().ComputeHash(Encoding.Default.GetBytes(str));
=> MD5.HashData(Encoding.Default.GetBytes(str));

/// <summary>
/// 获取SHA256哈希字节摘要
/// </summary>
/// <param name="str">原始字符串</param>
/// <returns></returns>
public static byte[] BytesSHA256(string str)
=> SHA256.Create().ComputeHash(Encoding.Default.GetBytes(str));
}
=> SHA256.HashData(Encoding.Default.GetBytes(str));
}

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