diff --git a/modules/admin.js b/modules/admin.js
index e9917c5..44f4dfc 100644
--- a/modules/admin.js
+++ b/modules/admin.js
@@ -304,7 +304,7 @@ app.post('/admin/other', async (req, res) => {
       const submissions = await JudgeState.find();
       for (const s of submissions) {
         if (s.type !== 'submit-answer') {
-          s.code_length = s.code.length;
+          s.code_length = Buffer.from(s.code).length;
           await s.save();
         }
       }
diff --git a/modules/contest.js b/modules/contest.js
index beee933..5d8786b 100644
--- a/modules/contest.js
+++ b/modules/contest.js
@@ -432,7 +432,7 @@ app.get('/contest/submission/:id', async (req, res) => {
     judge.problem.title = syzoj.utils.removeTitleTag(judge.problem.title);
 
     if (judge.problem.type !== 'submit-answer') {
-      judge.codeLength = judge.code.length;
+      judge.codeLength = Buffer.from(judge.code).length;
       judge.code = await syzoj.utils.highlight(judge.code, syzoj.languages[judge.language].highlight);
     }
 
diff --git a/modules/problem.js b/modules/problem.js
index 8b4e744..fd25b15 100644
--- a/modules/problem.js
+++ b/modules/problem.js
@@ -172,7 +172,7 @@ app.get('/problems/tag/:tagIDs', async (req, res) => {
       problem.allowedEdit = await problem.isAllowedEditBy(res.locals.user);
       problem.judge_state = await problem.getJudgeState(res.locals.user, true);
       problem.tags = await problem.getTags();
-      
+
       return problem;
     });
 
@@ -279,7 +279,7 @@ app.get('/problem/:id/edit', async (req, res) => {
       problem = await Problem.create({
         time_limit: syzoj.config.default.problem.time_limit,
         memory_limit: syzoj.config.default.problem.memory_limit,
-        type: 'traditional' 
+        type: 'traditional'
       });
       problem.id = id;
       problem.allowedEdit = true;
@@ -314,7 +314,7 @@ app.post('/problem/:id/edit', async (req, res) => {
       problem = await Problem.create({
         time_limit: syzoj.config.default.problem.time_limit,
         memory_limit: syzoj.config.default.problem.memory_limit,
-        type: 'traditional' 
+        type: 'traditional'
       });
 
       if (await res.locals.user.hasPrivilege('manage_problem')) {
@@ -381,7 +381,7 @@ app.get('/problem/:id/import', async (req, res) => {
       problem = await Problem.create({
         time_limit: syzoj.config.default.problem.time_limit,
         memory_limit: syzoj.config.default.problem.memory_limit,
-        type: 'traditional' 
+        type: 'traditional'
       });
       problem.id = id;
       problem.new = true;
@@ -415,7 +415,7 @@ app.post('/problem/:id/import', async (req, res) => {
       problem = await Problem.create({
         time_limit: syzoj.config.default.problem.time_limit,
         memory_limit: syzoj.config.default.problem.memory_limit,
-        type: 'traditional' 
+        type: 'traditional'
       });
 
       if (await res.locals.user.hasPrivilege('manage_problem')) {
@@ -646,7 +646,7 @@ app.post('/problem/:id/submit', app.multer.fields([{ name: 'answer', maxCount: 1
         if (req.files['answer'][0].size > syzoj.config.limit.submit_code) throw new ErrorMessage('代码文件太大。');
         code = (await fs.readFile(req.files['answer'][0].path)).toString();
       } else {
-        if (req.body.code.length > syzoj.config.limit.submit_code) throw new ErrorMessage('代码太长。');
+        if (Buffer.from(req.body.code).length > syzoj.config.limit.submit_code) throw new ErrorMessage('代码太长。');
         code = req.body.code;
       }
 
@@ -655,7 +655,7 @@ app.post('/problem/:id/submit', app.multer.fields([{ name: 'answer', maxCount: 1
         status: 'Unknown',
         task_id: randomstring.generate(10),
         code: code,
-        code_length: code.length,
+        code_length: Buffer.from(code).length,
         language: req.body.language,
         user_id: curUser.id,
         problem_id: req.params.id,
@@ -930,7 +930,7 @@ app.post('/problem/:id/custom-test', app.multer.fields([{ name: 'code_upload', m
       if (req.files['code_upload'][0].size > syzoj.config.limit.submit_code) throw new ErrorMessage('代码过长。');
       code = (await require('fs-extra').readFileAsync(req.files['code_upload'][0].path)).toString();
     } else {
-      if (req.body.code.length > syzoj.config.limit.submit_code) throw new ErrorMessage('代码过长。');
+      if (Buffer.from(req.body.code).length > syzoj.config.limit.submit_code) throw new ErrorMessage('代码过长。');
       code = req.body.code;
     }
 
diff --git a/modules/submission.js b/modules/submission.js
index 74c4a2b..af58da2 100644
--- a/modules/submission.js
+++ b/modules/submission.js
@@ -110,7 +110,7 @@ app.get('/submissions', async (req, res) => {
     const judge_state = queryResult.data;
     await judge_state.forEachAsync(async obj => {
       await obj.loadRelationships();
-      if (obj.problem.type !== 'submit-answer') obj.code_length = obj.code.length;
+      if (obj.problem.type !== 'submit-answer') obj.code_length = Buffer.from(obj.code).length;
     });
 
     res.render('submissions', {
@@ -160,7 +160,7 @@ app.get('/submission/:id', async (req, res) => {
     await judge.loadRelationships();
 
     if (judge.problem.type !== 'submit-answer') {
-      judge.code_length = judge.code.length;
+      judge.code_length = Buffer.from(judge.code).length;
 
       let key = syzoj.utils.getFormattedCodeKey(judge.code, judge.language);
       if (key) {