nodejs process.setgid、process.setuid 行為與 fs 模塊

Question

目錄：

drwxrwxr-x  2 alex alex 4096 Aug  3 12:03 ./
drwxr-xr-x 17 alex alex 4096 Aug  3 11:18 ../
-rwx------  1 root root   19 Aug  3 11:24 privilegedStuff*
-rwxrwx---  1 root root   28 Aug  3 12:10 privilegedStuff1*
-rwxrwxr-x  1 alex alex  830 Aug  3 12:12 test.js*

測試.js：

#!/usr/bin/env node
var fs = require('fs');
console.log('           user id: ', process.getuid());
console.log('          group id: ', process.getgid());
console.log(' user effective id: ', process.getegid());
console.log('group effective id: ', process.getegid());
console.log('\n switching user and group...\n');
process.setgid(1000);
process.setegid(1000);
process.setuid(1000);
process.seteuid(1000);
console.log('           user id: ', process.getuid());
console.log('          group id: ', process.getgid());
console.log(' user effective id: ', process.getegid());
console.log('group effective id: ', process.getegid());
console.log('\n output: \n');

console.log(fs.readFileSync('./privilegedStuff1', 'utf8'))

// this throws error as expected so I commented that
// console.log(fs.readFileSync('./privilegedStuff', 'utf8'))

特權材料1：

content of privilegedStuff1

結果：

alex@hp:/apps/test$ sudo ./test.js 
           user id:  0
          group id:  0
 user effective id:  0
group effective id:  0

 switching user and group...

           user id:  1000
          group id:  1000
 user effective id:  1000
group effective id:  1000

 output: 

content of privilegedStuff1

所以我不明白的是為什么 node 不會拋出錯誤，因為它很好地處理了 privilegedStuff 文件？ 我錯過了什么？

alex@hp:/apps/test$ groups
alex adm cdrom sudo dip plugdev lpadmin sambashare
alex@hp:/apps/test$ cat privilegedStuff1
cat: privilegedStuff1: Permission denied
alex@hp:/apps/test$ sudo -s
root@hp:/apps/test# groups
root

Answer 1

在我的測試中，我沒有這樣的問題。

您能否輸入以下命令並顯示結果：

ls -l privilegedStuff1
id