[Autofix][high] Alert #46: File created without restricting permissions

[xengine-qyt]

🤖 Copilot Autofix 自动修复报告

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📋 基本信息

字段	内容
Alert ID	#46
安全级别	high
规则名称	File created without restricting permissions
问题文件	XEngine_Module/XEngine_AIApi/AIApi_Help/AIApi_Help.cpp 第 208 行
CWE 分类	external/cwe/cwe-732
规则标签	external/cwe/cwe-732, security

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🔍 问题说明

File created without restricting permissions

When you create a file, take care to give it the most restrictive permissions possible. A typical mistake is to create the file with world-writable permissions. This can allow an attacker to write to the file, which can give them unexpected control over the program.

Recommendation

Files should usually be created with write permissions only for the current user. If broader permissions are needed, including the users' group should be sufficient. It is very rare that a file needs to be world-writable, and care should be taken not to make assumptions about the contents of any such file.

On Unix systems, it is possible for the user who runs the program to restrict file creation permissions using umask. However, a program should not assume t

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🤖 AI 修复思路

Use a file-creation API that allows explicitly setting restrictive permissions at creation time, instead of plain _xtfopen("wb").

Best fix in this snippet: replace _xtfopen with a secure POSIX-style open(..., O_WRONLY|O_CREAT|O_TRUNC, 0600) (owner read/write only), then convert to FILE* via _fdopen/fdopen for existing fwrite logic. This preserves current behavior (overwrite/create binary file and write decoded bytes) while enforcing restrictive permissions for newly created files.

Change location:

• File: XEngine_Module/XEngine_AIApi/AIApi_Help/AIApi_Help.cpp
• Region: around current lines 208–216 in AIApi_Help_Base64DecodecFile (the block that opens/writes/closes file)

Needed elements:

• No new third-party dependencies.
• Use existing CRT/POSIX functions (open, fdopen/_fdopen, close) and permission bits (S_IRUSR | S_IWUSR).

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✅ Review 检查清单

• 理解了漏洞的成因和影响范围
• 确认 AI 修复逻辑正确，没有遗漏边界情况
• 确认修复没有改变原有业务逻辑
• 确认没有引入新的安全问题
• CI / 单元测试全部通过
• 如有必要，已补充对应的测试用例

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