fix: prevent null pointer dereference in privilege cleanup

[robertkill]

1. Added null check for m_session pointer before calling deleteLater()
2. This prevents potential crashes when m_session is null during privilege cleanup
3. The original code assumed m_session was always valid, which could lead to segmentation faults

Influence:

1. Test privilege escalation scenarios where authentication might fail
2. Verify cleanup doesn't crash when session ends unexpectedly
3. Test multiple privilege requests in sequence
4. Verify memory management during authentication cancellation

fix: 修复权限清理中的空指针解引用问题

1. 在调用 deleteLater() 前添加了对 m_session 指针的空值检查
2. 防止在权限清理过程中 m_session 为空时可能导致的崩溃
3. 原始代码假设 m_session 始终有效，这可能导致段错误

Influence:

1. 测试认证可能失败的特权提升场景
2. 验证会话意外结束时清理过程不会崩溃
3. 测试连续多次特权请求
4. 验证认证取消时的内存管理

PMS: BUG-344183

Summary by Sourcery

Bug Fixes:

• Prevent a potential crash by checking m_session for null before invoking deleteLater() during privilege cleanup.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Adds a null check around the PolicyKit session pointer before invoking deleteLater() during privilege cleanup to avoid crashes when the session is unexpectedly null.

Sequence diagram for privilege cleanup with null-safe session handling

sequenceDiagram
    actor User
    participant PolicyKitListener
    participant PolkitSession as m_session
    participant Dialog as m_dialog

    User->>PolicyKitListener: finishObtainPrivilege()
    PolicyKitListener->>PolicyKitListener: fillResult()

    alt m_session is not null
        PolicyKitListener->>PolkitSession: deleteLater()
    else m_session is null
        PolicyKitListener->>PolicyKitListener: skip deleteLater()
    end

    PolicyKitListener->>Dialog: close()
    PolicyKitListener->>PolicyKitListener: m_inProgress = false

Loading

Class diagram for PolicyKitListener privilege cleanup changes

classDiagram
    class PolicyKitListener {
        - QSharedPointer m_session
        - Dialog* m_dialog
        - bool m_inProgress
        + finishObtainPrivilege() void
        - fillResult() void
    }

    class QSharedPointer {
        + isNull() bool
        + data() QObject*
    }

    class Dialog {
        + close() void
    }

    class QObject {
        + deleteLater() void
    }

    PolicyKitListener --> QSharedPointer : owns m_session
    PolicyKitListener --> Dialog : uses
    QSharedPointer --> QObject : wraps
    Dialog --|> QObject

Loading

File-Level Changes

Change	Details	Files
Guard session cleanup against null pointer dereference in privilege completion path.	Wrap the m_session deleteLater() call in a null check using m_session.isNull() Ensure privilege cleanup continues safely even when no valid session exists, preventing potential segmentation faults	policykitlistener.cpp

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[sourcery-ai]

Hey there - I've reviewed your changes - here's some feedback:

• After calling deleteLater() on m_session.data(), consider also clearing the QPointer (e.g., m_session.clear()) to make it explicit that the pointer should no longer be used and to avoid accidental reuse elsewhere.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- After calling `deleteLater()` on `m_session.data()`, consider also clearing the `QPointer` (e.g., `m_session.clear()`) to make it explicit that the pointer should no longer be used and to avoid accidental reuse elsewhere.

## Individual Comments

### Comment 1
<location> `policykitlistener.cpp:143` </location>
<code_context>
     // to get cancel state, polkit-qt need be updated
     fillResult();
-    m_session.data()->deleteLater();
+    if (!m_session.isNull()) {
+        m_session.data()->deleteLater();
+    }
</code_context>

<issue_to_address>
**suggestion (bug_risk):** Consider resetting `m_session` after scheduling `deleteLater()` to avoid future misuse.

Given that we now guard `deleteLater()` with a null check, clearing `m_session` right after calling it (e.g. `m_session.clear()`) would make it explicit that the session must not be used again and reduce the risk of subtle use-after-free style issues elsewhere in the code.
</issue_to_address>

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[sourcery-ai]

suggestion (bug_risk): Consider resetting m_session after scheduling deleteLater() to avoid future misuse.

Given that we now guard deleteLater() with a null check, clearing m_session right after calling it (e.g. m_session.clear()) would make it explicit that the session must not be used again and reduce the risk of subtle use-after-free style issues elsewhere in the code.

[deepin-ci-robot]

deepin pr auto review

我来对这段代码进行审查：

1. 语法逻辑：
   修改后的代码在语法上是正确的。增加了对 m_session 的空指针检查，这是一个很好的改进。使用 isNull() 检查比直接判断指针是否为空更安全，因为这是 Qt 框架推荐的方式。

2. 代码质量：

• 修改后的代码质量更好，增加了防御性编程，避免了潜在的空指针解引用。
• 使用了 Qt 的智能指针(QSharedPointer)的 isNull() 方法进行检查，这是 Qt 框架的标准做法。

3. 代码性能：

• 性能影响很小。增加的空指针检查只是一个简单的条件判断，不会带来明显的性能开销。

4. 代码安全：

• 修改提高了代码的安全性，避免了可能的空指针解引用导致的程序崩溃。
• 使用 deleteLater() 而不是直接 delete 是一个很好的实践，这确保了对象会在适当的时候被安全删除，特别是在 Qt 的事件循环环境中。

改进建议：

1. 可以考虑在 m_session 被置空的地方也添加相应的注释，说明生命周期管理。
2. 考虑在 m_dialog->close() 之前也添加对 m_dialog 的空指针检查，保持一致的防御性编程风格。

总的来说，这是一个很好的改进，提高了代码的健壮性和安全性。建议采纳这个修改。

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: 18202781743, robertkill

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