IDT-Based Security Sandbox Call Gate Kernel Panic Prevention
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Solution Overview
Problem
IDT-based security sandboxes can cause kernel panics when using a call gate due to conflicts between the kernel and application handling of interrupts, particularly with timer interrupts, leading to potential stack overflow or incorrect assumptions about stack contents.
Innovation Solution
A method that enables a call gate by executing an interrupt disable instruction before jumping through it, ensuring the secure sandbox is set up with a lower privilege level, preventing kernel panics by managing stack transitions and interrupt handling effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a call gate is used to transition to driver-controlled code in an IDT-based sandbox, then the sandbox can operate with lower privilege levels and intercept interrupts, but the stack is switched to a high privilege stack which may cause kernel panics or stack overflow when interrupts occur
Solution Approach 1:
The patent applies preliminary action by disabling interrupts before transitioning through the call gate to driver-controlled code. This prevents any interrupt from occurring during the critical transition period when the stack is being switched from low privilege to high privilege stack, eliminating the risk of kernel panic or stack overflow that would occur if an interrupt were to fire during this vulnerable window
2Adaptability or versatility
If interrupts are not disabled before jumping through the call gate, then the system can respond to timer interrupts and other events, but the kernel may make incorrect assumptions about stack contents leading to panic or stack overflow
Solution Approach 1:
The patent applies preliminary anti-action by disabling interrupts before the call gate transition, which prevents the harmful effect of interrupt handlers making incorrect assumptions about stack contents. The interrupt disable instruction acts as a countermeasure that eliminates the possibility of timer interrupts or other events firing during the stack transition, thereby preventing kernel panic or stack overflow
Data Source
AI summary
A method and apparatus for preventing an IDT-based security sandbox from causing a kernel panic when using a call gate is disclosed. The method comprises receiving a request from an application to create a secure sandbox, wherein epilog code is mapped into the application upon receiving the request; enabling a call gate, wherein the call gate defines a location of call gate target code for enabling the secure sandbox; executing the epilog code to facilitate an interrupt disable instruction; jumping through the call gate; and enabling the secure sandbox.