Google Online Security Blog: Protecting against code reuse in the Linux kernel with Shadow Call Stack

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Protecting against code reuse in the Linux kernel with Shadow Call Stack

30 ottobre 2019

Posted by Sami Tolvanen, Staff Software Engineer, Android Security & Privacy Team

Control-Flow Integrity (CFI)Shadow Call Stack (SCS) Return-oriented programmingReturn-oriented programming (ROP)automatically generating this type of kernel exploit Shadow Call Stack

4.144.19upstream LinuxCONFIG_SHADOW_CALL_STACK=y # CONFIG_SHADOW_CALL_STACK_VMAP is not set # CONFIG_DEBUG_STACK_USAGE is not set By default, shadow stacks are not virtually allocated to minimize memory overhead, but CONFIG_SHADOW_CALL_STACK_VMAP can be enabled for better stack exhaustion protection. With CONFIG_DEBUG_STACK_USAGE, the kernel will also print out shadow stack usage in addition to normal stack usage which can be helpful when debugging issues.
AlternativesARMv8.3 Pointer Authentication (PAC)Control-flow Enforcement Technology (CET) Conclusion