tree e28dcb2c683b62a463714c891187cb0cbe96a1e3
parent c2d616eaee4e562399403e5816246b657739a98e
author Gaurav Aggarwal <aggarg@amazon.com> 1662542857 +0530
committer Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com> 1663353188 +0530

Remove local stack variable form MPU wrappers

It was possible for a third party that had already independently gained
the ability to execute injected code to achieve further privilege
escalation by branching directly inside a FreeRTOS MPU API wrapper
function with a manually crafted stack frame. This commit removes the
local stack variable `xRunningPrivileged` so that a manually crafted
stack frame cannot be used for privilege escalation by branching
directly inside a FreeRTOS MPU API wrapper.

We thank Certibit Consulting, LLC, Huazhong University of Science and
Technology and the SecLab team at Northeastern University for reporting
this issue.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>