hypnosec (2231454) writes "Matthew Garrett has published some patches today out of which few break hibernate and kexec support on Linux when secure boot is running. The reason behind disabling hibernate functionalities is that currently the Linux kernel doesn’t have the capability of verifying the resume image when returning from hibernation, which compromises the Secure Boot trust model. The reason for disabling the kexec support while running in Secure Boot is that the kernel execution mechanism may be used to attack the system by a malicious user such as disabling of swap, writing of a pre-formed resume image to swap, etc. Kexec can be used to load a modified kernel thus bypassing the trust model of Secure Boot."
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