Re: [PATCH v26 3/9] x86/cet/ibt: Handle signals for Indirect Branch Tracking
From: Kees Cook <hidden>
Date: 2021-04-28 20:31:14
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On Tue, Apr 27, 2021 at 01:47:14PM -0700, Yu-cheng Yu wrote:
When an indirect CALL/JMP instruction is executed and before it reaches the target, it is in 'WAIT_ENDBR' status, which can be read from MSR_IA32_U_CET. The status is part of a task's status before a signal is raised and preserved in the signal frame. It is restored for sigreturn. IBT state machine is described in Intel SDM Vol. 1, Sec. 18.3. Signed-off-by: Yu-cheng Yu <redacted>
Reviewed-by: Kees Cook <redacted> -- Kees Cook