ARMv8.1-M: Add task dedicated PAC key support #1195
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Some declarations in portasm.h and FreeRTOS.h will cause build errors if it's not understood by the assembler. For example the 'extern' keyword. To avoid these errors guard any such code inside a #ifdef #endif block so the code is included in C files but excluded by the preprocessor in assembly files. Signed-off-by: Ahmed Ismail <[email protected]>
ARMv8-M TrustZone variant registers stacking procedure is modified to be consistent with the NTZ port variant where one `stmdb` instruction is used instead of using 'subs' instruction along with `stmia` instruction, also, this result in more efficient context switching handling (lower latency). Signed-off-by: Ahmed Ismail <[email protected]>
To harden the security, each task is assigned a dedicated PAC key, so that attackers needs to guess the all the tasks' PAC keys right to exploit the system using Return Oriented Programming. The kernel is now updated to support the following: * A PAC key set with a random number generated and is pushed onto the task's stack when a task is created. * As part of scheduling, the task's PAC key is stacked/unstacked to/from the task's stack when a task is unscheduled/scheduled from/to run. Signed-off-by: Ahmed Ismail <[email protected]>
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urutva
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Nov 19, 2024
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Thank you for your contribution @AhmedIsmail02! I have reviewed the code and I have the following suggestions -
All of my suggestions are in the following patch - 0001-Code-review-suggestions.patch. Please take a look and let me know what you think. |
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Description
To harden the security, each task is assigned with a dedicated PAC key, so that attackers needs to get the all the PAC keys right to exploit the system using Return Oriented Programming. The kernel is updated to support the following:
Test Steps
Checklist:
Related Issue
Blocks FreeRTOS/FreeRTOS-Partner-Supported-Demos#19
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