Tagged
#syscalls
2 posts
Technical · 10 min
The confused deputy
I planted a flag on a kernel-only page and wrote a ring-3 program to steal it. The CPU stopped the direct read cold — then my own syscall handed the flag over the moment it dereferenced a caller-chosen pointer. The one door the hardware cannot guard for you.
Read Technical · 9 min
The first wall
Ring 3, a syscall gate, and the two bits that turn 'the kernel is the only program' into 'the kernel runs code it doesn't trust.' The first time in this project that the hardware, not my kernel's goodwill, holds code back.
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