On 5/15/23 06:05, jeffxu@xxxxxxxxxxxx wrote: > We're using PKU for in-process isolation to enforce control-flow integrity > for a JIT compiler. In our threat model, an attacker exploits a > vulnerability and has arbitrary read/write access to the whole process > space concurrently to other threads being executed. This attacker can > manipulate some arguments to syscalls from some threads. This all sounds like it hinges on the contents of PKRU in the attacker thread. Could you talk a bit about how the attacker is prevented from running WRPKRU, XRSTOR or compelling the kernel to write to PKRU like at sigreturn?