CVSROOT: /cvs
Module name: src
Changes by: chel...@cvs.openbsd.org 2022/06/27 08:26:06
Modified files:
sys/kern : syscalls.master init_sysent.c
sys/sys : proc.h syscall.h syscallargs.h
sys/uvm : uvm_mmap.c
Log message:
kbind(2): unlock syscall, push kernel lock down to binding loop
- Rearrange the security check code in sys_kbind() so that we only
need to take the kernel lock once if we need to raise SIGILL.
- Protect process.ps_kbind_addr and process.ps_kbind_cookie with
process.ps_mtx. This is easier to do after the aforementioned
rearrangement. Under normal circumstances this isn't necessary:
the process is single-threaded when we initialize kbind(2).
But in stranger situations this brief mutex ensures that the
first thread to reach sys_kbind() initializes both variables.
- Wrap the binding loop with the kernel lock. We need to carefully
confirm that uvm_unmap_remove(), uvm_map_extract(), and
uvm_unmap_detach() are MP-safe in a subsequent patch before
completely removing the kernel lock from sys_kbind().
- Remove the kernel lock from kbind(2) in syscalls.master.
Prompted by mpi@, dlg@, and deraadt@. Current patch workshopped with
deraadt@. Based on a patch from dlg@.
With input from dlg@, bluhm@, mpi@, kettenis@, deraadt@, and
guenther@.
Thread: https://marc.info/?l=openbsd-tech&m=165274831829349&w=2
ok deraadt@ kettenis@ mpi@
