The join_thread() syscall is not supposed to be interruptible by
signals, but it was. And since the process death mechanism piggybacked
on signal interrupts, it was possible to interrupt a pthread_join() by
killing the process that was doing it, leading to confusing due to some
assumptions being made by Thread::finalize() for threads that have a
pending joiner.
This patch fixes the issue by making "interrupted by death" a distinct
block result separate from "interrupted by signal". Then we handle that
state in join_thread() and tidy things up so that thread finalization
doesn't get confused by the pending joiner being gone.
Test: Tests/Kernel/null-deref-crash-during-pthread_join.cpp
This fixes a null RefPtr deref (which asserts) in the scheduler if a
file descriptor being select()'ed is closed by a second thread while
blocked in select().
Test: Kernel/null-deref-close-during-select.cpp
This patch fixes some issues with the mmap() and mprotect() syscalls,
neither of whom were checking the permission bits of the underlying
files when mapping an inode MAP_SHARED.
This made it possible to subvert execution of any running program
by simply memory-mapping its executable and replacing some of the code.
Test: Kernel/mmap-write-into-running-programs-executable-file.cpp
This encourages callers to strongly reference file descriptions while
working with them.
This fixes a use-after-free issue where one thread would close() an
open fd while another thread was blocked on it becoming readable.
Test: Kernel/uaf-close-while-blocked-in-read.cpp
