Re: [PATCH] alpha: Add extra switch_stack frames in exit, exec, and kernel threads
From: Al Viro <viro@zeniv.linux.org.uk>
Date: 2021-06-16 20:51:07
Also in:
linux-alpha, linux-m68k, lkml
Possibly related (same subject, not in this thread)
- 2021-06-16 · Re: [PATCH] alpha: Add extra switch_stack frames in exit, exec, and kernel threads · Eric W. Biederman <hidden>
On Tue, Jun 15, 2021 at 02:36:38PM -0500, Eric W. Biederman wrote:
While thinking about the information leaks fixed in 77f6ab8b7768
("don't dump the threads that had been already exiting when zapped.")
I realized the problem is much more general than just coredumps and
exit_mm. We have io_uring threads, PTRACE_EVENT_EXEC and
PTRACE_EVENT_EXIT where ptrace is allowed to access userspace
registers, but on some architectures has not saved them.Wait a sec. To have anything happen on PTRACE_EVENT_EXEC, you need the fucker traced. *IF* you want to go that way, at least make it conditional upon the same thing.