Messages in this thread | | | Date | Mon, 21 Sep 1998 01:18:48 +0100 | From | Jamie Lokier <> | Subject | Re: [PATCH] (please check) Potential security fix for i386/kernel/ptrace.c |
| |
On Sun, Sep 20, 1998 at 04:09:00PM -0700, Linus Torvalds wrote: > It should actually be safe. The debug trap handler is careful to not > aquire any locks (ie no deadlock situations), and should alwasy ignore > events from kernel space.
It would still cause a slowdown, perhaps somewhere critical (interrupt handler, syscall entry point etc). If a breakpoint is placed in encryption code or the /dev/random driver, the timing effects would leak information.
What happens if a breakpoint is placed in the debug trap handler, the syscall entry point, ret_from_syscall etc.?
> The patch looks fine regardless, but I want to have a robust system, and > that does mean that even if somebody can trigger a debug trap in the > kernel (easy to do by just having a read() system call write over > something you want to get the trap on in user mode) then the kernel should > not really have to care anyway.
It does make sense for the debug trap to be robust as well.
-- Jamie
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |