Messages in this thread | | | Date | Thu, 06 Mar 2008 19:13:20 +0100 | From | Paolo Bonzini <> | Subject | Re: RELEASE BLOCKER: Linux doesn't follow x86/x86-64 ABI wrt direction flag |
| |
Olivier Galibert wrote: > On Thu, Mar 06, 2008 at 09:58:41AM -0800, Joe Buck wrote: >> If the kernel allows state to leak from one process to another, >> for example from a process running as root to a process running as an >> ordinary user, it's a bug, with possible security implications. > > I don't think that it is relevant in your case. If you have the > signal handler in something that does not share the VM with the > interrupted thread, you will have a context switch which is supposed > to store the direction flag and restore the one from the handling > thread. If you share the VM there is no context switch but you have > access to the exact same memory with the exact same rights, making the > leak irrelevant.
A process can send a signal via kill. IOW, a malicious process can *control when the process would be interrupted* in order to get it into the signal handler with DF=1.
Paolo
| |