On Tue, May 24, 2016 at 12:43:29PM +0100, Stuart Henderson wrote:
> On 2016/05/24 14:34, Artturi Alm wrote:
> > On Tue, May 24, 2016 at 11:31:31AM +0100, Stuart Henderson wrote:
> > > On 2016/05/24 11:47, Artturi Alm wrote:
> > > > >How-To-Repeat:
> > > > modern browser
> > > ..
> > > > chrome(83796): mmap: mandatory W^X
> > > > chrome(19957): mmap: mandatory W^X
> > > > firefox(74606): mmap: mandatory W^X
> > > > chrome(6007): mmap: mandatory W^X
> > > > chrome(50373): mmap: mandatory W^X
> > >
> > > Any idea what you were doing in Firefox when this triggered?
> > >
> > it was totally fresh firefox install w/no existing config nor plugins/addons
> > w/e they are on that browser, figured i would uninstall once i found it
> > suffering from mmap: mandatory W^X too, however i believe it was
> > running/idling with these tabs:
> > https://github.com
> > http://ftp.openbsd.org/
> > https://www.google.com/
> > http://www.openbsd.org/faq/
> > http://cvsweb.openbsd.org/cgi-bin/cvsweb/
> >
> > can still provide exact urls off-list if you want, as it still seemed to
> > launch with same set of tabs i left it running with while i was testing it
> > before reboot to get rid of the msg.
>
> Any chance you could try it with this diff and obtain a
> backtrace? Knowing browsers it might not be useful anyway, but
> it may just give us some clues..
>
Ran with it for rest of the day, and was unable to reproduce w/firefox alone.
Gave it quite a beating managing to get a couple of non-W^X related .cores,
but as chrome was out of the game due diff below making it go just "aww snap",
i'd say the system environment was too different to earlier by +100chrome
processes and whatever i do while messing around src.
Did ran into comment by some ffdeveloper acknowledging some potential race(s?),
but don't remember how old the comment was, likely irrelevant to this case,
just mentioning.
-Artturi
> Index: uvm_mmap.c
> ===================================================================
> RCS file: /cvs/src/sys/uvm/uvm_mmap.c,v
> retrieving revision 1.125
> diff -u -p -u -r1.125 uvm_mmap.c
> --- uvm_mmap.c 11 May 2016 21:52:51 -0000 1.125
> +++ uvm_mmap.c 20 May 2016 20:40:40 -0000
> @@ -351,6 +351,10 @@ sys_mmap(struct proc *p, void *v, regist
> */
> if ((prot & PROT_MASK) != prot)
> return (EINVAL);
> + if ((prot & (PROT_EXEC|PROT_WRITE)) == (PROT_EXEC|PROT_WRITE)) {
> + printf("%s(%d): mmap: mandatory W^X\n", p->p_comm, p->p_pid);
> + return (EACCES);
> + }
> if ((flags & MAP_FLAGMASK) != flags)
> return (EINVAL);
> if (flags & MAP_OLDCOPY)
> @@ -664,6 +668,11 @@ sys_mprotect(struct proc *p, void *v, re
>
> if ((prot & PROT_MASK) != prot)
> return (EINVAL);
> +
> + if ((prot & (PROT_EXEC|PROT_WRITE)) == (PROT_EXEC|PROT_WRITE)) {
> + printf("%s(%d): mprotect: mandatory W^X\n", p->p_comm,
> p->p_pid);
> + sigexit(p, SIGSEGV);
> + }
>
> error = pledge_protexec(p, prot);
> if (error)
