Messages in this thread | | | Date | Fri, 26 Oct 2007 13:30:42 +0100 (BST) | From | Hugh Dickins <> | Subject | Re: [PATCH] [RFC] brk randomization: compute RLIMIT_DATA properly (was Re: x86: randomize brk() and RLIMIT_DATA) |
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On Fri, 26 Oct 2007, Jiri Kosina wrote: > On Fri, 26 Oct 2007, Hugh Dickins wrote: > > > > - if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) > > > + if (rlim < RLIM_INFINITY && brk - mm->start_data - > > > + (mm->start_brk - mm->end_data) > rlim) > > I find the order in that test mysterious. > > I agree that the order you proposed is easier to understand on the first > sight. > > > From: Jiri Kosina <jkosina@suse.cz> > > brk randomization: compute RLIMIT_DATA properly > > In cases of heap area placed at randomly-generated offset from > mm->end_data (arch_randomize_brk()), we need to subtract the value of the > offset for setrlimit(RLIMIT_DATA) to work properly -- otherwise we count > the unoccupied memory between mm->end_data and mm->start_brk as occupied. > > Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Hugh Dickins <hugh@veritas.com>
> > diff --git a/mm/mmap.c b/mm/mmap.c > index facc1a7..673ac7d 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -251,7 +251,8 @@ asmlinkage unsigned long sys_brk(unsigned long brk) > * not page aligned -Ram Gupta > */ > rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; > - if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) > + if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + > + (mm->end_data - mm->start_data) > rlim) > goto out; > > newbrk = PAGE_ALIGN(brk); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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