Messages in this thread | | | Date | Mon, 20 Apr 2020 15:41:40 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] fs/binfmt_elf.c: allocate initialized memory in fill_thread_core_info() |
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On Mon, Apr 20, 2020 at 03:33:52PM -0700, Andrew Morton wrote: > On Sun, 19 Apr 2020 12:08:48 +0200 glider@google.com wrote: > > > KMSAN reported uninitialized data being written to disk when dumping > > core. As a result, several kilobytes of kmalloc memory may be written to > > the core file and then read by a non-privileged user.
Ewww. That's been there for 12 years. Did something change in regset_size() or regset->get()? Do you know what leaves the hole?
> > > > ... > > > > --- a/fs/binfmt_elf.c > > +++ b/fs/binfmt_elf.c > > @@ -1733,7 +1733,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, > > (!regset->active || regset->active(t->task, regset) > 0)) { > > int ret; > > size_t size = regset_size(t->task, regset); > > - void *data = kmalloc(size, GFP_KERNEL); > > + void *data = kzalloc(size, GFP_KERNEL); > > if (unlikely(!data)) > > return 0; > > ret = regset->get(t->task, regset, > > This seems to be a quite easy way of exposing quite a large amount of > kernel memory contents, so I think I'll add a cc:stable to this patch?
Yes please.
Acked-by: Kees Cook <keescook@chromium.org>
-Kees
-- Kees Cook
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