Re: [PATCH 2/4] KASLR: Parse all memmap entries in cmdline

Baoquan He
2017-04-19T00:07:09Z

On 04/18/17 at 04:32pm, Kees Cook wrote:
> On Tue, Apr 18, 2017 at 3:52 PM, Baoquan He <bhe@redhat.com> wrote:
> > On 04/18/17 at 01:22pm, Kees Cook wrote:
> >> > +#define COMMAND_LINE_SIZE 256
> >> > +static int handle_mem_memmap(void)
> >> > +{
> >> > + char *args = (char *)get_cmd_line_ptr();
> >> > + char tmp_cmdline[COMMAND_LINE_SIZE];
> >>
> >> Can't this use a dynamic allocation instead of the 256 limit?
> >
> > This is in boot/compressed code, no mm allocator built yet? Am I right?
>
> misc.c uses malloc for phdrs, and the boot_heap is create to build an
> area for those calls, see include/linux/decompress/mm.h. I *think* it
> should be safe to use malloc here. It should be a pretty small
> allocation normally.

Yes, didn't notice this. Will use it to do dynamic malloc.
Thanks for telling!