Messages in this thread | | | Subject | Re: [PATCH] vsprintf: Make "null" pointer dereference more robust | From | Andy Shevchenko <> | Date | Tue, 06 Mar 2018 11:56:25 +0200 |
| |
On Tue, 2018-03-06 at 10:25 +0100, Petr Mladek wrote: > On Mon 2018-03-05 16:16:37, Rasmus Villemoes wrote: > > On 2 March 2018 at 13:53, Petr Mladek <pmladek@suse.com> wrote:
> > > - if (!ptr && *fmt != 'K' && *fmt != 'x') { > > > + if ((unsigned long)ptr < PAGE_SIZE && *fmt != 'K' && *fmt > > > != 'x') { > > > > ISTM that accidentally passing an ERR_PTR would be just as likely as > > passing a NULL pointer (or some small offset from one), so if we do > > this, shouldn't the test also cover IS_ERR values? > > It would make perfect sense to catch IS_ERR_PTR(). Derefenrecing > such pointer cause crash. But it might be pretty confusing to print > "(null)" in this case. > > I would handle this in separate patch and print "(err)" or so. > Any volunteer to prepare the patch?
As I pointed out, we have already such check for %s in binary printf(). And it goes for "(null)". I'm not sure if changing that might break something.
-- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
| |