On Mon, Jan 27, 2014 at 5:02 PM, Ryan Mallon <rmal...@gmail.com> wrote: > On 28/01/14 11:39, Kees Cook wrote: >> If arguments are consumed without output when encountering %n, it >> could be used to benefit or improve information leak attacks that were >> exposed via a limited size buffer. Since %n is not used by the kernel, >> there is no reason to make an info leak attack any easier. > > I was thinking more like the following. Print the warning if %n is > detected in format_decode(), but otherwise just remove the handling of > %n outright and treat it like any other invalid format specifier. > Something like this completely untested patch. Thoughts?
I'd be totally fine with it. Minor typo in the comment before the WARN_ONCE (should be "its" instead of "it"), but otherwise looks good. Consider it: Acked-by: Kees Cook <keesc...@chromium.org> It builds and boots fine for me, FWIW. -Kees -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
