Messages in this thread | | | From | Tomeu Vizoso <> | Date | Thu, 3 Sep 2015 09:57:02 +0200 | Subject | Re: [PATCH] clk_register_clkdev: handle callers needing format string |
| |
On 5 August 2015 at 15:09, Tomeu Vizoso <tomeu@tomeuvizoso.net> wrote: > On 31 July 2015 at 21:03, Kees Cook <keescook@chromium.org> wrote: >> On Fri, Jul 31, 2015 at 2:13 AM, Tomeu Vizoso <tomeu@tomeuvizoso.net> wrote: >>> On 25 July 2015 at 01:20, Kees Cook <keescook@chromium.org> wrote: >>>> Many callers either use NULL or const strings for the third argument of >>>> clk_register_clkdev. For those that do not, this is a risk for format >>>> strings being accidentally processed (for example in device names). This >>>> adds the missing "%s" arguments to make sure format strings will not leak >>>> into the clkdev. >>>> >>>> Signed-off-by: Kees Cook <keescook@chromium.org> >>>> --- >>> >>> [...] >>> >>>> diff --git a/drivers/clk/tegra/clk.c b/drivers/clk/tegra/clk.c >>>> index 41cd87c67be6..97d9fb7e89ad 100644 >>>> --- a/drivers/clk/tegra/clk.c >>>> +++ b/drivers/clk/tegra/clk.c >>>> @@ -296,7 +296,7 @@ void __init tegra_register_devclks(struct tegra_devclk *dev_clks, int num) >>>> >>>> for (i = 0; i < num; i++, dev_clks++) >>>> clk_register_clkdev(clks[dev_clks->dt_id], dev_clks->con_id, >>>> - dev_clks->dev_id); >>>> + "%s", dev_clks->dev_id); >>> >>> This causes clocks to be registered with a dev_id string of "(null)", >>> which is causing lookups that used to succeed before to fail. >> >> Oh yuck. Yeah, clk_register_clkdev handles a NULL argument differently >> than other format-string style functions. Using >> clk_register_clkdev(..., dev_clks->dev_id ? "%s" : NULL, >> dev_clks->dev_id) seems really ugly to work around this, though. >> Perhaps the format string capability should be removed? > > Yeah, that sounds good to me. At least, I don't see as that good of an > idea to save a few lines of code by making the API so prone to > mistakes. > > Could this patch be removed from linux-next in the meantime?
Stephen, Mike,
the Tegra portion of this patch is wrong because it registers some clocks with a dev_id of "(null)", which is really inconvenient when debugging because one cannot tell from the logs if it's NULL or that actual string.
Could this be reverted?
Thanks,
Tomeu
> Thanks, > > Tomeu > >> -Kees >> >> -- >> Kees Cook >> Chrome OS Security
| |