Messages in this thread | | | Date | Sat, 19 Nov 2022 09:05:28 +0100 | Subject | Re: [PATCH] rtc: msc313: Fix function prototype mismatch in msc313_rtc_probe() | From | Christophe JAILLET <> |
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Le 19/11/2022 à 00:31, Kees Cook a écrit : > With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), > indirect call targets are validated against the expected function > pointer prototype to make sure the call target is valid to help mitigate > ROP attacks. If they are not identical, there is a failure at run time, > which manifests as either a kernel panic or thread getting killed. > > msc313_rtc_probe() was passing clk_disable_unprepare() directly, which > did not have matching prototypes for devm_add_action_or_reset()'s callback > argument. Add a wrapper and remove the cast. > > This was found as a result of Clang's new -Wcast-function-type-strict > flag, which is more sensitive than the simpler -Wcast-function-type, > which only checks for type width mismatches. > > Reported-by: kernel test robot <lkp@intel.com> > Link: https://lore.kernel.org/lkml/202211041527.HD8TLSE1-lkp@intel.com > Cc: Daniel Palmer <daniel@thingy.jp> > Cc: Romain Perier <romain.perier@gmail.com> > Cc: Alessandro Zummo <a.zummo@towertech.it> > Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-rtc@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > drivers/rtc/rtc-msc313.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/rtc/rtc-msc313.c b/drivers/rtc/rtc-msc313.c > index f3fde013c4b8..36e3e77f303e 100644 > --- a/drivers/rtc/rtc-msc313.c > +++ b/drivers/rtc/rtc-msc313.c > @@ -177,6 +177,13 @@ static irqreturn_t msc313_rtc_interrupt(s32 irq, void *dev_id) > return IRQ_HANDLED; > } > > +static void msc313_clk_disable_unprepare(void *data) > +{ > + struct clk *clk = data; > + > + clk_disable_unprepare(clk); > +} > + > static int msc313_rtc_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > @@ -224,7 +231,7 @@ static int msc313_rtc_probe(struct platform_device *pdev) > return ret; > } > > - ret = devm_add_action_or_reset(dev, (void (*) (void *))clk_disable_unprepare, clk); > + ret = devm_add_action_or_reset(dev, msc313_clk_disable_unprepare, clk); > if (ret) > return ret; >
Hi,
another way to fix it, is to use devm_clk_get_enabled().
It removes some LoC instead of introducing some new ones and saves a few bytes of memory.
CJ
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