Re: [PATCH] Fix a potential abuse of seq_printf() format string in drivers
From: Greg Kroah-Hartman
Date: Wed Nov 20 2024 - 14:29:10 EST
On Wed, Nov 20, 2024 at 10:12:40AM -0800, Kees Cook wrote:
> On Wed, Nov 20, 2024 at 08:35:38AM +0100, Linus Walleij wrote:
> > On Wed, Nov 20, 2024 at 6:31 AM David Wang <00107082@xxxxxxx> wrote:
> >
> > > Using device name as format string of seq_printf() is proned to
> > > "Format string attack", opens possibility for exploitation.
> > > Seq_puts() is safer and more efficient.
> > >
> > > Signed-off-by: David Wang <00107082@xxxxxxx>
> >
> > Okay better get Kees' eye on this, he looks after string vulnerabilities.
> > (But I think you're right.)
>
> Agreed, this may lead to kernel memory content exposures. seq_puts()
> looks right.
>
> Reviewed-by: Kees Cook <kees@xxxxxxxxxx>
Wait, userspace "shouldn't" be controlling a device name, but odds are
there are some paths/subsystems that do this, ugh.
> To defend against this, it might be interesting to detect
> single-argument seq_printf() usage and aim it at seq_puts()
> automatically...
Yeah, that would be good to squash this type of issue.
> > > drivers/gpio/gpio-aspeed-sgpio.c | 2 +-
> > > drivers/gpio/gpio-aspeed.c | 2 +-
> > > drivers/gpio/gpio-ep93xx.c | 2 +-
> > > drivers/gpio/gpio-hlwd.c | 2 +-
> > > drivers/gpio/gpio-mlxbf2.c | 2 +-
> > > drivers/gpio/gpio-omap.c | 2 +-
> > > drivers/gpio/gpio-pca953x.c | 2 +-
> > > drivers/gpio/gpio-pl061.c | 2 +-
> > > drivers/gpio/gpio-tegra.c | 2 +-
> > > drivers/gpio/gpio-tegra186.c | 2 +-
> > > drivers/gpio/gpio-tqmx86.c | 2 +-
> > > drivers/gpio/gpio-visconti.c | 2 +-
> > > drivers/gpio/gpio-xgs-iproc.c | 2 +-
> > > drivers/irqchip/irq-gic.c | 2 +-
> > > drivers/irqchip/irq-mvebu-pic.c | 2 +-
> > > drivers/irqchip/irq-versatile-fpga.c | 2 +-
> > > drivers/pinctrl/bcm/pinctrl-iproc-gpio.c | 2 +-
> > > drivers/pinctrl/mvebu/pinctrl-armada-37xx.c | 2 +-
> > > drivers/pinctrl/pinctrl-mcp23s08.c | 2 +-
> > > drivers/pinctrl/pinctrl-stmfx.c | 2 +-
> > > drivers/pinctrl/pinctrl-sx150x.c | 2 +-
> > > drivers/pinctrl/renesas/pinctrl-rzg2l.c | 2 +-
> >
> > Can you split this in three patches per-subsystem?
> > One for gpio, one for irqchip and one for pinctrl?
> >
> > Then send to each subsystem maintainer and CC kees on
> > each.
> >
> > I'm just the pinctrl maintainer. The rest can be found with
> > scripts/get_maintainer.pl.
>
> Oof. That's a lot of work for a mechanical change like this. Perhaps
> Greg KH can take it directly to the drivers tree instead?
I can take it all, as-is, right now, if you want me to. Just let me
know.
thanks,
greg k-h