Messages in this thread | | | Date | Thu, 1 Sep 2022 09:56:02 -0700 | From | Stephen Hemminger <> | Subject | Re: [PATCH] driver core: fix driver_set_override() issue with empty strings |
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On Thu, 1 Sep 2022 18:37:34 +0200 Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> Python likes to send an empty string for some sysfs files, including the > driver_override field. When commit 23d99baf9d72 ("PCI: Use > driver_set_override() instead of open-coding") moved the PCI core to use > the driver core function instead of hand-rolling their own handler, this > showed up as a regression from some userspace tools, like DPDK. > > Fix this up by actually looking at the length of the string first > instead of trusting that userspace got it correct. > > Reported-by: Stephen Hemminger <stephen@networkplumber.org> > Fixes: 23d99baf9d72 ("PCI: Use driver_set_override() instead of open-coding") > Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: "Rafael J. Wysocki" <rafael@kernel.org> > Cc: Andy Shevchenko <andy.shevchenko@gmail.com> > Cc: stable <stable@kernel.org> > Tested-by: Huisong Li <lihuisong@huawei.com> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > --- > drivers/base/driver.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/base/driver.c b/drivers/base/driver.c > index 15a75afe6b84..676b6275d5b5 100644 > --- a/drivers/base/driver.c > +++ b/drivers/base/driver.c > @@ -63,6 +63,12 @@ int driver_set_override(struct device *dev, const char **override, > if (len >= (PAGE_SIZE - 1)) > return -EINVAL; > > + /* > + * Compute the real length of the string in case userspace sends us a > + * bunch of \0 characters like python likes to do. > + */ > + len = strlen(s); > + > if (!len) { > /* Empty string passed - clear override */ > device_lock(dev);
Thanks for addressing this.
Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
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