Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH] driver core: fix driver_set_override() issue with empty strings | Date | Thu, 1 Sep 2022 18:37:34 +0200 |
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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); -- 2.37.3
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