| Message ID | 20240517101227.12118-1-hagarhem@amazon.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3] gpio: prevent potential speculation leaks in gpio_device_get_desc() | expand |
On Fri, May 17, 2024 at 10:12:27AM +0000, Hagar Hemdan wrote: > Userspace may trigger a speculative read of an address outside the gpio > descriptor array. > Users can do that by calling gpio_ioctl() with an offset out of range. > Offset is copied from user and then used as an array index to get > the gpio descriptor without sanitization in gpio_device_get_desc(). > > This change ensures that the offset is sanitized by using > array_index_nospec() to mitigate any possibility of speculative > information leaks. > > This bug was discovered and resolved using Coverity Static Analysis > Security Testing (SAST) by Synopsys, Inc. > > Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL") I still don't think this Fixes commit is right, and that would impact where this gets backported to, but Bart can weigh in on that. Cheers, Kent. > Signed-off-by: Hagar Hemdan <hagarhem@amazon.com> > --- > v3: update the commit mesg > --- > drivers/gpio/gpiolib.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index fa50db0c3605..b58e4fe78cec 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -17,6 +17,7 @@ > #include <linux/list.h> > #include <linux/lockdep.h> > #include <linux/module.h> > +#include <linux/nospec.h> > #include <linux/of.h> > #include <linux/pinctrl/consumer.h> > #include <linux/seq_file.h> > @@ -201,7 +202,7 @@ gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum) > if (hwnum >= gdev->ngpio) > return ERR_PTR(-EINVAL); > > - return &gdev->descs[hwnum]; > + return &gdev->descs[array_index_nospec(hwnum, gdev->ngpio)]; > } > EXPORT_SYMBOL_GPL(gpio_device_get_desc); > > -- > 2.40.1 >
On Fri, May 17, 2024 at 08:49:11PM +0800, Kent Gibson wrote: > On Fri, May 17, 2024 at 10:12:27AM +0000, Hagar Hemdan wrote: > > Userspace may trigger a speculative read of an address outside the gpio > > descriptor array. > > Users can do that by calling gpio_ioctl() with an offset out of range. > > Offset is copied from user and then used as an array index to get > > the gpio descriptor without sanitization in gpio_device_get_desc(). > > > > This change ensures that the offset is sanitized by using > > array_index_nospec() to mitigate any possibility of speculative > > information leaks. > > > > This bug was discovered and resolved using Coverity Static Analysis > > Security Testing (SAST) by Synopsys, Inc. > > > > Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL") > > I still don't think this Fixes commit is right, and that would impact > where this gets backported to, but Bart can weigh in on that. > > Cheers, > Kent. > yes, this Fixes commit is wrong. Stable trees need another fix patch. I will remove this Fixes commit in the next revision. Thanks, Hagar > > > Signed-off-by: Hagar Hemdan <hagarhem@amazon.com> > > --- > > v3: update the commit mesg > > --- > > drivers/gpio/gpiolib.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > > index fa50db0c3605..b58e4fe78cec 100644 > > --- a/drivers/gpio/gpiolib.c > > +++ b/drivers/gpio/gpiolib.c > > @@ -17,6 +17,7 @@ > > #include <linux/list.h> > > #include <linux/lockdep.h> > > #include <linux/module.h> > > +#include <linux/nospec.h> > > #include <linux/of.h> > > #include <linux/pinctrl/consumer.h> > > #include <linux/seq_file.h> > > @@ -201,7 +202,7 @@ gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum) > > if (hwnum >= gdev->ngpio) > > return ERR_PTR(-EINVAL); > > > > - return &gdev->descs[hwnum]; > > + return &gdev->descs[array_index_nospec(hwnum, gdev->ngpio)]; > > } > > EXPORT_SYMBOL_GPL(gpio_device_get_desc); > > > > -- > > 2.40.1 > >
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index fa50db0c3605..b58e4fe78cec 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -17,6 +17,7 @@ #include <linux/list.h> #include <linux/lockdep.h> #include <linux/module.h> +#include <linux/nospec.h> #include <linux/of.h> #include <linux/pinctrl/consumer.h> #include <linux/seq_file.h> @@ -201,7 +202,7 @@ gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum) if (hwnum >= gdev->ngpio) return ERR_PTR(-EINVAL); - return &gdev->descs[hwnum]; + return &gdev->descs[array_index_nospec(hwnum, gdev->ngpio)]; } EXPORT_SYMBOL_GPL(gpio_device_get_desc);
Userspace may trigger a speculative read of an address outside the gpio descriptor array. Users can do that by calling gpio_ioctl() with an offset out of range. Offset is copied from user and then used as an array index to get the gpio descriptor without sanitization in gpio_device_get_desc(). This change ensures that the offset is sanitized by using array_index_nospec() to mitigate any possibility of speculative information leaks. This bug was discovered and resolved using Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc. Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL") Signed-off-by: Hagar Hemdan <hagarhem@amazon.com> --- v3: update the commit mesg --- drivers/gpio/gpiolib.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)