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gpio: prevent potential speculation leaks in gpio_device_get_desc()

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commit d795848ecce24a75dfd46481aee066ae6fe39775 upstream.

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.

Signed-off-by: Hagar Hemdan <hagarhem@amazon.com>
Link: https://lore.kernel.org/r/20240523085332.1801-1-hagarhem@amazon.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@witekio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hagar Hemdan 2024-05-23 08:53:32 +00:00 committed by Ksawlii
parent 7d63704581
commit fc35a684e9
1 changed files with 2 additions and 1 deletions
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3
drivers/gpio/gpiolib.c
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@ -4,6 +4,7 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/irq.h> #include <linux/irq.h>
#include <linux/nospec.h>
#include <linux/spinlock.h> #include <linux/spinlock.h>
#include <linux/list.h> #include <linux/list.h>
#include <linux/device.h> #include <linux/device.h>
@ -147,7 +148,7 @@ struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc,
if (hwnum >= gdev->ngpio) if (hwnum >= gdev->ngpio)
return ERR_PTR(-EINVAL); return ERR_PTR(-EINVAL);
return &gdev->descs[hwnum]; return &gdev->descs[array_index_nospec(hwnum, gdev->ngpio)];
} }
EXPORT_SYMBOL_GPL(gpiochip_get_desc); EXPORT_SYMBOL_GPL(gpiochip_get_desc);