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authorKrzysztof Kozlowski <k.kozlowski@samsung.com>2016-05-17 08:02:06 +0200
committerLinus Walleij <linus.walleij@linaro.org>2016-05-30 09:41:49 +0200
commita0ee2ac039c012062d91fbb324c3068c089a9380 (patch)
tree0b157cfa30f87ab6e30961b8d83f1900f12833ad
parent2f94ced704c488d0bf6b6efe4969a21089dae72d (diff)
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pinctrl: samsung: Suppress unbinding to prevent theoretical attacks
Although unbinding a pinctrl driver requires root privileges but it still might be used theoretically in certain attacks (by triggering NULL pointer exception or memory corruption). Samsung pincontrol drivers are essential for system operation so their removal is not expected. They do not implement remove() driver callback and they are not buildable as modules. Suppression of the unbinding will prevent triggering NULL pointer exception like this (Odroid XU3): $ echo 13400000.pinctrl > /sys/bus/platform/drivers/samsung-pinctrl/unbind $ cat /sys/kernel/debug/gpio Unable to handle kernel NULL pointer dereference at virtual address 00000c44 pgd = ec41c000 [00000c44] *pgd=6d448835, *pte=00000000, *ppte=00000000 Internal error: Oops: 17 [#1] PREEMPT SMP ARM (samsung_gpio_get) from [<c034f9a0>] (gpiolib_seq_show+0x1b0/0x26c) (gpiolib_seq_show) from [<c01fb8c0>] (seq_read+0x304/0x4b8) (seq_read) from [<c02dbc78>] (full_proxy_read+0x4c/0x64) (full_proxy_read) from [<c01d9fb0>] (__vfs_read+0x2c/0x110) (__vfs_read) from [<c01db400>] (vfs_read+0x8c/0x110) (vfs_read) from [<c01db4c4>] (SyS_read+0x40/0x8c) (SyS_read) from [<c01078c0>] (ret_fast_syscall+0x0/0x3c) Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
-rw-r--r--drivers/pinctrl/samsung/pinctrl-exynos5440.c1
-rw-r--r--drivers/pinctrl/samsung/pinctrl-samsung.c1
2 files changed, 2 insertions, 0 deletions
diff --git a/drivers/pinctrl/samsung/pinctrl-exynos5440.c b/drivers/pinctrl/samsung/pinctrl-exynos5440.c
index fb71fc3e5aa0..3000df80709f 100644
--- a/drivers/pinctrl/samsung/pinctrl-exynos5440.c
+++ b/drivers/pinctrl/samsung/pinctrl-exynos5440.c
@@ -998,6 +998,7 @@ static struct platform_driver exynos5440_pinctrl_driver = {
.driver = {
.name = "exynos5440-pinctrl",
.of_match_table = exynos5440_pinctrl_dt_match,
+ .suppress_bind_attrs = true,
},
};
diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c
index ed0b70881e19..513fe6b23248 100644
--- a/drivers/pinctrl/samsung/pinctrl-samsung.c
+++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
@@ -1274,6 +1274,7 @@ static struct platform_driver samsung_pinctrl_driver = {
.driver = {
.name = "samsung-pinctrl",
.of_match_table = samsung_pinctrl_dt_match,
+ .suppress_bind_attrs = true,
},
};