Patch "gpio: 74x164: Fix crash during .remove()" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    gpio: 74x164: Fix crash during .remove()

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     gpio-74x164-fix-crash-during-.remove.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri Feb 23 11:45:09 CET 2018
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Tue, 21 Nov 2017 15:18:10 +0100
Subject: gpio: 74x164: Fix crash during .remove()

From: Geert Uytterhoeven <geert+renesas@glider.be>


[ Upstream commit a158531f3c92467df0e93e000d58185acae78a6e ]

Commit 7ebc194d0fd4bb0f ("gpio: 74x164: Introduce 'enable-gpios'
property") added a new member gpiod_oe to the end of the struct
gen_74x164_chip, after the zero-length buffer array.

However, this buffer is a flexible array, allocated together with the
structure during .probe().  As the buffer is no longer the last member,
writing to it corrupts the newly added member after it.
During device removal, the corrupted member will be used as a pointer,
leading to a crash.

This went unnoticed, as the flexible array was declared as "buffer[0]"
instead of "buffer[]", and thus did not trigger a "flexible array member
not at end of struct" error from gcc.

Move the gpiod_oe field up to fix this, and drop the zero from the array
size to prevent future similar bugs.

Fixes: 7ebc194d0fd4bb0f ("gpio: 74x164: Introduce 'enable-gpios' property")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpio/gpio-74x164.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpio/gpio-74x164.c
+++ b/drivers/gpio/gpio-74x164.c
@@ -23,6 +23,7 @@
 struct gen_74x164_chip {
 	struct gpio_chip	gpio_chip;
 	struct mutex		lock;
+	struct gpio_desc	*gpiod_oe;
 	u32			registers;
 	/*
 	 * Since the registers are chained, every byte sent will make
@@ -31,8 +32,7 @@ struct gen_74x164_chip {
 	 * register at the end of the transfer. So, to have a logical
 	 * numbering, store the bytes in reverse order.
 	 */
-	u8			buffer[0];
-	struct gpio_desc	*gpiod_oe;
+	u8			buffer[];
 };
 
 static int __gen_74x164_write_config(struct gen_74x164_chip *chip)


Patches currently in stable-queue which might be from geert+renesas@glider.be are

queue-4.14/gpio-74x164-fix-crash-during-.remove.patch
queue-4.14/pci-rcar-fix-use-after-free-in-probe-error-path.patch