linux-kernel - [PATCH] gpiolib: fix bitmap operations related to line event watching

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 26 Feb 2020 14:53:23 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Kent Gibson <warthog618@...il.com>
Subject: [PATCH] gpiolib: fix bitmap operations related to line event watching

From: Bartosz Golaszewski <bgolaszewski@...libre.com>

When operating on the bits of watched_lines bitmap, we're using
desc_to_gpio() which returns the GPIO number from the global numberspace.
This leads to all sorts of memory corruptions and invalid behavior. We
should switch to using gpio_chip_hwgpio() instead.

Fixes: 51c1064e82e7 ("gpiolib: add new ioctl() for monitoring changes in line info")
Reported-by: Kent Gibson <warthog618@...il.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
---
 drivers/gpio/gpiolib.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a5cd1b4abe6f..5cc80f6f79e0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1261,7 +1261,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			return -EFAULT;
 
 		if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL)
-			set_bit(desc_to_gpio(desc), priv->watched_lines);
+			set_bit(gpio_chip_hwgpio(desc), priv->watched_lines);
 
 		return 0;
 	} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
@@ -1276,7 +1276,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (IS_ERR(desc))
 			return PTR_ERR(desc);
 
-		clear_bit(desc_to_gpio(desc), priv->watched_lines);
+		clear_bit(gpio_chip_hwgpio(desc), priv->watched_lines);
 		return 0;
 	}
 	return -EINVAL;
@@ -1304,7 +1304,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
 	struct gpio_desc *desc = data;
 	int ret;
 
-	if (!test_bit(desc_to_gpio(desc), priv->watched_lines))
+	if (!test_bit(gpio_chip_hwgpio(desc), priv->watched_lines))
 		return NOTIFY_DONE;
 
 	memset(&chg, 0, sizeof(chg));
-- 
2.25.0