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-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20191127203027.261800350@linuxfoundation.org>
Date:   Wed, 27 Nov 2019 21:30:26 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Mattias Jacobsson <2pi@....nu>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 043/151] USB: misc: appledisplay: fix backlight update_status return code

From: Mattias Jacobsson <2pi@....nu>

[ Upstream commit 090158555ff8d194a98616034100b16697dd80d0 ]

Upon success the update_status handler returns a positive number
corresponding to the number of bytes transferred by usb_control_msg.
However the return code of the update_status handler should indicate if
an error occurred(negative) or how many bytes of the user's input to sysfs
that was consumed. Return code zero indicates all bytes were consumed.

The bug can for example result in the update_status handler being called
twice, the second time with only the "unconsumed" part of the user's input
to sysfs. Effectively setting an incorrect brightness.

Change the update_status handler to return zero for all successful
transactions and forward usb_control_msg's error code upon failure.

Signed-off-by: Mattias Jacobsson <2pi@....nu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/usb/misc/appledisplay.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/misc/appledisplay.c b/drivers/usb/misc/appledisplay.c
index b8092bcf89a29..140af7754c1e6 100644
--- a/drivers/usb/misc/appledisplay.c
+++ b/drivers/usb/misc/appledisplay.c
@@ -160,8 +160,11 @@ static int appledisplay_bl_update_status(struct backlight_device *bd)
 		pdata->msgdata, 2,
 		ACD_USB_TIMEOUT);
 	mutex_unlock(&pdata->sysfslock);
-	
-	return retval;
+
+	if (retval < 0)
+		return retval;
+	else
+		return 0;
 }
 
 static int appledisplay_bl_get_brightness(struct backlight_device *bd)
-- 
2.20.1



Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ