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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andrea Righi <righi.andrea@gmail.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	Sam Ravnborg <sam@ravnborg.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Daniel Thompson <daniel.thompson@linaro.org>,
	Peter Rosin <peda@axentia.se>,
	Jani Nikula <jani.nikula@intel.com>,
	Gerd Hoffmann <kraxel@redhat.com>,
	dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH v2] fbdev: potential information leak in do_fb_ioctl()
Date: Mon, 13 Jan 2020 14:08:14 +0300	[thread overview]
Message-ID: <20200113100132.ixpaymordi24n3av@kili.mountain> (raw)
In-Reply-To: <fd4e6f01-074b-def7-7ffb-9a9197930c31@samsung.com>

The "fix" struct has a 2 byte hole after ->ywrapstep and the
"fix = info->fix;" assignment doesn't necessarily clear it.  It depends
on the compiler.  The solution is just to replace the assignment with an
memcpy().

Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2:  Use memcpy()

 drivers/video/fbdev/core/fbmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index d04554959ea7..bb8d8dbc0461 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1115,7 +1115,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
 		break;
 	case FBIOGET_FSCREENINFO:
 		lock_fb_info(info);
-		fix = info->fix;
+		memcpy(&fix, &info->fix, sizeof(fix));
 		if (info->flags & FBINFO_HIDE_SMEM_START)
 			fix.smem_start = 0;
 		unlock_fb_info(info);
-- 
2.11.0


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>,
	Gerd Hoffmann <kraxel@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
	Jani Nikula <jani.nikula@intel.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sam Ravnborg <sam@ravnborg.org>, Peter Rosin <peda@axentia.se>,
	Andrea Righi <righi.andrea@gmail.com>
Subject: [PATCH v2] fbdev: potential information leak in do_fb_ioctl()
Date: Mon, 13 Jan 2020 11:08:14 +0000	[thread overview]
Message-ID: <20200113100132.ixpaymordi24n3av@kili.mountain> (raw)
In-Reply-To: <fd4e6f01-074b-def7-7ffb-9a9197930c31@samsung.com>

The "fix" struct has a 2 byte hole after ->ywrapstep and the
"fix = info->fix;" assignment doesn't necessarily clear it.  It depends
on the compiler.  The solution is just to replace the assignment with an
memcpy().

Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2:  Use memcpy()

 drivers/video/fbdev/core/fbmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index d04554959ea7..bb8d8dbc0461 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1115,7 +1115,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
 		break;
 	case FBIOGET_FSCREENINFO:
 		lock_fb_info(info);
-		fix = info->fix;
+		memcpy(&fix, &info->fix, sizeof(fix));
 		if (info->flags & FBINFO_HIDE_SMEM_START)
 			fix.smem_start = 0;
 		unlock_fb_info(info);
-- 
2.11.0

WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>,
	Gerd Hoffmann <kraxel@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
	Jani Nikula <jani.nikula@intel.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sam Ravnborg <sam@ravnborg.org>, Peter Rosin <peda@axentia.se>,
	Andrea Righi <righi.andrea@gmail.com>
Subject: [PATCH v2] fbdev: potential information leak in do_fb_ioctl()
Date: Mon, 13 Jan 2020 14:08:14 +0300	[thread overview]
Message-ID: <20200113100132.ixpaymordi24n3av@kili.mountain> (raw)
In-Reply-To: <fd4e6f01-074b-def7-7ffb-9a9197930c31@samsung.com>

The "fix" struct has a 2 byte hole after ->ywrapstep and the
"fix = info->fix;" assignment doesn't necessarily clear it.  It depends
on the compiler.  The solution is just to replace the assignment with an
memcpy().

Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2:  Use memcpy()

 drivers/video/fbdev/core/fbmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index d04554959ea7..bb8d8dbc0461 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1115,7 +1115,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
 		break;
 	case FBIOGET_FSCREENINFO:
 		lock_fb_info(info);
-		fix = info->fix;
+		memcpy(&fix, &info->fix, sizeof(fix));
 		if (info->flags & FBINFO_HIDE_SMEM_START)
 			fix.smem_start = 0;
 		unlock_fb_info(info);
-- 
2.11.0

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dri-devel@lists.freedesktop.org
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  reply	other threads:[~2020-01-13 11:10 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-29 18:23 [PATCH] fbdev: potential information leak in do_fb_ioctl() Dan Carpenter
2019-10-29 18:23 ` Dan Carpenter
2019-10-29 18:23 ` Dan Carpenter
2019-10-29 18:35 ` Joe Perches
2019-10-29 18:35   ` Joe Perches
2019-10-29 18:35   ` Joe Perches
2019-10-29 19:02 ` Eric W. Biederman
2019-10-29 19:02   ` Eric W. Biederman
2019-10-29 19:02   ` Eric W. Biederman
2019-10-30  7:43   ` Andrea Righi
2019-10-30  7:43     ` Andrea Righi
2019-10-30  7:43     ` Andrea Righi
2019-10-30 19:26     ` Eric W. Biederman
2019-10-30 19:26       ` Eric W. Biederman
2019-10-30 19:26       ` Eric W. Biederman
2019-10-30 20:12       ` Andrea Righi
2019-10-30 20:12         ` Andrea Righi
2019-10-30 20:12         ` Andrea Righi
2019-10-31 18:16         ` Joe Perches
2019-10-31 18:16           ` Joe Perches
2019-10-31 18:16           ` Joe Perches
2019-10-31 22:12           ` Eric W. Biederman
2019-10-31 22:12             ` Eric W. Biederman
2019-10-31 22:12             ` Eric W. Biederman
2020-01-03 13:07   ` Bartlomiej Zolnierkiewicz
2020-01-03 13:07     ` Bartlomiej Zolnierkiewicz
2020-01-03 13:07     ` Bartlomiej Zolnierkiewicz
2020-01-13 11:08     ` Dan Carpenter [this message]
2020-01-13 11:08       ` [PATCH v2] " Dan Carpenter
2020-01-13 11:08       ` Dan Carpenter
2020-01-15 14:31       ` Bartlomiej Zolnierkiewicz
2020-01-15 14:31         ` Bartlomiej Zolnierkiewicz
2020-01-15 14:31         ` Bartlomiej Zolnierkiewicz
2020-01-13 12:49     ` [PATCH] " Arnd Bergmann
2020-01-13 12:49       ` Arnd Bergmann
2020-01-13 12:49       ` Arnd Bergmann
2020-01-15 13:09       ` Bartlomiej Zolnierkiewicz
2020-01-15 13:09         ` Bartlomiej Zolnierkiewicz
2020-01-15 13:09         ` Bartlomiej Zolnierkiewicz
2020-01-15 13:16         ` Arnd Bergmann
2020-01-15 13:16           ` Arnd Bergmann
2020-01-15 13:16           ` Arnd Bergmann

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