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From: Joe Perches <joe@perches.com>
To: Dan Carpenter <dan.carpenter@oracle.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Andrea Righi <righi.andrea@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	Sam Ravnborg <sam@ravnborg.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Peter Rosin <peda@axentia.se>, 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,
	security@kernel.org, Kees Cook <keescook@chromium.org>,
	Julia Lawall <Julia.Lawall@lip6.fr>
Subject: Re: [PATCH] fbdev: potential information leak in do_fb_ioctl()
Date: Tue, 29 Oct 2019 11:35:55 -0700	[thread overview]
Message-ID: <5a6f05cef45dbb4f77008b36d7a63b429f1519ec.camel@perches.com> (raw)
In-Reply-To: <20191029182320.GA17569@mwanda>

On Tue, 2019-10-29 at 21:23 +0300, Dan Carpenter wrote:
> 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.
[]
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
[]
> @@ -1109,6 +1109,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>  			ret = -EFAULT;
>  		break;
>  	case FBIOGET_FSCREENINFO:
> +		memset(&fix, 0, sizeof(fix));
>  		lock_fb_info(info);
>  		fix = info->fix;
>  		if (info->flags & FBINFO_HIDE_SMEM_START)

Perhaps better to change the struct copy to a 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 e6a1c80..364699 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1110,7 +1110,7 @@ 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);




WARNING: multiple messages have this Message-ID (diff)
From: Joe Perches <joe@perches.com>
To: Dan Carpenter <dan.carpenter@oracle.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Andrea Righi <righi.andrea@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	Sam Ravnborg <sam@ravnborg.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Peter Rosin <peda@axentia.se>, 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,
	security@kernel.org, Kees Cook <keescook@chromium.org>,
	Julia Lawall <Julia.Lawall@lip6.fr>
Subject: Re: [PATCH] fbdev: potential information leak in do_fb_ioctl()
Date: Tue, 29 Oct 2019 18:35:55 +0000	[thread overview]
Message-ID: <5a6f05cef45dbb4f77008b36d7a63b429f1519ec.camel@perches.com> (raw)
In-Reply-To: <20191029182320.GA17569@mwanda>

On Tue, 2019-10-29 at 21:23 +0300, Dan Carpenter wrote:
> 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.
[]
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
[]
> @@ -1109,6 +1109,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>  			ret = -EFAULT;
>  		break;
>  	case FBIOGET_FSCREENINFO:
> +		memset(&fix, 0, sizeof(fix));
>  		lock_fb_info(info);
>  		fix = info->fix;
>  		if (info->flags & FBINFO_HIDE_SMEM_START)

Perhaps better to change the struct copy to a 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 e6a1c80..364699 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1110,7 +1110,7 @@ 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);

WARNING: multiple messages have this Message-ID (diff)
From: Joe Perches <joe@perches.com>
To: Dan Carpenter <dan.carpenter@oracle.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Andrea Righi <righi.andrea@gmail.com>
Cc: linux-fbdev@vger.kernel.org, security@kernel.org,
	Kees Cook <keescook@chromium.org>,
	kernel-janitors@vger.kernel.org,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Julia Lawall <Julia.Lawall@lip6.fr>,
	Gerd Hoffmann <kraxel@redhat.com>,
	Sam Ravnborg <sam@ravnborg.org>, Peter Rosin <peda@axentia.se>
Subject: Re: [PATCH] fbdev: potential information leak in do_fb_ioctl()
Date: Tue, 29 Oct 2019 11:35:55 -0700	[thread overview]
Message-ID: <5a6f05cef45dbb4f77008b36d7a63b429f1519ec.camel@perches.com> (raw)
Message-ID: <20191029183555.Zr60zsgbyIy50ApWjjTrnbftlfg2r7PMp78HpUDv3Jw@z> (raw)
In-Reply-To: <20191029182320.GA17569@mwanda>

On Tue, 2019-10-29 at 21:23 +0300, Dan Carpenter wrote:
> 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.
[]
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
[]
> @@ -1109,6 +1109,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>  			ret = -EFAULT;
>  		break;
>  	case FBIOGET_FSCREENINFO:
> +		memset(&fix, 0, sizeof(fix));
>  		lock_fb_info(info);
>  		fix = info->fix;
>  		if (info->flags & FBINFO_HIDE_SMEM_START)

Perhaps better to change the struct copy to a 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 e6a1c80..364699 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1110,7 +1110,7 @@ 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);



_______________________________________________
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dri-devel@lists.freedesktop.org
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  reply	other threads:[~2019-10-29 18:36 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 [this message]
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     ` [PATCH v2] " Dan Carpenter
2020-01-13 11:08       ` 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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