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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next prev parent reply other threads:[~2019-10-29 18:36 UTC|newest]
Thread overview: 21+ 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 18:35 ` Joe Perches [this message]
2019-10-29 18:35 ` Joe Perches
2019-10-29 19:02 ` Eric W. Biederman
2019-10-29 19:02 ` Eric W. Biederman
2019-10-30 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 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 22:12 ` Eric W. Biederman
2019-10-31 22:12 ` Eric W. Biederman
2020-01-03 13:07 ` Bartlomiej Zolnierkiewicz
2020-01-13 11:08 ` [PATCH v2] " Dan Carpenter
2020-01-15 14:31 ` Bartlomiej Zolnierkiewicz
2020-01-13 12:49 ` [PATCH] " Arnd Bergmann
2020-01-15 13:09 ` Bartlomiej Zolnierkiewicz
2020-01-15 13:16 ` Arnd Bergmann
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