From: Dan Rosenberg <drosenberg@vsecurity.com>
To: thomas@winischhofer.net
Cc: linux-kernel@vger.kernel.org, security@kernel.org, stable@kernel.org
Subject: [PATCH] drivers/video/sis/sis_main.c: prevent reading uninitialized stack memory
Date: Wed, 15 Sep 2010 17:43:53 -0400 [thread overview]
Message-ID: <1284587033.6275.96.camel@dan> (raw)
The FBIOGET_VBLANK device ioctl allows unprivileged users to read 16
bytes of uninitialized stack memory, because the "reserved" member of
the fb_vblank struct declared on the stack is not altered or zeroed
before being copied back to the user. This patch takes care of it.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
--- linux-2.6.35.4.orig/drivers/video/sis/sis_main.c 2010-08-26 19:47:12.000000000 -0400
+++ linux-2.6.35.4/drivers/video/sis/sis_main.c 2010-09-15 11:52:41.437375730 -0400
@@ -1701,6 +1701,9 @@ static int sisfb_ioctl(struct fb_info *i
break;
case FBIOGET_VBLANK:
+
+ memset(&sisvbblank, 0, sizeof(struct fb_vblank));
+
sisvbblank.count = 0;
sisvbblank.flags = sisfb_setupvbblankflags(ivideo, &sisvbblank.vcount, &sisvbblank.hcount);
next reply other threads:[~2010-09-15 21:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-15 21:43 Dan Rosenberg [this message]
2010-09-16 21:06 ` [Security] [PATCH] drivers/video/sis/sis_main.c: prevent reading uninitialized stack memory Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1284587033.6275.96.camel@dan \
--to=drosenberg@vsecurity.com \
--cc=linux-kernel@vger.kernel.org \
--cc=security@kernel.org \
--cc=stable@kernel.org \
--cc=thomas@winischhofer.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox