From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: George Kennedy <george.kennedy@oracle.com>,
syzbot+e5fd3e65515b48c02a30@syzkaller.appspotmail.com,
Dan Carpenter <dan.carpenter@oracle.com>,
Dhaval Giani <dhaval.giani@oracle.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Sasha Levin <sashal@kernel.org>,
linux-fbdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 65/80] fbmem: add margin check to fb_check_caps()
Date: Sun, 18 Oct 2020 15:22:16 -0400 [thread overview]
Message-ID: <20201018192231.4054535-65-sashal@kernel.org> (raw)
Message-ID: <20201018192216.EgsrDfY6czuKQkbfF8RwGd_otNJpO9XTKfLDRD_14Wk@z> (raw)
In-Reply-To: <20201018192231.4054535-1-sashal@kernel.org>
From: George Kennedy <george.kennedy@oracle.com>
[ Upstream commit a49145acfb975d921464b84fe00279f99827d816 ]
A fb_ioctl() FBIOPUT_VSCREENINFO call with invalid xres setting
or yres setting in struct fb_var_screeninfo will result in a
KASAN: vmalloc-out-of-bounds failure in bitfill_aligned() as
the margins are being cleared. The margins are cleared in
chunks and if the xres setting or yres setting is a value of
zero upto the chunk size, the failure will occur.
Add a margin check to validate xres and yres settings.
Signed-off-by: George Kennedy <george.kennedy@oracle.com>
Reported-by: syzbot+e5fd3e65515b48c02a30@syzkaller.appspotmail.com
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Dhaval Giani <dhaval.giani@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1594149963-13801-1-git-send-email-george.kennedy@oracle.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/video/fbdev/core/fbmem.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 97abcd497c7e0..bf76dadbed87f 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1001,6 +1001,10 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
return 0;
}
+ /* bitfill_aligned() assumes that it's at least 8x8 */
+ if (var->xres < 8 || var->yres < 8)
+ return -EINVAL;
+
ret = info->fbops->fb_check_var(var, info);
if (ret)
--
2.25.1
next parent reply other threads:[~2020-10-18 19:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20201018192231.4054535-1-sashal@kernel.org>
2020-10-18 19:22 ` Sasha Levin [this message]
2020-10-18 19:22 ` [PATCH AUTOSEL 5.4 65/80] fbmem: add margin check to fb_check_caps() Sasha Levin
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