From: Dongliang Mu <mudongliangabcd@gmail.com>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Dongliang Mu <mudongliangabcd@gmail.com>,
George Kennedy <george.kennedy@oracle.com>,
syzbot+e5fd3e65515b48c02a30@syzkaller.appspotmail.com,
Dan Carpenter <dan.carpenter@oracle.com>,
Dhaval Giani <dhaval.giani@oracle.com>,
Sasha Levin <sashal@kernel.org>,
dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 4.19] fbmem: add margin check to fb_check_caps()
Date: Thu, 2 Sep 2021 14:02:08 +0800 [thread overview]
Message-ID: <20210902060213.1702544-1-mudongliangabcd@gmail.com> (raw)
[ 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.
Note that, this patch needs special handling to backport it to linux
kernel 4.19, 4.14, 4.9, 4.4.
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 84845275dbef..de04c097d67c 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -991,6 +991,10 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
goto done;
}
+ /* 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 reply other threads:[~2021-09-02 6:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-02 6:02 Dongliang Mu [this message]
2021-09-02 6:05 ` [PATCH 4.19] fbmem: add margin check to fb_check_caps() Dongliang Mu
2021-09-02 13:15 ` Geert Uytterhoeven
2021-09-03 1:09 ` Dongliang Mu
2021-09-02 6:10 Dongliang Mu
2021-09-03 13:55 ` Greg KH
2021-09-04 2:12 ` Dongliang Mu
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