From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Wei Chen <harperchen1110@gmail.com>, Helge Deller <deller@gmx.de>,
Sasha Levin <sashal@kernel.org>,
javierm@redhat.com, tzimmermann@suse.de,
wsa+renesas@sang-engineering.com, linux-fbdev@vger.kernel.org,
dri-devel@lists.freedesktop.org
Subject: [PATCH AUTOSEL 4.14 4/9] fbdev: tgafb: Fix potential divide by zero
Date: Wed, 22 Mar 2023 16:03:31 -0400 [thread overview]
Message-ID: <20230322200337.1997810-4-sashal@kernel.org> (raw)
In-Reply-To: <20230322200337.1997810-1-sashal@kernel.org>
From: Wei Chen <harperchen1110@gmail.com>
[ Upstream commit f90bd245de82c095187d8c2cabb8b488a39eaecc ]
fb_set_var would by called when user invokes ioctl with cmd
FBIOPUT_VSCREENINFO. User-provided data would finally reach
tgafb_check_var. In case var->pixclock is assigned to zero,
divide by zero would occur when checking whether reciprocal
of var->pixclock is too high.
Similar crashes have happened in other fbdev drivers. There
is no check and modification on var->pixclock along the call
chain to tgafb_check_var. We believe it could also be triggered
in driver tgafb from user site.
Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/video/fbdev/tgafb.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/video/fbdev/tgafb.c b/drivers/video/fbdev/tgafb.c
index 65ba9921506e2..9d2912947eef6 100644
--- a/drivers/video/fbdev/tgafb.c
+++ b/drivers/video/fbdev/tgafb.c
@@ -166,6 +166,9 @@ tgafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
struct tga_par *par = (struct tga_par *)info->par;
+ if (!var->pixclock)
+ return -EINVAL;
+
if (par->tga_type == TGA_TYPE_8PLANE) {
if (var->bits_per_pixel != 8)
return -EINVAL;
--
2.39.2
next parent reply other threads:[~2023-03-22 20:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230322200337.1997810-1-sashal@kernel.org>
2023-03-22 20:03 ` Sasha Levin [this message]
2023-03-22 20:03 ` [PATCH AUTOSEL 4.14 6/9] fbdev: nvidia: Fix potential divide by zero Sasha Levin
2023-03-22 20:03 ` [PATCH AUTOSEL 4.14 7/9] fbdev: intelfb: " Sasha Levin
2023-03-22 20:03 ` [PATCH AUTOSEL 4.14 8/9] fbdev: lxfb: " Sasha Levin
2023-03-22 20:03 ` [PATCH AUTOSEL 4.14 9/9] fbdev: au1200fb: " Sasha Levin
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