linux-fbdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Zheyu Ma <zheyuma97@gmail.com>
To: adaplas@gmail.com
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, Zheyu Ma <zheyuma97@gmail.com>
Subject: [PATCH v2 2/3] video: fbdev: kyro: Error out if 'pixclock' equals zero
Date: Mon, 26 Jul 2021 10:03:54 +0000	[thread overview]
Message-ID: <1627293835-17441-3-git-send-email-zheyuma97@gmail.com> (raw)
In-Reply-To: <1627293835-17441-1-git-send-email-zheyuma97@gmail.com>

The userspace program could pass any values to the driver through
ioctl() interface. if the driver doesn't check the value of 'pixclock',
it may cause divide error because the value of 'lineclock' and
'frameclock' will be zero.

Fix this by checking whether 'pixclock' is zero in kyrofb_check_var().

The following log reveals it:

[  103.073930] divide error: 0000 [#1] PREEMPT SMP KASAN PTI
[  103.073942] CPU: 4 PID: 12483 Comm: syz-executor Not tainted 5.14.0-rc2-00478-g2734d6c1b1a0-dirty #118
[  103.073959] RIP: 0010:kyrofb_set_par+0x316/0xc80
[  103.074045] Call Trace:
[  103.074048]  ? ___might_sleep+0x1ee/0x2d0
[  103.074060]  ? kyrofb_ioctl+0x330/0x330
[  103.074069]  fb_set_var+0x5bf/0xeb0
[  103.074078]  ? fb_blank+0x1a0/0x1a0
[  103.074085]  ? lock_acquire+0x3bd/0x530
[  103.074094]  ? lock_release+0x810/0x810
[  103.074103]  ? ___might_sleep+0x1ee/0x2d0
[  103.074114]  ? __mutex_lock+0x620/0x1190
[  103.074126]  ? trace_hardirqs_on+0x6a/0x1c0
[  103.074137]  do_fb_ioctl+0x31e/0x700
[  103.074144]  ? fb_getput_cmap+0x280/0x280
[  103.074152]  ? rcu_read_lock_sched_held+0x11/0x80
[  103.074162]  ? rcu_read_lock_sched_held+0x11/0x80
[  103.074171]  ? __sanitizer_cov_trace_switch+0x67/0xf0
[  103.074181]  ? __sanitizer_cov_trace_const_cmp2+0x20/0x80
[  103.074191]  ? do_vfs_ioctl+0x14b/0x16c0
[  103.074199]  ? vfs_fileattr_set+0xb60/0xb60
[  103.074207]  ? rcu_read_lock_sched_held+0x11/0x80
[  103.074216]  ? lock_release+0x483/0x810
[  103.074224]  ? __fget_files+0x217/0x3d0
[  103.074234]  ? __fget_files+0x239/0x3d0
[  103.074243]  ? do_fb_ioctl+0x700/0x700
[  103.074250]  fb_ioctl+0xe6/0x130

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
Changes in v2:
    - Make commmit log more descriptive
---
 drivers/video/fbdev/kyro/fbdev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/video/fbdev/kyro/fbdev.c b/drivers/video/fbdev/kyro/fbdev.c
index 8fbde92ae8b9..6db7e5e83f11 100644
--- a/drivers/video/fbdev/kyro/fbdev.c
+++ b/drivers/video/fbdev/kyro/fbdev.c
@@ -394,6 +394,9 @@ static int kyrofb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 {
 	struct kyrofb_info *par = info->par;
 
+	if (!var->pixclock)
+		return -EINVAL;
+
 	if (var->bits_per_pixel != 16 && var->bits_per_pixel != 32) {
 		printk(KERN_WARNING "kyrofb: depth not supported: %u\n", var->bits_per_pixel);
 		return -EINVAL;
-- 
2.17.6


  parent reply	other threads:[~2021-07-26 10:04 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26 10:03 [PATCH v2 0/3] " Zheyu Ma
2021-07-26 10:03 ` [PATCH v2 1/3] video: fbdev: asiliantfb: " Zheyu Ma
2021-09-10 15:16   ` Geert Uytterhoeven
2021-07-26 10:03 ` Zheyu Ma [this message]
2021-07-26 10:03 ` [PATCH v2 3/3] video: fbdev: riva: " Zheyu Ma

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=1627293835-17441-3-git-send-email-zheyuma97@gmail.com \
    --to=zheyuma97@gmail.com \
    --cc=adaplas@gmail.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --subject='Re: [PATCH v2 2/3] video: fbdev: kyro: Error out if '\''pixclock'\'' equals zero' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).