From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Zheyu Ma <zheyuma97@gmail.com>
Cc: Helge Deller <deller@gmx.de>,
Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
DRI Development <dri-devel@lists.freedesktop.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/7] video: fbdev: arkfb: Error out if 'pixclock' equals zero
Date: Mon, 4 Apr 2022 17:52:05 +0200 [thread overview]
Message-ID: <CAMuHMdW4ynAyE9sey17f1iP_0nSJexWOB+nYdfRFXPbQXfCksA@mail.gmail.com> (raw)
In-Reply-To: <20220404084723.79089-7-zheyuma97@gmail.com>
On Mon, Apr 4, 2022 at 3:10 PM Zheyu Ma <zheyuma97@gmail.com> wrote:
> 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.
>
> Fix this by checking whether 'pixclock' is zero.
>
> The following log reveals it:
>
> [ 76.603696] divide error: 0000 [#1] PREEMPT SMP KASAN PTI
> [ 76.603712] RIP: 0010:arkfb_set_par+0x10fc/0x24f0
> [ 76.603762] Call Trace:
> [ 76.603764] <TASK>
> [ 76.603773] fb_set_var+0x604/0xeb0
> [ 76.603827] do_fb_ioctl+0x234/0x670
> [ 76.603873] fb_ioctl+0xdd/0x130
> [ 76.603881] do_syscall_64+0x3b/0x90
>
> Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Thanks for your patch!
> --- a/drivers/video/fbdev/arkfb.c
> +++ b/drivers/video/fbdev/arkfb.c
> @@ -566,6 +566,9 @@ static int arkfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
> {
> int rv, mem, step;
>
> + if (!var->pixclock)
> + return -EINVAL;
When passed an invalid value, .check_var() is supposed to
round up the invalid to a valid value, if possible.
> +
> /* Find appropriate format */
> rv = svga_match_format (arkfb_formats, var, NULL);
> if (rv < 0)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2022-04-04 15:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-04 8:47 [PATCH 0/7] Fix divide errors in fbdev drivers Zheyu Ma
2022-04-04 8:47 ` [PATCH 1/7] video: fbdev: i740fb: Error out if 'pixclock' equals zero Zheyu Ma
2022-04-07 19:49 ` Helge Deller
2022-04-08 1:58 ` Zheyu Ma
2022-04-10 9:02 ` Ondrej Zary
2022-04-11 6:18 ` Helge Deller
2022-04-04 8:47 ` [PATCH 2/7] video: fbdev: neofb: Fix the check of 'var->pixclock' Zheyu Ma
2022-04-04 8:47 ` [PATCH 3/7] video: fbdev: kyro: Error out if 'lineclock' equals zero Zheyu Ma
2022-04-04 8:47 ` [PATCH 4/7] video: fbdev: vt8623fb: Error out if 'pixclock' " Zheyu Ma
2022-04-04 11:47 ` Geert Uytterhoeven
2022-04-04 8:47 ` [PATCH 5/7] video: fbdev: tridentfb: " Zheyu Ma
2022-04-04 8:47 ` [PATCH 6/7] video: fbdev: arkfb: " Zheyu Ma
2022-04-04 15:52 ` Geert Uytterhoeven [this message]
2022-04-04 8:47 ` [PATCH 7/7] video: fbdev: s3fb: " Zheyu Ma
2022-04-04 15:52 ` Geert Uytterhoeven
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=CAMuHMdW4ynAyE9sey17f1iP_0nSJexWOB+nYdfRFXPbQXfCksA@mail.gmail.com \
--to=geert@linux-m68k.org \
--cc=deller@gmx.de \
--cc=dri-devel@lists.freedesktop.org \
--cc=linux-fbdev@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=zheyuma97@gmail.com \
/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;
as well as URLs for NNTP newsgroup(s).