LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Johan Hovold <johan@kernel.org>
To: YueHaibing <yuehaibing@huawei.com>
Cc: jacmet@sunsite.dk, gregkh@linuxfoundation.org, jslaby@suse.com,
	shubhrajyoti.datta@xilinx.com, linux-kernel@vger.kernel.org,
	linux-serial@vger.kernel.org
Subject: Re: [PATCH] serial-uartlite: Fix null-ptr-deref in ulite_exit
Date: Fri, 17 May 2019 09:55:02 +0200	[thread overview]
Message-ID: <20190517075502.GE28564@localhost> (raw)
In-Reply-To: <20190516040931.16276-1-yuehaibing@huawei.com>

On Thu, May 16, 2019 at 12:09:31PM +0800, YueHaibing wrote:
> If ulite_probe is not called or failed to registed
> uart_register_driver, unload the module will call
> uart_unregister_driver, which will tigger NULL
> pointer dereference like this:
> 
> BUG: KASAN: null-ptr-deref in tty_unregister_driver+0x19/0x100
> Read of size 4 at addr 0000000000000034 by task syz-executor.0/4246

> This patch fix this by moving uart_unregister_driver
> to ulite_remove.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Fixes: 415b43bdb008 ("tty: serial: uartlite: Move uart register to probe")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> ---
>  drivers/tty/serial/uartlite.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
> index b8b912b..2e49fb6 100644
> --- a/drivers/tty/serial/uartlite.c
> +++ b/drivers/tty/serial/uartlite.c
> @@ -867,6 +867,7 @@ static int ulite_remove(struct platform_device *pdev)
>  	pm_runtime_disable(&pdev->dev);
>  	pm_runtime_set_suspended(&pdev->dev);
>  	pm_runtime_dont_use_autosuspend(&pdev->dev);
> +	uart_unregister_driver(&ulite_uart_driver);

This broken. Consider what happens if you have tho ports registered and
you unbind the first.

Someone else sent a fix for this here

	https://lkml.kernel.org/r/20190514033219.169947-1-wangkefeng.wang@huawei.com

That fix also has some issues, but is still better given the current
state this driver is in.

>  	return rc;
>  }
>  
> @@ -897,7 +898,6 @@ static int __init ulite_init(void)
>  static void __exit ulite_exit(void)
>  {
>  	platform_driver_unregister(&ulite_platform_driver);
> -	uart_unregister_driver(&ulite_uart_driver);
>  }
>  
>  module_init(ulite_init);

Johan

  parent reply	other threads:[~2019-05-17  7:55 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-16  4:09 YueHaibing
2019-05-16 14:52 ` Shubhrajyoti Datta
2019-05-17  7:55 ` Johan Hovold [this message]
2019-05-21 10:10   ` Greg KH
2019-05-23  9:18     ` Johan Hovold
2019-05-23 10:46       ` Michal Simek
2019-05-23 12:31         ` Johan Hovold
2019-05-23 12:47           ` Michal Simek

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=20190517075502.GE28564@localhost \
    --to=johan@kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=jacmet@sunsite.dk \
    --cc=jslaby@suse.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-serial@vger.kernel.org \
    --cc=shubhrajyoti.datta@xilinx.com \
    --cc=yuehaibing@huawei.com \
    --subject='Re: [PATCH] serial-uartlite: Fix null-ptr-deref in ulite_exit' \
    /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).