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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Marcelo Diop-Gonzalez <marcgonzalez@google.com>
Cc: devel@driverdev.osuosl.org, gregkh@linuxfoundation.org,
	linux-rpi-kernel@lists.infradead.org, wahrenst@gmx.net,
	eric@anholt.net
Subject: Re: [PATCH 3/3] staging: vchiq: Have vchiq_dump_* functions return an error code
Date: Wed, 20 Nov 2019 21:50:47 +0300
Message-ID: <20191120185047.GE5604@kadam> (raw)
In-Reply-To: <b4b5b1c7ec61a25fb3ca3c90687dc80db8a21e90.1574253964.git.marcgonzalez@google.com>

Thanks for the patch.  Looks good.

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>

On Wed, Nov 20, 2019 at 10:36:48AM -0500, Marcelo Diop-Gonzalez wrote:
>  	copy_bytes = min_t(int, len, context->space - context->actual);
>  	if (copy_bytes == 0)
> -		return;
> +		return 0;
>  	if (copy_to_user(context->buf + context->actual, str,
>  			 copy_bytes))
> -		context->actual = -EFAULT;
                ^^^^^^^^^^^^^^^^^^^^^^^^^

> +		return -EFAULT;
>  	context->actual += copy_bytes;
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In the original code we saved the error code to context->actual, then
we added some bytes

>  	len -= copy_bytes;
>  
> @@ -2109,8 +2108,9 @@ vchiq_dump(void *dump_context, const char *str, int len)
>  
>  		if (copy_to_user(context->buf + context->actual - 1,
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
and then we tried to use the result to corrupt the user space program.
So this patch is a nice bug fix.

>  				 &cr, 1))
> -			context->actual = -EFAULT;
> +			return -EFAULT;
>  	}
> +	return 0;
>  }

regards,
dan carpenter
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Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-20 15:36 [PATCH 0/3] staging: vchiq: Fix vchiq_read return value in case of error Marcelo Diop-Gonzalez
2019-11-20 15:36 ` [PATCH 1/3] staging: vchiq_dump: Replace min with min_t Marcelo Diop-Gonzalez
2019-11-20 15:46   ` Greg KH
2019-11-20 15:36 ` [PATCH 2/3] staging: vchiq: Refactor indentation in vchiq_dump_* functions Marcelo Diop-Gonzalez
2019-11-20 15:36 ` [PATCH 3/3] staging: vchiq: Have vchiq_dump_* functions return an error code Marcelo Diop-Gonzalez
2019-11-20 18:50   ` Dan Carpenter [this message]
2019-11-21 21:25     ` Marcelo Diop-Gonzalez
2019-11-20 20:20 ` [PATCH v2 0/4] staging: vchiq: Fix vchiq_read return value in case of error Marcelo Diop-Gonzalez
2019-11-20 20:20   ` [PATCH v2 1/4] staging: vchiq: Fix block comment format in vchiq_dump() Marcelo Diop-Gonzalez
2019-11-20 20:21   ` [PATCH v2 2/4] staging: vchiq_dump: Replace min with min_t Marcelo Diop-Gonzalez
2019-11-20 20:21   ` [PATCH v2 3/4] staging: vchiq: Refactor indentation in vchiq_dump_* functions Marcelo Diop-Gonzalez
2019-11-20 20:21   ` [PATCH v2 4/4] staging: vchiq: Have vchiq_dump_* functions return an error code Marcelo Diop-Gonzalez
2019-11-21 19:38   ` [PATCH v2 0/4] staging: vchiq: Fix vchiq_read return value in case of error Nicolas Saenz Julienne
2019-11-21 21:24     ` Marcelo Diop-Gonzalez
2019-11-21 10:42 ` [PATCH 0/3] " Stefan Wahren
2019-11-21 19:41   ` Nicolas Saenz Julienne

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