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In-Reply-To: <201012211925.38201.arnd@arndb.de>
References: <d21ad74592c295d59f5806f30a053745b5765397.1292894256.git.tfransosi@gmail.com>
	<201012211925.38201.arnd@arndb.de>
Date: Tue, 21 Dec 2010 16:34:04 -0200
Message-ID: <AANLkTikbvST_B+4x3Xt=gxFhM1TBOrXVc1HjZT3zTXrt@mail.gmail.com>
Subject: Re: [PATCH] drivers/media/video/v4l2-compat-ioctl32.c: Check the
 return value of copy_to_user
From: Thiago Farina <tfransosi@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-kernel@vger.kernel.org,
        Guennadi Liakhovetski <g.liakhovetski@gmx.de>,
        Mauro Carvalho Chehab <mchehab@infradead.org>,
        linux-media@vger.kernel.org
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On Tue, Dec 21, 2010 at 4:25 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Tuesday 21 December 2010 02:18:06 Thiago Farina wrote:
>> diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
>> index e30e8df..55825ec 100644
>> --- a/drivers/media/video/v4l2-compat-ioctl32.c
>> +++ b/drivers/media/video/v4l2-compat-ioctl32.c
>> @@ -206,7 +206,9 @@ static struct video_code __user *get_microcode32(struct video_code32 *kp)
>>          * user address is invalid, the native ioctl will do
>>          * the error handling for us
>>          */
>> -       (void) copy_to_user(up->loadwhat, kp->loadwhat, sizeof(up->loadwhat));
>> +       if (copy_to_user(up->loadwhat, kp->loadwhat, sizeof(up->loadwhat)))
>> +               return NULL;
>> +
>>         (void) put_user(kp->datasize, &up->datasize);
>>         (void) put_user(compat_ptr(kp->data), &up->data);
>>         return up;
>
> Did you read the comment above the code you changed?
>
Yes, I read, but I went ahead.

> You can probably change this function to look at the return code of
> copy_to_user, but then you need to treat the put_user return code
> the same, and change the comment.
>

Right, I will do the same with put_user, but I'm afraid of changing the comment.
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