From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Vladimir Motyka <vladimir.motyka@gmail.com>
Cc: Julia Lawall <julia@diku.dk>,
cjb@laptop.org, kernel-janitors@vger.kernel.org,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drivers/mmc/card/block.c: fix potential null dereference 'idata'
Date: Mon, 9 May 2011 18:13:55 +0300 [thread overview]
Message-ID: <BANLkTimOfmS=tKMY7Z_vRcCWEO6drgwegQ@mail.gmail.com> (raw)
In-Reply-To: <4DC802C0.9040302@gmail.com>
On Mon, May 9, 2011 at 6:05 PM, Vladimir Motyka
<vladimir.motyka@gmail.com> wrote:
> On 05/09/2011 04:32 PM, Julia Lawall wrote:
>> On Mon, 9 May 2011, Vladimir Motyka wrote:
>>
>>> When allocation of idata fails there was a null dereferece.
>>
>> Why not have a different label for the two cases? That would make the
>> code easier to statically analyze, and perhaps be more understandable as
>> well.
>>
>> julia
>>
> I think You are right. So it could be better like this?
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 3dec493..a03cdc6 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -237,7 +237,7 @@ static struct mmc_blk_ioc_data
> *mmc_blk_ioctl_copy_from_user(
> idata = kzalloc(sizeof(*idata), GFP_KERNEL);
> if (!idata) {
> err = -ENOMEM;
> - goto copy_err;
> + goto alloc_err;
> }
>
> if (copy_from_user(&idata->ic, user, sizeof(idata->ic))) {
> @@ -266,9 +266,9 @@ static struct mmc_blk_ioc_data
> *mmc_blk_ioctl_copy_from_user(
> return idata;
>
> copy_err:
> - if(idata)
> - kfree(idata->buf);
> + kfree(idata->buf);
Make it one patch not series.
> kfree(idata);
> +alloc_err:
> return ERR_PTR(err);
> }
>
> Or it could return right after allocation fails so there needn't be
> goto. It is simplier, but maybe worse looking and to read. What is your
> opinion?
>
> Vladimir Motyka
>
>>
>>> Signed-off-by: Vladimir Motyka <vladimir.motyka@gmail.com>
>>>
>>> ---
>>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>>> index 407836d..3dec493 100644
>>> --- a/drivers/mmc/card/block.c
>>> +++ b/drivers/mmc/card/block.c
>>> @@ -266,10 +266,10 @@ static struct mmc_blk_ioc_data
>>> *mmc_blk_ioctl_copy_from_user(
>>> return idata;
>>>
>>> copy_err:
>>> - kfree(idata->buf);
>>> + if(idata)
>>> + kfree(idata->buf);
>>> kfree(idata);
>>> return ERR_PTR(err);
>>> -
>>> }
>>>
>>> static int mmc_blk_ioctl_cmd(struct block_device *bdev,
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2011-05-09 15:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-09 14:05 [PATCH] drivers/mmc/card/block.c: fix potential null dereference 'idata' Vladimir Motyka
2011-05-09 14:32 ` Julia Lawall
2011-05-09 15:05 ` Vladimir Motyka
2011-05-09 15:13 ` Andy Shevchenko [this message]
2011-05-09 15:14 ` Julia Lawall
2011-05-09 16:08 ` Vladimir Motyka
2011-05-09 16:12 ` Julia Lawall
2011-05-09 20:37 ` Vladimir Motyka
2011-05-09 20:37 ` Vladimir Motyka
2011-05-11 4:03 ` Chris Ball
2011-05-10 7:47 ` Andy Shevchenko
2011-05-10 7:57 ` Julia Lawall
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='BANLkTimOfmS=tKMY7Z_vRcCWEO6drgwegQ@mail.gmail.com' \
--to=andy.shevchenko@gmail.com \
--cc=cjb@laptop.org \
--cc=julia@diku.dk \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mmc@vger.kernel.org \
--cc=vladimir.motyka@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).