From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Masayuki Ohtake <masa-korg-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
Cc: andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
joel.clark-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, "Wang,
Yong Y" <yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
qi.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Ben Dooks (embedded platforms)"
<ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>,
"Jean Delvare (PC drivers,
core)" <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
Subject: Re: [PATCH] I2C driver of Topcliff PCH
Date: Tue, 20 Jul 2010 11:29:52 +0200 [thread overview]
Message-ID: <201007201129.53110.arnd@arndb.de> (raw)
In-Reply-To: <000601cb27e4$3768c170$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
On Tuesday 20 July 2010, Masayuki Ohtake wrote:
> > > @@ -147,6 +148,11 @@ static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
> > > if (tmp == NULL)
> > > return -ENOMEM;
> > >
> > > + if (copy_from_user(tmp, buf, count)) {
> > > + kfree(tmp);
> > > + return -EFAULT;
> > > + }
> > > +
> > > pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
> > > iminor(file->f_path.dentry->d_inode), count);
> >
> >
> > A read function should not do copy_from_user, only copy_to_user.
> > If you are worried about returning invalid data from kernel space,
> > better use kzalloc instead of kmalloc to get the buffer.
>
> Our I2C HW has special mode.
> To control the mode, our i2c driver has copy_from_user.
That is a highly unusual interface and I would definitely not recommend doing
this. Please use an ioctl operation for anything that has both input and output
data.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: "Masayuki Ohtake" <masa-korg@dsn.okisemi.com>
Cc: andrew.chih.howe.khor@intel.com, joel.clark@intel.com, "Wang,
Yong Y" <yong.y.wang@intel.com>,
qi.wang@intel.com, "LKML" <linux-kernel@vger.kernel.org>,
linux-i2c@vger.kernel.org,
"Ben Dooks \(embedded platforms\)" <ben-linux@fluff.org>,
"Jean Delvare \(PC drivers, core\)" <khali@linux-fr.org>
Subject: Re: [PATCH] I2C driver of Topcliff PCH
Date: Tue, 20 Jul 2010 11:29:52 +0200 [thread overview]
Message-ID: <201007201129.53110.arnd@arndb.de> (raw)
In-Reply-To: <000601cb27e4$3768c170$66f8800a@maildom.okisemi.com>
On Tuesday 20 July 2010, Masayuki Ohtake wrote:
> > > @@ -147,6 +148,11 @@ static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
> > > if (tmp == NULL)
> > > return -ENOMEM;
> > >
> > > + if (copy_from_user(tmp, buf, count)) {
> > > + kfree(tmp);
> > > + return -EFAULT;
> > > + }
> > > +
> > > pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
> > > iminor(file->f_path.dentry->d_inode), count);
> >
> >
> > A read function should not do copy_from_user, only copy_to_user.
> > If you are worried about returning invalid data from kernel space,
> > better use kzalloc instead of kmalloc to get the buffer.
>
> Our I2C HW has special mode.
> To control the mode, our i2c driver has copy_from_user.
That is a highly unusual interface and I would definitely not recommend doing
this. Please use an ioctl operation for anything that has both input and output
data.
Arnd
next prev parent reply other threads:[~2010-07-20 9:29 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-22 5:33 [PATCH] Topcliff PHUB: Generate PacketHub driver Masayuki Ohtak
2010-06-22 10:33 ` Masayuki Ohtak
2010-06-22 22:12 ` Andrew Morton
2010-06-23 0:31 ` Masayuki Ohtake
2010-06-22 11:30 ` Arnd Bergmann
2010-06-22 13:52 ` Yong Wang
2010-06-29 23:31 ` Andy Isaacson
2010-06-30 5:58 ` Masayuki Ohtake
2010-06-30 18:28 ` Andy Isaacson
2010-07-01 4:08 ` Masayuki Ohtake
2010-06-30 7:51 ` [PATCH] Packet hub driver of Topcliff PCH Masayuki Ohtak
2010-06-30 18:05 ` Randy Dunlap
2010-07-01 2:52 ` Masayuki Ohtake
2010-07-01 5:14 ` Masayuki Ohtak
2010-07-01 6:58 ` Andy Isaacson
2010-07-01 10:13 ` Masayuki Ohtake
2010-07-01 10:38 ` Masayuki Ohtak
2010-07-01 15:44 ` Randy Dunlap
2010-07-05 7:20 ` Masayuki Ohtak
2010-07-05 15:04 ` Arnd Bergmann
2010-07-06 15:58 ` Randy Dunlap
2010-07-06 6:20 ` Masayuki Ohtak
2010-07-06 6:30 ` Arnd Bergmann
2010-07-07 1:19 ` Yong Wang
2010-07-09 20:00 ` Andrew Morton
2010-07-12 1:25 ` Masayuki Ohtake
2010-07-15 7:25 ` Masayuki Ohtak
2010-07-15 7:42 ` [PATCH] I2C " Masayuki Ohtak
[not found] ` <4C3EBBEC.9020304-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
2010-07-15 19:35 ` Arnd Bergmann
2010-07-15 19:35 ` Arnd Bergmann
2010-07-20 0:05 ` Masayuki Ohtake
2010-07-20 0:05 ` Masayuki Ohtake
2010-07-20 4:55 ` Masayuki Ohtake
2010-07-20 4:55 ` Masayuki Ohtake
[not found] ` <000401cb27c7$ce732960$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-07-20 9:27 ` Arnd Bergmann
2010-07-20 9:27 ` Arnd Bergmann
2010-07-20 12:38 ` Masayuki Ohtake
2010-07-20 12:38 ` Masayuki Ohtake
2010-07-20 8:19 ` Masayuki Ohtake
2010-07-20 8:19 ` Masayuki Ohtake
[not found] ` <000601cb27e4$3768c170$66f8800a-a06+6cuVnkTSQfdrb5gaxUEOCMrvLtNR@public.gmane.org>
2010-07-20 9:29 ` Arnd Bergmann [this message]
2010-07-20 9:29 ` Arnd Bergmann
2010-07-20 12:40 ` Masayuki Ohtake
2010-07-20 12:40 ` Masayuki Ohtake
[not found] ` <4C204B0D.2030201-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
2010-07-21 6:46 ` Masayuki Ohtak
2010-07-21 6:46 ` Masayuki Ohtak
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=201007201129.53110.arnd@arndb.de \
--to=arnd-r2ngtmty4d4@public.gmane.org \
--cc=andrew.chih.howe.khor-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
--cc=ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org \
--cc=joel.clark-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
--cc=khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org \
--cc=linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=masa-korg-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org \
--cc=qi.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
--cc=yong.y.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.