Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932151AbWEGNDc (ORCPT ); Sun, 7 May 2006 09:03:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932152AbWEGNDb (ORCPT ); Sun, 7 May 2006 09:03:31 -0400 Received: from master.altlinux.org ([62.118.250.235]:60428 "EHLO master.altlinux.org") by vger.kernel.org with ESMTP id S932151AbWEGNDb (ORCPT ); Sun, 7 May 2006 09:03:31 -0400 Date: Sun, 7 May 2006 17:03:20 +0400 From: Sergey Vlasov To: Michael Buesch Cc: akpm@osdl.org, Deepak Saxena , mbuesch@freenet.de, bcm43xx-dev@lists.berlios.de, linux-kernel@vger.kernel.org Subject: Re: [patch 2/6] New Generic HW RNG Message-Id: <20060507170320.3ce0d3e0.vsu@altlinux.ru> In-Reply-To: <20060507113604.778384000@pc1> References: <20060507113513.418451000@pc1> <20060507113604.778384000@pc1> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i586-alt-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg="PGP-SHA1"; boundary="Signature=_Sun__7_May_2006_17_03_20_+0400_3iiyTrtYVfsikK0a" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6211 Lines: 226 --Signature=_Sun__7_May_2006_17_03_20_+0400_3iiyTrtYVfsikK0a Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, 07 May 2006 13:35:15 +0200 Michael Buesch wrote: > Add a new generic H/W RNG core. >=20 > Signed-off-by: Michael Buesch [skip] > Index: hwrng/drivers/char/hw_random/core.c > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > --- /dev/null 1970-01-01 00:00:00.000000000 +0000 > +++ hwrng/drivers/char/hw_random/core.c 2006-05-07 01:04:42.000000000 +02= 00 > @@ -0,0 +1,324 @@ > +/* > + Added support for the AMD Geode LX RNG > + (c) Copyright 2004-2005 Advanced Micro Devices, Inc. > + > + derived from > + > + Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG) > + (c) Copyright 2003 Red Hat Inc > + > + derived from > + > + Hardware driver for the AMD 768 Random Number Generator (RNG) > + (c) Copyright 2001 Red Hat Inc > + > + derived from > + > + Hardware driver for Intel i810 Random Number Generator (RNG) > + Copyright 2000,2001 Jeff Garzik > + Copyright 2000,2001 Philipp Rumpf > + > + Added generic RNG API > + Copyright 2006 Michael Buesch > + Copyright 2005 (c) MontaVista Software, Inc. > + > + Please read Documentation/hw_random.txt for details on use. > + > + ---------------------------------------------------------- > + This software may be used and distributed according to the terms > + of the GNU General Public License, incorporated herein by refere= nce. > + > + */ > + > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > + > +#define RNG_MODULE_NAME "hw_random" > +#define PFX RNG_MODULE_NAME ": " > +#define RNG_MISCDEV_MINOR 183 /* official */ > + > + > +static struct hwrng *current_rng; > +static LIST_HEAD(rng_list); > +static DEFINE_MUTEX(rng_mutex); > + > + > +static int rng_dev_open(struct inode *inode, struct file *filp) > +{ > + /* enforce read-only access to this chrdev */ > + if ((filp->f_mode & FMODE_READ) =3D=3D 0) > + return -EINVAL; > + if (filp->f_mode & FMODE_WRITE) > + return -EINVAL; > + return 0; > +} > + > +static ssize_t rng_dev_read(struct file *filp, char __user *buf, > + size_t size, loff_t *offp) > +{ > + unsigned int have_data; > + u32 data =3D 0; > + ssize_t ret =3D 0; > + int i, err; > + > + while (size) { > + err =3D mutex_lock_interruptible(&rng_mutex); > + if (err) > + return err; This does not handle the case of partial read correctly - the code should be return ret ? : -ERESTARTSYS; > + if (!current_rng) { > + mutex_unlock(&rng_mutex); > + return -ENODEV; The same problem here (although finding the RNG suddenly missing after we heve just read something from it is pretty unlikely). > + } > + have_data =3D 0; > + if (current_rng->data_present =3D=3D NULL || > + current_rng->data_present(current_rng)) > + have_data =3D current_rng->data_read(current_rng, &data); > + mutex_unlock(&rng_mutex); > + > + while (have_data && size) { > + if (put_user((u8)data, buf++)) { > + ret =3D ret ? : -EFAULT; > + break; > + } > + size--; > + ret++; > + have_data--; > + data>>=3D8; > + } > + > + if (filp->f_flags & O_NONBLOCK) > + return ret ? : -EAGAIN; > + > + if (need_resched()) { > + schedule_timeout_interruptible(1); > + } else { > + err =3D mutex_lock_interruptible(&rng_mutex); > + if (err) > + return err; And here... > + if (!current_rng) { > + mutex_unlock(&rng_mutex); > + return -ENODEV; And here too. > + } > + for (i =3D 0; i < 20; i++) { > + if (current_rng->data_present =3D=3D NULL || > + current_rng->data_present(current_rng)) > + break; > + udelay(10); > + } > + mutex_unlock(&rng_mutex); > + } > + > + if (signal_pending(current)) > + return ret ? : -ERESTARTSYS; > + } > + return ret; > +} > + > + > +static struct file_operations rng_chrdev_ops =3D { > + .owner =3D THIS_MODULE, > + .open =3D rng_dev_open, > + .read =3D rng_dev_read, > +}; > + > +static struct miscdevice rng_miscdev =3D { > + .minor =3D RNG_MISCDEV_MINOR, > + .name =3D RNG_MODULE_NAME, > + .fops =3D &rng_chrdev_ops, > +}; > + > + > +static ssize_t hwrng_attr_current_store(struct class_device *class, > + const char *buf, size_t len) > +{ > + int err; > + struct hwrng *rng; > + > + if (!capable(CAP_SYS_ADMIN)) > + return -EPERM; > + > + err =3D mutex_lock_interruptible(&rng_mutex); > + if (err) > + return err; > + err =3D -ENODEV; > + list_for_each_entry(rng, &rng_list, list) { > + if (strncmp(rng->name, buf, len) =3D=3D 0) { This will match if the passed string is just a prefix of rng->name. Apparently sysfs guarantees that the buffer passed to ->store will be NUL-terminated, so this should be just a strcmp(). > + if (rng->init) { > + err =3D rng->init(rng); > + if (err) > + break; > + } > + if (current_rng && current_rng->cleanup) > + current_rng->cleanup(current_rng); What if rng =3D=3D current_rng here (someone has written the same RNG name to the "store" attribute)? The lowlevel RNG driver should not have to handle nested init/cleanup calls. [skip] --Signature=_Sun__7_May_2006_17_03_20_+0400_3iiyTrtYVfsikK0a Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.9.17 (GNU/Linux) iD8DBQFEXfAbW82GfkQfsqIRAgXKAJ41gohOuBIkh9fF3D7EITE8cQGrJgCeMcMX iZh7tmJGtiFnWBUqolO9NsY= =tcp4 -----END PGP SIGNATURE----- --Signature=_Sun__7_May_2006_17_03_20_+0400_3iiyTrtYVfsikK0a-- - 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/