If adapter->retries is set to a minus value from user space via ioctl,
it will make __i2c_transfer and __i2c_smbus_xfer skip the calling to
adapter->algo->master_xfer and adapter->algo->smbus_xfer that is
registered by the underlying bus drivers, and return value 0 to all the
callers. The bus driver will never be accessed anymore by all users,
besides, the users may still get successful return value without any
error or information log print out.
If adapter->timeout is set to minus value from user space via ioctl,
it will make the retrying loop in __i2c_transfer and __i2c_smbus_xfer
always break after the the first try, due to the time_after always
returns true.
Signed-off-by: Yi Zeng <yizeng@asrmicro.com>
[wsa: minor grammar updates to commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
i2cdev_ioctl_rdwr() allocates i2c_msg.buf using memdup_user(), which
returns ZERO_SIZE_PTR if i2c_msg.len is zero.
Currently i2cdev_ioctl_rdwr() always dereferences the buf pointer in case
of I2C_M_RD | I2C_M_RECV_LEN transfer. That causes a kernel oops in
case of zero len.
Let's check the len against zero before dereferencing buf pointer.
This issue was triggered by syzkaller.
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[wsa: use '< 1' instead of '!' for easier readability]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c_smbus_xfer() does not always fill an entire block, allowing
kernel stack memory disclosure through the temp variable. Clear
it before it's read to.
Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
There is no code protecting i2c_dev to be freed after it is returned
from i2c_dev_get_by_minor() and using it to access the value which we
already have (minor) isn't safe really.
Avoid using it and get the adapter directly from 'minor'.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The call to put_i2c_dev() frees "i2c_dev" so there is a use after
free when we call cdev_del(&i2c_dev->cdev).
Fixes: d6760b14d4 ('i2c: dev: switch from register_chrdev to cdev API')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
I stumbled multiple times over 'return_i2c_dev', especially before the
actual 'return res'. It makes the code hard to read, so reanme the
function to 'put_i2c_dev' which also better matches 'get_free_i2c_dev'.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c-dev had never moved away from the older register_chrdev interface to
implement its char device registration. The register_chrdev API has the
limitation of enabling only up to 256 i2c-dev busses to exist.
Large platforms with lots of i2c devices (i.e. pluggable transceivers)
with dedicated busses may have to exceed that limit.
In particular, there are also platforms making use of the i2c bus
multiplexing API, which instantiates a virtual bus for each possible
multiplexed selection.
This patch removes the register_chrdev usage and replaces it with the
less old cdev API, which takes away the 256 i2c-dev bus limitation.
It should not have any other impact for i2c bus drivers or user space.
This patch has been tested on qemu x86 and qemu powerpc platforms with
the aid of a module which adds and removes 5000 virtual i2c busses, as
well as validated on an existing powerpc hardware platform which makes
use of the i2c bus multiplexing API.
i2c-dev busses with device minor numbers larger than 256 have also been
validated to work with the existing i2c-tools.
Signed-off-by: Erico Nunes <erico.nunes@datacom.ind.br>
[wsa: kept includes sorted]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The first part of the comment is wrong since November 2007, delete it.
The second part of the comment is related to I2C_PEC, not I2C_SLAVE, so
move it where it belongs.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The ioctl is named I2C_RDWR for "I2C read/write". But references to it
were misspelled "rdrw". Fix them.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The 'name' attribute is needed for all i2c-dev class devices, meaning
it can be created automatically by pointing to it in the class data
structure. This simplifies the code and reduces the probability for race
conditions (the name attribute should exist by the time the device is
announced to user space).
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
As the bus driver side implementation of I2C_M_RECV_LEN is heavily
tied to SMBus, we can't support received length over 32 bytes, but
let's at least support that.
In practice, the caller will have to setup a buffer large enough to
cover the case where received length byte has value 32, so minimum
32 + 1 = 33 bytes, possibly more if there is a fixed number of bytes
added for the specific slave (for example a checksum.)
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Use memdup_user rather than duplicating its implementation.
This is a little bit restricted to reduce false positives.
The semantic patch that makes this output is available
in scripts/coccinelle/api/memdup_user.cocci.
More information about semantic patching is available at
http://coccinelle.lip6.fr/
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The function i2cdev_notifier_call is used only in i2c-dev file
making it static.
Also removes the following sparse warning
drivers/i2c/i2c-dev.c:582:5: warning: symbol 'i2cdev_notifier_call'
was not declared. Should it be static?
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Use the standard driver core mechanism to keep track of i2c adapters
present on the system: i2c_for_each_dev and a notifier. This will let
us deprecate and ultimately remove the legacy attach_adapter and
detach_adapter callbacks in i2c_driver.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add multiplexed bus core support. I2C multiplexer and switches
like pca954x get instantiated as new adapters per port.
Signed-off-by: Michael Lawnick <ml.lawnick@gmx.de>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Use memdup_user when user data is immediately copied into the allocated
region. Note that in the second case, the ++i is no longer necessary, as
the last value is already freed if needed by the call to memdup_user.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression from,to,size,flag;
position p;
identifier l1,l2;
@@
- to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+ to = memdup_user(from,size);
if (
- to==NULL
+ IS_ERR(to)
|| ...) {
<+... when != goto l1;
- -ENOMEM
+ PTR_ERR(to)
...+>
}
- if (copy_from_user(to, from, size) != 0) {
- <+... when != goto l2;
- -EFAULT
- ...+>
- }
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Fix all coding style issues found by checkpatch.pl.
Signed-off-by: Farid Hammane <farid.hammane@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The private_data member of struct file is a void *, there is no need
to cast it.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The BKL is held over a kmalloc so cannot protect anything beyond that.
The two calls before the kmalloc have their own locking.
Improve device open function by removing the now unnecessary ret variable
Signed-off-by: Vincent Sanders <vince@simtec.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The unit in which user-space can set the bus timeout value is jiffies
for historical reasons (back when HZ was always 100.) This is however
not good because user-space doesn't know how long a jiffy lasts. The
timeout value should instead be set in a fixed time unit. Given the
original value of HZ, this unit should be 10 ms, for compatibility.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
We need to convert the error pointer from class_create(), else we'll return the
successful return code from register_chrdev() on failure.
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Fix various printk format strings where %zd was passed a size_t;
those should be %zu instead. (Courtesy of a version of GCC which
warns when these details are wrong.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
device_create() is race-prone, so use the race-free
device_create_drvdata() instead as device_create() is going away.
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6: (56 commits)
i2c: Add detection capability to new-style drivers
i2c: Call client_unregister for new-style devices too
i2c: Clean up old chip drivers
i2c-ibm_iic: Register child nodes
i2c: New-style EEPROM driver using device IDs
i2c: Export the i2c_bus_type symbol
i2c-au1550: Fix PM support
i2c-dev: Delete empty detach_client callback
i2c: Drop stray references to lm_sensors
i2c: Check for ACPI resource conflicts
i2c-ocores: basic PM support
i2c-sibyte: SWARM I2C board initialization
i2c-i801: Fix handling of error conditions
i2c-i801: Rename local variable temp to status
i2c-i801: Properly report bus arbitration loss
i2c-i801: Remove verbose debugging messages
i2c-algo-pcf: Drop unused struct members
i2c-algo-pcf: Multi-master lost-arbitration improvement
i2c: Deprecate the legacy gpio drivers
i2c-pxa: Initialize early
...
Implementing detach_client is optional, so there is no point in
an empty implementation.
Likewise, i2c driver IDs are optional, and we don't need one.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This is part of the effort to get rid of the BKL.
[JD: In fact i2c-dev doesn't need more locking than is already done
for the other i2c drivers, so we can simply switch to unlocked_ioctl.]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Split the handling of the I2C_RDWR and I2C_SMBUS ioctls to their own
functions. This limits the stack usage, saves one level of indentation
and makes the code more readable.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The i2c_adapter.clients list of i2c_client nodes duplicates driver
model state. This patch starts removing that list, letting us remove
most existing users of those i2c-core lists.
* The core I2C code now iterates over the driver model's list instead
of the i2c-internal one in some places where it's safe:
- Passing a command/ioctl to each client, a mechanims
used almost exclusively by DVB adapters;
- Device address checking, in both i2c-core and i2c-dev.
* Provide i2c_verify_client() to use with driver model iterators.
* Flag the relevant i2c_adapter and i2c_client fields as deprecated,
to help prevent new users from appearing.
For the moment the list needs to stick around, since some issues show
up when deleting devices created by legacy I2C drivers. (They don't
follow standard driver model rules. Removing those devices can cause
self-deadlocks.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Let i2c-dev deal properly with new-style i2c clients. Instead of
considering them always busy, it needs to check wether a driver is
bound to them or not.
This is still not completely correct, as the client could become
busy later, but the same problem already existed before new-style
clients were introduced. We'll want to fix it someday.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
This adds some "how does this work" comments to the i2c-dev driver,
plus separators between the three main components:
- The parallel list of i2c_adapters ("i2c_dev_list"), each of which
gets a "struct i2c_dev" and a /dev/i2c-X character special file.
- An i2cdev_driver gets adapter add/remove notifications, which are
used to maintain that list of adapters.
- Special file operations, which let userspace talk either directly to
the adapter (for i2c_msg operations) or through cached addressing info
using an anonymous i2c_client (never registered anywhere).
Plus there's the usual module load/unload record keeping.
After making sense of this code, I think that the anonymous i2c_client
is pretty shady. But since it's never registered, using this code with
a system set up for "new style" I2C drivers is no more complicated than
always using the I2C_SLAVE_FORCE ioctl (instead of I2C_SLAVE).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This removes:
- An effectively unused hook: i2c_algorithm.algo_control.
- The i2c_control() call, used only by i2c-dev to call that
unused hook or set two barely supported adapter params.
(That param setting moves into i2c-dev.c ... still iffy
due to lack of locking, but no other changes.)
As shown by diffstat, this is a net code shrink. It also reduces the
complexity of the I2C adapter and /dev interfaces.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The I2C_M_RECV_LEN calling convention for i2c_mesg.flags involves
playing games with reported buffer lengths. (They start out less
than their actual size, and the length is then modified to reflect
how many bytes were delivered ... which one hopes is less than the
presumed actual size.) Refuse to play such error prone games across
the boundary between userspace and kernel.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Let the drivers specify how many bytes they want to read with
i2c_smbus_read_i2c_block_data(). So far, the block count was
hard-coded to I2C_SMBUS_BLOCK_MAX (32), which did not make much sense.
Many driver authors complained about this before, and I believe it's
about time to fix it. Right now, authors have to do technically stupid
things, such as individual byte reads or full-fledged I2C messaging,
to work around the problem. We do not want to encourage that.
I even found that some bus drivers (e.g. i2c-amd8111) already
implemented I2C block read the "right" way, that is, they didn't
follow the old, broken standard. The fact that it was never noticed
before just shows how little i2c_smbus_read_i2c_block_data() was used,
which isn't that surprising given how broken its prototype was so far.
There are some obvious compatiblity considerations:
* This changes the i2c_smbus_read_i2c_block_data() prototype. Users
outside the kernel tree will notice at compilation time, and will
have to update their code.
* User-space has access to i2c_smbus_xfer() directly using i2c-dev, so
the changed expectations would affect tools such as i2cdump. In order
to preserve binary compatibility, we give I2C_SMBUS_I2C_BLOCK_DATA
a new numeric value, and define I2C_SMBUS_I2C_BLOCK_BROKEN with the
old numeric value. When i2c-dev receives a transaction with the
old value, it can convert it to the new format on the fly.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Refactor kfree(i2c_dev) into return_i2c_dev(). This saves some
code and makes more sense, as the memory is allocated in
get_free_i2c_dev().
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
device_create() returns error code as pointer on failures.
This patch checks the return value of device_create() by using IS_ERR().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Remove extraneous whitespace from various i2c headers and core files,
like space-before-tab and whitespace at end of line.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
