linux-stable.git/drivers/i2c/i2c-dev.c, branch linux-6.3.y

i2c: dev: Fix bus callback return values

2023-03-09T21:07:52+00:00

The i2cdev_{at,de}tach_adapter() callbacks are used for two purposes:
  1. As notifier callbacks, when (un)registering I2C adapters created or
     destroyed after i2c_dev_init(),
  2. As bus iterator callbacks, for registering already existing
     adapters from i2c_dev_init(), and for cleanup.

Unfortunately both use cases expect different return values: the former
expects NOTIFY_* return codes, while the latter expects zero or error
codes, and aborts in case of error.

Hence in case 2, as soon as i2cdev_{at,de}tach_adapter() returns
(non-zero) NOTIFY_OK, the bus iterator aborts.  This causes (a) only the
first already existing adapter to be registered, leading to missing
/dev/i2c-* entries, and (b) a failure to unregister all but the first
I2C adapter during cleanup.

Fix this by introducing separate callbacks for the bus iterator,
wrapping the notifier functions, and always returning succes.
Any errors inside these callback functions are unlikely to happen, and
are fatal anyway.

Fixes: cddf70d0bce71c2a ("i2c: dev: fix notifier return values")
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Bartosz Golaszewski 
Signed-off-by: Wolfram Sang

i2c: dev: fix notifier return values

2023-01-17T10:02:21+00:00

We have a set of return values that notifier callbacks can return. They
should not return 0, error codes or anything other than those predefined
values. Make the i2c character device's callback return NOTIFY_DONE or
NOTIFY_OK depending on the situation.

Signed-off-by: Bartosz Golaszewski 
Signed-off-by: Wolfram Sang

i2c: dev: Force case user pointers in compat_i2cdev_ioctl()

2022-04-15T21:30:59+00:00

Sparse has warned us about wrong address space for user pointers:

  i2c-dev.c:561:50: warning: incorrect type in initializer (different address spaces)
  i2c-dev.c:561:50:    expected unsigned char [usertype] *buf
  i2c-dev.c:561:50:    got void [noderef] __user *

Force cast the pointer to (__u8 *) that is used by I²C core code.

Note, this is an additional fix to the previously addressed similar issue
in the I2C_RDWR case in the same function.

Fixes: 3265a7e6b41b ("i2c: dev: Add __user annotation")
Signed-off-by: Andy Shevchenko 
Signed-off-by: Wolfram Sang

i2c: dev: check return value when calling dev_set_name()

2022-04-15T21:23:22+00:00

If dev_set_name() fails, the dev_name() is null, check the return
value of dev_set_name() to avoid the null-ptr-deref.

Fixes: 1413ef638aba ("i2c: dev: Fix the race between the release of i2c_dev and cdev")
Signed-off-by: Andy Shevchenko 
Signed-off-by: Wolfram Sang

i2c: validate user data in compat ioctl

2021-12-31T13:28:22+00:00

Wrong user data may cause warning in i2c_transfer(), ex: zero msgs.
Userspace should not be able to trigger warnings, so this patch adds
validation checks for user data in compact ioctl to prevent reported
warnings

Reported-and-tested-by: syzbot+e417648b303855b91d8a@syzkaller.appspotmail.com
Fixes: 7d5cb45655f2 ("i2c compat ioctls: move to ->compat_ioctl()")
Signed-off-by: Pavel Skripkin 
Signed-off-by: Wolfram Sang

Merge branch 'i2c/for-mergewindow' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

2021-08-31T21:34:01+00:00

Pull i2c updates from Wolfram Sang:
 "I2C has a smaller pull reuest this time:

   - new driver for I2C virtio

   - removal of PMC SMP driver because platform is already gone

   - IRQ probing and DMAENGINE API cleanups

   - add SI metric prefix definitions to units.h

   - beginning of i801 refactorization

   - a few driver improvements"

* 'i2c/for-mergewindow' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (28 commits)
  i2c: cadence: Implement save restore
  i2c: xlp9xx: fix main IRQ check
  i2c: mt65xx: fix IRQ check
  i2c: virtio: add a virtio i2c frontend driver
  i2c: hix5hd2: fix IRQ check
  i2c: s3c2410: fix IRQ check
  i2c: iop3xx: fix deferred probing
  i2c: synquacer: fix deferred probing
  i2c: sun6i-pw2i: Prefer strscpy over strlcpy
  i2c: remove dead PMC MSP TWI/SMBus/I2C driver
  i2c: dev: Use sysfs_emit() in "show" functions
  i2c: dev: Define pr_fmt() and drop duplication substrings
  i2c: designware: Fix indentation in the header
  i2c: designware: Use DIV_ROUND_CLOSEST() macro
  units: Add SI metric prefix definitions
  i2c: at91: mark PM ops as __maybe unused
  i2c: sh_mobile: : use proper DMAENGINE API for termination
  i2c: qup: : use proper DMAENGINE API for termination
  i2c: mxs: : use proper DMAENGINE API for termination
  i2c: imx: : use proper DMAENGINE API for termination
  ...

i2c: dev: Use sysfs_emit() in "show" functions

2021-08-11T14:48:51+00:00

The sysfs_emit() function was introduced to make it less ambiguous
which function is preferred when writing to the output buffer in
a "show" callback [1].

Convert the I²C device sysfs interface from sprintf() to sysfs_emit()
accordingly, as the latter is aware of the PAGE_SIZE buffer and correctly
returns the number of bytes written into the buffer.

No functional change intended.

[1] Documentation/filesystems/sysfs.rst

Signed-off-by: Andy Shevchenko 
Signed-off-by: Wolfram Sang

i2c: dev: Define pr_fmt() and drop duplication substrings

2021-08-11T14:46:41+00:00

Define pr_fmt() to print module name as prefix and at the same time
drop duplication substrings in the messages.

While at it, convert printk() to pr_().

Signed-off-by: Andy Shevchenko 
Signed-off-by: Wolfram Sang

i2c: dev: zero out array used for i2c reads from userspace

2021-08-10T20:54:10+00:00

If an i2c driver happens to not provide the full amount of data that a
user asks for, it is possible that some uninitialized data could be sent
to userspace.  While all in-kernel drivers look to be safe, just be sure
by initializing the buffer to zero before it is passed to the i2c driver
so that any future drivers will not have this issue.

Also properly copy the amount of data recvieved to the userspace buffer,
as pointed out by Dan Carpenter.

Reported-by: Eric Dumazet 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Wolfram Sang

i2c: dev: Add __user annotation

2021-06-24T19:47:43+00:00

Fix Sparse warnings:
drivers/i2c/i2c-dev.c:546:19: warning: incorrect type in assignment (different address spaces)
drivers/i2c/i2c-dev.c:549:53: warning: incorrect type in argument 2 (different address spaces)

compat_ptr() returns a pointer tagged __user which gets assigned to a
pointer missing the __user annotation. The same pointer is passed to
copy_from_user() as an argument where it is expected to have the __user
annotation. Fix both by adding the __user annotation to the pointer.

Fixes: 7d5cb45655f2 ("i2c compat ioctls: move to ->compat_ioctl()")
Signed-off-by: Andreas Hecht 
Signed-off-by: Wolfram Sang