23a27722b5
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.