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c9318a3e02
In twa_chrdev_ioctl(), the ioctl driver command is firstly copied from the userspace pointer 'argp' and saved to the kernel object 'driver_command'. Then a security check is performed on the data buffer size indicated by 'driver_command', which is 'driver_command.buffer_length'. If the security check is passed, the entire ioctl command is copied again from the 'argp' pointer and saved to the kernel object 'tw_ioctl'. Then, various operations are performed on 'tw_ioctl' according to the 'cmd'. Given that the 'argp' pointer resides in userspace, a malicious userspace process can race to change the buffer size between the two copies. This way, the user can bypass the security check and inject invalid data buffer size. This can cause potential security issues in the following execution. This patch checks for capable(CAP_SYS_ADMIN) in twa_chrdev_open()t o avoid the above issues. Signed-off-by: Wenwen Wang <wang6495@umn.edu> Acked-by: Adam Radford <aradford@gmail.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.