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Wenwen Wang
72c25b9bf7
[ Upstream commit 0781168e23 ]
In yam_ioctl(), the concrete ioctl command is firstly copied from the
user-space buffer 'ifr->ifr_data' to 'ioctl_cmd' and checked through the
following switch statement. If the command is not as expected, an error
code EINVAL is returned. In the following execution the buffer
'ifr->ifr_data' is copied again in the cases of the switch statement to
specific data structures according to what kind of ioctl command is
requested. However, after the second copy, no re-check is enforced on the
newly-copied command. Given that the buffer 'ifr->ifr_data' is in the user
space, a malicious user can race to change the command between the two
copies. This way, the attacker can inject inconsistent data and cause
undefined behavior.
This patch adds a re-check in each case of the switch statement if there is
a second copy in that case, to re-check whether the command obtained in the
second copy is the same as the one in the first copy. If not, an error code
EINVAL will be returned.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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.