89aa3619d1
As the comment in this function says, the code currently just clears the CIPSO part with IPOPT_NOP, rather than removing it completely and trimming the packet. The other cipso_v4_*_delattr() functions, however, do the proper removal and also calipso_skbuff_delattr() makes an effort to remove the CALIPSO options instead of replacing them with padding. Some routers treat IPv4 packets with anything (even NOPs) in the option header as a special case and take them through a slower processing path. Consequently, hardening guides such as STIG recommend to configure such routers to drop packets with non-empty IP option headers [1][2]. Thus, users might expect NetLabel to produce packets with minimal padding (or at least with no padding when no actual options are present). Implement the proper option removal to address this and to be closer to what the peer functions do. [1] https://www.stigviewer.com/stig/juniper_router_rtr/2019-09-27/finding/V-90937 [2] https://www.stigviewer.com/stig/cisco_ios_xe_router_rtr/2021-03-26/finding/V-217001 Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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 reStructuredText markup notation.
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.