01c4ceae0a
The hdlc_rcv function is used as hdlc_packet_type.func to process any
skb received in the kernel with skb->protocol == htons(ETH_P_HDLC).
The purpose of this function is to provide second-stage processing for
skbs not assigned a "real" L3 skb->protocol value in the first stage.
This function assumes the device from which the skb is received is an
HDLC device (a device created by this module). It assumes that
netdev_priv(dev) returns a pointer to "struct hdlc_device".
However, it is possible that some driver in the kernel (not necessarily
in our control) submits a received skb with skb->protocol ==
htons(ETH_P_HDLC), from a non-HDLC device. In this case, the skb would
still be received by hdlc_rcv. This will cause problems.
hdlc_rcv should be able to recognize and drop invalid skbs. It should
first make sure "dev" is actually an HDLC device, before starting its
processing. This patch adds this check to hdlc_rcv.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Link: https://lore.kernel.org/r/20201020013152.89259-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski <kuba@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.
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.