c4e9e09f55
1) Only accept packets with original datagram len field >= header len.
The extension header must start after the original datagram headers.
The embedded datagram len field is compared against the 128B minimum
stipulated by RFC 4884. It is unlikely that headers extend beyond
this. But as we know the exact header length, check explicitly.
2) Remove the check that datagram length must be <= 576B.
This is a send constraint. There is no value in testing this on rx.
Within private networks it may be known safe to send larger packets.
Process these packets.
This test was also too lax. It compared original datagram length
rather than entire icmp packet length. The stand-alone fix would be:
- if (hlen + skb->len > 576)
+ if (-skb_network_offset(skb) + skb->len > 576)
Fixes: eba75c587e81 ("icmp: support rfc 4884")
Signed-off-by: Willem de Bruijn <willemb@google.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 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.