CVS commit: src/sys/net

["Maxime Villard" <maxv%netbsd.org@localhost>]

Module Name:    src
Committed By:   maxv
Date:           Tue May 29 08:24:59 UTC 2018

Modified Files:
        src/sys/net: if_ethersubr.c

Log Message:
Replace KASSERT by m_pullup. While the ethernet header is always there
when the packet was received on a physical interface, it may not be if
the packet was received over L2TP/EtherIP.

In particular, if the inner ethernet header ends up on two separate IP
fragments. Here the KASSERT is triggered, and on !DIAGNOSTIC we corrupt
memory.

Note that this is a widespread problem: a lot of L2 code was written with
the assumption that "most" headers are present in the first mbuf.
Obviously, that's not true if L2 encapsulation is being used.


To generate a diff of this commit:
cvs rdiff -u -r1.266 -r1.267 src/sys/net/if_ethersubr.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.