Add a check for a NULL mbuf ptr at the beginning of xdrmbuf_inline() so that it returns failure instead of crashing when "m->m_len" is executed and m == NULL. The mbuf ptr can be NULL when a call to xdrmbuf_getbytes() gets the bytes it needs, but they are at the end of a short RPC reply. When this happens, xdrmbuf_getbytes() returns success, but advances the mbuf ptr (xdrs->x_private) to m_next, which is NULL. If this is followed by a call to xdrmbuf_getlong(), it calls xdrmbuf_inline(), which would cause a crash by accessing "m->m_len".
Add a check for a NULL mbuf ptr at the beginning of xdrmbuf_inline()
so that it returns failure instead of crashing when "m->m_len" is
executed and m == NULL. The mbuf ptr can be NULL when a call to
xdrmbuf_getbytes() gets the bytes it needs, but they are at the end
of a short RPC reply. When this happens, xdrmbuf_getbytes() returns
success, but advances the mbuf ptr (xdrs->x_private) to m_next, which
is NULL. If this is followed by a call to xdrmbuf_getlong(), it calls
xdrmbuf_inline(), which would cause a crash by accessing "m->m_len".

Tested by:	pho, serenity at exscape dot org
Approved by:	re (rwatson), kib (mentor)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase