commit e9c46600cdf19bd790a0a2e2aeb6675f61d3aed5
author Guillaume Nault <g.nault@alphalink.fr> Mon Apr 23 16:15:14 2018 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Sun Apr 29 11:32:00 2018 +0200
tree 67d46a5ac0e6c81c2df698aee984738dc93e1dfc
parent 06a02a81689074406d70979837518b1f747767af

l2tp: check sockaddr length in pppol2tp_connect()

[ Upstream commit eb1c28c05894a4b1f6b56c5bf072205e64cfa280 ]

Check sockaddr_len before dereferencing sp->sa_protocol, to ensure that
it actually points to valid data.

Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Reported-by: syzbot+a70ac890b23b1bf29f5c@syzkaller.appspotmail.com
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>