4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guillaume Nault <g.nault@xxxxxxxxxxxx> [ Upstream commit a49e2f5d5fb141884452ddb428f551b123d436b5 ] We must validate sockaddr_len, otherwise userspace can pass fewer data than we expect and we end up accessing invalid data. Fixes: 224cf5ad14c0 ("ppp: Move the PPP drivers") Reported-by: syzbot+4f03bdf92fdf9ef5ddab@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Guillaume Nault <g.nault@xxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ppp/pppoe.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/ppp/pppoe.c +++ b/drivers/net/ppp/pppoe.c @@ -638,6 +638,10 @@ static int pppoe_connect(struct socket * lock_sock(sk); error = -EINVAL; + + if (sockaddr_len != sizeof(struct sockaddr_pppox)) + goto end; + if (sp->sa_protocol != PX_PROTO_OE) goto end;