Hello, On Tue, 11 Aug 2020, Peilin Ye wrote: > do_ip_vs_set_ctl() is referencing uninitialized stack value when `len` is > zero. Fix it. > > Reported-by: syzbot+23b5f9e7caf61d9a3898@xxxxxxxxxxxxxxxxxxxxxxxxx > Link: https://syzkaller.appspot.com/bug?id=46ebfb92a8a812621a001ef04d90dfa459520fe2 > Suggested-by: Julian Anastasov <ja@xxxxxx> > Signed-off-by: Peilin Ye <yepeilin.cs@xxxxxxxxx> Looks good to me, thanks! Acked-by: Julian Anastasov <ja@xxxxxx> > --- > Changes in v2: > - Target net-next tree. (Suggested by Julian Anastasov <ja@xxxxxx>) > - Reject all `len == 0` requests except `IP_VS_SO_SET_FLUSH`, instead > of initializing `arg`. (Suggested by Cong Wang > <xiyou.wangcong@xxxxxxxxx>, Julian Anastasov <ja@xxxxxx>) > > net/netfilter/ipvs/ip_vs_ctl.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c > index 412656c34f20..beeafa42aad7 100644 > --- a/net/netfilter/ipvs/ip_vs_ctl.c > +++ b/net/netfilter/ipvs/ip_vs_ctl.c > @@ -2471,6 +2471,10 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) > /* Set timeout values for (tcp tcpfin udp) */ > ret = ip_vs_set_timeout(ipvs, (struct ip_vs_timeout_user *)arg); > goto out_unlock; > + } else if (!len) { > + /* No more commands with len == 0 below */ > + ret = -EINVAL; > + goto out_unlock; > } > > usvc_compat = (struct ip_vs_service_user *)arg; > @@ -2547,9 +2551,6 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) > break; > case IP_VS_SO_SET_DELDEST: > ret = ip_vs_del_dest(svc, &udest); > - break; > - default: > - ret = -EINVAL; > } > > out_unlock: > -- > 2.25.1 Regards -- Julian Anastasov <ja@xxxxxx>
