From mboxrd@z Thu Jan 1 00:00:00 1970 From: Song Liu Subject: Re: [PATCH bpf-next 07/11] bpf: make sure to clear unused fields in tunnel/xfrm state fetch Date: Wed, 30 May 2018 10:15:33 -0700 Message-ID: References: <20180528004344.3606-1-daniel@iogearbox.net> <20180528004344.3606-8-daniel@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Alexei Starovoitov , Networking To: Daniel Borkmann Return-path: Received: from mail-qt0-f194.google.com ([209.85.216.194]:41848 "EHLO mail-qt0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753592AbeE3RPf (ORCPT ); Wed, 30 May 2018 13:15:35 -0400 Received: by mail-qt0-f194.google.com with SMTP id g13-v6so24197490qth.8 for ; Wed, 30 May 2018 10:15:34 -0700 (PDT) In-Reply-To: <20180528004344.3606-8-daniel@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, May 27, 2018 at 5:43 PM, Daniel Borkmann wrote: > Since the remaining bits are not filled in struct bpf_tunnel_key > resp. struct bpf_xfrm_state and originate from uninitialized stack > space, we should make sure to clear them before handing control > back to the program. > > Also add a padding element to struct bpf_xfrm_state for future use > similar as we have in struct bpf_tunnel_key and clear it as well. > > struct bpf_xfrm_state { > __u32 reqid; /* 0 4 */ > __u32 spi; /* 4 4 */ > __u16 family; /* 8 2 */ > > /* XXX 2 bytes hole, try to pack */ > > union { > __u32 remote_ipv4; /* 4 */ > __u32 remote_ipv6[4]; /* 16 */ > }; /* 12 16 */ > > /* size: 28, cachelines: 1, members: 4 */ > /* sum members: 26, holes: 1, sum holes: 2 */ > /* last cacheline: 28 bytes */ > }; > > Signed-off-by: Daniel Borkmann > Acked-by: Alexei Starovoitov Acked-by: Song Liu > --- > include/uapi/linux/bpf.h | 3 ++- > net/core/filter.c | 6 ++++++ > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index e2853aa..7108711 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -2214,7 +2214,7 @@ struct bpf_tunnel_key { > }; > __u8 tunnel_tos; > __u8 tunnel_ttl; > - __u16 tunnel_ext; > + __u16 tunnel_ext; /* Padding, future use. */ > __u32 tunnel_label; > }; > > @@ -2225,6 +2225,7 @@ struct bpf_xfrm_state { > __u32 reqid; > __u32 spi; /* Stored in network byte order */ > __u16 family; > + __u16 ext; /* Padding, future use. */ > union { > __u32 remote_ipv4; /* Stored in network byte order */ > __u32 remote_ipv6[4]; /* Stored in network byte order */ > diff --git a/net/core/filter.c b/net/core/filter.c > index 717c740..5ceb5e6 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -3445,6 +3445,7 @@ BPF_CALL_4(bpf_skb_get_tunnel_key, struct sk_buff *, skb, struct bpf_tunnel_key > to->tunnel_id = be64_to_cpu(info->key.tun_id); > to->tunnel_tos = info->key.tos; > to->tunnel_ttl = info->key.ttl; > + to->tunnel_ext = 0; > > if (flags & BPF_F_TUNINFO_IPV6) { > memcpy(to->remote_ipv6, &info->key.u.ipv6.src, > @@ -3452,6 +3453,8 @@ BPF_CALL_4(bpf_skb_get_tunnel_key, struct sk_buff *, skb, struct bpf_tunnel_key > to->tunnel_label = be32_to_cpu(info->key.label); > } else { > to->remote_ipv4 = be32_to_cpu(info->key.u.ipv4.src); > + memset(&to->remote_ipv6[1], 0, sizeof(__u32) * 3); > + to->tunnel_label = 0; > } > > if (unlikely(size != sizeof(struct bpf_tunnel_key))) > @@ -4047,11 +4050,14 @@ BPF_CALL_5(bpf_skb_get_xfrm_state, struct sk_buff *, skb, u32, index, > to->reqid = x->props.reqid; > to->spi = x->id.spi; > to->family = x->props.family; > + to->ext = 0; > + > if (to->family == AF_INET6) { > memcpy(to->remote_ipv6, x->props.saddr.a6, > sizeof(to->remote_ipv6)); > } else { > to->remote_ipv4 = x->props.saddr.a4; > + memset(&to->remote_ipv6[1], 0, sizeof(__u32) * 3); > } > > return 0; > -- > 2.9.5 >