[PATCH bpf-next v3 07/11] bpf: make sure to clear unused fields in tunnel/xfrm state fetch
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2018-06-02 21:07:15
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <redacted>
---
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 6613181..f0b6608 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -2268,7 +2268,7 @@ struct bpf_tunnel_key { }; __u8 tunnel_tos; __u8 tunnel_ttl; - __u16 tunnel_ext; + __u16 tunnel_ext; /* Padding, future use. */ __u32 tunnel_label; };
@@ -2279,6 +2279,7 @@ 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 edbfaa6..28e8647 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