[patch -next] net: writes past the end of the struct
From: Dan Carpenter <hidden>
Date: 2012-07-11 06:33:00
Also in:
kernel-janitors
Subsystem:
networking [general], networking [ipsec], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Steffen Klassert, Herbert Xu, David Ahern, Ido Schimmel, Linus Torvalds
There are a couple places that try to set part of the struct to 0 by
doing:
memset(&rt->rt6i_table, 0, sizeof(*rt) - sizeof(struct dst_entry));
It assumes that the first element is a dst_entry and the second element
is ->rt6_table. The problem is we changed the struct in 97cac0821a
('ipv6: Store route neighbour in rt6_info struct.') and we aren't
clearing rt->n but instead we're writing past the end of the array.
I've changed it to:
memset(&rt->n, 0, sizeof(*rt) - offsetof(struct rt6_info, n));
The memset in ip6_dst_alloc() was ok but I changed it to use offsetof()
as a cleanup.
Signed-off-by: Dan Carpenter <redacted>
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 6e97855..c2186a7 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c@@ -1353,8 +1353,8 @@ static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family) xdst = dst_alloc(dst_ops, NULL, 0, 0, 0); if (likely(xdst)) { - memset(&xdst->u.rt6.rt6i_table, 0, - sizeof(*xdst) - sizeof(struct dst_entry)); + memset(&xdst->u.rt6.n, 0, + sizeof(*xdst) - offsetof(struct rt6_info, n)); xdst->flo.ops = &xfrm_bundle_fc_ops; } else xdst = ERR_PTR(-ENOBUFS);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 6cc6c88..41693f6 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c@@ -274,7 +274,7 @@ static inline struct rt6_info *ip6_dst_alloc(struct net *net, if (rt) { memset(&rt->n, 0, - sizeof(*rt) - sizeof(struct dst_entry)); + sizeof(*rt) - offsetof(struct rt6_info, n)); rt6_init_peer(rt, table ? &table->tb6_peers : net->ipv6.peers); } return rt;
@@ -975,7 +975,7 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori rt = dst_alloc(&ip6_dst_blackhole_ops, ort->dst.dev, 1, 0, 0); if (rt) { - memset(&rt->rt6i_table, 0, sizeof(*rt) - sizeof(struct dst_entry)); + memset(&rt->n, 0, sizeof(*rt) - offsetof(struct rt6_info, n)); rt6_init_peer(rt, net->ipv6.peers); new = &rt->dst;