[PATCH net 2/2] tipc: fix possible crash in __tipc_nl_net_set()

[Eric Dumazet]

syzbot reported a crash in __tipc_nl_net_set() caused by NULL dereference.

We need to check that both TIPC_NLA_NET_NODEID and TIPC_NLA_NET_NODEID_W1
are present.

We also need to make sure userland provided u64 attributes.

Fixes: d50ccc2d3909 ("tipc: add 128-bit node identifier")
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Jon Maloy <jon.ma...@ericsson.com>
Cc: Ying Xue <ying....@windriver.com>
Reported-by: syzbot <syzkal...@googlegroups.com>
---
 net/tipc/net.c     | 2 ++
 net/tipc/netlink.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/net/tipc/net.c b/net/tipc/net.c
index 
856f9e97ea293210bea1d2003d2092482732ace9..4fbaa0464405370601cb2fd1dd3b03733836d342
 100644
--- a/net/tipc/net.c
+++ b/net/tipc/net.c
@@ -252,6 +252,8 @@ int __tipc_nl_net_set(struct sk_buff *skb, struct genl_info 
*info)
                u64 *w0 = (u64 *)&node_id[0];
                u64 *w1 = (u64 *)&node_id[8];
 
+               if (!attrs[TIPC_NLA_NET_NODEID_W1])
+                       return -EINVAL;
                *w0 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID]);
                *w1 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID_W1]);
                tipc_net_init(net, node_id, 0);
diff --git a/net/tipc/netlink.c b/net/tipc/netlink.c
index 
d4e0bbeee72793a060befaf8a9d0239731c0d48c..6ff2254088f647d4f7410c3335ccdae2e68ec522
 100644
--- a/net/tipc/netlink.c
+++ b/net/tipc/netlink.c
@@ -81,6 +81,8 @@ const struct nla_policy tipc_nl_net_policy[TIPC_NLA_NET_MAX + 
1] = {
        [TIPC_NLA_NET_UNSPEC]           = { .type = NLA_UNSPEC },
        [TIPC_NLA_NET_ID]               = { .type = NLA_U32 },
        [TIPC_NLA_NET_ADDR]             = { .type = NLA_U32 },
+       [TIPC_NLA_NET_NODEID]           = { .type = NLA_U64 },
+       [TIPC_NLA_NET_NODEID_W1]        = { .type = NLA_U64 },
 };
 
 const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
-- 
2.17.0.484.g0c8726318c-goog