From: Eric Dumazet edumazet@google.com

stable inclusion from stable-v4.19.317 commit 06f208ae0670ef97b0bf253a5523863e113026b6 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAMPH5

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

---------------------------

[ Upstream commit d37fe4255abe8e7b419b90c5847e8ec2b8debb08 ]

tcp_v6_syn_recv_sock() calls ip6_dst_store() before inet_sk(newsk)->pinet6 has been set up.

This means ip6_dst_store() writes over the parent (listener) np->dst_cookie.

This is racy because multiple threads could share the same parent and their final np->dst_cookie could be wrong.

Move ip6_dst_store() call after inet_sk(newsk)->pinet6 has been changed and after the copy of parent ipv6_pinfo.

Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Signed-off-by: Eric Dumazet edumazet@google.com Reviewed-by: Simon Horman horms@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yue Haibing yuehaibing@huawei.com --- net/ipv6/tcp_ipv6.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index e3878cf00dd4..4d9c9fbef8b9 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1176,7 +1176,6 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * */

newsk->sk_gso_type = SKB_GSO_TCPV6; - ip6_dst_store(newsk, dst, NULL, NULL); inet6_sk_rx_dst_set(newsk, skb);

newtcp6sk = (struct tcp6_sock *)newsk; @@ -1188,6 +1187,8 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *

memcpy(newnp, np, sizeof(struct ipv6_pinfo));

+ ip6_dst_store(newsk, dst, NULL, NULL); + newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr; newnp->saddr = ireq->ir_v6_loc_addr; newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;