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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Francesco Ruggeri <fruggeri@arista.com>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 067/129] tcp: md5: incorrect tcp_header_len for incoming connections
Date:   Wed,  4 May 2022 18:44:19 +0200
Message-Id: <20220504153026.578788965@linuxfoundation.org>
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From: Francesco Ruggeri <fruggeri@arista.com>

[ Upstream commit 5b0b9e4c2c895227c8852488b3f09839233bba54 ]

In tcp_create_openreq_child we adjust tcp_header_len for md5 using the
remote address in newsk. But that address is still 0 in newsk at this
point, and it is only set later by the callers (tcp_v[46]_syn_recv_sock).
Use the address from the request socket instead.

Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.")
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220421005026.686A45EC01F2@us226.sjc.aristanetworks.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/tcp_minisocks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index f0f67b25c97a..62f5ef9e6f93 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -538,7 +538,7 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 	newtp->tsoffset = treq->ts_off;
 #ifdef CONFIG_TCP_MD5SIG
 	newtp->md5sig_info = NULL;	/*XXX*/
-	if (newtp->af_specific->md5_lookup(sk, newsk))
+	if (treq->af_specific->req_md5_lookup(sk, req_to_sk(req)))
 		newtp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED;
 #endif
 	if (skb->len >= TCP_MSS_DEFAULT + newtp->tcp_header_len)
-- 
2.35.1