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From:   zhanggenjian <zhanggenjian123@gmail.com>
To:     pabeni@redhat.com, edumazet@google.com, davem@davemloft.net,
        yoshfuji@linux-ipv6.org, dsahern@kernel.org, kuba@kernel.org
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        huhai@kylinos.cn, zhanggenjian123@gmail.com
Subject: [PATCH v2] net: ipv4: Avoid bounds check warning
Date:   Thu, 26 May 2022 18:12:13 +0800
Message-Id: <20220526101213.2392980-1-zhanggenjian@kylinos.cn>
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From: huhai <huhai@kylinos.cn>

Fix the following build warning when CONFIG_IPV6 is not set:

In function ‘fortify_memcpy_chk’,
    inlined from ‘tcp_md5_do_add’ at net/ipv4/tcp_ipv4.c:1210:2:
./include/linux/fortify-string.h:328:4: error: call to ‘__write_overflow_field’ declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
  328 |    __write_overflow_field(p_size_field, size);
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: huhai <huhai@kylinos.cn>
---
 net/ipv4/tcp_ipv4.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 457f5b5d5d4a..46ae9d535086 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1208,8 +1208,8 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 	key->l3index = l3index;
 	key->flags = flags;
 	memcpy(&key->addr, addr,
-	       (family == AF_INET6) ? sizeof(struct in6_addr) :
-				      sizeof(struct in_addr));
+	       (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
+								 sizeof(struct in_addr));
 	hlist_add_head_rcu(&key->node, &md5sig->head);
 	return 0;
 }
-- 
2.27.0