net: Use sockaddr_storage for getsockopt(SO_PEERNAME).

[ Upstream commit 8936bf53a091ad6a34b480c22002f1cb2422ab38 ]

Commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3") started
applying strict rules to standard string functions.

It does not work well with conventional socket code around each protocol-
specific sockaddr_XXX struct, which is cast from sockaddr_storage and has
a bigger size than fortified functions expect.  See these commits:

 commit 06d4c8a80836 ("af_unix: Fix fortify_panic() in unix_bind_bsd().")
 commit ecb4534b6a1c ("af_unix: Terminate sun_path when bind()ing pathname socket.")
 commit a0ade8404c3b ("af_packet: Fix warning of fortified memcpy() in packet_getname().")

We must cast the protocol-specific address back to sockaddr_storage
to call such functions.

However, in the case of getsockaddr(SO_PEERNAME), the rationale is a bit
unclear as the buffer is defined by char[128] which is the same size as
sockaddr_storage.

Let's use sockaddr_storage explicitly.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/core/sock.c b/net/core/sock.c
index e5858fa5d6d57fcd193c40a39a19a82f927f4c9a..0ee2e33bbe5f8008153070e3f01cb651521c513a 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1774,14 +1774,14 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
 
        case SO_PEERNAME:
        {
-               char address[128];
+               struct sockaddr_storage address;
 
-               lv = sock->ops->getname(sock, (struct sockaddr *)address, 2);
+               lv = sock->ops->getname(sock, (struct sockaddr *)&address, 2);
                if (lv < 0)
                        return -ENOTCONN;
                if (lv < len)
                        return -EINVAL;
-               if (copy_to_sockptr(optval, address, len))
+               if (copy_to_sockptr(optval, &address, len))
                        return -EFAULT;
                goto lenout;
        }