From 92a0d7e20fe47c91427b84b2644d8f8881d98aef Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@google.com>
Date: Mon, 29 Apr 2024 10:16:24 +0000
Subject: [PATCH] Revert "net: dev: Convert sa_data to flexible array in struct
 sockaddr"

This reverts commit f6ce90567ed373b6be96a033fda73cd769f5c748 which is
commit b5f0de6df6dce8d641ef58ef7012f3304dffb9a1 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I809e53c4e3449a45ecd1fdec260986011b88206e
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
---
 include/linux/socket.h |  5 +----
 net/core/dev.c         |  2 +-
 net/core/dev_ioctl.c   |  2 +-
 net/packet/af_packet.c | 10 +++++-----
 4 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/include/linux/socket.h b/include/linux/socket.h
index daf51fef5a8d..c3b35d18bcd3 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -31,10 +31,7 @@ typedef __kernel_sa_family_t	sa_family_t;
 
 struct sockaddr {
 	sa_family_t	sa_family;	/* address family, AF_xxx	*/
-	union {
-		char sa_data_min[14];		/* Minimum 14 bytes of protocol address	*/
-		DECLARE_FLEX_ARRAY(char, sa_data);
-	};
+	char		sa_data[14];	/* 14 bytes of protocol address	*/
 };
 
 struct linger {
diff --git a/net/core/dev.c b/net/core/dev.c
index efd4f61735c6..a09821cc047a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8792,7 +8792,7 @@ EXPORT_SYMBOL(dev_set_mac_address_user);
 
 int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name)
 {
-	size_t size = sizeof(sa->sa_data_min);
+	size_t size = sizeof(sa->sa_data);
 	struct net_device *dev;
 	int ret = 0;
 
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 60e815a71909..993420da2930 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -245,7 +245,7 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
 		if (ifr->ifr_hwaddr.sa_family != dev->type)
 			return -EINVAL;
 		memcpy(dev->broadcast, ifr->ifr_hwaddr.sa_data,
-		       min(sizeof(ifr->ifr_hwaddr.sa_data_min),
+		       min(sizeof(ifr->ifr_hwaddr.sa_data),
 			   (size_t)dev->addr_len));
 		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
 		return 0;
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 6cc054dd53b6..1052cbcdd3c8 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3252,7 +3252,7 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr,
 			    int addr_len)
 {
 	struct sock *sk = sock->sk;
-	char name[sizeof(uaddr->sa_data_min) + 1];
+	char name[sizeof(uaddr->sa_data) + 1];
 
 	/*
 	 *	Check legality
@@ -3263,8 +3263,8 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr,
 	/* uaddr->sa_data comes from the userspace, it's not guaranteed to be
 	 * zero-terminated.
 	 */
-	memcpy(name, uaddr->sa_data, sizeof(uaddr->sa_data_min));
-	name[sizeof(uaddr->sa_data_min)] = 0;
+	memcpy(name, uaddr->sa_data, sizeof(uaddr->sa_data));
+	name[sizeof(uaddr->sa_data)] = 0;
 
 	return packet_do_bind(sk, name, 0, 0);
 }
@@ -3536,11 +3536,11 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
 		return -EOPNOTSUPP;
 
 	uaddr->sa_family = AF_PACKET;
-	memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data_min));
+	memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data));
 	rcu_read_lock();
 	dev = dev_get_by_index_rcu(sock_net(sk), READ_ONCE(pkt_sk(sk)->ifindex));
 	if (dev)
-		strscpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data_min));
+		strscpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data));
 	rcu_read_unlock();
 
 	return sizeof(*uaddr);