[PATCH] net: prevent address rewrite in kernel_bind()

[PATCH] net: prevent address rewrite in kernel_bind()

[Jordan Rife]

commit c889a99a21bf124c3db08d09df919f0eccc5ea4c upstream.

Fix merge conflicts, so this patch can be backported to 4.19+.

Similar to the change in commit 0bdf399342c5("net: Avoid address
overwrite in kernel_connect"), BPF hooks run on bind may rewrite the
address passed to kernel_bind(). This change

1) Makes a copy of the bind address in kernel_bind() to insulate
   callers.
2) Replaces direct calls to sock->ops->bind() in net with kernel_bind()

Link: https://lore.kernel.org/netdev/20230912013332.2048422-1-jrife@google.com/
Fixes: 4fbac77d2d09 ("bpf: Hooks for sys_bind")
Cc: stable@vger.kernel.org
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jordan Rife <jrife@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/netfilter/ipvs/ip_vs_sync.c | 4 ++--
 net/rds/tcp_connect.c           | 2 +-
 net/rds/tcp_listen.c            | 2 +-
 net/socket.c                    | 6 +++++-
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 264f2f87a4376..bc7b71c9d28ab 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -1441,7 +1441,7 @@ static int bind_mcastif_addr(struct socket *sock, struct net_device *dev)
 	sin.sin_addr.s_addr  = addr;
 	sin.sin_port         = 0;
 
-	return sock->ops->bind(sock, (struct sockaddr*)&sin, sizeof(sin));
+	return kernel_bind(sock, (struct sockaddr *)&sin, sizeof(sin));
 }
 
 static void get_mcast_sockaddr(union ipvs_sockaddr *sa, int *salen,
@@ -1548,7 +1548,7 @@ static int make_receive_sock(struct netns_ipvs *ipvs, int id,
 
 	get_mcast_sockaddr(&mcast_addr, &salen, &ipvs->bcfg, id);
 	sock->sk->sk_bound_dev_if = dev->ifindex;
-	result = sock->ops->bind(sock, (struct sockaddr *)&mcast_addr, salen);
+	result = kernel_bind(sock, (struct sockaddr *)&mcast_addr, salen);
 	if (result < 0) {
 		pr_err("Error binding to the multicast addr\n");
 		goto error;
diff --git a/net/rds/tcp_connect.c b/net/rds/tcp_connect.c
index f0c477c5d1db4..5cf227472272e 100644
--- a/net/rds/tcp_connect.c
+++ b/net/rds/tcp_connect.c
@@ -145,7 +145,7 @@ int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
 		addrlen = sizeof(sin);
 	}
 
-	ret = sock->ops->bind(sock, addr, addrlen);
+	ret = kernel_bind(sock, addr, addrlen);
 	if (ret) {
 		rdsdebug("bind failed with %d at address %pI6c\n",
 			 ret, &conn->c_laddr);
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index 014fa24418c12..53b3535a1e4a8 100644
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -306,7 +306,7 @@ struct socket *rds_tcp_listen_init(struct net *net, bool isv6)
 		addr_len = sizeof(*sin);
 	}
 
-	ret = sock->ops->bind(sock, (struct sockaddr *)&ss, addr_len);
+	ret = kernel_bind(sock, (struct sockaddr *)&ss, addr_len);
 	if (ret < 0) {
 		rdsdebug("could not bind %s listener socket: %d\n",
 			 isv6 ? "IPv6" : "IPv4", ret);
diff --git a/net/socket.c b/net/socket.c
index b5639a6500158..9bbc061688d28 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -3450,7 +3450,11 @@ static long compat_sock_ioctl(struct file *file, unsigned int cmd,
 
 int kernel_bind(struct socket *sock, struct sockaddr *addr, int addrlen)
 {
-	return sock->ops->bind(sock, addr, addrlen);
+	struct sockaddr_storage address;
+
+	memcpy(&address, addr, addrlen);
+
+	return sock->ops->bind(sock, (struct sockaddr *)&address, addrlen);
 }
 EXPORT_SYMBOL(kernel_bind);
 
-- 
2.42.0.609.gbb76f46606-goog

Re: [PATCH] net: prevent address rewrite in kernel_bind()

[Greg KH]

On Wed, Oct 11, 2023 at 03:28:50PM -0500, Jordan Rife wrote:
> commit c889a99a21bf124c3db08d09df919f0eccc5ea4c upstream.
> 
> Fix merge conflicts, so this patch can be backported to 4.19+.

Now queued up, thanks.

greg k-h