netdev - [PATCH net v5 3/3] net: prevent address rewrite in kernel

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Date: Thu, 21 Sep 2023 18:46:42 -0500
From: Jordan Rife <jrife@...gle.com>
To: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org, 
	pabeni@...hat.com, willemdebruijn.kernel@...il.com, netdev@...r.kernel.org
Cc: dborkman@...nel.org, horms@...ge.net.au, pablo@...filter.org, 
	kadlec@...filter.org, fw@...len.de, santosh.shilimkar@...cle.com, 
	ast@...nel.org, rdna@...com, Jordan Rife <jrife@...gle.com>, stable@...r.kernel.org, 
	Willem de Bruijn <willemb@...gle.com>
Subject: [PATCH net v5 3/3] net: prevent address rewrite in kernel_bind()

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@...r.kernel.org
Reviewed-by: Willem de Bruijn <willemb@...gle.com>
Signed-off-by: Jordan Rife <jrife@...gle.com>
---
v4->v5: Remove non-net changes.
v3->v4: Remove precondition check for addrlen. Pass address copy to
        bind() instead of original address.
v2->v3: Add "Fixes" tag. Check for positivity in addrlen sanity check.
v1->v2: Split up original patch into patch series. Insulate
        sock->ops->bind() calls with kernel_bind().

 net/netfilter/ipvs/ip_vs_sync.c | 4 ++--
 net/rds/tcp_connect.c           | 2 +-
 net/rds/tcp_listen.c            | 2 +-
 net/socket.c                    | 7 ++++++-
 4 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 6e4ed1e11a3b7..4174076c66fa7 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -1439,7 +1439,7 @@ 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,
@@ -1546,7 +1546,7 @@ 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 d788c6d28986f..a0046e99d6df7 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 a39ec136f5cff..c4a6f55329552 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -3516,7 +3516,12 @@ static long compat_sock_ioctl(struct file *file, unsigned int cmd,
 
 int kernel_bind(struct socket *sock, struct sockaddr *addr, int addrlen)
 {
-	return READ_ONCE(sock->ops)->bind(sock, addr, addrlen);
+	struct sockaddr_storage address;
+
+	memcpy(&address, addr, addrlen);
+
+	return READ_ONCE(sock->ops)->bind(sock, (struct sockaddr *)&address,
+					  addrlen);
 }
 EXPORT_SYMBOL(kernel_bind);
 
-- 
2.42.0.515.g380fc7ccd1-goog