bpf: Propagate modified uaddrlen from cgroup sockaddr programs

[ Upstream commit fefba7d1ae198dcbf8b3b432de46a4e29f8dbd8c ]

As prep for adding unix socket support to the cgroup sockaddr hooks,
let's propagate the sockaddr length back to the caller after running
a bpf cgroup sockaddr hook program. While not important for AF_INET or
AF_INET6, the sockaddr length is important when working with AF_UNIX
sockaddrs as the size of the sockaddr cannot be determined just from the
address family or the sockaddr's contents.

__cgroup_bpf_run_filter_sock_addr() is modified to take the uaddrlen as
an input/output argument. After running the program, the modified sockaddr
length is stored in the uaddrlen pointer.

Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-3-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Stable-dep-of: c5114710c8ce ("xsk: fix usage of multi-buffer BPF helpers for ZC XDP")
Signed-off-by: Sasha Levin <sashal@kernel.org>

4 files changed, 12 insertions, 8 deletions

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index b739ddbef0f0..7d4d625471f7 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -455,7 +455,7 @@ int inet_bind_sk(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	/* BPF prog is run before any checks are done so that if the prog
 	 * changes context in a wrong way it will be caught.
 	 */
-	err = BPF_CGROUP_RUN_PROG_INET_BIND_LOCK(sk, uaddr,
+	err = BPF_CGROUP_RUN_PROG_INET_BIND_LOCK(sk, uaddr, &addr_len,
 						 CGROUP_INET4_BIND, &flags);
 	if (err)
 		return err;
@@ -797,6 +797,7 @@ int inet_getname(struct socket *sock, struct sockaddr *uaddr,
 	struct sock *sk		= sock->sk;
 	struct inet_sock *inet	= inet_sk(sk);
 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, uaddr);
+	int sin_addr_len = sizeof(*sin);
 
 	sin->sin_family = AF_INET;
 	lock_sock(sk);
@@ -809,7 +810,7 @@ int inet_getname(struct socket *sock, struct sockaddr *uaddr,
 		}
 		sin->sin_port = inet->inet_dport;
 		sin->sin_addr.s_addr = inet->inet_daddr;
-		BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
+		BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin, &sin_addr_len,
 				       CGROUP_INET4_GETPEERNAME);
 	} else {
 		__be32 addr = inet->inet_rcv_saddr;
@@ -817,7 +818,7 @@ int inet_getname(struct socket *sock, struct sockaddr *uaddr,
 			addr = inet->inet_saddr;
 		sin->sin_port = inet->inet_sport;
 		sin->sin_addr.s_addr = addr;
-		BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
+		BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin, &sin_addr_len,
 				       CGROUP_INET4_GETSOCKNAME);
 	}
 	release_sock(sk);
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 75e0aee35eb7..4cb0c896caf9 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -301,7 +301,7 @@ static int ping_pre_connect(struct sock *sk, struct sockaddr *uaddr,
 	if (addr_len < sizeof(struct sockaddr_in))
 		return -EINVAL;
 
-	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
+	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr, &addr_len);
 }
 
 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 4167e8a48b60..c7ffab37a34c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -194,7 +194,7 @@ static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
 
 	sock_owned_by_me(sk);
 
-	return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
+	return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
 }
 
 /* This will initiate an outgoing connection. */
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 9cb22a6ae1dc..7be4ddc80d95 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1143,7 +1143,9 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	if (cgroup_bpf_enabled(CGROUP_UDP4_SENDMSG) && !connected) {
 		err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
-					    (struct sockaddr *)usin, &ipc.addr);
+					    (struct sockaddr *)usin,
+					    &msg->msg_namelen,
+					    &ipc.addr);
 		if (err)
 			goto out_free;
 		if (usin) {
@@ -1865,7 +1867,8 @@ try_again:
 		*addr_len = sizeof(*sin);
 
 		BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk,
-						      (struct sockaddr *)sin);
+						      (struct sockaddr *)sin,
+						      addr_len);
 	}
 
 	if (udp_test_bit(GRO_ENABLED, sk))
@@ -1904,7 +1907,7 @@ int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	if (addr_len < sizeof(struct sockaddr_in))
 		return -EINVAL;
 
-	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
+	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr, &addr_len);
 }
 EXPORT_SYMBOL(udp_pre_connect);