[PATCH 1/1] Return EINVAL if the user provides a return data structure for getsockname that is too small to hold the PF_ address. This introduces a new error code but this should be OK as the error is real and would otherwise corrupt the user-application's stack, i.e., it results in trouble no matter what. I do not do a partial copy of the sockaddr structure because it does not make very much sense to retrieve only part of the socket address (e.g., ip + af_family).

[John Reumann <reumann.linux@gmail.com>]

---
 net/ipv4/af_inet.c  |    7 +++++--
 net/ipv6/af_inet6.c |    3 +++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 743f554..52283ff 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -677,10 +677,13 @@ do_err:
 int inet_getname(struct socket *sock, struct sockaddr *uaddr,
 			int *uaddr_len, int peer)
 {
-	struct sock *sk		= sock->sk;
-	struct inet_sock *inet	= inet_sk(sk);
+	struct sock *sk = sock->sk;
+	struct inet_sock *inet = inet_sk(sk);
 	struct sockaddr_in *sin	= (struct sockaddr_in *)uaddr;
 
+	if (*uaddr_len < sizeof(struct sockaddr_in))
+		return -EINVAL;
+
 	sin->sin_family = AF_INET;
 	if (peer) {
 		if (!inet->dport ||
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index c802bc1..74b8407 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -401,6 +401,9 @@ int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
 	struct inet_sock *inet = inet_sk(sk);
 	struct ipv6_pinfo *np = inet6_sk(sk);
 
+	if (*uaddr_len < sizeof(struct sockaddr_in6))
+		return -EINVAL;
+
 	sin->sin6_family = AF_INET6;
 	sin->sin6_flowinfo = 0;
 	sin->sin6_scope_id = 0;
-- 
1.5.4.5