[PATCH uhttpd 2/3] listen: Copy only parts of ai_addr

[Hauke Mehrtens]

ai_addr has different sizes for IPv4 and IPv6. Only copy the parts which
are actually used and not the full array, to not copy and uninitialized
memory.

This fixes a warning found with the address sanitizer.

Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 listen.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/listen.c b/listen.c
index 2a54888..558e35e 100644
--- a/listen.c
+++ b/listen.c
@@ -29,7 +29,10 @@ struct listener {
 	struct uloop_fd fd;
 	int socket;
 	int n_clients;
-	struct sockaddr_in6 addr;
+	union {
+		struct sockaddr_in6 addr6;
+		struct sockaddr_in addr;
+	};
 	bool tls;
 	bool blocked;
 };
@@ -189,7 +192,9 @@ int uh_socket_bind(const char *host, const char *port, bool tls)
 
 		l->fd.fd = sock;
 		l->tls = tls;
-		l->addr = *(struct sockaddr_in6 *)p->ai_addr;
+		if (p->ai_addrlen < sizeof(l->addr))
+			goto error;
+		memcpy(&l->addr, p->ai_addr, p->ai_addrlen);
 		list_add_tail(&l->list, &listeners);
 		bound++;
 
@@ -211,13 +216,13 @@ int uh_first_tls_port(int family)
 	int tls_port = -1;
 
 	list_for_each_entry(l, &listeners, list) {
-		if (!l->tls || l->addr.sin6_family != family)
+		if (!l->tls || l->addr.sin_family != family)
 			continue;
 
-		if (tls_port != -1 && ntohs(l->addr.sin6_port) != 443)
+		if (tls_port != -1 && ntohs(l->addr.sin_port) != 443)
 			continue;
 
-		tls_port = ntohs(l->addr.sin6_port);
+		tls_port = ntohs(l->addr.sin_port);
 	}
 
 	return tls_port;
-- 
2.20.1