BUG/MAJOR: fix listening IP address storage for frontends

When compiled with GCC 6, the IP address specified for a frontend was
ignored and HAProxy was listening on all addresses instead. This is
caused by an incomplete copy of a "struct sockaddr_storage".

With the GNU Libc, "struct sockaddr_storage" is defined as this:

    struct sockaddr_storage
      {
        sa_family_t ss_family;
        unsigned long int __ss_align;
        char __ss_padding[(128 - (2 * sizeof (unsigned long int)))];
      };

Doing an aggregate copy (ss1 = ss2) is different than using memcpy():
only members of the aggregate have to be copied. Notably, padding can be
or not be copied. In GCC 6, some optimizations use this fact and if a
"struct sockaddr_storage" contains a "struct sockaddr_in", the port and
the address are part of the padding (between sa_family and __ss_align)
and can be not copied over.

Therefore, we replace any aggregate copy by a memcpy(). There is another
place using the same pattern. We also fix a function receiving a "struct
sockaddr_storage" by copy instead of by reference. Since it only needs a
read-only copy, the function is converted to request a reference.

include/proto/proto_http.h

@@ -110,7 +110,7 @@ void http_set_status(unsigned int status, struct stream *s);
 int http_transform_header_str(struct stream* s, struct http_msg *msg, const char* name,
                               unsigned int name_len, const char *str, struct my_regex *re,
                               int action);
-void inet_set_tos(int fd, struct sockaddr_storage from, int tos);
+void inet_set_tos(int fd, const struct sockaddr_storage *from, int tos);
 void http_perform_server_redirect(struct stream *s, struct stream_interface *si);
 void http_return_srv_error(struct stream *s, struct stream_interface *si);
 void http_capture_bad_message(struct error_snapshot *es, struct stream *s,

src/cfgparse.c

@@ -287,7 +287,7 @@ int str2listener(char *str, struct proxy *curproxy, struct bind_conf *bind_conf,
 		}
 
 		/* OK the address looks correct */
-		ss = *ss2;
+		memcpy(&ss, ss2, sizeof(ss));
 
 		for (; port <= end; port++) {
 			l = calloc(1, sizeof(*l));

src/connection.c

@@ -744,7 +744,7 @@ int make_proxy_line_v2(char *buf, int buf_len, struct server *srv, struct connec
 	const char pp2_signature[] = PP2_SIGNATURE;
 	int ret = 0;
 	struct proxy_hdr_v2 *hdr = (struct proxy_hdr_v2 *)buf;
-	struct sockaddr_storage null_addr = {0};
+	struct sockaddr_storage null_addr = { .ss_family = 0 };
 	struct sockaddr_storage *src = &null_addr;
 	struct sockaddr_storage *dst = &null_addr;
 

src/hlua.c

@@ -4781,7 +4781,7 @@ __LJMP static int hlua_txn_set_tos(lua_State *L)
 	tos = MAY_LJMP(luaL_checkinteger(L, 2));
 
 	if ((cli_conn = objt_conn(htxn->s->sess->origin)) && conn_ctrl_ready(cli_conn))
-		inet_set_tos(cli_conn->t.sock.fd, cli_conn->addr.from, tos);
+		inet_set_tos(cli_conn->t.sock.fd, &cli_conn->addr.from, tos);
 
 	return 0;
 }

src/proto_http.c

@@ -3189,15 +3189,15 @@ int http_handle_stats(struct stream *s, struct channel *req)
 /* Sets the TOS header in IPv4 and the traffic class header in IPv6 packets
  * (as per RFC3260 #4 and BCP37 #4.2 and #5.2).
  */
-void inet_set_tos(int fd, struct sockaddr_storage from, int tos)
+void inet_set_tos(int fd, const struct sockaddr_storage *from, int tos)
 {
 #ifdef IP_TOS
-	if (from.ss_family == AF_INET)
+	if (from->ss_family == AF_INET)
 		setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
 #endif
 #ifdef IPV6_TCLASS
-	if (from.ss_family == AF_INET6) {
+	if (from->ss_family == AF_INET6) {
-		if (IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&from)->sin6_addr))
+		if (IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)from)->sin6_addr))
 			/* v4-mapped addresses need IP_TOS */
 			setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
 		else
@@ -3363,7 +3363,7 @@ resume_execution:
 
 		case ACT_HTTP_SET_TOS:
 			if ((cli_conn = objt_conn(sess->origin)) && conn_ctrl_ready(cli_conn))
-				inet_set_tos(cli_conn->t.sock.fd, cli_conn->addr.from, rule->arg.tos);
+				inet_set_tos(cli_conn->t.sock.fd, &cli_conn->addr.from, rule->arg.tos);
 			break;
 
 		case ACT_HTTP_SET_MARK:
@@ -3646,7 +3646,7 @@ resume_execution:
 
 		case ACT_HTTP_SET_TOS:
 			if ((cli_conn = objt_conn(sess->origin)) && conn_ctrl_ready(cli_conn))
-				inet_set_tos(cli_conn->t.sock.fd, cli_conn->addr.from, rule->arg.tos);
+				inet_set_tos(cli_conn->t.sock.fd, &cli_conn->addr.from, rule->arg.tos);
 			break;
 
 		case ACT_HTTP_SET_MARK:

src/proto_tcp.c

@@ -435,7 +435,7 @@ int tcp_connect_server(struct connection *conn, int data, int delack)
 			struct sockaddr_storage sa;
 
 			ret = 1;
-			sa = src->source_addr;
+			memcpy(&sa, &src->source_addr, sizeof(sa));
 
 			do {
 				/* note: in case of retry, we may have to release a previously