From 07101d5a162a125232d992648a8598bfdeee3f3f Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Tue, 8 Sep 2015 16:16:35 +0200
Subject: [PATCH] BUG/MEDIUM: dns: use the correct server hostname when
 resolving

The server's host name picked for resolution was incorrect, it did not
skip the address family specifier, did not resolve environment variables,
and messed up with the optional trailing colon.

Instead, let's get the fqdn returned by str2sa_range() and use that
exclusively.
---
 src/server.c | 29 +++++++----------------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/src/server.c b/src/server.c
index 0e5c07999..f8fbe6a9a 100644
--- a/src/server.c
+++ b/src/server.c
@@ -835,6 +835,7 @@ int parse_server(const char *file, int linenum, char **args, struct proxy *curpr
 	char *errmsg = NULL;
 	int err_code = 0;
 	unsigned val;
+	char *fqdn = NULL;
 
 	if (!strcmp(args[0], "server") || !strcmp(args[0], "default-server")) {  /* server address */
 		int cur_arg;
@@ -904,7 +905,7 @@ int parse_server(const char *file, int linenum, char **args, struct proxy *curpr
 			 *  - IP:+N => port=+N, relative
 			 *  - IP:-N => port=-N, relative
 			 */
-			sk = str2sa_range(args[2], &port1, &port2, &errmsg, NULL, NULL);
+			sk = str2sa_range(args[2], &port1, &port2, &errmsg, NULL, &fqdn);
 			if (!sk) {
 				Alert("parsing [%s:%d] : '%s %s' : %s\n", file, linenum, args[0], args[1], errmsg);
 				err_code |= ERR_ALERT | ERR_FATAL;
@@ -936,29 +937,11 @@ int parse_server(const char *file, int linenum, char **args, struct proxy *curpr
 			}
 
 			/* save hostname and create associated name resolution */
-			switch (sk->ss_family) {
-			case AF_INET: {
-				/* remove the port if any */
-				char *c;
-				if ((c = rindex(args[2], ':')) != NULL) {
-					newsrv->hostname = my_strndup(args[2], c - args[2]);
-				}
-				else {
-					newsrv->hostname = strdup(args[2]);
-				}
-			}
-				break;
-			case AF_INET6:
-				newsrv->hostname = strdup(args[2]);
-				break;
-			default:
-				goto skip_name_resolution;
-			}
-
-			/* no name resolution if an IP has been provided */
-			if (inet_pton(sk->ss_family, newsrv->hostname, trash.str) == 1)
+			newsrv->hostname = fqdn;
+			if (!fqdn)
 				goto skip_name_resolution;
 
+			fqdn = NULL;
 			if ((curr_resolution = calloc(1, sizeof(struct dns_resolution))) == NULL)
 				goto skip_name_resolution;
 
@@ -1779,9 +1762,11 @@ int parse_server(const char *file, int linenum, char **args, struct proxy *curpr
 			srv_lb_commit_status(newsrv);
 		}
 	}
+	free(fqdn);
 	return 0;
 
  out:
+	free(fqdn);
 	free(errmsg);
 	return err_code;
 }