389-ds-base/SOURCES/0001-Issue-3527-Support-HAProxy-and-Instance-on-the-same-.patch

From fcdeec3b876a28e06bb53a60fe502cb702403931 Mon Sep 17 00:00:00 2001
From: Simon Pichugin <spichugi@redhat.com>
Date: Tue, 27 Feb 2024 16:30:47 -0800
Subject: [PATCH] Issue 3527 - Support HAProxy and Instance on the same machine
 configuration (#6107)

Description: Improve how we handle HAProxy connections to work better when
the DS and HAProxy are on the same machine.
Ensure the client and header destination IPs are checked against the trusted IP list.

Additionally, this change will also allow configuration having
HAProxy is listening on a different subnet than the one used to forward the request.

Related: https://github.com/389ds/389-ds-base/issues/3527

Reviewed by: @progier389, @jchapma (Thanks!)
---
 ldap/servers/slapd/connection.c | 35 +++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/ldap/servers/slapd/connection.c b/ldap/servers/slapd/connection.c
index a30511c97..07d629475 100644
--- a/ldap/servers/slapd/connection.c
+++ b/ldap/servers/slapd/connection.c
@@ -1187,6 +1187,8 @@ connection_read_operation(Connection *conn, Operation *op, ber_tag_t *tag, int *
     char str_ip[INET6_ADDRSTRLEN + 1] = {0};
     char str_haproxy_ip[INET6_ADDRSTRLEN + 1] = {0};
     char str_haproxy_destip[INET6_ADDRSTRLEN + 1] = {0};
+    int trusted_matches_ip_found = 0;
+    int trusted_matches_destip_found = 0;
     struct berval **bvals = NULL;
     int proxy_connection = 0;
 
@@ -1245,21 +1247,38 @@ connection_read_operation(Connection *conn, Operation *op, ber_tag_t *tag, int *
                         normalize_IPv4(conn->cin_addr, buf_ip, sizeof(buf_ip), str_ip, sizeof(str_ip));
                         normalize_IPv4(&pr_netaddr_dest, buf_haproxy_destip, sizeof(buf_haproxy_destip),
                                        str_haproxy_destip, sizeof(str_haproxy_destip));
+                        size_t ip_len = strlen(buf_ip);
+                        size_t destip_len = strlen(buf_haproxy_destip);
 
                         /* Now, reset RC and set it to 0 only if a match is found */
                         haproxy_rc = -1;
 
-                        /* Allow only:
-                        * Trusted IP == Original Client IP == HAProxy Header Destination IP */
+                        /* 
+                         * We need to allow a configuration where DS instance and HAProxy are on the same machine.
+                         * In this case, we need to check if
+                         * the HAProxy client IP (which will be a loopback address) matches one of the the trusted IP addresses,
+                         * while still checking that
+                         * the HAProxy header destination IP address matches one of the trusted IP addresses.
+                         * Additionally, this change will also allow configuration having
+                         * HAProxy listening on a different subnet than one used to forward the request.
+                         */
                         for (size_t i = 0; bvals[i] != NULL; ++i) {
-                            if ((strlen(bvals[i]->bv_val) == strlen(buf_ip)) &&
-                                (strlen(bvals[i]->bv_val) == strlen(buf_haproxy_destip)) &&
-                                (strncasecmp(bvals[i]->bv_val, buf_ip, strlen(buf_ip)) == 0) &&
-                                (strncasecmp(bvals[i]->bv_val, buf_haproxy_destip, strlen(buf_haproxy_destip)) == 0)) {
-                                haproxy_rc = 0;
-                                break;
+                            size_t bval_len = strlen(bvals[i]->bv_val);
+
+                            /* Check if the Client IP (HAProxy's machine IP) address matches the trusted IP address */
+                            if (!trusted_matches_ip_found) {
+                                trusted_matches_ip_found = (bval_len == ip_len) && (strncasecmp(bvals[i]->bv_val, buf_ip, ip_len) == 0);
+                            }
+                            /* Check if the HAProxy header destination IP address matches the trusted IP address */
+                            if (!trusted_matches_destip_found) {
+                                trusted_matches_destip_found = (bval_len == destip_len) && (strncasecmp(bvals[i]->bv_val, buf_haproxy_destip, destip_len) == 0);
                             }
                         }
+
+                        if (trusted_matches_ip_found && trusted_matches_destip_found) {
+                            haproxy_rc = 0;
+                        }
+
                         if (haproxy_rc == -1) {
                             slapi_log_err(SLAPI_LOG_CONNS, "connection_read_operation", "HAProxy header received from unknown source.\n");
                             disconnect_server_nomutex(conn, conn->c_connid, -1, SLAPD_DISCONNECT_PROXY_UNKNOWN, EPROTO);
-- 
2.43.0