changeset 7725:d63c5373b5ba

Mail: proxy_smtp_auth directive. The proxy_smtp_auth directive instructs nginx to authenticate users on backend via the AUTH command (using the PLAIN SASL mechanism), similar to what is normally done for IMAP and POP3. If xclient is enabled along with proxy_smtp_auth, the XCLIENT command won't try to send the LOGIN parameter.
author Maxim Dounin <mdounin@mdounin.ru>
date Sat, 03 Oct 2020 21:04:57 +0300
parents 64b97c8166b8
children 559d19037984
files src/mail/ngx_mail.h src/mail/ngx_mail_proxy_module.c
diffstat 2 files changed, 87 insertions(+), 4 deletions(-) [+]
line wrap: on
line diff
--- a/src/mail/ngx_mail.h
+++ b/src/mail/ngx_mail.h
@@ -162,10 +162,12 @@ typedef enum {
     ngx_smtp_auth_external,
     ngx_smtp_helo,
     ngx_smtp_helo_xclient,
+    ngx_smtp_helo_auth,
     ngx_smtp_helo_from,
     ngx_smtp_xclient,
     ngx_smtp_xclient_from,
     ngx_smtp_xclient_helo,
+    ngx_smtp_xclient_auth,
     ngx_smtp_from,
     ngx_smtp_to
 } ngx_smtp_state_e;
--- a/src/mail/ngx_mail_proxy_module.c
+++ b/src/mail/ngx_mail_proxy_module.c
@@ -16,6 +16,7 @@ typedef struct {
     ngx_flag_t  enable;
     ngx_flag_t  pass_error_message;
     ngx_flag_t  xclient;
+    ngx_flag_t  smtp_auth;
     size_t      buffer_size;
     ngx_msec_t  timeout;
 } ngx_mail_proxy_conf_t;
@@ -74,6 +75,13 @@ static ngx_command_t  ngx_mail_proxy_com
       offsetof(ngx_mail_proxy_conf_t, xclient),
       NULL },
 
+    { ngx_string("proxy_smtp_auth"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_proxy_conf_t, smtp_auth),
+      NULL },
+
       ngx_null_command
 };
 
@@ -450,7 +458,7 @@ ngx_mail_proxy_smtp_handler(ngx_event_t 
 {
     u_char                    *p;
     ngx_int_t                  rc;
-    ngx_str_t                  line;
+    ngx_str_t                  line, auth, encoded;
     ngx_buf_t                 *b;
     ngx_connection_t          *c;
     ngx_mail_session_t        *s;
@@ -513,6 +521,9 @@ ngx_mail_proxy_smtp_handler(ngx_event_t 
         } else if (s->auth_method == NGX_MAIL_AUTH_NONE) {
             s->mail_state = ngx_smtp_helo_from;
 
+        } else if (pcf->smtp_auth) {
+            s->mail_state = ngx_smtp_helo_auth;
+
         } else {
             s->mail_state = ngx_smtp_helo;
         }
@@ -552,7 +563,9 @@ ngx_mail_proxy_smtp_handler(ngx_event_t 
         p = ngx_copy(p, s->connection->addr_text.data,
                      s->connection->addr_text.len);
 
-        if (s->login.len) {
+        pcf = ngx_mail_get_module_srv_conf(s, ngx_mail_proxy_module);
+
+        if (s->login.len && !pcf->smtp_auth) {
             p = ngx_cpymem(p, " LOGIN=", sizeof(" LOGIN=") - 1);
             p = ngx_copy(p, s->login.data, s->login.len);
         }
@@ -570,6 +583,9 @@ ngx_mail_proxy_smtp_handler(ngx_event_t 
         } else if (s->auth_method == NGX_MAIL_AUTH_NONE) {
             s->mail_state = ngx_smtp_xclient_from;
 
+        } else if (pcf->smtp_auth) {
+            s->mail_state = ngx_smtp_xclient_auth;
+
         } else {
             s->mail_state = ngx_smtp_xclient;
         }
@@ -595,8 +611,62 @@ ngx_mail_proxy_smtp_handler(ngx_event_t 
                        &s->smtp_helo)
                    - line.data;
 
-        s->mail_state = (s->auth_method == NGX_MAIL_AUTH_NONE) ?
-                            ngx_smtp_helo_from : ngx_smtp_helo;
+        pcf = ngx_mail_get_module_srv_conf(s, ngx_mail_proxy_module);
+
+        if (s->auth_method == NGX_MAIL_AUTH_NONE) {
+            s->mail_state = ngx_smtp_helo_from;
+
+        } else if (pcf->smtp_auth) {
+            s->mail_state = ngx_smtp_helo_auth;
+
+        } else {
+            s->mail_state = ngx_smtp_helo;
+        }
+
+        break;
+
+    case ngx_smtp_helo_auth:
+    case ngx_smtp_xclient_auth:
+        ngx_log_debug0(NGX_LOG_DEBUG_MAIL, rev->log, 0,
+                       "mail proxy send auth");
+
+        s->connection->log->action = "sending AUTH to upstream";
+
+        if (s->passwd.data == NULL) {
+            ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
+                          "no password available");
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
+        auth.len = 1 + s->login.len + 1 + s->passwd.len;
+        auth.data = ngx_pnalloc(c->pool, auth.len);
+        if (auth.data == NULL) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
+        auth.len = ngx_sprintf(auth.data, "%Z%V%Z%V", &s->login, &s->passwd)
+                   - auth.data;
+
+        line.len = sizeof("AUTH PLAIN " CRLF) - 1
+                   + ngx_base64_encoded_length(auth.len);
+
+        line.data = ngx_pnalloc(c->pool, line.len);
+        if (line.data == NULL) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
+        encoded.data = ngx_cpymem(line.data, "AUTH PLAIN ",
+                                  sizeof("AUTH PLAIN ") - 1);
+
+        ngx_encode_base64(&encoded, &auth);
+
+        p = encoded.data + encoded.len;
+        *p++ = CR; *p = LF;
+
+        s->mail_state = ngx_smtp_auth_plain;
 
         break;
 
@@ -643,6 +713,7 @@ ngx_mail_proxy_smtp_handler(ngx_event_t 
 
     case ngx_smtp_helo:
     case ngx_smtp_xclient:
+    case ngx_smtp_auth_plain:
     case ngx_smtp_to:
 
         b = s->proxy->buffer;
@@ -824,6 +895,7 @@ ngx_mail_proxy_read_response(ngx_mail_se
         case ngx_smtp_helo:
         case ngx_smtp_helo_xclient:
         case ngx_smtp_helo_from:
+        case ngx_smtp_helo_auth:
         case ngx_smtp_from:
             if (p[0] == '2' && p[1] == '5' && p[2] == '0') {
                 return NGX_OK;
@@ -833,11 +905,18 @@ ngx_mail_proxy_read_response(ngx_mail_se
         case ngx_smtp_xclient:
         case ngx_smtp_xclient_from:
         case ngx_smtp_xclient_helo:
+        case ngx_smtp_xclient_auth:
             if (p[0] == '2' && (p[1] == '2' || p[1] == '5') && p[2] == '0') {
                 return NGX_OK;
             }
             break;
 
+        case ngx_smtp_auth_plain:
+            if (p[0] == '2' && p[1] == '3' && p[2] == '5') {
+                return NGX_OK;
+            }
+            break;
+
         case ngx_smtp_to:
             return NGX_OK;
         }
@@ -1102,6 +1181,7 @@ ngx_mail_proxy_create_conf(ngx_conf_t *c
     pcf->enable = NGX_CONF_UNSET;
     pcf->pass_error_message = NGX_CONF_UNSET;
     pcf->xclient = NGX_CONF_UNSET;
+    pcf->smtp_auth = NGX_CONF_UNSET;
     pcf->buffer_size = NGX_CONF_UNSET_SIZE;
     pcf->timeout = NGX_CONF_UNSET_MSEC;
 
@@ -1118,6 +1198,7 @@ ngx_mail_proxy_merge_conf(ngx_conf_t *cf
     ngx_conf_merge_value(conf->enable, prev->enable, 0);
     ngx_conf_merge_value(conf->pass_error_message, prev->pass_error_message, 0);
     ngx_conf_merge_value(conf->xclient, prev->xclient, 1);
+    ngx_conf_merge_value(conf->smtp_auth, prev->smtp_auth, 0);
     ngx_conf_merge_size_value(conf->buffer_size, prev->buffer_size,
                               (size_t) ngx_pagesize);
     ngx_conf_merge_msec_value(conf->timeout, prev->timeout, 24 * 60 * 60000);