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From 6dafcdebde58577f4fcb190be46a0eb910cf1b96 Mon Sep 17 00:00:00 2001
From: Maxim Dounin <mdounin@mdounin.ru>
Date: Wed, 19 May 2021 03:13:31 +0300
Subject: [PATCH 1/1] Mail: max_errors directive.
Similarly to smtpd_hard_error_limit in Postfix and smtp_max_unknown_commands
in Exim, specifies the number of errors after which the connection is closed.
Index: nginx-1.16.1/src/mail/ngx_mail.h
===================================================================
--- nginx-1.16.1.orig/src/mail/ngx_mail.h
+++ nginx-1.16.1/src/mail/ngx_mail.h
@@ -113,6 +113,8 @@ typedef struct {
ngx_msec_t timeout;
ngx_msec_t resolver_timeout;
+ ngx_uint_t max_errors;
+
ngx_str_t server_name;
u_char *file_name;
@@ -225,6 +227,7 @@ typedef struct {
ngx_uint_t command;
ngx_array_t args;
+ ngx_uint_t errors;
ngx_uint_t login_attempt;
/* used to parse POP3/IMAP/SMTP command */
Index: nginx-1.16.1/src/mail/ngx_mail_core_module.c
===================================================================
--- nginx-1.16.1.orig/src/mail/ngx_mail_core_module.c
+++ nginx-1.16.1/src/mail/ngx_mail_core_module.c
@@ -85,6 +85,13 @@ static ngx_command_t ngx_mail_core_comm
offsetof(ngx_mail_core_srv_conf_t, resolver_timeout),
NULL },
+ { ngx_string("max_errors"),
+ NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
+ ngx_conf_set_num_slot,
+ NGX_MAIL_SRV_CONF_OFFSET,
+ offsetof(ngx_mail_core_srv_conf_t, max_errors),
+ NULL },
+
ngx_null_command
};
@@ -163,6 +170,8 @@ ngx_mail_core_create_srv_conf(ngx_conf_t
cscf->timeout = NGX_CONF_UNSET_MSEC;
cscf->resolver_timeout = NGX_CONF_UNSET_MSEC;
+ cscf->max_errors = NGX_CONF_UNSET_UINT;
+
cscf->resolver = NGX_CONF_UNSET_PTR;
cscf->file_name = cf->conf_file->file.name.data;
@@ -182,6 +191,7 @@ ngx_mail_core_merge_srv_conf(ngx_conf_t
ngx_conf_merge_msec_value(conf->resolver_timeout, prev->resolver_timeout,
30000);
+ ngx_conf_merge_uint_value(conf->max_errors, prev->max_errors, 5);
ngx_conf_merge_str_value(conf->server_name, prev->server_name, "");
Index: nginx-1.16.1/src/mail/ngx_mail_handler.c
===================================================================
--- nginx-1.16.1.orig/src/mail/ngx_mail_handler.c
+++ nginx-1.16.1/src/mail/ngx_mail_handler.c
@@ -753,7 +753,20 @@ ngx_mail_read_command(ngx_mail_session_t
return NGX_MAIL_PARSE_INVALID_COMMAND;
}
- if (rc == NGX_IMAP_NEXT || rc == NGX_MAIL_PARSE_INVALID_COMMAND) {
+ if (rc == NGX_MAIL_PARSE_INVALID_COMMAND) {
+
+ s->errors++;
+
+ if (s->errors >= cscf->max_errors) {
+ ngx_log_error(NGX_LOG_INFO, c->log, 0,
+ "client sent too many invalid commands");
+ s->quit = 1;
+ }
+
+ return rc;
+ }
+
+ if (rc == NGX_IMAP_NEXT) {
return rc;
}
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