diff src/mail/ngx_mail_handler.c @ 290:f745bf973510 NGINX_0_5_15

nginx 0.5.15 *) Feature: the mail proxy supports authenticated SMTP proxying and the "smtp_auth", "smtp_capablities", and "xclient" directives. Thanks to Anton Yuzhaninov and Maxim Dounin. *) Feature: now the keep-alive connections are closed just after receiving the reconfiguration signal. *) Change: the "imap" and "auth" directives were renamed to the "mail" and "pop3_auth" directives. *) Bugfix: a segmentation fault occurred in worker process if the CRAM-MD5 authentication method was used and the APOP method was disabled. *) Bugfix: if the "starttls only" directive was used in POP3 protocol, then nginx allowed authentication without switching to the SSL mode. *) Bugfix: worker processes did not exit after reconfiguration and did not rotate logs if the eventport method was used. *) Bugfix: a worker process may got caught in an endless loop, if the "ip_hash" directive was used. *) Bugfix: now nginx does not log some alerts if eventport or /dev/poll methods are used.
author Igor Sysoev <http://sysoev.ru>
date Mon, 19 Mar 2007 00:00:00 +0300
parents
children 2ceaee987f37
line wrap: on
line diff
new file mode 100644
--- /dev/null
+++ b/src/mail/ngx_mail_handler.c
@@ -0,0 +1,1838 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+#include <ngx_mail.h>
+
+
+static void ngx_mail_init_session(ngx_connection_t *c);
+static void ngx_mail_init_protocol(ngx_event_t *rev);
+static ngx_int_t ngx_mail_decode_auth_plain(ngx_mail_session_t *s,
+    ngx_str_t *encoded);
+static void ngx_mail_do_auth(ngx_mail_session_t *s);
+static ngx_int_t ngx_mail_read_command(ngx_mail_session_t *s);
+static u_char *ngx_mail_log_error(ngx_log_t *log, u_char *buf, size_t len);
+
+#if (NGX_MAIL_SSL)
+static void ngx_mail_ssl_init_connection(ngx_ssl_t *ssl, ngx_connection_t *c);
+static void ngx_mail_ssl_handshake_handler(ngx_connection_t *c);
+#endif
+
+
+static ngx_str_t  greetings[] = {
+   ngx_string("+OK POP3 ready" CRLF),
+   ngx_string("* OK IMAP4 ready" CRLF)
+   /* SMTP greeting */
+};
+
+static ngx_str_t  internal_server_errors[] = {
+   ngx_string("-ERR internal server error" CRLF),
+   ngx_string("* BAD internal server error" CRLF),
+   ngx_string("451 4.3.2 Internal server error" CRLF),
+};
+
+static u_char  pop3_ok[] = "+OK" CRLF;
+static u_char  pop3_next[] = "+ " CRLF;
+static u_char  pop3_username[] = "+ VXNlcm5hbWU6" CRLF;
+static u_char  pop3_password[] = "+ UGFzc3dvcmQ6" CRLF;
+static u_char  pop3_invalid_command[] = "-ERR invalid command" CRLF;
+
+static u_char  imap_star[] = "* ";
+static u_char  imap_ok[] = "OK completed" CRLF;
+static u_char  imap_next[] = "+ OK" CRLF;
+static u_char  imap_bye[] = "* BYE" CRLF;
+static u_char  imap_invalid_command[] = "BAD invalid command" CRLF;
+
+static u_char  smtp_ok[] = "250 2.0.0 OK" CRLF;
+static u_char  smtp_bye[] = "221 2.0.0 Bye" CRLF;
+static u_char  smtp_next[] = "334 " CRLF;
+static u_char  smtp_username[] = "334 VXNlcm5hbWU6" CRLF;
+static u_char  smtp_password[] = "334 UGFzc3dvcmQ6" CRLF;
+static u_char  smtp_invalid_command[] = "500 5.5.1 Invalid command" CRLF;
+static u_char  smtp_invalid_argument[] = "501 5.5.4 Invalid argument" CRLF;
+static u_char  smtp_auth_required[] = "530 5.7.1 Authentication required" CRLF;
+
+
+void
+ngx_mail_init_connection(ngx_connection_t *c)
+{
+    in_addr_t             in_addr;
+    socklen_t             len;
+    ngx_uint_t            i;
+    struct sockaddr_in    sin;
+    ngx_mail_log_ctx_t   *ctx;
+    ngx_mail_in_port_t   *imip;
+    ngx_mail_in_addr_t   *imia;
+    ngx_mail_session_t   *s;
+#if (NGX_MAIL_SSL)
+    ngx_mail_ssl_conf_t  *sslcf;
+#endif
+
+
+    /* find the server configuration for the address:port */
+
+    /* AF_INET only */
+
+    imip = c->listening->servers;
+    imia = imip->addrs;
+
+    i = 0;
+
+    if (imip->naddrs > 1) {
+
+        /*
+         * There are several addresses on this port and one of them
+         * is the "*:port" wildcard so getsockname() is needed to determine
+         * the server address.
+         *
+         * AcceptEx() already gave this address.
+         */
+
+#if (NGX_WIN32)
+        if (c->local_sockaddr) {
+            in_addr =
+                   ((struct sockaddr_in *) c->local_sockaddr)->sin_addr.s_addr;
+
+        } else
+#endif
+        {
+            len = sizeof(struct sockaddr_in);
+            if (getsockname(c->fd, (struct sockaddr *) &sin, &len) == -1) {
+                ngx_connection_error(c, ngx_socket_errno,
+                                     "getsockname() failed");
+                ngx_mail_close_connection(c);
+                return;
+            }
+
+            in_addr = sin.sin_addr.s_addr;
+        }
+
+        /* the last address is "*" */
+
+        for ( /* void */ ; i < imip->naddrs - 1; i++) {
+            if (in_addr == imia[i].addr) {
+                break;
+            }
+        }
+    }
+
+
+    s = ngx_pcalloc(c->pool, sizeof(ngx_mail_session_t));
+    if (s == NULL) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    s->main_conf = imia[i].ctx->main_conf;
+    s->srv_conf = imia[i].ctx->srv_conf;
+
+    s->addr_text = &imia[i].addr_text;
+
+    c->data = s;
+    s->connection = c;
+
+    ngx_log_error(NGX_LOG_INFO, c->log, 0, "*%ui client %V connected to %V",
+                  c->number, &c->addr_text, s->addr_text);
+
+    ctx = ngx_palloc(c->pool, sizeof(ngx_mail_log_ctx_t));
+    if (ctx == NULL) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    ctx->client = &c->addr_text;
+    ctx->session = s;
+
+    c->log->connection = c->number;
+    c->log->handler = ngx_mail_log_error;
+    c->log->data = ctx;
+    c->log->action = "sending client greeting line";
+
+    c->log_error = NGX_ERROR_INFO;
+
+#if (NGX_MAIL_SSL)
+
+    sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
+
+    if (sslcf->enable) {
+        ngx_mail_ssl_init_connection(&sslcf->ssl, c);
+        return;
+    }
+
+#endif
+
+    ngx_mail_init_session(c);
+}
+
+
+#if (NGX_MAIL_SSL)
+
+static void
+ngx_mail_starttls_handler(ngx_event_t *rev)
+{
+    ngx_connection_t     *c;
+    ngx_mail_session_t   *s;
+    ngx_mail_ssl_conf_t  *sslcf;
+
+    c = rev->data;
+    s = c->data;
+    s->starttls = 1;
+
+    c->log->action = "in starttls state";
+
+    sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
+
+    ngx_mail_ssl_init_connection(&sslcf->ssl, c);
+}
+
+
+static void
+ngx_mail_ssl_init_connection(ngx_ssl_t *ssl, ngx_connection_t *c)
+{
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+
+    if (ngx_ssl_create_connection(ssl, c, 0) == NGX_ERROR) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    if (ngx_ssl_handshake(c) == NGX_AGAIN) {
+
+        s = c->data;
+
+        cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+        ngx_add_timer(c->read, cscf->timeout);
+
+        c->ssl->handler = ngx_mail_ssl_handshake_handler;
+
+        return;
+    }
+
+    ngx_mail_ssl_handshake_handler(c);
+}
+
+
+static void
+ngx_mail_ssl_handshake_handler(ngx_connection_t *c)
+{
+    ngx_mail_session_t  *s;
+
+    if (c->ssl->handshaked) {
+
+        s = c->data;
+
+        if (s->starttls) {
+            c->read->handler = ngx_mail_init_protocol;
+            c->write->handler = ngx_mail_send;
+
+            ngx_mail_init_protocol(c->read);
+
+            return;
+        }
+
+        ngx_mail_init_session(c);
+        return;
+    }
+
+    ngx_mail_close_connection(c);
+}
+
+#endif
+
+
+static void
+ngx_mail_init_session(ngx_connection_t *c)
+{
+    u_char                    *p;
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+
+    c->read->handler = ngx_mail_init_protocol;
+    c->write->handler = ngx_mail_send;
+
+    s = c->data;
+
+    cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+    s->protocol = cscf->protocol;
+
+    s->ctx = ngx_pcalloc(c->pool, sizeof(void *) * ngx_mail_max_module);
+    if (s->ctx == NULL) {
+        ngx_mail_session_internal_server_error(s);
+        return;
+    }
+
+    if (s->protocol == NGX_MAIL_SMTP_PROTOCOL) {
+        s->out = cscf->smtp_greeting;
+
+    } else {
+        s->out = greetings[s->protocol];
+    }
+
+    if ((s->protocol == NGX_MAIL_POP3_PROTOCOL
+         && (cscf->pop3_auth_methods
+             & (NGX_MAIL_AUTH_APOP_ENABLED|NGX_MAIL_AUTH_CRAM_MD5_ENABLED)))
+
+        || (s->protocol == NGX_MAIL_SMTP_PROTOCOL
+           && (cscf->smtp_auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED)))
+    {
+        s->salt.data = ngx_palloc(c->pool,
+                                 sizeof(" <18446744073709551616.@>" CRLF) - 1
+                                 + NGX_TIME_T_LEN
+                                 + cscf->server_name.len);
+        if (s->salt.data == NULL) {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+
+        s->salt.len = ngx_sprintf(s->salt.data, "<%ul.%T@%V>" CRLF,
+                                  ngx_random(), ngx_time(), &cscf->server_name)
+                     - s->salt.data;
+
+        if (s->protocol == NGX_MAIL_POP3_PROTOCOL) {
+	    s->out.data = ngx_palloc(c->pool,
+                                     greetings[0].len + 1 + s->salt.len);
+	    if (s->out.data == NULL) {
+		ngx_mail_session_internal_server_error(s);
+		return;
+	    }
+
+	    p = ngx_cpymem(s->out.data,
+                           greetings[0].data, greetings[0].len - 2);
+	    *p++ = ' ';
+	    p = ngx_cpymem(p, s->salt.data, s->salt.len);
+
+	    s->out.len = p - s->out.data;
+        }
+    }
+
+    ngx_add_timer(c->read, cscf->timeout);
+
+    if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) {
+        ngx_mail_close_connection(c);
+    }
+
+    ngx_mail_send(c->write);
+}
+
+
+void
+ngx_mail_send(ngx_event_t *wev)
+{
+    ngx_int_t                  n;
+    ngx_connection_t          *c;
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+
+    c = wev->data;
+    s = c->data;
+
+    if (wev->timedout) {
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
+        c->timedout = 1;
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    if (s->out.len == 0) {
+        if (ngx_handle_write_event(c->write, 0) == NGX_ERROR) {
+            ngx_mail_close_connection(c);
+        }
+
+        return;
+    }
+
+    n = c->send(c, s->out.data, s->out.len);
+
+    if (n > 0) {
+        s->out.len -= n;
+
+        if (wev->timer_set) {
+            ngx_del_timer(wev);
+        }
+
+        if (s->quit) {
+            ngx_mail_close_connection(c);
+            return;
+        }
+
+        if (s->blocked) {
+            c->read->handler(c->read);
+        }
+
+        return;
+    }
+
+    if (n == NGX_ERROR) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    /* n == NGX_AGAIN */
+
+    cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+    ngx_add_timer(c->write, cscf->timeout);
+
+    if (ngx_handle_write_event(c->write, 0) == NGX_ERROR) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+}
+
+
+static void
+ngx_mail_init_protocol(ngx_event_t *rev)
+{
+    size_t                     size;
+    ngx_connection_t          *c;
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+
+    c = rev->data;
+
+    c->log->action = "in auth state";
+
+    if (rev->timedout) {
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
+        c->timedout = 1;
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    s = c->data;
+
+    switch (s->protocol) {
+
+    case NGX_MAIL_POP3_PROTOCOL:
+        size = 128;
+        s->mail_state = ngx_pop3_start;
+        c->read->handler = ngx_pop3_auth_state;
+        break;
+
+    case NGX_MAIL_IMAP_PROTOCOL:
+        cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+        size = cscf->imap_client_buffer_size;
+        s->mail_state = ngx_imap_start;
+        c->read->handler = ngx_imap_auth_state;
+        break;
+
+    default: /* NGX_MAIL_SMTP_PROTOCOL */
+        size = 512;
+        s->mail_state = ngx_smtp_start;
+        c->read->handler = ngx_smtp_auth_state;
+        break;
+    }
+
+    if (s->buffer == NULL) {
+        if (ngx_array_init(&s->args, c->pool, 2, sizeof(ngx_str_t))
+            == NGX_ERROR)
+        {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+
+        s->buffer = ngx_create_temp_buf(c->pool, size);
+        if (s->buffer == NULL) {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+    }
+
+    c->read->handler(rev);
+}
+
+
+void
+ngx_pop3_auth_state(ngx_event_t *rev)
+{
+    u_char                    *p, *last, *text;
+    ssize_t                    size;
+    ngx_int_t                  rc;
+    ngx_str_t                 *arg, salt;
+    ngx_connection_t          *c;
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+#if (NGX_MAIL_SSL)
+    ngx_mail_ssl_conf_t       *sslcf;
+#endif
+
+    c = rev->data;
+    s = c->data;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "pop3 auth state");
+
+    if (rev->timedout) {
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
+        c->timedout = 1;
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    if (s->out.len) {
+        ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "pop3 send handler busy");
+        s->blocked = 1;
+        return;
+    }
+
+    s->blocked = 0;
+
+    rc = ngx_mail_read_command(s);
+
+    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
+        return;
+    }
+
+    text = pop3_ok;
+    size = sizeof(pop3_ok) - 1;
+
+    if (rc == NGX_OK) {
+        switch (s->mail_state) {
+
+        case ngx_pop3_start:
+
+            switch (s->command) {
+
+            case NGX_POP3_USER:
+
+#if (NGX_MAIL_SSL)
+
+                if (c->ssl == NULL) {
+                    sslcf = ngx_mail_get_module_srv_conf(s,
+                                                         ngx_mail_ssl_module);
+
+                    if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
+                        rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                        break;
+                    }
+                }
+#endif
+
+                if (s->args.nelts == 1) {
+                    s->mail_state = ngx_pop3_user;
+
+                    arg = s->args.elts;
+                    s->login.len = arg[0].len;
+                    s->login.data = ngx_palloc(c->pool, s->login.len);
+                    if (s->login.data == NULL) {
+                        ngx_mail_session_internal_server_error(s);
+                        return;
+                    }
+
+                    ngx_memcpy(s->login.data, arg[0].data, s->login.len);
+
+                    ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                                   "pop3 login: \"%V\"", &s->login);
+
+                    break;
+                }
+
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+
+            case NGX_POP3_CAPA:
+                cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+#if (NGX_MAIL_SSL)
+
+                if (c->ssl == NULL) {
+                    sslcf = ngx_mail_get_module_srv_conf(s,
+                                                         ngx_mail_ssl_module);
+
+                    if (sslcf->starttls == NGX_MAIL_STARTTLS_ON) {
+                        size = cscf->pop3_starttls_capability.len;
+                        text = cscf->pop3_starttls_capability.data;
+                        break;
+                    }
+
+                    if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
+                        size = cscf->pop3_starttls_only_capability.len;
+                        text = cscf->pop3_starttls_only_capability.data;
+                        break;
+                    }
+                }
+#endif
+
+                size = cscf->pop3_capability.len;
+                text = cscf->pop3_capability.data;
+                break;
+
+            case NGX_POP3_APOP:
+
+#if (NGX_MAIL_SSL)
+
+                if (c->ssl == NULL) {
+                    sslcf = ngx_mail_get_module_srv_conf(s,
+                                                         ngx_mail_ssl_module);
+
+                    if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
+                        rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                        break;
+                    }
+                }
+#endif
+
+                cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+                if ((cscf->pop3_auth_methods & NGX_MAIL_AUTH_APOP_ENABLED)
+                    && s->args.nelts == 2)
+                {
+                    arg = s->args.elts;
+
+                    s->login.len = arg[0].len;
+                    s->login.data = ngx_palloc(c->pool, s->login.len);
+                    if (s->login.data == NULL) {
+                        ngx_mail_session_internal_server_error(s);
+                        return;
+                    }
+
+                    ngx_memcpy(s->login.data, arg[0].data, s->login.len);
+
+                    s->passwd.len = arg[1].len;
+                    s->passwd.data = ngx_palloc(c->pool, s->passwd.len);
+                    if (s->passwd.data == NULL) {
+                        ngx_mail_session_internal_server_error(s);
+                        return;
+                    }
+
+                    ngx_memcpy(s->passwd.data, arg[1].data, s->passwd.len);
+
+                    ngx_log_debug2(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                                   "pop3 apop: \"%V\" \"%V\"",
+                                   &s->login, &s->passwd);
+
+                    s->auth_method = NGX_MAIL_AUTH_APOP;
+
+                    ngx_mail_do_auth(s);
+                    return;
+                }
+
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+
+            case NGX_POP3_AUTH:
+
+#if (NGX_MAIL_SSL)
+
+                if (c->ssl == NULL) {
+                    sslcf = ngx_mail_get_module_srv_conf(s,
+                                                         ngx_mail_ssl_module);
+
+                    if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
+                        rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                        break;
+                    }
+                }
+#endif
+
+                cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+                if (s->args.nelts == 0) {
+                    size = cscf->pop3_auth_capability.len;
+                    text = cscf->pop3_auth_capability.data;
+                    s->state = 0;
+                    break;
+                }
+
+                arg = s->args.elts;
+
+                if (arg[0].len == 5) {
+
+                    if (ngx_strncasecmp(arg[0].data, (u_char *) "LOGIN", 5)
+                        == 0)
+                    {
+
+                        if (s->args.nelts != 1) {
+                            rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                            break;
+                        }
+
+                        s->mail_state = ngx_pop3_auth_login_username;
+
+                        size = sizeof(pop3_username) - 1;
+                        text = pop3_username;
+
+                        break;
+
+                    } else if (ngx_strncasecmp(arg[0].data, (u_char *) "PLAIN",
+                                               5)
+                               == 0)
+                    {
+
+                        if (s->args.nelts == 1) {
+                            s->mail_state = ngx_pop3_auth_plain;
+
+                            size = sizeof(pop3_next) - 1;
+                            text = pop3_next;
+
+                            break;
+                        }
+
+                        if (s->args.nelts == 2) {
+
+                            /*
+                             * workaround for Eudora for Mac: it sends
+                             *    AUTH PLAIN [base64 encoded]
+                             */
+
+                            rc = ngx_mail_decode_auth_plain(s, &arg[1]);
+
+                            if (rc == NGX_OK) {
+                                ngx_mail_do_auth(s);
+                                return;
+                            }
+
+                            if (rc == NGX_ERROR) {
+                                ngx_mail_session_internal_server_error(s);
+                                return;
+                            }
+
+                            /* rc == NGX_MAIL_PARSE_INVALID_COMMAND */
+
+                            break;
+                        }
+
+                        rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                        break;
+                    }
+
+                } else if (arg[0].len == 8
+                           && ngx_strncasecmp(arg[0].data,
+                                              (u_char *) "CRAM-MD5", 8)
+                              == 0)
+                {
+                    if (s->args.nelts != 1) {
+                        rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                        break;
+                    }
+
+                    s->mail_state = ngx_pop3_auth_cram_md5;
+
+                    text = ngx_palloc(c->pool,
+                                      sizeof("+ " CRLF) - 1
+                                      + ngx_base64_encoded_length(s->salt.len));
+                    if (text == NULL) {
+                        ngx_mail_session_internal_server_error(s);
+                        return;
+                    }
+
+                    text[0] = '+'; text[1]= ' ';
+                    salt.data = &text[2];
+                    s->salt.len -= 2;
+
+                    ngx_encode_base64(&salt, &s->salt);
+
+                    s->salt.len += 2;
+                    size = 2 + salt.len;
+                    text[size++] = CR; text[size++] = LF;
+
+                    break;
+                }
+
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+
+            case NGX_POP3_QUIT:
+                s->quit = 1;
+                break;
+
+            case NGX_POP3_NOOP:
+                break;
+
+#if (NGX_MAIL_SSL)
+
+            case NGX_POP3_STLS:
+                if (c->ssl == NULL) {
+                    sslcf = ngx_mail_get_module_srv_conf(s,
+                                                         ngx_mail_ssl_module);
+                    if (sslcf->starttls) {
+                        c->read->handler = ngx_mail_starttls_handler;
+                        break;
+                    }
+                }
+
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+#endif
+
+            default:
+                s->mail_state = ngx_pop3_start;
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            break;
+
+        case ngx_pop3_user:
+
+            switch (s->command) {
+
+            case NGX_POP3_PASS:
+                if (s->args.nelts == 1) {
+                    arg = s->args.elts;
+                    s->passwd.len = arg[0].len;
+                    s->passwd.data = ngx_palloc(c->pool, s->passwd.len);
+                    if (s->passwd.data == NULL) {
+                        ngx_mail_session_internal_server_error(s);
+                        return;
+                    }
+
+                    ngx_memcpy(s->passwd.data, arg[0].data, s->passwd.len);
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+                    ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                                   "pop3 passwd: \"%V\"", &s->passwd);
+#endif
+
+                    ngx_mail_do_auth(s);
+                    return;
+                }
+
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+
+            case NGX_POP3_CAPA:
+                cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+                size = cscf->pop3_capability.len;
+                text = cscf->pop3_capability.data;
+                break;
+
+            case NGX_POP3_QUIT:
+                s->quit = 1;
+                break;
+
+            case NGX_POP3_NOOP:
+                break;
+
+            default:
+                s->mail_state = ngx_pop3_start;
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            break;
+
+        /* suppress warinings */
+        case ngx_pop3_passwd:
+            break;
+
+        case ngx_pop3_auth_login_username:
+            arg = s->args.elts;
+            s->mail_state = ngx_pop3_auth_login_password;
+
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "pop3 auth login username: \"%V\"", &arg[0]);
+
+            s->login.data = ngx_palloc(c->pool,
+                                       ngx_base64_decoded_length(arg[0].len));
+            if (s->login.data == NULL){
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            if (ngx_decode_base64(&s->login, &arg[0]) != NGX_OK) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid base64 encoding "
+                              "in AUTH LOGIN command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "pop3 auth login username: \"%V\"", &s->login);
+
+            size = sizeof(pop3_password) - 1;
+            text = pop3_password;
+
+            break;
+
+        case ngx_pop3_auth_login_password:
+            arg = s->args.elts;
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "pop3 auth login password: \"%V\"", &arg[0]);
+#endif
+
+            s->passwd.data = ngx_palloc(c->pool,
+                                        ngx_base64_decoded_length(arg[0].len));
+            if (s->passwd.data == NULL){
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            if (ngx_decode_base64(&s->passwd, &arg[0]) != NGX_OK) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid base64 encoding "
+                              "in AUTH LOGIN command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "pop3 auth login password: \"%V\"", &s->passwd);
+#endif
+
+            ngx_mail_do_auth(s);
+            return;
+
+        case ngx_pop3_auth_plain:
+            arg = s->args.elts;
+
+            rc = ngx_mail_decode_auth_plain(s, &arg[0]);
+
+            if (rc == NGX_OK) {
+                ngx_mail_do_auth(s);
+                return;
+            }
+
+            if (rc == NGX_ERROR) {
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            /* rc == NGX_MAIL_PARSE_INVALID_COMMAND */
+
+            break;
+
+        case ngx_pop3_auth_cram_md5:
+            arg = s->args.elts;
+
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "pop3 auth cram-md5: \"%V\"", &arg[0]);
+
+            s->login.data = ngx_palloc(c->pool,
+                                       ngx_base64_decoded_length(arg[0].len));
+            if (s->login.data == NULL){
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            if (ngx_decode_base64(&s->login, &arg[0]) != NGX_OK) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid base64 encoding "
+                              "in AUTH CRAM-MD5 command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            p = s->login.data;
+            last = p + s->login.len;
+
+            while (p < last) {
+                if (*p++ == ' ') {
+                    s->login.len = p - s->login.data - 1;
+                    s->passwd.len = last - p;
+                    s->passwd.data = p;
+                    break;
+                }
+            }
+
+            if (s->passwd.len != 32) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid CRAM-MD5 hash "
+                              "in AUTH CRAM-MD5 command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            ngx_log_debug2(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "pop3 auth cram-md5: \"%V\" \"%V\"",
+                           &s->login, &s->passwd);
+
+            s->auth_method = NGX_MAIL_AUTH_CRAM_MD5;
+
+            ngx_mail_do_auth(s);
+            return;
+        }
+    }
+
+    if (rc == NGX_MAIL_PARSE_INVALID_COMMAND) {
+        s->mail_state = ngx_pop3_start;
+        s->state = 0;
+        text = pop3_invalid_command;
+        size = sizeof(pop3_invalid_command) - 1;
+    }
+
+    s->args.nelts = 0;
+    s->buffer->pos = s->buffer->start;
+    s->buffer->last = s->buffer->start;
+
+    if (s->state) {
+        s->arg_start = s->buffer->start;
+    }
+
+    s->out.data = text;
+    s->out.len = size;
+
+    ngx_mail_send(c->write);
+}
+
+
+void
+ngx_imap_auth_state(ngx_event_t *rev)
+{
+    u_char                    *p, *last, *text, *dst, *src, *end;
+    ssize_t                    text_len, last_len;
+    ngx_str_t                 *arg;
+    ngx_int_t                  rc;
+    ngx_uint_t                 tag, i;
+    ngx_connection_t          *c;
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+#if (NGX_MAIL_SSL)
+    ngx_mail_ssl_conf_t       *sslcf;
+#endif
+
+    c = rev->data;
+    s = c->data;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap auth state");
+
+    if (rev->timedout) {
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
+        c->timedout = 1;
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    if (s->out.len) {
+        ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap send handler busy");
+        s->blocked = 1;
+        return;
+    }
+
+    s->blocked = 0;
+
+    rc = ngx_mail_read_command(s);
+
+    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
+        return;
+    }
+
+    tag = 1;
+
+    text = NULL;
+    text_len = 0;
+
+    last = imap_ok;
+    last_len = sizeof(imap_ok) - 1;
+
+    if (rc == NGX_OK) {
+
+        ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap auth command: %i",
+                       s->command);
+
+        if (s->backslash) {
+
+            arg = s->args.elts;
+
+            for (i = 0; i < s->args.nelts; i++) {
+                dst = arg[i].data;
+                end = dst + arg[i].len;
+
+                for (src = dst; src < end; dst++) {
+                    *dst = *src;
+                    if (*src++ == '\\') {
+                        *dst = *src++;
+                    }
+                }
+
+                arg[i].len = dst - arg[i].data;
+            }
+
+            s->backslash = 0;
+        }
+
+        switch (s->command) {
+
+        case NGX_IMAP_LOGIN:
+
+#if (NGX_MAIL_SSL)
+
+            if (c->ssl == NULL) {
+                sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
+
+                if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
+                    rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                    break;
+                }
+            }
+#endif
+
+            arg = s->args.elts;
+
+            if (s->args.nelts == 2 && arg[0].len) {
+
+                s->login.len = arg[0].len;
+                s->login.data = ngx_palloc(c->pool, s->login.len);
+                if (s->login.data == NULL) {
+                    ngx_mail_session_internal_server_error(s);
+                    return;
+                }
+
+                ngx_memcpy(s->login.data, arg[0].data, s->login.len);
+
+                s->passwd.len = arg[1].len;
+                s->passwd.data = ngx_palloc(c->pool, s->passwd.len);
+                if (s->passwd.data == NULL) {
+                    ngx_mail_session_internal_server_error(s);
+                    return;
+                }
+
+                ngx_memcpy(s->passwd.data, arg[1].data, s->passwd.len);
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+                ngx_log_debug2(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                               "imap login:\"%V\" passwd:\"%V\"",
+                               &s->login, &s->passwd);
+#else
+                ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                               "imap login:\"%V\"", &s->login);
+#endif
+
+                ngx_mail_do_auth(s);
+                return;
+            }
+
+            rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+            break;
+
+        case NGX_IMAP_CAPABILITY:
+            cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+#if (NGX_MAIL_SSL)
+
+            if (c->ssl == NULL) {
+                sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
+
+                if (sslcf->starttls == NGX_MAIL_STARTTLS_ON) {
+                    text_len = cscf->imap_starttls_capability.len;
+                    text = cscf->imap_starttls_capability.data;
+                    break;
+                }
+
+                if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
+                    text_len = cscf->imap_starttls_only_capability.len;
+                    text = cscf->imap_starttls_only_capability.data;
+                    break;
+                }
+            }
+#endif
+
+            text_len = cscf->imap_capability.len;
+            text = cscf->imap_capability.data;
+            break;
+
+        case NGX_IMAP_LOGOUT:
+            s->quit = 1;
+            text = imap_bye;
+            text_len = sizeof(imap_bye) - 1;
+            break;
+
+        case NGX_IMAP_NOOP:
+            break;
+
+#if (NGX_MAIL_SSL)
+
+        case NGX_IMAP_STARTTLS:
+            if (c->ssl == NULL) {
+                sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
+                if (sslcf->starttls) {
+                    c->read->handler = ngx_mail_starttls_handler;
+                    break;
+                }
+            }
+
+            rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+            break;
+#endif
+
+        default:
+            rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+            break;
+        }
+
+    } else if (rc == NGX_IMAP_NEXT) {
+        last = imap_next;
+        last_len = sizeof(imap_next) - 1;
+        tag = 0;
+    }
+
+    if (rc == NGX_MAIL_PARSE_INVALID_COMMAND) {
+        last = imap_invalid_command;
+        last_len = sizeof(imap_invalid_command) - 1;
+    }
+
+    if (tag) {
+        if (s->tag.len == 0) {
+            s->tag.len = sizeof(imap_star) - 1;
+            s->tag.data = (u_char *) imap_star;
+        }
+
+        if (s->tagged_line.len < s->tag.len + text_len + last_len) {
+            s->tagged_line.len = s->tag.len + text_len + last_len;
+            s->tagged_line.data = ngx_palloc(c->pool, s->tagged_line.len);
+            if (s->tagged_line.data == NULL) {
+                ngx_mail_close_connection(c);
+                return;
+            }
+        }
+
+        s->out.data = s->tagged_line.data;
+        s->out.len = s->tag.len + text_len + last_len;
+
+        p = s->out.data;
+
+        if (text) {
+            p = ngx_cpymem(p, text, text_len);
+        }
+        p = ngx_cpymem(p, s->tag.data, s->tag.len);
+        ngx_memcpy(p, last, last_len);
+
+
+    } else {
+        s->out.data = last;
+        s->out.len = last_len;
+    }
+
+    if (rc != NGX_IMAP_NEXT) {
+        s->args.nelts = 0;
+        s->buffer->pos = s->buffer->start;
+        s->buffer->last = s->buffer->start;
+        s->tag.len = 0;
+    }
+
+    ngx_mail_send(c->write);
+}
+
+
+void
+ngx_smtp_auth_state(ngx_event_t *rev)
+{
+    u_char                    *p, *last, *text, ch;
+    ssize_t                    size;
+    ngx_int_t                  rc;
+    ngx_str_t                 *arg, salt, l;
+    ngx_uint_t                 i;
+    ngx_connection_t          *c;
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+
+    c = rev->data;
+    s = c->data;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "smtp auth state");
+
+    if (rev->timedout) {
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
+        c->timedout = 1;
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    if (s->out.len) {
+        ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "smtp send handler busy");
+        s->blocked = 1;
+        return;
+    }
+
+    s->blocked = 0;
+
+    rc = ngx_mail_read_command(s);
+
+    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
+        return;
+    }
+
+    text = NULL;
+    size = 0;
+
+    if (rc == NGX_OK) {
+        switch (s->mail_state) {
+
+        case ngx_smtp_start:
+
+            switch (s->command) {
+
+            case NGX_SMTP_HELO:
+            case NGX_SMTP_EHLO:
+                cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+
+                if (s->args.nelts != 1) {
+                    text = smtp_invalid_argument;
+                    size = sizeof(smtp_invalid_argument) - 1;
+                    s->state = 0;
+                    break;
+                }
+
+                arg = s->args.elts;
+
+                s->smtp_helo.len = arg[0].len;
+
+                s->smtp_helo.data = ngx_palloc(c->pool, arg[0].len);
+                if (s->smtp_helo.data == NULL) {
+                    ngx_mail_session_internal_server_error(s);
+                    return;
+                }
+
+                ngx_memcpy(s->smtp_helo.data, arg[0].data, arg[0].len);
+
+                if (s->command == NGX_SMTP_HELO) {
+                    size = cscf->smtp_server_name.len;
+                    text = cscf->smtp_server_name.data;
+
+                } else {
+                    s->esmtp = 1;
+                    size = cscf->smtp_capability.len;
+                    text = cscf->smtp_capability.data;
+                }
+
+                break;
+
+            case NGX_SMTP_AUTH:
+
+                if (s->args.nelts == 0) {
+                    text = smtp_invalid_argument;
+                    size = sizeof(smtp_invalid_argument) - 1;
+                    s->state = 0;
+                    break;
+                }
+
+                arg = s->args.elts;
+
+                if (arg[0].len == 5) {
+
+                    if (ngx_strncasecmp(arg[0].data, (u_char *) "LOGIN", 5)
+                        == 0)
+                    {
+
+                        if (s->args.nelts != 1) {
+                            rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                            break;
+                        }
+
+                        s->mail_state = ngx_smtp_auth_login_username;
+
+                        size = sizeof(smtp_username) - 1;
+                        text = smtp_username;
+
+                        break;
+
+                    } else if (ngx_strncasecmp(arg[0].data, (u_char *) "PLAIN",
+                                               5)
+                               == 0)
+                    {
+                        if (s->args.nelts == 1) {
+                            s->mail_state = ngx_smtp_auth_plain;
+
+                            size = sizeof(smtp_next) - 1;
+                            text = smtp_next;
+
+                            break;
+                        }
+
+                        if (s->args.nelts == 2) {
+
+                            rc = ngx_mail_decode_auth_plain(s, &arg[1]);
+
+                            if (rc == NGX_OK) {
+                                ngx_mail_do_auth(s);
+                                return;
+                            }
+
+                            if (rc == NGX_ERROR) {
+                                ngx_mail_session_internal_server_error(s);
+                                return;
+                            }
+
+                            /* rc == NGX_MAIL_PARSE_INVALID_COMMAND */
+
+                            break;
+                        }
+
+                        rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                        break;
+                    }
+
+                } else if (arg[0].len == 8
+                           && ngx_strncasecmp(arg[0].data,
+                                              (u_char *) "CRAM-MD5", 8)
+                              == 0)
+                {
+                    if (s->args.nelts != 1) {
+                        rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                        break;
+                    }
+
+                    s->mail_state = ngx_smtp_auth_cram_md5;
+
+                    text = ngx_palloc(c->pool,
+                                      sizeof("334 " CRLF) - 1
+                                      + ngx_base64_encoded_length(s->salt.len));
+                    if (text == NULL) {
+                        ngx_mail_session_internal_server_error(s);
+                        return;
+                    }
+
+                    text[0] = '3'; text[1]= '3'; text[2] = '4'; text[3]= ' ';
+                    salt.data = &text[4];
+                    s->salt.len -= 2;
+
+                    ngx_encode_base64(&salt, &s->salt);
+
+                    s->salt.len += 2;
+                    size = 4 + salt.len;
+                    text[size++] = CR; text[size++] = LF;
+
+                    break;
+                }
+
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+
+            case NGX_SMTP_QUIT:
+                s->quit = 1;
+                text = smtp_bye;
+                size = sizeof(smtp_bye) - 1;
+                break;
+
+            case NGX_SMTP_MAIL:
+
+                if (s->connection->log->log_level >= NGX_LOG_INFO) {
+		    l.len = s->buffer->last - s->buffer->start;
+		    l.data = s->buffer->start;
+
+		    for (i = 0; i < l.len; i++) {
+			ch = l.data[i];
+
+			if (ch != CR && ch != LF) {
+			    continue;
+			}
+
+			l.data[i] = ' ';
+		    }
+
+		    while (i) {
+			if (l.data[i - 1] != ' ') {
+			    break;
+			}
+
+			i--;
+		    }
+
+		    l.len = i;
+
+		    ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
+				  "client was rejected: \"%V\"", &l);
+                }
+
+                text = smtp_auth_required;
+                size = sizeof(smtp_auth_required) - 1;
+                break;
+
+            case NGX_SMTP_NOOP:
+            case NGX_SMTP_RSET:
+                text = smtp_ok;
+                size = sizeof(smtp_ok) - 1;
+                break;
+            }
+
+            break;
+
+        case ngx_smtp_auth_login_username:
+            arg = s->args.elts;
+            s->mail_state = ngx_smtp_auth_login_password;
+
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "smtp auth login username: \"%V\"", &arg[0]);
+
+            s->login.data = ngx_palloc(c->pool,
+                                       ngx_base64_decoded_length(arg[0].len));
+            if (s->login.data == NULL){
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            if (ngx_decode_base64(&s->login, &arg[0]) != NGX_OK) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid base64 encoding "
+                              "in AUTH LOGIN command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "smtp auth login username: \"%V\"", &s->login);
+
+            size = sizeof(smtp_password) - 1;
+            text = smtp_password;
+
+            break;
+
+        case ngx_smtp_auth_login_password:
+            arg = s->args.elts;
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "smtp auth login password: \"%V\"", &arg[0]);
+#endif
+
+            s->passwd.data = ngx_palloc(c->pool,
+                                        ngx_base64_decoded_length(arg[0].len));
+            if (s->passwd.data == NULL){
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            if (ngx_decode_base64(&s->passwd, &arg[0]) != NGX_OK) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid base64 encoding "
+                              "in AUTH LOGIN command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "smtp auth login password: \"%V\"", &s->passwd);
+#endif
+
+            ngx_mail_do_auth(s);
+            return;
+
+        case ngx_smtp_auth_plain:
+            arg = s->args.elts;
+
+            rc = ngx_mail_decode_auth_plain(s, &arg[0]);
+
+            if (rc == NGX_OK) {
+                ngx_mail_do_auth(s);
+                return;
+            }
+
+            if (rc == NGX_ERROR) {
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            /* rc == NGX_MAIL_PARSE_INVALID_COMMAND */
+
+            break;
+
+        case ngx_smtp_auth_cram_md5:
+            arg = s->args.elts;
+
+            ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "smtp auth cram-md5: \"%V\"", &arg[0]);
+
+            s->login.data = ngx_palloc(c->pool,
+                                       ngx_base64_decoded_length(arg[0].len));
+            if (s->login.data == NULL){
+                ngx_mail_session_internal_server_error(s);
+                return;
+            }
+
+            if (ngx_decode_base64(&s->login, &arg[0]) != NGX_OK) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid base64 encoding "
+                              "in AUTH CRAM-MD5 command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            p = s->login.data;
+            last = p + s->login.len;
+
+            while (p < last) {
+                if (*p++ == ' ') {
+                    s->login.len = p - s->login.data - 1;
+                    s->passwd.len = last - p;
+                    s->passwd.data = p;
+                    break;
+                }
+            }
+
+            if (s->passwd.len != 32) {
+                ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                              "client sent invalid CRAM-MD5 hash "
+                              "in AUTH CRAM-MD5 command");
+                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
+                break;
+            }
+
+            ngx_log_debug2(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                           "smtp auth cram-md5: \"%V\" \"%V\"",
+                           &s->login, &s->passwd);
+
+            s->auth_method = NGX_MAIL_AUTH_CRAM_MD5;
+
+            ngx_mail_do_auth(s);
+            return;
+        }
+    }
+
+    if (rc == NGX_MAIL_PARSE_INVALID_COMMAND) {
+        s->mail_state = ngx_smtp_start;
+        s->state = 0;
+        text = smtp_invalid_command;
+        size = sizeof(smtp_invalid_command) - 1;
+    }
+
+    s->args.nelts = 0;
+    s->buffer->pos = s->buffer->start;
+    s->buffer->last = s->buffer->start;
+
+    if (s->state) {
+        s->arg_start = s->buffer->start;
+    }
+
+    s->out.data = text;
+    s->out.len = size;
+
+    ngx_mail_send(c->write);
+}
+
+
+static ngx_int_t
+ngx_mail_decode_auth_plain(ngx_mail_session_t *s, ngx_str_t *encoded)
+{
+    u_char     *p, *last;
+    ngx_str_t   plain;
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+    ngx_log_debug1(NGX_LOG_DEBUG_MAIL, s->connection->log, 0,
+                   "mail auth plain: \"%V\"", encoded);
+#endif
+
+    plain.data = ngx_palloc(s->connection->pool,
+                            ngx_base64_decoded_length(encoded->len));
+    if (plain.data == NULL){
+        return NGX_ERROR;
+    }
+
+    if (ngx_decode_base64(&plain, encoded) != NGX_OK) {
+        ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
+                      "client sent invalid base64 encoding "
+                      "in AUTH PLAIN command");
+        return NGX_MAIL_PARSE_INVALID_COMMAND;
+    }
+
+    p = plain.data;
+    last = p + plain.len;
+
+    while (p < last && *p++) { /* void */ }
+
+    if (p == last) {
+        ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
+                      "client sent invalid login in AUTH PLAIN command");
+        return NGX_MAIL_PARSE_INVALID_COMMAND;
+    }
+
+    s->login.data = p;
+
+    while (p < last && *p) { p++; }
+
+    if (p == last) {
+        ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
+                      "client sent invalid password in AUTH PLAIN command");
+        return NGX_MAIL_PARSE_INVALID_COMMAND;
+    }
+
+    s->login.len = p++ - s->login.data;
+
+    s->passwd.len = last - p;
+    s->passwd.data = p;
+
+#if (NGX_DEBUG_MAIL_PASSWD)
+    ngx_log_debug2(NGX_LOG_DEBUG_MAIL, s->connection->log, 0,
+                   "mail auth plain: \"%V\" \"%V\"",
+                   &s->login, &s->passwd);
+#endif
+
+    return NGX_OK;
+}
+
+
+static void
+ngx_mail_do_auth(ngx_mail_session_t *s)
+{
+    s->args.nelts = 0;
+    s->buffer->pos = s->buffer->start;
+    s->buffer->last = s->buffer->start;
+    s->state = 0;
+
+    if (s->connection->read->timer_set) {
+        ngx_del_timer(s->connection->read);
+    }
+
+    s->login_attempt++;
+
+    ngx_mail_auth_http_init(s);
+}
+
+
+static ngx_int_t
+ngx_mail_read_command(ngx_mail_session_t *s)
+{
+    ssize_t    n;
+    ngx_int_t  rc;
+    ngx_str_t  l;
+
+    n = s->connection->recv(s->connection, s->buffer->last,
+                            s->buffer->end - s->buffer->last);
+
+    if (n == NGX_ERROR || n == 0) {
+        ngx_mail_close_connection(s->connection);
+        return NGX_ERROR;
+    }
+
+    if (n > 0) {
+        s->buffer->last += n;
+    }
+
+    if (n == NGX_AGAIN) {
+        if (ngx_handle_read_event(s->connection->read, 0) == NGX_ERROR) {
+            ngx_mail_session_internal_server_error(s);
+            return NGX_ERROR;
+        }
+
+        return NGX_AGAIN;
+    }
+
+    switch (s->protocol) {
+    case NGX_MAIL_POP3_PROTOCOL:
+        rc = ngx_pop3_parse_command(s);
+        break;
+
+    case NGX_MAIL_IMAP_PROTOCOL:
+        rc = ngx_imap_parse_command(s);
+        break;
+
+    default: /* NGX_MAIL_SMTP_PROTOCOL */
+        rc = ngx_smtp_parse_command(s);
+        break;
+    }
+
+    if (rc == NGX_AGAIN) {
+
+        if (s->buffer->last < s->buffer->end) {
+            return rc;
+        }
+
+        l.len = s->buffer->last - s->buffer->start;
+        l.data = s->buffer->start;
+
+        ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
+                      "client sent too long command \"%V\"", &l);
+
+        s->quit = 1;
+
+        return NGX_MAIL_PARSE_INVALID_COMMAND;
+    }
+
+    if (rc == NGX_IMAP_NEXT || rc == NGX_MAIL_PARSE_INVALID_COMMAND) {
+        return rc;
+    }
+
+    if (rc == NGX_ERROR) {
+        ngx_mail_close_connection(s->connection);
+        return NGX_ERROR;
+    }
+
+    return NGX_OK;
+}
+
+
+void
+ngx_mail_session_internal_server_error(ngx_mail_session_t *s)
+{
+    s->out = internal_server_errors[s->protocol];
+    s->quit = 1;
+
+    ngx_mail_send(s->connection->write);
+}
+
+
+void
+ngx_mail_close_connection(ngx_connection_t *c)
+{
+    ngx_pool_t  *pool;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                   "close mail connection: %d", c->fd);
+
+#if (NGX_MAIL_SSL)
+
+    if (c->ssl) {
+        if (ngx_ssl_shutdown(c) == NGX_AGAIN) {
+            c->ssl->handler = ngx_mail_close_connection;
+            return;
+        }
+    }
+
+#endif
+
+    c->destroyed = 1;
+
+    pool = c->pool;
+
+    ngx_close_connection(c);
+
+    ngx_destroy_pool(pool);
+}
+
+
+static u_char *
+ngx_mail_log_error(ngx_log_t *log, u_char *buf, size_t len)
+{
+    u_char              *p;
+    ngx_mail_session_t  *s;
+    ngx_mail_log_ctx_t  *ctx;
+
+    if (log->action) {
+        p = ngx_snprintf(buf, len, " while %s", log->action);
+        len -= p - buf;
+        buf = p;
+    }
+
+    ctx = log->data;
+
+    p = ngx_snprintf(buf, len, ", client: %V", ctx->client);
+    len -= p - buf;
+    buf = p;
+
+    s = ctx->session;
+
+    if (s == NULL) {
+        return p;
+    }
+
+    p = ngx_snprintf(buf, len, ", server: %V", s->addr_text);
+    len -= p - buf;
+    buf = p;
+
+    if (s->login.len == 0) {
+        return p;
+    }
+
+    p = ngx_snprintf(buf, len, ", login: \"%V\"", &s->login);
+    len -= p - buf;
+    buf = p;
+
+    if (s->proxy == NULL) {
+        return p;
+    }
+
+    p = ngx_snprintf(buf, len, ", upstream: %V", s->proxy->upstream.name);
+
+    return p;
+}