view src/mail/ngx_mail_smtp_module.c @ 8006:32b0ba4855a6

HTTP/2: made it possible to flush response headers (ticket #1743). Response headers can be buffered in the SSL buffer. But stream's fake connection buffered flag did not reflect this, so any attempts to flush the buffer without sending additional data were stopped by the write filter. It does not seem to be possible to reflect this in fc->buffered though, as we never known if main connection's c->buffered corresponds to the particular stream or not. As such, fc->buffered might prevent request finalization due to sending data on some other stream. Fix is to implement handling of flush buffers when the c->need_flush_buf flag is set, similarly to the existing last buffer handling. The same flag is now used for UDP sockets in the stream module instead of explicit checking of c->type.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 03 Feb 2022 01:44:38 +0300
parents dc955d274130
children 4538c1ffb0f8
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#include <ngx_mail.h>
#include <ngx_mail_smtp_module.h>


static void *ngx_mail_smtp_create_srv_conf(ngx_conf_t *cf);
static char *ngx_mail_smtp_merge_srv_conf(ngx_conf_t *cf, void *parent,
    void *child);


static ngx_conf_bitmask_t  ngx_mail_smtp_auth_methods[] = {
    { ngx_string("plain"), NGX_MAIL_AUTH_PLAIN_ENABLED },
    { ngx_string("login"), NGX_MAIL_AUTH_LOGIN_ENABLED },
    { ngx_string("cram-md5"), NGX_MAIL_AUTH_CRAM_MD5_ENABLED },
    { ngx_string("external"), NGX_MAIL_AUTH_EXTERNAL_ENABLED },
    { ngx_string("none"), NGX_MAIL_AUTH_NONE_ENABLED },
    { ngx_null_string, 0 }
};


static ngx_str_t  ngx_mail_smtp_auth_methods_names[] = {
    ngx_string("PLAIN"),
    ngx_string("LOGIN"),
    ngx_null_string,  /* APOP */
    ngx_string("CRAM-MD5"),
    ngx_string("EXTERNAL"),
    ngx_null_string   /* NONE */
};


static ngx_mail_protocol_t  ngx_mail_smtp_protocol = {
    ngx_string("smtp"),
    ngx_string("\x04smtp"),
    { 25, 465, 587, 0 },
    NGX_MAIL_SMTP_PROTOCOL,

    ngx_mail_smtp_init_session,
    ngx_mail_smtp_init_protocol,
    ngx_mail_smtp_parse_command,
    ngx_mail_smtp_auth_state,

    ngx_string("451 4.3.2 Internal server error" CRLF),
    ngx_string("421 4.7.1 SSL certificate error" CRLF),
    ngx_string("421 4.7.1 No required SSL certificate" CRLF)
};


static ngx_command_t  ngx_mail_smtp_commands[] = {

    { ngx_string("smtp_client_buffer"),
      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_MAIL_SRV_CONF_OFFSET,
      offsetof(ngx_mail_smtp_srv_conf_t, client_buffer_size),
      NULL },

    { ngx_string("smtp_greeting_delay"),
      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_MAIL_SRV_CONF_OFFSET,
      offsetof(ngx_mail_smtp_srv_conf_t, greeting_delay),
      NULL },

    { ngx_string("smtp_capabilities"),
      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE,
      ngx_mail_capabilities,
      NGX_MAIL_SRV_CONF_OFFSET,
      offsetof(ngx_mail_smtp_srv_conf_t, capabilities),
      NULL },

    { ngx_string("smtp_auth"),
      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_MAIL_SRV_CONF_OFFSET,
      offsetof(ngx_mail_smtp_srv_conf_t, auth_methods),
      &ngx_mail_smtp_auth_methods },

      ngx_null_command
};


static ngx_mail_module_t  ngx_mail_smtp_module_ctx = {
    &ngx_mail_smtp_protocol,               /* protocol */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    ngx_mail_smtp_create_srv_conf,         /* create server configuration */
    ngx_mail_smtp_merge_srv_conf           /* merge server configuration */
};


ngx_module_t  ngx_mail_smtp_module = {
    NGX_MODULE_V1,
    &ngx_mail_smtp_module_ctx,             /* module context */
    ngx_mail_smtp_commands,                /* module directives */
    NGX_MAIL_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static void *
ngx_mail_smtp_create_srv_conf(ngx_conf_t *cf)
{
    ngx_mail_smtp_srv_conf_t  *sscf;

    sscf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_smtp_srv_conf_t));
    if (sscf == NULL) {
        return NULL;
    }

    sscf->client_buffer_size = NGX_CONF_UNSET_SIZE;
    sscf->greeting_delay = NGX_CONF_UNSET_MSEC;

    if (ngx_array_init(&sscf->capabilities, cf->pool, 4, sizeof(ngx_str_t))
        != NGX_OK)
    {
        return NULL;
    }

    return sscf;
}


static char *
ngx_mail_smtp_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_mail_smtp_srv_conf_t *prev = parent;
    ngx_mail_smtp_srv_conf_t *conf = child;

    u_char                    *p, *auth, *last;
    size_t                     size;
    ngx_str_t                 *c;
    ngx_uint_t                 i, m, auth_enabled;
    ngx_mail_core_srv_conf_t  *cscf;

    ngx_conf_merge_size_value(conf->client_buffer_size,
                              prev->client_buffer_size,
                              (size_t) ngx_pagesize);

    ngx_conf_merge_msec_value(conf->greeting_delay,
                              prev->greeting_delay, 0);

    ngx_conf_merge_bitmask_value(conf->auth_methods,
                              prev->auth_methods,
                              (NGX_CONF_BITMASK_SET
                               |NGX_MAIL_AUTH_PLAIN_ENABLED
                               |NGX_MAIL_AUTH_LOGIN_ENABLED));


    cscf = ngx_mail_conf_get_module_srv_conf(cf, ngx_mail_core_module);

    size = sizeof("220  ESMTP ready" CRLF) - 1 + cscf->server_name.len;

    p = ngx_pnalloc(cf->pool, size);
    if (p == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->greeting.len = size;
    conf->greeting.data = p;

    *p++ = '2'; *p++ = '2'; *p++ = '0'; *p++ = ' ';
    p = ngx_cpymem(p, cscf->server_name.data, cscf->server_name.len);
    ngx_memcpy(p, " ESMTP ready" CRLF, sizeof(" ESMTP ready" CRLF) - 1);


    size = sizeof("250 " CRLF) - 1 + cscf->server_name.len;

    p = ngx_pnalloc(cf->pool, size);
    if (p == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->server_name.len = size;
    conf->server_name.data = p;

    *p++ = '2'; *p++ = '5'; *p++ = '0'; *p++ = ' ';
    p = ngx_cpymem(p, cscf->server_name.data, cscf->server_name.len);
    *p++ = CR; *p = LF;


    if (conf->capabilities.nelts == 0) {
        conf->capabilities = prev->capabilities;
    }

    size = sizeof("250-") - 1 + cscf->server_name.len + sizeof(CRLF) - 1;

    c = conf->capabilities.elts;
    for (i = 0; i < conf->capabilities.nelts; i++) {
        size += sizeof("250 ") - 1 + c[i].len + sizeof(CRLF) - 1;
    }

    auth_enabled = 0;

    for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0;
         m <= NGX_MAIL_AUTH_EXTERNAL_ENABLED;
         m <<= 1, i++)
    {
        if (m & conf->auth_methods) {
            size += 1 + ngx_mail_smtp_auth_methods_names[i].len;
            auth_enabled = 1;
        }
    }

    if (auth_enabled) {
        size += sizeof("250 AUTH") - 1 + sizeof(CRLF) - 1;
    }

    p = ngx_pnalloc(cf->pool, size);
    if (p == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->capability.len = size;
    conf->capability.data = p;

    last = p;

    *p++ = '2'; *p++ = '5'; *p++ = '0'; *p++ = '-';
    p = ngx_cpymem(p, cscf->server_name.data, cscf->server_name.len);
    *p++ = CR; *p++ = LF;

    for (i = 0; i < conf->capabilities.nelts; i++) {
        last = p;
        *p++ = '2'; *p++ = '5'; *p++ = '0'; *p++ = '-';
        p = ngx_cpymem(p, c[i].data, c[i].len);
        *p++ = CR; *p++ = LF;
    }

    auth = p;

    if (auth_enabled) {
        last = p;

        *p++ = '2'; *p++ = '5'; *p++ = '0'; *p++ = ' ';
        *p++ = 'A'; *p++ = 'U'; *p++ = 'T'; *p++ = 'H';

        for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0;
             m <= NGX_MAIL_AUTH_EXTERNAL_ENABLED;
             m <<= 1, i++)
        {
            if (m & conf->auth_methods) {
                *p++ = ' ';
                p = ngx_cpymem(p, ngx_mail_smtp_auth_methods_names[i].data,
                               ngx_mail_smtp_auth_methods_names[i].len);
            }
        }

        *p++ = CR; *p = LF;

    } else {
        last[3] = ' ';
    }

    size += sizeof("250 STARTTLS" CRLF) - 1;

    p = ngx_pnalloc(cf->pool, size);
    if (p == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->starttls_capability.len = size;
    conf->starttls_capability.data = p;

    p = ngx_cpymem(p, conf->capability.data, conf->capability.len);

    ngx_memcpy(p, "250 STARTTLS" CRLF, sizeof("250 STARTTLS" CRLF) - 1);

    p = conf->starttls_capability.data
        + (last - conf->capability.data) + 3;
    *p = '-';

    size = (auth - conf->capability.data)
            + sizeof("250 STARTTLS" CRLF) - 1;

    p = ngx_pnalloc(cf->pool, size);
    if (p == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->starttls_only_capability.len = size;
    conf->starttls_only_capability.data = p;

    p = ngx_cpymem(p, conf->capability.data, auth - conf->capability.data);

    ngx_memcpy(p, "250 STARTTLS" CRLF, sizeof("250 STARTTLS" CRLF) - 1);

    if (last < auth) {
        p = conf->starttls_only_capability.data
            + (last - conf->capability.data) + 3;
        *p = '-';
    }

    return NGX_CONF_OK;
}