view src/mail/ngx_mail_pop3_handler.c @ 7152:3b635e8fd499

FastCGI: adjust buffer position when parsing incomplete records. Previously, nginx failed to move buffer position when parsing an incomplete record header, and due to this wasn't be able to continue parsing once remaining bytes of the record header were received. This can affect response header parsing, potentially generating spurious errors like "upstream sent unexpected FastCGI request id high byte: 1 while reading response header from upstream". While this is very unlikely, since usually record headers are written in a single buffer, this still can happen in real life, for example, if a record header will be split across two TCP packets and the second packet will be delayed. This does not affect non-buffered response body proxying, due to "buf->pos = buf->last;" at the start of the ngx_http_fastcgi_non_buffered_filter() function. Also this does not affect buffered response body proxying, as each input buffer is only passed to the filter once.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 09 Nov 2017 15:35:20 +0300
parents b2915d99ee8d
children ab6257dac2a8
line wrap: on
line source


/*
 * 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_pop3_module.h>


static ngx_int_t ngx_mail_pop3_user(ngx_mail_session_t *s, ngx_connection_t *c);
static ngx_int_t ngx_mail_pop3_pass(ngx_mail_session_t *s, ngx_connection_t *c);
static ngx_int_t ngx_mail_pop3_capa(ngx_mail_session_t *s, ngx_connection_t *c,
    ngx_int_t stls);
static ngx_int_t ngx_mail_pop3_stls(ngx_mail_session_t *s, ngx_connection_t *c);
static ngx_int_t ngx_mail_pop3_apop(ngx_mail_session_t *s, ngx_connection_t *c);
static ngx_int_t ngx_mail_pop3_auth(ngx_mail_session_t *s, ngx_connection_t *c);


static u_char  pop3_greeting[] = "+OK POP3 ready" 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;


void
ngx_mail_pop3_init_session(ngx_mail_session_t *s, ngx_connection_t *c)
{
    u_char                    *p;
    ngx_mail_core_srv_conf_t  *cscf;
    ngx_mail_pop3_srv_conf_t  *pscf;

    pscf = ngx_mail_get_module_srv_conf(s, ngx_mail_pop3_module);
    cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);

    if (pscf->auth_methods
        & (NGX_MAIL_AUTH_APOP_ENABLED|NGX_MAIL_AUTH_CRAM_MD5_ENABLED))
    {
        if (ngx_mail_salt(s, c, cscf) != NGX_OK) {
            ngx_mail_session_internal_server_error(s);
            return;
        }

        s->out.data = ngx_pnalloc(c->pool, sizeof(pop3_greeting) + s->salt.len);
        if (s->out.data == NULL) {
            ngx_mail_session_internal_server_error(s);
            return;
        }

        p = ngx_cpymem(s->out.data, pop3_greeting, sizeof(pop3_greeting) - 3);
        *p++ = ' ';
        p = ngx_cpymem(p, s->salt.data, s->salt.len);

        s->out.len = p - s->out.data;

    } else {
        ngx_str_set(&s->out, pop3_greeting);
    }

    c->read->handler = ngx_mail_pop3_init_protocol;

    ngx_add_timer(c->read, cscf->timeout);

    if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
        ngx_mail_close_connection(c);
    }

    ngx_mail_send(c->write);
}


void
ngx_mail_pop3_init_protocol(ngx_event_t *rev)
{
    ngx_connection_t    *c;
    ngx_mail_session_t  *s;

    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;

    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, 128);
        if (s->buffer == NULL) {
            ngx_mail_session_internal_server_error(s);
            return;
        }
    }

    s->mail_state = ngx_pop3_start;
    c->read->handler = ngx_mail_pop3_auth_state;

    ngx_mail_pop3_auth_state(rev);
}


void
ngx_mail_pop3_auth_state(ngx_event_t *rev)
{
    ngx_int_t            rc;
    ngx_connection_t    *c;
    ngx_mail_session_t  *s;

    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, c);

    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
        return;
    }

    ngx_str_set(&s->out, pop3_ok);

    if (rc == NGX_OK) {
        switch (s->mail_state) {

        case ngx_pop3_start:

            switch (s->command) {

            case NGX_POP3_USER:
                rc = ngx_mail_pop3_user(s, c);
                break;

            case NGX_POP3_CAPA:
                rc = ngx_mail_pop3_capa(s, c, 1);
                break;

            case NGX_POP3_APOP:
                rc = ngx_mail_pop3_apop(s, c);
                break;

            case NGX_POP3_AUTH:
                rc = ngx_mail_pop3_auth(s, c);
                break;

            case NGX_POP3_QUIT:
                s->quit = 1;
                break;

            case NGX_POP3_NOOP:
                break;

            case NGX_POP3_STLS:
                rc = ngx_mail_pop3_stls(s, c);
                break;

            default:
                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
                break;
            }

            break;

        case ngx_pop3_user:

            switch (s->command) {

            case NGX_POP3_PASS:
                rc = ngx_mail_pop3_pass(s, c);
                break;

            case NGX_POP3_CAPA:
                rc = ngx_mail_pop3_capa(s, c, 0);
                break;

            case NGX_POP3_QUIT:
                s->quit = 1;
                break;

            case NGX_POP3_NOOP:
                break;

            default:
                rc = NGX_MAIL_PARSE_INVALID_COMMAND;
                break;
            }

            break;

        /* suppress warnings */
        case ngx_pop3_passwd:
            break;

        case ngx_pop3_auth_login_username:
            rc = ngx_mail_auth_login_username(s, c, 0);

            ngx_str_set(&s->out, pop3_password);
            s->mail_state = ngx_pop3_auth_login_password;
            break;

        case ngx_pop3_auth_login_password:
            rc = ngx_mail_auth_login_password(s, c);
            break;

        case ngx_pop3_auth_plain:
            rc = ngx_mail_auth_plain(s, c, 0);
            break;

        case ngx_pop3_auth_cram_md5:
            rc = ngx_mail_auth_cram_md5(s, c);
            break;

        case ngx_pop3_auth_external:
            rc = ngx_mail_auth_external(s, c, 0);
            break;
        }
    }

    switch (rc) {

    case NGX_DONE:
        ngx_mail_auth(s, c);
        return;

    case NGX_ERROR:
        ngx_mail_session_internal_server_error(s);
        return;

    case NGX_MAIL_PARSE_INVALID_COMMAND:
        s->mail_state = ngx_pop3_start;
        s->state = 0;

        ngx_str_set(&s->out, pop3_invalid_command);

        /* fall through */

    case NGX_OK:

        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;
        }

        ngx_mail_send(c->write);
    }
}

static ngx_int_t
ngx_mail_pop3_user(ngx_mail_session_t *s, ngx_connection_t *c)
{
    ngx_str_t  *arg;

#if (NGX_MAIL_SSL)
    if (ngx_mail_starttls_only(s, c)) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }
#endif

    if (s->args.nelts != 1) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    arg = s->args.elts;
    s->login.len = arg[0].len;
    s->login.data = ngx_pnalloc(c->pool, s->login.len);
    if (s->login.data == NULL) {
        return NGX_ERROR;
    }

    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);

    s->mail_state = ngx_pop3_user;

    return NGX_OK;
}


static ngx_int_t
ngx_mail_pop3_pass(ngx_mail_session_t *s, ngx_connection_t *c)
{
    ngx_str_t  *arg;

    if (s->args.nelts != 1) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    arg = s->args.elts;
    s->passwd.len = arg[0].len;
    s->passwd.data = ngx_pnalloc(c->pool, s->passwd.len);
    if (s->passwd.data == NULL) {
        return NGX_ERROR;
    }

    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

    return NGX_DONE;
}


static ngx_int_t
ngx_mail_pop3_capa(ngx_mail_session_t *s, ngx_connection_t *c, ngx_int_t stls)
{
    ngx_mail_pop3_srv_conf_t  *pscf;

    pscf = ngx_mail_get_module_srv_conf(s, ngx_mail_pop3_module);

#if (NGX_MAIL_SSL)

    if (stls && c->ssl == NULL) {
        ngx_mail_ssl_conf_t  *sslcf;

        sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);

        if (sslcf->starttls == NGX_MAIL_STARTTLS_ON) {
            s->out = pscf->starttls_capability;
            return NGX_OK;
        }

        if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) {
            s->out = pscf->starttls_only_capability;
            return NGX_OK;
        }
    }

#endif

    s->out = pscf->capability;
    return NGX_OK;
}


static ngx_int_t
ngx_mail_pop3_stls(ngx_mail_session_t *s, ngx_connection_t *c)
{
#if (NGX_MAIL_SSL)
    ngx_mail_ssl_conf_t  *sslcf;

    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;
            return NGX_OK;
        }
    }

#endif

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}


static ngx_int_t
ngx_mail_pop3_apop(ngx_mail_session_t *s, ngx_connection_t *c)
{
    ngx_str_t                 *arg;
    ngx_mail_pop3_srv_conf_t  *pscf;

#if (NGX_MAIL_SSL)
    if (ngx_mail_starttls_only(s, c)) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }
#endif

    if (s->args.nelts != 2) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    pscf = ngx_mail_get_module_srv_conf(s, ngx_mail_pop3_module);

    if (!(pscf->auth_methods & NGX_MAIL_AUTH_APOP_ENABLED)) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    arg = s->args.elts;

    s->login.len = arg[0].len;
    s->login.data = ngx_pnalloc(c->pool, s->login.len);
    if (s->login.data == NULL) {
        return NGX_ERROR;
    }

    ngx_memcpy(s->login.data, arg[0].data, s->login.len);

    s->passwd.len = arg[1].len;
    s->passwd.data = ngx_pnalloc(c->pool, s->passwd.len);
    if (s->passwd.data == NULL) {
        return NGX_ERROR;
    }

    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;

    return NGX_DONE;
}


static ngx_int_t
ngx_mail_pop3_auth(ngx_mail_session_t *s, ngx_connection_t *c)
{
    ngx_int_t                  rc;
    ngx_mail_pop3_srv_conf_t  *pscf;

#if (NGX_MAIL_SSL)
    if (ngx_mail_starttls_only(s, c)) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }
#endif

    pscf = ngx_mail_get_module_srv_conf(s, ngx_mail_pop3_module);

    if (s->args.nelts == 0) {
        s->out = pscf->auth_capability;
        s->state = 0;

        return NGX_OK;
    }

    rc = ngx_mail_auth_parse(s, c);

    switch (rc) {

    case NGX_MAIL_AUTH_LOGIN:

        ngx_str_set(&s->out, pop3_username);
        s->mail_state = ngx_pop3_auth_login_username;

        return NGX_OK;

    case NGX_MAIL_AUTH_LOGIN_USERNAME:

        ngx_str_set(&s->out, pop3_password);
        s->mail_state = ngx_pop3_auth_login_password;

        return ngx_mail_auth_login_username(s, c, 1);

    case NGX_MAIL_AUTH_PLAIN:

        ngx_str_set(&s->out, pop3_next);
        s->mail_state = ngx_pop3_auth_plain;

        return NGX_OK;

    case NGX_MAIL_AUTH_CRAM_MD5:

        if (!(pscf->auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED)) {
            return NGX_MAIL_PARSE_INVALID_COMMAND;
        }

        if (ngx_mail_auth_cram_md5_salt(s, c, "+ ", 2) == NGX_OK) {
            s->mail_state = ngx_pop3_auth_cram_md5;
            return NGX_OK;
        }

        return NGX_ERROR;

    case NGX_MAIL_AUTH_EXTERNAL:

        if (!(pscf->auth_methods & NGX_MAIL_AUTH_EXTERNAL_ENABLED)) {
            return NGX_MAIL_PARSE_INVALID_COMMAND;
        }

        ngx_str_set(&s->out, pop3_username);
        s->mail_state = ngx_pop3_auth_external;

        return NGX_OK;
    }

    return rc;
}