diff options
Diffstat (limited to 'src/mail/ngx_mail_smtp_handler.c')
| -rw-r--r-- | src/mail/ngx_mail_smtp_handler.c | 548 |
1 files changed, 548 insertions, 0 deletions
diff --git a/src/mail/ngx_mail_smtp_handler.c b/src/mail/ngx_mail_smtp_handler.c new file mode 100644 index 000000000..96cb762ed --- /dev/null +++ b/src/mail/ngx_mail_smtp_handler.c @@ -0,0 +1,548 @@ + +/* + * Copyright (C) Igor Sysoev + */ + + +#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_invalid_pipelining(ngx_event_t *rev); +static ngx_int_t ngx_mail_smtp_create_buffer(ngx_mail_session_t *s, + ngx_connection_t *c); + +static ngx_int_t ngx_mail_smtp_helo(ngx_mail_session_t *s, ngx_connection_t *c); +static ngx_int_t ngx_mail_smtp_auth(ngx_mail_session_t *s, ngx_connection_t *c); +static ngx_int_t ngx_mail_smtp_mail(ngx_mail_session_t *s, ngx_connection_t *c); +static ngx_int_t ngx_mail_smtp_starttls(ngx_mail_session_t *s, + ngx_connection_t *c); + +static ngx_int_t ngx_mail_smtp_discard_command(ngx_mail_session_t *s, + ngx_connection_t *c, char *err); +static void ngx_mail_smtp_log_rejected_command(ngx_mail_session_t *s, + ngx_connection_t *c, char *err); + + +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_pipelining[] = + "503 5.5.0 Improper use of SMTP command pipelining" 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_smtp_init_session(ngx_mail_session_t *s, ngx_connection_t *c) +{ + ngx_msec_t timeout; + ngx_mail_core_srv_conf_t *cscf; + ngx_mail_smtp_srv_conf_t *sscf; + + cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); + sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module); + + timeout = sscf->greeting_delay ? sscf->greeting_delay : cscf->timeout; + ngx_add_timer(c->read, timeout); + + if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) { + ngx_mail_close_connection(c); + } + + if (sscf->greeting_delay) { + c->read->handler = ngx_mail_smtp_invalid_pipelining; + return; + } + + c->read->handler = ngx_mail_smtp_init_protocol; + + s->out = sscf->greeting; + + ngx_mail_send(c->write); +} + + +static void +ngx_mail_smtp_invalid_pipelining(ngx_event_t *rev) +{ + ngx_connection_t *c; + ngx_mail_session_t *s; + ngx_mail_core_srv_conf_t *cscf; + ngx_mail_smtp_srv_conf_t *sscf; + + c = rev->data; + s = c->data; + + c->log->action = "in delay pipelining state"; + + if (rev->timedout) { + + ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "delay greeting"); + + rev->timedout = 0; + + cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); + + c->read->handler = ngx_mail_smtp_init_protocol; + + ngx_add_timer(c->read, cscf->timeout); + + if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) { + ngx_mail_close_connection(c); + return; + } + + sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module); + + s->out = sscf->greeting; + + } else { + + ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "invalid pipelining"); + + if (s->buffer == NULL) { + if (ngx_mail_smtp_create_buffer(s, c) != NGX_OK) { + return; + } + } + + if (ngx_mail_smtp_discard_command(s, c, + "client was rejected before greeting: \"%V\"") + != NGX_OK) + { + return; + } + + s->out.len = sizeof(smtp_invalid_pipelining) - 1; + s->out.data = smtp_invalid_pipelining; + } + + ngx_mail_send(c->write); +} + + +void +ngx_mail_smtp_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_mail_smtp_create_buffer(s, c) != NGX_OK) { + return; + } + } + + s->mail_state = ngx_smtp_start; + c->read->handler = ngx_mail_smtp_auth_state; + + ngx_mail_smtp_auth_state(rev); +} + + +static ngx_int_t +ngx_mail_smtp_create_buffer(ngx_mail_session_t *s, ngx_connection_t *c) +{ + ngx_mail_smtp_srv_conf_t *sscf; + + if (ngx_array_init(&s->args, c->pool, 2, sizeof(ngx_str_t)) == NGX_ERROR) { + ngx_mail_session_internal_server_error(s); + return NGX_ERROR; + } + + sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module); + + s->buffer = ngx_create_temp_buf(c->pool, sscf->client_buffer_size); + if (s->buffer == NULL) { + ngx_mail_session_internal_server_error(s); + return NGX_ERROR; + } + + return NGX_OK; +} + + +void +ngx_mail_smtp_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, "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, c); + + if (rc == NGX_AGAIN || rc == NGX_ERROR) { + return; + } + + s->out.len = sizeof(smtp_ok) - 1; + s->out.data = smtp_ok; + + if (rc == NGX_OK) { + switch (s->mail_state) { + + case ngx_smtp_start: + + switch (s->command) { + + case NGX_SMTP_HELO: + case NGX_SMTP_EHLO: + rc = ngx_mail_smtp_helo(s, c); + break; + + case NGX_SMTP_AUTH: + rc = ngx_mail_smtp_auth(s, c); + break; + + case NGX_SMTP_QUIT: + s->quit = 1; + s->out.len = sizeof(smtp_bye) - 1; + s->out.data = smtp_bye; + break; + + case NGX_SMTP_MAIL: + rc = ngx_mail_smtp_mail(s, c); + break; + + case NGX_SMTP_NOOP: + case NGX_SMTP_RSET: + break; + + case NGX_SMTP_STARTTLS: + rc = ngx_mail_smtp_starttls(s, c); + break; + + default: + rc = NGX_MAIL_PARSE_INVALID_COMMAND; + break; + } + + break; + + case ngx_smtp_auth_login_username: + rc = ngx_mail_auth_login_username(s, c); + + s->out.len = sizeof(smtp_password) - 1; + s->out.data = smtp_password; + s->mail_state = ngx_smtp_auth_login_password; + break; + + case ngx_smtp_auth_login_password: + rc = ngx_mail_auth_login_password(s, c); + break; + + case ngx_smtp_auth_plain: + rc = ngx_mail_auth_plain(s, c, 0); + break; + + case ngx_smtp_auth_cram_md5: + rc = ngx_mail_auth_cram_md5(s, c); + 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_smtp_start; + s->state = 0; + + s->out.len = sizeof(smtp_invalid_command) - 1; + s->out.data = smtp_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_smtp_helo(ngx_mail_session_t *s, ngx_connection_t *c) +{ + ngx_str_t *arg; + ngx_mail_smtp_srv_conf_t *sscf; +#if (NGX_MAIL_SSL) + ngx_mail_ssl_conf_t *sslcf; +#endif + + if (s->args.nelts != 1) { + s->out.len = sizeof(smtp_invalid_argument) - 1; + s->out.data = smtp_invalid_argument; + s->state = 0; + return NGX_OK; + } + + 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) { + return NGX_ERROR; + } + + ngx_memcpy(s->smtp_helo.data, arg[0].data, arg[0].len); + + sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module); + + if (s->command == NGX_SMTP_HELO) { + s->out = sscf->server_name; + + } else { + s->esmtp = 1; + +#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) { + s->out = sscf->starttls_capability; + return NGX_OK; + } + + if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) { + s->out = sscf->starttls_only_capability; + return NGX_OK; + } + } +#endif + + s->out = sscf->capability; + } + + return NGX_OK; +} + + +static ngx_int_t +ngx_mail_smtp_auth(ngx_mail_session_t *s, ngx_connection_t *c) +{ + ngx_int_t rc; + ngx_mail_core_srv_conf_t *cscf; + ngx_mail_smtp_srv_conf_t *sscf; + +#if (NGX_MAIL_SSL) + if (ngx_mail_starttls_only(s, c)) { + return NGX_MAIL_PARSE_INVALID_COMMAND; + } +#endif + + if (s->args.nelts == 0) { + s->out.len = sizeof(smtp_invalid_argument) - 1; + s->out.data = smtp_invalid_argument; + s->state = 0; + return NGX_OK; + } + + rc = ngx_mail_auth_parse(s, c); + + switch (rc) { + + case NGX_MAIL_AUTH_LOGIN: + + s->out.len = sizeof(smtp_username) - 1; + s->out.data = smtp_username; + s->mail_state = ngx_smtp_auth_login_username; + + return NGX_OK; + + case NGX_MAIL_AUTH_PLAIN: + + s->out.len = sizeof(smtp_next) - 1; + s->out.data = smtp_next; + s->mail_state = ngx_smtp_auth_plain; + + return NGX_OK; + + case NGX_MAIL_AUTH_CRAM_MD5: + + sscf = ngx_mail_get_module_srv_conf(s, ngx_mail_smtp_module); + + if (!(sscf->auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED)) { + return NGX_MAIL_PARSE_INVALID_COMMAND; + } + + if (s->salt.data == NULL) { + cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); + + if (ngx_mail_salt(s, c, cscf) != NGX_OK) { + return NGX_ERROR; + } + } + + if (ngx_mail_auth_cram_md5_salt(s, c, "334 ", 4) == NGX_OK) { + s->mail_state = ngx_smtp_auth_cram_md5; + return NGX_OK; + } + + return NGX_ERROR; + } + + return rc; +} + + +static ngx_int_t +ngx_mail_smtp_mail(ngx_mail_session_t *s, ngx_connection_t *c) +{ + ngx_mail_smtp_log_rejected_command(s, c, "client was rejected: \"%V\""); + + s->out.len = sizeof(smtp_auth_required) - 1; + s->out.data = smtp_auth_required; + + return NGX_OK; +} + + +static ngx_int_t +ngx_mail_smtp_starttls(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) { + + /* + * RFC3207 requires us to discard any knowledge + * obtained from client before STARTTLS. + */ + + s->smtp_helo.len = 0; + s->smtp_helo.data = NULL; + + c->read->handler = ngx_mail_starttls_handler; + return NGX_OK; + } + } + +#endif + + return NGX_MAIL_PARSE_INVALID_COMMAND; +} + + +static ngx_int_t +ngx_mail_smtp_discard_command(ngx_mail_session_t *s, ngx_connection_t *c, + char *err) +{ + ssize_t n; + + n = c->recv(c, s->buffer->last, s->buffer->end - s->buffer->last); + + if (n == NGX_ERROR || n == 0) { + ngx_mail_close_connection(c); + return NGX_ERROR; + } + + if (n > 0) { + s->buffer->last += n; + } + + if (n == NGX_AGAIN) { + if (ngx_handle_read_event(c->read, 0) == NGX_ERROR) { + ngx_mail_session_internal_server_error(s); + return NGX_ERROR; + } + + return NGX_AGAIN; + } + + ngx_mail_smtp_log_rejected_command(s, c, err); + + s->buffer->pos = s->buffer->start; + s->buffer->last = s->buffer->start; + + return NGX_OK; +} + + +static void +ngx_mail_smtp_log_rejected_command(ngx_mail_session_t *s, ngx_connection_t *c, + char *err) +{ + u_char ch; + ngx_str_t cmd; + ngx_uint_t i; + + if (c->log->log_level < NGX_LOG_INFO) { + return; + } + + cmd.len = s->buffer->last - s->buffer->start; + cmd.data = s->buffer->start; + + for (i = 0; i < cmd.len; i++) { + ch = cmd.data[i]; + + if (ch != CR && ch != LF) { + continue; + } + + cmd.data[i] = '_'; + } + + cmd.len = i; + + ngx_log_error(NGX_LOG_INFO, c->log, 0, err, &cmd); +} |