Mercurial > hg > nginx
view src/mail/ngx_mail_imap_handler.c @ 9236:d9a52ebb9b00
Mail: max_commands directive.
The directive specifies the maximum number of commands allowed during
authentication, after which the connection is closed. The default
limit is 1000, which is not expected to affect any well-behaving clients,
since authentication usually requires at most several commands, though
will effectively stop malicious clients from flooding the server with
with commands.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Sat, 30 Mar 2024 05:05:53 +0300 |
parents | d7fd0acdea64 |
children | 32d4582c484d |
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_imap_module.h> static ngx_int_t ngx_mail_imap_login(ngx_mail_session_t *s, ngx_connection_t *c); static ngx_int_t ngx_mail_imap_authenticate(ngx_mail_session_t *s, ngx_connection_t *c); static ngx_int_t ngx_mail_imap_capability(ngx_mail_session_t *s, ngx_connection_t *c); static ngx_int_t ngx_mail_imap_starttls(ngx_mail_session_t *s, ngx_connection_t *c); static u_char imap_greeting[] = "* OK IMAP4 ready" 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_plain_next[] = "+ " CRLF; static u_char imap_username[] = "+ VXNlcm5hbWU6" CRLF; static u_char imap_password[] = "+ UGFzc3dvcmQ6" CRLF; static u_char imap_bye[] = "* BYE" CRLF; static u_char imap_invalid_command[] = "BAD invalid command" CRLF; void ngx_mail_imap_init_session(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_mail_core_srv_conf_t *cscf; cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); ngx_str_set(&s->out, imap_greeting); c->read->handler = ngx_mail_imap_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_imap_init_protocol(ngx_event_t *rev) { ngx_connection_t *c; ngx_mail_session_t *s; ngx_mail_imap_srv_conf_t *iscf; 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; } iscf = ngx_mail_get_module_srv_conf(s, ngx_mail_imap_module); s->buffer = ngx_create_temp_buf(c->pool, iscf->client_buffer_size); if (s->buffer == NULL) { ngx_mail_session_internal_server_error(s); return; } } s->mail_state = ngx_imap_start; c->read->handler = ngx_mail_imap_auth_state; ngx_mail_imap_auth_state(rev); } void ngx_mail_imap_auth_state(ngx_event_t *rev) { u_char *p; size_t n; ngx_int_t rc; ngx_uint_t tag; 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, "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; if (ngx_handle_read_event(c->read, 0) != NGX_OK) { ngx_mail_close_connection(c); return; } return; } s->blocked = 0; rc = ngx_mail_read_command(s, c); if (rc == NGX_AGAIN) { if (ngx_handle_read_event(c->read, 0) != NGX_OK) { ngx_mail_session_internal_server_error(s); return; } return; } if (rc == NGX_ERROR) { return; } tag = 1; s->text.len = 0; ngx_str_set(&s->out, imap_ok); if (rc == NGX_OK) { ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap auth command: %i", s->command); switch (s->mail_state) { case ngx_imap_start: switch (s->command) { case NGX_IMAP_LOGIN: rc = ngx_mail_imap_login(s, c); break; case NGX_IMAP_AUTHENTICATE: rc = ngx_mail_imap_authenticate(s, c); tag = (rc != NGX_OK); break; case NGX_IMAP_CAPABILITY: rc = ngx_mail_imap_capability(s, c); break; case NGX_IMAP_LOGOUT: s->quit = 1; ngx_str_set(&s->text, imap_bye); break; case NGX_IMAP_NOOP: break; case NGX_IMAP_STARTTLS: rc = ngx_mail_imap_starttls(s, c); break; default: rc = NGX_MAIL_PARSE_INVALID_COMMAND; break; } break; case ngx_imap_auth_login_username: rc = ngx_mail_auth_login_username(s, c, 0); tag = 0; ngx_str_set(&s->out, imap_password); s->mail_state = ngx_imap_auth_login_password; break; case ngx_imap_auth_login_password: rc = ngx_mail_auth_login_password(s, c); break; case ngx_imap_auth_plain: rc = ngx_mail_auth_plain(s, c, 0); break; case ngx_imap_auth_cram_md5: rc = ngx_mail_auth_cram_md5(s, c); break; case ngx_imap_auth_external: rc = ngx_mail_auth_external(s, c, 0); break; } } else if (rc == NGX_IMAP_NEXT) { tag = 0; ngx_str_set(&s->out, imap_next); } if (s->buffer->pos < s->buffer->last || c->read->ready) { s->blocked = 1; } 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->state = 0; ngx_str_set(&s->out, imap_invalid_command); s->mail_state = ngx_imap_start; break; } if (tag) { if (s->tag.len == 0) { ngx_str_set(&s->tag, imap_star); } if (s->tagged_line.len < s->tag.len + s->text.len + s->out.len) { s->tagged_line.len = s->tag.len + s->text.len + s->out.len; s->tagged_line.data = ngx_pnalloc(c->pool, s->tagged_line.len); if (s->tagged_line.data == NULL) { ngx_mail_close_connection(c); return; } } p = s->tagged_line.data; if (s->text.len) { p = ngx_cpymem(p, s->text.data, s->text.len); } p = ngx_cpymem(p, s->tag.data, s->tag.len); ngx_memcpy(p, s->out.data, s->out.len); s->out.len = s->text.len + s->tag.len + s->out.len; s->out.data = s->tagged_line.data; } if (rc != NGX_IMAP_NEXT) { s->args.nelts = 0; if (s->state) { /* preserve tag */ s->arg_start = s->buffer->pos; } else { if (s->buffer->pos == s->buffer->last) { s->buffer->pos = s->buffer->start; s->buffer->last = s->buffer->start; } else { n = s->buffer->last - s->buffer->pos; ngx_memmove(s->buffer->start, s->buffer->pos, n); s->buffer->pos = s->buffer->start; s->buffer->last = s->buffer->start + n; } s->tag.len = 0; } } if (ngx_handle_read_event(c->read, 0) != NGX_OK) { ngx_mail_session_internal_server_error(s); return; } ngx_mail_send(c->write); } static ngx_int_t ngx_mail_imap_login(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 arg = s->args.elts; if (s->args.nelts != 2 || arg[0].len == 0) { return NGX_MAIL_PARSE_INVALID_COMMAND; } 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); #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 return NGX_DONE; } static ngx_int_t ngx_mail_imap_authenticate(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_int_t rc; ngx_mail_core_srv_conf_t *cscf; ngx_mail_imap_srv_conf_t *iscf; #if (NGX_MAIL_SSL) if (ngx_mail_starttls_only(s, c)) { return NGX_MAIL_PARSE_INVALID_COMMAND; } #endif iscf = ngx_mail_get_module_srv_conf(s, ngx_mail_imap_module); rc = ngx_mail_auth_parse(s, c); switch (rc) { case NGX_MAIL_AUTH_LOGIN: ngx_str_set(&s->out, imap_username); s->mail_state = ngx_imap_auth_login_username; return NGX_OK; case NGX_MAIL_AUTH_LOGIN_USERNAME: ngx_str_set(&s->out, imap_password); s->mail_state = ngx_imap_auth_login_password; return ngx_mail_auth_login_username(s, c, 1); case NGX_MAIL_AUTH_PLAIN: ngx_str_set(&s->out, imap_plain_next); s->mail_state = ngx_imap_auth_plain; return NGX_OK; case NGX_MAIL_AUTH_CRAM_MD5: if (!(iscf->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, "+ ", 2) == NGX_OK) { s->mail_state = ngx_imap_auth_cram_md5; return NGX_OK; } return NGX_ERROR; case NGX_MAIL_AUTH_EXTERNAL: if (!(iscf->auth_methods & NGX_MAIL_AUTH_EXTERNAL_ENABLED)) { return NGX_MAIL_PARSE_INVALID_COMMAND; } ngx_str_set(&s->out, imap_username); s->mail_state = ngx_imap_auth_external; return NGX_OK; } return rc; } static ngx_int_t ngx_mail_imap_capability(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_mail_imap_srv_conf_t *iscf; iscf = ngx_mail_get_module_srv_conf(s, ngx_mail_imap_module); #if (NGX_MAIL_SSL) if (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->text = iscf->starttls_capability; return NGX_OK; } if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) { s->text = iscf->starttls_only_capability; return NGX_OK; } } #endif s->text = iscf->capability; return NGX_OK; } static ngx_int_t ngx_mail_imap_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) { s->buffer->pos = s->buffer->start; s->buffer->last = s->buffer->start; c->read->handler = ngx_mail_starttls_handler; return NGX_OK; } } #endif return NGX_MAIL_PARSE_INVALID_COMMAND; }