From 1b171ea80eb559fe4f4529a20bc68e1fb0ea2226 Mon Sep 17 00:00:00 2001 From: Vsevolod Stakhov Date: Wed, 2 May 2012 16:52:23 +0400 Subject: [PATCH] * Add emulating of session in case of dnsbl reject. --- src/smtp_proxy.c | 171 ++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 154 insertions(+), 17 deletions(-) diff --git a/src/smtp_proxy.c b/src/smtp_proxy.c index 6ebc135f5..78bfaa68d 100644 --- a/src/smtp_proxy.c +++ b/src/smtp_proxy.c @@ -47,6 +47,8 @@ #define DEFAULT_PROXY_BUF_LEN 100 * 1024 +#define SMTP_MAXERRORS 15 + static sig_atomic_t wanna_die = 0; /* Init functions */ @@ -76,6 +78,8 @@ struct smtp_proxy_ctx { gboolean use_xclient; + gboolean instant_reject; + gsize proxy_buf_len; struct rspamd_dns_resolver *resolver; @@ -92,7 +96,8 @@ enum rspamd_smtp_proxy_state { SMTP_PROXY_STATE_GREETING, SMTP_PROXY_STATE_XCLIENT, SMTP_PROXY_STATE_PROXY, - SMTP_PROXY_STATE_REJECT + SMTP_PROXY_STATE_REJECT, + SMTP_PROXY_STATE_REJECT_EMULATE }; struct smtp_proxy_session { @@ -126,6 +131,11 @@ struct smtp_proxy_session { guint rbl_requests; gchar *dnsbl_applied; + + gchar *from; + gchar *rcpt; + + guint errors; }; #ifndef HAVE_SA_SIGINFO @@ -204,10 +214,16 @@ free_smtp_proxy_session (gpointer arg) g_string_free (session->upstream_greeting, TRUE); } - if (session->state != SMTP_PROXY_STATE_PROXY && session->state != SMTP_PROXY_STATE_REJECT) { + if (session->state != SMTP_PROXY_STATE_PROXY && session->state != SMTP_PROXY_STATE_REJECT && + session->state != SMTP_PROXY_STATE_REJECT_EMULATE) { /* Send 521 fatal error */ write (session->sock, fatal_smtp_error, sizeof (fatal_smtp_error)); } + else if ((session->state == SMTP_PROXY_STATE_REJECT || session->state == SMTP_PROXY_STATE_REJECT_EMULATE) && + session->from && session->rcpt && session->dnsbl_applied) { + msg_info ("reject by %s mail from <%s> to <%s>, ip: %s", session->dnsbl_applied, + session->from, session->rcpt, inet_ntoa (session->client_addr)); + } close (session->sock); @@ -501,12 +517,23 @@ smtp_dnsbl_cb (struct rspamd_dns_reply *reply, void *arg) } } else { - /* TODO: add handler for denied connections */ - msg_info ("%s is denied by dnsbl: %s", inet_ntoa (session->client_addr), session->dnsbl_applied); - if (!rspamd_dispatcher_write (session->dispatcher, - make_smtp_error (session->pool, 521, "%s Client denied by %s", "5.2.1", session->dnsbl_applied), - 0, FALSE, TRUE)) { - msg_err ("cannot write smtp error"); + if (session->ctx->instant_reject) { + msg_info ("reject %s is denied by dnsbl: %s", + inet_ntoa (session->client_addr), session->dnsbl_applied); + if (!rspamd_dispatcher_write (session->dispatcher, + make_smtp_error (session->pool, 521, "%s Client denied by %s", "5.2.1", session->dnsbl_applied), + 0, FALSE, TRUE)) { + msg_err ("cannot write smtp error"); + } + } + else { + /* Emulate fake smtp session */ + rspamd_set_dispatcher_policy (session->dispatcher, BUFFER_LINE, 0); + if (!rspamd_dispatcher_write (session->dispatcher, + make_smtp_error (session->pool, 220, "smtp ready"), + 0, FALSE, TRUE)) { + msg_err ("cannot write smtp reply"); + } } rspamd_dispatcher_restore (session->dispatcher); } @@ -711,6 +738,53 @@ smtp_dns_cb (struct rspamd_dns_reply *reply, void *arg) } } +static void +proxy_parse_smtp_input (f_str_t *line, struct smtp_proxy_session *session) +{ + gchar *p, *c, *end; + gsize len; + + p = line->begin; + end = line->begin + line->len; + if (line->len >= sizeof("rcpt to: ") - 1 && (*p == 'r' || *p == 'R') && session->rcpt == NULL) { + if (g_ascii_strncasecmp (p, "rcpt to: ", sizeof ("rcpt to: ") - 1) == 0) { + p += sizeof ("rcpt to: ") - 1; + /* Skip spaces */ + while ((g_ascii_isspace (*p) || *p == '<') && p < end) { + p ++; + } + c = p; + while (!(g_ascii_isspace (*p) || *p == '>') && p < end) { + p ++; + } + len = p - c; + session->rcpt = memory_pool_alloc (session->pool, len + 1); + rspamd_strlcpy (session->rcpt, c, len + 1); + } + } + else if (line->len >= sizeof("mail from: ") - 1 && (*p == 'm' || *p == 'M') && session->from == NULL) { + if (g_ascii_strncasecmp (p, "mail from: ", sizeof ("mail from: ") - 1) == 0) { + p += sizeof ("mail from: ") - 1; + /* Skip spaces */ + while ((g_ascii_isspace (*p) || *p == '<') && p < end) { + p ++; + } + c = p; + while (!(g_ascii_isspace (*p) || *p == '>') && p < end) { + p ++; + } + len = p - c; + session->from = memory_pool_alloc (session->pool, len + 1); + rspamd_strlcpy (session->from, c, len + 1); + } + } + else if (line->len >= sizeof ("quit") - 1 && (*p == 'q' || *p == 'Q')) { + if (g_ascii_strncasecmp (p, "quit", sizeof ("quit") - 1) == 0) { + session->state = SMTP_PROXY_STATE_REJECT; + } + } +} + /* * Callback that is called when there is data to read in buffer */ @@ -718,15 +792,60 @@ static gboolean smtp_proxy_read_socket (f_str_t * in, void *arg) { struct smtp_proxy_session *session = arg; + gchar *p; - /* This can be called only if client is using invalid pipelining */ - session->state = SMTP_PROXY_STATE_REJECT; - if (!rspamd_dispatcher_write (session->dispatcher, - make_smtp_error (session->pool, 521, "%s Improper use of SMTP command pipelining", "5.2.1"), - 0, FALSE, TRUE)) { - msg_err ("cannot write smtp error"); + if (session->state != SMTP_PROXY_STATE_REJECT_EMULATE) { + /* This can be called only if client is using invalid pipelining */ + session->state = SMTP_PROXY_STATE_REJECT; + if (!rspamd_dispatcher_write (session->dispatcher, + make_smtp_error (session->pool, 521, "%s Improper use of SMTP command pipelining", "5.2.1"), + 0, FALSE, TRUE)) { + msg_err ("cannot write smtp error"); + } + destroy_session (session->s); + } + else { + /* Try to extract data */ + p = in->begin; + if (in->len >= sizeof ("helo") - 1 && (*p == 'h' || *p == 'H' || *p == 'e' || *p == 'E')) { + return rspamd_dispatcher_write (session->dispatcher, + "220 smtp ready" CRLF, + 0, FALSE, TRUE); + } + else if (in->len > 0) { + proxy_parse_smtp_input (in, session); + } + if (session->state == SMTP_PROXY_STATE_REJECT) { + /* Received QUIT command */ + if (!rspamd_dispatcher_write (session->dispatcher, + "221 2.0.0 Bye" CRLF, + 0, FALSE, TRUE)) { + msg_err ("cannot write smtp error"); + } + destroy_session (session->s); + return FALSE; + } + if (session->rcpt != NULL) { + session->errors ++; + if (session->errors > SMTP_MAXERRORS) { + if (!rspamd_dispatcher_write (session->dispatcher, + "521 5.2.1 Maximum errors reached" CRLF, + 0, FALSE, TRUE)) { + msg_err ("cannot write smtp error"); + } + destroy_session (session->s); + return FALSE; + } + return rspamd_dispatcher_write (session->dispatcher, + make_smtp_error (session->pool, 521, "%s Client denied by %s", "5.2.1", session->dnsbl_applied), + 0, FALSE, TRUE); + } + else { + return rspamd_dispatcher_write (session->dispatcher, + "250 smtp ready" CRLF, + 0, FALSE, TRUE); + } } - destroy_session (session->s); return FALSE; } @@ -739,8 +858,15 @@ smtp_proxy_write_socket (void *arg) { struct smtp_proxy_session *session = arg; - destroy_session (session->s); - return FALSE; + if (session->ctx->instant_reject) { + destroy_session (session->s); + return FALSE; + } + else { + session->state = SMTP_PROXY_STATE_REJECT_EMULATE; + } + + return TRUE; } /* @@ -752,6 +878,14 @@ smtp_proxy_err_socket (GError * err, void *arg) struct smtp_proxy_session *session = arg; if (err) { + if (err->code == ETIMEDOUT) { + /* Write smtp error */ + if (!rspamd_dispatcher_write (session->dispatcher, + "421 4.4.2 Error: timeout exceeded" CRLF, + 0, FALSE, TRUE)) { + msg_err ("cannot write smtp error"); + } + } msg_info ("abnormally closing connection, error: %s", err->message); g_error_free (err); } @@ -836,6 +970,7 @@ init_smtp_proxy (void) /* Set default values */ ctx->smtp_timeout_raw = 300000; ctx->smtp_delay = 0; + ctx->instant_reject = TRUE; register_worker_opt (type, "upstreams", xml_handle_string, ctx, G_STRUCT_OFFSET (struct smtp_proxy_ctx, upstreams_str)); @@ -847,6 +982,8 @@ init_smtp_proxy (void) G_STRUCT_OFFSET (struct smtp_proxy_ctx, delay_jitter)); register_worker_opt (type, "xclient", xml_handle_boolean, ctx, G_STRUCT_OFFSET (struct smtp_proxy_ctx, use_xclient)); + register_worker_opt (type, "instant_reject", xml_handle_boolean, ctx, + G_STRUCT_OFFSET (struct smtp_proxy_ctx, instant_reject)); register_worker_opt (type, "proxy_buffer", xml_handle_size, ctx, G_STRUCT_OFFSET (struct smtp_proxy_ctx, proxy_buf_len)); register_worker_opt (type, "dnsbl", xml_handle_list, ctx, -- 2.39.5