From: Jeremy Harris Date: Thu, 23 Jul 2020 15:32:29 +0000 (+0100) Subject: OpenSSL: in server, detect TCP RST from client after QUIT under SSL, X-Git-Url: https://git.exim.org/users/heiko/exim.git/commitdiff_plain/afaf5a50b05810d75c1f7ae9d1cd83697815a997?hp=fd3b39c16b3040cc7f12dbc3afdfc4e9e6e0807b OpenSSL: in server, detect TCP RST from client after QUIT under SSL, and log different message (under new log_selector) --- diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt index 68366a4a9..e4a9301c3 100644 --- a/doc/doc-txt/experimental-spec.txt +++ b/doc/doc-txt/experimental-spec.txt @@ -666,6 +666,20 @@ and a whitespace-separated port number must be given. + +Logging protocol unusual states +--------------------------------------------------------------- +An extra log_selector, "protocol_detail" has been added in the default build. +The name may change in future, hence the Experimenal status. + +Currrently the only effect is to enable logging, under OpenSSL, +of a TCP RST received directly after a QUIT (in server mode). + +Outlook is consistently doing this; not waiting for the SMTP response +to its QUIT, not properly closing the TLS session and not properly closing +the TCP connection. Previously this resulted is an error from SSL_write +being logged. + -------------------------------------------------------------- End of file -------------------------------------------------------------- diff --git a/src/src/acl.c b/src/src/acl.c index 185a39d5d..934112c31 100644 --- a/src/src/acl.c +++ b/src/src/acl.c @@ -1944,7 +1944,8 @@ if (quota) { if (!*user_msgptr && *log_msgptr) *user_msgptr = string_sprintf("Rejected after %s: %s", - smtp_names[smtp_connection_had[smtp_ch_index-1]], *log_msgptr); + smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]], + *log_msgptr); if (rc == DEFER) f.acl_temp_details = TRUE; } } @@ -4542,7 +4543,8 @@ switch (where) /* Drop cutthrough conns, and drop heldopen verify conns if the previous was not DATA */ { - uschar prev = smtp_connection_had[smtp_ch_index-2]; + uschar prev = + smtp_connection_had[SMTP_HBUFF_PREV(SMTP_HBUFF_PREV(smtp_ch_index))]; BOOL dropverify = !(prev == SCH_DATA || prev == SCH_BDAT); cancel_cutthrough_connection(dropverify, US"quit or conndrop"); diff --git a/src/src/globals.c b/src/src/globals.c index 654c39b4f..a5df06d98 100644 --- a/src/src/globals.c +++ b/src/src/globals.c @@ -307,6 +307,7 @@ struct global_flags f = #endif .smtp_in_pipelining_advertised = FALSE, .smtp_in_pipelining_used = FALSE, + .smtp_in_quit = FALSE, .spool_file_wireformat = FALSE, .submission_mode = FALSE, .suppress_local_fixups = FALSE, @@ -1073,6 +1074,7 @@ bit_table log_options[] = { /* must be in alphabetical order, BIT_TABLE(L, outgoing_port), BIT_TABLE(L, pid), BIT_TABLE(L, pipelining), + BIT_TABLE(L, protocol_detail), #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) BIT_TABLE(L, proxy), #endif @@ -1464,6 +1466,8 @@ uschar *smtp_etrn_command = NULL; int smtp_max_synprot_errors= 3; int smtp_max_unknown_commands = 3; uschar *smtp_notquit_reason = NULL; +unsigned smtp_peer_options = 0; +unsigned smtp_peer_options_wrap= 0; uschar *smtp_ratelimit_hosts = NULL; uschar *smtp_ratelimit_mail = NULL; uschar *smtp_ratelimit_rcpt = NULL; @@ -1479,8 +1483,6 @@ int smtp_rlr_base = 0; double smtp_rlr_factor = 0.0; int smtp_rlr_limit = 0; int smtp_rlr_threshold = INT_MAX; -unsigned smtp_peer_options = 0; -unsigned smtp_peer_options_wrap= 0; #ifdef SUPPORT_I18N uschar *smtputf8_advertise_hosts = US"*"; /* overridden under test-harness */ #endif diff --git a/src/src/globals.h b/src/src/globals.h index 0c85c1150..ea326959d 100644 --- a/src/src/globals.h +++ b/src/src/globals.h @@ -269,6 +269,7 @@ extern struct global_flags { #endif BOOL smtp_in_pipelining_advertised :1; /* server advertised PIPELINING */ BOOL smtp_in_pipelining_used :1; /* server noted client using PIPELINING */ + BOOL smtp_in_quit :1; /* server noted QUIT command */ BOOL spool_file_wireformat :1; /* current -D file has CRLF rather than NL */ BOOL submission_mode :1; /* Can be forced from ACL */ BOOL suppress_local_fixups :1; /* Can be forced from ACL */ diff --git a/src/src/macros.h b/src/src/macros.h index b5221c7ec..4c5279f0a 100644 --- a/src/src/macros.h +++ b/src/src/macros.h @@ -148,6 +148,7 @@ enough to hold all the headers from a normal kind of message. */ /* The size of the circular buffer that remembers recent SMTP commands */ #define SMTP_HBUFF_SIZE 20 +#define SMTP_HBUFF_PREV(n) ((n) ? (n)-1 : SMTP_HBUFF_SIZE-1) /* The initial size of a big buffer for use in various places. It gets put into big_buffer_size and in some circumstances increased. It should be at least @@ -480,6 +481,7 @@ enum logbit { Li_outgoing_port, Li_pid, Li_pipelining, + Li_protocol_detail, Li_proxy, Li_queue_time, Li_queue_time_overall, diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c index ef3964f5c..3325d54c6 100644 --- a/src/src/smtp_in.c +++ b/src/src/smtp_in.c @@ -1733,6 +1733,7 @@ for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED)) return; case QUIT_CMD: + f.smtp_in_quit = TRUE; smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname); mac_smtp_fflush(); return; @@ -2349,8 +2350,9 @@ while (done <= 0) break; - case EOF_CMD: case QUIT_CMD: + f.smtp_in_quit = TRUE; + case EOF_CMD: done = 2; break; @@ -3835,14 +3837,13 @@ static void smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp) { HAD(SCH_QUIT); +f.smtp_in_quit = TRUE; incomplete_transaction_log(US"QUIT"); -if (acl_smtp_quit) - { - int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp); - if (rc == ERROR) +if ( acl_smtp_quit + && acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp) + == ERROR) log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", *log_msgp); - } #ifdef TCP_CORK (void) setsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_CORK, US &on, sizeof(on)); @@ -5284,10 +5285,10 @@ while (done <= 0) } if (f.smtp_in_pipelining_advertised && last_was_rcpt) smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE, - smtp_names[smtp_connection_had[smtp_ch_index-1]]); + smtp_names[smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)]]); else done = synprot_error(L_smtp_protocol_error, 503, NULL, - smtp_connection_had[smtp_ch_index-1] == SCH_DATA + smtp_connection_had[SMTP_HBUFF_PREV(smtp_ch_index)] == SCH_DATA ? US"valid RCPT command must precede DATA" : US"valid RCPT command must precede BDAT"); @@ -5551,6 +5552,7 @@ while (done <= 0) some sense is perhaps "right". */ case QUIT_CMD: + f.smtp_in_quit = TRUE; user_msg = NULL; if ( acl_smtp_quit && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c index 50384cbd5..64f60b7e4 100644 --- a/src/src/tls-openssl.c +++ b/src/src/tls-openssl.c @@ -3673,7 +3673,7 @@ context for the stashed information. */ a store reset there, so use POOL_PERM. */ /* + if CHUNKING, cmds EHLO,MAIL,RCPT(s),BDAT */ -if ((more || corked)) +if (more || corked) { if (!len) buff = US &error; /* dummy just so that string_catn is ok */ @@ -3722,9 +3722,16 @@ for (int left = len; left > 0;) return -1; case SSL_ERROR_SYSCALL: - log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", - sender_fullhost ? sender_fullhost : US"", - strerror(errno)); + if (ct_ctx || errno != ECONNRESET || !f.smtp_in_quit) + log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s", + sender_fullhost ? sender_fullhost : US"", + strerror(errno)); + else if (LOGGING(protocol_detail)) + log_write(0, LOG_MAIN, "[%s] after QUIT, client reset TCP before" + " SMTP response and TLS close\n", sender_host_address); + else + DEBUG(D_tls) debug_printf("[%s] SSL_write: after QUIT," + " client reset TCP before TLS close\n", sender_host_address); return -1; default: