diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/src/smtp_in.c | 214 |
1 files changed, 117 insertions, 97 deletions
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c index 0935d212b..e8692ce56 100644 --- a/src/src/smtp_in.c +++ b/src/src/smtp_in.c @@ -82,19 +82,23 @@ enum { MAIL_CMD, RCPT_CMD, RSET_CMD, + /* This is a dummy to identify the non-sync commands when not pipelining */ + + NON_SYNC_CMD_NON_PIPELINING, + /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and processed the message is sent using a series of BDAT commands" implies that BDAT should be synchronized. However, we see Google, at least, sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for - processing of the RPCT response(s). We shall do the same, and not require - synch for BDAT. */ + processing of the RCPT response(s). We shall do the same, and not require + synch for BDAT. Worse, as the chunk may (very likely will) follow the + command-header in the same packet we cannot do the usual "is there any + follow-on data after the commmand line" even for non-pipeline mode. + So we'll need an explicit check after reading the expected chunk amount + when non-pipe, before sennding the ACK. */ BDAT_CMD, - /* This is a dummy to identify the non-sync commands when not pipelining */ - - NON_SYNC_CMD_NON_PIPELINING, - /* I have been unable to find a statement about the use of pipelining with AUTH, so to be on the safe side it is here, though I kind of feel it should be up there with the synchronized commands. */ @@ -307,6 +311,97 @@ static void smtp_quit_handler(uschar **, uschar **); static void smtp_rset_handler(void); /************************************************* +* Recheck synchronization * +*************************************************/ + +/* Synchronization checks can never be perfect because a packet may be on its +way but not arrived when the check is done. Such checks can in any case only be +done when TLS is not in use. Normally, the checks happen when commands are +read: Exim ensures that there is no more input in the input buffer. In normal +cases, the response to the command will be fast, and there is no further check. + +However, for some commands an ACL is run, and that can include delays. In those +cases, it is useful to do another check on the input just before sending the +response. This also applies at the start of a connection. This function does +that check by means of the select() function, as long as the facility is not +disabled or inappropriate. A failure of select() is ignored. + +When there is unwanted input, we read it so that it appears in the log of the +error. + +Arguments: none +Returns: TRUE if all is well; FALSE if there is input pending +*/ + +static BOOL +check_sync(void) +{ +int fd, rc; +fd_set fds; +struct timeval tzero; + +if (!smtp_enforce_sync || sender_host_address == NULL || + sender_host_notsocket || tls_in.active >= 0) + return TRUE; + +fd = fileno(smtp_in); +FD_ZERO(&fds); +FD_SET(fd, &fds); +tzero.tv_sec = 0; +tzero.tv_usec = 0; +rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero); + +if (rc <= 0) return TRUE; /* Not ready to read */ +rc = smtp_getc(); +if (rc < 0) return TRUE; /* End of file or error */ + +smtp_ungetc(rc); +rc = smtp_inend - smtp_inptr; +if (rc > 150) rc = 150; +smtp_inptr[rc] = 0; +return FALSE; +} + + + +/************************************************* +* Log incomplete transactions * +*************************************************/ + +/* This function is called after a transaction has been aborted by RSET, QUIT, +connection drops or other errors. It logs the envelope information received +so far in order to preserve address verification attempts. + +Argument: string to indicate what aborted the transaction +Returns: nothing +*/ + +static void +incomplete_transaction_log(uschar *what) +{ +if (sender_address == NULL || /* No transaction in progress */ + !LOGGING(smtp_incomplete_transaction)) + return; + +/* Build list of recipients for logging */ + +if (recipients_count > 0) + { + int i; + raw_recipients = store_get(recipients_count * sizeof(uschar *)); + for (i = 0; i < recipients_count; i++) + raw_recipients[i] = recipients_list[i].address; + raw_recipients_count = recipients_count; + } + +log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS, + "%s incomplete transaction (%s)", host_and_ident(TRUE), what); +} + + + + +/************************************************* * SMTP version of getc() * *************************************************/ @@ -394,6 +489,22 @@ for(;;) receive_getc = lwr_receive_getc; receive_ungetc = lwr_receive_ungetc; + /* Unless PIPELINING was offered, there should be no next command + until after we ack that chunk */ + + if (!pipelining_advertised && !check_sync()) + { + incomplete_transaction_log(US"sync failure"); + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error " + "(next input sent too soon: pipelining was not advertised): " + "rejected \"%s\" %s next input=\"%s\"", + smtp_cmd_buffer, host_and_ident(TRUE), + string_printing(smtp_inptr)); + (void) synprot_error(L_smtp_protocol_error, 554, NULL, + US"SMTP synchronization error"); + goto repeat_until_rset; + } + /* If not the last, ack the received chunk. The last response is delayed until after the data ACL decides on it */ @@ -1257,60 +1368,6 @@ return OTHER_CMD; /************************************************* -* Recheck synchronization * -*************************************************/ - -/* Synchronization checks can never be perfect because a packet may be on its -way but not arrived when the check is done. Such checks can in any case only be -done when TLS is not in use. Normally, the checks happen when commands are -read: Exim ensures that there is no more input in the input buffer. In normal -cases, the response to the command will be fast, and there is no further check. - -However, for some commands an ACL is run, and that can include delays. In those -cases, it is useful to do another check on the input just before sending the -response. This also applies at the start of a connection. This function does -that check by means of the select() function, as long as the facility is not -disabled or inappropriate. A failure of select() is ignored. - -When there is unwanted input, we read it so that it appears in the log of the -error. - -Arguments: none -Returns: TRUE if all is well; FALSE if there is input pending -*/ - -static BOOL -check_sync(void) -{ -int fd, rc; -fd_set fds; -struct timeval tzero; - -if (!smtp_enforce_sync || sender_host_address == NULL || - sender_host_notsocket || tls_in.active >= 0) - return TRUE; - -fd = fileno(smtp_in); -FD_ZERO(&fds); -FD_SET(fd, &fds); -tzero.tv_sec = 0; -tzero.tv_usec = 0; -rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero); - -if (rc <= 0) return TRUE; /* Not ready to read */ -rc = smtp_getc(); -if (rc < 0) return TRUE; /* End of file or error */ - -smtp_ungetc(rc); -rc = smtp_inend - smtp_inptr; -if (rc > 150) rc = 150; -smtp_inptr[rc] = 0; -return FALSE; -} - - - -/************************************************* * Forced closedown of call * *************************************************/ @@ -2635,43 +2692,6 @@ return yield; /************************************************* -* Log incomplete transactions * -*************************************************/ - -/* This function is called after a transaction has been aborted by RSET, QUIT, -connection drops or other errors. It logs the envelope information received -so far in order to preserve address verification attempts. - -Argument: string to indicate what aborted the transaction -Returns: nothing -*/ - -static void -incomplete_transaction_log(uschar *what) -{ -if (sender_address == NULL || /* No transaction in progress */ - !LOGGING(smtp_incomplete_transaction)) - return; - -/* Build list of recipients for logging */ - -if (recipients_count > 0) - { - int i; - raw_recipients = store_get(recipients_count * sizeof(uschar *)); - for (i = 0; i < recipients_count; i++) - raw_recipients[i] = recipients_list[i].address; - raw_recipients_count = recipients_count; - } - -log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS, - "%s incomplete transaction (%s)", host_and_ident(TRUE), what); -} - - - - -/************************************************* * Send SMTP response, possibly multiline * *************************************************/ |