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postfix/postfix/src/cleanup/cleanup_message.c
Wietse Z Venema 7655cf261d postfix-3.10-20240917
2024-09-19 22:28:50 +10:00

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/*++
/* NAME
/* cleanup_message 3
/* SUMMARY
/* process message segment
/* SYNOPSIS
/* #include "cleanup.h"
/*
/* void cleanup_message(state, type, buf, len)
/* CLEANUP_STATE *state;
/* int type;
/* const char *buf;
/* ssize_t len;
/* DESCRIPTION
/* This module processes message content records and copies the
/* result to the queue file. It validates the input, rewrites
/* sender/recipient addresses to canonical form, inserts missing
/* message headers, and extracts information from message headers
/* to be used later when generating the extracted output segment.
/* This routine absorbs but does not emit the content to extracted
/* boundary record.
/*
/* Arguments:
/* .IP state
/* Queue file and message processing state. This state is updated
/* as records are processed and as errors happen.
/* .IP type
/* Record type.
/* .IP buf
/* Record content.
/* .IP len
/* Record content length.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#ifdef STRCASECMP_IN_STRINGS_H
#include <strings.h>
#endif
/* Utility library. */
#include <msg.h>
#include <vstring.h>
#include <vstream.h>
#include <argv.h>
#include <split_at.h>
#include <mymalloc.h>
#include <stringops.h>
#include <nvtable.h>
/* Global library. */
#include <record.h>
#include <rec_type.h>
#include <cleanup_user.h>
#include <tok822.h>
#include <lex_822.h>
#include <header_opts.h>
#include <quote_822_local.h>
#include <mail_params.h>
#include <mail_date.h>
#include <mail_addr.h>
#include <is_header.h>
#include <ext_prop.h>
#include <mail_proto.h>
#include <mime_state.h>
#include <lex_822.h>
#include <dsn_util.h>
#include <conv_time.h>
#include <info_log_addr_form.h>
#include <hfrom_format.h>
/* Application-specific. */
#include "cleanup.h"
/* cleanup_fold_header - wrap address list header */
static void cleanup_fold_header(CLEANUP_STATE *state, VSTRING *header_buf)
{
char *start_line = vstring_str(header_buf);
char *end_line;
char *next_line;
char *line;
/*
* A rewritten address list contains one address per line. The code below
* replaces newlines by spaces, to fit as many addresses on a line as
* possible (without rearranging the order of addresses). Prepending
* white space to the beginning of lines is delegated to the output
* routine.
*/
for (line = start_line; line != 0; line = next_line) {
end_line = line + strcspn(line, "\n");
if (line > start_line) {
if (end_line - start_line < 70) { /* TAB counts as one */
line[-1] = ' ';
} else {
start_line = line;
}
}
next_line = *end_line ? end_line + 1 : 0;
}
cleanup_out_header(state, header_buf);
}
/* cleanup_extract_internal - save unquoted copy of extracted address */
static char *cleanup_extract_internal(VSTRING *buffer, TOK822 *addr)
{
/*
* A little routine to stash away a copy of an address that we extracted
* from a message header line.
*/
tok822_internalize(buffer, addr->head, TOK822_STR_DEFL);
return (mystrdup(vstring_str(buffer)));
}
/* cleanup_rewrite_sender - sender address rewriting */
static void cleanup_rewrite_sender(CLEANUP_STATE *state,
const HEADER_OPTS *hdr_opts,
VSTRING *header_buf)
{
TOK822 *tree;
TOK822 **addr_list;
TOK822 **tpp;
int did_rewrite = 0;
if (msg_verbose)
msg_info("rewrite_sender: %s", hdr_opts->name);
/*
* Parse the header line, rewrite each address found, and regenerate the
* header line. Finally, pipe the result through the header line folding
* routine.
*/
tree = tok822_parse_limit(vstring_str(header_buf)
+ strlen(hdr_opts->name) + 1,
var_token_limit);
addr_list = tok822_grep(tree, TOK822_ADDR);
for (tpp = addr_list; *tpp; tpp++) {
did_rewrite |= cleanup_rewrite_tree(state->hdr_rewrite_context, *tpp);
if (state->flags & CLEANUP_FLAG_MAP_OK) {
if (cleanup_send_canon_maps
&& (cleanup_send_canon_flags & CLEANUP_CANON_FLAG_HDR_FROM))
did_rewrite |=
cleanup_map11_tree(state, *tpp, cleanup_send_canon_maps,
cleanup_ext_prop_mask & EXT_PROP_CANONICAL);
if (cleanup_comm_canon_maps
&& (cleanup_comm_canon_flags & CLEANUP_CANON_FLAG_HDR_FROM))
did_rewrite |=
cleanup_map11_tree(state, *tpp, cleanup_comm_canon_maps,
cleanup_ext_prop_mask & EXT_PROP_CANONICAL);
if (cleanup_masq_domains
&& (cleanup_masq_flags & CLEANUP_MASQ_FLAG_HDR_FROM))
did_rewrite |=
cleanup_masquerade_tree(state, *tpp, cleanup_masq_domains);
}
}
if (did_rewrite) {
vstring_truncate(header_buf, strlen(hdr_opts->name));
vstring_strcat(header_buf, ": ");
tok822_externalize(header_buf, tree, TOK822_STR_HEAD);
}
myfree((void *) addr_list);
tok822_free_tree(tree);
if ((hdr_opts->flags & HDR_OPT_DROP) == 0) {
if (did_rewrite)
cleanup_fold_header(state, header_buf);
else
cleanup_out_header(state, header_buf);
}
}
/* cleanup_rewrite_recip - recipient address rewriting */
static void cleanup_rewrite_recip(CLEANUP_STATE *state,
const HEADER_OPTS *hdr_opts,
VSTRING *header_buf)
{
TOK822 *tree;
TOK822 **addr_list;
TOK822 **tpp;
int did_rewrite = 0;
if (msg_verbose)
msg_info("rewrite_recip: %s", hdr_opts->name);
/*
* Parse the header line, rewrite each address found, and regenerate the
* header line. Finally, pipe the result through the header line folding
* routine.
*/
tree = tok822_parse_limit(vstring_str(header_buf)
+ strlen(hdr_opts->name) + 1,
var_token_limit);
addr_list = tok822_grep(tree, TOK822_ADDR);
for (tpp = addr_list; *tpp; tpp++) {
did_rewrite |= cleanup_rewrite_tree(state->hdr_rewrite_context, *tpp);
if (state->flags & CLEANUP_FLAG_MAP_OK) {
if (cleanup_rcpt_canon_maps
&& (cleanup_rcpt_canon_flags & CLEANUP_CANON_FLAG_HDR_RCPT))
did_rewrite |=
cleanup_map11_tree(state, *tpp, cleanup_rcpt_canon_maps,
cleanup_ext_prop_mask & EXT_PROP_CANONICAL);
if (cleanup_comm_canon_maps
&& (cleanup_comm_canon_flags & CLEANUP_CANON_FLAG_HDR_RCPT))
did_rewrite |=
cleanup_map11_tree(state, *tpp, cleanup_comm_canon_maps,
cleanup_ext_prop_mask & EXT_PROP_CANONICAL);
if (cleanup_masq_domains
&& (cleanup_masq_flags & CLEANUP_MASQ_FLAG_HDR_RCPT))
did_rewrite |=
cleanup_masquerade_tree(state, *tpp, cleanup_masq_domains);
}
}
if (did_rewrite) {
vstring_truncate(header_buf, strlen(hdr_opts->name));
vstring_strcat(header_buf, ": ");
tok822_externalize(header_buf, tree, TOK822_STR_HEAD);
}
myfree((void *) addr_list);
tok822_free_tree(tree);
if ((hdr_opts->flags & HDR_OPT_DROP) == 0) {
if (did_rewrite)
cleanup_fold_header(state, header_buf);
else
cleanup_out_header(state, header_buf);
}
}
/* cleanup_act_log - log action with context */
static void cleanup_act_log(CLEANUP_STATE *state,
const char *action, const char *class,
const char *content, const char *text)
{
const char *attr;
if ((attr = nvtable_find(state->attr, MAIL_ATTR_LOG_ORIGIN)) == 0)
attr = "unknown";
vstring_sprintf(state->temp1, "%s: %s: %s %.200s from %s;",
state->queue_id, action, class, content, attr);
if (state->sender)
vstring_sprintf_append(state->temp1, " from=<%s>",
info_log_addr_form_sender(state->sender));
if (state->recip)
vstring_sprintf_append(state->temp1, " to=<%s>",
info_log_addr_form_recipient(state->recip));
if ((attr = nvtable_find(state->attr, MAIL_ATTR_LOG_PROTO_NAME)) != 0)
vstring_sprintf_append(state->temp1, " proto=%s", attr);
if ((attr = nvtable_find(state->attr, MAIL_ATTR_LOG_HELO_NAME)) != 0)
vstring_sprintf_append(state->temp1, " helo=<%s>", attr);
if (text && *text)
vstring_sprintf_append(state->temp1, ": %s", text);
msg_info("%s", vstring_str(state->temp1));
}
#define CLEANUP_ACT_CTXT_HEADER "header"
#define CLEANUP_ACT_CTXT_BODY "body"
#define CLEANUP_ACT_CTXT_ANY "content"
/* cleanup_act - act upon a header/body match */
static const char *cleanup_act(CLEANUP_STATE *state, char *context,
const char *buf, const char *value,
const char *map_class)
{
const char *optional_text = value + strcspn(value, " \t");
int command_len = optional_text - value;
#ifdef DELAY_ACTION
int defer_delay;
#endif
while (*optional_text && ISSPACE(*optional_text))
optional_text++;
#define STREQUAL(x,y,l) (strncasecmp((x), (y), (l)) == 0 && (y)[l] == 0)
#define CLEANUP_ACT_DROP 0
/*
* CLEANUP_STAT_CONT and CLEANUP_STAT_DEFER both update the reason
* attribute, but CLEANUP_STAT_DEFER takes precedence. It terminates
* queue record processing, and prevents bounces from being sent.
*/
if (STREQUAL(value, "REJECT", command_len)) {
const CLEANUP_STAT_DETAIL *detail;
if (state->reason)
myfree(state->reason);
if (*optional_text) {
state->reason = dsn_prepend("5.7.1", optional_text);
if (*state->reason != '4' && *state->reason != '5') {
msg_warn("bad DSN action in %s -- need 4.x.x or 5.x.x",
optional_text);
*state->reason = '4';
}
} else {
detail = cleanup_stat_detail(CLEANUP_STAT_CONT);
state->reason = dsn_prepend(detail->dsn, detail->text);
}
if (*state->reason == '4')
state->errs |= CLEANUP_STAT_DEFER;
else
state->errs |= CLEANUP_STAT_CONT;
state->flags &= ~CLEANUP_FLAG_FILTER_ALL;
cleanup_act_log(state, "reject", context, buf, state->reason);
return (buf);
}
if (STREQUAL(value, "WARN", command_len)) {
cleanup_act_log(state, "warning", context, buf, optional_text);
return (buf);
}
if (STREQUAL(value, "INFO", command_len)) {
cleanup_act_log(state, "info", context, buf, optional_text);
return (buf);
}
if (STREQUAL(value, "FILTER", command_len)) {
if (*optional_text == 0) {
msg_warn("missing FILTER command argument in %s map", map_class);
} else if (strchr(optional_text, ':') == 0) {
msg_warn("bad FILTER command %s in %s -- "
"need transport:destination",
optional_text, map_class);
} else {
if (state->filter)
myfree(state->filter);
state->filter = mystrdup(optional_text);
cleanup_act_log(state, "filter", context, buf, optional_text);
}
return (buf);
}
if (STREQUAL(value, "PASS", command_len)) {
cleanup_act_log(state, "pass", context, buf, optional_text);
state->flags &= ~CLEANUP_FLAG_FILTER_ALL;
return (buf);
}
if (STREQUAL(value, "DISCARD", command_len)) {
cleanup_act_log(state, "discard", context, buf, optional_text);
state->flags |= CLEANUP_FLAG_DISCARD;
state->flags &= ~CLEANUP_FLAG_FILTER_ALL;
return (buf);
}
if (STREQUAL(value, "HOLD", command_len)) {
if ((state->flags & (CLEANUP_FLAG_HOLD | CLEANUP_FLAG_DISCARD)) == 0) {
cleanup_act_log(state, "hold", context, buf, optional_text);
state->flags |= CLEANUP_FLAG_HOLD;
}
return (buf);
}
/*
* The DELAY feature is disabled because it has too many problems. 1) It
* does not work on some remote file systems; 2) mail will be delivered
* anyway with "sendmail -q" etc.; 3) while the mail is queued it bogs
* down the deferred queue scan with huge amounts of useless disk I/O
* operations.
*/
#ifdef DELAY_ACTION
if (STREQUAL(value, "DELAY", command_len)) {
if ((state->flags & (CLEANUP_FLAG_HOLD | CLEANUP_FLAG_DISCARD)) == 0) {
if (*optional_text == 0) {
msg_warn("missing DELAY argument in %s map", map_class);
} else if (conv_time(optional_text, &defer_delay, 's') == 0) {
msg_warn("ignoring bad DELAY argument %s in %s map",
optional_text, map_class);
} else {
cleanup_act_log(state, "delay", context, buf, optional_text);
state->defer_delay = defer_delay;
}
}
return (buf);
}
#endif
if (STREQUAL(value, "PREPEND", command_len)) {
if (*optional_text == 0) {
msg_warn("PREPEND action without text in %s map", map_class);
} else if (strcmp(context, CLEANUP_ACT_CTXT_HEADER) == 0) {
if (!is_header(optional_text)) {
msg_warn("bad PREPEND header text \"%s\" in %s map -- "
"need \"headername: headervalue\"",
optional_text, map_class);
}
/*
* By design, cleanup_out_header() may modify content. Play safe
* and prepare for future developments.
*/
else {
VSTRING *temp;
cleanup_act_log(state, "prepend", context, buf, optional_text);
temp = vstring_strcpy(vstring_alloc(strlen(optional_text)),
optional_text);
cleanup_out_header(state, temp);
vstring_free(temp);
}
} else {
cleanup_act_log(state, "prepend", context, buf, optional_text);
cleanup_out_string(state, REC_TYPE_NORM, optional_text);
}
return (buf);
}
if (STREQUAL(value, "REPLACE", command_len)) {
if (*optional_text == 0) {
msg_warn("REPLACE action without text in %s map", map_class);
return (buf);
} else if (strcmp(context, CLEANUP_ACT_CTXT_HEADER) == 0
&& !is_header(optional_text)) {
msg_warn("bad REPLACE header text \"%s\" in %s map -- "
"need \"headername: headervalue\"",
optional_text, map_class);
return (buf);
} else {
cleanup_act_log(state, "replace", context, buf, optional_text);
return (mystrdup(optional_text));
}
}
if (STREQUAL(value, "REDIRECT", command_len)) {
if (strchr(optional_text, '@') == 0) {
msg_warn("bad REDIRECT target \"%s\" in %s map -- "
"need user@domain",
optional_text, map_class);
} else {
if (state->redirect)
myfree(state->redirect);
state->redirect = mystrdup(optional_text);
cleanup_act_log(state, "redirect", context, buf, optional_text);
state->flags &= ~CLEANUP_FLAG_FILTER_ALL;
}
return (buf);
}
if (STREQUAL(value, "BCC", command_len)) {
if (strchr(optional_text, '@') == 0) {
msg_warn("bad BCC address \"%s\" in %s map -- "
"need user@domain",
optional_text, map_class);
} else {
if (state->hbc_rcpt == 0)
state->hbc_rcpt = argv_alloc(1);
argv_add(state->hbc_rcpt, optional_text, (char *) 0);
cleanup_act_log(state, "bcc", context, buf, optional_text);
}
return (buf);
}
if (STREQUAL(value, "STRIP", command_len)) {
cleanup_act_log(state, "strip", context, buf, optional_text);
return (CLEANUP_ACT_DROP);
}
/* Allow and ignore optional text after the action. */
if (STREQUAL(value, "IGNORE", command_len))
return (CLEANUP_ACT_DROP);
if (STREQUAL(value, "DUNNO", command_len)) /* preferred */
return (buf);
if (STREQUAL(value, "OK", command_len)) /* compat */
return (buf);
msg_warn("unknown command in %s map: %s", map_class, value);
return (buf);
}
/* cleanup_header_callback - process one complete header line */
static void cleanup_header_callback(void *context, int header_class,
const HEADER_OPTS *hdr_opts,
VSTRING *header_buf,
off_t unused_offset)
{
CLEANUP_STATE *state = (CLEANUP_STATE *) context;
const char *myname = "cleanup_header_callback";
char *hdrval;
struct code_map {
const char *name;
const char *encoding;
};
static struct code_map code_map[] = { /* RFC 2045 */
"7bit", MAIL_ATTR_ENC_7BIT,
"8bit", MAIL_ATTR_ENC_8BIT,
"binary", MAIL_ATTR_ENC_8BIT, /* XXX Violation */
"quoted-printable", MAIL_ATTR_ENC_7BIT,
"base64", MAIL_ATTR_ENC_7BIT,
0,
};
struct code_map *cmp;
MAPS *checks;
const char *map_class;
if (msg_verbose)
msg_info("%s: '%.200s'", myname, vstring_str(header_buf));
/*
* Crude header filtering. This stops malware that isn't sophisticated
* enough to use fancy header encodings.
*/
#define CHECK(class, maps, var_name) \
(header_class == class && (map_class = var_name, checks = maps) != 0)
if (hdr_opts && (hdr_opts->flags & HDR_OPT_MIME))
header_class = MIME_HDR_MULTIPART;
/* Update the Received: header count before maybe dropping headers below. */
if (hdr_opts && hdr_opts->type == HDR_RECEIVED)
state->hop_count += 1;
if ((state->flags & CLEANUP_FLAG_FILTER)
&& (CHECK(MIME_HDR_PRIMARY, cleanup_header_checks, VAR_HEADER_CHECKS)
|| CHECK(MIME_HDR_MULTIPART, cleanup_mimehdr_checks, VAR_MIMEHDR_CHECKS)
|| CHECK(MIME_HDR_NESTED, cleanup_nesthdr_checks, VAR_NESTHDR_CHECKS))) {
char *header = vstring_str(header_buf);
const char *value;
if ((value = maps_find(checks, header, 0)) != 0) {
const char *result;
if ((result = cleanup_act(state, CLEANUP_ACT_CTXT_HEADER,
header, value, map_class))
== CLEANUP_ACT_DROP) {
return;
} else if (result != header) {
vstring_strcpy(header_buf, result);
hdr_opts = header_opts_find(result);
myfree((void *) result);
}
} else if (checks->error) {
msg_warn("%s: %s map lookup problem -- "
"message not accepted, try again later",
state->queue_id, checks->title);
state->errs |= CLEANUP_STAT_WRITE;
}
}
/*
* If this is an "unknown" header, just copy it to the output without
* even bothering to fold long lines. cleanup_out() will split long
* headers that do not fit a REC_TYPE_NORM record.
*/
if (hdr_opts == 0) {
cleanup_out_header(state, header_buf);
return;
}
/*
* Allow 8-bit type info to override 7-bit type info. XXX Should reuse
* the effort that went into MIME header parsing.
*/
hdrval = vstring_str(header_buf) + strlen(hdr_opts->name) + 1;
while (ISSPACE(*hdrval))
hdrval++;
/* trimblanks(hdrval, 0)[0] = 0; */
if (var_auto_8bit_enc_hdr
&& hdr_opts->type == HDR_CONTENT_TRANSFER_ENCODING) {
for (cmp = code_map; cmp->name != 0; cmp++) {
if (strcasecmp(hdrval, cmp->name) == 0) {
if (strcasecmp(cmp->encoding, MAIL_ATTR_ENC_8BIT) == 0)
nvtable_update(state->attr, MAIL_ATTR_ENCODING,
cmp->encoding);
break;
}
}
}
/*
* Copy attachment etc. header blocks without further inspection.
*/
if (header_class != MIME_HDR_PRIMARY) {
cleanup_out_header(state, header_buf);
return;
}
/*
* Known header. Remember that we have seen at least one. Find out what
* we should do with this header: delete, count, rewrite. Note that we
* should examine headers even when they will be deleted from the output,
* because the addresses in those headers might be needed elsewhere.
*
* XXX 2821: Return-path breakage.
*
* RFC 821 specifies: When the receiver-SMTP makes the "final delivery" of a
* message it inserts at the beginning of the mail data a return path
* line. The return path line preserves the information in the
* <reverse-path> from the MAIL command. Here, final delivery means the
* message leaves the SMTP world. Normally, this would mean it has been
* delivered to the destination user, but in some cases it may be further
* processed and transmitted by another mail system.
*
* And that is what Postfix implements. Delivery agents prepend
* Return-Path:. In order to avoid cluttering up the message with
* possibly inconsistent Return-Path: information (the sender can change
* as the result of mail forwarding or mailing list delivery), Postfix
* removes any existing Return-Path: headers.
*
* RFC 2821 Section 4.4 specifies: A message-originating SMTP system
* SHOULD NOT send a message that already contains a Return-path header.
* SMTP servers performing a relay function MUST NOT inspect the message
* data, and especially not to the extent needed to determine if
* Return-path headers are present. SMTP servers making final delivery
* MAY remove Return-path headers before adding their own.
*/
else {
state->headers_seen |= (1 << hdr_opts->type);
if (hdr_opts->type == HDR_MESSAGE_ID) {
ssize_t len;
msg_info("%s: message-id=%s", state->queue_id, hdrval);
if (state->message_id == 0 && (len = balpar(hdrval, "<>")) > 0)
/* This Message ID may end up in threaded bounces. */
state->message_id = printable(mystrndup(hdrval, len), ' ');
}
if (hdr_opts->type == HDR_RESENT_MESSAGE_ID)
msg_info("%s: resent-message-id=%s", state->queue_id, hdrval);
if (hdr_opts->type == HDR_RECEIVED) {
if (state->hop_count >= var_hopcount_limit) {
msg_warn("%s: message rejected: hopcount exceeded",
state->queue_id);
state->errs |= CLEANUP_STAT_HOPS;
}
/* Save our Received: header after maybe updating headers above. */
if (state->hop_count == 1)
argv_add(state->auto_hdrs, vstring_str(header_buf), ARGV_END);
}
if (CLEANUP_OUT_OK(state)) {
if (hdr_opts->flags & HDR_OPT_RR)
state->resent = "Resent-";
if ((hdr_opts->flags & HDR_OPT_SENDER)
&& state->hdr_rewrite_context) {
cleanup_rewrite_sender(state, hdr_opts, header_buf);
} else if ((hdr_opts->flags & HDR_OPT_RECIP)
&& state->hdr_rewrite_context) {
cleanup_rewrite_recip(state, hdr_opts, header_buf);
} else if ((hdr_opts->flags & HDR_OPT_DROP) == 0) {
cleanup_out_header(state, header_buf);
}
}
}
}
/* cleanup_header_done_callback - insert missing message headers */
static void cleanup_header_done_callback(void *context)
{
const char *myname = "cleanup_header_done_callback";
CLEANUP_STATE *state = (CLEANUP_STATE *) context;
char time_stamp[1024]; /* XXX locale dependent? */
struct tm *tp;
TOK822 *token;
TOK822 *dummy_token;
time_t tv;
/*
* XXX Workaround: when we reach the end of headers, mime_state_update()
* may execute up to three call-backs before returning to the caller:
* head_out(), head_end(), and body_out() or body_end(). As long as
* call-backs don't return a result, each call-back has to check for
* itself if the previous call-back experienced a problem.
*/
if (CLEANUP_OUT_OK(state) == 0)
return;
/*
* Future proofing: the Milter client's header suppression algorithm
* assumes that the MTA prepends its own Received: header. This
* assumption may be violated after some source-code update. The
* following check ensures consistency, at least for local submission.
*/
if (state->hop_count < 1) {
msg_warn("%s: message rejected: no Received: header",
state->queue_id);
state->errs |= CLEANUP_STAT_BAD;
return;
}
/*
* Add a missing (Resent-)Message-Id: header. The message ID gives the
* time in GMT units, plus the local queue ID.
*
* XXX Message-Id is not a required message header (RFC 822 and RFC 2822).
*
* XXX It is the queue ID non-inode bits that prevent messages from getting
* the same Message-Id within the same second.
*
* XXX An arbitrary amount of time may pass between the start of the mail
* transaction and the creation of a queue file. Since we guarantee queue
* ID uniqueness only within a second, we must ensure that the time in
* the message ID matches the queue ID creation time, as long as we use
* the queue ID in the message ID.
*
* XXX We log a dummy name=value record so that we (hopefully) don't break
* compatibility with existing logfile analyzers, and so that we don't
* complicate future code that wants to log more name=value attributes.
*/
if ((state->hdr_rewrite_context || var_always_add_hdrs)
&& (state->headers_seen & (1 << (state->resent[0] ?
HDR_RESENT_MESSAGE_ID : HDR_MESSAGE_ID))) == 0) {
if (var_long_queue_ids) {
vstring_sprintf(state->temp1, "%s@%s",
state->queue_id, var_myhostname);
} else {
tv = state->handle->ctime.tv_sec;
tp = gmtime(&tv);
strftime(time_stamp, sizeof(time_stamp), "%Y%m%d%H%M%S", tp);
vstring_sprintf(state->temp1, "%s.%s@%s",
time_stamp, state->queue_id, var_myhostname);
}
cleanup_out_format(state, REC_TYPE_NORM, "%sMessage-Id: <%s>",
state->resent, vstring_str(state->temp1));
msg_info("%s: %smessage-id=<%s>",
state->queue_id, *state->resent ? "resent-" : "",
vstring_str(state->temp1));
state->headers_seen |= (1 << (state->resent[0] ?
HDR_RESENT_MESSAGE_ID : HDR_MESSAGE_ID));
if (state->resent[0] == 0 && state->message_id == 0)
state->message_id = concatenate("<", vstring_str(state->temp1),
">", (char *) 0);
}
if ((state->headers_seen & (1 << HDR_MESSAGE_ID)) == 0)
msg_info("%s: message-id=<>", state->queue_id);
/*
* Add a missing (Resent-)Date: header. The date is in local time units,
* with the GMT offset at the end.
*/
if ((state->hdr_rewrite_context || var_always_add_hdrs)
&& (state->headers_seen & (1 << (state->resent[0] ?
HDR_RESENT_DATE : HDR_DATE))) == 0) {
cleanup_out_format(state, REC_TYPE_NORM, "%sDate: %s",
state->resent, mail_date(state->arrival_time.tv_sec));
}
/*
* Add a missing (Resent-)From: header.
*/
if ((state->hdr_rewrite_context || var_always_add_hdrs)
&& (state->headers_seen & (1 << (state->resent[0] ?
HDR_RESENT_FROM : HDR_FROM))) == 0) {
quote_822_local(state->temp1, *state->sender ?
state->sender : MAIL_ADDR_MAIL_DAEMON);
if (*state->sender && state->fullname && *state->fullname) {
char *cp;
/* Enforce some sanity on full name content. */
while ((cp = strchr(state->fullname, '\r')) != 0
|| (cp = strchr(state->fullname, '\n')) != 0)
*cp = ' ';
/*
* "From: phrase <route-addr>". Quote the phrase if it contains
* specials or the "%!" legacy address operators.
*/
if (cleanup_hfrom_format == HFROM_FORMAT_CODE_STD) {
vstring_sprintf(state->temp2, "%sFrom: ", state->resent);
if (state->fullname[strcspn(state->fullname,
"%!" LEX_822_SPECIALS)] == 0) {
/* Normalize whitespace. */
token = tok822_scan_limit(state->fullname, &dummy_token,
var_token_limit);
} else {
token = tok822_alloc(TOK822_QSTRING, state->fullname);
}
if (token) {
tok822_externalize(state->temp2, token, TOK822_STR_NONE);
tok822_free(token);
vstring_strcat(state->temp2, " ");
}
vstring_sprintf_append(state->temp2, "<%s>",
vstring_str(state->temp1));
}
/*
* "From: addr-spec (ctext)". This is the obsolete form.
*/
else {
vstring_sprintf(state->temp2, "%sFrom: %s ",
state->resent, vstring_str(state->temp1));
vstring_sprintf(state->temp1, "(%s)", state->fullname);
token = tok822_parse(vstring_str(state->temp1));
tok822_externalize(state->temp2, token, TOK822_STR_NONE);
tok822_free_tree(token);
}
}
/*
* "From: addr-spec". This is the form in the absence of full name
* information, also used for mail from mailer-daemon.
*/
else {
vstring_sprintf(state->temp2, "%sFrom: %s",
state->resent, vstring_str(state->temp1));
}
CLEANUP_OUT_BUF(state, REC_TYPE_NORM, state->temp2);
}
/*
* XXX 2821: Appendix B: The return address in the MAIL command SHOULD,
* if possible, be derived from the system's identity for the submitting
* (local) user, and the "From:" header field otherwise. If there is a
* system identity available, it SHOULD also be copied to the Sender
* header field if it is different from the address in the From header
* field. (Any Sender field that was already there SHOULD be removed.)
* Similar wording appears in RFC 2822 section 3.6.2.
*
* Postfix presently does not insert a Sender: header if envelope and From:
* address differ. Older Postfix versions assumed that the envelope
* sender address specifies the system identity and inserted Sender:
* whenever envelope and From: differed. This was wrong with relayed
* mail, and was often not even desirable with original submissions.
*
* XXX 2822 Section 3.6.2, as well as RFC 822 Section 4.1: FROM headers can
* contain multiple addresses. If this is the case, then a Sender: header
* must be provided with a single address.
*
* Postfix does not count the number of addresses in a From: header
* (although doing so is trivial, once the address is parsed).
*/
/*
* Add a missing destination header.
*/
#define VISIBLE_RCPT ((1 << HDR_TO) | (1 << HDR_RESENT_TO) \
| (1 << HDR_CC) | (1 << HDR_RESENT_CC))
if ((state->hdr_rewrite_context || var_always_add_hdrs)
&& (state->headers_seen & VISIBLE_RCPT) == 0 && *var_rcpt_witheld) {
if (!is_header(var_rcpt_witheld)) {
msg_warn("bad %s header text \"%s\" -- "
"need \"headername: headervalue\"",
VAR_RCPT_WITHELD, var_rcpt_witheld);
} else {
cleanup_out_format(state, REC_TYPE_NORM, "%s", var_rcpt_witheld);
}
}
/*
* Place a dummy PTR record right after the last header so that we can
* append headers without having to worry about clobbering the
* end-of-content marker.
*/
if (state->milters || cleanup_milters) {
if ((state->append_hdr_pt_offset = vstream_ftell(state->dst)) < 0)
msg_fatal("%s: vstream_ftell %s: %m", myname, cleanup_path);
cleanup_out_format(state, REC_TYPE_PTR, REC_TYPE_PTR_FORMAT, 0L);
if ((state->append_hdr_pt_target = vstream_ftell(state->dst)) < 0)
msg_fatal("%s: vstream_ftell %s: %m", myname, cleanup_path);
state->body_offset = state->append_hdr_pt_target;
}
}
/* cleanup_body_callback - output one body record */
static void cleanup_body_callback(void *context, int type,
const char *buf, ssize_t len,
off_t offset)
{
CLEANUP_STATE *state = (CLEANUP_STATE *) context;
/*
* XXX Workaround: when we reach the end of headers, mime_state_update()
* may execute up to three call-backs before returning to the caller:
* head_out(), head_end(), and body_out() or body_end(). As long as
* call-backs don't return a result, each call-back has to check for
* itself if the previous call-back experienced a problem.
*/
if (CLEANUP_OUT_OK(state) == 0)
return;
/*
* Crude message body content filter for emergencies. This code has
* several problems: it sees one line at a time; it looks at long lines
* only in chunks of line_length_limit (2048) characters; it is easily
* bypassed with encodings and other tricks.
*/
if ((state->flags & CLEANUP_FLAG_FILTER)
&& cleanup_body_checks
&& (var_body_check_len == 0 || offset < var_body_check_len)) {
const char *value;
if ((value = maps_find(cleanup_body_checks, buf, 0)) != 0) {
const char *result;
if ((result = cleanup_act(state, CLEANUP_ACT_CTXT_BODY,
buf, value, VAR_BODY_CHECKS))
== CLEANUP_ACT_DROP) {
return;
} else if (result != buf) {
cleanup_out(state, type, result, strlen(result));
myfree((void *) result);
return;
}
} else if (cleanup_body_checks->error) {
msg_warn("%s: %s map lookup problem -- "
"message not accepted, try again later",
state->queue_id, cleanup_body_checks->title);
state->errs |= CLEANUP_STAT_WRITE;
}
}
cleanup_out(state, type, buf, len);
}
/* cleanup_message_headerbody - process message content, header and body */
static void cleanup_message_headerbody(CLEANUP_STATE *state, int type,
const char *buf, ssize_t len)
{
const char *myname = "cleanup_message_headerbody";
const MIME_STATE_DETAIL *detail;
const char *cp;
char *dst;
/*
* Replace each stray CR or LF with one space. These are not allowed in
* SMTP, and can be used to enable outbound (remote) SMTP smuggling.
* Replacing these early ensures that our later DKIM etc. signature will
* not be invalidated. Besides preventing SMTP smuggling, replacing stray
* <CR> or <LF> ensures that the result of signature validation by a
* later mail system will not depend on how that mail system handles
* those stray characters in an implementation-dependent manner.
*
* The input length is not changed, therefore it is safe to overwrite the
* input.
*/
if (var_cleanup_mask_stray_cr_lf)
for (dst = (char *) buf; dst < buf + len; dst++)
if (*dst == '\r' || *dst == '\n')
*dst = ' ';
/*
* Reject unwanted characters.
*
* XXX Possible optimization: simplify the loop when the "reject" set
* contains only one character.
*/
if ((state->flags & CLEANUP_FLAG_FILTER) && cleanup_reject_chars) {
for (cp = buf; cp < buf + len; cp++) {
if (memchr(vstring_str(cleanup_reject_chars),
*(const unsigned char *) cp,
VSTRING_LEN(cleanup_reject_chars))) {
cleanup_act(state, CLEANUP_ACT_CTXT_ANY,
buf, "REJECT disallowed character",
"character reject");
return;
}
}
}
/*
* Strip unwanted characters. Don't overwrite the input.
*
* XXX Possible space+time optimization: use a bitset.
*
* XXX Possible optimization: simplify the loop when the "strip" set
* contains only one character.
*
* XXX Possible optimization: copy the input only if we really have to.
*/
if ((state->flags & CLEANUP_FLAG_FILTER) && cleanup_strip_chars) {
VSTRING_RESET(state->stripped_buf);
VSTRING_SPACE(state->stripped_buf, len + 1);
dst = vstring_str(state->stripped_buf);
for (cp = buf; cp < buf + len; cp++)
if (!memchr(vstring_str(cleanup_strip_chars),
*(const unsigned char *) cp,
VSTRING_LEN(cleanup_strip_chars)))
*dst++ = *cp;
*dst = 0;
buf = vstring_str(state->stripped_buf);
len = dst - buf;
}
/*
* Copy text record to the output.
*/
if (type == REC_TYPE_NORM || type == REC_TYPE_CONT) {
state->mime_errs = mime_state_update(state->mime_state, type, buf, len);
}
/*
* If we have reached the end of the message content segment, record the
* current file position so we can compute the message size lateron.
*/
else if (type == REC_TYPE_XTRA) {
state->mime_errs = mime_state_update(state->mime_state, type, buf, len);
if (state->milters || cleanup_milters)
/* Make room for body modification. */
cleanup_out_format(state, REC_TYPE_PTR, REC_TYPE_PTR_FORMAT, 0L);
/* Ignore header truncation after primary message headers. */
state->mime_errs &= ~MIME_ERR_TRUNC_HEADER;
if (state->mime_errs && state->reason == 0) {
state->errs |= CLEANUP_STAT_CONT;
detail = mime_state_detail(state->mime_errs);
state->reason = dsn_prepend(detail->dsn, detail->text);
}
state->mime_state = mime_state_free(state->mime_state);
if ((state->xtra_offset = vstream_ftell(state->dst)) < 0)
msg_fatal("%s: vstream_ftell %s: %m", myname, cleanup_path);
state->cont_length = state->xtra_offset - state->data_offset;
state->action = cleanup_extracted;
}
/*
* This should never happen.
*/
else {
msg_warn("%s: message rejected: "
"unexpected record type %d in message content", myname, type);
state->errs |= CLEANUP_STAT_BAD;
}
}
/* cleanup_mime_error_callback - error report call-back routine */
static void cleanup_mime_error_callback(void *context, int err_code,
const char *text, ssize_t len)
{
CLEANUP_STATE *state = (CLEANUP_STATE *) context;
const char *origin;
/*
* Message header too large errors are handled after the end of the
* primary message headers.
*/
if ((err_code & ~MIME_ERR_TRUNC_HEADER) != 0) {
if ((origin = nvtable_find(state->attr, MAIL_ATTR_LOG_ORIGIN)) == 0)
origin = MAIL_ATTR_ORG_NONE;
#define TEXT_LEN (len < 100 ? (int) len : 100)
msg_info("%s: reject: mime-error %s: %.*s from %s; from=<%s> to=<%s>",
state->queue_id, mime_state_error(err_code), TEXT_LEN, text,
origin, info_log_addr_form_sender(state->sender),
info_log_addr_form_recipient(state->recip ?
state->recip : "unknown"));
}
}
/* cleanup_message - initialize message content segment */
void cleanup_message(CLEANUP_STATE *state, int type, const char *buf, ssize_t len)
{
const char *myname = "cleanup_message";
int mime_options;
/*
* Write the start-of-content segment marker.
*/
cleanup_out_string(state, REC_TYPE_MESG, "");
if ((state->data_offset = vstream_ftell(state->dst)) < 0)
msg_fatal("%s: vstream_ftell %s: %m", myname, cleanup_path);
/*
* Set up MIME processing options, if any. MIME_OPT_DISABLE_MIME disables
* special processing of Content-Type: headers, and thus, causes all text
* after the primary headers to be treated as the message body.
*/
mime_options = 0;
if (var_disable_mime_input) {
if (var_force_mime_iconv)
msg_fatal("do not specify both %s=yes and %s=yes",
VAR_DISABLE_MIME_INPUT, VAR_FORCE_MIME_ICONV);
mime_options |= MIME_OPT_DISABLE_MIME;
} else {
/* Turn off content checks if bouncing or forwarding mail. */
if (state->flags & CLEANUP_FLAG_FILTER) {
if (var_strict_8bitmime || var_strict_7bit_hdrs)
mime_options |= MIME_OPT_REPORT_8BIT_IN_HEADER;
if (var_strict_8bitmime || var_strict_8bit_body)
mime_options |= MIME_OPT_REPORT_8BIT_IN_7BIT_BODY;
if (var_strict_encoding)
mime_options |= MIME_OPT_REPORT_ENCODING_DOMAIN;
if (var_strict_8bitmime || var_strict_7bit_hdrs
|| var_strict_8bit_body || var_strict_encoding
|| *var_header_checks || *var_mimehdr_checks
|| *var_nesthdr_checks)
mime_options |= MIME_OPT_REPORT_NESTING;
}
if (var_force_mime_iconv)
mime_options |= MIME_OPT_DOWNGRADE;
}
state->mime_state = mime_state_alloc(mime_options,
cleanup_header_callback,
cleanup_header_done_callback,
cleanup_body_callback,
(MIME_STATE_ANY_END) 0,
cleanup_mime_error_callback,
(void *) state);
/*
* XXX Workaround: truncate a long message header so that we don't exceed
* the default Sendmail libmilter request size limit of 65535.
*/
#define KLUDGE_HEADER_LIMIT 60000
if ((cleanup_milters || state->milters)
&& var_header_limit > KLUDGE_HEADER_LIMIT)
var_header_limit = KLUDGE_HEADER_LIMIT;
/*
* Pass control to the header processing routine.
*/
state->action = cleanup_message_headerbody;
cleanup_message_headerbody(state, type, buf, len);
}
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