Adding upstream version 3.5.24.upstream/3.5.24upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1116 insertions, 0 deletions

diff --git a/src/cleanup/cleanup_message.c b/src/cleanup/cleanup_message.c
new file mode 100644
index 0000000..4284c46
--- /dev/null
+++ b/src/cleanup/cleanup_message.c
@@ -0,0 +1,1116 @@
+/*++
+/* 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>
+
+/* 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)
+	    msg_info("%s: message-id=%s", state->queue_id, hdrval);
+	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
+     * assupmtion 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->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 = ' ';
+
+	    switch (hfrom_format_code) {
+
+		/*
+		 * "From: phrase <route-addr>". Quote the phrase if it
+		 * contains specials or the "%!" legacy address operators.
+		 */
+	    case 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));
+		break;
+
+		/*
+		 * "From: addr-spec (ctext)". This is the obsolete form.
+		 */
+	    case HFROM_FORMAT_CODE_OBS:
+		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);
+		break;
+	    default:
+		msg_panic("%s: unknown header format %d",
+			  myname, hfrom_format_code);
+	    }
+	}
+
+	/*
+	 * "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) {
+	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;
+	}
+    }
+    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);
+}