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Diffstat (limited to 'src/cleanup/cleanup_message.c')
| -rw-r--r-- | src/cleanup/cleanup_message.c | 1111 |
1 files changed, 1111 insertions, 0 deletions
diff --git a/src/cleanup/cleanup_message.c b/src/cleanup/cleanup_message.c new file mode 100644 index 0000000..1ee0a52 --- /dev/null +++ b/src/cleanup/cleanup_message.c @@ -0,0 +1,1111 @@ +/*++ +/* 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) + 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 + * 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->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) { + 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); +} |