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main.c
522 lines (473 loc) · 14.2 KB
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main.c
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/* Copyright (c) 2005-2018 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "lib-signals.h"
#include "ioloop.h"
#include "env-util.h"
#include "istream.h"
#include "istream-seekable.h"
#include "path-util.h"
#include "safe-mkstemp.h"
#include "eacces-error.h"
#include "ipwd.h"
#include "str.h"
#include "str-sanitize.h"
#include "strescape.h"
#include "unichar.h"
#include "rfc822-parser.h"
#include "message-address.h"
#include "smtp-address.h"
#include "settings-parser.h"
#include "master-service.h"
#include "master-service-settings.h"
#include "mail-storage-service.h"
#include "mail-namespace.h"
#include "raw-storage.h"
#include "mail-deliver.h"
#include "mail-send.h"
#include "mbox-from.h"
#include "smtp-submit-settings.h"
#include "lda-settings.h"
#include <stdio.h>
#include <sysexits.h>
#define DEFAULT_ENVELOPE_SENDER \
SMTP_ADDRESS_LITERAL("MAILER-DAEMON", NULL)
/* After buffer grows larger than this, create a temporary file to /tmp
where to read the mail. */
#define MAIL_MAX_MEMORY_BUFFER (1024*128)
static const char *wanted_headers[] = {
"From", "To", "Message-ID", "Subject", "Return-Path",
NULL
};
static int seekable_fd_callback(const char **path_r, void *context)
{
struct mail_deliver_context *ctx = context;
string_t *path;
int fd;
path = t_str_new(128);
mail_user_set_get_temp_prefix(path, ctx->rcpt_user->set);
fd = safe_mkstemp(path, 0600, (uid_t)-1, (gid_t)-1);
if (fd == -1) {
i_error("safe_mkstemp(%s) failed: %m", str_c(path));
return -1;
}
/* we just want the fd, unlink it */
if (i_unlink(str_c(path)) < 0) {
/* shouldn't happen.. */
i_close_fd(&fd);
return -1;
}
*path_r = str_c(path);
return fd;
}
static struct istream *
create_raw_stream(struct mail_deliver_context *ctx,
int fd, time_t *mtime_r)
{
struct istream *input, *input2, *input_list[2];
const unsigned char *data;
const char *error;
char *sender = NULL;
size_t i, size;
int ret, tz;
*mtime_r = (time_t)-1;
fd_set_nonblock(fd, FALSE);
input = i_stream_create_fd(fd, 4096);
input->blocking = TRUE;
/* If input begins with a From-line, drop it */
ret = i_stream_read_bytes(input, &data, &size, 5);
if (ret > 0 && memcmp(data, "From ", 5) == 0) {
/* skip until the first LF */
i_stream_skip(input, 5);
while (i_stream_read_more(input, &data, &size) > 0) {
for (i = 0; i < size; i++) {
if (data[i] == '\n')
break;
}
if (i != size) {
(void)mbox_from_parse(data, i, mtime_r, &tz,
&sender);
i_stream_skip(input, i + 1);
break;
}
i_stream_skip(input, size);
}
}
if (sender != NULL && ctx->mail_from == NULL) {
struct smtp_address *mail_from = NULL;
/* use the envelope sender from From_-line, but only if it
hasn't been specified with -f already. */
if (smtp_address_parse_mailbox(ctx->pool,
sender, 0, &mail_from, &error) < 0) {
i_warning("Failed to parse address from `From_'-line: %s",
error);
}
ctx->mail_from = mail_from;
}
i_free(sender);
if (input->v_offset == 0) {
input2 = input;
i_stream_ref(input2);
} else {
input2 = i_stream_create_limit(input, (uoff_t)-1);
}
i_stream_unref(&input);
input_list[0] = input2; input_list[1] = NULL;
input = i_stream_create_seekable(input_list, MAIL_MAX_MEMORY_BUFFER,
seekable_fd_callback, ctx);
i_stream_unref(&input2);
return input;
}
static struct mail *
lda_raw_mail_open(struct mail_deliver_context *ctx, const char *path)
{
struct mail_user *raw_mail_user;
struct mailbox *box;
struct mailbox_transaction_context *t;
struct mail *mail;
struct mailbox_header_lookup_ctx *headers_ctx;
const struct smtp_address *mail_from;
struct istream *input;
void **sets;
time_t mtime;
int ret;
sets = master_service_settings_get_others(master_service);
raw_mail_user =
raw_storage_create_from_set(ctx->rcpt_user->set_info, sets[0]);
mail_from = ctx->mail_from != NULL ?
ctx->mail_from : DEFAULT_ENVELOPE_SENDER;
if (path == NULL) {
input = create_raw_stream(ctx, 0, &mtime);
i_stream_set_name(input, "stdin");
ret = raw_mailbox_alloc_stream(raw_mail_user, input, mtime,
smtp_address_encode(mail_from), &box);
i_stream_unref(&input);
} else {
ret = raw_mailbox_alloc_path(raw_mail_user, path, (time_t)-1,
smtp_address_encode(mail_from), &box);
}
if (ret < 0) {
i_fatal("Can't open delivery mail as raw: %s",
mailbox_get_last_internal_error(box, NULL));
}
mail_user_unref(&raw_mail_user);
t = mailbox_transaction_begin(box, 0, __func__);
headers_ctx = mailbox_header_lookup_init(box, wanted_headers);
mail = mail_alloc(t, 0, headers_ctx);
mailbox_header_lookup_unref(&headers_ctx);
mail_set_seq(mail, 1);
return mail;
}
static void
lda_set_rcpt_to(struct mail_deliver_context *ctx,
const struct smtp_address *rcpt_to, const char *user,
const char *rcpt_to_source)
{
const char *error;
if (rcpt_to == NULL &&
*ctx->set->lda_original_recipient_header != '\0') {
rcpt_to = mail_deliver_get_address(ctx->src_mail,
ctx->set->lda_original_recipient_header);
rcpt_to_source = t_strconcat(
ctx->set->lda_original_recipient_header, " header", NULL);
}
if (rcpt_to == NULL) {
struct smtp_address *user_addr;
if (smtp_address_parse_username(ctx->pool, user,
&user_addr, &error) < 0) {
i_fatal_status(EX_USAGE,
"Cannot obtain SMTP address from username `%s': %s",
user, error);
}
if (user_addr->domain == NULL)
user_addr->domain = ctx->set->hostname;
rcpt_to = user_addr;
rcpt_to_source = "user@hostname";
}
ctx->rcpt_params.orcpt.addr = rcpt_to;
if (ctx->rcpt_to == NULL)
ctx->rcpt_to = rcpt_to;
e_debug(ctx->rcpt_user->event,
"Destination address: %s (source: %s)",
smtp_address_encode_path(rcpt_to), rcpt_to_source);
}
static void failure_exit_callback(int *status)
{
/* we want all our exit codes to be sysexits.h compatible.
if we failed because of a logging related error, we most likely
aren't writing to stderr, so try writing there to give some kind of
a clue what's wrong. FATAL_LOGOPEN failure already wrote to
stderr, so don't duplicate it. */
switch (*status) {
case FATAL_LOGWRITE:
fputs("Failed to write to log file", stderr);
break;
case FATAL_LOGERROR:
fputs("Internal logging error", stderr);
break;
case FATAL_LOGOPEN:
case FATAL_OUTOFMEM:
case FATAL_EXEC:
case FATAL_DEFAULT:
break;
default:
return;
}
*status = EX_TEMPFAIL;
}
static void print_help(void)
{
printf(
"Usage: dovecot-lda [-c <config file>] [-d <username>] [-p <path>]\n"
" [-m <mailbox>] [-e] [-k] [-f <envelope sender>]\n"
" [-a <original envelope recipient>]\n"
" [-r <final envelope recipient>] \n");
}
int main(int argc, char *argv[])
{
const struct setting_parser_info *set_roots[] = {
&smtp_submit_setting_parser_info,
&lda_setting_parser_info,
NULL
};
struct mail_deliver_context ctx;
enum mail_storage_service_flags service_flags = 0;
const char *user, *errstr, *path;
struct lda_settings *lda_set;
struct smtp_submit_settings *smtp_set;
struct smtp_address *rcpt_to, *final_rcpt_to, *mail_from;
struct mail_storage_service_ctx *storage_service;
struct mail_storage_service_user *service_user;
struct mail_storage_service_input service_input;
const struct var_expand_table *var_table;
struct mail_storage *storage;
const char *user_source = "", *rcpt_to_source = "";
uid_t process_euid;
bool stderr_rejection = FALSE;
int ret, c;
enum mail_error error;
if (getuid() != geteuid() && geteuid() == 0) {
/* running setuid - don't allow this if the binary is
executable by anyone */
struct stat st;
if (stat(argv[0], &st) < 0) {
fprintf(stderr, "stat(%s) failed: %s\n",
argv[0], strerror(errno));
return EX_TEMPFAIL;
} else if ((st.st_mode & 1) != 0 && (st.st_mode & 04000) != 0) {
fprintf(stderr, "%s must not be both world-executable "
"and setuid-root. This allows root exploits. "
"See http://wiki2.dovecot.org/LDA#multipleuids\n",
argv[0]);
return EX_TEMPFAIL;
}
}
i_set_failure_exit_callback(failure_exit_callback);
master_service = master_service_init("lda",
MASTER_SERVICE_FLAG_STANDALONE |
MASTER_SERVICE_FLAG_DONT_LOG_TO_STDERR |
MASTER_SERVICE_FLAG_NO_INIT_DATASTACK_FRAME,
&argc, &argv, "a:d:ef:m:p:r:");
i_zero(&ctx);
ctx.session = mail_deliver_session_init();
ctx.pool = ctx.session->pool;
ctx.rcpt_default_mailbox = "INBOX";
path = NULL;
user = getenv("USER");
mail_from = final_rcpt_to = rcpt_to = NULL;
while ((c = master_getopt(master_service)) > 0) {
switch (c) {
case 'a':
/* original recipient address */
if (smtp_address_parse_path(ctx.pool, optarg,
SMTP_ADDRESS_PARSE_FLAG_ALLOW_LOCALPART |
SMTP_ADDRESS_PARSE_FLAG_BRACKETS_OPTIONAL,
&rcpt_to, &errstr) < 0) {
i_fatal_status(EX_USAGE,
"Invalid -a parameter: %s", errstr);
}
rcpt_to_source = "-a parameter";
break;
case 'd':
/* destination user */
user = optarg;
service_flags |= MAIL_STORAGE_SERVICE_FLAG_USERDB_LOOKUP;
break;
case 'e':
stderr_rejection = TRUE;
break;
case 'f':
/* envelope sender address */
if (smtp_address_parse_path(ctx.pool, optarg,
SMTP_ADDRESS_PARSE_FLAG_BRACKETS_OPTIONAL |
SMTP_ADDRESS_PARSE_FLAG_ALLOW_LOCALPART |
SMTP_ADDRESS_PARSE_FLAG_ALLOW_EMPTY,
&mail_from, &errstr) < 0) {
i_fatal_status(EX_USAGE,
"Invalid -f parameter: %s", errstr);
}
break;
case 'm':
/* destination mailbox.
Ignore -m "". This allows doing -m ${extension}
in Postfix to handle user+mailbox */
if (*optarg != '\0') T_BEGIN {
if (!uni_utf8_str_is_valid(optarg)) {
i_fatal("Mailbox name not UTF-8: %s",
optarg);
}
ctx.rcpt_default_mailbox = optarg;
} T_END;
break;
case 'p':
/* input path */
if (t_abspath(optarg, &path, &errstr) < 0) {
i_fatal("t_abspath(%s) failed: %s",
optarg, errstr);
}
break;
case 'r':
/* final recipient address */
if (smtp_address_parse_path(ctx.pool, optarg,
SMTP_ADDRESS_PARSE_FLAG_ALLOW_LOCALPART |
SMTP_ADDRESS_PARSE_FLAG_BRACKETS_OPTIONAL,
&final_rcpt_to, &errstr) < 0) {
i_fatal_status(EX_USAGE,
"Invalid -r parameter: %s", errstr);
}
break;
default:
print_help();
return EX_USAGE;
}
}
if (optind != argc) {
print_help();
i_fatal_status(EX_USAGE, "Unknown argument: %s", argv[optind]);
}
process_euid = geteuid();
if ((service_flags & MAIL_STORAGE_SERVICE_FLAG_USERDB_LOOKUP) != 0)
;
else if (process_euid != 0) {
/* we're non-root. get our username and possibly our home. */
struct passwd pw;
const char *home;
home = getenv("HOME");
if (user != NULL && home != NULL) {
/* no need for a pw lookup */
user_source = "USER environment";
} else if ((ret = i_getpwuid(process_euid, &pw)) > 0) {
user = t_strdup(pw.pw_name);
if (home == NULL)
env_put(t_strconcat("HOME=", pw.pw_dir, NULL));
user_source = "passwd lookup for process euid";
} else if (ret < 0) {
/* temporary failure */
i_fatal("getpwuid() failed: %m");
} else if (user == NULL) {
i_fatal_status(EX_USAGE,
"Couldn't lookup our username (uid=%s)",
dec2str(process_euid));
}
} else {
i_fatal_status(EX_USAGE,
"destination user parameter (-d user) not given");
}
master_service_init_finish(master_service);
i_zero(&service_input);
service_input.module = "lda";
service_input.service = "lda";
service_input.username = user;
service_flags |= MAIL_STORAGE_SERVICE_FLAG_USE_SYSEXITS;
storage_service = mail_storage_service_init(master_service, set_roots,
service_flags);
mail_deliver_hooks_init();
/* set before looking up the user (or ideally we'd do this between
_lookup() and _next(), but don't bother) */
ctx.delivery_time_started = ioloop_timeval;
ret = mail_storage_service_lookup_next(storage_service, &service_input,
&service_user, &ctx.rcpt_user,
&errstr);
if (ret <= 0) {
if (ret < 0)
i_fatal("%s", errstr);
return EX_NOUSER;
}
#ifdef SIGXFSZ
lib_signals_ignore(SIGXFSZ, TRUE);
#endif
if (*user_source != '\0') {
e_debug(ctx.rcpt_user->event,
"userdb lookup skipped, username taken from %s",
user_source);
}
ctx.mail_from = mail_from;
ctx.rcpt_to = final_rcpt_to;
var_table = mail_user_var_expand_table(ctx.rcpt_user);
smtp_set = mail_storage_service_user_get_set(service_user)[1];
lda_set = mail_storage_service_user_get_set(service_user)[2];
ret = settings_var_expand(
&lda_setting_parser_info,
lda_set, ctx.rcpt_user->pool, var_table,
&errstr);
if (ret > 0) {
ret = settings_var_expand(
&smtp_submit_setting_parser_info,
smtp_set, ctx.rcpt_user->pool, var_table,
&errstr);
}
if (ret <= 0)
i_fatal("Failed to expand settings: %s", errstr);
ctx.set = lda_set;
ctx.smtp_set = smtp_set;
ctx.src_mail = lda_raw_mail_open(&ctx, path);
lda_set_rcpt_to(&ctx, rcpt_to, user, rcpt_to_source);
if (mail_deliver(&ctx, &storage) < 0) {
if (ctx.tempfail_error != NULL) {
errstr = ctx.tempfail_error;
error = MAIL_ERROR_TEMP;
} else if (storage != NULL) {
errstr = mail_storage_get_last_error(storage, &error);
} else {
/* This shouldn't happen */
i_error("BUG: Saving failed to unknown storage");
return EX_TEMPFAIL;
}
if (stderr_rejection) {
/* write to stderr also for tempfails so that MTA
can log the reason if it wants to. */
fprintf(stderr, "%s\n", errstr);
}
if (error != MAIL_ERROR_NOQUOTA ||
ctx.set->quota_full_tempfail) {
/* Saving to INBOX should always work unless
we're over quota. If it didn't, it's probably a
configuration problem. */
return EX_TEMPFAIL;
}
ctx.mailbox_full = TRUE;
ctx.dsn = TRUE;
/* we'll have to reply with permanent failure */
mail_deliver_log(&ctx, "rejected: %s",
str_sanitize(errstr, 512));
if (stderr_rejection)
return EX_NOPERM;
ret = mail_send_rejection(&ctx, ctx.rcpt_to, errstr);
if (ret != 0)
return ret < 0 ? EX_TEMPFAIL : ret;
/* ok, rejection sent */
}
{
struct mailbox_transaction_context *t =
ctx.src_mail->transaction;
struct mailbox *box = ctx.src_mail->box;
mail_free(&ctx.src_mail);
mailbox_transaction_rollback(&t);
mailbox_free(&box);
}
mail_user_unref(&ctx.rcpt_user);
mail_deliver_session_deinit(&ctx.session);
mail_storage_service_user_unref(&service_user);
mail_storage_service_deinit(&storage_service);
master_service_deinit(&master_service);
return EX_OK;
}