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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:46:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:46:30 +0000
commitb5896ba9f6047e7031e2bdee0622d543e11a6734 (patch)
treefd7b460593a2fee1be579bec5697e6d887ea3421 /src/tlsmgr/tlsmgr.c
parentInitial commit. (diff)
downloadpostfix-b5896ba9f6047e7031e2bdee0622d543e11a6734.tar.xz
postfix-b5896ba9f6047e7031e2bdee0622d543e11a6734.zip
Adding upstream version 3.4.23.upstream/3.4.23upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/tlsmgr/tlsmgr.c')
-rw-r--r--src/tlsmgr/tlsmgr.c1098
1 files changed, 1098 insertions, 0 deletions
diff --git a/src/tlsmgr/tlsmgr.c b/src/tlsmgr/tlsmgr.c
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+/*++
+/* NAME
+/* tlsmgr 8
+/* SUMMARY
+/* Postfix TLS session cache and PRNG manager
+/* SYNOPSIS
+/* \fBtlsmgr\fR [generic Postfix daemon options]
+/* DESCRIPTION
+/* The \fBtlsmgr\fR(8) manages the Postfix TLS session caches.
+/* It stores and retrieves cache entries on request by
+/* \fBsmtpd\fR(8) and \fBsmtp\fR(8) processes, and periodically
+/* removes entries that have expired.
+/*
+/* The \fBtlsmgr\fR(8) also manages the PRNG (pseudo random number
+/* generator) pool. It answers queries by the \fBsmtpd\fR(8)
+/* and \fBsmtp\fR(8)
+/* processes to seed their internal PRNG pools.
+/*
+/* The \fBtlsmgr\fR(8)'s PRNG pool is initially seeded from
+/* an external source (EGD, /dev/urandom, or regular file).
+/* It is updated at configurable pseudo-random intervals with
+/* data from the external source. It is updated periodically
+/* with data from TLS session cache entries and with the time
+/* of day, and is updated with the time of day whenever a
+/* process requests \fBtlsmgr\fR(8) service.
+/*
+/* The \fBtlsmgr\fR(8) saves the PRNG state to an exchange file
+/* periodically and when the process terminates, and reads
+/* the exchange file when initializing its PRNG.
+/* SECURITY
+/* .ad
+/* .fi
+/* The \fBtlsmgr\fR(8) is not security-sensitive. The code that maintains
+/* the external and internal PRNG pools does not "trust" the
+/* data that it manipulates, and the code that maintains the
+/* TLS session cache does not touch the contents of the cached
+/* entries, except for seeding its internal PRNG pool.
+/*
+/* The \fBtlsmgr\fR(8) can be run chrooted and with reduced privileges.
+/* At process startup it connects to the entropy source and
+/* exchange file, and creates or truncates the optional TLS
+/* session cache files.
+/*
+/* With Postfix version 2.5 and later, the \fBtlsmgr\fR(8) no
+/* longer uses root privileges when opening cache files. These
+/* files should now be stored under the Postfix-owned
+/* \fBdata_directory\fR. As a migration aid, an attempt to
+/* open a cache file under a non-Postfix directory is redirected
+/* to the Postfix-owned \fBdata_directory\fR, and a warning
+/* is logged.
+/* DIAGNOSTICS
+/* Problems and transactions are logged to \fBsyslogd\fR(8)
+/* or \fBpostlogd\fR(8).
+/* BUGS
+/* There is no automatic means to limit the number of entries in the
+/* TLS session caches and/or the size of the TLS cache files.
+/* CONFIGURATION PARAMETERS
+/* .ad
+/* .fi
+/* Changes to \fBmain.cf\fR are not picked up automatically,
+/* because \fBtlsmgr\fR(8) is a persistent processes. Use the
+/* command "\fBpostfix reload\fR" after a configuration change.
+/*
+/* The text below provides only a parameter summary. See
+/* \fBpostconf\fR(5) for more details including examples.
+/* TLS SESSION CACHE
+/* .ad
+/* .fi
+/* .IP "\fBlmtp_tls_loglevel (0)\fR"
+/* The LMTP-specific version of the smtp_tls_loglevel
+/* configuration parameter.
+/* .IP "\fBlmtp_tls_session_cache_database (empty)\fR"
+/* The LMTP-specific version of the smtp_tls_session_cache_database
+/* configuration parameter.
+/* .IP "\fBlmtp_tls_session_cache_timeout (3600s)\fR"
+/* The LMTP-specific version of the smtp_tls_session_cache_timeout
+/* configuration parameter.
+/* .IP "\fBsmtp_tls_loglevel (0)\fR"
+/* Enable additional Postfix SMTP client logging of TLS activity.
+/* .IP "\fBsmtp_tls_session_cache_database (empty)\fR"
+/* Name of the file containing the optional Postfix SMTP client
+/* TLS session cache.
+/* .IP "\fBsmtp_tls_session_cache_timeout (3600s)\fR"
+/* The expiration time of Postfix SMTP client TLS session cache
+/* information.
+/* .IP "\fBsmtpd_tls_loglevel (0)\fR"
+/* Enable additional Postfix SMTP server logging of TLS activity.
+/* .IP "\fBsmtpd_tls_session_cache_database (empty)\fR"
+/* Name of the file containing the optional Postfix SMTP server
+/* TLS session cache.
+/* .IP "\fBsmtpd_tls_session_cache_timeout (3600s)\fR"
+/* The expiration time of Postfix SMTP server TLS session cache
+/* information.
+/* PSEUDO RANDOM NUMBER GENERATOR
+/* .ad
+/* .fi
+/* .IP "\fBtls_random_source (see 'postconf -d' output)\fR"
+/* The external entropy source for the in-memory \fBtlsmgr\fR(8) pseudo
+/* random number generator (PRNG) pool.
+/* .IP "\fBtls_random_bytes (32)\fR"
+/* The number of bytes that \fBtlsmgr\fR(8) reads from $tls_random_source
+/* when (re)seeding the in-memory pseudo random number generator (PRNG)
+/* pool.
+/* .IP "\fBtls_random_exchange_name (see 'postconf -d' output)\fR"
+/* Name of the pseudo random number generator (PRNG) state file
+/* that is maintained by \fBtlsmgr\fR(8).
+/* .IP "\fBtls_random_prng_update_period (3600s)\fR"
+/* The time between attempts by \fBtlsmgr\fR(8) to save the state of
+/* the pseudo random number generator (PRNG) to the file specified
+/* with $tls_random_exchange_name.
+/* .IP "\fBtls_random_reseed_period (3600s)\fR"
+/* The maximal time between attempts by \fBtlsmgr\fR(8) to re-seed the
+/* in-memory pseudo random number generator (PRNG) pool from external
+/* sources.
+/* MISCELLANEOUS CONTROLS
+/* .ad
+/* .fi
+/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
+/* The default location of the Postfix main.cf and master.cf
+/* configuration files.
+/* .IP "\fBdata_directory (see 'postconf -d' output)\fR"
+/* The directory with Postfix-writable data files (for example:
+/* caches, pseudo-random numbers).
+/* .IP "\fBdaemon_timeout (18000s)\fR"
+/* How much time a Postfix daemon process may take to handle a
+/* request before it is terminated by a built-in watchdog timer.
+/* .IP "\fBprocess_id (read-only)\fR"
+/* The process ID of a Postfix command or daemon process.
+/* .IP "\fBprocess_name (read-only)\fR"
+/* The process name of a Postfix command or daemon process.
+/* .IP "\fBsyslog_facility (mail)\fR"
+/* The syslog facility of Postfix logging.
+/* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
+/* A prefix that is prepended to the process name in syslog
+/* records, so that, for example, "smtpd" becomes "prefix/smtpd".
+/* .PP
+/* Available in Postfix 3.3 and later:
+/* .IP "\fBservice_name (read-only)\fR"
+/* The master.cf service name of a Postfix daemon process.
+/* SEE ALSO
+/* smtp(8), Postfix SMTP client
+/* smtpd(8), Postfix SMTP server
+/* postconf(5), configuration parameters
+/* master(5), generic daemon options
+/* master(8), process manager
+/* postlogd(8), Postfix logging
+/* syslogd(8), system logging
+/* README FILES
+/* .ad
+/* .fi
+/* Use "\fBpostconf readme_directory\fR" or
+/* "\fBpostconf html_directory\fR" to locate this information.
+/* .na
+/* .nf
+/* TLS_README, Postfix TLS configuration and operation
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* HISTORY
+/* This service was introduced with Postfix version 2.2.
+/* AUTHOR(S)
+/* Lutz Jaenicke
+/* BTU Cottbus
+/* Allgemeine Elektrotechnik
+/* Universitaetsplatz 3-4
+/* D-03044 Cottbus, Germany
+/*
+/* Adapted by:
+/* 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 <sys/stat.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/time.h> /* gettimeofday, not POSIX */
+#include <limits.h>
+
+#ifndef UCHAR_MAX
+#define UCHAR_MAX 0xff
+#endif
+
+/* OpenSSL library. */
+
+#ifdef USE_TLS
+#include <openssl/rand.h> /* For the PRNG */
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <events.h>
+#include <stringops.h>
+#include <mymalloc.h>
+#include <iostuff.h>
+#include <vstream.h>
+#include <vstring.h>
+#include <vstring_vstream.h>
+#include <attr.h>
+#include <set_eugid.h>
+#include <htable.h>
+#include <warn_stat.h>
+
+/* Global library. */
+
+#include <mail_conf.h>
+#include <mail_params.h>
+#include <mail_version.h>
+#include <mail_proto.h>
+#include <data_redirect.h>
+
+/* Master process interface. */
+
+#include <master_proto.h>
+#include <mail_server.h>
+
+/* TLS library. */
+
+#ifdef USE_TLS
+#include <tls_mgr.h>
+#define TLS_INTERNAL
+#include <tls.h> /* TLS_MGR_SCACHE_<type> */
+#include <tls_prng.h>
+#include <tls_scache.h>
+
+/* Application-specific. */
+
+ /*
+ * Tunables.
+ */
+char *var_tls_rand_source;
+int var_tls_rand_bytes;
+int var_tls_reseed_period;
+int var_tls_prng_exch_period;
+char *var_smtpd_tls_loglevel;
+char *var_smtpd_tls_scache_db;
+int var_smtpd_tls_scache_timeout;
+char *var_smtp_tls_loglevel;
+char *var_smtp_tls_scache_db;
+int var_smtp_tls_scache_timeout;
+char *var_lmtp_tls_loglevel;
+char *var_lmtp_tls_scache_db;
+int var_lmtp_tls_scache_timeout;
+char *var_tls_rand_exch_name;
+
+ /*
+ * Bound the time that we are willing to wait for an I/O operation. This
+ * produces better error messages than waiting until the watchdog timer
+ * kills the process.
+ */
+#define TLS_MGR_TIMEOUT 10
+
+ /*
+ * State for updating the PRNG exchange file.
+ */
+static TLS_PRNG_SRC *rand_exch;
+
+ /*
+ * State for seeding the internal PRNG from external source.
+ */
+static TLS_PRNG_SRC *rand_source_dev;
+static TLS_PRNG_SRC *rand_source_egd;
+static TLS_PRNG_SRC *rand_source_file;
+
+ /*
+ * The external entropy source type is encoded in the source name. The
+ * obvious alternative is to have separate configuration parameters per
+ * source type, so that one process can query multiple external sources.
+ */
+#define DEV_PREF "dev:"
+#define DEV_PREF_LEN (sizeof((DEV_PREF)) - 1)
+#define DEV_PATH(dev) ((dev) + EGD_PREF_LEN)
+
+#define EGD_PREF "egd:"
+#define EGD_PREF_LEN (sizeof((EGD_PREF)) - 1)
+#define EGD_PATH(egd) ((egd) + EGD_PREF_LEN)
+
+ /*
+ * State for TLS session caches.
+ */
+typedef struct {
+ char *cache_label; /* cache short-hand name */
+ TLS_SCACHE *cache_info; /* cache handle */
+ int cache_active; /* cache status */
+ char **cache_db; /* main.cf parameter value */
+ const char *log_param; /* main.cf parameter name */
+ char **log_level; /* main.cf parameter value */
+ int *cache_timeout; /* main.cf parameter value */
+} TLSMGR_SCACHE;
+
+static TLSMGR_SCACHE cache_table[] = {
+ TLS_MGR_SCACHE_SMTPD, 0, 0, &var_smtpd_tls_scache_db,
+ VAR_SMTPD_TLS_LOGLEVEL,
+ &var_smtpd_tls_loglevel, &var_smtpd_tls_scache_timeout,
+ TLS_MGR_SCACHE_SMTP, 0, 0, &var_smtp_tls_scache_db,
+ VAR_SMTP_TLS_LOGLEVEL,
+ &var_smtp_tls_loglevel, &var_smtp_tls_scache_timeout,
+ TLS_MGR_SCACHE_LMTP, 0, 0, &var_lmtp_tls_scache_db,
+ VAR_LMTP_TLS_LOGLEVEL,
+ &var_lmtp_tls_loglevel, &var_lmtp_tls_scache_timeout,
+ 0,
+};
+
+#define smtpd_cache (cache_table[0])
+
+ /*
+ * SLMs.
+ */
+#define STR(x) vstring_str(x)
+#define LEN(x) VSTRING_LEN(x)
+#define STREQ(x, y) (strcmp((x), (y)) == 0)
+
+/* tlsmgr_prng_exch_event - update PRNG exchange file */
+
+static void tlsmgr_prng_exch_event(int unused_event, void *dummy)
+{
+ const char *myname = "tlsmgr_prng_exch_event";
+ unsigned char randbyte;
+ int next_period;
+ struct stat st;
+
+ if (msg_verbose)
+ msg_info("%s: update PRNG exchange file", myname);
+
+ /*
+ * Sanity check. If the PRNG exchange file was removed, there is no point
+ * updating it further. Restart the process and update the new file.
+ */
+ if (fstat(rand_exch->fd, &st) < 0)
+ msg_fatal("cannot fstat() the PRNG exchange file: %m");
+ if (st.st_nlink == 0) {
+ msg_warn("PRNG exchange file was removed -- exiting to reopen");
+ sleep(1);
+ exit(0);
+ }
+ tls_prng_exch_update(rand_exch);
+
+ /*
+ * Make prediction difficult for outsiders and calculate the time for the
+ * next execution randomly.
+ */
+ RAND_bytes(&randbyte, 1);
+ next_period = (var_tls_prng_exch_period * randbyte) / UCHAR_MAX;
+ event_request_timer(tlsmgr_prng_exch_event, dummy, next_period);
+}
+
+/* tlsmgr_reseed_event - re-seed the internal PRNG pool */
+
+static void tlsmgr_reseed_event(int unused_event, void *dummy)
+{
+ int next_period;
+ unsigned char randbyte;
+ int must_exit = 0;
+
+ /*
+ * Reseed the internal PRNG from external source. Errors are recoverable.
+ * We simply restart and reconnect without making a fuss. This is OK
+ * because we do require that exchange file updates succeed. The exchange
+ * file is the only entropy source that really matters in the long term.
+ *
+ * If the administrator specifies an external randomness source that we
+ * could not open upon start-up, restart to see if we can open it now
+ * (and log a nagging warning if we can't).
+ */
+ if (*var_tls_rand_source) {
+
+ /*
+ * Source is a random device.
+ */
+ if (rand_source_dev) {
+ if (tls_prng_dev_read(rand_source_dev, var_tls_rand_bytes) <= 0) {
+ msg_info("cannot read from entropy device %s: %m -- "
+ "exiting to reopen", DEV_PATH(var_tls_rand_source));
+ must_exit = 1;
+ }
+ }
+
+ /*
+ * Source is an EGD compatible socket.
+ */
+ else if (rand_source_egd) {
+ if (tls_prng_egd_read(rand_source_egd, var_tls_rand_bytes) <= 0) {
+ msg_info("lost connection to EGD server %s -- "
+ "exiting to reconnect", EGD_PATH(var_tls_rand_source));
+ must_exit = 1;
+ }
+ }
+
+ /*
+ * Source is a regular file. Read the content once and close the
+ * file.
+ */
+ else if (rand_source_file) {
+ if (tls_prng_file_read(rand_source_file, var_tls_rand_bytes) <= 0)
+ msg_warn("cannot read from entropy file %s: %m",
+ var_tls_rand_source);
+ tls_prng_file_close(rand_source_file);
+ rand_source_file = 0;
+ var_tls_rand_source[0] = 0;
+ }
+
+ /*
+ * Could not open the external source upon start-up. See if we can
+ * open it this time. Save PRNG state before we exit.
+ */
+ else {
+ msg_info("exiting to reopen external entropy source %s",
+ var_tls_rand_source);
+ must_exit = 1;
+ }
+ }
+
+ /*
+ * Save PRNG state in case we must exit.
+ */
+ if (must_exit) {
+ if (rand_exch)
+ tls_prng_exch_update(rand_exch);
+ sleep(1);
+ exit(0);
+ }
+
+ /*
+ * Make prediction difficult for outsiders and calculate the time for the
+ * next execution randomly.
+ */
+ RAND_bytes(&randbyte, 1);
+ next_period = (var_tls_reseed_period * randbyte) / UCHAR_MAX;
+ event_request_timer(tlsmgr_reseed_event, dummy, next_period);
+}
+
+/* tlsmgr_cache_run_event - start TLS session cache scan */
+
+static void tlsmgr_cache_run_event(int unused_event, void *ctx)
+{
+ const char *myname = "tlsmgr_cache_run_event";
+ TLSMGR_SCACHE *cache = (TLSMGR_SCACHE *) ctx;
+
+ /*
+ * This routine runs when it is time for another TLS session cache scan.
+ * Make sure this routine gets called again in the future.
+ *
+ * Don't start a new scan when the timer goes off while cache cleanup is
+ * still in progress.
+ */
+ if (cache->cache_info->verbose)
+ msg_info("%s: start TLS %s session cache cleanup",
+ myname, cache->cache_label);
+
+ if (cache->cache_active == 0)
+ cache->cache_active =
+ tls_scache_sequence(cache->cache_info, DICT_SEQ_FUN_FIRST,
+ TLS_SCACHE_SEQUENCE_NOTHING);
+
+ event_request_timer(tlsmgr_cache_run_event, (void *) cache,
+ cache->cache_info->timeout);
+}
+
+/* tlsmgr_key - return matching or current RFC 5077 session ticket keys */
+
+static int tlsmgr_key(VSTRING *buffer, int timeout)
+{
+ TLS_TICKET_KEY *key;
+ TLS_TICKET_KEY tmp;
+ unsigned char *name;
+ time_t now = time((time_t *) 0);
+
+ /* In tlsmgr requests we encode null key names as empty strings. */
+ name = LEN(buffer) ? (unsigned char *) STR(buffer) : 0;
+
+ /*
+ * Each key's encrypt and subsequent decrypt-only timeout is half of the
+ * total session timeout.
+ */
+ timeout /= 2;
+
+ /* Attempt to locate existing key */
+ if ((key = tls_scache_key(name, now, timeout)) == 0) {
+ if (name == 0) {
+ /* Create new encryption key */
+ if (RAND_bytes(tmp.name, TLS_TICKET_NAMELEN) <= 0
+ || RAND_bytes(tmp.bits, TLS_TICKET_KEYLEN) <= 0
+ || RAND_bytes(tmp.hmac, TLS_TICKET_MACLEN) <= 0)
+ return (TLS_MGR_STAT_ERR);
+ tmp.tout = now + timeout - 1;
+ key = tls_scache_key_rotate(&tmp);
+ } else {
+ /* No matching decryption key found */
+ return (TLS_MGR_STAT_ERR);
+ }
+ }
+ /* Return value overrites name buffer */
+ vstring_memcpy(buffer, (char *) key, sizeof(*key));
+ return (TLS_MGR_STAT_OK);
+}
+
+/* tlsmgr_loop - TLS manager main loop */
+
+static int tlsmgr_loop(char *unused_name, char **unused_argv)
+{
+ struct timeval tv;
+ int active = 0;
+ TLSMGR_SCACHE *ent;
+
+ /*
+ * Update the PRNG pool with the time of day. We do it here after every
+ * event (including internal timer events and external client request
+ * events), instead of doing it in individual event call-back routines.
+ */
+ GETTIMEOFDAY(&tv);
+ RAND_seed(&tv, sizeof(struct timeval));
+
+ /*
+ * This routine runs as part of the event handling loop, after the event
+ * manager has delivered a timer or I/O event, or after it has waited for
+ * a specified amount of time. The result value of tlsmgr_loop()
+ * specifies how long the event manager should wait for the next event.
+ *
+ * We use this loop to interleave TLS session cache cleanup with other
+ * activity. Interleaved processing is needed when we use a client-server
+ * protocol for entropy and session state exchange with smtp(8) and
+ * smtpd(8) processes.
+ */
+#define DONT_WAIT 0
+#define WAIT_FOR_EVENT (-1)
+
+ for (ent = cache_table; ent->cache_label; ++ent) {
+ if (ent->cache_info && ent->cache_active)
+ active |= ent->cache_active =
+ tls_scache_sequence(ent->cache_info, DICT_SEQ_FUN_NEXT,
+ TLS_SCACHE_SEQUENCE_NOTHING);
+ }
+
+ return (active ? DONT_WAIT : WAIT_FOR_EVENT);
+}
+
+/* tlsmgr_request_receive - receive request */
+
+static int tlsmgr_request_receive(VSTREAM *client_stream, VSTRING *request)
+{
+ int count;
+
+ /*
+ * Kluge: choose the protocol depending on the request size.
+ */
+ if (read_wait(vstream_fileno(client_stream), var_ipc_timeout) < 0) {
+ msg_warn("timeout while waiting for data from %s",
+ VSTREAM_PATH(client_stream));
+ return (-1);
+ }
+ if ((count = peekfd(vstream_fileno(client_stream))) < 0) {
+ msg_warn("cannot examine read buffer of %s: %m",
+ VSTREAM_PATH(client_stream));
+ return (-1);
+ }
+
+ /*
+ * Short request: master trigger. Use the string+null protocol.
+ */
+ if (count <= 2) {
+ if (vstring_get_null(request, client_stream) == VSTREAM_EOF) {
+ msg_warn("end-of-input while reading request from %s: %m",
+ VSTREAM_PATH(client_stream));
+ return (-1);
+ }
+ }
+
+ /*
+ * Long request: real tlsmgr client. Use the attribute list protocol.
+ */
+ else {
+ if (attr_scan(client_stream,
+ ATTR_FLAG_MORE | ATTR_FLAG_STRICT,
+ RECV_ATTR_STR(TLS_MGR_ATTR_REQ, request),
+ ATTR_TYPE_END) != 1) {
+ return (-1);
+ }
+ }
+ return (0);
+}
+
+/* tlsmgr_service - respond to external request */
+
+static void tlsmgr_service(VSTREAM *client_stream, char *unused_service,
+ char **argv)
+{
+ static VSTRING *request = 0;
+ static VSTRING *cache_type = 0;
+ static VSTRING *cache_id = 0;
+ static VSTRING *buffer = 0;
+ int len;
+ static char wakeup[] = { /* master wakeup request */
+ TRIGGER_REQ_WAKEUP,
+ 0,
+ };
+ TLSMGR_SCACHE *ent;
+ int status = TLS_MGR_STAT_FAIL;
+
+ /*
+ * Sanity check. This service takes no command-line arguments.
+ */
+ if (argv[0])
+ msg_fatal("unexpected command-line argument: %s", argv[0]);
+
+ /*
+ * Initialize. We're select threaded, so we can use static buffers.
+ */
+ if (request == 0) {
+ request = vstring_alloc(10);
+ cache_type = vstring_alloc(10);
+ cache_id = vstring_alloc(10);
+ buffer = vstring_alloc(10);
+ }
+
+ /*
+ * This routine runs whenever a client connects to the socket dedicated
+ * to the tlsmgr service (including wake up events sent by the master).
+ * All connection-management stuff is handled by the common code in
+ * multi_server.c.
+ */
+ if (tlsmgr_request_receive(client_stream, request) == 0) {
+
+ /*
+ * Load session from cache.
+ */
+ if (STREQ(STR(request), TLS_MGR_REQ_LOOKUP)) {
+ if (attr_scan(client_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
+ RECV_ATTR_STR(TLS_MGR_ATTR_CACHE_ID, cache_id),
+ ATTR_TYPE_END) == 2) {
+ for (ent = cache_table; ent->cache_label; ++ent)
+ if (strcmp(ent->cache_label, STR(cache_type)) == 0)
+ break;
+ if (ent->cache_label == 0) {
+ msg_warn("bogus cache type \"%s\" in \"%s\" request",
+ STR(cache_type), TLS_MGR_REQ_LOOKUP);
+ VSTRING_RESET(buffer);
+ } else if (ent->cache_info == 0) {
+
+ /*
+ * Cache type valid, but not enabled
+ */
+ VSTRING_RESET(buffer);
+ } else {
+ status = tls_scache_lookup(ent->cache_info,
+ STR(cache_id), buffer) ?
+ TLS_MGR_STAT_OK : TLS_MGR_STAT_ERR;
+ }
+ }
+ attr_print(client_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_INT(MAIL_ATTR_STATUS, status),
+ SEND_ATTR_DATA(TLS_MGR_ATTR_SESSION,
+ LEN(buffer), STR(buffer)),
+ ATTR_TYPE_END);
+ }
+
+ /*
+ * Save session to cache.
+ */
+ else if (STREQ(STR(request), TLS_MGR_REQ_UPDATE)) {
+ if (attr_scan(client_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
+ RECV_ATTR_STR(TLS_MGR_ATTR_CACHE_ID, cache_id),
+ RECV_ATTR_DATA(TLS_MGR_ATTR_SESSION, buffer),
+ ATTR_TYPE_END) == 3) {
+ for (ent = cache_table; ent->cache_label; ++ent)
+ if (strcmp(ent->cache_label, STR(cache_type)) == 0)
+ break;
+ if (ent->cache_label == 0) {
+ msg_warn("bogus cache type \"%s\" in \"%s\" request",
+ STR(cache_type), TLS_MGR_REQ_UPDATE);
+ } else if (ent->cache_info != 0) {
+ status =
+ tls_scache_update(ent->cache_info, STR(cache_id),
+ STR(buffer), LEN(buffer)) ?
+ TLS_MGR_STAT_OK : TLS_MGR_STAT_ERR;
+ }
+ }
+ attr_print(client_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_INT(MAIL_ATTR_STATUS, status),
+ ATTR_TYPE_END);
+ }
+
+ /*
+ * Delete session from cache.
+ */
+ else if (STREQ(STR(request), TLS_MGR_REQ_DELETE)) {
+ if (attr_scan(client_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
+ RECV_ATTR_STR(TLS_MGR_ATTR_CACHE_ID, cache_id),
+ ATTR_TYPE_END) == 2) {
+ for (ent = cache_table; ent->cache_label; ++ent)
+ if (strcmp(ent->cache_label, STR(cache_type)) == 0)
+ break;
+ if (ent->cache_label == 0) {
+ msg_warn("bogus cache type \"%s\" in \"%s\" request",
+ STR(cache_type), TLS_MGR_REQ_DELETE);
+ } else if (ent->cache_info != 0) {
+ status = tls_scache_delete(ent->cache_info,
+ STR(cache_id)) ?
+ TLS_MGR_STAT_OK : TLS_MGR_STAT_ERR;
+ }
+ }
+ attr_print(client_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_INT(MAIL_ATTR_STATUS, status),
+ ATTR_TYPE_END);
+ }
+
+ /*
+ * RFC 5077 TLS session ticket keys
+ */
+ else if (STREQ(STR(request), TLS_MGR_REQ_TKTKEY)) {
+ if (attr_scan(client_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_DATA(TLS_MGR_ATTR_KEYNAME, buffer),
+ ATTR_TYPE_END) == 1) {
+ if (LEN(buffer) != 0 && LEN(buffer) != TLS_TICKET_NAMELEN) {
+ msg_warn("invalid session ticket key name length: %ld",
+ (long) LEN(buffer));
+ VSTRING_RESET(buffer);
+ } else if (*smtpd_cache.cache_timeout <= 0) {
+ status = TLS_MGR_STAT_ERR;
+ VSTRING_RESET(buffer);
+ } else {
+ status = tlsmgr_key(buffer, *smtpd_cache.cache_timeout);
+ }
+ }
+ attr_print(client_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_INT(MAIL_ATTR_STATUS, status),
+ SEND_ATTR_DATA(TLS_MGR_ATTR_KEYBUF,
+ LEN(buffer), STR(buffer)),
+ ATTR_TYPE_END);
+ }
+
+ /*
+ * Entropy request.
+ */
+ else if (STREQ(STR(request), TLS_MGR_REQ_SEED)) {
+ if (attr_scan(client_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_INT(TLS_MGR_ATTR_SIZE, &len),
+ ATTR_TYPE_END) == 1) {
+ VSTRING_RESET(buffer);
+ if (len <= 0 || len > 255) {
+ msg_warn("bogus seed length \"%d\" in \"%s\" request",
+ len, TLS_MGR_REQ_SEED);
+ } else {
+ VSTRING_SPACE(buffer, len);
+ RAND_bytes((unsigned char *) STR(buffer), len);
+ vstring_set_payload_size(buffer, len);
+ status = TLS_MGR_STAT_OK;
+ }
+ }
+ attr_print(client_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_INT(MAIL_ATTR_STATUS, status),
+ SEND_ATTR_DATA(TLS_MGR_ATTR_SEED,
+ LEN(buffer), STR(buffer)),
+ ATTR_TYPE_END);
+ }
+
+ /*
+ * Caching policy request.
+ */
+ else if (STREQ(STR(request), TLS_MGR_REQ_POLICY)) {
+ int cachable = 0;
+ int timeout = 0;
+
+ if (attr_scan(client_stream, ATTR_FLAG_STRICT,
+ RECV_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
+ ATTR_TYPE_END) == 1) {
+ for (ent = cache_table; ent->cache_label; ++ent)
+ if (strcmp(ent->cache_label, STR(cache_type)) == 0)
+ break;
+ if (ent->cache_label == 0) {
+ msg_warn("bogus cache type \"%s\" in \"%s\" request",
+ STR(cache_type), TLS_MGR_REQ_POLICY);
+ } else {
+ cachable = (ent->cache_info != 0) ? 1 : 0;
+ timeout = *ent->cache_timeout;
+ status = TLS_MGR_STAT_OK;
+ }
+ }
+ attr_print(client_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_INT(MAIL_ATTR_STATUS, status),
+ SEND_ATTR_INT(TLS_MGR_ATTR_CACHABLE, cachable),
+ SEND_ATTR_INT(TLS_MGR_ATTR_SESSTOUT, timeout),
+ ATTR_TYPE_END);
+ }
+
+ /*
+ * Master trigger. Normally, these triggers arrive only after some
+ * other process requested the tlsmgr's service. The purpose is to
+ * restart the tlsmgr after it aborted due to a fatal run-time error,
+ * so that it can continue its housekeeping even while nothing is
+ * using TLS.
+ *
+ * XXX Which begs the question, if TLS isn't used often, do we need a
+ * tlsmgr background process? It could terminate when the session
+ * caches are empty.
+ */
+ else if (STREQ(STR(request), wakeup)) {
+ if (msg_verbose)
+ msg_info("received master trigger");
+ multi_server_disconnect(client_stream);
+ return; /* NOT: vstream_fflush */
+ }
+ }
+
+ /*
+ * Protocol error.
+ */
+ else {
+ attr_print(client_stream, ATTR_FLAG_NONE,
+ SEND_ATTR_INT(MAIL_ATTR_STATUS, TLS_MGR_STAT_FAIL),
+ ATTR_TYPE_END);
+ }
+ vstream_fflush(client_stream);
+}
+
+/* tlsmgr_pre_init - pre-jail initialization */
+
+static void tlsmgr_pre_init(char *unused_name, char **unused_argv)
+{
+ char *path;
+ struct timeval tv;
+ TLSMGR_SCACHE *ent;
+ VSTRING *redirect;
+ HTABLE *dup_filter;
+ const char *dup_label;
+
+ /*
+ * If nothing else works then at least this will get us a few bits of
+ * entropy.
+ *
+ * XXX This is our first call into the OpenSSL library. We should find out
+ * if this can be moved to the post-jail initialization phase, without
+ * breaking compatibility with existing installations.
+ */
+ GETTIMEOFDAY(&tv);
+ tv.tv_sec ^= getpid();
+ RAND_seed(&tv, sizeof(struct timeval));
+
+ /*
+ * Open the external entropy source. We will not be able to open it again
+ * after we are sent to chroot jail, so we keep it open. Errors are not
+ * fatal. The exchange file (see below) is the only entropy source that
+ * really matters in the long run.
+ *
+ * Security note: we open the entropy source while privileged, but we don't
+ * access the source until after we release privileges. This way, none of
+ * the OpenSSL code gets to execute while we are privileged.
+ */
+ if (*var_tls_rand_source) {
+
+ /*
+ * Source is a random device.
+ */
+ if (!strncmp(var_tls_rand_source, DEV_PREF, DEV_PREF_LEN)) {
+ path = DEV_PATH(var_tls_rand_source);
+ rand_source_dev = tls_prng_dev_open(path, TLS_MGR_TIMEOUT);
+ if (rand_source_dev == 0)
+ msg_warn("cannot open entropy device %s: %m", path);
+ }
+
+ /*
+ * Source is an EGD compatible socket.
+ */
+ else if (!strncmp(var_tls_rand_source, EGD_PREF, EGD_PREF_LEN)) {
+ path = EGD_PATH(var_tls_rand_source);
+ rand_source_egd = tls_prng_egd_open(path, TLS_MGR_TIMEOUT);
+ if (rand_source_egd == 0)
+ msg_warn("cannot connect to EGD server %s: %m", path);
+ }
+
+ /*
+ * Source is regular file. We read this only once.
+ */
+ else {
+ rand_source_file =
+ tls_prng_file_open(var_tls_rand_source, TLS_MGR_TIMEOUT);
+ }
+ } else {
+ msg_warn("no entropy source specified with parameter %s",
+ VAR_TLS_RAND_SOURCE);
+ msg_warn("encryption keys etc. may be predictable");
+ }
+
+ /*
+ * Security: don't create root-owned files that contain untrusted data.
+ * And don't create Postfix-owned files in root-owned directories,
+ * either. We want a correct relationship between (file/directory)
+ * ownership and (file/directory) content.
+ */
+ SAVE_AND_SET_EUGID(var_owner_uid, var_owner_gid);
+ redirect = vstring_alloc(100);
+
+ /*
+ * Open the PRNG exchange file before going to jail, but don't use root
+ * privileges. Start the exchange file read/update pseudo thread after
+ * dropping privileges.
+ */
+ if (*var_tls_rand_exch_name) {
+ rand_exch =
+ tls_prng_exch_open(data_redirect_file(redirect,
+ var_tls_rand_exch_name));
+ if (rand_exch == 0)
+ msg_fatal("cannot open PRNG exchange file %s: %m",
+ var_tls_rand_exch_name);
+ }
+
+ /*
+ * Open the session cache files and discard old information before going
+ * to jail, but don't use root privilege. Start the cache maintenance
+ * pseudo threads after dropping privileges.
+ */
+ dup_filter = htable_create(sizeof(cache_table) / sizeof(cache_table[0]));
+ for (ent = cache_table; ent->cache_label; ++ent) {
+ /* Sanitize session timeout */
+ if (*ent->cache_timeout > 0) {
+ if (*ent->cache_timeout < TLS_SESSION_LIFEMIN)
+ *ent->cache_timeout = TLS_SESSION_LIFEMIN;
+ } else {
+ *ent->cache_timeout = 0;
+ }
+ /* External cache database disabled if timeout is non-positive */
+ if (*ent->cache_timeout > 0 && **ent->cache_db) {
+ if ((dup_label = htable_find(dup_filter, *ent->cache_db)) != 0)
+ msg_fatal("do not use the same TLS cache file %s for %s and %s",
+ *ent->cache_db, dup_label, ent->cache_label);
+ htable_enter(dup_filter, *ent->cache_db, ent->cache_label);
+ ent->cache_info =
+ tls_scache_open(data_redirect_map(redirect, *ent->cache_db),
+ ent->cache_label,
+ tls_log_mask(ent->log_param,
+ *ent->log_level) & TLS_LOG_CACHE,
+ *ent->cache_timeout);
+ }
+ }
+ htable_free(dup_filter, (void (*) (void *)) 0);
+
+ /*
+ * Clean up and restore privilege.
+ */
+ vstring_free(redirect);
+ RESTORE_SAVED_EUGID();
+}
+
+/* tlsmgr_post_init - post-jail initialization */
+
+static void tlsmgr_post_init(char *unused_name, char **unused_argv)
+{
+ TLSMGR_SCACHE *ent;
+
+#define NULL_EVENT (0)
+#define NULL_CONTEXT ((char *) 0)
+
+ /*
+ * This routine runs after the skeleton code has entered the chroot jail,
+ * but before any client requests are serviced. Prevent automatic process
+ * suicide after a limited number of client requests or after a limited
+ * amount of idle time.
+ */
+ var_use_limit = 0;
+ var_idle_limit = 0;
+
+ /*
+ * Start the internal PRNG re-seeding pseudo thread first.
+ */
+ if (*var_tls_rand_source) {
+ if (var_tls_reseed_period > INT_MAX / UCHAR_MAX)
+ var_tls_reseed_period = INT_MAX / UCHAR_MAX;
+ tlsmgr_reseed_event(NULL_EVENT, NULL_CONTEXT);
+ }
+
+ /*
+ * Start the exchange file read/update pseudo thread.
+ */
+ if (*var_tls_rand_exch_name) {
+ if (var_tls_prng_exch_period > INT_MAX / UCHAR_MAX)
+ var_tls_prng_exch_period = INT_MAX / UCHAR_MAX;
+ tlsmgr_prng_exch_event(NULL_EVENT, NULL_CONTEXT);
+ }
+
+ /*
+ * Start the cache maintenance pseudo threads last. Strictly speaking
+ * there is nothing to clean up after we truncate the database to zero
+ * length, but early cleanup makes verbose logging more informative (we
+ * get positive confirmation that the cleanup threads are running).
+ */
+ for (ent = cache_table; ent->cache_label; ++ent)
+ if (ent->cache_info)
+ tlsmgr_cache_run_event(NULL_EVENT, (void *) ent);
+}
+
+/* tlsmgr_before_exit - save PRNG state before exit */
+
+static void tlsmgr_before_exit(char *unused_service_name, char **unused_argv)
+{
+
+ /*
+ * Save state before we exit after "postfix reload".
+ */
+ if (rand_exch)
+ tls_prng_exch_update(rand_exch);
+}
+
+MAIL_VERSION_STAMP_DECLARE;
+
+/* main - the main program */
+
+int main(int argc, char **argv)
+{
+ static const CONFIG_STR_TABLE str_table[] = {
+ VAR_TLS_RAND_SOURCE, DEF_TLS_RAND_SOURCE, &var_tls_rand_source, 0, 0,
+ VAR_TLS_RAND_EXCH_NAME, DEF_TLS_RAND_EXCH_NAME, &var_tls_rand_exch_name, 0, 0,
+ VAR_SMTPD_TLS_SCACHE_DB, DEF_SMTPD_TLS_SCACHE_DB, &var_smtpd_tls_scache_db, 0, 0,
+ VAR_SMTP_TLS_SCACHE_DB, DEF_SMTP_TLS_SCACHE_DB, &var_smtp_tls_scache_db, 0, 0,
+ VAR_LMTP_TLS_SCACHE_DB, DEF_LMTP_TLS_SCACHE_DB, &var_lmtp_tls_scache_db, 0, 0,
+ VAR_SMTPD_TLS_LOGLEVEL, DEF_SMTPD_TLS_LOGLEVEL, &var_smtpd_tls_loglevel, 0, 0,
+ VAR_SMTP_TLS_LOGLEVEL, DEF_SMTP_TLS_LOGLEVEL, &var_smtp_tls_loglevel, 0, 0,
+ VAR_LMTP_TLS_LOGLEVEL, DEF_LMTP_TLS_LOGLEVEL, &var_lmtp_tls_loglevel, 0, 0,
+ 0,
+ };
+ static const CONFIG_TIME_TABLE time_table[] = {
+ VAR_TLS_RESEED_PERIOD, DEF_TLS_RESEED_PERIOD, &var_tls_reseed_period, 1, 0,
+ VAR_TLS_PRNG_UPD_PERIOD, DEF_TLS_PRNG_UPD_PERIOD, &var_tls_prng_exch_period, 1, 0,
+ VAR_SMTPD_TLS_SCACHTIME, DEF_SMTPD_TLS_SCACHTIME, &var_smtpd_tls_scache_timeout, 0, MAX_SMTPD_TLS_SCACHETIME,
+ VAR_SMTP_TLS_SCACHTIME, DEF_SMTP_TLS_SCACHTIME, &var_smtp_tls_scache_timeout, 0, MAX_SMTP_TLS_SCACHETIME,
+ VAR_LMTP_TLS_SCACHTIME, DEF_LMTP_TLS_SCACHTIME, &var_lmtp_tls_scache_timeout, 0, MAX_LMTP_TLS_SCACHETIME,
+ 0,
+ };
+ static const CONFIG_INT_TABLE int_table[] = {
+ VAR_TLS_RAND_BYTES, DEF_TLS_RAND_BYTES, &var_tls_rand_bytes, 1, 0,
+ 0,
+ };
+
+ /*
+ * Fingerprint executables and core dumps.
+ */
+ MAIL_VERSION_STAMP_ALLOCATE;
+
+ /*
+ * Use the multi service skeleton, and require that no-one else is
+ * monitoring our service port while this process runs.
+ */
+ multi_server_main(argc, argv, tlsmgr_service,
+ CA_MAIL_SERVER_TIME_TABLE(time_table),
+ CA_MAIL_SERVER_INT_TABLE(int_table),
+ CA_MAIL_SERVER_STR_TABLE(str_table),
+ CA_MAIL_SERVER_PRE_INIT(tlsmgr_pre_init),
+ CA_MAIL_SERVER_POST_INIT(tlsmgr_post_init),
+ CA_MAIL_SERVER_EXIT(tlsmgr_before_exit),
+ CA_MAIL_SERVER_LOOP(tlsmgr_loop),
+ CA_MAIL_SERVER_SOLITARY,
+ 0);
+}
+
+#else
+
+/* tlsmgr_service - respond to external trigger(s), non-TLS version */
+
+static void tlsmgr_service(VSTREAM *unused_stream, char *unused_service,
+ char **unused_argv)
+{
+ msg_info("TLS support is not compiled in -- exiting");
+}
+
+/* main - the main program, non-TLS version */
+
+int main(int argc, char **argv)
+{
+
+ /*
+ * 200411 We can't simply use msg_fatal() here, because the logging
+ * hasn't been initialized. The text would disappear because stderr is
+ * redirected to /dev/null.
+ *
+ * We invoke multi_server_main() to complete program initialization
+ * (including logging) and then invoke the tlsmgr_service() routine to
+ * log the message that says why this program will not run.
+ */
+ multi_server_main(argc, argv, tlsmgr_service,
+ 0);
+}
+
+#endif