sync

7 files changed, 128 insertions, 12 deletions

diff --git a/smtpd/config.c b/smtpd/config.c
index 8b8b8570..cc53272a 100644
--- a/smtpd/config.c
+++ b/smtpd/config.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: config.c,v 1.49 2018/12/28 14:21:02 eric Exp $	*/
+/*	$OpenBSD: config.c,v 1.50 2019/09/20 17:46:05 gilles Exp $	*/
 
 /*
  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
@@ -60,6 +60,7 @@ config_default(void)
 	conf->sc_maxsize = DEFAULT_MAX_BODY_SIZE;
 	conf->sc_subaddressing_delim = SUBADDRESSING_DELIMITER;
 	conf->sc_ttl = SMTPD_QUEUE_EXPIRY;
+	conf->sc_srs_ttl = SMTPD_QUEUE_EXPIRY / 86400;
 
 	conf->sc_mta_max_deferred = 100;
 	conf->sc_scheduler_max_inflight = 5000;
diff --git a/smtpd/lka_session.c b/smtpd/lka_session.c
index ed17adcb..ed1fd36f 100644
--- a/smtpd/lka_session.c
+++ b/smtpd/lka_session.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lka_session.c,v 1.92 2018/12/28 11:40:29 eric Exp $	*/
+/*	$OpenBSD: lka_session.c,v 1.93 2019/09/20 17:46:05 gilles Exp $	*/
 
 /*
  * Copyright (c) 2011 Gilles Chehade <gilles@poolp.org>
@@ -267,7 +267,8 @@ lka_expand(struct lka_session *lks, struct rule *rule, struct expandnode *xn)
 	int			r;
 	union lookup		lk;
 	char		       *tag;
-	
+	const char	       *srs_decoded;
+
 	if (xn->depth >= EXPAND_DEPTH) {
 		log_trace(TRACE_EXPAND, "expand: lka_expand: node too deep.");
 		lks->error = LKA_PERMFAIL;
@@ -287,12 +288,32 @@ lka_expand(struct lka_session *lks, struct rule *rule, struct expandnode *xn)
 		    "[depth=%d]",
 		    xn->u.mailaddr.user, xn->u.mailaddr.domain, xn->depth);
 
-		/* Pass the node through the ruleset */
+
 		ep = lks->envelope;
 		ep.dest = xn->u.mailaddr;
 		if (xn->parent) /* nodes with parent are forward addresses */
 			ep.flags |= EF_INTERNAL;
 
+		/* handle SRS */
+		if (env->sc_srs_key != NULL &&
+		    ep.sender.user[0] == '\0' &&
+		    (strncasecmp(ep.rcpt.user, "SRS0=", 5) == 0 ||
+			strncasecmp(ep.rcpt.user, "SRS1=", 5) == 0)) {
+			srs_decoded = srs_decode(mailaddr_to_text(&ep.rcpt));
+			if (srs_decoded &&
+			    text_to_mailaddr(&ep.rcpt, srs_decoded)) {
+				/* flag envelope internal and override rcpt */
+				ep.flags |= EF_INTERNAL;
+				xn->u.mailaddr = ep.rcpt;
+				lks->envelope = ep;
+			}
+			else {
+				log_warn("SRS failed to decode: %s",
+				    mailaddr_to_text(&ep.rcpt));
+			}
+		}
+
+		/* Pass the node through the ruleset */
 		rule = ruleset_match(&ep);
 		if (rule == NULL || rule->reject) {
 			lks->error = (errno == EAGAIN) ?
diff --git a/smtpd/mta.c b/smtpd/mta.c
index 926b089a..6c817d00 100644
--- a/smtpd/mta.c
+++ b/smtpd/mta.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mta.c,v 1.231 2019/09/18 11:26:30 eric Exp $	*/
+/*	$OpenBSD: mta.c,v 1.232 2019/09/20 17:46:05 gilles Exp $	*/
 
 /*
  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
@@ -1735,6 +1735,7 @@ mta_relay(struct envelope *e, struct relayhost *relayh)
 	key.sourcetable = dispatcher->u.remote.source;
 	key.helotable = dispatcher->u.remote.helo_source;
 	key.heloname = dispatcher->u.remote.helo;
+	key.srs = dispatcher->u.remote.srs;
 
 	if (relayh->hostname[0]) {
 		key.domain = mta_domain(relayh->hostname, 1);
@@ -1782,6 +1783,7 @@ mta_relay(struct envelope *e, struct relayhost *relayh)
 			r->helotable = xstrdup(key.helotable);
 		if (key.heloname)
 			r->heloname = xstrdup(key.heloname);
+		r->srs = key.srs;
 		SPLAY_INSERT(mta_relay_tree, &relays, r);
 		stat_increment("mta.relay", 1);
 	} else {
@@ -2089,6 +2091,11 @@ mta_relay_cmp(const struct mta_relay *a, const struct mta_relay *b)
 	if (a->backupname && ((r = strcmp(a->backupname, b->backupname))))
 		return (r);
 
+	if (a->srs < b->srs)
+		return (-1);
+	if (a->srs > b->srs)
+		return (1);
+
 	return (0);
 }
 
diff --git a/smtpd/mta_session.c b/smtpd/mta_session.c
index f5366623..72969e0a 100644
--- a/smtpd/mta_session.c
+++ b/smtpd/mta_session.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mta_session.c,v 1.121 2019/09/18 11:26:30 eric Exp $	*/
+/*	$OpenBSD: mta_session.c,v 1.122 2019/09/20 17:46:05 gilles Exp $	*/
 
 /*
  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
@@ -529,8 +529,9 @@ mta_enter_state(struct mta_session *s, int newstate)
 	char			 ibuf[LINE_MAX];
 	char			 obuf[LINE_MAX];
 	int			 offset;
+	const char     		*srs_sender;
 
-    again:
+again:
 	oldstate = s->state;
 
 	log_trace(TRACE_MTA, "mta: %p: %s -> %s", s,
@@ -728,6 +729,25 @@ mta_enter_state(struct mta_session *s, int newstate)
 		s->hangon = 0;
 		s->msgtried++;
 		envid_sz = strlen(e->dsn_envid);
+
+		/* SRS-encode if requested for the relay action, AND we're not
+		 * bouncing, AND we have an RCPT which means we are forwarded,
+		 * AND the RCPT has a '@' just for sanity check (will always).
+		 */
+		if (env->sc_srs_key != NULL &&
+		    s->relay->srs &&
+		    strchr(s->task->sender, '@') &&
+		    e->rcpt &&
+		    strchr(e->rcpt, '@')) {
+			/* encode and replace task sender with new SRS-sender */
+			srs_sender = srs_encode(s->task->sender,
+			    strchr(e->rcpt, '@') + 1);
+			if (srs_sender) {
+				free(s->task->sender);
+				s->task->sender = xstrdup(srs_sender);
+			}
+		}
+
 		if (s->ext & MTA_EXT_DSN) {
 			mta_send(s, "MAIL FROM:<%s>%s%s%s%s",
 			    s->task->sender,
diff --git a/smtpd/parse.y b/smtpd/parse.y
index e52077aa..4801d14f 100644
--- a/smtpd/parse.y
+++ b/smtpd/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.261 2019/09/06 08:23:56 martijn Exp $	*/
+/*	$OpenBSD: parse.y,v 1.262 2019/09/20 17:46:05 gilles Exp $	*/
 
 /*
  * Copyright (c) 2008 Gilles Chehade <gilles@poolp.org>
@@ -191,7 +191,7 @@ typedef struct {
 %token	PHASE PKI PORT PROC PROC_EXEC PROXY_V2
 %token	QUEUE QUIT
 %token	RCPT_TO RDNS RECIPIENT RECEIVEDAUTH REGEX RELAY REJECT REPORT REWRITE RSET
-%token	SCHEDULER SENDER SENDERS SMTP SMTP_IN SMTP_OUT SMTPS SOCKET SRC SUB_ADDR_DELIM
+%token	SCHEDULER SENDER SENDERS SMTP SMTP_IN SMTP_OUT SMTPS SOCKET SRC SRS SUB_ADDR_DELIM
 %token	TABLE TAG TAGGED TLS TLS_REQUIRE TTL
 %token	USER USERBASE
 %token	VERIFY VIRTUAL
@@ -217,6 +217,7 @@ grammar		: /* empty */
 		| grammar queue '\n'
 		| grammar scheduler '\n'
 		| grammar smtp '\n'
+		| grammar srs '\n'
 		| grammar listen '\n'
 		| grammar table '\n'
 		| grammar dispatcher '\n'
@@ -537,6 +538,31 @@ SMTP LIMIT limits_smtp
 }
 ;
 
+srs:
+SRS KEY STRING {
+	conf->sc_srs_key = $3;
+}
+SRS KEY BACKUP STRING {
+	conf->sc_srs_key_backup = $3;
+}
+| SRS TTL STRING {
+	conf->sc_srs_ttl = delaytonum($3);
+	if (conf->sc_srs_ttl == -1) {
+		yyerror("ttl delay \"%s\" is invalid", $3);
+		free($3);
+		YYERROR;
+	}
+
+	conf->sc_srs_ttl /= 86400;
+	if (conf->sc_srs_ttl == 0) {
+		yyerror("ttl delay \"%s\" is too short", $3);
+		free($3);
+		YYERROR;
+	}
+	free($3);
+}
+;
+
 
 dispatcher_local_option:
 USER STRING {
@@ -830,6 +856,18 @@ HELO STRING {
 
 	dispatcher->u.remote.auth = strdup(t->t_name);
 }
+| SRS {
+	if (conf->sc_srs_key == NULL) {
+		yyerror("an srs key is required for srs to be specified in an action");
+		YYERROR;
+	}
+	if (dispatcher->u.remote.srs == 1) {
+		yyerror("srs already specified for this dispatcher");
+		YYERROR;
+	}
+
+	dispatcher->u.remote.srs = 1;
+}
 ;
 
 dispatcher_remote_options:
@@ -2377,6 +2415,7 @@ lookup(char *s)
 		{ "smtps",		SMTPS },
 		{ "socket",		SOCKET },
 		{ "src",		SRC },
+		{ "srs",		SRS },
 		{ "sub-addr-delim",	SUB_ADDR_DELIM },
 		{ "table",		TABLE },
 		{ "tag",		TAG },
diff --git a/smtpd/smtpd.conf.5 b/smtpd/smtpd.conf.5
index 4de04c95..1da4189c 100644
--- a/smtpd/smtpd.conf.5
+++ b/smtpd/smtpd.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: smtpd.conf.5,v 1.224 2019/09/06 08:23:56 martijn Exp $
+.\"	$OpenBSD: smtpd.conf.5,v 1.225 2019/09/20 17:46:05 gilles Exp $
 .\"
 .\" Copyright (c) 2008 Janne Johansson <jj@openbsd.org>
 .\" Copyright (c) 2009 Jacek Masiulaniec <jacekm@dobremiasto.net>
@@ -17,7 +17,7 @@
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
 .\"
-.Dd $Mdocdate: September 6 2019 $
+.Dd $Mdocdate: September 20 2019 $
 .Dt SMTPD.CONF 5
 .Os
 .Sh NAME
@@ -270,6 +270,9 @@ and
 .Dq smtps
 protocols for authentication.
 Server certificates for those protocols are verified by default.
+.It Cm srs
+When relaying a mail resulting from a forward,
+use the Sender Rewriting Scheme to rewrite sender address.
 .It Cm tls Op Cm no-verify
 Require TLS to be used when relaying, using mandatory STARTTLS by default.
 When used with a smarthost, the protocol must not be
@@ -842,6 +845,19 @@ When resolving the local part of a local email address, ignore the ASCII
 and all characters following it.
 The default is
 .Ql + .
+.It Ic srs Cm key Ar secret
+Set the secret key to use for SRS,
+the Sender Rewriting Scheme.
+.It Ic srs Cm key backup Ar secret
+Set a backup secret key to use as a fallback for SRS.
+This can be used to implementation SRS key rotation.
+.It Ic srs Cm ttl Ar delay
+Set the time-to-live delay for SRS envelopes.
+After this delay,
+a bounce reply to the SRS address will be discarded to limit risks of forged addresses.
+The default is four days
+.Pq 4d .
+The delay
 .It Ic table Ar name Oo Ar type : Oc Ns Ar pathname
 Tables provide additional configuration information for
 .Xr smtpd 8
diff --git a/smtpd/smtpd.h b/smtpd/smtpd.h
index e5a968e9..7ba6a472 100644
--- a/smtpd/smtpd.h
+++ b/smtpd/smtpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: smtpd.h,v 1.638 2019/09/19 07:35:36 gilles Exp $	*/
+/*	$OpenBSD: smtpd.h,v 1.639 2019/09/20 17:46:05 gilles Exp $	*/
 
 /*
  * Copyright (c) 2008 Gilles Chehade <gilles@poolp.org>
@@ -618,6 +618,10 @@ struct smtpd {
 	char				       *sc_tls_ciphers;
 
 	char				       *sc_subaddressing_delim;
+
+	char				       *sc_srs_key;
+	char				       *sc_srs_key_backup;
+	int				        sc_srs_ttl;
 };
 
 #define	TRACE_DEBUG	0x0001
@@ -804,6 +808,7 @@ struct mta_relay {
 	char			*helotable;
 	char			*heloname;
 	char			*secret;
+	int			 srs;
 
 	int			 state;
 	size_t			 ntask;
@@ -1162,6 +1167,8 @@ struct dispatcher_remote {
 
 	int	 backup;
 	char	*backupmx;
+
+	int	 srs;
 };
 
 struct dispatcher_bounce {
@@ -1587,6 +1594,11 @@ void log_imsg(int, int, struct imsg *);
 int fork_proc_backend(const char *, const char *, const char *);
 
 
+/* srs.c */
+const char *srs_encode(const char *, const char *);
+const char *srs_decode(const char *);
+
+
 /* ssl_smtpd.c */
 void   *ssl_mta_init(void *, char *, off_t, const char *);
 void   *ssl_smtp_init(void *, int);