From 5bc72de8fe74424fbcd9f17aba92185473db00ca Mon Sep 17 00:00:00 2001
From: Simon Schubert <2@0x2c.org>
Date: Wed, 16 Nov 2011 12:38:49 +0100
Subject: [PATCH] implement masquerading using the MASQUERADE config option

---
 conf.c   | 18 +++++++++++++++++-
 dma.8    | 30 ++++++++++++++++++++++++++++++
 dma.c    | 11 ++++++++++-
 dma.conf | 10 ++++++++++
 dma.h    |  2 ++
 5 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/conf.c b/conf.c
index 060e0cd..29b6e1b 100644
--- a/conf.c
+++ b/conf.c
@@ -203,7 +203,23 @@ parse_conf(const char *config_path)
 			config.certfile = data;
 		else if (strcmp(word, "MAILNAME") == 0 && data != NULL)
 			config.mailname = data;
-		else if (strcmp(word, "STARTTLS") == 0 && data == NULL)
+		else if (strcmp(word, "MASQUERADE") == 0 && data != NULL) {
+			char *user = NULL, *host = NULL;
+			if (strrchr(data, '@')) {
+				host = strrchr(data, '@');
+				host = 0;
+				host++;
+				user = data;
+			} else {
+				host = data;
+			}
+ 			if (host && *host == 0)
+				host = NULL;
+                        if (user && *user == 0)
+                                user = NULL;
+			config.masquerade_host = host;
+			config.masquerade_user = user;
+		} else if (strcmp(word, "STARTTLS") == 0 && data == NULL)
 			config.features |= STARTTLS;
 		else if (strcmp(word, "OPPORTUNISTIC_TLS") == 0 && data == NULL)
 			config.features |= TLS_OPP;
diff --git a/dma.8 b/dma.8
index 18b2c8c..d34b3d6 100644
--- a/dma.8
+++ b/dma.8
@@ -262,6 +262,36 @@ If
 .Sq MAILNAME
 is an absolute path to a file, the first line of this file will be used
 as the hostname.
+.It Ic MASQUERADE Xo
+(string, default=empty)
+.Xc
+Masquerade the envelope from addresses with this address/hostname.
+Use this setting if mails are not accepted by destination mail servers
+because your sender domain is invalid.
+This setting is overridden by the
+.Fl f
+flag and the
+.Ev EMAIL
+environment variable.
+.Pp
+If
+.Sq MASQUERADE
+does not contain a
+.Li @
+sign, the string is interpreted as a host name.
+For example, setting
+.Sq MASQUERADE
+to
+.Ql john@
+on host
+.Ql hamlet
+will send all mails as
+.Ql john@hamlet ;
+setting it to
+.Ql percolator
+will send all mails as
+.Ql Sm off Va username @percolator .
+.Sm on
 .El
 .Ss Environment variables
 The behavior of
diff --git a/dma.c b/dma.c
index 5a287fa..205e2bf 100644
--- a/dma.c
+++ b/dma.c
@@ -80,6 +80,8 @@ struct config config = {
 	.certfile	= NULL,
 	.features	= 0,
 	.mailname	= NULL,
+	.masquerade_host = NULL,
+	.masquerade_user = NULL,
 };
 
 
@@ -103,7 +105,14 @@ set_from(struct queue *queue, const char *osender)
 		if (sender == NULL)
 			return (NULL);
 	} else {
-		if (asprintf(&sender, "%s@%s", username, hostname()) <= 0)
+		const char *from_user = username;
+		const char *from_host = hostname();
+
+		if (config.masquerade_user)
+			from_user = config.masquerade_user;
+		if (config.masquerade_host)
+			from_host = config.masquerade_host;
+		if (asprintf(&sender, "%s@%s", from_user, from_host) <= 0)
 			return (NULL);
 	}
 
diff --git a/dma.conf b/dma.conf
index d9ae76b..56fa104 100644
--- a/dma.conf
+++ b/dma.conf
@@ -51,3 +51,13 @@
 # If MAILNAME is an absolute path to a file, the first line of this file
 # will be used as the hostname.
 #MAILNAME mail.example.net
+
+# Masquerade envelope from addresses with this address/hostname.
+# Use this if mails are not accepted by destination mail servers because
+# your sender domain is invalid.
+# By default, MASQUERADE is not set.
+# Format: MASQUERADE [user@][host]
+# Examples:
+# MASQUERADE john@  on host "hamlet" will send all mails as john@hamlet
+# MASQUERADE percolator  will send mails as $username@percolator, e.g. fish@percolator
+# MASQUERADE herb@ert  will send all mails as herb@ert
diff --git a/dma.h b/dma.h
index 03139dc..029f41c 100644
--- a/dma.h
+++ b/dma.h
@@ -121,6 +121,8 @@ struct config {
 	const char *certfile;
 	int features;
 	const char *mailname;
+	const char *masquerade_host;
+	const char *masquerade_user;
 
 	/* XXX does not belong into config */
 	SSL *ssl;
-- 
2.39.2