From: Sergio Villar Senin <svillar@igalia.com>
Date: Wed, 29 Jul 2009 10:31:53 +0000 (+0200)
Subject: Fixes NB#122697, prevent DoS attacks when replying to emails with malformed "Reply... 
X-Git-Tag: 3.0.17-rc27~2
X-Git-Url: http://git.maemo.org/git/?p=modest;a=commitdiff_plain;h=4e20c90f5906916473d0720917f436f570ebb556;ds=sidebyside

Fixes NB#122697, prevent DoS attacks when replying to emails with malformed "Reply-To" or "From" headers
---

diff --git a/src/modest-text-utils.c b/src/modest-text-utils.c
index 7598f04..7032d07 100644
--- a/src/modest-text-utils.c
+++ b/src/modest-text-utils.c
@@ -2008,3 +2008,19 @@ modest_text_utils_remove_duplicate_addresses_list (GSList *address_list)
 
 	return new_list;
 }
+
+gchar *
+modest_text_utils_get_secure_header (gchar *value,
+				     const gchar *header)
+{
+	gchar *new_value = value;
+	gchar *needle = g_strrstr (value, header);
+
+	if (needle) {
+		gchar *tmp = value;
+		new_value = g_strdup (needle + strlen (header));
+		g_free (tmp);
+	}
+
+	return new_value;
+}
diff --git a/src/modest-text-utils.h b/src/modest-text-utils.h
index 3608935..ecd1c93 100644
--- a/src/modest-text-utils.h
+++ b/src/modest-text-utils.h
@@ -515,4 +515,17 @@ gchar *modest_text_utils_simplify_recipients (const gchar *recipient);
  */
 GSList *modest_text_utils_remove_duplicate_addresses_list (GSList *address_list);
 
+/**
+ * modest_text_utils_get_secure_header:
+ * @value: the value of a mail header
+ * @header: the header that we're evaluating
+ *
+ * This function returns the secure value for a header. Basically it
+ * avoids DoS attacks caused by specially malformed headers like for
+ * example. From:From:From...From: some@mail.com
+ *
+ * Returns: returns the secured header
+ **/
+gchar * modest_text_utils_get_secure_header (gchar *value, const gchar *header);
+
 #endif /* __MODEST_TEXT_UTILS_H__ */
diff --git a/src/modest-tny-msg.c b/src/modest-tny-msg.c
index 8e4c86f..82d257f 100644
--- a/src/modest-tny-msg.c
+++ b/src/modest-tny-msg.c
@@ -961,6 +961,8 @@ static gchar*
 get_new_to (TnyMsg *msg, TnyHeader *header, const gchar* from,
 	    ModestTnyMsgReplyMode reply_mode)
 {
+	const gchar *reply_header = "Reply-To:";
+	const gchar *from_header = "From:";
 	gchar* old_reply_to;
 	gchar* old_from;
 	gchar* new_to;
@@ -981,13 +983,21 @@ get_new_to (TnyMsg *msg, TnyHeader *header, const gchar* from,
 	old_reply_to = modest_tny_mime_part_get_header_value (TNY_MIME_PART(msg), 
 							      "Reply-To"); 
 	old_from     = tny_header_dup_from (header);
-	
+
 	if (!old_from && !old_reply_to) {
 		g_debug ("%s: failed to get either Reply-To: or From: from header",
 			   __FUNCTION__);
 		return NULL;
 	}
-	
+
+	/* Prevent DoS attacks caused by malformed emails */
+	if (old_from)
+		old_from = modest_text_utils_get_secure_header (old_from,
+								from_header);
+	if (old_reply_to)
+		old_reply_to = modest_text_utils_get_secure_header (old_reply_to,
+								    reply_header);
+
 	/* for mailing lists, use both Reply-To and From if we did a
 	 * 'Reply All:'
 	 * */