Fix the Sender problem.

svn path=/trunk/; revision=3307

3 files changed, 23 insertions, 4 deletions

diff --git a/NEWS b/NEWS
index 1559a766..3799c937 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,7 @@
 * GCC warning cleanups from ahaas@neosoft.com.
 * Plug another hole that was letting zombies through.
 * SA_RESDTART portability fix for SunOS.
+* Ignore Sender and Resent-Sender headers unless they contain @.
 
 fetchmail-5.8.2 (Tue May  8 17:07:53 EDT 2001), 20481 lines:
 
diff --git a/driver.c b/driver.c
index 4038b484..11338f77 100644
--- a/driver.c
+++ b/driver.c
@@ -760,9 +760,27 @@ static int readheaders(int sock,
 	    resent_from_offs = (line - msgblk.headers);
 	else if (!strncasecmp("Apparently-From:", line, 16))
 	    app_from_offs = (line - msgblk.headers);
-	else if (!strncasecmp("Sender:", line, 7))
+	/*
+	 * Netscape 4.7 puts "Sender: zap" in mail headers.  Perverse...
+	 *
+	 * But a literal reading of RFC822 sec. 4.4.2 supports the idea
+	 * that Sender: *doesn't* have to be a working email address.
+	 *
+	 * The definition of the Sender header in RFC822 says, in
+	 * part, "The Sender mailbox specification includes a word
+	 * sequence which must correspond to a specific agent (i.e., a
+	 * human user or a computer program) rather than a standard
+	 * address."  That implies that the contents of the Sender
+	 * field don't need to be a legal email address at all So
+	 * ignore any Sender or Resent-Semnder lines unless they
+	 * contain @.
+	 *
+	 * (RFC2822 says the condents of Sender must be a valid mailbox
+	 * address, which is also what RFC822 4.4.4 implies.)
+	 */
+	else if (!strncasecmp("Sender:", line, 7) && strchr(line, '@'))
 	    sender_offs = (line - msgblk.headers);
-	else if (!strncasecmp("Resent-Sender:", line, 14))
+	else if (!strncasecmp("Resent-Sender:", line, 14) && strchr(line, '@'))
 	    resent_sender_offs = (line - msgblk.headers);
 
 #ifdef __UNUSED__
diff --git a/fetchmail.man b/fetchmail.man
index ad6ab70f..cc7e46a2 100644
--- a/fetchmail.man
+++ b/fetchmail.man
@@ -1633,8 +1633,8 @@ When trying to determine the originating address of a message,
 fetchmail looks through headers in the following order: 
 
         Return-Path:
-        Resent-Sender:
-        Sender:
+        Resent-Sender: (ignored if it doesn't contain an @)
+        Sender: (ignored if it doesn't contain an @)
         Resent-From:
         From:
         Reply-To: