--- source3/passdb/passdb.c	2009-10-29 03:47:16.000000000 -0400
+++ source3/passdb/passdb.c	2010-02-10 00:25:44.000000000 -0500
@@ -121,6 +121,18 @@
 	return user;
 }

+static int count_commas(const char *str)
+{
+	int num_commas = 0;
+	const char *comma = str;
+	while ((comma = strchr(comma, ',')) != NULL) {
+		comma += 1;
+		num_commas += 1;
+	}
+
+	return num_commas;
+}
+
 /*********************************************************************
  Initialize a struct samu from a struct passwd including the user
  and group SIDs.  The *user structure is filled out with the Unix
@@ -131,6 +143,7 @@
 {
 	const char *guest_account = lp_guestaccount();
 	const char *domain = global_myname();
+	char *fullname;
 	uint32 urid;

 	if ( !pwd ) {
@@ -140,7 +153,29 @@
 	/* Basic properties based upon the Unix account information */

 	pdb_set_username(user, pwd->pw_name, PDB_SET);
-	pdb_set_fullname(user, pwd->pw_gecos, PDB_SET);
+
+	fullname = NULL;
+
+	if (count_commas(pwd->pw_gecos) == 3) {
+		/*
+		 * Heuristic: This seems to be a gecos field that has been
+		 * edited by chfn(1). Only use the part before the first
+		 * comma. Fixes bug 5198.
+		 */
+		fullname = talloc_strndup(
+			talloc_tos(), pwd->pw_gecos,
+			strchr(pwd->pw_gecos, ',') - pwd->pw_gecos);
+
+
+	}
+
+	if (fullname != NULL) {
+		pdb_set_fullname(user, fullname, PDB_SET);
+	} else {
+		pdb_set_fullname(user, pwd->pw_gecos, PDB_SET);
+	}
+	TALLOC_FREE(fullname);
+
 	pdb_set_domain (user, get_global_sam_name(), PDB_DEFAULT);
 #if 0
 	/* This can lead to a primary group of S-1-22-2-XX which