From 625ac28c61b0a5e6a252db00d72fbac6d88718fd Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Tue, 2 Jul 2013 21:19:32 +0100
Subject: [PATCH] Fix crash with empty DHCP string options.

---
 src/rfc2131.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/rfc2131.c b/src/rfc2131.c
index 499f5c4..e7fa75f 100644
--- a/src/rfc2131.c
+++ b/src/rfc2131.c
@@ -1833,7 +1833,8 @@ static int do_opt(struct dhcp_opt *opt, unsigned char *p, struct dhcp_context *c
 	    }
 	}
       else
-	memcpy(p, opt->val, len);
+	/* empty string may be extended to "\0" by null_term */
+	memcpy(p, opt->val ? opt->val : (unsigned char *)"", len);
     }  
   return len;
 }
-- 
1.7.2.5