From: Emden Gansner <emdenrg@google.com>
Date: Thu, 22 Dec 2016 20:58:24 +0000 (-0500)
Subject: Don't use aptr->u.asym unless it has been set. This can cause a crash if aptr->u... 
X-Git-Tag: 2.40.1~1
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9d4335bd4fd803497183f4a41c4102d34d4d4ffc;p=graphviz

Don't use aptr->u.asym unless it has been set. This can cause a crash if aptr->u.asym->name is referenced.
---

diff --git a/lib/cgraph/grammar.y b/lib/cgraph/grammar.y
index 6d83a9f91..90aa27387 100644
--- a/lib/cgraph/grammar.y
+++ b/lib/cgraph/grammar.y
@@ -352,6 +352,8 @@ static void attrstmt(int tkind, char *macroname)
 	}
 	bindattrs(kind);	/* set up defaults for new attributes */
 	for (aptr = S->attrlist.first; aptr; aptr = aptr->next) {
+		/* If the tag is still T_atom, aptr->u.asym has not been set */
+		if (aptr->tag == T_atom) continue;
 		if (!(aptr->u.asym->fixed) || (S->g != G))
 			sym = agattr(S->g,kind,aptr->u.asym->name,aptr->str);
 		else