From 0e9b2a152729bfd457e656a9258a06cbfdac1bae Mon Sep 17 00:00:00 2001
From: Akira TAGOH <akira@tagoh.org>
Date: Mon, 14 Nov 2016 20:14:35 +0900
Subject: Fix FcCacheOffsetsValid()

Validation fails when the FcValueList contains more than font->num.
this logic was wrong because font->num contains a number of the elements
in FcPatternElt but FcValue in FcValueList.

This corrects 7a4a5bd7.

Patch from Tobias Stoeckmann

diff --git a/src/fccache.c b/src/fccache.c
index 02ec301..6f3c68a 100644
--- a/src/fccache.c
+++ b/src/fccache.c
@@ -640,6 +640,7 @@ FcCacheOffsetsValid (FcCache *cache)
             FcPattern		*font = FcFontSetFont (fs, i);
             FcPatternElt	*e;
             FcValueListPtr	 l;
+	    char                *last_offset;
 
             if ((char *) font < base ||
                 (char *) font > end - sizeof (FcFontSet) ||
@@ -653,11 +654,17 @@ FcCacheOffsetsValid (FcCache *cache)
             if (e->values != 0 && !FcIsEncodedOffset(e->values))
                 return FcFalse;
 
-            for (j = font->num, l = FcPatternEltValues(e); j >= 0 && l; j--, l = FcValueListNext(l))
-                if (l->next != NULL && !FcIsEncodedOffset(l->next))
-                    break;
-            if (j < 0)
-                return FcFalse;
+	    for (j = 0; j < font->num; j++)
+	    {
+		last_offset = (char *) font + font->elts_offset;
+		for (l = FcPatternEltValues(&e[j]); l; l = FcValueListNext(l))
+		{
+		    if ((char *) l < last_offset || (char *) l > end - sizeof (*l) ||
+			(l->next != NULL && !FcIsEncodedOffset(l->next)))
+			return FcFalse;
+		    last_offset = (char *) l + 1;
+		}
+	    }
         }
     }
 
-- 
cgit v0.10.2