Bump cache version up from 2 to 3 and fix FcLangSet caching/crash

Protect cache against future expansions of FcLangSet (adding new
orth files).  Previously, doing so could change the size of
that struct.  Indeed, that happened between 2.6.0 and 2.7.3, causing
crashes.  Unfortunately, sizeof(FcLangSet) was not checked in fcarch.c.

This changes FcLangSet code to be able to cope with struct size changes.
And change cache format, hence bumping from 2 to 3.

3 files changed, 54 insertions, 17 deletions

diff --git a/fontconfig/fontconfig.h b/fontconfig/fontconfig.h
index a0f8de5..7b36056 100644
--- a/fontconfig/fontconfig.h
+++ b/fontconfig/fontconfig.h
@@ -67,7 +67,7 @@ typedef int		FcBool;
  * it means multiple copies of the font information.
  */
 
-#define FC_CACHE_VERSION    "2"
+#define FC_CACHE_VERSION    "3"
 
 #define FcTrue		1
 #define FcFalse		0
diff --git a/src/fcint.h b/src/fcint.h
index 81cde21..4371158 100644
--- a/src/fcint.h
+++ b/src/fcint.h
@@ -432,7 +432,7 @@ typedef struct _FcCaseFold {
 
 #define FC_CACHE_MAGIC_MMAP	    0xFC02FC04
 #define FC_CACHE_MAGIC_ALLOC	    0xFC02FC05
-#define FC_CACHE_CONTENT_VERSION    2
+#define FC_CACHE_CONTENT_VERSION    3 /* also check FC_CACHE_VERSION */
 
 struct _FcAtomic {
     FcChar8	*file;		/* original file name */
diff --git a/src/fclang.c b/src/fclang.c
index ab7ae53..0f2f963 100644
--- a/src/fclang.c
+++ b/src/fclang.c
@@ -38,12 +38,38 @@ typedef struct {
 #include "../fc-lang/fclang.h"
 
 struct _FcLangSet {
-    FcChar32	map[NUM_LANG_SET_MAP];
     FcStrSet	*extra;
+    int         map_size;
+    FcChar32	map[NUM_LANG_SET_MAP];
 };
 
-#define FcLangSetBitSet(ls, id)	((ls)->map[(fcLangCharSetIndices[id])>>5] |= ((FcChar32) 1 << ((fcLangCharSetIndices[id]) & 0x1f)))
-#define FcLangSetBitGet(ls, id) (((ls)->map[(fcLangCharSetIndices[id])>>5] >> ((fcLangCharSetIndices[id]) & 0x1f)) & 1)
+static void
+FcLangSetBitSet (FcLangSet    *ls,
+		 unsigned int  id)
+{
+  int bucket;
+
+  id = fcLangCharSetIndices[id];
+  bucket = id >> 5;
+  if (bucket >= ls->map_size)
+    return; /* shouldn't happen really */
+
+  ls->map[bucket] |= ((FcChar32) 1 << (id & 0x1f));
+}
+
+static FcBool
+FcLangSetBitGet (const FcLangSet *ls,
+		 unsigned int     id)
+{
+  int bucket;
+
+  id = fcLangCharSetIndices[id];
+  bucket = id >> 5;
+  if (bucket >= ls->map_size)
+    return FcFalse;
+
+  return ((ls->map[bucket] >> (id & 0x1f)) & 1) ? FcTrue : FcFalse;
+}
 
 FcLangSet *
 FcFreeTypeLangSet (const FcCharSet  *charset, 
@@ -210,6 +236,7 @@ FcLangGetCharSet (const FcChar8 *lang)
 	case FcLangDifferentTerritory:
 	    if (country == -1)
 		country = i;
+	case FcLangDifferentLang:
 	default:
 	    break;
 	}
@@ -245,6 +272,7 @@ FcLangSetCreate (void)
 	return 0;
     FcMemAlloc (FC_MEM_LANGSET, sizeof (FcLangSet));
     memset (ls->map, '\0', sizeof (ls->map));
+    ls->map_size = NUM_LANG_SET_MAP;
     ls->extra = 0;
     return ls;
 }
@@ -266,7 +294,8 @@ FcLangSetCopy (const FcLangSet *ls)
     new = FcLangSetCreate ();
     if (!new)
 	goto bail0;
-    memcpy (new->map, ls->map, sizeof (new->map));
+    memset (new->map, '\0', sizeof (new->map));
+    memcpy (new->map, ls->map, FC_MIN (sizeof (new->map), ls->map_size * sizeof (ls->map[0])));
     if (ls->extra)
     {
 	FcStrList	*list;
@@ -442,15 +471,17 @@ FcLangSetCompareStrSet (const FcLangSet *ls, FcStrSet *set)
 FcLangResult
 FcLangSetCompare (const FcLangSet *lsa, const FcLangSet *lsb)
 {
-    int		    i, j;
+    int		    i, j, count;
     FcLangResult    best, r;
 
-    for (i = 0; i < NUM_LANG_SET_MAP; i++)
+    count = FC_MIN (lsa->map_size, lsb->map_size);
+    count = FC_MIN (NUM_LANG_SET_MAP, count);
+    for (i = 0; i < count; i++)
 	if (lsa->map[i] & lsb->map[i])
 	    return FcLangEqual;
     best = FcLangDifferentLang;
     for (j = 0; j < NUM_COUNTRY_SET; j++)
-	for (i = 0; i < NUM_LANG_SET_MAP; i++)
+	for (i = 0; i < count; i++)
 	    if ((lsa->map[i] & fcLangCountrySets[j][i]) &&
 		(lsb->map[i] & fcLangCountrySets[j][i]))
 	    {
@@ -508,7 +539,7 @@ FcLangSetHash (const FcLangSet *ls)
     FcChar32	h = 0;
     int		i;
 
-    for (i = 0; i < NUM_LANG_SET_MAP; i++)
+    for (i = 0; i < ls->map_size; i++)
 	h ^= ls->map[i];
     if (ls->extra)
 	h ^= ls->extra->num;
@@ -518,7 +549,7 @@ FcLangSetHash (const FcLangSet *ls)
 FcLangSet *
 FcNameParseLangSet (const FcChar8 *string)
 {
-    FcChar8	    lang[32],c;
+    FcChar8	    lang[32], c = 0;
     int i;
     FcLangSet	    *ls;
 
@@ -551,11 +582,12 @@ bail0:
 FcBool
 FcNameUnparseLangSet (FcStrBuf *buf, const FcLangSet *ls)
 {
-    int		i, bit;
+    int		i, bit, count;
     FcChar32	bits;
     FcBool	first = FcTrue;
 
-    for (i = 0; i < NUM_LANG_SET_MAP; i++)
+    count = FC_MIN (ls->map_size, NUM_LANG_SET_MAP);
+    for (i = 0; i < count; i++)
     {
 	if ((bits = ls->map[i]))
 	{
@@ -602,9 +634,11 @@ FcNameUnparseLangSet (FcStrBuf *buf, const FcLangSet *ls)
 FcBool
 FcLangSetEqual (const FcLangSet *lsa, const FcLangSet *lsb)
 {
-    int	    i;
+    int	    i, count;
 
-    for (i = 0; i < NUM_LANG_SET_MAP; i++)
+    count = FC_MIN (lsa->map_size, lsb->map_size);
+    count = FC_MIN (NUM_LANG_SET_MAP, count);
+    for (i = 0; i < count; i++)
     {
 	if (lsa->map[i] != lsb->map[i])
 	    return FcFalse;
@@ -672,7 +706,7 @@ FcLangSetContainsLang (const FcLangSet *ls, const FcChar8 *lang)
 FcBool
 FcLangSetContains (const FcLangSet *lsa, const FcLangSet *lsb)
 {
-    int		    i, j;
+    int		    i, j, count;
     FcChar32	    missing;
 
     if (FcDebug() & FC_DBG_MATCHV)
@@ -684,7 +718,9 @@ FcLangSetContains (const FcLangSet *lsa, const FcLangSet *lsb)
     /*
      * check bitmaps for missing language support
      */
-    for (i = 0; i < NUM_LANG_SET_MAP; i++)
+    count = FC_MIN (lsa->map_size, lsb->map_size);
+    count = FC_MIN (NUM_LANG_SET_MAP, count);
+    for (i = 0; i < count; i++)
     {
 	missing = lsb->map[i] & ~lsa->map[i];
 	if (missing)
@@ -742,6 +778,7 @@ FcLangSetSerialize(FcSerialize *serialize, const FcLangSet *l)
     if (!l_serialize)
 	return NULL;
     *l_serialize = *l;
+    l_serialize->extra = NULL; /* We don't serialize ls->extra */
     return l_serialize;
 }