render: NULL-protect SetPicturePictFilter()

Even though it shouldn't practically happen, better adding a trivial check,
just in case. The check is really cheap and possibly optimized-out.

| ../render/filter.c: In function ‘SetPicturePictFilter’:
| ../render/filter.c:388:36: warning: dereference of possibly-NULL ‘new_params’ [CWE-690] [-Wanalyzer-possible-null-dereference]
|   388 |         pPicture->filter_params[i] = params[i];
|       |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

render/filter.c

@@ -387,7 +387,8 @@ SetPicturePictFilter(PicturePtr pPicture, PictFilterPtr pFilter,
         pPicture->filter_nparams = nparams;
     }
     for (i = 0; i < nparams; i++)
-        pPicture->filter_params[i] = params[i];
+        if (pPicture->filter_params)
+            pPicture->filter_params[i] = params[i];
     pPicture->filter = pFilter->id;
 
     if (pPicture->pDrawable) {

render/glyph.c

@@ -123,6 +123,10 @@ FindGlyphRef(GlyphHashPtr hash,
     CARD32 elt, step, s;
     GlyphPtr glyph;
     GlyphRefPtr table, gr, del;
+
+    if ((hash == NULL) || (hash->hashSet == NULL))
+        return NULL;
+
     CARD32 tableSize = hash->hashSet->size;
 
     table = hash->table;
@@ -267,7 +271,7 @@ FreeGlyph(GlyphPtr glyph, int format)
         gr = FindGlyphRef(&globalGlyphs[format], signature, TRUE, glyph->sha1);
         if (gr - globalGlyphs[format].table != first)
             DuplicateRef(glyph, "Found wrong one");
-        if (gr->glyph && gr->glyph != DeletedGlyph) {
+        if (gr && gr->glyph && gr->glyph != DeletedGlyph) {
             gr->glyph = DeletedGlyph;
             gr->signature = 0;
             globalGlyphs[format].tableEntries--;
@@ -384,6 +388,7 @@ AllocateGlyph(xGlyphInfo * gi, int fdepth)
 static Bool
 AllocateGlyphHash(GlyphHashPtr hash, GlyphHashSetPtr hashSet)
 {
+    assert(hashSet);
     hash->table = calloc(hashSet->size, sizeof(GlyphRefRec));
     if (!hash->table)
         return FALSE;
@@ -418,10 +423,10 @@ ResizeGlyphHash(GlyphHashPtr hash, CARD32 change, Bool global)
             glyph = hash->table[i].glyph;
             if (glyph && glyph != DeletedGlyph) {
                 s = hash->table[i].signature;
-                gr = FindGlyphRef(&newHash, s, global, glyph->sha1);
-
-                gr->signature = s;
-                gr->glyph = glyph;
+                if ((gr = FindGlyphRef(&newHash, s, global, glyph->sha1))) {
+                    gr->signature = s;
+                    gr->glyph = glyph;
+                }
                 ++newHash.tableEntries;
             }
         }

render/picture.c

@@ -1013,7 +1013,10 @@ cpAlphaMap(void **result, XID id, ScreenPtr screen, ClientPtr client, Mask mode)
                                           client, mode);
         if (err != Success)
             return err;
-        id = res->info[screen->myNum].id;
+        if (screen == NULL)
+            LogMessage(X_WARNING, "cpAlphaMap() screen == NULL\n");
+        else
+            id = res->info[screen->myNum].id;
     }
 #endif /* XINERAMA */
     return dixLookupResourceByType(result, id, PictureType, client, mode);