Backported CORE-6528: Connect to database that contains broken pages can lead to FB crash

AlexPeshkoff · AlexPeshkoff · commit 2573f141ad37 · 2021-03-31T18:34:03.000+03:00
diff --git a/src/jrd/btr.cpp b/src/jrd/btr.cpp
@@ -4062,7 +4062,36 @@ static index_root_page* fetch_root(thread_db* tdbb, WIN* window, const jrd_rel*
 		window->win_page = relPages->rel_index_root;
 	}
 
-	return (index_root_page*) CCH_FETCH(tdbb, window, LCK_read, pag_root);
+	index_root_page* irp = (index_root_page*) CCH_FETCH(tdbb, window, LCK_read, pag_root);
+	if (irp)
+	{
+		// check RPT size correctness
+		FB_UINT64 rptSize = sizeof(index_root_page) - sizeof(index_root_page::irt_repeat);
+		rptSize += FB_UINT64(irp->irt_count) * sizeof(index_root_page::irt_repeat);
+		if (rptSize > tdbb->getDatabase()->dbb_page_size)
+		{
+			CCH_RELEASE(tdbb, window);
+			(Arg::Gds(isc_random) << "Bad index root page: too many indices").raise();
+		}
+
+		// check keys location on page
+		for (USHORT i = 0; i < irp->irt_count; ++i)
+		{
+			index_root_page::irt_repeat* irt = &irp->irt_rpt[i];
+			if (!irt->getRoot())
+				continue;
+
+			FB_UINT64 descEnd = irt->irt_desc;
+			descEnd += FB_UINT64(irt->irt_keys) * sizeof(irtd);
+			if (descEnd > tdbb->getDatabase()->dbb_page_size)
+			{
+				CCH_RELEASE(tdbb, window);
+				(Arg::Gds(isc_random) << "Bad index root page: keys run out of page").raise();
+			}
+		}
+	}
+
+	return irp;
 }
 
 
