From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Tue, 30 Jun 2015 10:44:04 +0000 (+0300)
Subject: Add assertion to check the special size is sane before dereferencing it.
X-Git-Tag: REL9_5_ALPHA2~162
X-Git-Url: http://git.postgresql.org/gitweb/-?a=commitdiff_plain;h=302ac7f27197855afa8c89fae36c85c124ae156b;p=postgresql-pgindent.git

Add assertion to check the special size is sane before dereferencing it.

This seems useful to catch errors of the sort I just fixed, where
PageGetSpecialPointer is called before initializing the page.
---

diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index c2fbffc8e9..a2f78ee56c 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -304,6 +304,8 @@ typedef PageHeaderData *PageHeader;
 #define PageGetSpecialPointer(page) \
 ( \
 	AssertMacro(PageIsValid(page)), \
+	AssertMacro(((PageHeader) (page))->pd_special <= BLCKSZ), \
+	AssertMacro(((PageHeader) (page))->pd_special >= SizeOfPageHeaderData), \
 	(char *) ((char *) (page) + ((PageHeader) (page))->pd_special) \
 )