Propagate enlargeStringInfo() fixes into the equivalent code in

pqexpbuffer.c.  While a client-side failure doesn't seem like a
security issue, it's still a bug.

diff --git a/src/interfaces/libpq/pqexpbuffer.c b/src/interfaces/libpq/pqexpbuffer.c
index 195f6cfd6b9bc9813d86210f8982219a007e2dd3..27b99a279ba62e110889e766b1d67496dc7a8853 100644 (file)
--- a/src/interfaces/libpq/pqexpbuffer.c
+++ b/src/interfaces/libpq/pqexpbuffer.c
@@ -17,13 +17,15 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/interfaces/libpq/pqexpbuffer.c,v 1.15 2003/08/04 02:40:20 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/interfaces/libpq/pqexpbuffer.c,v 1.15.4.1 2004/05/14 00:20:51 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 
 #include "postgres_fe.h"
 
+#include <limits.h>
+
 #include "pqexpbuffer.h"
 
 #ifdef WIN32
@@ -132,7 +134,18 @@ enlargePQExpBuffer(PQExpBuffer str, size_t needed)
    size_t      newlen;
    char       *newdata;
 
+   /*
+    * Guard against ridiculous "needed" values, which can occur if we're
+    * fed bogus data.  Without this, we can get an overflow or infinite
+    * loop in the following.
+    */
+   if (needed >= ((size_t) INT_MAX - str->len))
+       return 0;
+
    needed += str->len + 1;     /* total space required now */
+
+   /* Because of the above test, we now have needed <= INT_MAX */
+
    if (needed <= str->maxlen)
        return 1;               /* got enough space already */
 
@@ -146,6 +159,14 @@ enlargePQExpBuffer(PQExpBuffer str, size_t needed)
    while (needed > newlen)
        newlen = 2 * newlen;
 
+   /*
+    * Clamp to INT_MAX in case we went past it.  Note we are assuming
+    * here that INT_MAX <= UINT_MAX/2, else the above loop could
+    * overflow.  We will still have newlen >= needed.
+    */
+   if (newlen > (size_t) INT_MAX)
+       newlen = (size_t) INT_MAX;
+
    newdata = (char *) realloc(str->data, newlen);
    if (newdata != NULL)
    {