postgres.git / summary / log / commit / refs

commit    1cee06ac02b0f12ba748c341a41cfd7fd1fb5ea9
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Tue Aug 21 02:40:06 2007 +0000
First released in: 8.3.0, 7.3.20, 7.4.18, 8.0.14, 8.1.10, 8.2.5

    Fix potential access-off-the-end-of-memory in varbit_out(): it fetched the
    byte after the last full byte of the bit array, regardless of whether that
    byte was part of the valid data or not.  Found by buildfarm testing.
    Thanks to Stefan Kaltenbrunner for nailing down the cause.


 src/backend/utils/adt/varbit.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/backend/utils/adt/varbit.c b/src/backend/utils/adt/varbit.c
index 3126bd689cb..b6ab6bb1e7f 100644
--- a/src/backend/utils/adt/varbit.c
+++ b/src/backend/utils/adt/varbit.c
@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/varbit.c,v 1.54 2007/06/15 20:56:51 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/varbit.c,v 1.55 2007/08/21 02:40:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -537,8 +537,9 @@ varbit_out(PG_FUNCTION_ARGS)
 	result = (char *) palloc(len + 1);
 	sp = VARBITS(s);
 	r = result;
-	for (i = 0; i < len - BITS_PER_BYTE; i += BITS_PER_BYTE, sp++)
+	for (i = 0; i <= len - BITS_PER_BYTE; i += BITS_PER_BYTE, sp++)
 	{
+		/* print full bytes */
 		x = *sp;
 		for (k = 0; k < BITS_PER_BYTE; k++)
 		{
@@ -546,11 +547,15 @@ varbit_out(PG_FUNCTION_ARGS)
 			x <<= 1;
 		}
 	}
-	x = *sp;
-	for (k = i; k < len; k++)
+	if (i < len)
 	{
-		*r++ = IS_HIGHBIT_SET(x) ? '1' : '0';
-		x <<= 1;
+		/* print the last partial byte */
+		x = *sp;
+		for (k = i; k < len; k++)
+		{
+			*r++ = IS_HIGHBIT_SET(x) ? '1' : '0';
+			x <<= 1;
+		}
 	}
 	*r = '\0';
 


[parent: 25a4a77985a3]