postgres.git / summary / log / commit / refs

commit    c2e2ad79890faa2429a8dab4a34a509ef79c05f9
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Tue Aug 21 02:40:26 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 bdbf43c8993..78708dd5648 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 1.44 2004/12/31 22:01:22 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/varbit.c,v 1.44.4.1 2007/08/21 02:40:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -430,8 +430,9 @@ 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++)
 		{
@@ -439,11 +440,15 @@ varbit_out(PG_FUNCTION_ARGS)
 			x <<= 1;
 		}
 	}
-	x = *sp;
-	for (k = i; k < len; k++)
+	if (i < len)
 	{
-		*r++ = (x & BITHIGH) ? '1' : '0';
-		x <<= 1;
+		/* print the last partial byte */
+		x = *sp;
+		for (k = i; k < len; k++)
+		{
+			*r++ = (x & BITHIGH) ? '1' : '0';
+			x <<= 1;
+		}
 	}
 	*r = '\0';
 


[parent: 5a3ec023120e]