From e4a6ebf7dece1481b1432c8ac43124487bebf3d9 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 7 Jan 2010 19:53:11 +0000
Subject: [PATCH] Make bit/varbit substring() treat any negative length as
meaning "all the rest of the string". The previous coding treated only -1
that way, and would produce an invalid result value for other negative
values.
We ought to fix it so that 2-parameter bit substring() is a different C
function and the 3-parameter form throws error for negative length, but
that takes a pg_proc change which is impractical in the back branches;
and in any case somebody might be relying on -1 working this way.
So just do this as a back-patchable fix.
---
src/backend/utils/adt/varbit.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/src/backend/utils/adt/varbit.c b/src/backend/utils/adt/varbit.c
index 6882231e617..d98a8a613ee 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 1.61 2010/01/07 04:53:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/varbit.c,v 1.62 2010/01/07 19:53:11 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -945,13 +945,23 @@ bitsubstr(PG_FUNCTION_ARGS)
*ps;
bitlen = VARBITLEN(arg);
- /* If we do not have an upper bound, set bitlen */
- if (l == -1)
- l = bitlen;
- e = s + l;
s1 = Max(s, 1);
- e1 = Min(e, bitlen + 1);
- if (s1 > bitlen || e1 < 1)
+ /* If we do not have an upper bound, use end of string */
+ if (l < 0)
+ {
+ e1 = bitlen + 1;
+ }
+ else
+ {
+ e = s + l;
+ /* guard against overflow, even though we don't allow L<0 here */
+ if (e < s)
+ ereport(ERROR,
+ (errcode(ERRCODE_SUBSTRING_ERROR),
+ errmsg("negative substring length not allowed")));
+ e1 = Min(e, bitlen + 1);
+ }
+ if (s1 > bitlen || e1 <= s1)
{
/* Need to return a zero-length bitstring */
len = VARBITTOTALLEN(0);
--
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