From 96462c3c064b296e04c151d6d0f2b05e605c6169 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 21 Aug 2007 02:40:18 +0000 Subject: [PATCH] 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 | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/src/backend/utils/adt/varbit.c b/src/backend/utils/adt/varbit.c index 22cab68903..b7641a0f9f 100644 --- a/src/backend/utils/adt/varbit.c +++ b/src/backend/utils/adt/varbit.c @@ -472,8 +472,9 @@ 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++) { @@ -481,11 +482,15 @@ 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'; -- 2.39.5