From fbcc69c192a07bd25ac257164f24828a280f7f32 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 6 Jul 2008 19:48:45 +0000
Subject: [PATCH] Prevent integer overflows during units conversion when
displaying a GUC variable that has units. Per report from Stefan
Kaltenbrunner.
Backport to 8.2. I also backported my patch of 2007-06-21 that prevented
comparable overflows on the input side, since that now seems to have enough
field track record to be back-patched safely. That patch included addition
of hints listing the available unit names, which I did not bother to strip
out of it --- this will make a little more work for the translators, but
they can copy the translation from 8.3, and anyway an untranslated hint
is better than no hint.
---
src/backend/utils/misc/guc.c | 41 ++++++++++++++++++++++--------------
1 file changed, 25 insertions(+), 16 deletions(-)
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 60b2fead7d7..96e05fdc232 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
* Written by Peter Eisentraut <peter_e@gmx.net>.
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.461 2008/07/01 21:07:33 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.462 2008/07/06 19:48:45 tgl Exp $
*
*--------------------------------------------------------------------
*/
@@ -6266,10 +6266,18 @@ _ShowOption(struct config_generic * record, bool use_units)
val = (*conf->show_hook) ();
else
{
- char unit[4];
- int result = *conf->variable;
+ /*
+ * Use int64 arithmetic to avoid overflows in units
+ * conversion. If INT64_IS_BUSTED we might overflow
+ * anyway and print bogus answers, but there are few
+ * enough such machines that it doesn't seem worth
+ * trying harder.
+ */
+ int64 result = *conf->variable;
+ const char *unit;
- if (use_units && result > 0 && (record->flags & GUC_UNIT_MEMORY))
+ if (use_units && result > 0 &&
+ (record->flags & GUC_UNIT_MEMORY))
{
switch (record->flags & GUC_UNIT_MEMORY)
{
@@ -6284,19 +6292,20 @@ _ShowOption(struct config_generic * record, bool use_units)
if (result % KB_PER_GB == 0)
{
result /= KB_PER_GB;
- strcpy(unit, "GB");
+ unit = "GB";
}
else if (result % KB_PER_MB == 0)
{
result /= KB_PER_MB;
- strcpy(unit, "MB");
+ unit = "MB";
}
else
{
- strcpy(unit, "kB");
+ unit = "kB";
}
}
- else if (use_units && result > 0 && (record->flags & GUC_UNIT_TIME))
+ else if (use_units && result > 0 &&
+ (record->flags & GUC_UNIT_TIME))
{
switch (record->flags & GUC_UNIT_TIME)
{
@@ -6311,33 +6320,33 @@ _ShowOption(struct config_generic * record, bool use_units)
if (result % MS_PER_D == 0)
{
result /= MS_PER_D;
- strcpy(unit, "d");
+ unit = "d";
}
else if (result % MS_PER_H == 0)
{
result /= MS_PER_H;
- strcpy(unit, "h");
+ unit = "h";
}
else if (result % MS_PER_MIN == 0)
{
result /= MS_PER_MIN;
- strcpy(unit, "min");
+ unit = "min";
}
else if (result % MS_PER_S == 0)
{
result /= MS_PER_S;
- strcpy(unit, "s");
+ unit = "s";
}
else
{
- strcpy(unit, "ms");
+ unit = "ms";
}
}
else
- strcpy(unit, "");
+ unit = "";
- snprintf(buffer, sizeof(buffer), "%d%s",
- (int) result, unit);
+ snprintf(buffer, sizeof(buffer), INT64_FORMAT "%s",
+ result, unit);
val = buffer;
}
}
--
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