Reject out-of-range numeric timezone specifications.

tglsfdc · tglsfdc · commit f54d97c5ef58 · 2014-07-21T22:41:30.000-04:00
In commit 631dc39, we started to handle simple numeric timezone offsets via the zic library instead of the old CTimeZone/HasCTZSet kluge. However, we overlooked the fact that the zic code will reject UTC offsets exceeding a week (which seems a bit arbitrary, but not because it's too tight ...). This led to possibly setting session_timezone to NULL, which results in crashes in most timezone-related operations as of 9.4, and crashes in a small number of places even before that. So check for NULL return from pg_tzset_offset() and report an appropriate error message. Per bug #11014 from Duncan Gillis. Back-patch to all supported branches, like the previous patch. (Unfortunately, as of today that no longer includes 8.4.)
diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
@@ -372,6 +372,13 @@ check_timezone(char **newval, void **extra, GucSource source)
 		}
 	}
 
+	/* Test for failure in pg_tzset_offset, which we assume is out-of-range */
+	if (!myextra.session_timezone)
+	{
+		GUC_check_errdetail("UTC timezone offset is out of range.");
+		return false;
+	}
+
 	/*
 	 * Prepare the canonical string to return.  GUC wants it malloc'd.
 	 *
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
@@ -296,6 +296,9 @@ pg_tzset(const char *name)
  * The GMT offset is specified in seconds, positive values meaning west of
  * Greenwich (ie, POSIX not ISO sign convention).  However, we use ISO
  * sign convention in the displayable abbreviation for the zone.
+ *
+ * Caution: this can fail (return NULL) if the specified offset is outside
+ * the range allowed by the zic library.
  */
 pg_tz *
 pg_tzset_offset(long gmtoffset)

Original file line number	Diff line number	Diff line change
`@@ -372,6 +372,13 @@ check_timezone(char newval, void extra, GucSource source)`
`372`	`372`	`}`
`373`	`373`	`}`
`374`	`374`
	`375`	`+ /* Test for failure in pg_tzset_offset, which we assume is out-of-range */`
	`376`	`+ if (!myextra.session_timezone)`
	`377`	`+ {`
	`378`	`+ GUC_check_errdetail("UTC timezone offset is out of range.");`
	`379`	`+ return false;`
	`380`	`+ }`
	`381`	`+`
`375`	`382`	`/*`
`376`	`383`	`* Prepare the canonical string to return. GUC wants it malloc'd.`
`377`	`384`	`*`