Replace argument-checking Asserts with regular test-and-elog checks in all

encoding conversion functions.  These are not can't-happen cases because
it's possible to create a conversion with the wrong conversion function
for the specified encoding pair.  That would lead to an Assert crash in
an Assert-enabled build, or incorrect conversion otherwise, neither of
which is desirable.  This would be a DOS issue if production databases
were customarily built with asserts enabled, but fortunately that's not so.
Per an observation by Heikki.

Back-patch to all supported branches.

1 files changed, 34 insertions, 1 deletions

diff --git a/src/backend/utils/mb/wchar.c b/src/backend/utils/mb/wchar.c
index 5e841629d82..f2206902f41 100644
--- a/src/backend/utils/mb/wchar.c
+++ b/src/backend/utils/mb/wchar.c
@@ -1,7 +1,7 @@
 /*
  * conversion functions between pg_wchar and multibyte streams.
  * Tatsuo Ishii
- * $PostgreSQL: pgsql/src/backend/utils/mb/wchar.c,v 1.47.2.7 2008/10/27 19:37:42 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/mb/wchar.c,v 1.47.2.8 2009/01/29 19:24:37 tgl Exp $
  *
  * WIN1250 client encoding updated by Pavel Behal
  *
@@ -1327,6 +1327,39 @@ pg_verify_mbstr(int encoding, const char *mbstr, int len, bool noError)
 }
 
 /*
+ * check_encoding_conversion_args: check arguments of a conversion function
+ *
+ * "expected" arguments can be either an encoding ID or -1 to indicate that
+ * the caller will check whether it accepts the ID.
+ *
+ * Note: the errors here are not really user-facing, so elog instead of
+ * ereport seems sufficient.  Also, we trust that the "expected" encoding
+ * arguments are valid encoding IDs, but we don't trust the actuals.
+ */
+void
+check_encoding_conversion_args(int src_encoding,
+							   int dest_encoding,
+							   int len,
+							   int expected_src_encoding,
+							   int expected_dest_encoding)
+{
+	if (!PG_VALID_ENCODING(src_encoding))
+		elog(ERROR, "invalid source encoding ID: %d", src_encoding);
+	if (src_encoding != expected_src_encoding && expected_src_encoding >= 0)
+		elog(ERROR, "expected source encoding \"%s\", but got \"%s\"",
+			 pg_enc2name_tbl[expected_src_encoding].name,
+			 pg_enc2name_tbl[src_encoding].name);
+	if (!PG_VALID_ENCODING(dest_encoding))
+		elog(ERROR, "invalid destination encoding ID: %d", dest_encoding);
+	if (dest_encoding != expected_dest_encoding && expected_dest_encoding >= 0)
+		elog(ERROR, "expected destination encoding \"%s\", but got \"%s\"",
+			 pg_enc2name_tbl[expected_dest_encoding].name,
+			 pg_enc2name_tbl[dest_encoding].name);
+	if (len < 0)
+		elog(ERROR, "encoding conversion length must not be negative");
+}
+
+/*
  * report_invalid_encoding: complain about invalid multibyte character
  *
  * note: len is remaining length of string, not length of character;