Fix a *second* buffer overrun bug in to_ascii(). Grumble.

diff --git a/src/backend/utils/adt/ascii.c b/src/backend/utils/adt/ascii.c
index 9595876286b86dd6feb08767eb79a04b7f7f89c8..0091ead7d3b1003f4687114a647e8b1a76cb92f9 100644 (file)
--- a/src/backend/utils/adt/ascii.c
+++ b/src/backend/utils/adt/ascii.c
@@ -1,31 +1,31 @@
-/* -----------------------------------------------------------------------
+/*-----------------------------------------------------------------------
  * ascii.c
+ *  The PostgreSQL routine for string to ascii conversion.
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/adt/ascii.c,v 1.14 2003/04/02 21:07:59 tgl Exp $
- *
- *  Portions Copyright (c) 1999-2000, PostgreSQL Global Development Group
- *
+ *  Portions Copyright (c) 1999-2002, PostgreSQL Global Development Group
  *
- *  TO_ASCII()
+ * IDENTIFICATION
+ *   $Header: /cvsroot/pgsql/src/backend/utils/adt/ascii.c,v 1.15 2003/07/14 16:41:38 tgl Exp $
  *
- *  The PostgreSQL routine for string to ascii conversion.
- *
- * -----------------------------------------------------------------------
+ *-----------------------------------------------------------------------
  */
-
 #include "postgres.h"
+
 #include "utils/builtins.h"
 #include "mb/pg_wchar.h"
 #include "utils/ascii.h"
 
+static void pg_to_ascii(unsigned char *src, unsigned char *src_end,
+                       unsigned char *dest, int enc);
 static text *encode_to_ascii(text *data, int enc);
 
+
 /* ----------
  * to_ascii
  * ----------
  */
-char *
-pg_to_ascii(unsigned char *src, unsigned char *src_end, unsigned char *desc, int enc)
+static void
+pg_to_ascii(unsigned char *src, unsigned char *src_end, unsigned char *dest, int enc)
 {
    unsigned char *x;
    unsigned char *ascii;
@@ -37,7 +37,6 @@ pg_to_ascii(unsigned char *src, unsigned char *src_end, unsigned char *desc, int
 #define RANGE_128  128
 #define RANGE_160  160
 
-
    if (enc == PG_LATIN1)
    {
        /*
@@ -64,9 +63,9 @@ pg_to_ascii(unsigned char *src, unsigned char *src_end, unsigned char *desc, int
    }
    else
    {
-       elog(ERROR, "pg_to_ascii(): unsupported encoding from %s",
+       elog(ERROR, "unsupported encoding conversion from %s to ASCII",
             pg_encoding_to_char(enc));
-       return NULL;            /* keep compiler quiet */
+       return;                 /* keep compiler quiet */
    }
 
    /*
@@ -75,27 +74,27 @@ pg_to_ascii(unsigned char *src, unsigned char *src_end, unsigned char *desc, int
    for (x = src; x < src_end; x++)
    {
        if (*x < 128)
-           *desc++ = *x;
+           *dest++ = *x;
        else if (*x < range)
-           *desc++ = ' ';      /* bogus 128 to 'range' */
+           *dest++ = ' ';      /* bogus 128 to 'range' */
        else
-           *desc++ = ascii[*x - range];
+           *dest++ = ascii[*x - range];
    }
-
-   return desc;
 }
 
 /* ----------
  * encode text
+ *
+ * The text datum is overwritten in-place, therefore this coding method
+ * cannot support conversions that change the string length!
  * ----------
  */
 static text *
 encode_to_ascii(text *data, int enc)
 {
-   pg_to_ascii(
-               (unsigned char *) VARDATA(data),        /* src */
-               VARDATA(data) + VARSIZE(data),  /* src end */
-               (unsigned char *) VARDATA(data),        /* desc */
+   pg_to_ascii((unsigned char *) VARDATA(data),        /* src */
+               (unsigned char *) (data) + VARSIZE(data),   /* src end */
+               (unsigned char *) VARDATA(data),        /* dest */
                enc);           /* encoding */
 
    return data;
@@ -108,14 +107,10 @@ encode_to_ascii(text *data, int enc)
 Datum
 to_ascii_encname(PG_FUNCTION_ARGS)
 {
-   PG_RETURN_TEXT_P
-       (
-        encode_to_ascii
-        (
-         PG_GETARG_TEXT_P_COPY(0),
-         pg_char_to_encoding(NameStr(*PG_GETARG_NAME(1)))
-         )
-       );
+   text   *data = PG_GETARG_TEXT_P_COPY(0);
+   int     enc = pg_char_to_encoding(NameStr(*PG_GETARG_NAME(1)));
+
+   PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
 }
 
 /* ----------
@@ -125,14 +120,10 @@ to_ascii_encname(PG_FUNCTION_ARGS)
 Datum
 to_ascii_enc(PG_FUNCTION_ARGS)
 {
-   PG_RETURN_TEXT_P
-       (
-        encode_to_ascii
-        (
-         PG_GETARG_TEXT_P_COPY(0),
-         PG_GETARG_INT32(1)
-         )
-       );
+   text   *data = PG_GETARG_TEXT_P_COPY(0);
+   int     enc = PG_GETARG_INT32(1);
+
+   PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
 }
 
 /* ----------
@@ -142,12 +133,8 @@ to_ascii_enc(PG_FUNCTION_ARGS)
 Datum
 to_ascii_default(PG_FUNCTION_ARGS)
 {
-   PG_RETURN_TEXT_P
-       (
-        encode_to_ascii
-        (
-         PG_GETARG_TEXT_P_COPY(0),
-         GetDatabaseEncoding()
-         )
-       );
+   text   *data = PG_GETARG_TEXT_P_COPY(0);
+   int     enc = GetDatabaseEncoding();
+
+   PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
 }