Remove libpq's PQescapeIdentifier(), not safe from injection attacks.

doc/src/sgml/libpq.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.212 2006/06/27 00:03:41 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.213 2006/07/04 13:22:15 momjian Exp $ -->
 
  <chapter id="libpq">
   <title><application>libpq</application> - C Library</title>
@@ -2279,68 +2279,6 @@ in favor of <function>PQescapeStringConn</>.
 </para>
 </sect2>
 
-<sect2 id="libpq-exec-escape-identifier">
-  <title>Escaping Identifier for Inclusion in SQL Commands</title>
-
-   <indexterm zone="libpq-exec-escape-identifier"><primary>PQescapeIdentifier</></>
-   <indexterm zone="libpq-exec-escape-identifier"><primary>escaping strings</></>
-
-<para>
-<function>PQescapeIdentifier</function> escapes a string for use 
-as an identifier name within an SQL command.  For example; table names,
-column names, view names and user names are all identifiers.
-Double quotes (") must be escaped to prevent them from being interpreted 
-specially by the SQL parser. <function>PQescapeIdentifier</> performs this 
-operation.
-</para>
-
-<tip>
-<para>
-It is especially important to do proper escaping when handling strings that
-were received from an untrustworthy source.  Otherwise there is a security
-risk: you are vulnerable to <quote>SQL injection</> attacks wherein unwanted
-SQL commands are fed to your database.
-</para>
-</tip>
-
-<para>
-Note that it is still necessary to do escaping of identifiers when
-using functions that support parameterized queries such as <function>PQexecParams</> or
-its sibling routines. Only literal values are automatically escaped
-using these functions, not identifiers.
-
-<synopsis>
-size_t PQescapeIdentifier (char *to, const char *from, size_t length);
-</synopsis>
-</para>
-
-<para>
-The parameter <parameter>from</> points to the first character of the
-string that is to be escaped, and the <parameter>length</> parameter
-gives the number of characters in this string. A terminating zero byte
-is not required, and should not be counted in <parameter>length</>. (If
-a terminating zero byte is found before <parameter>length</> bytes are
-processed, <function>PQescapeIdentifier</> stops at the zero; the
-behavior is thus rather like <function>strncpy</>.) <parameter>to</>
-shall point to a buffer that is able to hold at least one more character
-than twice the value of <parameter>length</>, otherwise the behavior is
-undefined. A call to <function>PQescapeIdentifier</> writes an escaped
-version of the <parameter>from</> string to the <parameter>to</> buffer,
-replacing special characters so that they cannot cause any harm, and
-adding a terminating zero byte. The double quotes that may surround
-<productname>PostgreSQL</> identifiers are not included in the result
-string; they should be provided in the SQL command that the result is
-inserted into.
-</para>
-<para>
-<function>PQescapeIdentifier</> returns the number of characters written
-to <parameter>to</>, not including the terminating zero byte.
-</para>
-<para>
-Behavior is undefined if the <parameter>to</> and <parameter>from</>
-strings overlap.
-</para>
-</sect2>
 
  <sect2 id="libpq-exec-escape-bytea">
   <title>Escaping Binary Strings for Inclusion in SQL Commands</title>

src/interfaces/libpq/exports.txt

@@ -1,4 +1,4 @@
-# $PostgreSQL: pgsql/src/interfaces/libpq/exports.txt,v 1.12 2006/06/27 00:03:41 momjian Exp $
+# $PostgreSQL: pgsql/src/interfaces/libpq/exports.txt,v 1.13 2006/07/04 13:22:15 momjian Exp $
 # Functions to be exported by libpq DLLs
 PQconnectdb               1
 PQsetdbLogin              2
@@ -130,5 +130,3 @@ PQescapeByteaConn         127
 PQencryptPassword         128
 PQisthreadsafe            129
 enlargePQExpBuffer        130
-PQescapeIdentifier        131
-

src/interfaces/libpq/fe-exec.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-exec.c,v 1.187 2006/06/27 00:03:41 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-exec.c,v 1.188 2006/07/04 13:22:15 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2515,42 +2515,6 @@ PQescapeString(char *to, const char *from, size_t length)
 								  static_std_strings);
 }
 
-/*
- * Escaping arbitrary strings to get valid SQL identifier strings.
- *
- * Replaces " with "".
- *
- * length is the length of the source string.  (Note: if a terminating NUL
- * is encountered sooner, PQescapeIdentifier stops short of "length"; the behavior
- * is thus rather like strncpy.)
- *
- * For safety the buffer at "to" must be at least 2*length + 1 bytes long.
- * A terminating NUL character is added to the output string, whether the
- * input is NUL-terminated or not.
- *
- * Returns the actual length of the output (not counting the terminating NUL).
- */
-size_t
-PQescapeIdentifier(char *to, const char *from, size_t length)
-{
-	const char *source = from;
-	char	   *target = to;
-	size_t		remaining = length;
-
-	while (remaining > 0 && *source != '\0')
-	{
-		if (*source  == '"')
-			*target++ = *source;
-		*target++ = *source++;
-		remaining--;
-	}
-
-	/* Write the terminating NUL character. */
-	*target = '\0';
-
-	return target - to;
-}
-
 /*
  *		PQescapeBytea	- converts from binary string to the
  *		minimal encoding necessary to include the string in an SQL

src/interfaces/libpq/libpq-fe.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.130 2006/06/27 00:03:42 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.131 2006/07/04 13:22:15 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -436,8 +436,6 @@ extern unsigned char *PQescapeByteaConn(PGconn *conn,
 				  size_t *to_length);
 extern unsigned char *PQunescapeBytea(const unsigned char *strtext,
 				size_t *retbuflen);
-extern size_t PQescapeIdentifier(char *to, const char *from, size_t length);
-
 /* These forms are deprecated! */
 extern size_t PQescapeString(char *to, const char *from, size_t length);
 extern unsigned char *PQescapeBytea(const unsigned char *from, size_t from_length,