-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.58 2006/05/11 19:15:35 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.59 2006/05/21 20:10:42 tgl Exp $ -->
<chapter Id="runtime-config">
<title>Server Configuration</title>
</listitem>
</varlistentry>
+ <varlistentry id="guc-backslash-quote" xreflabel="backslash_quote">
+ <term><varname>backslash_quote</varname> (<type>string</type>)</term>
+ <indexterm><primary>strings</><secondary>backslash quotes</></>
+ <indexterm>
+ <primary><varname>backslash_quote</> configuration parameter</primary>
+ </indexterm>
+ <listitem>
+ <para>
+ This controls whether a quote mark can be represented by
+ <literal>\'</> in a string literal. The preferred, SQL-standard way
+ to represent a quote mark is by doubling it (<literal>''</>) but
+ <productname>PostgreSQL</> has historically also accepted
+ <literal>\'</>. However, use of <literal>\'</> creates security risks
+ because in some client character set encodings, there are multibyte
+ characters in which the last byte is numerically equivalent to ASCII
+ <literal>\</>. If client-side code does escaping incorrectly then a
+ SQL-injection attack is possible. This risk can be prevented by
+ making the server reject queries in which a quote mark appears to be
+ escaped by a backslash.
+ The allowed values of <varname>backslash_quote</> are
+ <literal>on</> (allow <literal>\'</> always),
+ <literal>off</> (reject always), and
+ <literal>safe_encoding</> (allow only if client encoding does not
+ allow ASCII <literal>\</> within a multibyte character).
+ <literal>safe_encoding</> is the default setting.
+ </para>
+
+ <para>
+ Note that in a standard-conforming string literal, <literal>\</> just
+ means <literal>\</> anyway. This parameter affects the handling of
+ non-standard-conforming literals, including
+ escape string syntax (<literal>E'...'</>).
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-default-with-oids" xreflabel="default_with_oids">
<term><varname>default_with_oids</varname> (<type>boolean</type>)</term>
<indexterm>
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/parser/scan.l,v 1.134 2006/05/11 19:15:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/scan.l,v 1.135 2006/05/21 20:10:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
* But we shall have to live with it as a short-term thing until the switch
* to SQL-standard string syntax is complete.
*/
+BackslashQuoteType backslash_quote = BACKSLASH_QUOTE_SAFE_ENCODING;
bool escape_string_warning = true;
bool standard_conforming_strings = false;
addlit(yytext, yyleng);
}
<xe>{xeescape} {
+ if (yytext[1] == '\'')
+ {
+ if (backslash_quote == BACKSLASH_QUOTE_OFF ||
+ (backslash_quote == BACKSLASH_QUOTE_SAFE_ENCODING &&
+ PG_ENCODING_IS_CLIENT_ONLY(pg_get_client_encoding())))
+ ereport(ERROR,
+ (errcode(ERRCODE_NONSTANDARD_USE_OF_ESCAPE_CHARACTER),
+ errmsg("unsafe use of \\' in a string literal"),
+ errhint("Use '' to write quotes in strings. \\' is insecure in client-only encodings."),
+ lexer_errposition()));
+ }
check_string_escape_warning(yytext[1]);
addlitchar(unescape_single_char(yytext[1]));
}
* Written by Peter Eisentraut <peter_e@gmx.net>.
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.319 2006/05/11 19:15:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.320 2006/05/21 20:10:42 tgl Exp $
*
*--------------------------------------------------------------------
*/
static bool assign_log_stats(bool newval, bool doit, GucSource source);
static bool assign_transaction_read_only(bool newval, bool doit, GucSource source);
static const char *assign_canonical_path(const char *newval, bool doit, GucSource source);
+static const char *assign_backslash_quote(const char *newval, bool doit, GucSource source);
static bool assign_tcp_keepalives_idle(int newval, bool doit, GucSource source);
static bool assign_tcp_keepalives_interval(int newval, bool doit, GucSource source);
static bool phony_autocommit;
static bool session_auth_is_superuser;
static double phony_random_seed;
+static char *backslash_quote_string;
static char *client_encoding_string;
static char *datestyle_string;
static char *default_iso_level_string;
"", NULL, NULL
},
+ {
+ {"backslash_quote", PGC_USERSET, COMPAT_OPTIONS_PREVIOUS,
+ gettext_noop("Sets whether \"\\'\" is allowed in string literals."),
+ gettext_noop("Valid values are ON, OFF, and SAFE_ENCODING.")
+ },
+ &backslash_quote_string,
+ "safe_encoding", assign_backslash_quote, NULL
+ },
+
{
{"client_encoding", PGC_USERSET, CLIENT_CONN_LOCALE,
gettext_noop("Sets the client's character set encoding."),
return newval;
}
+static const char *
+assign_backslash_quote(const char *newval, bool doit, GucSource source)
+{
+ BackslashQuoteType bq;
+ bool bqbool;
+
+ /*
+ * Although only "on", "off", and "safe_encoding" are documented,
+ * we use parse_bool so we can accept all the likely variants of
+ * "on" and "off".
+ */
+ if (pg_strcasecmp(newval, "safe_encoding") == 0)
+ bq = BACKSLASH_QUOTE_SAFE_ENCODING;
+ else if (parse_bool(newval, &bqbool))
+ {
+ bq = bqbool ? BACKSLASH_QUOTE_ON : BACKSLASH_QUOTE_OFF;
+ }
+ else
+ return NULL; /* reject */
+
+ if (doit)
+ backslash_quote = bq;
+
+ return newval;
+}
+
static bool
assign_tcp_keepalives_idle(int newval, bool doit, GucSource source)
{
#add_missing_from = off
#array_nulls = on
+#backslash_quote = safe_encoding # on, off, or safe_encoding
#default_with_oids = off
#escape_string_warning = on
#standard_conforming_strings = off
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/parser/gramparse.h,v 1.35 2006/05/11 19:15:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/gramparse.h,v 1.36 2006/05/21 20:10:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
*/
#define YYLTYPE int
+typedef enum
+{
+ BACKSLASH_QUOTE_OFF,
+ BACKSLASH_QUOTE_ON,
+ BACKSLASH_QUOTE_SAFE_ENCODING
+} BackslashQuoteType;
+
/* GUC variables in scan.l (every one of these is a bad idea :-() */
+extern BackslashQuoteType backslash_quote;
extern bool escape_string_warning;
extern bool standard_conforming_strings;
projects / postgresql / commitdiff