*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.198.2.3 2010/06/30 18:11:04 heikki Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.198.2.4 2010/07/30 17:57:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-#include "catalog/pg_attrdef.h"
-#include "catalog/pg_constraint.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "mb/pg_wchar.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
-#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
{
List *targs;
ListCell *args;
- Node *result;
/*
* Transform the list of arguments. We use a shallow list copy and then
(Node *) lfirst(args));
}
- result = ParseFuncOrColumn(pstate,
+ return ParseFuncOrColumn(pstate,
fn->funcname,
targs,
fn->agg_star,
fn->agg_distinct,
false,
fn->location);
-
- /*
- * pg_get_expr() is a system function that exposes the expression
- * deparsing functionality in ruleutils.c to users. Very handy, but
- * it was later realized that the functions in ruleutils.c don't check
- * the input rigorously, assuming it to come from system catalogs and
- * to therefore be valid. That makes it easy for a user to crash the
- * backend by passing a maliciously crafted string representation of
- * an expression to pg_get_expr().
- *
- * There's a lot of code in ruleutils.c, so it's not feasible to add
- * water-proof input checking after the fact. Even if we did it once,
- * it would need to be taken into account in any future es too.
- *
- * Instead, we restrict pg_rule_expr() to only allow input from system
- * catalogs instead. This is a hack, but it's the most robust and easiest
- * to back way of plugging the vulnerability.
- *
- * This is transparent to the typical usage pattern of
- * "pg_get_expr(systemcolumn, ...)", but will break
- * "pg_get_expr('foo', ...)", even if 'foo' is a valid expression fetched
- * earlier from a system catalog. Hopefully there's isn't many clients
- * doing that out there.
- */
- if (result && IsA(result, FuncExpr) && !superuser())
- {
- FuncExpr *fe = (FuncExpr *) result;
- if (fe->funcid == F_PG_GET_EXPR || fe->funcid == F_PG_GET_EXPR_EXT)
- {
- Expr *arg = linitial(fe->args);
- bool allowed = false;
-
- /*
- * Check that the argument came directly from one of the
- * allowed system catalog columns
- */
- if (IsA(arg, Var))
- {
- Var *var = (Var *) arg;
- RangeTblEntry *rte;
-
- rte = GetRTEByRangeTablePosn(pstate,
- var->varno, var->varlevelsup);
-
- switch(rte->relid)
- {
- case IndexRelationId:
- if (var->varattno == Anum_pg_index_indexprs ||
- var->varattno == Anum_pg_index_indpred)
- allowed = true;
- break;
-
- case AttrDefaultRelationId:
- if (var->varattno == Anum_pg_attrdef_adbin)
- allowed = true;
- break;
-
- case ConstraintRelationId:
- if (var->varattno == Anum_pg_constraint_conbin)
- allowed = true;
- break;
-
- case TypeRelationId:
- if (var->varattno == Anum_pg_type_typdefaultbin)
- allowed = true;
- break;
- }
- }
- if (!allowed)
- ereport(ERROR,
- (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
- errmsg("argument to pg_get_expr() must come from system catalogs")));
- }
- }
- return result;
}
static Node *
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.190 2006/10/04 00:29:55 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.190.2.1 2010/07/30 17:57:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
+#include "catalog/pg_attrdef.h"
+#include "catalog/pg_constraint.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
+#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "parser/parse_agg.h"
#include "parser/parse_coerce.h"
parser_errposition(pstate, location)));
}
+ /* Hack to protect pg_get_expr() against misuse */
+ check_pg_get_expr_args(pstate, funcid, fargs);
+
return retval;
}
return oid;
}
+
+
+/*
+ * pg_get_expr() is a system function that exposes the expression
+ * deparsing functionality in ruleutils.c to users. Very handy, but it was
+ * later realized that the functions in ruleutils.c don't check the input
+ * rigorously, assuming it to come from system catalogs and to therefore
+ * be valid. That makes it easy for a user to crash the backend by passing
+ * a maliciously crafted string representation of an expression to
+ * pg_get_expr().
+ *
+ * There's a lot of code in ruleutils.c, so it's not feasible to add
+ * water-proof input checking after the fact. Even if we did it once, it
+ * would need to be taken into account in any future es too.
+ *
+ * Instead, we restrict pg_rule_expr() to only allow input from system
+ * catalogs. This is a hack, but it's the most robust and easiest
+ * to back way of plugging the vulnerability.
+ *
+ * This is transparent to the typical usage pattern of
+ * "pg_get_expr(systemcolumn, ...)", but will break "pg_get_expr('foo',
+ * ...)", even if 'foo' is a valid expression fetched earlier from a
+ * system catalog. Hopefully there aren't many clients doing that out there.
+ */
+void
+check_pg_get_expr_args(ParseState *pstate, Oid fnoid, List *args)
+{
+ bool allowed = false;
+ Node *arg;
+ int netlevelsup;
+
+ /* if not being called for pg_get_expr, do nothing */
+ if (fnoid != F_PG_GET_EXPR && fnoid != F_PG_GET_EXPR_EXT)
+ return;
+
+ /* superusers are allowed to call it anyway (dubious) */
+ if (superuser())
+ return;
+
+ /*
+ * The first argument must be a Var referencing one of the allowed
+ * system-catalog columns. It could be a join alias Var, though.
+ */
+ Assert(list_length(args) > 1);
+ arg = (Node *) linitial(args);
+ netlevelsup = 0;
+
+restart:
+ if (IsA(arg, Var))
+ {
+ Var *var = (Var *) arg;
+ RangeTblEntry *rte;
+
+ netlevelsup += var->varlevelsup;
+ rte = GetRTEByRangeTablePosn(pstate, var->varno, netlevelsup);
+
+ if (rte->rtekind == RTE_JOIN)
+ {
+ /* Expand join alias reference */
+ if (var->varattno > 0 &&
+ var->varattno <= list_length(rte->joinaliasvars))
+ {
+ arg = (Node *) list_nth(rte->joinaliasvars, var->varattno - 1);
+ goto restart;
+ }
+ }
+ else if (rte->rtekind == RTE_RELATION)
+ {
+ switch (rte->relid)
+ {
+ case IndexRelationId:
+ if (var->varattno == Anum_pg_index_indexprs ||
+ var->varattno == Anum_pg_index_indpred)
+ allowed = true;
+ break;
+
+ case AttrDefaultRelationId:
+ if (var->varattno == Anum_pg_attrdef_adbin)
+ allowed = true;
+ break;
+
+ case ConstraintRelationId:
+ if (var->varattno == Anum_pg_constraint_conbin)
+ allowed = true;
+ break;
+
+ case TypeRelationId:
+ if (var->varattno == Anum_pg_type_typdefaultbin)
+ allowed = true;
+ break;
+ }
+ }
+ }
+
+ if (!allowed)
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("argument to pg_get_expr() must come from system catalogs")));
+}
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/parser/parse_oper.c,v 1.90 2006/10/04 00:29:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/parser/parse_oper.c,v 1.90.2.1 2010/07/30 17:57:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
result->useOr = useOr;
result->args = args;
+ /* Hack to protect pg_get_expr() against misuse */
+ check_pg_get_expr_args(pstate, opform->oprcode, args);
+
ReleaseSysCache(tup);
return (Expr *) result;
result->opretset = get_func_retset(opform->oprcode);
result->args = args;
+ /* Hack to protect pg_get_expr() against misuse */
+ check_pg_get_expr_args(pstate, opform->oprcode, args);
+
return (Expr *) result;
}
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.57 2006/10/04 00:30:09 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.57.2.1 2010/07/30 17:57:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
extern Oid LookupAggNameTypeNames(List *aggname, List *argtypes,
bool noError);
+extern void check_pg_get_expr_args(ParseState *pstate, Oid fnoid, List *args);
+
#endif /* PARSE_FUNC_H */
projects / users / gsingh / postgres.git / commitdiff