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Repair insufficiently careful type checking for SQL-language functions:

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we should check that the function code returns the claimed result datatype
every time we parse the function for execution.  Formerly, for simple
scalar result types we assumed the creation-time check was sufficient, but
this fails if the function selects from a table that's been redefined since
then, and even more obviously fails if check_function_bodies had been OFF.

This is a significant security hole: not only can one trivially crash the
backend, but with appropriate misuse of pass-by-reference datatypes it is
possible to read out arbitrary locations in the server process's memory,
which could allow retrieving database content the user should not be able
to see.  Our thanks to Jeff Trout for the initial report.

Security: CVE-2007-0555
This commit is contained in:
Tom Lane
2007-02-02 00:04:16 +00:00
parent cf9ca3d2a3
commit 6be54294cb
3 changed files with 31 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
src/backend/catalog/pg_proc.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.94 2002/09/18 21:35:20 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.94.2.1 2007/02/02 00:04:16 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -33,7 +33,6 @@
#include "utils/syscache.h"
static void checkretval(Oid rettype, char fn_typtype, List *queryTreeList);
Datum fmgr_internal_validator(PG_FUNCTION_ARGS);
Datum fmgr_c_validator(PG_FUNCTION_ARGS);
Datum fmgr_sql_validator(PG_FUNCTION_ARGS);
@@ -294,15 +293,15 @@ ProcedureCreate(const char *procedureName,
}
/*
* checkretval() -- check return value of a list of sql parse trees.
* check_sql_fn_retval() -- check return value of a list of sql parse trees.
*
* The return value of a sql function is the value returned by
* the final query in the function. We do some ad-hoc define-time
* type checking here to be sure that the user is returning the
* type he claims.
*/
static void
checkretval(Oid rettype, char fn_typtype, List *queryTreeList)
void
check_sql_fn_retval(Oid rettype, char fn_typtype, List *queryTreeList)
{
Query *parse;
int cmd;
@@ -592,7 +591,7 @@ fmgr_sql_validator(PG_FUNCTION_ARGS)
prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
querytree_list = pg_parse_and_rewrite(prosrc, proc->proargtypes, proc->pronargs);
checkretval(proc->prorettype, functyptype, querytree_list);
check_sql_fn_retval(proc->prorettype, functyptype, querytree_list);
ReleaseSysCache(tuple);

30
src/backend/executor/functions.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/functions.c,v 1.57.2.1 2003/06/12 17:29:37 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/functions.c,v 1.57.2.2 2007/02/02 00:04:16 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -24,6 +24,7 @@
#include "tcop/tcopprot.h"
#include "tcop/utility.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
@@ -53,7 +54,7 @@ typedef struct local_es
typedef struct
{
int typlen; /* length of the return type */
int16 typlen; /* length of the return type */
bool typbyval; /* true if return type is pass by value */
bool returnsTuple; /* true if return type is a tuple */
bool shutdown_reg; /* true if registered shutdown callback */
@@ -71,7 +72,8 @@ typedef SQLFunctionCache *SQLFunctionCachePtr;
/* non-export function prototypes */
static execution_state *init_execution_state(char *src,
Oid *argOidVect, int nargs);
Oid *argOidVect, int nargs,
Oid rettype);
static void init_sql_fcache(FmgrInfo *finfo);
static void postquel_start(execution_state *es);
static TupleTableSlot *postquel_getnext(execution_state *es);
@@ -84,7 +86,8 @@ static void ShutdownSQLFunction(Datum arg);
static execution_state *
init_execution_state(char *src, Oid *argOidVect, int nargs)
init_execution_state(char *src, Oid *argOidVect, int nargs,
Oid rettype)
{
execution_state *firstes;
execution_state *preves;
@@ -93,6 +96,14 @@ init_execution_state(char *src, Oid *argOidVect, int nargs)
queryTree_list = pg_parse_and_rewrite(src, argOidVect, nargs);
/*
* Check that the function returns the type it claims to. Although
* this was already done when the function was defined,
* we have to recheck because database objects used in the function's
* queries might have changed type.
*/
check_sql_fn_retval(rettype, get_typtype(rettype), queryTree_list);
firstes = NULL;
preves = NULL;
@@ -150,6 +161,7 @@ static void
init_sql_fcache(FmgrInfo *finfo)
{
Oid foid = finfo->fn_oid;
Oid rettype;
HeapTuple procedureTuple;
HeapTuple typeTuple;
Form_pg_proc procedureStruct;
@@ -176,12 +188,14 @@ init_sql_fcache(FmgrInfo *finfo)
/*
* get the return type from the procedure tuple
*/
rettype = procedureStruct->prorettype;
typeTuple = SearchSysCache(TYPEOID,
ObjectIdGetDatum(procedureStruct->prorettype),
ObjectIdGetDatum(rettype),
0, 0, 0);
if (!HeapTupleIsValid(typeTuple))
elog(ERROR, "init_sql_fcache: Cache lookup failed for type %u",
procedureStruct->prorettype);
rettype);
typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);
@@ -194,7 +208,7 @@ init_sql_fcache(FmgrInfo *finfo)
fcache->typlen = typeStruct->typlen;
if (typeStruct->typtype != 'c' &&
procedureStruct->prorettype != RECORDOID)
rettype != RECORDOID)
{
/* The return type is not a composite type, so just use byval */
fcache->typbyval = typeStruct->typbyval;
@@ -243,7 +257,7 @@ init_sql_fcache(FmgrInfo *finfo)
foid);
src = DatumGetCString(DirectFunctionCall1(textout, tmp));
fcache->func_state = init_execution_state(src, argOidVect, nargs);
fcache->func_state = init_execution_state(src, argOidVect, nargs, rettype);
pfree(src);

5
src/include/catalog/pg_proc.h
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: pg_proc.h,v 1.275.2.3 2006/11/28 19:19:25 tgl Exp $
* $Id: pg_proc.h,v 1.275.2.4 2007/02/02 00:04:16 tgl Exp $
*
* NOTES
* The script catalog/genbki.sh reads this file and generates .bki
@@ -3150,4 +3150,7 @@ extern Oid ProcedureCreate(const char *procedureName,
int parameterCount,
const Oid *parameterTypes);
extern void check_sql_fn_retval(Oid rettype, char fn_typtype,
List *queryTreeList);
#endif /* PG_PROC_H */