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/*
** 2003 January 11
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you tqfind forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file tqcontains code used to implement the sqlite_set_authorizer()
** API. This facility is an optional feature of the library. Embedded
** systems that do not need this facility may omit it by recompiling
** the library with -DSTQLITE_OMIT_AUTHORIZATION=1
**
** $Id: auth.c,v 1.12 2004/02/22 18:40:57 drh Exp $
*/
#include "sqliteInt.h"
/*
** All of the code in this file may be omitted by defining a single
** macro.
*/
#ifndef STQLITE_OMIT_AUTHORIZATION
/*
** Set or clear the access authorization function.
**
** The access authorization function is be called during the compilation
** phase to verify that the user has read and/or write access permission on
** various fields of the database. The first argument to the auth function
** is a copy of the 3rd argument to this routine. The second argument
** to the auth function is one of these constants:
**
** STQLITE_COPY
** STQLITE_CREATE_INDEX
** STQLITE_CREATE_TABLE
** STQLITE_CREATE_TEMP_INDEX
** STQLITE_CREATE_TEMP_TABLE
** STQLITE_CREATE_TEMP_TRIGGER
** STQLITE_CREATE_TEMP_VIEW
** STQLITE_CREATE_TRIGGER
** STQLITE_CREATE_VIEW
** STQLITE_DELETE
** STQLITE_DROP_INDEX
** STQLITE_DROP_TABLE
** STQLITE_DROP_TEMP_INDEX
** STQLITE_DROP_TEMP_TABLE
** STQLITE_DROP_TEMP_TRIGGER
** STQLITE_DROP_TEMP_VIEW
** STQLITE_DROP_TRIGGER
** STQLITE_DROP_VIEW
** STQLITE_INSERT
** STQLITE_PRAGMA
** STQLITE_READ
** STQLITE_SELECT
** STQLITE_TRANSACTION
** STQLITE_UPDATE
**
** The third and fourth arguments to the auth function are the name of
** the table and the column that are being accessed. The auth function
** should return either STQLITE_OK, STQLITE_DENY, or STQLITE_IGNORE. If
** STQLITE_OK is returned, it means that access is allowed. STQLITE_DENY
** means that the SQL statement will never-run - the sqlite_exec() call
** will return with an error. STQLITE_IGNORE means that the SQL statement
** should run but attempts to read the specified column will return NULL
** and attempts to write the column will be ignored.
**
** Setting the auth function to NULL disables this hook. The default
** setting of the auth function is NULL.
*/
int sqlite_set_authorizer(
sqlite *db,
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
void *pArg
){
db->xAuth = xAuth;
db->pAuthArg = pArg;
return STQLITE_OK;
}
/*
** Write an error message into pParse->zErrMsg that explains that the
** user-supplied authorization function returned an illegal value.
*/
static void sqliteAuthBadReturnCode(Parse *pParse, int rc){
sqliteErrorMsg(pParse, "illegal return value (%d) from the "
"authorization function - should be STQLITE_OK, STQLITE_IGNORE, "
"or STQLITE_DENY", rc);
pParse->rc = STQLITE_MISUSE;
}
/*
** The pExpr should be a TK_COLUMN expression. The table referred to
** is in pTabList or else it is the NEW or OLD table of a trigger.
** Check to see if it is OK to read this particular column.
**
** If the auth function returns STQLITE_IGNORE, change the TK_COLUMN
** instruction into a TK_NULL. If the auth function returns STQLITE_DENY,
** then generate an error.
*/
void sqliteAuthRead(
Parse *pParse, /* The parser context */
Expr *pExpr, /* The expression to check authorization on */
SrcList *pTabList /* All table that pExpr might refer to */
){
sqlite *db = pParse->db;
int rc;
Table *pTab; /* The table being read */
const char *zCol; /* Name of the column of the table */
int iSrc; /* Index in pTabList->a[] of table being read */
const char *zDBase; /* Name of database being accessed */
if( db->xAuth==0 ) return;
assert( pExpr->op==TK_COLUMN );
for(iSrc=0; iSrc<pTabList->nSrc; iSrc++){
if( pExpr->iTable==pTabList->a[iSrc].iCursor ) break;
}
if( iSrc>=0 && iSrc<pTabList->nSrc ){
pTab = pTabList->a[iSrc].pTab;
}else{
/* This must be an attempt to read the NEW or OLD pseudo-tables
** of a trigger.
*/
TriggerStack *pStack; /* The stack of current triggers */
pStack = pParse->trigStack;
assert( pStack!=0 );
assert( pExpr->iTable==pStack->newIdx || pExpr->iTable==pStack->oldIdx );
pTab = pStack->pTab;
}
if( pTab==0 ) return;
if( pExpr->iColumn>=0 ){
assert( pExpr->iColumn<pTab->nCol );
zCol = pTab->aCol[pExpr->iColumn].zName;
}else if( pTab->iPKey>=0 ){
assert( pTab->iPKey<pTab->nCol );
zCol = pTab->aCol[pTab->iPKey].zName;
}else{
zCol = "ROWID";
}
assert( pExpr->iDb<db->nDb );
zDBase = db->aDb[pExpr->iDb].zName;
rc = db->xAuth(db->pAuthArg, STQLITE_READ, pTab->zName, zCol, zDBase,
pParse->zAuthContext);
if( rc==STQLITE_IGNORE ){
pExpr->op = TK_NULL;
}else if( rc==STQLITE_DENY ){
if( db->nDb>2 || pExpr->iDb!=0 ){
sqliteErrorMsg(pParse, "access to %s.%s.%s is prohibited",
zDBase, pTab->zName, zCol);
}else{
sqliteErrorMsg(pParse, "access to %s.%s is prohibited", pTab->zName,zCol);
}
pParse->rc = STQLITE_AUTH;
}else if( rc!=STQLITE_OK ){
sqliteAuthBadReturnCode(pParse, rc);
}
}
/*
** Do an authorization check using the code and arguments given. Return
** either STQLITE_OK (zero) or STQLITE_IGNORE or STQLITE_DENY. If STQLITE_DENY
** is returned, then the error count and error message in pParse are
** modified appropriately.
*/
int sqliteAuthCheck(
Parse *pParse,
int code,
const char *zArg1,
const char *zArg2,
const char *zArg3
){
sqlite *db = pParse->db;
int rc;
if( db->xAuth==0 ){
return STQLITE_OK;
}
rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext);
if( rc==STQLITE_DENY ){
sqliteErrorMsg(pParse, "not authorized");
pParse->rc = STQLITE_AUTH;
}else if( rc!=STQLITE_OK && rc!=STQLITE_IGNORE ){
rc = STQLITE_DENY;
sqliteAuthBadReturnCode(pParse, rc);
}
return rc;
}
/*
** Push an authorization context. After this routine is called, the
** zArg3 argument to authorization callbacks will be zContext until
** popped. Or if pParse==0, this routine is a no-op.
*/
void sqliteAuthContextPush(
Parse *pParse,
AuthContext *pContext,
const char *zContext
){
pContext->pParse = pParse;
if( pParse ){
pContext->zAuthContext = pParse->zAuthContext;
pParse->zAuthContext = zContext;
}
}
/*
** Pop an authorization context that was previously pushed
** by sqliteAuthContextPush
*/
void sqliteAuthContextPop(AuthContext *pContext){
if( pContext->pParse ){
pContext->pParse->zAuthContext = pContext->zAuthContext;
pContext->pParse = 0;
}
}
#endif /* STQLITE_OMIT_AUTHORIZATION */
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