/*** 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 find forgiveness for yourself and forgive others.**    May you share freely, never taking more than you give.***************************************************************************** This file contains 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 -DSQLITE_OMIT_AUTHORIZATION=1**** $Id: qt/auth.c   3.3.4   edited Mar 30 2004 $*/#include "sqliteInt.h"/*** All of the code in this file may be omitted by defining a single** macro.*/#ifndef SQLITE_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:****       SQLITE_COPY**       SQLITE_CREATE_INDEX**       SQLITE_CREATE_TABLE**       SQLITE_CREATE_TEMP_INDEX**       SQLITE_CREATE_TEMP_TABLE**       SQLITE_CREATE_TEMP_TRIGGER**       SQLITE_CREATE_TEMP_VIEW**       SQLITE_CREATE_TRIGGER**       SQLITE_CREATE_VIEW**       SQLITE_DELETE**       SQLITE_DROP_INDEX**       SQLITE_DROP_TABLE**       SQLITE_DROP_TEMP_INDEX**       SQLITE_DROP_TEMP_TABLE**       SQLITE_DROP_TEMP_TRIGGER**       SQLITE_DROP_TEMP_VIEW**       SQLITE_DROP_TRIGGER**       SQLITE_DROP_VIEW**       SQLITE_INSERT**       SQLITE_PRAGMA**       SQLITE_READ**       SQLITE_SELECT**       SQLITE_TRANSACTION**       SQLITE_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 SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE.  If** SQLITE_OK is returned, it means that access is allowed.  SQLITE_DENY** means that the SQL statement will never-run - the sqlite_exec() call** will return with an error.  SQLITE_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 SQLITE_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 SQLITE_OK, SQLITE_IGNORE, "    "or SQLITE_DENY", rc);  pParse->rc = SQLITE_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 SQLITE_IGNORE, change the TK_COLUMN ** instruction into a TK_NULL.  If the auth function returns SQLITE_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, SQLITE_READ, pTab->zName, zCol, zDBase,                  pParse->zAuthContext);  if( rc==SQLITE_IGNORE ){    pExpr->op = TK_NULL;  }else if( rc==SQLITE_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 = SQLITE_AUTH;  }else if( rc!=SQLITE_OK ){    sqliteAuthBadReturnCode(pParse, rc);  }}/*** Do an authorization check using the code and arguments given.  Return** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY.  If SQLITE_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 SQLITE_OK;  }  rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext);  if( rc==SQLITE_DENY ){    sqliteErrorMsg(pParse, "not authorized");    pParse->rc = SQLITE_AUTH;  }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){    rc = SQLITE_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 /* SQLITE_OMIT_AUTHORIZATION */