356 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			356 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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| ** 2014-09-08
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| **
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| ** The author disclaims copyright to this source code.  In place of
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| ** a legal notice, here is a blessing:
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| **
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| **    May you do good and not evil.
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| **    May you find forgiveness for yourself and forgive others.
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| **    May you share freely, never taking more than you give.
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| **
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| *************************************************************************
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| **
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| ** This file contains the bulk of the implementation of the
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| ** user-authentication extension feature.  Some parts of the user-
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| ** authentication code are contained within the SQLite core (in the
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| ** src/ subdirectory of the main source code tree) but those parts
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| ** that could reasonable be separated out are moved into this file.
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| **
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| ** To compile with the user-authentication feature, append this file to
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| ** end of an SQLite amalgamation, then add the SQLITE_USER_AUTHENTICATION
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| ** compile-time option.  See the user-auth.txt file in the same source
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| ** directory as this file for additional information.
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| */
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| #ifdef SQLITE_USER_AUTHENTICATION
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| #ifndef _SQLITEINT_H_
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| # include "sqliteInt.h"
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| #endif
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| 
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| /*
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| ** Prepare an SQL statement for use by the user authentication logic.
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| ** Return a pointer to the prepared statement on success.  Return a
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| ** NULL pointer if there is an error of any kind.
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| */
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| static sqlite3_stmt *sqlite3UserAuthPrepare(
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|   sqlite3 *db,
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|   const char *zFormat,
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|   ...
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| ){
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|   sqlite3_stmt *pStmt;
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|   char *zSql;
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|   int rc;
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|   va_list ap;
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|   int savedFlags = db->flags;
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| 
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|   va_start(ap, zFormat);
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|   zSql = sqlite3_vmprintf(zFormat, ap);
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|   va_end(ap);
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|   if( zSql==0 ) return 0;
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|   db->flags |= SQLITE_WriteSchema;
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|   rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
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|   db->flags = savedFlags;
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|   sqlite3_free(zSql);
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|   if( rc ){
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|     sqlite3_finalize(pStmt);
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|     pStmt = 0;
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|   }
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|   return pStmt;
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| }
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| 
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| /*
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| ** Check to see if the sqlite_user table exists in database zDb.
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| */
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| static int userTableExists(sqlite3 *db, const char *zDb){
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|   int rc;
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|   sqlite3_mutex_enter(db->mutex);
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|   sqlite3BtreeEnterAll(db);
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|   if( db->init.busy==0 ){
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|     char *zErr = 0;
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|     sqlite3Init(db, &zErr);
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|     sqlite3DbFree(db, zErr);
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|   }
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|   rc = sqlite3FindTable(db, "sqlite_user", zDb)!=0;
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|   sqlite3BtreeLeaveAll(db);
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|   sqlite3_mutex_leave(db->mutex);
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|   return rc;
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| }
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| 
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| /*
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| ** Check to see if database zDb has a "sqlite_user" table and if it does
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| ** whether that table can authenticate zUser with nPw,zPw.  Write one of
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| ** the UAUTH_* user authorization level codes into *peAuth and return a
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| ** result code.
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| */
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| static int userAuthCheckLogin(
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|   sqlite3 *db,               /* The database connection to check */
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|   const char *zDb,           /* Name of specific database to check */
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|   u8 *peAuth                 /* OUT: One of UAUTH_* constants */
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| ){
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|   sqlite3_stmt *pStmt;
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|   int rc;
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| 
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|   *peAuth = UAUTH_Unknown;
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|   if( !userTableExists(db, "main") ){
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|     *peAuth = UAUTH_Admin;  /* No sqlite_user table.  Everybody is admin. */
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|     return SQLITE_OK;
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|   }
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|   if( db->auth.zAuthUser==0 ){
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|     *peAuth = UAUTH_Fail;
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|     return SQLITE_OK;
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|   }
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|   pStmt = sqlite3UserAuthPrepare(db,
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|             "SELECT pw=sqlite_crypt(?1,pw), isAdmin FROM \"%w\".sqlite_user"
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|             " WHERE uname=?2", zDb);
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|   if( pStmt==0 ) return SQLITE_NOMEM;
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|   sqlite3_bind_blob(pStmt, 1, db->auth.zAuthPW, db->auth.nAuthPW,SQLITE_STATIC);
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|   sqlite3_bind_text(pStmt, 2, db->auth.zAuthUser, -1, SQLITE_STATIC);
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|   rc = sqlite3_step(pStmt);
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|   if( rc==SQLITE_ROW && sqlite3_column_int(pStmt,0) ){
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|     *peAuth = sqlite3_column_int(pStmt, 1) + UAUTH_User;
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|   }else{
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|     *peAuth = UAUTH_Fail;
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|   }
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|   return sqlite3_finalize(pStmt);
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| }
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| int sqlite3UserAuthCheckLogin(
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|   sqlite3 *db,               /* The database connection to check */
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|   const char *zDb,           /* Name of specific database to check */
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|   u8 *peAuth                 /* OUT: One of UAUTH_* constants */
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| ){
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|   int rc;
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|   u8 savedAuthLevel;
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|   assert( zDb!=0 );
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|   assert( peAuth!=0 );
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|   savedAuthLevel = db->auth.authLevel;
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|   db->auth.authLevel = UAUTH_Admin;
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|   rc = userAuthCheckLogin(db, zDb, peAuth);
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|   db->auth.authLevel = savedAuthLevel;
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|   return rc;
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| }
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| 
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| /*
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| ** If the current authLevel is UAUTH_Unknown, the take actions to figure
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| ** out what authLevel should be
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| */
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| void sqlite3UserAuthInit(sqlite3 *db){
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|   if( db->auth.authLevel==UAUTH_Unknown ){
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|     u8 authLevel = UAUTH_Fail;
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|     sqlite3UserAuthCheckLogin(db, "main", &authLevel);
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|     db->auth.authLevel = authLevel;
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|     if( authLevel<UAUTH_Admin ) db->flags &= ~SQLITE_WriteSchema;
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|   }
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| }
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| 
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| /*
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| ** Implementation of the sqlite_crypt(X,Y) function.
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| **
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| ** If Y is NULL then generate a new hash for password X and return that
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| ** hash.  If Y is not null, then generate a hash for password X using the
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| ** same salt as the previous hash Y and return the new hash.
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| */
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| void sqlite3CryptFunc(
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|   sqlite3_context *context,
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|   int NotUsed,
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|   sqlite3_value **argv
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| ){
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|   const char *zIn;
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|   int nIn, ii;
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|   u8 *zOut;
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|   char zSalt[8];
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|   zIn = sqlite3_value_blob(argv[0]);
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|   nIn = sqlite3_value_bytes(argv[0]);
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|   if( sqlite3_value_type(argv[1])==SQLITE_BLOB
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|    && sqlite3_value_bytes(argv[1])==nIn+sizeof(zSalt)
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|   ){
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|     memcpy(zSalt, sqlite3_value_blob(argv[1]), sizeof(zSalt));
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|   }else{
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|     sqlite3_randomness(sizeof(zSalt), zSalt);
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|   }
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|   zOut = sqlite3_malloc( nIn+sizeof(zSalt) );
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|   if( zOut==0 ){
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|     sqlite3_result_error_nomem(context);
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|   }else{
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|     memcpy(zOut, zSalt, sizeof(zSalt));
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|     for(ii=0; ii<nIn; ii++){
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|       zOut[ii+sizeof(zSalt)] = zIn[ii]^zSalt[ii&0x7];
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|     }
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|     sqlite3_result_blob(context, zOut, nIn+sizeof(zSalt), sqlite3_free);
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|   }
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| }
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| 
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| /*
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| ** If a database contains the SQLITE_USER table, then the
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| ** sqlite3_user_authenticate() interface must be invoked with an
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| ** appropriate username and password prior to enable read and write
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| ** access to the database.
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| **
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| ** Return SQLITE_OK on success or SQLITE_ERROR if the username/password
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| ** combination is incorrect or unknown.
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| **
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| ** If the SQLITE_USER table is not present in the database file, then
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| ** this interface is a harmless no-op returnning SQLITE_OK.
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| */
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| int sqlite3_user_authenticate(
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|   sqlite3 *db,           /* The database connection */
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|   const char *zUsername, /* Username */
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|   const char *zPW,       /* Password or credentials */
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|   int nPW                /* Number of bytes in aPW[] */
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| ){
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|   int rc;
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|   u8 authLevel = UAUTH_Fail;
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|   db->auth.authLevel = UAUTH_Unknown;
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|   sqlite3_free(db->auth.zAuthUser);
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|   sqlite3_free(db->auth.zAuthPW);
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|   memset(&db->auth, 0, sizeof(db->auth));
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|   db->auth.zAuthUser = sqlite3_mprintf("%s", zUsername);
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|   if( db->auth.zAuthUser==0 ) return SQLITE_NOMEM;
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|   db->auth.zAuthPW = sqlite3_malloc( nPW+1 );
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|   if( db->auth.zAuthPW==0 ) return SQLITE_NOMEM;
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|   memcpy(db->auth.zAuthPW,zPW,nPW);
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|   db->auth.nAuthPW = nPW;
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|   rc = sqlite3UserAuthCheckLogin(db, "main", &authLevel);
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|   db->auth.authLevel = authLevel;
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|   sqlite3ExpirePreparedStatements(db);
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|   if( rc ){
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|     return rc;           /* OOM error, I/O error, etc. */
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|   }
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|   if( authLevel<UAUTH_User ){
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|     return SQLITE_AUTH;  /* Incorrect username and/or password */
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|   }
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|   return SQLITE_OK;      /* Successful login */
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| }
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| 
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| /*
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| ** The sqlite3_user_add() interface can be used (by an admin user only)
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| ** to create a new user.  When called on a no-authentication-required
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| ** database, this routine converts the database into an authentication-
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| ** required database, automatically makes the added user an
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| ** administrator, and logs in the current connection as that user.
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| ** The sqlite3_user_add() interface only works for the "main" database, not
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| ** for any ATTACH-ed databases.  Any call to sqlite3_user_add() by a
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| ** non-admin user results in an error.
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| */
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| int sqlite3_user_add(
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|   sqlite3 *db,           /* Database connection */
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|   const char *zUsername, /* Username to be added */
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|   const char *aPW,       /* Password or credentials */
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|   int nPW,               /* Number of bytes in aPW[] */
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|   int isAdmin            /* True to give new user admin privilege */
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| ){
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|   sqlite3_stmt *pStmt;
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|   int rc;
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|   sqlite3UserAuthInit(db);
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|   if( db->auth.authLevel<UAUTH_Admin ) return SQLITE_AUTH;
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|   if( !userTableExists(db, "main") ){
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|     if( !isAdmin ) return SQLITE_AUTH;
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|     pStmt = sqlite3UserAuthPrepare(db, 
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|               "CREATE TABLE sqlite_user(\n"
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|               "  uname TEXT PRIMARY KEY,\n"
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|               "  isAdmin BOOLEAN,\n"
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|               "  pw BLOB\n"
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|               ") WITHOUT ROWID;");
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|     if( pStmt==0 ) return SQLITE_NOMEM;
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|     sqlite3_step(pStmt);
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|     rc = sqlite3_finalize(pStmt);
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|     if( rc ) return rc;
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|   }
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|   pStmt = sqlite3UserAuthPrepare(db, 
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|             "INSERT INTO sqlite_user(uname,isAdmin,pw)"
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|             " VALUES(%Q,%d,sqlite_crypt(?1,NULL))",
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|             zUsername, isAdmin!=0);
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|   if( pStmt==0 ) return SQLITE_NOMEM;
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|   sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
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|   sqlite3_step(pStmt);
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|   rc = sqlite3_finalize(pStmt);
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|   if( rc ) return rc;
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|   if( db->auth.zAuthUser==0 ){
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|     assert( isAdmin!=0 );
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|     sqlite3_user_authenticate(db, zUsername, aPW, nPW);
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|   }
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|   return SQLITE_OK;
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| }
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| 
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| /*
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| ** The sqlite3_user_change() interface can be used to change a users
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| ** login credentials or admin privilege.  Any user can change their own
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| ** login credentials.  Only an admin user can change another users login
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| ** credentials or admin privilege setting.  No user may change their own 
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| ** admin privilege setting.
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| */
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| int sqlite3_user_change(
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|   sqlite3 *db,           /* Database connection */
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|   const char *zUsername, /* Username to change */
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|   const char *aPW,       /* Modified password or credentials */
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|   int nPW,               /* Number of bytes in aPW[] */
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|   int isAdmin            /* Modified admin privilege for the user */
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| ){
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|   sqlite3_stmt *pStmt;
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|   int rc;
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|   u8 authLevel;
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| 
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|   authLevel = db->auth.authLevel;
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|   if( authLevel<UAUTH_User ){
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|     /* Must be logged in to make a change */
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|     return SQLITE_AUTH;
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|   }
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|   if( strcmp(db->auth.zAuthUser, zUsername)!=0 ){
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|     if( db->auth.authLevel<UAUTH_Admin ){
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|       /* Must be an administrator to change a different user */
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|       return SQLITE_AUTH;
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|     }
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|   }else if( isAdmin!=(authLevel==UAUTH_Admin) ){
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|     /* Cannot change the isAdmin setting for self */
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|     return SQLITE_AUTH;
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|   }
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|   db->auth.authLevel = UAUTH_Admin;
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|   if( !userTableExists(db, "main") ){
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|     /* This routine is a no-op if the user to be modified does not exist */
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|   }else{
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|     pStmt = sqlite3UserAuthPrepare(db,
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|               "UPDATE sqlite_user SET isAdmin=%d, pw=sqlite_crypt(?1,NULL)"
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|               " WHERE uname=%Q", isAdmin, zUsername);
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|     if( pStmt==0 ){
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|       rc = SQLITE_NOMEM;
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|     }else{
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|       sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
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|       sqlite3_step(pStmt);
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|       rc = sqlite3_finalize(pStmt);
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|     }
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|   }
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|   db->auth.authLevel = authLevel;
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|   return rc;
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| }
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| 
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| /*
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| ** The sqlite3_user_delete() interface can be used (by an admin user only)
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| ** to delete a user.  The currently logged-in user cannot be deleted,
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| ** which guarantees that there is always an admin user and hence that
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| ** the database cannot be converted into a no-authentication-required
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| ** database.
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| */
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| int sqlite3_user_delete(
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|   sqlite3 *db,           /* Database connection */
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|   const char *zUsername  /* Username to remove */
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| ){
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|   sqlite3_stmt *pStmt;
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|   if( db->auth.authLevel<UAUTH_Admin ){
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|     /* Must be an administrator to delete a user */
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|     return SQLITE_AUTH;
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|   }
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|   if( strcmp(db->auth.zAuthUser, zUsername)==0 ){
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|     /* Cannot delete self */
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|     return SQLITE_AUTH;
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|   }
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|   if( !userTableExists(db, "main") ){
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|     /* This routine is a no-op if the user to be deleted does not exist */
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|     return SQLITE_OK;
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|   }
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|   pStmt = sqlite3UserAuthPrepare(db,
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|               "DELETE FROM sqlite_user WHERE uname=%Q", zUsername);
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|   if( pStmt==0 ) return SQLITE_NOMEM;
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|   sqlite3_step(pStmt);
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|   return sqlite3_finalize(pStmt);
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| }
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| 
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| #endif /* SQLITE_USER_AUTHENTICATION */
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