sqlite/ext/userauth/userauth.c
drh e933b83f02 Further ideas on user authentication. Not yet working code.
FossilOrigin-Name: c8171ecd0d6f097c9e95d5f6643bae8d67f44750
2014-09-10 17:34:28 +00:00

217 lines
7.3 KiB
C

/*
** 2014-09-08
**
** 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 the bulk of the implementation of the
** user-authentication extension feature. Some parts of the user-
** authentication code are contained within the SQLite core (in the
** src/ subdirectory of the main source code tree) but those parts
** that could reasonable be separated out are moved into this file.
**
** To compile with the user-authentication feature, append this file to
** end of an SQLite amalgamation, then add the SQLITE_USER_AUTHENTICATION
** compile-time option. See the user-auth.txt file in the same source
** directory as this file for additional information.
*/
#ifdef SQLITE_USER_AUTHENTICATION
#include "sqliteInt.h"
/*
** Prepare an SQL statement for use by the user authentication logic.
** Return a pointer to the prepared statement on success. Return a
** NULL pointer if there is an error of any kind.
*/
static sqlite3_stmt *sqlite3UserAuthPrepare(
sqlite3 *db,
const char *zFormat,
...
){
sqlite3_stmt *pStmt;
char *zSql;
int rc;
va_list ap;
va_start(ap, zFormat);
zSql = sqlite3_vmprintf(zFormat, ap);
va_end(ap);
if( zSql==0 ) return 0;
rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
sqlite3_free(zSql);
if( rc ){
sqlite3_finalize(pStmt);
pStmt = 0;
}
return pStmt;
}
/*
** Check to see if database zDb has a "sqlite_user" table and if it does
** whether that table can authenticate zUser with nPw,zPw. Write one of
** the UAUTH_* user authorization level codes into *peAuth and return a
** result code.
*/
static int userAuthCheckLogin(
sqlite3 *db, /* The database connection to check */
const char *zDb, /* Name of specific database to check */
u8 *peAuth /* OUT: One of UAUTH_* constants */
){
sqlite3_stmt *pStmt;
int rc;
*peAuth = UAUTH_Unknown;
pStmt = sqlite3UserAuthPrepare(db,
"SELECT 1 FROM \"%w\".sqlite_master "
" WHERE name='sqlite_user' AND type='table'", zDb);
if( pStmt==0 ){
return SQLITE_NOMEM;
}
rc = sqlite3_step(pStmt);
sqlite3_finalize(pStmt);
if( rc==SQLITE_DONE ){
*peAuth = UAUTH_Admin; /* No sqlite_user table. Everybody is admin. */
return SQLITE_OK;
}
if( rc!=SQLITE_ROW ){
return rc;
}
if( db->auth.zAuthUser==0 ){
*peAuth = UAUTH_Fail;
return SQLITE_OK;
}
pStmt = sqlite3UserAuthPrepare(db,
"SELECT pw=sqlite_crypt(?1,pw), isAdmin FROM \"%w\".sqlite_user"
" WHERE uname=?2", zDb);
if( pStmt==0 ) return SQLITE_NOMEM;
sqlite3_bind_blob(pStmt, 1, db->auth.zAuthPW, db->auth.nAuthPW,SQLITE_STATIC);
sqlite3_bind_text(pStmt, 2, db->auth.zAuthUser, -1, SQLITE_STATIC);
rc = sqlite3_step(pStmt);
if( rc==SQLITE_ROW && sqlite3_column_int(pStmt,0) ){
*peAuth = sqlite3_column_int(pStmt, 1) + UAUTH_User;
}else{
*peAuth = UAUTH_Fail;
}
sqlite3_finalize(pStmt);
return rc;
}
int sqlite3UserAuthCheckLogin(
sqlite3 *db, /* The database connection to check */
const char *zDb, /* Name of specific database to check */
u8 *peAuth /* OUT: One of UAUTH_* constants */
){
int rc;
u8 savedAuthLevel;
savedAuthLevel = db->auth.authLevel;
db->auth.authLevel = UAUTH_Admin;
rc = userAuthCheckLogin(db, zDb, peAuth);
db->auth.authLevel = savedAuthLevel;
return rc;
}
/*
** If a database contains the SQLITE_USER table, then the
** sqlite3_user_authenticate() interface must be invoked with an
** appropriate username and password prior to enable read and write
** access to the database.
**
** Return SQLITE_OK on success or SQLITE_ERROR if the username/password
** combination is incorrect or unknown.
**
** If the SQLITE_USER table is not present in the database file, then
** this interface is a harmless no-op returnning SQLITE_OK.
*/
int sqlite3_user_authenticate(
sqlite3 *db, /* The database connection */
const char *zUsername, /* Username */
int nPW, /* Number of bytes in aPW[] */
const char *zPW /* Password or credentials */
){
int rc;
u8 authLevel = UAUTH_Fail;
db->auth.authLevel = UAUTH_Unknown;
sqlite3_free(db->auth.zAuthUser);
sqlite3_free(db->auth.zAuthPW);
memset(&db->auth, 0, sizeof(db->auth));
db->auth.zAuthUser = sqlite3_mprintf("%s", zUsername);
if( db->auth.zAuthUser==0 ) return SQLITE_NOMEM;
db->auth.zAuthPW = sqlite3_malloc( nPW+1 );
if( db->auth.zAuthPW==0 ) return SQLITE_NOMEM;
memcpy(db->auth.zAuthPW,zPW,nPW);
db->auth.nAuthPW = nPW;
rc = sqlite3UserAuthCheckLogin(db, "main", &authLevel);
db->auth.authLevel = authLevel;
if( rc ){
return rc; /* OOM error, I/O error, etc. */
}
if( authLevel<UAUTH_User ){
return SQLITE_AUTH; /* Incorrect username and/or password */
}
return SQLITE_OK; /* Successful login */
}
/*
** The sqlite3_user_add() interface can be used (by an admin user only)
** to create a new user. When called on a no-authentication-required
** database, this routine converts the database into an authentication-
** required database, automatically makes the added user an
** administrator, and logs in the current connection as that user.
** The sqlite3_user_add() interface only works for the "main" database, not
** for any ATTACH-ed databases. Any call to sqlite3_user_add() by a
** non-admin user results in an error.
*/
int sqlite3_user_add(
sqlite3 *db, /* Database connection */
const char *zUsername, /* Username to be added */
int isAdmin, /* True to give new user admin privilege */
int nPW, /* Number of bytes in aPW[] */
const void *aPW /* Password or credentials */
){
if( db->auth.authLevel<UAUTH_Admin ) return SQLITE_ERROR;
return SQLITE_OK;
}
/*
** The sqlite3_user_change() interface can be used to change a users
** login credentials or admin privilege. Any user can change their own
** login credentials. Only an admin user can change another users login
** credentials or admin privilege setting. No user may change their own
** admin privilege setting.
*/
int sqlite3_user_change(
sqlite3 *db, /* Database connection */
const char *zUsername, /* Username to change */
int isAdmin, /* Modified admin privilege for the user */
int nPW, /* Number of bytes in aPW[] */
const void *aPW /* Modified password or credentials */
){
if( db->auth.authLevel<UAUTH_User ) return SQLITE_ERROR;
if( strcmp(db->auth.zAuthUser, zUsername)!=0
&& db->auth.authLevel<UAUTH_Admin ) return SQLITE_ERROR;
return SQLITE_OK;
}
/*
** The sqlite3_user_delete() interface can be used (by an admin user only)
** to delete a user. The currently logged-in user cannot be deleted,
** which guarantees that there is always an admin user and hence that
** the database cannot be converted into a no-authentication-required
** database.
*/
int sqlite3_user_delete(
sqlite3 *db, /* Database connection */
const char *zUsername /* Username to remove */
){
if( db->auth.authLevel<UAUTH_Admin ) return SQLITE_ERROR;
return SQLITE_OK;
}
#endif /* SQLITE_USER_AUTHENTICATION */