/*
** 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
#ifndef SQLITEINT_H
# include "sqliteInt.h"
#endif
/*
** 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;
int savedFlags = db->flags;
va_start(ap, zFormat);
zSql = sqlite3_vmprintf(zFormat, ap);
va_end(ap);
if( zSql==0 ) return 0;
db->flags |= SQLITE_WriteSchema;
rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
db->flags = savedFlags;
sqlite3_free(zSql);
if( rc ){
sqlite3_finalize(pStmt);
pStmt = 0;
}
return pStmt;
}
/*
** Check to see if the sqlite_user table exists in database zDb.
*/
static int userTableExists(sqlite3 *db, const char *zDb){
int rc;
sqlite3_mutex_enter(db->mutex);
sqlite3BtreeEnterAll(db);
if( db->init.busy==0 ){
char *zErr = 0;
sqlite3Init(db, &zErr);
sqlite3DbFree(db, zErr);
}
rc = sqlite3FindTable(db, "sqlite_user", zDb)!=0;
sqlite3BtreeLeaveAll(db);
sqlite3_mutex_leave(db->mutex);
return rc;
}
/*
** 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;
if( !userTableExists(db, "main") ){
*peAuth = UAUTH_Admin; /* No sqlite_user table. Everybody is admin. */
return SQLITE_OK;
}
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;
}
return sqlite3_finalize(pStmt);
}
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;
assert( zDb!=0 );
assert( peAuth!=0 );
savedAuthLevel = db->auth.authLevel;
db->auth.authLevel = UAUTH_Admin;
rc = userAuthCheckLogin(db, zDb, peAuth);
db->auth.authLevel = savedAuthLevel;
return rc;
}
/*
** If the current authLevel is UAUTH_Unknown, the take actions to figure
** out what authLevel should be
*/
void sqlite3UserAuthInit(sqlite3 *db){
if( db->auth.authLevel==UAUTH_Unknown ){
u8 authLevel = UAUTH_Fail;
sqlite3UserAuthCheckLogin(db, "main", &authLevel);
db->auth.authLevel = authLevel;
if( authLevel<UAUTH_Admin ) db->flags &= ~SQLITE_WriteSchema;
}
}
/*
** Implementation of the sqlite_crypt(X,Y) function.
**
** If Y is NULL then generate a new hash for password X and return that
** hash. If Y is not null, then generate a hash for password X using the
** same salt as the previous hash Y and return the new hash.
*/
void sqlite3CryptFunc(
sqlite3_context *context,
int NotUsed,
sqlite3_value **argv
){
const char *zIn;
int nIn, ii;
u8 *zOut;
char zSalt[8];
zIn = sqlite3_value_blob(argv[0]);
nIn = sqlite3_value_bytes(argv[0]);
if( sqlite3_value_type(argv[1])==SQLITE_BLOB
&& sqlite3_value_bytes(argv[1])==nIn+sizeof(zSalt)
){
memcpy(zSalt, sqlite3_value_blob(argv[1]), sizeof(zSalt));
}else{
sqlite3_randomness(sizeof(zSalt), zSalt);
}
zOut = sqlite3_malloc( nIn+sizeof(zSalt) );
if( zOut==0 ){
sqlite3_result_error_nomem(context);
}else{
memcpy(zOut, zSalt, sizeof(zSalt));
for(ii=0; ii<nIn; ii++){
zOut[ii+sizeof(zSalt)] = zIn[ii]^zSalt[ii&0x7];
}
sqlite3_result_blob(context, zOut, nIn+sizeof(zSalt), sqlite3_free);
}
}
/*
** 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 */
const char *zPW, /* Password or credentials */
int nPW /* Number of bytes in aPW[] */
){
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;
sqlite3ExpirePreparedStatements(db, 0);
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 */
const char *aPW, /* Password or credentials */
int nPW, /* Number of bytes in aPW[] */
int isAdmin /* True to give new user admin privilege */
){
sqlite3_stmt *pStmt;
int rc;
sqlite3UserAuthInit(db);
if( db->auth.authLevel<UAUTH_Admin ) return SQLITE_AUTH;
if( !userTableExists(db, "main") ){
if( !isAdmin ) return SQLITE_AUTH;
pStmt = sqlite3UserAuthPrepare(db,
"CREATE TABLE sqlite_user(\n"
" uname TEXT PRIMARY KEY,\n"
" isAdmin BOOLEAN,\n"
" pw BLOB\n"
") WITHOUT ROWID;");
if( pStmt==0 ) return SQLITE_NOMEM;
sqlite3_step(pStmt);
rc = sqlite3_finalize(pStmt);
if( rc ) return rc;
}
pStmt = sqlite3UserAuthPrepare(db,
"INSERT INTO sqlite_user(uname,isAdmin,pw)"
" VALUES(%Q,%d,sqlite_crypt(?1,NULL))",
zUsername, isAdmin!=0);
if( pStmt==0 ) return SQLITE_NOMEM;
sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
sqlite3_step(pStmt);
rc = sqlite3_finalize(pStmt);
if( rc ) return rc;
if( db->auth.zAuthUser==0 ){
assert( isAdmin!=0 );
sqlite3_user_authenticate(db, zUsername, aPW, nPW);
}
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 */
const char *aPW, /* Modified password or credentials */
int nPW, /* Number of bytes in aPW[] */
int isAdmin /* Modified admin privilege for the user */
){
sqlite3_stmt *pStmt;
int rc;
u8 authLevel;
authLevel = db->auth.authLevel;
if( authLevel<UAUTH_User ){
/* Must be logged in to make a change */
return SQLITE_AUTH;
}
if( strcmp(db->auth.zAuthUser, zUsername)!=0 ){
if( db->auth.authLevel<UAUTH_Admin ){
/* Must be an administrator to change a different user */
return SQLITE_AUTH;
}
}else if( isAdmin!=(authLevel==UAUTH_Admin) ){
/* Cannot change the isAdmin setting for self */
return SQLITE_AUTH;
}
db->auth.authLevel = UAUTH_Admin;
if( !userTableExists(db, "main") ){
/* This routine is a no-op if the user to be modified does not exist */
}else{
pStmt = sqlite3UserAuthPrepare(db,
"UPDATE sqlite_user SET isAdmin=%d, pw=sqlite_crypt(?1,NULL)"
" WHERE uname=%Q", isAdmin, zUsername);
if( pStmt==0 ){
rc = SQLITE_NOMEM;
}else{
sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
sqlite3_step(pStmt);
rc = sqlite3_finalize(pStmt);
}
}
db->auth.authLevel = authLevel;
return rc;
}
/*
** 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 */
){
sqlite3_stmt *pStmt;
if( db->auth.authLevel<UAUTH_Admin ){
/* Must be an administrator to delete a user */
return SQLITE_AUTH;
}
if( strcmp(db->auth.zAuthUser, zUsername)==0 ){
/* Cannot delete self */
return SQLITE_AUTH;
}
if( !userTableExists(db, "main") ){
/* This routine is a no-op if the user to be deleted does not exist */
return SQLITE_OK;
}
pStmt = sqlite3UserAuthPrepare(db,
"DELETE FROM sqlite_user WHERE uname=%Q", zUsername);
if( pStmt==0 ) return SQLITE_NOMEM;
sqlite3_step(pStmt);
return sqlite3_finalize(pStmt);
}
#endif /* SQLITE_USER_AUTHENTICATION */