mirror of
https://github.com/tursodatabase/libsql.git
synced 2024-12-15 21:29:01 +00:00
165 lines
6.9 KiB
Plaintext
165 lines
6.9 KiB
Plaintext
Activate the user authentication logic by including the
|
|
ext/userauth/userauth.c source code file in the build and
|
|
adding the -DSQLITE_USER_AUTHENTICATION compile-time option.
|
|
The ext/userauth/sqlite3userauth.h header file is available to
|
|
applications to define the interface.
|
|
|
|
When using the SQLite amalgamation, it is sufficient to append
|
|
the ext/userauth/userauth.c source file onto the end of the
|
|
amalgamation.
|
|
|
|
The following new APIs are available when user authentication is
|
|
activated:
|
|
|
|
int sqlite3_user_authenticate(
|
|
sqlite3 *db, /* The database connection */
|
|
const char *zUsername, /* Username */
|
|
const char *aPW, /* Password or credentials */
|
|
int nPW /* Number of bytes in aPW[] */
|
|
);
|
|
|
|
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 */
|
|
);
|
|
|
|
int sqlite3_user_change(
|
|
sqlite3 *db, /* Database connection */
|
|
const char *zUsername, /* Username to change */
|
|
const void *aPW, /* Modified password or credentials */
|
|
int nPW, /* Number of bytes in aPW[] */
|
|
int isAdmin /* Modified admin privilege for the user */
|
|
);
|
|
|
|
int sqlite3_user_delete(
|
|
sqlite3 *db, /* Database connection */
|
|
const char *zUsername /* Username to remove */
|
|
);
|
|
|
|
With this extension, a database can be marked as requiring authentication.
|
|
By default a database does not require authentication.
|
|
|
|
The sqlite3_open(), sqlite3_open16(), and sqlite3_open_v2() interfaces
|
|
work as before: they open a new database connection. However, if the
|
|
database being opened requires authentication, then attempts to read
|
|
or write from the database will fail with an SQLITE_AUTH error until
|
|
after sqlite3_user_authenticate() has been called successfully. The
|
|
sqlite3_user_authenticate() call will return SQLITE_OK if the
|
|
authentication credentials are accepted and SQLITE_ERROR if not.
|
|
|
|
Calling sqlite3_user_authenticate() on a no-authentication-required
|
|
database connection is a harmless no-op.
|
|
|
|
If the database is encrypted, then sqlite3_key_v2() must be called first,
|
|
with the correct decryption key, prior to invoking sqlite3_user_authenticate().
|
|
|
|
To recapitulate: When opening an existing unencrypted authentication-
|
|
required database, the call sequence is:
|
|
|
|
sqlite3_open_v2()
|
|
sqlite3_user_authenticate();
|
|
/* Database is now usable */
|
|
|
|
To open an existing, encrypted, authentication-required database, the
|
|
call sequence is:
|
|
|
|
sqlite3_open_v2();
|
|
sqlite3_key_v2();
|
|
sqlite3_user_authenticate();
|
|
/* Database is now usable */
|
|
|
|
When opening a no-authentication-required database, the database
|
|
connection is treated as if it was authenticated as an admin user.
|
|
|
|
When ATTACH-ing new database files to a connection, each newly attached
|
|
database that is an authentication-required database is checked using
|
|
the same username and password as supplied to the main database. If that
|
|
check fails, then the ATTACH command fails with an SQLITE_AUTH error.
|
|
|
|
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 and when A is true, the sqlite3_user_add(D,U,P,N,A) routine
|
|
converts the database into an authentication-required database and
|
|
logs in the database connection D as user U with password P,N.
|
|
To convert a no-authentication-required database into an authentication-
|
|
required database, the isAdmin parameter must be true. If
|
|
sqlite3_user_add(D,U,P,N,A) is called on a no-authentication-required
|
|
database and A is false, then the call fails with an SQLITE_AUTH error.
|
|
|
|
Any call to sqlite3_user_add() by a non-admin user results in an error.
|
|
|
|
Hence, to create a new, unencrypted, authentication-required database,
|
|
the call sequence is:
|
|
|
|
sqlite3_open_v2();
|
|
sqlite3_user_add();
|
|
|
|
And to create a new, encrypted, authentication-required database, the call
|
|
sequence is:
|
|
|
|
sqlite3_open_v2();
|
|
sqlite3_key_v2();
|
|
sqlite3_user_add();
|
|
|
|
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.
|
|
|
|
The sqlite3_user_change() interface can be used to change a users
|
|
login credentials or admin privilege. Any user can change their own
|
|
password. Only an admin user can change another users login
|
|
credentials or admin privilege setting. No user may change their own
|
|
admin privilege setting.
|
|
|
|
The sqlite3_set_authorizer() callback is modified to take a 7th parameter
|
|
which is the username of the currently logged in user, or NULL for a
|
|
no-authentication-required database.
|
|
|
|
-----------------------------------------------------------------------------
|
|
Implementation notes:
|
|
|
|
An authentication-required database is identified by the presence of a
|
|
new table:
|
|
|
|
CREATE TABLE sqlite_user(
|
|
uname TEXT PRIMARY KEY,
|
|
isAdmin BOOLEAN,
|
|
pw BLOB
|
|
) WITHOUT ROWID;
|
|
|
|
The sqlite_user table is inaccessible (unreadable and unwriteable) to
|
|
non-admin users and is read-only for admin users. However, if the same
|
|
database file is opened by a version of SQLite that omits
|
|
the -DSQLITE_USER_AUTHENTICATION compile-time option, then the sqlite_user
|
|
table will be readable by anybody and writeable by anybody if
|
|
the "PRAGMA writable_schema=ON" statement is run first.
|
|
|
|
The sqlite_user.pw field is encoded by a built-in SQL function
|
|
"sqlite_crypt(X,Y)". The two arguments are both BLOBs. The first argument
|
|
is the plaintext password supplied to the sqlite3_user_authenticate()
|
|
interface. The second argument is the sqlite_user.pw value and is supplied
|
|
so that the function can extract the "salt" used by the password encoder.
|
|
The result of sqlite_crypt(X,Y) is another blob which is the value that
|
|
ends up being stored in sqlite_user.pw. To verify credentials X supplied
|
|
by the sqlite3_user_authenticate() routine, SQLite runs:
|
|
|
|
sqlite_user.pw == sqlite_crypt(X, sqlite_user.pw)
|
|
|
|
To compute an appropriate sqlite_user.pw value from a new or modified
|
|
password X, sqlite_crypt(X,NULL) is run. A new random salt is selected
|
|
when the second argument is NULL.
|
|
|
|
The built-in version of of sqlite_crypt() uses a simple Ceasar-cypher
|
|
which prevents passwords from being revealed by searching the raw database
|
|
for ASCII text, but is otherwise trivally broken. For better password
|
|
security, the database should be encrypted using the SQLite Encryption
|
|
Extension or similar technology. Or, the application can use the
|
|
sqlite3_create_function() interface to provide an alternative
|
|
implementation of sqlite_crypt() that computes a stronger password hash,
|
|
perhaps using a cryptographic hash function like SHA1.
|