Autenticación es cualquier proceso por el cuál se verifica que uno es quien dice ser. Autorización es cualquier proceso en el cuál cualquiera está permitido a estar donde se quiera, o tener información la cuál se quiera tener.
Para información de control de acceso de forma genérica visiteHow to de Control de Acceso.
Si se tiene información en nuestra página web que sea información sensible o pensada para un grupo reducido de usuarios/personas, las técnicas que se describen en este manual, le servirán de ayuda para asegurarse de que las personas que ven esas páginas sean las personas que uno quiere.
Este artículo cubre la parte "estándar" de cómo proteger partes de un sitio web que muchos usarán.
Si de verdad es necesario que tus datos estén en un sitio seguro,
considera usar
Las directivas que se usan en este artículo necesitaran ponerse ya sea
en el fichero de configuración principal del servidor ( típicamente en
la sección
.htaccess).
Si planea usar los ficheros .htaccess , necesitarás
tener en la configuración global del servidor, una configuración que permita
poner directivas de autenticación en estos ficheros. Esto se hace con la
directiva
Ya que estamos hablando aquí de autenticación, necesitarás una directiva
O, si solo se van a poner las directivas directamente en la configuración principal del servidor, deberás tener, claro está, permisos de escritura en el archivo.
Y necesitarás saber un poco de como está estructurado el árbol de directorios de tu servidor, para poder saber donde se encuentran algunos archivos. Esto no debería ser una tarea difícil, aún así intentaremos dejarlo claro llegado el momento de comentar dicho aspecto.
También deberás de asegurarte de que los módulos
httpd.conf. Estos
dos módulos proporcionan directivas básicas y funcionalidades que son críticas
para la configuración y uso de autenticación y autorización en el servidor web.
Aquí está lo básico de cómo proteger con contraseña un directorio en tu servidor.
Primero, necesitarás crear un fichero de contraseña. Dependiendo de que proveedor de autenticación se haya elegido, se hará de una forma u otra. Para empezar, usaremos un fichero de contraseña de tipo texto.
Este fichero deberá estar en un sitio que no se pueda tener acceso desde
la web. Esto también implica que nadie pueda descargarse el fichero de
contraseñas. Por ejemplo, si tus documentos están guardados fuera de
/usr/local/apache/htdocs, querrás poner tu archivo de contraseñas en
/usr/local/apache/passwd.
Para crear el fichero de contraseñas, usa la utilidad
bin en donde sea que se ha
instalado el Apache. Si ha instalado Apache desde un paquete de terceros,
puede ser que se encuentre en su ruta de ejecución.
Para crear el fichero, escribiremos:
If /usr/local/apache2/bin/htpasswd
Next, you'll need to configure the server to request a
password and tell the server which users are allowed access.
You can do this either by editing the httpd.conf
file or using an .htaccess file. For example, if
you wish to protect the directory
/usr/local/apache/htdocs/secret, you can use the
following directives, either placed in the file
/usr/local/apache/htdocs/secret/.htaccess, or
placed in httpd.conf inside a <Directory
"/usr/local/apache/htdocs/secret"> section.
Let's examine each of those directives individually. The Basic, and this is the method
implemented by AuthType Digest. This method is implemented by
The
So, for example, once a client has authenticated in the
"Restricted Files" area, it will automatically
retry the same password for any area on the same server that is
marked with the "Restricted Files" Realm.
Therefore, you can prevent a user from being prompted more than
once for a password by letting multiple restricted areas share
the same realm. Of course, for security reasons, the client
will always need to ask again for the password whenever the
hostname of the server changes.
The file is the default value
for this directive. You'll need to use this directive if you are
choosing a different source for authentication, such as
The
Finally, the
The directives above only let one person (specifically
someone with a username of rbowen) into the
directory. In most cases, you'll want to let more than one
person in. This is where the
If you want to let more than one person in, you'll need to create a group file that associates group names with a list of users in that group. The format of this file is pretty simple, and you can create it with your favorite editor. The contents of the file will look like this:
That's just a list of the members of the group in a long line separated by spaces.
To add a user to your already existing password file, type:
You'll get the same response as before, but it will be
appended to the existing file, rather than creating a new file.
(It's the -c that makes it create a new password
file).
Now, you need to modify your .htaccess file to
look like the following:
Now, anyone that is listed in the group GroupName,
and has an entry in the password file, will be let in, if
they type the correct password.
There's another way to let multiple users in that is less specific. Rather than creating a group file, you can just use the following directive:
Using that rather than the Require user rbowen
line will allow anyone in that is listed in the password file,
and who correctly enters their password. You can even emulate
the group behavior here, by just keeping a separate password
file for each group. The advantage of this approach is that
Apache only has to check one file, rather than two. The
disadvantage is that you have to maintain a bunch of password
files, and remember to reference the right one in the
Because of the way that Basic authentication is specified, your username and password must be verified every time you request a document from the server. This is even if you're reloading the same page, and for every image on the page (if they come from a protected directory). As you can imagine, this slows things down a little. The amount that it slows things down is proportional to the size of the password file, because it has to open up that file, and go down the list of users until it gets to your name. And it has to do this every time a page is loaded.
A consequence of this is that there's a practical limit to how many users you can put in one password file. This limit will vary depending on the performance of your particular server machine, but you can expect to see slowdowns once you get above a few hundred entries, and may wish to consider a different authentication method at that time.
Because storing passwords in plain text files has the above problems, you may wish to store your passwords somewhere else, such as in a database.
dbm or dbd as your storage
format.
To select a dbm file rather than a text file, for example:
Other options are available. Consult the
With the introduction of the new provider based authentication and authorization architecture, you are no longer locked into a single authentication or authorization method. In fact any number of the providers can be mixed and matched to provide you with exactly the scheme that meets your needs. In the following example, both the file and LDAP based authentication providers are being used.
In this example the file provider will attempt to authenticate the user first. If it is unable to authenticate the user, the LDAP provider will be called. This allows the scope of authentication to be broadened if your organization implements more than one type of authentication store. Other authentication and authorization scenarios may include mixing one type of authentication with a different type of authorization. For example, authenticating against a password file yet authorizing against an LDAP directory.
Just as multiple authentication providers can be implemented, multiple authorization methods can also be used. In this example both file group authorization as well as LDAP group authorization is being used.
To take authorization a little further, authorization container
directives such as
The way that authorization can be applied is now much more flexible than just a single check against a single data store. Ordering, logic and choosing how authorization will be done is now possible.
Controlling how and in what order authorization will be applied
has been a bit of a mystery in the past. In Apache 2.2 a provider-based
authentication mechanism was introduced to decouple the actual
authentication process from authorization and supporting functionality.
One of the side benefits was that authentication providers could be
configured and called in a specific order which didn't depend on the
load order of the auth module itself. This same provider based mechanism
has been brought forward into authorization as well. What this means is
that the
With the introduction of authorization container directives
such as
By default all
Authentication by username and password is only part of the story. Frequently you want to let people in based on something other than who they are. Something such as where they are coming from.
The authorization providers all,
env, host and ip let you
allow or deny access based on other host based criteria such as
host name or ip address of the machine requesting a
document.
The usage of these providers is specified through the
where address is an IP address (or a partial IP address) or:
where domain_name is a fully qualified domain name (or a partial domain name); you may provide multiple addresses or domain names, if desired.
For example, if you have someone spamming your message board, and you want to keep them out, you could do the following:
Visitors coming from that address will not be able to see the content covered by this directive. If, instead, you have a machine name, rather than an IP address, you can use that.
And, if you'd like to block access from an entire domain, you can specify just part of an address or domain name:
Using not,
will only allow access, if all of negated conditions are true. In other words,
access will be blocked, if any of the negated conditions fails.
One of the side effects of adopting a provider based mechanism for
authentication is that the previous access control directives
The directives provided by
There may be times when authentication puts an unacceptable load
on a provider or on your network. This is most likely to affect users
of
This may offer a substantial performance boost to some users.
You should also read the documentation for
The various ciphers supported by Apache for authentication data are explained in Password Encryptions.
And you may want to look at the Access Control howto, which discusses a number of related topics.