rgw: mfa documentation

Signed-off-by: Yehuda Sadeh <yehuda@redhat.com>

doc/radosgw/index.rst

@@ -55,6 +55,7 @@ you may write data with one API and retrieve it with the other.
    Server-Side Encryption <encryption>
    Bucket Policy <bucketpolicy>
    Dynamic bucket index resharding <dynamicresharding>
+   Multi factor authentication <mfa>
    Sync Modules <sync-modules>
    Data Layout in RADOS <layout>
    troubleshooting

doc/radosgw/mfa.rst

@@ -0,0 +1,100 @@
+==========================================
+RGW Support for Multifactor Authentication
+==========================================
+
+.. versionadded:: Mimic
+
+The S3 multifactor authenticatioin (MFA) feature allows
+users to require the use of one-time password when removing
+objects on certain buckets. The buckets need to be configured
+with versioning and MFA enabled which can be done through
+the S3 api.
+
+Time-based one time password tokens can be assigned to a user
+through radosgw-admin. Each token has a secret seed, and a serial
+id that is assigned to it. Tokens are added to the user, can
+be listedm removed, and can also be re-synchronized.
+
+Multisite
+=========
+
+While the MFA IDs are set on the user's metadata, the
+actual MFA one time password configuration resides in the local zone's
+osds. Therefore, in a multi-site environment it is adviseable to use
+different tokens for different zones.
+
+
+Terminology
+=============
+
+-``TOTP``: Time-based One Time Password
+
+-``token serial``: a string that represents the ID of a TOTP token
+
+-``token seed``: the secret seed that is used to calculate the TOTP
+
+-``totp seconds``: the time resolution that is being used for TOTP generation
+
+-``totp window``: the number of TOTP tokens that are checked before and after the current token when validating token
+
+-``totp pin``: the valid value of a TOTP token at a certain time
+
+
+Admin commands
+==============
+
+Create a new MFA TOTP token
+------------------------------------
+
+::
+
+   # radosgw-admin mfa create --uid=<user-id> \
+                              --totp-serial=<serial> \
+                              --totp-seed=<seed> \
+                              [ --totp-seed-type=<hex|base32> ] \
+                              [ --totp-seconds=<num-seconds> ] \
+                              [ --totp-window=<twindow> ]
+
+List MFA TOTP tokens
+---------------------
+
+::
+
+   # radosgw-admin mfa list --uid=<user-id>
+
+
+Show MFA TOTP token
+------------------------------------
+
+::
+
+   # radosgw-admin mfa get --uid=<user-id> --totp-serial=<serial>
+
+
+Delete MFA TOTP token
+------------------------
+
+::
+
+   # radosgw-admin mfa remove --uid=<user-id> --totp-serial=<serial>
+
+
+Check MFA TOTP token
+--------------------------------
+
+Test a TOTP token pin, needed for validating that TOTP functions correctly. ::
+
+   # radosgw-admin mfa check --uid=<user-id> --totp-serial=<serial> \
+                             --totp-pin=<pin>
+
+
+Re-sync MFA TOTP token
+--------------------------------
+
+In order to re-sync the TOTP token (in case of time skew). This requires
+feeding two consecutive pins: the previous pin, and the current pin. ::
+
+   # radosgw-admin mfa resync --uid=<user-id> --totp-serial=<serial> \
+                              --totp-pin=<prev-pin> --totp=pin=<current-pin>
+
+