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Diffstat (limited to '')
| -rw-r--r-- | raddb/mods-available/dpsk | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/raddb/mods-available/dpsk b/raddb/mods-available/dpsk new file mode 100644 index 0000000..3cd8411 --- /dev/null +++ b/raddb/mods-available/dpsk @@ -0,0 +1,145 @@ +# -*- text -*- +# +# $Id$ + +# +# Calculate dynamic PSKs +# +# This module needs the following attributes as input: +# +# * control:Pre-Shared-Key - the PSK for the user +# * User-Name - the supplicant MAC in hex format, e.g. "abcdef012345" +# * Called-Station-MAC - the AP MAC in binary +# this attribute is set by the "rewrite_called_station_id" policy. +# * FreeRADIUS-802.1X-Anonce - from the AP +# * FreeRADIUS-802.1X-EAPoL-Key-Msg - from the AP +# +# Note that you MUST run the "rewrite_called_station_id" policy before calling this module. +# +# That policy MUST also create the Called-Station-MAC attribute. +# +# Then place the following configuration into the "authorize" section: +# +# authorize { +# ... +# rewrite_called_station_id +# +# update control { +# &PSK-Identity := "bob" +# &Pre-Shared-Key := "this-is-super-secret" +# } +# dpsk +# +# } +# +# And update the "authenticate" section to list the "dpsk" module: +# +# authenticate { +# ... +# dpsk +# ... +# } +# +# The module will return "fail" if the PSK is not correct. It will return "ok" +# if the PSK is correct. +# +# It also updates &reply:Pre-Shared-Key with the found key, along with +# &reply:PSK-Identity with the found identity. +# +# We STRONGLY RECOMMEND THAT NO ONE USE THIS MODULE. +# +# While it works, it needs to use a brute-force method to match MAC +# to PSK. That process is extremely slow, and scales very poorly. +# +# i.e. if you have 10 PSKs, it's not too bad. If you have 10,000 +# PSKs, then the module can comsume 100% of CPU trying to +# brute-force every PSK. +# +# This is a limitation of how DPSK works. There is no way to make it +# better. The only thing we've done is to add a cache which can help +# to minimize the amount of brute-force attempts. +# + +# +# The modules configuration. +# +dpsk { + # + # The maximum number of entries to cache. + # + # The cache is keyed by (supplicant MAC + SSID) + # + # The cache entry is the PSK-Identity and Pre-Sharedd-Key, + # and/or the PMK which are used to verify the information in + # the Access-Request. + # + cache_size = 1024 + + # + # The lifetime of an entry in the cache. + # + cache_lifetime = 86400 + + # + # PSKs can also be stored in a CSV file. The format of the file is: + # + # identity,psk,mac + # + # If there are commas in a field, then the field can be + # double quoted: "psk". + # + # The mac field is optional. If it exists, then that PSK + # will be used. It is highly recommended that the MAC *not* be placed + # into the CSV file. Instead, the MAC and PSK should be placed into a + # database. The server can then be configured to look up the MAC in the + # database, which returns the PSK. That way this module will only ever + # check one PSK, which is fast. + # + # i.e. the CSV file should only contain the small number of PSKs where + # you do not yet know the MAC. As soon as you know the MAC, you should + # put the MAC and PSK into a database, and then remove the MAC and PSK + # from the CSV file. + # + # NOTE: the file is opened and read from top to bottom for every + # new request which comes in. This process can be very slow! + # + # However, opening the file for every new request means that the + # server does not have to be reloaded when the file changes. Instead, + # the file can be generated, and then moved into place atomically: + # + # create csv file > psk.csv.new + # mv psk.csv.new psk.csv + # + # Any process which writes a new "psk.csv" file MUST NOT + # write to the file directly, as that will cause the dpsk + # module to read partial entries and fail. Instead, use "mv" + # to atomically overwrite the old file with a new one. + # + # Both "cache_size" and "filename" can be configured at the + # same time, which is recommended. When an entry in the file + # is found, the identity, PSK, and MAC are saved in the cache. + # + # If a cache entry is found, then the filename is NOT read. + # + # The resulting combination of features means that the module + # should be as fast as possible, given the limitations of DPSK. + # + # NOTE: Tests show that the module can do ~100K PSK / DPSK + # checks per second. This means that if you have 10,000 + # users and 10 packets a second, the system will be 100% busy + # checking PSKs. + # + # As a result, the DPSK functionality is scales poorly. It + # should be used only with a small number of PSKs (100s + # perhaps), and only at low packet rates. If the server is + # getting 1000 packets per second, then it can only handle + # 100 PSKs before running out of CPU. + # + # Using the cache will help substantially. But the cache is + # only in memory, which means that all cache entries are lost + # when the server restarts. As a result, the combination of + # number of PSKs and packet rates should be kept as low as + # possible. + # +# filename = "${modconfdir}/${..:name}/psk.csv" +} |