X-Git-Url: http://git.treefish.org/fex.git/blobdiff_plain/c65ee6f7429eff9a7f58aad7c0aec858ad473092..20160328:/doc/concept diff --git a/doc/concept b/doc/concept index 26ad9da..fde9902 100644 --- a/doc/concept +++ b/doc/concept @@ -17,7 +17,7 @@ Main features of F*EX * full-users can create subusers, who can send only to this full-user * full-users can create groups, an analogy to mailing lists, but for files * self registration possible for internal and external users - * maintenance-free: no admin interaction necessary + * maintenance-free: no admin interaction necessary * sending to multiple recipients needs storage on the server only once * quotas for sending and receiving * F*EX is a HTTP web-service and needs no firewall-tunnels @@ -40,7 +40,7 @@ Main features of F*EX The end user normally uses F*EX with his web browser and the URLs http://YOURFEXSERVER/fup (file upload) and http://YOURFEXSERVER/fop (file -download). +download). F*EX is not an anonymous service (exception: "public upload" and @@ -52,7 +52,7 @@ program "fac" (F*EX admin control) or http://YOURFEXSERVER/fac Alternativly the users can register theirselves with http://YOURFEXSERVER/fur (F*EX user registration), if the admin allows them to do so. This is done by setting the variables @local_domains and @local_hosts in FEXHOME/lib/fex.ph -Example: +Example: @local_hosts = qw(127.0.0.1 10.10.100.0-10.10.255.255); @local_domains = qw(rus.uni-stuttgart.de flupp.org); @@ -75,12 +75,12 @@ the local recipient domains. For example: F*EX full users can create one time upload URLs with -http://YOURFEXSERVER/fuc +http://YOURFEXSERVER/fuc With such a URL a foreign user can send this F*EX full user a single file. F*EX full users can theirselves register "subusers" with -http://YOURFEXSERVER/fuc +http://YOURFEXSERVER/fuc Subusers can only fex to their full-user, not to any others, and they cannot create other subusers. @@ -95,7 +95,7 @@ he cannot change anymore his default settings (KEEP, AUTODELETE, etc) The F*EX user is the same as the "sender" in the fup CGI and the "from" -parameter in the F*EX URL. +parameter in the F*EX URL. The (confusing) naming scheme is historically based :-) @@ -106,7 +106,7 @@ email. You do not need to build F*EX URLs manually, they are generated by the -F*EX programs. +F*EX programs. A F*EX session is based on unique URL parameters or POST variables (FROM, @@ -121,18 +121,18 @@ A SKEY is made of md5_hex("$mainuser:$subuser:$subuserid") A GKEY is made of md5_hex("$mainuser:$groupname:$groupuser:$groupuserid") Note: the AKEY, SKEY and GKEY always can be stolen by a network sniffer! -If you need true security, then you have to use https instead of http! +If you need true security, then you have to use https instead of http! After download the file will be deleted after a grace time of 1 minute. This grace time allows a recipient to get the file again if he had -problems in saving it. +problems in saving it. With the fexsend client the sender can change this behavior: option -D means "delay autodelete": do not delete the the file directly after download, but with the nightly fex_cleanup cronjob. More downloads are possible only from the same client (identified by cookie or ip -address). +address). option -K means "keep file": do not delete the file after download, but only after expiration date (normally 5 days). More downloads are possible @@ -164,7 +164,7 @@ requires (HTTP) authorization. The credentials are the F*EX user email and auth-ID. See extra documentation SSL for using https. -If you want to have encrypted emails, then you need a GPG public key for +If you want to have encrypted emails, then you need a GPG public key for the user fex. Create it with "gpg --gen-key" (use fex@YOURFEXSERVER as the user or the $bcc address from fex.ph if you have set it, see below). Next, the user has to upload his public key via webinterface "user config & @@ -206,14 +206,14 @@ below! FEXHOME contains: - spool/ spool directory and user data + spool/ spool directory and user data htdocs/ directory for generic download files bin/ directory for programs cgi-bin/ directory for CGI programs lib/ directory for library and config files doc/ additional documentation locale/ alternative language installation - + Files in spool: @@ -240,7 +240,7 @@ Files in spool: $user/@KEEP keep default $user/@LOCALE locale default $user/@CAPTIVE user must not change his settings - $user/@FEXYOURSELF user can only fex to himself via + $user/@FEXYOURSELF user can only fex to himself via web interface $to/$from/$file/upload file data in upload progress $to/$from/$file/filename original file name @@ -294,7 +294,7 @@ This is done via UKEY, a unique upload identifier. The download key (DKEY) is a unique identifier for - guess what - downloading. It also prevents an attacker to get the file, because only the recipient knows the DKEY as part of the download URL from the -notification email. +notification email. XKEY is an optional extra download key to have a short download URL in shape http://YOURFEXSERVER//XKEY @@ -302,7 +302,7 @@ The XKEY always starts with // and is provided as a COMMENT by the client. Example: fexsend schwuppdiwupp.jpg // The user has to realize that such URLs have very low security. -If you need to trace a F*EX request, then set +If you need to trace a F*EX request, then set $debug = 1; in fex.ph and look in ~/spool/.debug/ for the correspondening files. @@ -323,7 +323,7 @@ In this case "From: $admin" will be used in the notification emails. F*EX comes with its own web server: fexsrv Standard web servers like apache have been proven problematic, either in -speed or because of a 2-GB-limit. +speed or because of a 2-GB-limit. It is not possible to use the F*EX CGIs with an alternative web server, because the F*EX CGIs need special fexsrv features. @@ -331,7 +331,7 @@ because the F*EX CGIs need special fexsrv features. xinetd starts fexsrv for every new connection, which then executes the CGIs fup (file upload), fop (file output), fuc (fex user control), foc (fex operation control), fac (fex admin control), fur (fex user -registration) and sex (stream exchange). +registration) and sex (stream exchange). SEX has the opposite authorization model of FEX: The sender does not @@ -342,7 +342,7 @@ otherwise. The client programs for sexing are sexsend and sexget. You can call them also fuckyou and fuckme :-) -With the F*EX client fexsend you can have a streaming file transfer with +With the F*EX client fexsend you can have a streaming file transfer with spooling: on client side there is no temporary buffer file (archive), but the data is sent directly to the F*EX server. This saves time and disk space on the client. @@ -383,14 +383,16 @@ directory. You can name single IPs, also as IP ranges (example: 129.69.0.0-129.69.255.255) dop is not a regular CGI program (like fup or fop), but a sub-program of -fexsrv. +fexsrv. *.html files may contain $VARIABLES$ which will be substituted with the value of the corresponding environment variable. See example $SERVER_ADMIN$ in FEXHOME/htdocs/index.html *.html files may contain <> (even multiline) which will be -evaluated. See example FEXHOME/htdocs/dynamic.html +evaluated and its output will be placed in. Same goes for <<>> +but without output catching. +See example FEXHOME/htdocs/dynamic.html This perl-code must not contain '>>' strings itself! Pay attention: do not place security relevant data inside << >> because it will be delivered to the client if the URL ends with '!'! See example: @@ -462,7 +464,7 @@ Or to delete inactive users you can put in fex.ph: $account_expire = "365:delete"; This deletes user accounts automatically which have been inactive for 365 -days. +days. Of course you can use any number of days. @@ -489,7 +491,7 @@ because most proxies do not support persistant tcp sessions. See fex-client_2.pdf for the F*EX protocol specification. To understand and trace the F*EX protocol you can use fexsend with the -v -option. +option. Example (--> means send to server, <-- means receive from server): @@ -504,47 +506,47 @@ TCPCONNECT to fex.rus.uni-stuttgart.de <-- X-SID: 8p2Y2qa2 <-- X-Timeout: 30 <-- Content-Length: 0 -<-- +<-- --> HEAD /fop/framstag@flupp.org/framstag@fex.rus.uni-stuttgart.de/X.png??ID=MD5H:226e896d0adab86892957aa8158b37ba HTTP/1.1 --> <-- HTTP/1.1 200 OK <-- Content-Length: 0 <-- X-Size: 0 <-- X-Features: SID,CHECKRECIPIENT,GROUPS,QUOTA,FILEID,MULTIPOST,XKEY -<-- +<-- --> POST /fup HTTP/1.1 --> Host: fex.rus.uni-stuttgart.de --> User-Agent: fexsend (Ubuntu 8.04.4 LTS) --> Content-Length: 149935162 --> Content-Type: multipart/form-data; boundary=JhUOtQ3sgV5ZcHJzrTny523nBFqgUNvSAOUHoRMTdZfGpAjs ---> +--> --> --JhUOtQ3sgV5ZcHJzrTny523nBFqgUNvSAOUHoRMTdZfGpAjs --> Content-Disposition: form-data; name="FROM" ---> +--> --> framstag@fex.rus.uni-stuttgart.de --> --JhUOtQ3sgV5ZcHJzrTny523nBFqgUNvSAOUHoRMTdZfGpAjs --> Content-Disposition: form-data; name="TO" ---> +--> --> framstag@flupp.org --> --JhUOtQ3sgV5ZcHJzrTny523nBFqgUNvSAOUHoRMTdZfGpAjs --> Content-Disposition: form-data; name="ID" ---> +--> --> MD5H:226e896d0adab86892957aa8158b37ba --> --JhUOtQ3sgV5ZcHJzrTny523nBFqgUNvSAOUHoRMTdZfGpAjs --> Content-Disposition: form-data; name="FILESIZE" ---> +--> --> 149934400 --> --JhUOtQ3sgV5ZcHJzrTny523nBFqgUNvSAOUHoRMTdZfGpAjs --> Content-Disposition: form-data; name="FILE"; filename="X.png" --> Content-Type: application/octet-stream --> Content-Length: 149934400 --> X-File-ID: 1283077463 ---> +--> --> (file content) --> --JhUOtQ3sgV5ZcHJzrTny523nBFqgUNvSAOUHoRMTdZfGpAjs-- <-- Location: http://fex.rus.uni-stuttgart.de/fop/CoVhikzk/X.png <-- X-Recipient: framstag@flupp.org (autodelete=YES,keep=5) -<-- +<-- Comment on the HEAD request above: The client fexsend sends it to request whether the file has been sent @@ -560,7 +562,7 @@ CHECKRECIPIENT is a HTTP POST request to check whether the recpient's email address is valid to the server. GET ADDRESS_BOOK is a HTTP GET request to check if the recipient with a short address (= address without @) is an alias in the senders server -address book. +address book. Please use "fexsend -v" by yourself to see the whole protocol dialoge. Many HTTP proxies have a POST limit, which is often at 2 GB, but sometimes