X-Git-Url: https://git.treefish.org/fex.git/blobdiff_plain/97b87610331f53e756d032ad21db786037f921a1..20160919:/doc/concept diff --git a/doc/concept b/doc/concept index 26ad9da..6203c43 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 @@ -51,8 +51,8 @@ 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: +setting the variables @local_domains and @local_hosts in $FEXHOME/lib/fex.ph +Example: @local_hosts = qw(127.0.0.1 10.10.100.0-10.10.255.255); @local_domains = qw(rus.uni-stuttgart.de flupp.org); @@ -75,12 +75,12 @@ the local recipient domains. For example: F*EX full users can create one time upload URLs with -http://YOURFEXSERVER/fuc +http://YOURFEXSERVER/fuc With such a URL a foreign user can send this F*EX full user a single file. F*EX full users can theirselves register "subusers" with -http://YOURFEXSERVER/fuc +http://YOURFEXSERVER/fuc Subusers can only fex to their full-user, not to any others, and they cannot create other subusers. @@ -95,7 +95,7 @@ he cannot change anymore his default settings (KEEP, AUTODELETE, etc) The F*EX user is the same as the "sender" in the fup CGI and the "from" -parameter in the F*EX URL. +parameter in the F*EX URL. The (confusing) naming scheme is historically based :-) @@ -106,7 +106,7 @@ email. You do not need to build F*EX URLs manually, they are generated by the -F*EX programs. +F*EX programs. A F*EX session is based on unique URL parameters or POST variables (FROM, @@ -121,18 +121,18 @@ A SKEY is made of md5_hex("$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 @@ -146,7 +146,7 @@ and more than once (until expiration date). If you want "delay autodelete" to be the default behaviour for all users and each transfer then set $autodelete = 'DELAY'; # or 'NO' for no autodelete -in FEXHOME/lib/fex.ph +in $FEXHOME/lib/fex.ph In addition, you can add to the "Recipient(s)" field of the fup CGI: ":autodelete=delay" or ":autodelete=no" or ":keep=x" (where x is the number @@ -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 & @@ -193,27 +193,27 @@ The administrator can also forbid a user to fex to any recipient address, but the allowed ones with: fac -r USER -By standard installation the base directory FEXHOME is the same as the -login HOME of user fex, but you can move it if you want. FEXHOME is +By standard installation the base directory $FEXHOME is the same as the +login HOME of user fex, but you can move it if you want. $FEXHOME is determined by the full path of fexsrv as configured in -/etc/xinetd.d/fex . Change this when you move FEXHOME! +/etc/xinetd.d/fex . Change this when you move $FEXHOME! You can also add (name based) virtual hosts with fac. -Do not give write permission to any other user to any file in FEXHOME or +Do not give write permission to any other user to any file in $FEXHOME or below! -FEXHOME contains: +$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 @@ -273,7 +273,7 @@ A registered full F*EX user is identified by the file $spooldir/$from/@ Only if this file contains his auth-ID this user is able to send files to others. Otherwise he is just an unpriviledged recipient. -You can customize the upload CGI fup by editing FEXHOME/lib/fup.pl +You can customize the upload CGI fup by editing $FEXHOME/lib/fup.pl Additional directories in spool: @@ -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. @@ -362,13 +362,13 @@ For streaming receiving you can use "fexget -s-" or "wget -O-". fexsrv also can do generic document output (via dop) like a normal web -server. For this, your files must be under FEXHOME/htdocs and they must -not have the same name as the CGIs under FEXHOME/cgi-bin, because the CGIs +server. For this, your files must be under $FEXHOME/htdocs and they must +not have the same name as the CGIs under $FEXHOME/cgi-bin, because the CGIs have priority. For security reasons, documents to be delivered by dop: - the file must be readable by group or world -- the file must be in FEXHOME/htdocs or a directory specified by @doc_dirs +- the file must be in $FEXHOME/htdocs or a directory specified by @doc_dirs - the filename must not start with a "." - the filename must not contain a "@" - the filename must not end with "~" @@ -383,17 +383,27 @@ 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 +$SERVER_ADMIN$ in $FEXHOME/htdocs/index.html *.html files may contain <> (even multiline) which will be -evaluated. See example FEXHOME/htdocs/dynamic.html -This perl-code must not contain '>>' strings itself! +evaluated. The output from print and printf statements will be placed +in. If the perl-code does not end with a ";" then its return value is also +added to the output. + +Same goes for <<>> but without output catching. + +This perl-code must not contain ">>" strings itself! + +See example $FEXHOME/htdocs/dynamic.html + +To chainload external perl-code do not use "require" but "do" statement. Pay attention: do not place security relevant data inside << >> because it -will be delivered to the client if the URL ends with '!'! See example: +will be delivered to the client if the URL ends with a "!" character, see +example: http://fex.rus.uni-stuttgart.de/index.html http://fex.rus.uni-stuttgart.de/index.html! @@ -462,7 +472,7 @@ 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 +499,7 @@ 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 +514,47 @@ 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 +570,7 @@ 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