The user/group name "www-data", which is provided by the base-passwd package and used (most prominently) by the Apache httpd.conf configuration file, does not accurately reflect the role of the UID/GID it represents in contemporary Debian systems. It no longer represents file system "data", but rather is used as a UID/GID for network server processes.
"www-data" is also the only system user/group name containing a hyphen, which can cause problems in certain situations (in my own experience, when referring to user accounts within PostgreSQL). A perusal of the mailing lists indicates that there is plenty of confusion about this as well as problems caused by it. * * * In the past (slink? potato? I know potato = stable, but I'm running Woody now, and I'm more concerened with the future.) I seem to remember that the static HTML files in /var/www and the Apache log files were owned by www-data. I'm assuming that the www-data user and groups were created to give limited control over who could write files in directory trees accessed by HTTP server processes. I am not sure why the log files were given that ownership. At some point someone must have realized that (a.) having your web content writeable by your web server was a bad idea and (b.) Apache's logs are written by the controlling non-serving process and are therefore written as root, and changed this in the Debian Apache package. A current install of Debian's Apache package produces HTML files and log files owned by root. The ownership of the HTML files (and /var/www in general) should be owned by a non-root group so that you may delegate authority to non-root users. The (serving) apache processes themselves still run as user www-data by default, although this is configurable in httpd.conf. * * * The Debian Policy Manual states that system IDs "must be used on any Debian system only for the purpose for which they are allocated." www-data has devolved over the years so that it no longer meets this requirement. I have found no explicit reference to "www-data" in the Policy Manual sections "Users and Groups", "Daemons" and "Web Servers and applications". * * * I have searched debian-user and debian-policy back through late 1998 and have found the following (relevant) previous discussions. Inconclusive discussion from August, 2000, on whether or not there was a www-data policy: http://lists.debian.org/debian-policy/2000/debian-policy-200008/msg00059.html Discussion of Slink's bad www-data file permissions and process ownership: Complaints about the "-" in "www-data" casuing problems in PostgreSQL: http://lists.debian.org/debian-user/1999/debian-user-199909/msg00053.html http://lists.debian.org/debian-user/1999/debian-user-199911/msg01519.html * * * There should be a system user/group account for HTTP servers, but "www-data" is misleading in that it does not correspond to data. Plus it has that pesky hyphen. User "nobody" works for the simplest installations, but it hampers your ability to fine tune the access control granted to your server. I propose something like "httpd" or "http". There should also be a (separate) system user/group account for data that is accessed by HTTP servers. This would allow you to control which users may edit your web content. I propose something like "www" or even "wwwdata" (no hyphen). This same methodology should be applied to all system user/group accounts. Does the account refer to a process or file ownership or both? Is there a reason to split file ownership UID/GID from process ownership UID/GID? Thoughts? Matthew Whitworth ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ struct matthew_whitworth { char *email; char *url; } mw = { "[EMAIL PROTECTED]", "http://www.okcomputer.org/~matthew/"; }; -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
