On 28 Feb 2005 20:17:58 EST, Tim Daneliuk <[EMAIL PROTECTED]> wrote: [...] >Given a username and a password (plain text): > > 1) Validate that the password is correct for that user *without actually > logging in*. > The 'pwd' module probably won't be able (and won't try) to read the shadow password file, so 'pwd' won't be of use. There may not be a Python module which handles your local authentication scheme (there's a 'krb5' module for Kerberos authentication), so you may need to write one. The best approach may be to write an extension module in C or C++ which wraps around whatever local authentication functions are appropriate (e.g. a 'pam' module for PAM, an 'auth' module for BSD). You'd only need to wrap the functions needed for simple pass/fail authentication (e.g. auth_userokay), but the other functions could easily be added to the extension later if needed.
The process that calls the authentication functions will probably need special access privileges so that the functions can succesfully accept or reject the password. The man pages for the authentication functions should have details. For example, auth_userokay calls getpwnam, which requires the effective uid to be 0 (or, on some systems, the user to be in the "_shadow" group) for it to include the encrypted password in the passwd entry. If you're not sure what authentication scheme your system uses, try `man -s 3 authenticate` or examine "/usr/src/usr.bin/login/login.c". extending Python: http://www.python.org/doc/2.4/ext/ext.html Python/C API: http://www.python.org/doc/2.4/api/api.html Information on Linux-PAM http://www.kernel.org/pub/linux/libs/pam/ You could even add support for the full authentication API to your module and contribute the extension to the Python community. http://www.python.org/download/Contributed.html. > 2) If the password is valid, return a list of all the groups the user > belongs to. > Otherwise, return some error string. > [...] >I can do 2) by brute force - just parse through /etc/group - but this >misses the primary group a given user may belong to - and that requires >also scanning /etc/passwd and then looking up the corresponding primary >group in /etc/group. Is there a better way? > Slightly better would be to use the grp and pwd modules: http://www.python.org/doc/2.4/lib/module-grp.html http://www.python.org/doc/2.4/lib/module-pwd.html Even better would be to write an extension or add to the grp module to wrap around local group database access functions (e.g. getgrouplist). See the 'getgrouplist' man page for more information and examine the source of the `groups` command (probably "/usr/src/usr.bin/groups/groups.c") or `id` command (should be "/usr/src/usr.bin/id/id.c") for other group DB access functions. You could also call the `groups` command via 'os.popen(...)'. -- http://mail.python.org/mailman/listinfo/python-list
