Description of problem:
The crypt option definiton in the pam_userdb man page states that if value crypt is used, passwords should be stored in crypt(3) form. It supports, however, DES-crypt only, while crypt() supports a couple of other algorithms too according to the crypt(3) man page.

Version-Release number of selected component (if applicable):
pam-1.1.1-17.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1. $ man pam_userdb

Actual results:
incorrect definition of the crypt option

Expected results:
correct definition of the crypt option

Additional info:
In the PAM version in RHEL 6, there is a constraint before crypt() is called:

          if (data.dsize != 13) {
            compare = -2;

This constraint matches exactly what is expected from a DES-crypt encrypted password. Its length must be exactly 13 characters. That's why it doesn't support other algorithms even though crypt() does support them and crypt() is used. Some changes to the pam_userdb code would have to be done in order to support other algorithms too.

Looking at PAM in RHEL 7, this constraint is changed along with some other changes in the relevant part of the code, so it's possible that PAM in RHEL 7 supports other algorithms (I didn't try it, that is just what I guess from the code):

          if (data.dsize < 13) {
            compare = -2;

Man pages for RHEL 6 and RHEL 7 define the crypt option in the same way though.