I created a new user via the useradd command. When I try to log in to that account, SELinux blocks the login. From the audit.log, here are some errors that could be related:
type=USER_LOGIN msg=audit(1336332077.728:477): pid=0 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='uid=1001 exe="/usr/libexec/gdm-session-worker" hostname=? addr=? terminal=/dev/tty3 res=failed'
type=USER_LOGIN msg=audit(1336332097.295:479): pid=0 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='uid=1001 exe="/usr/libexec/gdm-session-worker" hostname=? addr=? terminal=/dev/tty3 res=failed'
type=USER_LOGIN msg=audit(1336335890.933:99): pid=0 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='uid=1001 exe="/usr/libexec/gdm-session-worker" hostname=? addr=? terminal=/dev/tty2 res=failed'
type=USER_LOGIN msg=audit(1336335906.109:101): pid=0 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='uid=1001 exe="/usr/libexec/gdm-session-worker" hostname=? addr=? terminal=/dev/tty2 res=failed'
type=USER_CHAUTHTOK msg=audit(1336335990.816:118): pid=0 uid=0 auid=1000 ses=5 subj=unconfined_u:unconfined_r

asswd_t:s0-s0:c0.c1023 msg='op=change password id=1001 exe="/usr/bin/passwd" hostname=? addr=? terminal=pts/0 res=failed'
type=USER_CHAUTHTOK msg=audit(1336336016.307:120): pid=0 uid=0 auid=1000 ses=5 subj=unconfined_u:unconfined_r

asswd_t:s0-s0:c0.c1023 msg='op=change password id=1001 exe="/usr/bin/passwd" hostname=? addr=? terminal=pts/0 res=failed'