(ITS#9126) add: pwdChangedTime leads to seg fault

[michael@stroeder.com]

Full_Name: Michael Str.der
Version: 2.4.48 / RE24 branch
OS: openSUSE Linux
URL: 
Submission from: (NULL) (213.240.182.73)


slapd seg faults in case the client sends a modify operation like this (let me
know if you need a stack trace):

----------------------------- snip -----------------------------
$ ldapmodify -e relax << EOF
dn: uid=test42,ou=Testing,dc=stroeder,dc=de
changetype: modify
add: pwdChangedTime
pwdChangedTime: 19721101000000Z

EOF
SASL/EXTERNAL authentication started
SASL username: gidNumber=100+uidNumber=1000,cn=peercred,cn=external,cn=auth
SASL SSF: 0
modifying entry "uid=test42,ou=Testing,dc=stroeder,dc=de"
ldap_result: Can't contact LDAP server (-1)
----------------------------- snip -----------------------------

Note that this only happens in case the userPassword was *freshly* set via
Password Modify ext. op.

If the client sends a modify operation with 'replace: pwdChangedTime' this works
correctly and after that 'add: pwdChangedTime' is correctly rejected:

----------------------------- snip -----------------------------
$ ldapmodify -e relax << EOF
dn: uid=test42,ou=Testing,dc=stroeder,dc=de
changetype: modify
replace: pwdChangedTime
pwdChangedTime: 19721101000000Z

EOF
SASL/EXTERNAL authentication started
SASL username: gidNumber=100+uidNumber=1000,cn=peercred,cn=external,cn=auth
SASL SSF: 0
modifying entry "uid=test42,ou=Testing,dc=stroeder,dc=de"

$ ldapmodify -e relax << EOF
dn: uid=test42,ou=Testing,dc=stroeder,dc=de
changetype: modify
add: pwdChangedTime
pwdChangedTime: 19721101000000Z

EOF
SASL/EXTERNAL authentication started
SASL username: gidNumber=100+uidNumber=1000,cn=peercred,cn=external,cn=auth
SASL SSF: 0
modifying entry "uid=test42,ou=Testing,dc=stroeder,dc=de"
ldap_modify: Type or value exists (20)
	additional info: modify/add: pwdChangedTime: value #0 already exists
----------------------------- snip -----------------------------