Memory leak in create_user_from_session

This goes for version 5.2 and 5.3. Did not check
earlier versions.

In create_user_from_session you have

if \(session->securityAuthLocalKey \!= NULL
    && session->securityAuthLocalKeyLen \!= 0\) \{
    /\* already localized key passed in.  use it \*/
    if \(memdup\(&user->authKey, session-

securityAuthLocalKey,
session->securityAuthLocalKeyLen) !
= SNMPERR_SUCCESS) {
usm_free_user(user);
return SNMPERR_GENERR;
}
user->authKeyLen = session-
securityAuthLocalKeyLen;
} else if (session->securityAuthKey != NULL
&& session->securityAuthKeyLen != 0) {
SNMP_FREE(user->authKey);
user->authKey = (u_char *) calloc(1,
USM_LENGTH_KU_HASHBLOCK);
...

Note that this code is reached in case the usmUser is
found in the list, and therefore user->authKey was
previously allocated. Therefore there should be an
SNMP_FREE before the memdup is used, the same as there
is an SNMP_FREE before the "calloc".

The same goes for both authKey and privKey.

I checked it with purify and after adding the
SNMP_FREE the issue was resolved.

Here is the revised code:

if \(session->securityAuthLocalKey \!= NULL
    && session->securityAuthLocalKeyLen \!= 0\) \{
    /\* already localized key passed in.  use it \*/
    SNMP\_FREE\(user->authKey\);
    if \(memdup\(&user->authKey, session-

securityAuthLocalKey,
session->securityAuthLocalKeyLen) !
= SNMPERR_SUCCESS) {
usm_free_user(user);
return SNMPERR_GENERR;
}
user->authKeyLen = session-
securityAuthLocalKeyLen;
} else if (session->securityAuthKey != NULL
&& session->securityAuthKeyLen != 0) {
SNMP_FREE(user->authKey);
user->authKey = (u_char *) calloc(1,
USM_LENGTH_KU_HASHBLOCK);
...