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spnego SPN fix when contacting trusted domains

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cli_session_setup_spnego() was not taking into consideration the situation
where we're connecting to a trusted domain, specifically one (like W2K8)
which doesn't return a SPN in the NegTokenInit.

This caused two problems:

1) When guessing the SPN using kerberos_get_default_realm_from_ccache() we
were always using our default realm, not the realm of the domain we're
connecting to.

2) When falling back on NTLMSSP for authentication we were passing the name
of the domain we're connecting to for use in our credentials when we should be
passing our own workgroup name.

The fix for both was to split the single "domain" parameter into
"user_domain" and "dest_realm" parameters.  We use the "user_domain"
parameter to pass into the NTLM call, and we used "dest_realm" to create an SPN
if none was returned in the NegTokenInit2 packet.  If no "dest_realm" is
provided we assume we're connecting to our own domain and use the credentials
cache to build the SPN.

Since we have a reasonable guess at the SPN, I removed the check that defaults
us directly to NTLM when negHint is empty.
This commit is contained in:
Steven Danneman 2008-05-07 13:34:26 -07:00 committed by Gerald Carter
parent fd0ae47046
commit 8dc4e97977
2 changed files with 29 additions and 25 deletions
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42
source/libsmb/cliconnect.c
View File

@ -787,12 +787,16 @@ static NTSTATUS cli_session_setup_ntlmssp(struct cli_state *cli, const char *use
/****************************************************************************
Do a spnego encrypted session setup.
user_domain: The shortname of the domain the user/machine is a member of.
dest_realm: The realm we're connecting to, if NULL we use our default realm.
****************************************************************************/
ADS_STATUS cli_session_setup_spnego(struct cli_state *cli, const char *user,
const char *pass, const char *domain)
const char *pass, const char *user_domain,
const char * dest_realm)
{
char *principal;
char *principal = NULL;
char *OIDs[ASN1_MAX_OIDS];
int i;
BOOL got_kerberos_mechanism = False;
@ -813,8 +817,10 @@ ADS_STATUS cli_session_setup_spnego(struct cli_state *cli, const char *user,
/* there is 16 bytes of GUID before the real spnego packet starts */
blob = data_blob(cli->secblob.data+16, cli->secblob.length-16);
/* the server sent us the first part of the SPNEGO exchange in the negprot
reply */
/* The server sent us the first part of the SPNEGO exchange in the
* negprot reply. It is WRONG to depend on the principal sent in the
* negprot reply, but right now we do it. If we don't receive one,
* we try to best guess, then fall back to NTLM. */
if (!spnego_parse_negTokenInit(blob, OIDs, &principal)) {
data_blob_free(&blob);
return ADS_ERROR_NT(NT_STATUS_INVALID_PARAMETER);
@ -833,18 +839,6 @@ ADS_STATUS cli_session_setup_spnego(struct cli_state *cli, const char *user,
DEBUG(3,("got principal=%s\n", principal ? principal : "<null>"));
if (got_kerberos_mechanism && (principal == NULL)) {
/*
* It is WRONG to depend on the principal sent in the negprot
* reply, but right now we do it. So for safety (don't
* segfault later) disable Kerberos when no principal was
* sent. -- VL
*/
DEBUG(1, ("Kerberos mech was offered, but no principal was "
"sent, disabling Kerberos\n"));
cli->use_kerberos = False;
}
fstrcpy(cli->user_name, user);
#ifdef HAVE_KRB5
@ -896,7 +890,12 @@ ADS_STATUS cli_session_setup_spnego(struct cli_state *cli, const char *user,
return ADS_ERROR_NT(NT_STATUS_NO_MEMORY);
}
realm = kerberos_get_default_realm_from_ccache();
if (dest_realm) {
realm = SMB_STRDUP(dest_realm);
strupper_m(realm);
} else {
realm = kerberos_get_default_realm_from_ccache();
}
if (realm && *realm) {
if (asprintf(&principal, "%s$@%s",
machine, realm) < 0) {
@ -913,7 +912,8 @@ ADS_STATUS cli_session_setup_spnego(struct cli_state *cli, const char *user,
}
if (principal) {
rc = cli_session_setup_kerberos(cli, principal, domain);
rc = cli_session_setup_kerberos(cli, principal,
dest_realm);
if (ADS_ERR_OK(rc) || !cli->fallback_after_kerberos) {
SAFE_FREE(principal);
return rc;
@ -926,7 +926,8 @@ ADS_STATUS cli_session_setup_spnego(struct cli_state *cli, const char *user,
ntlmssp:
return ADS_ERROR_NT(cli_session_setup_ntlmssp(cli, user, pass, domain));
return ADS_ERROR_NT(cli_session_setup_ntlmssp(cli, user, pass,
user_domain));
}
/****************************************************************************
@ -1009,7 +1010,8 @@ NTSTATUS cli_session_setup(struct cli_state *cli,
/* if the server supports extended security then use SPNEGO */
if (cli->capabilities & CAP_EXTENDED_SECURITY) {
ADS_STATUS status = cli_session_setup_spnego(cli, user, pass, workgroup);
ADS_STATUS status = cli_session_setup_spnego(cli, user, pass,
workgroup, NULL);
if (!ADS_ERR_OK(status)) {
DEBUG(3, ("SPNEGO login failed: %s\n", ads_errstr(status)));
return ads_ntstatus(status);

12
source/nsswitch/winbindd_cm.c
View File

@ -729,13 +729,14 @@ static NTSTATUS cm_prepare_connection(const struct winbindd_domain *domain,
(*cli)->use_kerberos = True;
DEBUG(5, ("connecting to %s from %s with kerberos principal "
"[%s]\n", controller, global_myname(),
machine_krb5_principal));
"[%s] and realm [%s]\n", controller, global_myname(),
machine_krb5_principal, domain->alt_name));
ads_status = cli_session_setup_spnego(*cli,
machine_krb5_principal,
machine_password,
domain->name);
lp_workgroup(),
domain->alt_name);
if (!ADS_ERR_OK(ads_status)) {
DEBUG(4,("failed kerberos session setup with %s\n",
@ -755,12 +756,13 @@ static NTSTATUS cm_prepare_connection(const struct winbindd_domain *domain,
DEBUG(5, ("connecting to %s from %s with username "
"[%s]\\[%s]\n", controller, global_myname(),
domain->name, machine_account));
lp_workgroup(), machine_account));
ads_status = cli_session_setup_spnego(*cli,
machine_account,
machine_password,
domain->name);
lp_workgroup(),
NULL);
if (!ADS_ERR_OK(ads_status)) {
DEBUG(4, ("authenticated session setup failed with %s\n",
ads_errstr(ads_status)));