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samba-mirror/source/smbd/sesssetup.c
Andrew Bartlett a8a53c08f7 Ensure that 'use spnego' restricts, rather than just advises our clients.
This means that if a hole is found in the spnego code, we can tell people
to just set 'use spengo' in their config file while we sort it out.

Other than that, preventing 'unusual' behaviour is always a good thing.

Andrew Bartlett
-

760 lines
20 KiB
C

/*
Unix SMB/Netbios implementation.
Version 3.0
handle SMBsessionsetup
Copyright (C) Andrew Tridgell 1998-2001
Copyright (C) Andrew Bartlett 2001
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
uint32 global_client_caps = 0;
static auth_authsupplied_info *ntlmssp_auth_info;
/****************************************************************************
Add the standard 'Samba' signature to the end of the session setup.
****************************************************************************/
static void add_signature(char *outbuf)
{
char *p;
p = smb_buf(outbuf);
p += srvstr_push(outbuf, p, "Unix", -1, STR_TERMINATE);
p += srvstr_push(outbuf, p, "Samba", -1, STR_TERMINATE);
p += srvstr_push(outbuf, p, lp_workgroup(), -1, STR_TERMINATE);
set_message_end(outbuf,p);
}
/****************************************************************************
Do a 'guest' logon, getting back the
****************************************************************************/
static NTSTATUS check_guest_password(auth_serversupplied_info **server_info)
{
auth_authsupplied_info *auth_info;
auth_usersupplied_info *user_info = NULL;
NTSTATUS nt_status;
char chal[8];
ZERO_STRUCT(chal);
DEBUG(3,("Got anonymous request\n"));
make_user_info_guest(&user_info);
make_auth_info_fixed(&auth_info, chal);
nt_status = check_password(user_info, auth_info, server_info);
free_auth_info(&auth_info);
free_user_info(&user_info);
return nt_status;
}
#ifdef HAVE_KRB5
/****************************************************************************
reply to a session setup spnego negotiate packet for kerberos
****************************************************************************/
static int reply_spnego_kerberos(connection_struct *conn,
char *inbuf, char *outbuf,
int length, int bufsize,
DATA_BLOB *secblob)
{
DATA_BLOB ticket;
char *client, *p;
const struct passwd *pw;
char *user;
int sess_vuid;
NTSTATUS ret;
DATA_BLOB auth_data;
auth_serversupplied_info *server_info = NULL;
ADS_STRUCT *ads;
if (!spnego_parse_krb5_wrap(*secblob, &ticket)) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
ads = ads_init(NULL, NULL, NULL, NULL);
ret = ads_verify_ticket(ads, &ticket, &client, &auth_data);
if (!NT_STATUS_IS_OK(ret)) {
DEBUG(1,("Failed to verify incoming ticket!\n"));
ads_destroy(&ads);
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
DEBUG(3,("Ticket name is [%s]\n", client));
p = strchr_m(client, '@');
if (!p) {
DEBUG(3,("Doesn't look like a valid principal\n"));
ads_destroy(&ads);
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
*p = 0;
if (strcasecmp(p+1, ads->realm) != 0) {
DEBUG(3,("Ticket for incorrect realm %s\n", p+1));
ads_destroy(&ads);
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
ads_destroy(&ads);
user = client;
/* the password is good - let them in */
pw = smb_getpwnam(user,False);
if (!pw) {
DEBUG(1,("Username %s is invalid on this system\n",user));
return ERROR_NT(NT_STATUS_NO_SUCH_USER);
}
if (!make_server_info_pw(&server_info,pw)) {
DEBUG(1,("make_server_info_from_pw failed!\n"));
return ERROR_NT(NT_STATUS_NO_MEMORY);
}
sess_vuid = register_vuid(server_info, user);
free_server_info(&server_info);
if (sess_vuid == -1) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
set_message(outbuf,4,0,True);
SSVAL(outbuf, smb_vwv3, 0);
add_signature(outbuf);
SSVAL(outbuf,smb_uid,sess_vuid);
SSVAL(inbuf,smb_uid,sess_vuid);
return chain_reply(inbuf,outbuf,length,bufsize);
}
#endif
/****************************************************************************
send a security blob via a session setup reply
****************************************************************************/
static BOOL reply_sesssetup_blob(connection_struct *conn, char *outbuf,
DATA_BLOB blob)
{
char *p;
set_message(outbuf,4,0,True);
/* we set NT_STATUS_MORE_PROCESSING_REQUIRED to tell the other end
that we aren't finished yet */
SIVAL(outbuf, smb_rcls, NT_STATUS_V(NT_STATUS_MORE_PROCESSING_REQUIRED));
SSVAL(outbuf, smb_vwv0, 0xFF); /* no chaining possible */
SSVAL(outbuf, smb_vwv3, blob.length);
p = smb_buf(outbuf);
memcpy(p, blob.data, blob.length);
p += blob.length;
p += srvstr_push(outbuf, p, "Unix", -1, STR_TERMINATE);
p += srvstr_push(outbuf, p, "Samba", -1, STR_TERMINATE);
p += srvstr_push(outbuf, p, lp_workgroup(), -1, STR_TERMINATE);
set_message_end(outbuf,p);
return send_smb(smbd_server_fd(),outbuf);
}
/****************************************************************************
reply to a session setup spnego negotiate packet
****************************************************************************/
static int reply_spnego_negotiate(connection_struct *conn,
char *inbuf,
char *outbuf,
int length, int bufsize,
DATA_BLOB blob1)
{
char *OIDs[ASN1_MAX_OIDS];
DATA_BLOB secblob;
int i;
uint32 ntlmssp_command, neg_flags;
DATA_BLOB sess_key, chal, spnego_chal;
DATA_BLOB cryptkey;
BOOL got_kerberos = False;
/* parse out the OIDs and the first sec blob */
if (!parse_negTokenTarg(blob1, OIDs, &secblob)) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
for (i=0;OIDs[i];i++) {
DEBUG(3,("Got OID %s\n", OIDs[i]));
if (strcmp(OID_KERBEROS5, OIDs[i]) == 0 ||
strcmp(OID_KERBEROS5_OLD, OIDs[i]) == 0) {
got_kerberos = True;
}
free(OIDs[i]);
}
DEBUG(3,("Got secblob of size %d\n", secblob.length));
#ifdef HAVE_KRB5
if (got_kerberos) {
int ret = reply_spnego_kerberos(conn, inbuf, outbuf,
length, bufsize, &secblob);
data_blob_free(&secblob);
return ret;
}
#endif
/* parse the NTLMSSP packet */
#if 0
file_save("secblob.dat", secblob.data, secblob.length);
#endif
if (!msrpc_parse(&secblob, "CddB",
"NTLMSSP",
&ntlmssp_command,
&neg_flags,
&sess_key)) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
data_blob_free(&secblob);
data_blob_free(&sess_key);
if (ntlmssp_command != NTLMSSP_NEGOTIATE) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
DEBUG(3,("Got neg_flags=%08x\n", neg_flags));
if (!make_auth_info_subsystem(&ntlmssp_auth_info)) {
return ERROR_NT(NT_STATUS_NO_MEMORY);
}
cryptkey = auth_get_challenge(ntlmssp_auth_info);
/* Give them the challenge. For now, ignore neg_flags and just
return the flags we want. Obviously this is not correct */
neg_flags = NTLMSSP_NEGOTIATE_UNICODE |
NTLMSSP_NEGOTIATE_LM_KEY |
NTLMSSP_NEGOTIATE_NTLM;
msrpc_gen(&chal, "Cddddbdddd",
"NTLMSSP",
NTLMSSP_CHALLENGE,
0,
0x30, /* ?? */
neg_flags,
cryptkey.data, cryptkey.length,
0, 0, 0,
0x3000); /* ?? */
if (!spnego_gen_challenge(&spnego_chal, &chal, &chal)) {
DEBUG(3,("Failed to generate challenge\n"));
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
/* now tell the client to send the auth packet */
reply_sesssetup_blob(conn, outbuf, spnego_chal);
data_blob_free(&chal);
data_blob_free(&cryptkey);
data_blob_free(&spnego_chal);
/* and tell smbd that we have already replied to this packet */
return -1;
}
/****************************************************************************
reply to a session setup spnego auth packet
****************************************************************************/
static int reply_spnego_auth(connection_struct *conn, char *inbuf, char *outbuf,
int length, int bufsize,
DATA_BLOB blob1)
{
DATA_BLOB auth;
char *workgroup = NULL, *user = NULL, *machine = NULL;
DATA_BLOB lmhash, nthash, sess_key;
DATA_BLOB plaintext_password = data_blob(NULL, 0);
uint32 ntlmssp_command, neg_flags;
NTSTATUS nt_status;
int sess_vuid;
auth_usersupplied_info *user_info = NULL;
auth_serversupplied_info *server_info = NULL;
if (!spnego_parse_auth(blob1, &auth)) {
#if 0
file_save("auth.dat", blob1.data, blob1.length);
#endif
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
/* now the NTLMSSP encoded auth hashes */
if (!msrpc_parse(&auth, "CdBBUUUBd",
"NTLMSSP",
&ntlmssp_command,
&lmhash,
&nthash,
&workgroup,
&user,
&machine,
&sess_key,
&neg_flags)) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
data_blob_free(&auth);
data_blob_free(&sess_key);
DEBUG(3,("Got user=[%s] workgroup=[%s] machine=[%s] len1=%d len2=%d\n",
user, workgroup, machine, lmhash.length, nthash.length));
#if 0
file_save("nthash1.dat", nthash.data, nthash.length);
file_save("lmhash1.dat", lmhash.data, lmhash.length);
#endif
if (!make_user_info_map(&user_info,
user, workgroup,
machine,
lmhash, nthash,
plaintext_password,
neg_flags, True)) {
return ERROR_NT(NT_STATUS_NO_MEMORY);
}
SAFE_FREE(workgroup);
SAFE_FREE(machine);
nt_status = check_password(user_info, ntlmssp_auth_info, &server_info);
free_auth_info(&ntlmssp_auth_info);
free_user_info(&user_info);
data_blob_free(&lmhash);
data_blob_free(&nthash);
if (!NT_STATUS_IS_OK(nt_status)) {
SAFE_FREE(user);
return ERROR_NT(nt_status_squash(nt_status));
}
sess_vuid = register_vuid(server_info, user);
free_server_info(&server_info);
SAFE_FREE(user);
if (sess_vuid == -1) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
set_message(outbuf,4,0,True);
SSVAL(outbuf, smb_vwv3, 0);
add_signature(outbuf);
SSVAL(outbuf,smb_uid,sess_vuid);
SSVAL(inbuf,smb_uid,sess_vuid);
return chain_reply(inbuf,outbuf,length,bufsize);
}
/****************************************************************************
reply to a session setup spnego anonymous packet
****************************************************************************/
static int reply_spnego_anonymous(connection_struct *conn, char *inbuf, char *outbuf,
int length, int bufsize)
{
int sess_vuid;
auth_serversupplied_info *server_info = NULL;
NTSTATUS nt_status;
nt_status = check_guest_password(&server_info);
if (!NT_STATUS_IS_OK(nt_status)) {
return ERROR_NT(nt_status_squash(nt_status));
}
sess_vuid = register_vuid(server_info, lp_guestaccount());
free_server_info(&server_info);
if (sess_vuid == -1) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
set_message(outbuf,4,0,True);
SSVAL(outbuf, smb_vwv3, 0);
add_signature(outbuf);
SSVAL(outbuf,smb_uid,sess_vuid);
SSVAL(inbuf,smb_uid,sess_vuid);
return chain_reply(inbuf,outbuf,length,bufsize);
}
/****************************************************************************
reply to a session setup command
****************************************************************************/
static int reply_sesssetup_and_X_spnego(connection_struct *conn, char *inbuf,char *outbuf,
int length,int bufsize)
{
uint8 *p;
DATA_BLOB blob1;
int ret;
DEBUG(3,("Doing spnego session setup\n"));
if (global_client_caps == 0) {
global_client_caps = IVAL(inbuf,smb_vwv10);
}
p = (uint8 *)smb_buf(inbuf);
if (SVAL(inbuf, smb_vwv7) == 0) {
/* an anonymous request */
return reply_spnego_anonymous(conn, inbuf, outbuf, length, bufsize);
}
/* pull the spnego blob */
blob1 = data_blob(p, SVAL(inbuf, smb_vwv7));
#if 0
file_save("negotiate.dat", blob1.data, blob1.length);
#endif
if (blob1.data[0] == ASN1_APPLICATION(0)) {
/* its a negTokenTarg packet */
ret = reply_spnego_negotiate(conn, inbuf, outbuf, length, bufsize, blob1);
data_blob_free(&blob1);
return ret;
}
if (blob1.data[0] == ASN1_CONTEXT(1)) {
/* its a auth packet */
ret = reply_spnego_auth(conn, inbuf, outbuf, length, bufsize, blob1);
data_blob_free(&blob1);
return ret;
}
/* what sort of packet is this? */
DEBUG(1,("Unknown packet in reply_sesssetup_and_X_spnego\n"));
data_blob_free(&blob1);
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
/****************************************************************************
reply to a session setup command
****************************************************************************/
int reply_sesssetup_and_X(connection_struct *conn, char *inbuf,char *outbuf,
int length,int bufsize)
{
int sess_vuid;
int smb_bufsize;
DATA_BLOB lm_resp;
DATA_BLOB nt_resp;
DATA_BLOB plaintext_password;
pstring user;
pstring sub_user; /* Sainitised username for substituion */
fstring domain;
fstring native_os;
fstring native_lanman;
static BOOL done_sesssetup = False;
extern BOOL global_encrypted_passwords_negotiated;
extern BOOL global_spnego_negotiated;
extern int Protocol;
extern fstring remote_machine;
extern userdom_struct current_user_info;
extern int max_send;
auth_usersupplied_info *user_info = NULL;
extern auth_authsupplied_info *negprot_global_auth_info;
auth_serversupplied_info *server_info = NULL;
NTSTATUS nt_status;
BOOL doencrypt = global_encrypted_passwords_negotiated;
START_PROFILE(SMBsesssetupX);
ZERO_STRUCT(lm_resp);
ZERO_STRUCT(nt_resp);
ZERO_STRUCT(plaintext_password);
DEBUG(3,("wct=%d flg2=0x%x\n", CVAL(inbuf, smb_wct), SVAL(inbuf, smb_flg2)));
/* a SPNEGO session setup has 12 command words, whereas a normal
NT1 session setup has 13. See the cifs spec. */
if (CVAL(inbuf, smb_wct) == 12 &&
(SVAL(inbuf, smb_flg2) & FLAGS2_EXTENDED_SECURITY)) {
if (!global_spnego_negotiated) {
DEBUG(0,("reply_sesssetup_and_X: Rejecting attempt at SPNEGO session setup when it was not negoitiated.\n"));
return ERROR_NT(NT_STATUS_UNSUCCESSFUL);
}
return reply_sesssetup_and_X_spnego(conn, inbuf, outbuf, length, bufsize);
}
smb_bufsize = SVAL(inbuf,smb_vwv2);
if (Protocol < PROTOCOL_NT1) {
uint16 passlen1 = SVAL(inbuf,smb_vwv7);
if (passlen1 > MAX_PASS_LEN) {
return ERROR_DOS(ERRDOS,ERRbuftoosmall);
}
if (doencrypt) {
lm_resp = data_blob(smb_buf(inbuf), passlen1);
} else {
plaintext_password = data_blob(smb_buf(inbuf), passlen1+1);
/* Ensure null termination */
plaintext_password.data[passlen1] = 0;
}
srvstr_pull(inbuf, user, smb_buf(inbuf)+passlen1, sizeof(user), -1, STR_TERMINATE);
*domain = 0;
} else {
uint16 passlen1 = SVAL(inbuf,smb_vwv7);
uint16 passlen2 = SVAL(inbuf,smb_vwv8);
enum remote_arch_types ra_type = get_remote_arch();
char *p = smb_buf(inbuf);
if(global_client_caps == 0)
global_client_caps = IVAL(inbuf,smb_vwv11);
/* client_caps is used as final determination if client is NT or Win95.
This is needed to return the correct error codes in some
circumstances.
*/
if(ra_type == RA_WINNT || ra_type == RA_WIN2K || ra_type == RA_WIN95) {
if(!(global_client_caps & (CAP_NT_SMBS | CAP_STATUS32))) {
set_remote_arch( RA_WIN95);
}
}
if (passlen1 > MAX_PASS_LEN) {
return ERROR_DOS(ERRDOS,ERRbuftoosmall);
}
passlen1 = MIN(passlen1, MAX_PASS_LEN);
passlen2 = MIN(passlen2, MAX_PASS_LEN);
if (!doencrypt) {
/* both Win95 and WinNT stuff up the password lengths for
non-encrypting systems. Uggh.
if passlen1==24 its a win95 system, and its setting the
password length incorrectly. Luckily it still works with the
default code because Win95 will null terminate the password
anyway
if passlen1>0 and passlen2>0 then maybe its a NT box and its
setting passlen2 to some random value which really stuffs
things up. we need to fix that one. */
if (passlen1 > 0 && passlen2 > 0 && passlen2 != 24 && passlen2 != 1)
passlen2 = 0;
}
/* Save the lanman2 password and the NT md4 password. */
if ((doencrypt) && (passlen1 != 0) && (passlen1 != 24)) {
doencrypt = False;
}
if (doencrypt) {
lm_resp = data_blob(p, passlen1);
nt_resp = data_blob(p+passlen1, passlen2);
} else {
plaintext_password = data_blob(p, passlen1+1);
/* Ensure null termination */
plaintext_password.data[passlen1] = 0;
}
p += passlen1 + passlen2;
p += srvstr_pull(inbuf, user, p, sizeof(user), -1,
STR_TERMINATE);
p += srvstr_pull(inbuf, domain, p, sizeof(domain),
-1, STR_TERMINATE);
p += srvstr_pull(inbuf, native_os, p, sizeof(native_os),
-1, STR_TERMINATE);
p += srvstr_pull(inbuf, native_lanman, p, sizeof(native_lanman),
-1, STR_TERMINATE);
DEBUG(3,("Domain=[%s] NativeOS=[%s] NativeLanMan=[%s]\n",
domain,native_os,native_lanman));
}
/* don't allow for weird usernames or domains */
alpha_strcpy(user, user, ". _-$", sizeof(user));
alpha_strcpy(domain, domain, ". _-", sizeof(domain));
if (strstr(user, "..") || strstr(domain,"..")) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
DEBUG(3,("sesssetupX:name=[%s]\\[%s]@[%s]\n", domain, user, remote_machine));
if (*user) {
if (global_spnego_negotiated) {
DEBUG(0,("reply_sesssetup_and_X: Rejecting attempt at 'normal' session setup after negotiating spnego.\n"));
return ERROR_NT(NT_STATUS_UNSUCCESSFUL);
}
}
if (*user) {
pstrcpy(sub_user, user);
} else {
pstrcpy(sub_user, lp_guestaccount());
}
pstrcpy(current_user_info.smb_name,sub_user);
reload_services(True);
if (lp_security() == SEC_SHARE) {
/* in share level we should ignore any passwords */
data_blob_free(&lm_resp);
data_blob_free(&nt_resp);
data_blob_clear_free(&plaintext_password);
map_username(sub_user);
add_session_user(sub_user);
/* Then force it to null for the benfit of the code below */
*user = 0;
}
if (!*user) {
nt_status = check_guest_password(&server_info);
} else if (doencrypt) {
if (!make_user_info_for_reply_enc(&user_info,
user, domain,
lm_resp, nt_resp,
plaintext_password)) {
return ERROR_NT(NT_STATUS_NO_MEMORY);
}
nt_status = check_password(user_info, negprot_global_auth_info, &server_info);
} else {
auth_authsupplied_info *plaintext_auth_info = NULL;
DATA_BLOB chal;
if (!make_auth_info_subsystem(&plaintext_auth_info)) {
return ERROR_NT(NT_STATUS_NO_MEMORY);
}
chal = auth_get_challenge(plaintext_auth_info);
if (!make_user_info_for_reply(&user_info,
user, domain, chal.data,
plaintext_password)) {
return ERROR_NT(NT_STATUS_NO_MEMORY);
}
nt_status = check_password(user_info, plaintext_auth_info, &server_info);
data_blob_free(&chal);
free_auth_info(&plaintext_auth_info);
}
free_user_info(&user_info);
data_blob_free(&lm_resp);
data_blob_free(&nt_resp);
data_blob_clear_free(&plaintext_password);
if (!NT_STATUS_IS_OK(nt_status)) {
if NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_SUCH_USER) {
if ((lp_map_to_guest() == MAP_TO_GUEST_ON_BAD_USER) ||
(lp_map_to_guest() == MAP_TO_GUEST_ON_BAD_PASSWORD)) {
DEBUG(3,("No such user %s [%s] - using guest account\n",user, domain));
make_server_info_guest(&server_info);
nt_status = NT_STATUS_OK;
}
} else if NT_STATUS_EQUAL(nt_status, NT_STATUS_WRONG_PASSWORD) {
if (lp_map_to_guest() == MAP_TO_GUEST_ON_BAD_PASSWORD) {
DEBUG(3,("Registered username %s for guest access\n",user));
make_server_info_guest(&server_info);
nt_status = NT_STATUS_OK;
}
}
}
if (!NT_STATUS_IS_OK(nt_status)) {
return ERROR_NT(nt_status_squash(nt_status));
}
/* it's ok - setup a reply */
if (Protocol < PROTOCOL_NT1) {
set_message(outbuf,3,0,True);
} else {
set_message(outbuf,3,0,True);
add_signature(outbuf);
/* perhaps grab OS version here?? */
}
if (server_info->guest) {
SSVAL(outbuf,smb_vwv2,1);
} else {
const char *home_dir = pdb_get_homedir(server_info->sam_account);
const char *username = pdb_get_username(server_info->sam_account);
if ((home_dir && *home_dir)
&& (lp_servicenumber(username) < 0)) {
add_home_service(username, home_dir);
}
}
/* register the name and uid as being validated, so further connections
to a uid can get through without a password, on the same VC */
sess_vuid = register_vuid(server_info, sub_user);
free_server_info(&server_info);
if (sess_vuid == -1) {
return ERROR_NT(NT_STATUS_LOGON_FAILURE);
}
SSVAL(outbuf,smb_uid,sess_vuid);
SSVAL(inbuf,smb_uid,sess_vuid);
if (!done_sesssetup)
max_send = MIN(max_send,smb_bufsize);
done_sesssetup = True;
END_PROFILE(SMBsesssetupX);
return chain_reply(inbuf,outbuf,length,bufsize);
}