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Add a new implementation of security=server.

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This is not intended for general use, and will not be easily exposed
(if I have anything to do with it), but should allow the CIFS proxy to
re-use the connection.

A work in progress.

Andrew Bartlett
(This used to be commit a1e60ebc6d)
This commit is contained in:
Andrew Bartlett 2008-05-05 13:21:18 +10:00
parent fe7d460671
commit 2c95244f11
3 changed files with 216 additions and 355 deletions
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1
source4/auth/auth.c
View File

@ -521,6 +521,7 @@ _PUBLIC_ NTSTATUS auth_init(void)
extern NTSTATUS auth_anonymous_init(void);
extern NTSTATUS auth_unix_init(void);
extern NTSTATUS auth_sam_init(void);
extern NTSTATUS auth_server_init(void);
init_module_fn static_init[] = { STATIC_auth_MODULES };

558
source4/auth/auth_server.c
View File

@ -1,9 +1,10 @@
/*
Unix SMB/CIFS implementation.
Authenticate to a remote server
Copyright (C) Andrew Tridgell 1992-1998
Copyright (C) Andrew Bartlett 2001
Authenticate by using a remote server
Copyright (C) Andrew Bartlett 2001-2002, 2008
Copyright (C) Jelmer Vernooij 2002
Copyright (C) Stefan Metzmacher 2005
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 3 of the License, or
@ -19,359 +20,206 @@
*/
#include "includes.h"
#include "auth/auth.h"
#include "auth/auth_proto.h"
#include "auth/credentials/credentials.h"
#include "libcli/security/security.h"
#include "librpc/gen_ndr/ndr_samr.h"
#include "libcli/smb_composite/smb_composite.h"
#include "param/param.h"
#include "libcli/resolve/resolve.h"
/****************************************************************************
Support for server level security.
****************************************************************************/
/* This version of 'security=server' rewirtten from scratch for Samba4
* libraries in 2008 */
static struct smbcli_state *server_cryptkey(TALLOC_CTX *mem_ctx, bool unicode, int maxprotocol, struct resolve_context *resolve_ctx)
static NTSTATUS server_want_check(struct auth_method_context *ctx,
TALLOC_CTX *mem_ctx,
const struct auth_usersupplied_info *user_info)
{
struct smbcli_state *cli = NULL;
fstring desthost;
struct in_addr dest_ip;
const char *p;
char *pserver;
bool connected_ok = false;
if (!(cli = smbcli_initialise(cli)))
return NULL;
/* security = server just can't function with spnego */
cli->use_spnego = false;
pserver = talloc_strdup(mem_ctx, lp_passwordserver());
p = pserver;
while(next_token( &p, desthost, LIST_SEP, sizeof(desthost))) {
strupper(desthost);
if(!resolve_name(resolve_ctx, desthost, &dest_ip, 0x20)) {
DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
continue;
}
if (ismyip(dest_ip)) {
DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
continue;
}
/* we use a mutex to prevent two connections at once - when a
Win2k PDC get two connections where one hasn't completed a
session setup yet it will send a TCP reset to the first
connection (tridge) */
if (!grab_server_mutex(desthost)) {
return NULL;
}
if (smbcli_connect(cli, desthost, &dest_ip)) {
DEBUG(3,("connected to password server %s\n",desthost));
connected_ok = true;
break;
}
}
if (!connected_ok) {
release_server_mutex();
DEBUG(0,("password server not available\n"));
talloc_free(cli);
return NULL;
}
if (!attempt_netbios_session_request(cli, lp_netbios_name(),
desthost, &dest_ip)) {
release_server_mutex();
DEBUG(1,("password server fails session request\n"));
talloc_free(cli);
return NULL;
}
if (strequal(desthost,myhostname(mem_ctx))) {
exit_server("Password server loop!");
}
DEBUG(3,("got session\n"));
if (!smbcli_negprot(cli, unicode, maxprotocol)) {
DEBUG(1,("%s rejected the negprot\n",desthost));
release_server_mutex();
talloc_free(cli);
return NULL;
}
if (cli->protocol < PROTOCOL_LANMAN2 ||
!(cli->sec_mode & NEGOTIATE_SECURITY_USER_LEVEL)) {
DEBUG(1,("%s isn't in user level security mode\n",desthost));
release_server_mutex();
talloc_free(cli);
return NULL;
}
/* Get the first session setup done quickly, to avoid silly
Win2k bugs. (The next connection to the server will kill
this one...
*/
if (!smbcli_session_setup(cli, "", "", 0, "", 0,
"")) {
DEBUG(0,("%s rejected the initial session setup (%s)\n",
desthost, smbcli_errstr(cli)));
release_server_mutex();
talloc_free(cli);
return NULL;
}
release_server_mutex();
DEBUG(3,("password server OK\n"));
return cli;
}
/****************************************************************************
Clean up our allocated cli.
****************************************************************************/
static void free_server_private_data(void **private_data_pointer)
{
struct smbcli_state **cli = (struct smbcli_state **)private_data_pointer;
if (*cli && (*cli)->initialised) {
talloc_free(*cli);
}
}
/****************************************************************************
Get the challenge out of a password server.
****************************************************************************/
static DATA_BLOB auth_get_challenge_server(const struct auth_context *auth_context,
void **my_private_data,
TALLOC_CTX *mem_ctx)
{
struct smbcli_state *cli = server_cryptkey(mem_ctx, lp_cli_maxprotocol(auth_context->lp_ctx));
if (cli) {
DEBUG(3,("using password server validation\n"));
if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
/* We can't work with unencrypted password servers
unless 'encrypt passwords = no' */
DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
/* However, it is still a perfectly fine connection
to pass that unencrypted password over */
*my_private_data = (void *)cli;
return data_blob(NULL, 0);
} else if (cli->secblob.length < 8) {
/* We can't do much if we don't get a full challenge */
DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
talloc_free(cli);
return data_blob(NULL, 0);
}
*my_private_data = (void *)cli;
/* The return must be allocated on the caller's mem_ctx, as our own will be
destoyed just after the call. */
return data_blob_talloc(auth_context->mem_ctx, cli->secblob.data,8);
} else {
return data_blob(NULL, 0);
}
}
/****************************************************************************
Check for a valid username and password in security=server mode.
- Validate a password with the password server.
****************************************************************************/
static NTSTATUS check_smbserver_security(const struct auth_context *auth_context,
void *my_private_data,
TALLOC_CTX *mem_ctx,
const auth_usersupplied_info *user_info,
auth_serversupplied_info **server_info)
{
struct smbcli_state *cli;
static uint8_t badpass[24];
static fstring baduser;
static bool tested_password_server = false;
static bool bad_password_server = false;
NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
bool locally_made_cli = false;
/*
* Check that the requested domain is not our own machine name.
* If it is, we should never check the PDC here, we use our own local
* password file.
*/
if (lp_is_myname(auth_context->lp_ctx, user_info->domain.str)) {
DEBUG(3,("check_smbserver_security: Requested domain was for this machine.\n"));
return NT_STATUS_LOGON_FAILURE;
}
cli = my_private_data;
if (cli) {
} else {
cli = server_cryptkey(mem_ctx, lp_unicode(auth_context->lp_ctx), lp_cli_maxprotocol(auth_context->lp_ctx), lp_resolve_context(auth_context->lp_ctx));
locally_made_cli = true;
}
if (!cli || !cli->initialised) {
DEBUG(1,("password server is not connected (cli not initilised)\n"));
return NT_STATUS_LOGON_FAILURE;
}
if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
if (user_info->encrypted) {
DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
return NT_STATUS_LOGON_FAILURE;
}
} else {
if (memcmp(cli->secblob.data, auth_context->challenge.data, 8) != 0) {
DEBUG(1,("the challenge that the password server (%s) supplied us is not the one we gave our client. This just can't work :-(\n", cli->desthost));
return NT_STATUS_LOGON_FAILURE;
}
}
if(badpass[0] == 0)
memset(badpass, 0x1f, sizeof(badpass));
if((user_info->nt_resp.length == sizeof(badpass)) &&
!memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
/*
* Very unlikely, our random bad password is the same as the users
* password.
*/
memset(badpass, badpass[0]+1, sizeof(badpass));
}
if(baduser[0] == 0) {
fstrcpy(baduser, INVALID_USER_PREFIX);
fstrcat(baduser, lp_netbios_name());
}
/*
* Attempt a session setup with a totally incorrect password.
* If this succeeds with the guest bit *NOT* set then the password
* server is broken and is not correctly setting the guest bit. We
* need to detect this as some versions of NT4.x are broken. JRA.
*/
/* I sure as hell hope that there aren't servers out there that take
* NTLMv2 and have this bug, as we don't test for that...
* - abartlet@samba.org
*/
if ((!tested_password_server) && (lp_paranoid_server_security())) {
if (smbcli_session_setup(cli, baduser, (char *)badpass, sizeof(badpass),
(char *)badpass, sizeof(badpass), user_info->domain.str)) {
/*
* We connected to the password server so we
* can say we've tested it.
*/
tested_password_server = true;
if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
DEBUG(0,("server_validate: password server %s allows users as non-guest \
with a bad password.\n", cli->desthost));
DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
use this machine as the password server.\n"));
smbcli_ulogoff(cli);
/*
* Password server has the bug.
*/
bad_password_server = true;
return NT_STATUS_LOGON_FAILURE;
}
smbcli_ulogoff(cli);
}
} else {
/*
* We have already tested the password server.
* Fail immediately if it has the bug.
*/
if(bad_password_server) {
DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
with a bad password.\n", cli->desthost));
DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
use this machine as the password server.\n"));
return NT_STATUS_LOGON_FAILURE;
}
}
/*
* Now we know the password server will correctly set the guest bit, or is
* not guest enabled, we can try with the real password.
*/
if (!user_info->encrypted) {
/* Plaintext available */
if (!smbcli_session_setup(cli, user_info->smb_name.str,
(char *)user_info->plaintext_password.data,
user_info->plaintext_password.length,
NULL, 0,
user_info->domain.str)) {
DEBUG(1,("password server %s rejected the password\n", cli->desthost));
/* Make this smbcli_nt_error() when the conversion is in */
nt_status = smbcli_nt_error(cli);
} else {
nt_status = NT_STATUS_OK;
}
} else {
if (!smbcli_session_setup(cli, user_info->smb_name.str,
(char *)user_info->lm_resp.data,
user_info->lm_resp.length,
(char *)user_info->nt_resp.data,
user_info->nt_resp.length,
user_info->domain.str)) {
DEBUG(1,("password server %s rejected the password\n", cli->desthost));
/* Make this smbcli_nt_error() when the conversion is in */
nt_status = smbcli_nt_error(cli);
} else {
nt_status = NT_STATUS_OK;
}
}
/* if logged in as guest then reject */
if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
nt_status = NT_STATUS_LOGON_FAILURE;
}
smbcli_ulogoff(cli);
if NT_STATUS_IS_OK(nt_status) {
struct passwd *pass = Get_Pwnam(user_info->internal_username.str);
if (pass) {
nt_status = make_server_info_pw(auth_context, server_info, pass);
} else {
nt_status = NT_STATUS_NO_SUCH_USER;
}
}
if (locally_made_cli) {
talloc_free(cli);
}
return(nt_status);
}
NTSTATUS auth_init_smbserver(struct auth_context *auth_context, const char* param, auth_methods **auth_method)
{
if (!make_auth_methods(auth_context, auth_method)) {
return NT_STATUS_NO_MEMORY;
}
(*auth_method)->name = "smbserver";
(*auth_method)->auth = check_smbserver_security;
(*auth_method)->get_chal = auth_get_challenge_server;
(*auth_method)->send_keepalive = send_server_keepalive;
(*auth_method)->free_private_data = free_server_private_data;
return NT_STATUS_OK;
}
/**
* The challenge from the target server, when operating in security=server
**/
static NTSTATUS server_get_challenge(struct auth_method_context *ctx, TALLOC_CTX *mem_ctx, DATA_BLOB *_blob)
{
struct smb_composite_connect io;
struct smbcli_options smb_options;
const char **host_list;
NTSTATUS status;
/* Make a connection to the target server, found by 'password server' in smb.conf */
lp_smbcli_options(ctx->auth_ctx->lp_ctx, &smb_options);
/* Make a negprot, WITHOUT SPNEGO, so we get a challenge nice an easy */
io.in.options.use_spnego = false;
/* Hope we don't get * (the default), as this won't work... */
host_list = lp_passwordserver(ctx->auth_ctx->lp_ctx);
if (!host_list) {
return NT_STATUS_INTERNAL_ERROR;
}
io.in.dest_host = host_list[0];
if (strequal(io.in.dest_host, "*")) {
return NT_STATUS_INTERNAL_ERROR;
}
io.in.dest_ports = lp_smb_ports(ctx->auth_ctx->lp_ctx);
io.in.called_name = strupper_talloc(mem_ctx, io.in.dest_host);
/* We don't want to get as far as the session setup */
io.in.credentials = NULL;
io.in.service = NULL;
io.in.workgroup = ""; /* only used with SPNEGO, disabled above */
io.in.options = smb_options;
status = smb_composite_connect(&io, mem_ctx, lp_resolve_context(ctx->auth_ctx->lp_ctx),
ctx->auth_ctx->event_ctx);
if (!NT_STATUS_IS_OK(status)) {
*_blob = io.out.tree->session->transport->negotiate.secblob;
ctx->private_data = talloc_steal(ctx, io.out.tree->session);
}
return NT_STATUS_OK;
}
/**
* Return an error based on username
*
* This function allows the testing of obsure errors, as well as the generation
* of NT_STATUS -> DOS error mapping tables.
*
* This module is of no value to end-users.
*
* The password is ignored.
*
* @return An NTSTATUS value based on the username
**/
static NTSTATUS server_check_password(struct auth_method_context *ctx,
TALLOC_CTX *mem_ctx,
const struct auth_usersupplied_info *user_info,
struct auth_serversupplied_info **_server_info)
{
NTSTATUS nt_status;
struct auth_serversupplied_info *server_info;
struct cli_credentials *creds;
const char *user;
struct smb_composite_sesssetup session_setup;
struct smbcli_session *session = talloc_get_type(ctx->private_data, struct smbcli_session);
creds = cli_credentials_init(mem_ctx);
NT_STATUS_HAVE_NO_MEMORY(creds);
cli_credentials_set_username(creds, user_info->client.account_name, CRED_SPECIFIED);
cli_credentials_set_domain(creds, user_info->client.domain_name, CRED_SPECIFIED);
switch (user_info->password_state) {
case AUTH_PASSWORD_PLAIN:
cli_credentials_set_password(creds, user_info->password.plaintext,
CRED_SPECIFIED);
break;
case AUTH_PASSWORD_HASH:
cli_credentials_set_nt_hash(creds, user_info->password.hash.nt,
CRED_SPECIFIED);
break;
case AUTH_PASSWORD_RESPONSE:
cli_credentials_set_ntlm_response(creds, &user_info->password.response.lanman, &user_info->password.response.nt, CRED_SPECIFIED);
break;
}
session_setup.in.sesskey = session->transport->negotiate.sesskey;
session_setup.in.capabilities = session->transport->negotiate.capabilities;
session_setup.in.credentials = creds;
session_setup.in.workgroup = ""; /* Only used with SPNEGO, which we are not doing */
/* Check password with remove server - this should be async some day */
nt_status = smb_composite_sesssetup(session, &session_setup);
if (!NT_STATUS_IS_OK(nt_status)) {
return nt_status;
}
server_info = talloc(mem_ctx, struct auth_serversupplied_info);
NT_STATUS_HAVE_NO_MEMORY(server_info);
server_info->account_sid = dom_sid_parse_talloc(server_info, SID_NT_ANONYMOUS);
NT_STATUS_HAVE_NO_MEMORY(server_info->account_sid);
/* is this correct? */
server_info->primary_group_sid = dom_sid_parse_talloc(server_info, SID_BUILTIN_GUESTS);
NT_STATUS_HAVE_NO_MEMORY(server_info->primary_group_sid);
server_info->n_domain_groups = 0;
server_info->domain_groups = NULL;
/* annoying, but the Anonymous really does have a session key,
and it is all zeros! */
server_info->user_session_key = data_blob(NULL, 0);
server_info->lm_session_key = data_blob(NULL, 0);
server_info->account_name = talloc_strdup(server_info, user_info->client.account_name);
NT_STATUS_HAVE_NO_MEMORY(server_info->account_name);
server_info->domain_name = talloc_strdup(server_info, user_info->client.domain_name);
NT_STATUS_HAVE_NO_MEMORY(server_info->domain_name);
server_info->full_name = NULL;
server_info->logon_script = talloc_strdup(server_info, "");
NT_STATUS_HAVE_NO_MEMORY(server_info->logon_script);
server_info->profile_path = talloc_strdup(server_info, "");
NT_STATUS_HAVE_NO_MEMORY(server_info->profile_path);
server_info->home_directory = talloc_strdup(server_info, "");
NT_STATUS_HAVE_NO_MEMORY(server_info->home_directory);
server_info->home_drive = talloc_strdup(server_info, "");
NT_STATUS_HAVE_NO_MEMORY(server_info->home_drive);
server_info->last_logon = 0;
server_info->last_logoff = 0;
server_info->acct_expiry = 0;
server_info->last_password_change = 0;
server_info->allow_password_change = 0;
server_info->force_password_change = 0;
server_info->logon_count = 0;
server_info->bad_password_count = 0;
server_info->acct_flags = ACB_NORMAL;
server_info->authenticated = false;
*_server_info = server_info;
return nt_status;
}
static const struct auth_operations server_auth_ops = {
.name = "server",
.get_challenge = server_get_challenge,
.want_check = server_want_check,
.check_password = server_check_password
};
_PUBLIC_ NTSTATUS auth_server_init(void)
{
NTSTATUS ret;
ret = auth_register(&server_auth_ops);
if (!NT_STATUS_IS_OK(ret)) {
DEBUG(0,("Failed to register 'server' auth backend!\n"));
return ret;
}
return ret;
}

12
source4/auth/config.mk
View File

@ -54,6 +54,18 @@ SUBSYSTEM = auth
auth_anonymous_OBJ_FILES = $(addprefix auth/, auth_anonymous.o)
#######################
# Start MODULE auth_anonymous
[MODULE::auth_server]
INIT_FUNCTION = auth_server_init
SUBSYSTEM = auth
PRIVATE_DEPENDENCIES = LIBSAMBA-UTIL LIBCLI_SMB
OUTPUT_TYPE = SHARED_LIBRARY
# End MODULE auth_server
#######################
auth_server_OBJ_FILES = $(addprefix auth/, auth_server.o)
#######################
# Start MODULE auth_winbind
[MODULE::auth_winbind]