1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
|
From 513bd34e4523e49e742487be32a7239111486a12 Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <metze@samba.org>
Date: Sat, 27 Feb 2016 03:43:58 +0100
Subject: [PATCH 1/4] CVE-2016-2115: docs-xml: add "client ipc signing" option
BUG: https://bugzilla.samba.org/show_bug.cgi?id=11756
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
---
docs-xml/smbdotconf/security/clientipcsigning.xml | 23 +++++++++++++++++++++++
docs-xml/smbdotconf/security/clientsigning.xml | 3 +++
source3/include/proto.h | 1 +
source3/param/loadparm.c | 12 ++++++++++++
4 files changed, 39 insertions(+)
create mode 100644 docs-xml/smbdotconf/security/clientipcsigning.xml
--- /dev/null
+++ b/docs-xml/smbdotconf/security/clientipcsigning.xml
@@ -0,0 +1,23 @@
+<samba:parameter name="client ipc signing"
+ context="G"
+ type="enum"
+ enumlist="enum_smb_signing_vals"
+ xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
+<description>
+ <para>This controls whether the client is allowed or required to use SMB signing for IPC$
+ connections as DCERPC transport inside of winbind. Possible values
+ are <emphasis>auto</emphasis>, <emphasis>mandatory</emphasis>
+ and <emphasis>disabled</emphasis>.
+ </para>
+
+ <para>When set to auto, SMB signing is offered, but not enforced and if set
+ to disabled, SMB signing is not offered either.</para>
+
+ <para>Connections from winbindd to Active Directory Domain Controllers
+ always enforce signing.</para>
+</description>
+
+<related>client signing</related>
+
+<value type="default">mandatory</value>
+</samba:parameter>
--- a/docs-xml/smbdotconf/security/clientsigning.xml
+++ b/docs-xml/smbdotconf/security/clientsigning.xml
@@ -12,6 +12,9 @@
<para>When set to auto, SMB signing is offered, but not enforced.
When set to mandatory, SMB signing is required and if set
to disabled, SMB signing is not offered either.
+
+ <para>IPC$ connections for DCERPC e.g. in winbindd, are handled by the
+ <smbconfoption name="client ipc signing"/> option.</para>
</para>
</description>
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -1690,9 +1690,11 @@ int lp_winbind_cache_time(void);
int lp_winbind_reconnect_delay(void);
int lp_winbind_max_clients(void);
const char **lp_winbind_nss_info(void);
+bool lp_winbind_sealed_pipes(void);
int lp_algorithmic_rid_base(void);
int lp_name_cache_timeout(void);
int lp_client_signing(void);
+int lp_client_ipc_signing(void);
int lp_server_signing(void);
int lp_client_ldap_sasl_wrapping(void);
char *lp_parm_talloc_string(int snum, const char *type, const char *option, const char *def);
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -215,6 +215,7 @@ struct global {
int winbind_expand_groups;
bool bWinbindRefreshTickets;
bool bWinbindOfflineLogon;
+ bool bWinbindSealedPipes;
bool bWinbindNormalizeNames;
bool bWinbindRpcOnly;
bool bCreateKrb5Conf;
@@ -366,6 +367,7 @@ struct global {
int restrict_anonymous;
int name_cache_timeout;
int client_signing;
+ int client_ipc_signing;
int server_signing;
int client_ldap_sasl_wrapping;
int iUsershareMaxShares;
@@ -2319,6 +2321,15 @@ static struct parm_struct parm_table[] =
.flags = FLAG_ADVANCED,
},
{
+ .label = "client ipc signing",
+ .type = P_ENUM,
+ .p_class = P_GLOBAL,
+ .ptr = &Globals.client_ipc_signing,
+ .special = NULL,
+ .enum_list = enum_smb_signing_vals,
+ .flags = FLAG_ADVANCED,
+ },
+ {
.label = "server signing",
.type = P_ENUM,
.p_class = P_GLOBAL,
@@ -4765,6 +4776,15 @@ static struct parm_struct parm_table[] =
.flags = FLAG_ADVANCED,
},
{
+ .label = "winbind sealed pipes",
+ .type = P_BOOL,
+ .p_class = P_GLOBAL,
+ .ptr = &Globals.bWinbindSealedPipes,
+ .special = NULL,
+ .enum_list = NULL,
+ .flags = FLAG_ADVANCED,
+ },
+ {
.label = "winbind normalize names",
.type = P_BOOL,
.p_class = P_GLOBAL,
@@ -5458,6 +5478,7 @@ static void init_globals(bool reinit_glo
Globals.szWinbindNssInfo = str_list_make_v3(NULL, "template", NULL);
Globals.bWinbindRefreshTickets = False;
Globals.bWinbindOfflineLogon = False;
+ Globals.bWinbindSealedPipes = True;
Globals.iIdmapCacheTime = 86400 * 7; /* a week by default */
Globals.iIdmapNegativeCacheTime = 120; /* 2 minutes by default */
@@ -5470,6 +5491,7 @@ static void init_globals(bool reinit_glo
Globals.bClientUseSpnego = True;
Globals.client_signing = Auto;
+ Globals.client_ipc_signing = Required;
Globals.server_signing = False;
Globals.bDeferSharingViolations = True;
@@ -5736,6 +5758,7 @@ FN_GLOBAL_BOOL(lp_winbind_nested_groups,
FN_GLOBAL_INTEGER(lp_winbind_expand_groups, &Globals.winbind_expand_groups)
FN_GLOBAL_BOOL(lp_winbind_refresh_tickets, &Globals.bWinbindRefreshTickets)
FN_GLOBAL_BOOL(lp_winbind_offline_logon, &Globals.bWinbindOfflineLogon)
+FN_GLOBAL_BOOL(lp_winbind_sealed_pipes, &Globals.bWinbindSealedPipes)
FN_GLOBAL_BOOL(lp_winbind_normalize_names, &Globals.bWinbindNormalizeNames)
FN_GLOBAL_BOOL(lp_winbind_rpc_only, &Globals.bWinbindRpcOnly)
FN_GLOBAL_BOOL(lp_create_krb5_conf, &Globals.bCreateKrb5Conf)
@@ -6071,6 +6094,7 @@ FN_GLOBAL_LIST(lp_winbind_nss_info, &Glo
FN_GLOBAL_INTEGER(lp_algorithmic_rid_base, &Globals.AlgorithmicRidBase)
FN_GLOBAL_INTEGER(lp_name_cache_timeout, &Globals.name_cache_timeout)
FN_GLOBAL_INTEGER(lp_client_signing, &Globals.client_signing)
+FN_GLOBAL_INTEGER(lp_client_ipc_signing, &Globals.client_ipc_signing)
FN_GLOBAL_INTEGER(lp_server_signing, &Globals.server_signing)
FN_GLOBAL_INTEGER(lp_client_ldap_sasl_wrapping, &Globals.client_ldap_sasl_wrapping)
@@ -9700,6 +9724,20 @@ static bool lp_load_ex(const char *pszFn
lp_do_parameter(GLOBAL_SECTION_SNUM, "wins server", "127.0.0.1");
}
+ if (!lp_is_in_client()) {
+ switch (lp_client_ipc_signing()) {
+ case Required:
+ lp_set_cmdline("client signing", "mandatory");
+ break;
+ case Auto:
+ lp_set_cmdline("client signing", "auto");
+ break;
+ case False:
+ lp_set_cmdline("client signing", "disabled");
+ break;
+ }
+ }
+
init_iconv();
bAllowIncludeRegistry = true;
--- a/source3/rpc_server/spoolss/srv_spoolss_nt.c
+++ b/source3/rpc_server/spoolss/srv_spoolss_nt.c
@@ -2480,7 +2480,7 @@ static bool spoolss_connect_to_client(st
"", /* username */
"", /* domain */
"", /* password */
- 0, lp_client_signing());
+ 0, False);
if ( !NT_STATUS_IS_OK( ret ) ) {
DEBUG(2,("spoolss_connect_to_client: connection to [%s] failed!\n",
--- /dev/null
+++ b/docs-xml/smbdotconf/winbind/winbindsealedpipes.xml
@@ -0,0 +1,15 @@
+<samba:parameter name="winbind sealed pipes"
+ context="G"
+ type="boolean"
+ xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
+<description>
+ <para>This option controls whether any requests from winbindd to domain controllers
+ pipe will be sealed. Disabling sealing can be useful for debugging
+ purposes.</para>
+
+ <para>The behavior can be controlled per netbios domain
+ by using 'winbind sealed pipes:NETBIOSDOMAIN = no' as option.</para>
+</description>
+
+<value type="default">yes</value>
+</samba:parameter>
--- a/source3/winbindd/winbindd_cm.c
+++ b/source3/winbindd/winbindd_cm.c
@@ -2384,6 +2384,15 @@ NTSTATUS cm_connect_sam(struct winbindd_
TALLOC_FREE(conn->samr_pipe);
anonymous:
+ if (lp_winbind_sealed_pipes() && (IS_DC || domain->primary)) {
+ status = NT_STATUS_DOWNGRADE_DETECTED;
+ DEBUG(1, ("Unwilling to make SAMR connection to domain %s "
+ "without connection level security, "
+ "must set 'winbind sealed pipes = false' "
+ "to proceed: %s\n",
+ domain->name, nt_errstr(status)));
+ goto done;
+ }
/* Finally fall back to anonymous. */
status = cli_rpc_pipe_open_noauth(conn->cli, &ndr_table_samr.syntax_id,
@@ -2610,6 +2619,16 @@ NTSTATUS cm_connect_lsa(struct winbindd_
anonymous:
+ if (lp_winbind_sealed_pipes() && (IS_DC || domain->primary)) {
+ result = NT_STATUS_DOWNGRADE_DETECTED;
+ DEBUG(1, ("Unwilling to make LSA connection to domain %s "
+ "without connection level security, "
+ "must set 'winbind sealed pipes = false' "
+ "to proceed: %s\n",
+ domain->name, nt_errstr(result)));
+ goto done;
+ }
+
result = cli_rpc_pipe_open_noauth(conn->cli,
&ndr_table_lsarpc.syntax_id,
&conn->lsa_pipe);
@@ -2749,7 +2768,18 @@ NTSTATUS cm_connect_netlogon(struct winb
no_schannel:
if ((lp_client_schannel() == False) ||
- ((neg_flags & NETLOGON_NEG_SCHANNEL) == 0)) {
+ ((neg_flags & NETLOGON_NEG_SCHANNEL) == 0)) {
+ if (lp_winbind_sealed_pipes() && (IS_DC || domain->primary)) {
+ result = NT_STATUS_DOWNGRADE_DETECTED;
+ DEBUG(1, ("Unwilling to make connection to domain %s "
+ "without connection level security, "
+ "must set 'winbind sealed pipes = false' "
+ "to proceed: %s\n",
+ domain->name, nt_errstr(result)));
+ TALLOC_FREE(netlogon_pipe);
+ invalidate_cm_connection(conn);
+ return result;
+ }
/*
* NetSamLogonEx only works for schannel
*/
|
