OpenWrt – Rev 1
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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
*/