From: Stefan Metzmacher <metze@samba.org>
Date: Sat, 27 Feb 2016 02:43:58 +0000 (+0100)
Subject: CVE-2016-2115: docs-xml: add "client ipc signing" option
X-Git-Tag: samba-4.2.10~135
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d5d1d63a73d47c3959de114cd40cfedea6ac788e;p=thirdparty%2Fsamba.git

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>
---

diff --git a/docs-xml/smbdotconf/security/clientipcsigning.xml b/docs-xml/smbdotconf/security/clientipcsigning.xml
new file mode 100644
index 00000000000..d976f2dc00e
--- /dev/null
+++ b/docs-xml/smbdotconf/security/clientipcsigning.xml
@@ -0,0 +1,35 @@
+<samba:parameter name="client ipc signing"
+                 context="G"
+                 type="enum"
+                 function="_client_ipc_signing"
+                 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. Possible values
+    are <emphasis>auto</emphasis>, <emphasis>mandatory</emphasis>
+    and <emphasis>disabled</emphasis>.
+    </para>
+
+    <para>The default value is the same as the effective value of
+    <smbconfoption name="client signing"/> if the effective value of
+    <smbconfoption name="client ipc min protocol"/> is
+    <constant>NT1</constant>. In any other case the default value is
+    <constant>mandatory</constant>.</para>
+
+    <para>Note that the default value will be changed to <constant>mandatory</constant>
+    in all cases for Samba 4.5</para>
+
+    <para>When the effective value of this option is <constant>mandatory</constant>, SMB signing is required.</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">default</value>
+</samba:parameter>
diff --git a/docs-xml/smbdotconf/security/clientsigning.xml b/docs-xml/smbdotconf/security/clientsigning.xml
index 3b5687f7691..354cc535248 100644
--- a/docs-xml/smbdotconf/security/clientsigning.xml
+++ b/docs-xml/smbdotconf/security/clientsigning.xml
@@ -9,14 +9,16 @@
     and <emphasis>disabled</emphasis>. 
     </para>
 
-    <para>When set to auto or default, SMB signing is offered, but not
-    enforced, except in winbindd, where it is enforced to Active
-    Directory Domain Controllers. </para>
+    <para>When set to auto or default, SMB signing is offered, but not enforced.</para>
 
     <para>When set to mandatory, SMB signing is required and if set
-	to disabled, SMB signing is not offered either.
-</para>
+    to disabled, SMB signing is not offered either.</para>
+
+    <para>IPC$ connections for DCERPC e.g. in winbindd, are handled by the
+    <smbconfoption name="client ipc signing"/> option.</para>
 </description>
 
+<related>client ipc signing</related>
+
 <value type="default">default</value>
 </samba:parameter>
diff --git a/lib/param/loadparm.c b/lib/param/loadparm.c
index 6fda6d6a737..13835f1a12b 100644
--- a/lib/param/loadparm.c
+++ b/lib/param/loadparm.c
@@ -2536,6 +2536,7 @@ struct loadparm_context *loadparm_init(TALLOC_CTX *mem_ctx)
 	lpcfg_do_global_parameter(lp_ctx, "template homedir", "/home/%D/%U");
 
 	lpcfg_do_global_parameter(lp_ctx, "client signing", "default");
+	lpcfg_do_global_parameter(lp_ctx, "client ipc signing", "default");
 	lpcfg_do_global_parameter(lp_ctx, "server signing", "default");
 
 	lpcfg_do_global_parameter(lp_ctx, "use spnego", "True");
@@ -3207,6 +3208,19 @@ int lpcfg_client_ipc_max_protocol(struct loadparm_context *lp_ctx)
 	return client_ipc_max_protocol;
 }
 
+int lpcfg_client_ipc_signing(struct loadparm_context *lp_ctx)
+{
+	int client_ipc_signing = lpcfg__client_ipc_signing(lp_ctx);
+	if (client_ipc_signing == SMB_SIGNING_DEFAULT) {
+		int ipc_min_protocol = lpcfg_client_ipc_min_protocol(lp_ctx);
+		if (ipc_min_protocol >= PROTOCOL_SMB2_02) {
+			return SMB_SIGNING_REQUIRED;
+		}
+		return lpcfg_client_signing(lp_ctx);
+	}
+	return client_ipc_signing;
+}
+
 bool lpcfg_server_signing_allowed(struct loadparm_context *lp_ctx, bool *mandatory)
 {
 	bool allowed = true;
diff --git a/source3/include/proto.h b/source3/include/proto.h
index a78d3506601..f6052026529 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -947,6 +947,7 @@ int lp_client_max_protocol(void);
 int lp_winbindd_max_protocol(void);
 int lp_client_ipc_min_protocol(void);
 int lp_client_ipc_max_protocol(void);
+int lp_client_ipc_signing(void);
 int lp_smb2_max_credits(void);
 int lp_cups_encrypt(void);
 bool lp_widelinks(int );
diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index 24c0141d7ca..1767488134a 100644
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -789,6 +789,7 @@ static void init_globals(struct loadparm_context *lp_ctx, bool reinit_globals)
 	Globals.client_use_spnego = true;
 
 	Globals.client_signing = SMB_SIGNING_DEFAULT;
+	Globals._client_ipc_signing = SMB_SIGNING_DEFAULT;
 	Globals.server_signing = SMB_SIGNING_DEFAULT;
 
 	Globals.defer_sharing_violations = true;
@@ -4366,6 +4367,19 @@ int lp_client_ipc_max_protocol(void)
 	return client_ipc_max_protocol;
 }
 
+int lp_client_ipc_signing(void)
+{
+	int client_ipc_signing = lp__client_ipc_signing();
+	if (client_ipc_signing == SMB_SIGNING_DEFAULT) {
+		int ipc_min_protocol = lp_client_ipc_min_protocol();
+		if (ipc_min_protocol >= PROTOCOL_SMB2_02) {
+			return SMB_SIGNING_REQUIRED;
+		}
+		return lp_client_signing();
+	}
+	return client_ipc_signing;
+}
+
 struct loadparm_global * get_globals(void)
 {
 	return &Globals;