packages/samba
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
samba/backport-0021-CVE-2022-38023.patch

178 lines
8.0 KiB
Diff
Raw Blame History

From 7f5e36250fa7121435f315cffa7b7059d3fe40a8 Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <metze@samba.org>
Date: Fri, 25 Nov 2022 14:02:11 +0100
Subject: [PATCH 21/30] CVE-2022-38023 docs-xml/smbdotconf: document "server
reject md5 schannel:COMPUTERACCOUNT"
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15240
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
(cherry picked from commit 2ad302b42254e3c2800aaf11669fe2e6d55fa8a1)
Conflict: NA
Reference: https://attachments.samba.org/attachment.cgi?id=17692
---
docs-xml/smbdotconf/logon/allownt4crypto.xml | 13 ++-
.../smbdotconf/logon/rejectmd5clients.xml | 96 ++++++++++++++++++-
2 files changed, 103 insertions(+), 6 deletions(-)
diff --git a/docs-xml/smbdotconf/logon/allownt4crypto.xml b/docs-xml/smbdotconf/logon/allownt4crypto.xml
index bbd03a42db74..ee63e6cc2453 100644
--- a/docs-xml/smbdotconf/logon/allownt4crypto.xml
+++ b/docs-xml/smbdotconf/logon/allownt4crypto.xml
@@ -45,7 +45,9 @@
in order to collect the explicit
'<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT">yes</smbconfoption>' options.</para>
- <para>This option is over-ridden by the '<smbconfoption name="reject md5 clients">yes</smbconfoption>' option.</para>
+ <para>This option is over-ridden by the effective value of 'yes' from
+ the '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT"/>'
+ and/or '<smbconfoption name="reject md5 clients"/>' options.</para>
</description>
<value type="default">no</value>
@@ -85,12 +87,19 @@
<para>This option overrides the <smbconfoption name="allow nt4 crypto"/> option.</para>
- <para>This option is over-ridden by the '<smbconfoption name="reject md5 clients">yes</smbconfoption>' option.</para>
+ <para>This option is over-ridden by the effective value of 'yes' from
+ the '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT"/>'
+ and/or '<smbconfoption name="reject md5 clients"/>' options.</para>
+ <para>Which means '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT">yes</smbconfoption>'
+ is only useful in combination with '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT">no</smbconfoption>'</para>
<programlisting>
allow nt4 crypto:LEGACYCOMPUTER1$ = yes
+ server reject md5 schannel:LEGACYCOMPUTER1$ = no
allow nt4 crypto:NASBOX$ = yes
+ server reject md5 schannel:NASBOX$ = no
allow nt4 crypto:LEGACYCOMPUTER2$ = yes
+ server reject md5 schannel:LEGACYCOMPUTER2$ = no
</programlisting>
</description>
diff --git a/docs-xml/smbdotconf/logon/rejectmd5clients.xml b/docs-xml/smbdotconf/logon/rejectmd5clients.xml
index edcbe02e99a3..fe7701d92772 100644
--- a/docs-xml/smbdotconf/logon/rejectmd5clients.xml
+++ b/docs-xml/smbdotconf/logon/rejectmd5clients.xml
@@ -1,8 +1,15 @@
<samba:parameter name="reject md5 clients"
context="G"
type="boolean"
+ deprecated="1"
xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
<description>
+ <para>
+ This option is deprecated and will be removed in a future release,
+ as it is a security problem if not set to "yes" (which will be
+ the hardcoded behavior in the future).
+ </para>
+
<para>This option controls whether the netlogon server (currently
only in 'active directory domain controller' mode), will
reject clients which does not support NETLOGON_NEG_SUPPORTS_AES.</para>
@@ -10,13 +17,94 @@
<para>Support for NETLOGON_NEG_SUPPORTS_AES was added in Windows
starting with Server 2008R2 and Windows 7, it's available in Samba
starting with 4.0, however third party domain members like NetApp ONTAP
- still uses RC4 (HMAC-MD5), see https://www.samba.org/samba/security/CVE-2022-38023.html for more details.</para>
+ still uses RC4 (HMAC-MD5), see
+ <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">https://www.samba.org/samba/security/CVE-2022-38023.html</ulink>
+ for more details.
+ </para>
+
+ <para>The default changed from 'no' to 'yes', with the patches for
+ <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">CVE-2022-38023</ulink>
+ see <ulink url="https://bugzilla.samba.org/show_bug.cgi?id=15240">https://bugzilla.samba.org/show_bug.cgi?id=15240</ulink>.
+ </para>
+
+ <para><emphasis>Avoid using this option!</emphasis> Use an explicit per machine account
+ '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT"/>' instead!
+ Which is available with the patches for
+ <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">CVE-2022-38023</ulink>
+ see <ulink url="https://bugzilla.samba.org/show_bug.cgi?id=15240">https://bugzilla.samba.org/show_bug.cgi?id=15240</ulink>.
+ </para>
- <para>The default changed from 'no' to 'yes', with the patches for CVE-2022-38023,
- see https://bugzilla.samba.org/show_bug.cgi?id=15240</para>
+ <para>
+ Samba will log an error in the log files at log level 0
+ if legacy a client is rejected or allowed without an explicit,
+ '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT">no</smbconfoption>' option
+ for the client. The message will indicate
+ the explicit '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT">no</smbconfoption>'
+ line to be added, if the legacy client software requires it. (The log level can be adjusted with
+ '<smbconfoption name="CVE_2022_38023:error_debug_level">1</smbconfoption>'
+ in order to complain only at a higher log level).
+ </para>
- <para>This option overrides the 'allow nt4 crypto' option.</para>
+ <para>This allows admins to use "no" only for a short grace period,
+ in order to collect the explicit
+ '<smbconfoption name="server reject md5 schannel:COMPUTERACCOUNT">no</smbconfoption>' options.</para>
+
+ <para>When set to 'yes' this option overrides the
+ '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT"/>' and
+ '<smbconfoption name="allow nt4 crypto"/>' options and implies
+ '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT">no</smbconfoption>'.
+ </para>
</description>
<value type="default">yes</value>
</samba:parameter>
+
+<samba:parameter name="server reject md5 schannel:COMPUTERACCOUNT"
+ context="G"
+ type="string"
+ xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
+<description>
+
+ <para>If you still have legacy domain members or trusted domains,
+ which required "reject md5 clients = no" before,
+ it is possible to specify an explicit exception per computer account
+ by setting 'server reject md5 schannel:COMPUTERACCOUNT = no'.
+ Note that COMPUTERACCOUNT has to be the sAMAccountName value of
+ the computer account (including the trailing '$' sign).
+ </para>
+
+ <para>
+ Samba will log a complaint in the log files at log level 0
+ about the security problem if the option is set to "no",
+ but the related computer does not require it.
+ (The log level can be adjusted with
+ '<smbconfoption name="CVE_2022_38023:warn_about_unused_debug_level">1</smbconfoption>'
+ in order to complain only at a higher log level).
+ </para>
+
+ <para>
+ Samba will log a warning in the log files at log level 5
+ if a setting is still needed for the specified computer account.
+ </para>
+
+ <para>
+ See <ulink url="https://www.samba.org/samba/security/CVE-2022-38023.html">CVE-2022-38023</ulink>,
+ <ulink url="https://bugzilla.samba.org/show_bug.cgi?id=15240">https://bugzilla.samba.org/show_bug.cgi?id=15240</ulink>.
+ </para>
+
+ <para>This option overrides the <smbconfoption name="reject md5 clients"/> option.</para>
+
+ <para>When set to 'yes' this option overrides the
+ '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT"/>' and
+ '<smbconfoption name="allow nt4 crypto"/>' options and implies
+ '<smbconfoption name="allow nt4 crypto:COMPUTERACCOUNT">no</smbconfoption>'.
+ </para>
+
+ <programlisting>
+ server reject md5 schannel:LEGACYCOMPUTER1$ = no
+ server reject md5 schannel:NASBOX$ = no
+ server reject md5 schannel:LEGACYCOMPUTER2$ = no
+ </programlisting>
+</description>
+
+</samba:parameter>
--
2.34.1
Reference in New Issue View Git Blame Copy Permalink