From 8c87e39ca081a910f5833e1111a6e46f3239c4a4 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra@samba.org>
Date: Tue, 13 Sep 2011 17:03:46 -0700
Subject: [PATCH] Fix bug #8229 - git patch attached against 3.6.0-rc2 to fix 'widelinks' regression intro'd in 3.2

Add "allow insecure widelinks" to re-enable the ability (requested
by some sites) to have "widelinks = yes" and "unix extensions = yes".

Based on an original patch by Linda Walsh <samba@tlinx.org>
---
 .../smbdotconf/misc/allowinsecurewidelinks.xml     |   37 ++++++++++++++++++++
 docs-xml/smbdotconf/misc/widelinks.xml             |    4 ++
 docs-xml/smbdotconf/protocol/unixextensions.xml    |    4 ++
 source3/include/proto.h                            |    1 +
 source3/param/loadparm.c                           |   23 ++++++++++++-
 5 files changed, 68 insertions(+), 1 deletions(-)
 create mode 100644 docs-xml/smbdotconf/misc/allowinsecurewidelinks.xml

diff --git a/docs-xml/smbdotconf/misc/allowinsecurewidelinks.xml b/docs-xml/smbdotconf/misc/allowinsecurewidelinks.xml
new file mode 100644
index 0000000..a8a0991
--- /dev/null
+++ b/docs-xml/smbdotconf/misc/allowinsecurewidelinks.xml
@@ -0,0 +1,37 @@
+<samba:parameter name="allow insecure wide links"
+		context="G"
+		type="boolean"
+		xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
+<description>
+	<para>
+	In normal operation the option <smbconfoption name="wide links"/>
+	which allows the server to follow symlinks outside of a share path
+	is automatically disabled when <smbconfoption name="unix extensions"/>
+	are enabled on a Samba server. This is done for security purposes
+	to prevent UNIX clients creating symlinks to areas of the server
+	file system that the administrator does not wish to export.
+	</para>
+	<para>
+	Setting <smbconfoption name="allow insecure wide links"/> to
+	true disables the link between these two parameters, removing
+	this protection and allowing a site to configure
+	the server to follow symlinks (by setting <smbconfoption name="wide links"/>
+	to "true") even when <smbconfoption name="unix extensions"/>
+	is turned on.
+	</para>
+	<para>
+	If is not recommended to enable this option unless you
+	fully understand the implications of allowing the server to
+	follow symbolic links created by UNIX clients. For most
+	normal Samba configurations this would be considered a security
+	hole and setting this parameter is not recommended.
+	</para>
+	<para>
+	This option was added at the request of sites who had
+	deliberately set Samba up in this way and needed to continue
+	supporting this functionality without having to patch the
+	Samba code.
+	</para>
+</description>
+<value type="default">no</value>
+</samba:parameter>
diff --git a/docs-xml/smbdotconf/misc/widelinks.xml b/docs-xml/smbdotconf/misc/widelinks.xml
index 1c30bb7..da1374a 100644
--- a/docs-xml/smbdotconf/misc/widelinks.xml
+++ b/docs-xml/smbdotconf/misc/widelinks.xml
@@ -17,6 +17,10 @@
 	disabled (with a message in the log file) if the
 	<smbconfoption name="unix extensions"/> option is on.
 	</para>
+	<para>
+	See the parameter <smbconfoption name="allow insecure wide links"/>
+	if you wish to change this coupling between the two parameters.
+	</para>
 </description>
 
 <value type="default">no</value>
diff --git a/docs-xml/smbdotconf/protocol/unixextensions.xml b/docs-xml/smbdotconf/protocol/unixextensions.xml
index d816648..61a39cb 100644
--- a/docs-xml/smbdotconf/protocol/unixextensions.xml
+++ b/docs-xml/smbdotconf/protocol/unixextensions.xml
@@ -14,6 +14,10 @@
     Note if this parameter is turned on, the <smbconfoption name="wide links"/>
     parameter will automatically be disabled.
     </para>
+    <para>
+    See the parameter <smbconfoption name="allow insecure wide links"/>
+    if you wish to change this coupling between the two parameters.
+    </para>
 </description>
 
 <value type="default">yes</value>
diff --git a/source3/include/proto.h b/source3/include/proto.h
index 8fdd77d..28b58b2 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -1636,6 +1636,7 @@ bool lp_oplocks(int );
 bool lp_level2_oplocks(int );
 bool lp_onlyuser(int );
 bool lp_manglednames(const struct share_params *p );
+bool lp_allow_insecure_widelinks(void);
 bool lp_widelinks(int );
 bool lp_symlinks(int );
 bool lp_syncalways(int );
diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index bec525e..6ad2452 100644
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -379,6 +379,7 @@ struct global {
 	bool bMapUntrustedToDomain;
 	bool bAsyncSMBEchoHandler;
 	bool bMulticastDnsRegister;
+	bool bAllowInsecureWidelinks;
 	int ismb2_max_read;
 	int ismb2_max_write;
 	int ismb2_max_trans;
@@ -4356,6 +4357,15 @@ static struct parm_struct parm_table[] = {
 		.flags		= FLAG_ADVANCED | FLAG_SHARE,
 	},
 	{
+		.label		= "allow insecure wide links",
+		.type		= P_BOOL,
+		.p_class	= P_GLOBAL,
+		.ptr		= &Globals.bAllowInsecureWidelinks,
+		.special	= NULL,
+		.enum_list	= NULL,
+		.flags		= FLAG_ADVANCED,
+	},
+	{
 		.label		= "wide links",
 		.type		= P_BOOL,
 		.p_class	= P_LOCAL,
@@ -5996,6 +6006,7 @@ FN_LOCAL_BOOL(lp_dos_filetime_resolution, bDosFiletimeResolution)
 FN_LOCAL_BOOL(lp_fake_dir_create_times, bFakeDirCreateTimes)
 FN_GLOBAL_BOOL(lp_async_smb_echo_handler, &Globals.bAsyncSMBEchoHandler)
 FN_GLOBAL_BOOL(lp_multicast_dns_register, &Globals.bMulticastDnsRegister)
+FN_GLOBAL_BOOL(lp_allow_insecure_widelinks, &Globals.bAllowInsecureWidelinks)
 FN_LOCAL_BOOL(lp_blocking_locks, bBlockingLocks)
 FN_LOCAL_BOOL(lp_inherit_perms, bInheritPerms)
 FN_LOCAL_BOOL(lp_inherit_acls, bInheritACLS)
@@ -10322,6 +10333,10 @@ static bool lp_widelinks_internal(int snum)
 
 void widelinks_warning(int snum)
 {
+	if (lp_allow_insecure_widelinks()) {
+		return;
+	}
+
 	if (lp_unix_extensions() && lp_widelinks_internal(snum)) {
 		DEBUG(0,("Share '%s' has wide links and unix extensions enabled. "
 			"These parameters are incompatible. "
@@ -10334,7 +10349,13 @@ bool lp_widelinks(int snum)
 {
 	/* wide links is always incompatible with unix extensions */
 	if (lp_unix_extensions()) {
-		return false;
+		/*
+		 * Unless we have "allow insecure widelinks"
+		 * turned on.
+		 */
+		if (!lp_allow_insecure_widelinks()) {
+			return false;
+		}
 	}
 
 	return lp_widelinks_internal(snum);
-- 
1.7.3.1