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diff --git a/docs/docbook/projdoc/NT_Security.sgml b/docs/docbook/projdoc/NT_Security.sgml deleted file mode 100644 index 9bff25337c..0000000000 --- a/docs/docbook/projdoc/NT_Security.sgml +++ /dev/null @@ -1,335 +0,0 @@ -<chapter id="unix-permissions"> -<chapterinfo> - &author.jeremy; - <pubdate>12 Apr 1999</pubdate> -</chapterinfo> - -<title>UNIX Permission Bits and Windows NT Access Control Lists</title> - -<sect1> - <title>Viewing and changing UNIX permissions using the NT - security dialogs</title> - - <para>Windows NT clients can use their native security settings - dialog box to view and modify the underlying UNIX permissions.</para> - - <para>Note that this ability is careful not to compromise - the security of the UNIX host Samba is running on, and - still obeys all the file permission rules that a Samba - administrator can set.</para> - - <note> - <para> - All access to Unix/Linux system file via Samba is controlled at - the operating system file access control level. When trying to - figure out file access problems it is vitally important to identify - the identity of the Windows user as it is presented by Samba at - the point of file access. This can best be determined from the - Samba log files. - </para> - </note> -</sect1> - -<sect1> - <title>How to view file security on a Samba share</title> - - <para>From an NT4/2000/XP client, single-click with the right - mouse button on any file or directory in a Samba mounted - drive letter or UNC path. When the menu pops-up, click - on the <emphasis>Properties</emphasis> entry at the bottom of - the menu. This brings up the file properties dialog - box. Click on the tab <emphasis>Security</emphasis> and you - will see three buttons, <emphasis>Permissions</emphasis>, - <emphasis>Auditing</emphasis>, and <emphasis>Ownership</emphasis>. - The <emphasis>Auditing</emphasis> button will cause either - an error message <errorname>A requested privilege is not held - by the client</errorname> to appear if the user is not the - NT Administrator, or a dialog which is intended to allow an - Administrator to add auditing requirements to a file if the - user is logged on as the NT Administrator. This dialog is - non-functional with a Samba share at this time, as the only - useful button, the <command>Add</command> button will not currently - allow a list of users to be seen.</para> - -</sect1> - -<sect1> - <title>Viewing file ownership</title> - - <para>Clicking on the <command>"Ownership"</command> button - brings up a dialog box telling you who owns the given file. The - owner name will be of the form :</para> - - <para><command>"SERVER\user (Long name)"</command></para> - - <para>Where <replaceable>SERVER</replaceable> is the NetBIOS name of - the Samba server, <replaceable>user</replaceable> is the user name of - the UNIX user who owns the file, and <replaceable>(Long name)</replaceable> - is the descriptive string identifying the user (normally found in the - GECOS field of the UNIX password database). Click on the <command>Close - </command> button to remove this dialog.</para> - - <para>If the parameter <parameter>nt acl support</parameter> - is set to <constant>false</constant> then the file owner will - be shown as the NT user <command>"Everyone"</command>.</para> - - <para>The <command>Take Ownership</command> button will not allow - you to change the ownership of this file to yourself (clicking on - it will display a dialog box complaining that the user you are - currently logged onto the NT client cannot be found). The reason - for this is that changing the ownership of a file is a privileged - operation in UNIX, available only to the <emphasis>root</emphasis> - user. As clicking on this button causes NT to attempt to change - the ownership of a file to the current user logged into the NT - client this will not work with Samba at this time.</para> - - <para>There is an NT chown command that will work with Samba - and allow a user with Administrator privilege connected - to a Samba server as root to change the ownership of - files on both a local NTFS filesystem or remote mounted NTFS - or Samba drive. This is available as part of the <emphasis>Seclib - </emphasis> NT security library written by Jeremy Allison of - the Samba Team, available from the main Samba ftp site.</para> - -</sect1> - -<sect1> - <title>Viewing file or directory permissions</title> - - <para>The third button is the <command>"Permissions"</command> - button. Clicking on this brings up a dialog box that shows both - the permissions and the UNIX owner of the file or directory. - The owner is displayed in the form :</para> - - <para><command>"SERVER\user (Long name)"</command></para> - - <para>Where <replaceable>SERVER</replaceable> is the NetBIOS name of - the Samba server, <replaceable>user</replaceable> is the user name of - the UNIX user who owns the file, and <replaceable>(Long name)</replaceable> - is the descriptive string identifying the user (normally found in the - GECOS field of the UNIX password database).</para> - - <para>If the parameter <parameter>nt acl support</parameter> - is set to <constant>false</constant> then the file owner will - be shown as the NT user <command>"Everyone"</command> and the - permissions will be shown as NT "Full Control".</para> - - - <para>The permissions field is displayed differently for files - and directories, so I'll describe the way file permissions - are displayed first.</para> - - <sect2> - <title>File Permissions</title> - - <para>The standard UNIX user/group/world triple and - the corresponding "read", "write", "execute" permissions - triples are mapped by Samba into a three element NT ACL - with the 'r', 'w', and 'x' bits mapped into the corresponding - NT permissions. The UNIX world permissions are mapped into - the global NT group <command>Everyone</command>, followed - by the list of permissions allowed for UNIX world. The UNIX - owner and group permissions are displayed as an NT - <command>user</command> icon and an NT <command>local - group</command> icon respectively followed by the list - of permissions allowed for the UNIX user and group.</para> - - <para>As many UNIX permission sets don't map into common - NT names such as <command>"read"</command>, <command> - "change"</command> or <command>"full control"</command> then - usually the permissions will be prefixed by the words <command> - "Special Access"</command> in the NT display list.</para> - - <para>But what happens if the file has no permissions allowed - for a particular UNIX user group or world component ? In order - to allow "no permissions" to be seen and modified then Samba - overloads the NT <command>"Take Ownership"</command> ACL attribute - (which has no meaning in UNIX) and reports a component with - no permissions as having the NT <command>"O"</command> bit set. - This was chosen of course to make it look like a zero, meaning - zero permissions. More details on the decision behind this will - be given below.</para> - </sect2> - - <sect2> - <title>Directory Permissions</title> - - <para>Directories on an NT NTFS file system have two - different sets of permissions. The first set of permissions - is the ACL set on the directory itself, this is usually displayed - in the first set of parentheses in the normal <command>"RW"</command> - NT style. This first set of permissions is created by Samba in - exactly the same way as normal file permissions are, described - above, and is displayed in the same way.</para> - - <para>The second set of directory permissions has no real meaning - in the UNIX permissions world and represents the <command> - "inherited"</command> permissions that any file created within - this directory would inherit.</para> - - <para>Samba synthesises these inherited permissions for NT by - returning as an NT ACL the UNIX permission mode that a new file - created by Samba on this share would receive.</para> - </sect2> -</sect1> - -<sect1> - <title>Modifying file or directory permissions</title> - - <para>Modifying file and directory permissions is as simple - as changing the displayed permissions in the dialog box, and - clicking the <command>OK</command> button. However, there are - limitations that a user needs to be aware of, and also interactions - with the standard Samba permission masks and mapping of DOS - attributes that need to also be taken into account.</para> - - <para>If the parameter <parameter>nt acl support</parameter> - is set to <constant>false</constant> then any attempt to set - security permissions will fail with an <command>"Access Denied" - </command> message.</para> - - <para>The first thing to note is that the <command>"Add"</command> - button will not return a list of users in Samba (it will give - an error message of <command>"The remote procedure call failed - and did not execute"</command>). This means that you can only - manipulate the current user/group/world permissions listed in - the dialog box. This actually works quite well as these are the - only permissions that UNIX actually has.</para> - - <para>If a permission triple (either user, group, or world) - is removed from the list of permissions in the NT dialog box, - then when the <command>"OK"</command> button is pressed it will - be applied as "no permissions" on the UNIX side. If you then - view the permissions again the "no permissions" entry will appear - as the NT <command>"O"</command> flag, as described above. This - allows you to add permissions back to a file or directory once - you have removed them from a triple component.</para> - - <para>As UNIX supports only the "r", "w" and "x" bits of - an NT ACL then if other NT security attributes such as "Delete - access" are selected then they will be ignored when applied on - the Samba server.</para> - - <para>When setting permissions on a directory the second - set of permissions (in the second set of parentheses) is - by default applied to all files within that directory. If this - is not what you want you must uncheck the <command>"Replace - permissions on existing files"</command> checkbox in the NT - dialog before clicking <command>"OK"</command>.</para> - - <para>If you wish to remove all permissions from a - user/group/world component then you may either highlight the - component and click the <command>"Remove"</command> button, - or set the component to only have the special <command>"Take - Ownership"</command> permission (displayed as <command>"O" - </command>) highlighted.</para> -</sect1> - -<sect1> - <title>Interaction with the standard Samba create mask - parameters</title> - - <para>There are four parameters - to control interaction with the standard Samba create mask parameters. - These are :</para> - - <para><parameter>security mask</parameter></para> - <para><parameter>force security mode</parameter></para> - <para><parameter>directory security mask</parameter></para> - <para><parameter>force directory security mode</parameter></para> - - <para>Once a user clicks <command>"OK"</command> to apply the - permissions Samba maps the given permissions into a user/group/world - r/w/x triple set, and then will check the changed permissions for a - file against the bits set in the <ulink url="smb.conf.5.html#SECURITYMASK"> - <parameter>security mask</parameter></ulink> parameter. Any bits that - were changed that are not set to '1' in this parameter are left alone - in the file permissions.</para> - - <para>Essentially, zero bits in the <parameter>security mask</parameter> - mask may be treated as a set of bits the user is <emphasis>not</emphasis> - allowed to change, and one bits are those the user is allowed to change. - </para> - - <para>If not set explicitly this parameter is set to the same value as - the <ulink url="smb.conf.5.html#CREATEMASK"><parameter>create mask - </parameter></ulink> parameter. To allow a user to modify all the - user/group/world permissions on a file, set this parameter - to 0777.</para> - - <para>Next Samba checks the changed permissions for a file against - the bits set in the <ulink url="smb.conf.5.html#FORCESECURITYMODE"> - <parameter>force security mode</parameter></ulink> parameter. Any bits - that were changed that correspond to bits set to '1' in this parameter - are forced to be set.</para> - - <para>Essentially, bits set in the <parameter>force security mode - </parameter> parameter may be treated as a set of bits that, when - modifying security on a file, the user has always set to be 'on'.</para> - - <para>If not set explicitly this parameter is set to the same value - as the <ulink url="smb.conf.5.html#FORCECREATEMODE"><parameter>force - create mode</parameter></ulink> parameter. - To allow a user to modify all the user/group/world permissions on a file - with no restrictions set this parameter to 000.</para> - - <para>The <parameter>security mask</parameter> and <parameter>force - security mode</parameter> parameters are applied to the change - request in that order.</para> - - <para>For a directory Samba will perform the same operations as - described above for a file except using the parameter <parameter> - directory security mask</parameter> instead of <parameter>security - mask</parameter>, and <parameter>force directory security mode - </parameter> parameter instead of <parameter>force security mode - </parameter>.</para> - - <para>The <parameter>directory security mask</parameter> parameter - by default is set to the same value as the <parameter>directory mask - </parameter> parameter and the <parameter>force directory security - mode</parameter> parameter by default is set to the same value as - the <parameter>force directory mode</parameter> parameter. </para> - - <para>In this way Samba enforces the permission restrictions that - an administrator can set on a Samba share, whilst still allowing users - to modify the permission bits within that restriction.</para> - - <para>If you want to set up a share that allows users full control - in modifying the permission bits on their files and directories and - doesn't force any particular bits to be set 'on', then set the following - parameters in the &smb.conf; file in that share specific section :</para> - - <para><parameter>security mask = 0777</parameter></para> - <para><parameter>force security mode = 0</parameter></para> - <para><parameter>directory security mask = 0777</parameter></para> - <para><parameter>force directory security mode = 0</parameter></para> -</sect1> - -<sect1> - <title>Interaction with the standard Samba file attribute - mapping</title> - - <para>Samba maps some of the DOS attribute bits (such as "read - only") into the UNIX permissions of a file. This means there can - be a conflict between the permission bits set via the security - dialog and the permission bits set by the file attribute mapping. - </para> - - <para>One way this can show up is if a file has no UNIX read access - for the owner it will show up as "read only" in the standard - file attributes tabbed dialog. Unfortunately this dialog is - the same one that contains the security info in another tab.</para> - - <para>What this can mean is that if the owner changes the permissions - to allow themselves read access using the security dialog, clicks - <command>"OK"</command> to get back to the standard attributes tab - dialog, and then clicks <command>"OK"</command> on that dialog, then - NT will set the file permissions back to read-only (as that is what - the attributes still say in the dialog). This means that after setting - permissions and clicking <command>"OK"</command> to get back to the - attributes dialog you should always hit <command>"Cancel"</command> - rather than <command>"OK"</command> to ensure that your changes - are not overridden.</para> -</sect1> - -</chapter> |