<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
<!ENTITY % globalentities SYSTEM '../entities/global.entities'> %globalentities;
-<!ENTITY NetBIOS SYSTEM "NetBIOS.xml">
-<!ENTITY Architecture SYSTEM "architecture.xml">
-<!ENTITY debug SYSTEM "debug.xml">
-<!ENTITY internals SYSTEM "internals.xml">
-<!ENTITY parsing SYSTEM "parsing.xml">
-<!ENTITY unix-smb SYSTEM "unix-smb.xml">
-<!ENTITY CodingSuggestions SYSTEM "CodingSuggestions.xml">
-<!ENTITY Tracing SYSTEM "Tracing.xml">
-<!ENTITY cifsntdomain SYSTEM "cifsntdomain.xml">
-<!ENTITY printing SYSTEM "printing.xml">
-<!ENTITY wins SYSTEM "wins.xml">
-<!ENTITY sam SYSTEM "sam.xml">
-<!ENTITY encryption SYSTEM "encryption.xml">
-<!ENTITY rpc-plugin SYSTEM "rpc_plugin.xml">
-<!ENTITY modules SYSTEM "modules.xml">
-<!ENTITY packagers SYSTEM "packagers.xml">
-<!ENTITY contributing SYSTEM "contributing.xml">
-<!ENTITY vfs SYSTEM "vfs.xml">
-<!ENTITY windows-deb SYSTEM "windows-debug.xml">
-<!ENTITY registry SYSTEM "registry.xml">
]>
-<book id="Samba-Developers-Guide">
+<book id="Samba-Developers-Guide"
+ xmlns:xi="http://www.w3.org/2003/XInclude">
<title>SAMBA Developers Guide</title>
<preface>
<title>Attributions</title>
- &attributions-dev;
+ <xi:include href="attributions.xml"/>
</preface>
<part>
<title>The protocol</title>
- &NetBIOS;
- &unix-smb;
- &cifsntdomain;
+ <xi:include href="NetBIOS.xml"/>
+ <xi:include href="unix-smb.xml"/>
+ <xi:include href="cifsntdomain.xml"/>
</part>
<part>
<title>Samba Basics</title>
-&Architecture;
-&debug;
-&internals;
-&CodingSuggestions;
-&contributing;
-&modules;
+ <xi:include href="architecture.xml"/>
+ <xi:include href="debug.xml"/>
+ <xi:include href="internals.xml"/>
+ <xi:include href="CodingSuggestions.xml"/>
+ <xi:include href="contributing.xml"/>
+ <xi:include href="modules.xml"/>
</part>
<part>
<title>Samba Subsystems</title>
- &sam;
- &rpc-plugin;
- &vfs;
- ®istry;
- &parsing;
- &wins;
- &encryption;
+ <xi:include href="rpc_plugin.xml"/>
+ <xi:include href="vfs.xml"/>
+ <xi:include href="registry.xml"/>
+ <xi:include href="parsing.xml"/>
+ <xi:include href="wins.xml"/>
+ <xi:include href="encryption.xml"/>
</part>
<part>
<title>Debugging and tracing</title>
-&Tracing;
-&windows-deb;
-&printing;
+ <xi:include href="Tracing.xml"/>
+ <xi:include href="windows-debug.xml"/>
+ <xi:include href="printing.xml"/>
</part>
<part><title>Appendices</title>
- &packagers;
+ <xi:include href="packagers.xml"/>
</part>
</book>
+++ /dev/null
-<chapter id="sam">
-
-<chapterinfo>
- <author>
- <firstname>Andrew</firstname><surname>Bartlett</surname>
- </author>
- <pubdate>1 October 2002</pubdate>
-</chapterinfo>
-
-<title>The Upcoming SAM System</title>
-
-<sect1>
-<title>Security in the 'new SAM'</title>
-
-<para>One of the biggest problems with passdb is it's implementation of
-'security'. Access control is on a 'are you root at the moment' basis,
-and it has no concept of NT ACLs. Things like ldapsam had to add
-'magic' 'are you root' checks.</para>
-
-<para>We took this very seriously when we started work, and the new structure
-is designed with this in mind, from the ground up. Each call to the SAM
-has a NT_TOKEN and (if relevant) an 'access desired'. This is either
-provided as a parameter, or implicitly supplied by the object being
-accessed.</para>
-
-<para>
-For example, when you call
-</para>
-
-<programlisting>
-NTSTATUS sam_get_account_by_name(const SAM_CONTEXT *context, const
-NT_USER_TOKEN *access_token, uint32 access_desired, const char *domain,
-const char *name, SAM_ACCOUNT_HANDLE **account)
-</programlisting>
-
-<para>
-The context can be NULL (and is used to allow import/export by setting
-up 2 contexts, and allowing calls on both simultaneously)
-</para>
-
-<para>
-The access token *must* be specified. Normally the user's token out of
-current_user, this can also be a global 'system' context.
-</para>
-
-<para>
-The access desired is as per the ACL, for passing to the seaccess stuff.
-</para>
-
-<para>
-The domain/username are standard. Even if we only have one domain,
-keeping this ensures that we don't get 'unqualified' usernames (same
-problem as we had with unqualified SIDs).
-</para>
-
-<para>
-We return a 'handle'. This is opaque to the rest of Samba, but is
-operated on by get/set routines, all of which return NTSTATUS.
-</para>
-
-<para>
-The access checking is done by the SAM module. The reason it is not
-done 'above' the interface is to ensure a 'choke point'. I put a lot of
-effort into the auth subsystem to ensure we never 'accidentally' forgot
-to check for null passwords, missed a restriction etc. I intend the SAM
-to be written with the same caution.
-</para>
-
-<para>
-The reason the access checking is not handled by the interface itself is
-due to the different implementations it make take on. For example, on
-ADS, you cannot set a password over a non-SSL connection. Other
-backends may have similar requirements - we need to leave this policy up
-to the modules. They will naturally have access to 'helper' procedures
-and good examples to avoid mishaps.
-</para>
-
-<para>
-(Furthermore, some backends my actually chose to push the whole ACL
-issue to the remote server, and - assuming ldap for this example - bind
-as the user directly)
-</para>
-
-<para>
-Each returned handle has an internal 'access permitted', which allows
-the 'get' and 'set' routines to return 'ACCESS_DENIED' for things that
-were not able to be retrieved from the backend. This removes the need
-to specify the NT_TOKEN on every operation, and allows for 'object not
-present' to be easily distinguished from 'access denied'.
-</para>
-
-<para>
-When you 'set' an object (calling sam_update_account) the internal
-details are again used. Each change that has been made to the object
-has been flagged, so as to avoid race conditions (on unmodified
-components) and to avoid violating any extra ACL requirements on the
-actual data store (like the LDAP server).
-</para>
-
-<para>
-Finally, we have generic get_sec_desc() and set_sec_desc() routines to
-allow external ACL manipulation. These do lookups based on SID.
-</para>
-
-</sect1>
-
-<sect1>
-<title>Standalone from UNIX</title>
-
-<para>
-One of the primary tenants of the 'new SAM' is that it would not attempt
-to deal with 'what unix id for that'. This would be left to the 'SMS'
-(Sid Mapping System') or SID farm, and probably administered via
-winbind. We have had constructive discussion on how 'basic' unix
-accounts like 'root' would be handled, and we think this can work.
-Accounts not preexisting in unix would be served up via winbind.
-</para>
-
-<para>
-This is an *optional* part, and my preferred end-game. We have a fare
-way to go before things like winbind up to it however.
-</para>
-
-</sect1>
-
-<sect1>
-<title>Handles and Races in the new SAM</title>
-
-<para>
-One of the things that the 'new SAM' work has tried to face is both
-compatibility with existing code, and a closer alignment to the SAMR
-interface. I consider SAMR to be a 'primary customer' to the this work,
-because if we get alignment with that wrong, things get more, rather
-than less complex. Also, most other parts of Samba are much more
-flexible with what they can allow.
-</para>
-
-<para>
-In any case, that was a decision taken as to how the general design
-would progress. BTW, my understanding of SAMR may be completely flawed.
-</para>
-
-<para>
-One of the most race-prone areas of the new code is the conflicting
-update problem. We have taken two approaches:
-</para>
-
-<itemizedlist>
-<listitem>
-<para>'Not conflicting' conflicts. Due to the way usrmgr operates, it will
-open a user, display all the properties and *save* them all, even if you
-don't change any.
-</para>
-
-<para>
-For this, see what I've done in rpc_server/srv_samr_util.c. I intend
-to take this one step further, and operate on the 'handle' that the
-values were read from. This should mean that we only update things that
-have *really* changed.
-</para>
-</listitem>
-
-<listitem>
-<para>
-'conflicting' updates: Currently we don't deal with this (in passdb
-or the new sam stuff), but the design is sufficiently flexible to 'deny'
-a second update. I don't foresee locking records however.
-</para>
-</listitem>
-</itemizedlist>
-
-</sect1>
-
-<sect1>
-<title>Layers</title>
-
-<sect2>
-<title>Application</title>
-
-<para>
-This is where smbd, samtest and whatever end-user replacement we have
-for pdbedit sits. They use only the SAM interface, and do not get
-'special knowledge' of what is below them.
-</para>
-</sect2>
-<sect2>
-<title>SAM Interface</title>
-
-<para>
-This level 'owns' the various handle structures, the get/set routines on
-those structures and provides the public interface. The application
-layer may initialize a 'context' to be passed to all interface routines,
-else a default, self-initialising context will be supplied. This layser
-finds the appropriate backend module for the task, and tries very hard
-not to need to much 'knowledge'. It should just provide the required
-abstraction to the modules below, and arrange for their initial loading.
-</para>
-
-<para>
-We could possibly add ACL checking at this layer, to avoid discrepancies
-in implementation modules.
-</para>
-
-</sect2>
-
-<sect2>
-<title>SAM Modules</title>
-
-<para>
-These do not communicate with the application directly, only by setting
-values in the handles, and receiving requests from the interface. These
-modules are responsible for translating values from the handle's
-.private into (say) an LDAP modification list. The module is expected
-to 'know' things like it's own domain SID, domain name, and any other
-state attached to the SAM. Simpler modules may call back to some helper
-routine.
-</para>
-
-</sect2>
-</sect1>
-
-<sect1>
-<title>SAM Modules</title>
-
-<sect2>
-<title>Special Module: sam_passdb</title>
-
-<para>
-In order for there to be a smooth transition, kai is writing a module
-that reads existing passdb backends, and translates them into SAM
-replies. (Also pulling data from the account policy DB etc). We also
-intend to write a module that does the reverse - gives the SAM a passdb
-interface.
-</para>
-</sect2>
-
-<sect2>
-<title>sam_ads</title>
-<para>
-This is the first of the SAM modules to be committed to the tree -
-mainly because I needed to coordinate work with metze (who authored most
-of it). This module aims to use Samba's libads code to provide an
-Active Directory LDAP client, suitable for use on a mixed-mode DC.
-While it is currently being tested against Win2k servers (with a
-password in the smb.conf file) it is expected to eventually use a
-(possibly modified) OpenLDAP server. We hope that this will assist in
-the construction of an Samba AD DC.
-</para>
-
-<para>
-We also intend to construct a Samba 2.2/3.0 compatible ldap module,
-again using libads code.
-</para>
-</sect2>
-</sect1>
-
-<sect1>
-<title>Memory Management</title>
-
-<para>
-The 'new SAM' development effort also concerned itself with getting a
-sane implementation of memory management. It was decided that we would
-be (as much as possible) talloc based, using an 'internal talloc
-context' on many objects. That is, the creation of an object would
-initiate it's own internal talloc context, and this would be used for
-all operations on that object. Much of this is already implemented in
-passdb. Also, like passdb, it will be possible to specify that some
-object actually be created on a specified context.
-</para>
-
-<para>
-Memory management is important here because the APIs in the 'new SAM' do
-not use 'pdb_init()' or an equivalent. They always allocate new
-objects. Enumeration's are slightly different, and occur on a supplied
-context that 'owns' the entire list, rather than per-element. (the
-enumeration functions return an array of all elements - not full handles
-just basic (and public) info) Likewise for things that fill in a char
-**.
-</para>
-
-<para>For example:</para>
-
-<para><programlisting>
-NTSTATUS sam_lookup_sid(const SAM_CONTEXT *context, const NT_USER_TOKEN
-*access_token, TALLOC_CTX *mem_ctx, const DOM_SID *sid, char **name,
-uint32 *type)
-</programlisting></para>
-
-<para>Takes a context to allocate the 'name' on, while:</para>
-
-<para><programlisting>
-NTSTATUS sam_get_account_by_sid(const SAM_CONTEXT *context, const
-NT_USER_TOKEN *access_token, uint32 access_desired, const DOM_SID
-*accountsid, SAM_ACCOUNT_HANDLE **account)
-</programlisting></para>
-
-<para>Allocates a handle and stores the allocation context on that handle.</para>
-
-<para>I think that the following:</para>
-
-<para><programlisting>
-NTSTATUS sam_enum_accounts(const SAM_CONTEXT *context, const
-NT_USER_TOKEN *access_token, const DOM_SID *domainsid, uint16 acct_ctrl,
-int32 *account_count, SAM_ACCOUNT_ENUM **accounts)
-</programlisting></para>
-
-</sect1>
-
-<sect1>
-<title>Testing</title>
-
-<para>
-Testing is vital in any piece of software, and Samba is certainly no
-exception. In designing this new subsystem, we have taken care to ensure
-it is easily tested, independent of outside protocols.
-</para>
-
-<para>
-To this end, Jelmer has constructed 'samtest'.
-</para>
-
-<para>
-This utility (see torture/samtest.c) is structured like rpcclient, but
-instead operates on the SAM subsystem. It creates a 'custom' SAM
-context, that may be distinct from the default values used by the rest
-of the system, and can load a separate configuration file.
-</para>
-
-<para>
-A small number of commands are currently implemented, but these have
-already proved vital in testing. I expect SAM module authors will find
-it particularly valuable.
-</para>
-
-<para>Example useage:</para>
-
-<para><prompt>$</prompt> <command>bin/samtest</command></para>
-
-<para><programlisting>
-> context ads:ldap://192.168.1.96
-</programlisting>
-(this loads a new context, using the new ADS module. The parameter is
-the 'location' of the ldap server)
-</para>
-
-<para><programlisting>
-> lookup_name DOMAIN abartlet
-</programlisting>
-(returns a sid).
-</para>
-
-<para>
-Because the 'new SAM' is NT ACL based, there will be a command to
-specify an arbitrary NT ACL, but for now it uses 'system' by default.
-</para>
-</sect1>
-</chapter>
git.samba.org / import / samba-docs-svnimport.git / commitdiff