[SCM] Samba Shared Repository - branch master updated

Volker Lendecke vlendec at samba.org
Fri Oct 28 07:25:02 UTC 2022


The branch, master has been updated
       via  69273c3a836 docs-xml: ea support option restricted to user ns
       via  34c6db64c2f s3: smbd: Consistently map EAs to user namespace
      from  8c94bbba270 testprogs/blackbox: add 'net ads keytab delete' tests to test_net_ads.sh

https://git.samba.org/?p=samba.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit 69273c3a836ede97c7fde74e2f1fdc84e92ec86f
Author: Daniel Kobras <kobras at puzzle-itc.de>
Date:   Fri Oct 21 16:40:14 2022 +0200

    docs-xml: ea support option restricted to user ns
    
    Update documentation to match current behavior.
    
    Signed-off-by: Daniel Kobras <kobras at puzzle-itc.de>
    Reviewed-by: Jeremy Allison <jra at samba.org>
    Reviewed-by: Volker Lendecke <vl at samba.org>
    
    Autobuild-User(master): Volker Lendecke <vl at samba.org>
    Autobuild-Date(master): Fri Oct 28 07:24:18 UTC 2022 on sn-devel-184

commit 34c6db64c2ff62673f8df218487cda4139c10843
Author: Daniel Kobras <kobras at puzzle-itc.de>
Date:   Mon Sep 26 10:27:19 2022 +0200

    s3: smbd: Consistently map EAs to user namespace
    
    Samba has always been mapping Windows EAs to the 'user' namespace on the
    POSIX side. However, in the opposite direction, the mapping would also map
    other user-readable POSIX EA namespaces to Windows EAs, only stripping the
    'user' namespace prefix, and passing all other EA names verbatim.
    
    This means any POSIX EA 'other.foo' collides with 'user.other.foo' on the
    Windows side, hence the mapping of non-user namespaces is unreliable.
    Also, copy operations via Windows would rename an existing POSIX EA
    'other.foo' in the source file to 'user.other.foo' in the destination. The
    'user' namespace, however, may not be enabled on the underlying filesystem,
    leading to subtle failure modes like the ones reported in eg.
    <https://bugzilla.samba.org/show_bug.cgi?id=15186>
    
    Fix the issues by restricting the mapping to the 'user' POSIX EA namespace
    consistently for either direction.
    
    Link: https://lists.samba.org/archive/samba-technical/2022-September/137634.html
    BUG: https://bugzilla.samba.org/show_bug.cgi?id=15186
    
    Signed-off-by: Daniel Kobras <kobras at puzzle-itc.de>
    Reviewed-by: Michael Weiser <michael.weiser at atos.net>
    Tested-by: Michael Weiser <michael.weiser at atos.net>
    Reviewed-by: Jeremy Allison <jra at samba.org>
    Reviewed-by: Volker Lendecke <vl at samba.org>

-----------------------------------------------------------------------

Summary of changes:
 docs-xml/smbdotconf/protocol/easupport.xml |  9 +++++++++
 source3/smbd/smb2_trans2.c                 | 23 +++++++++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)


Changeset truncated at 500 lines:

diff --git a/docs-xml/smbdotconf/protocol/easupport.xml b/docs-xml/smbdotconf/protocol/easupport.xml
index fd425e8b514..f111a4c23be 100644
--- a/docs-xml/smbdotconf/protocol/easupport.xml
+++ b/docs-xml/smbdotconf/protocol/easupport.xml
@@ -14,8 +14,17 @@
 	attributes (e.g. the getfattr<manvolnum>1</manvolnum> / setfattr<manvolnum>1</manvolnum>
 	utilities must work).
 	</para></listitem>
+	<listitem><para>Access to extended user attributes must be allowed by the underlying
+        filesystem (e.g. when mounted with a system-dependent option like user_xattr on Linux).
+	</para></listitem>
     </itemizedlist>
     <para>
+    This option exposes the "user" attribute namespace from the underlying filesystem to
+    clients. In order to match Windows conventions, the namespace prefix ("user.") is
+    stripped from the attribute name on the client side. The handling of further attribute
+    namespaces (like "security", "system", or "trusted") is not affected by this option.
+    </para>
+    <para>
     Note that the SMB protocol allows setting attributes whose value is 64K bytes long,
     and that on NTFS, the maximum storage space for extended attributes per file is 64K.
     On some filesystem the limits may be lower. Filesystems with too limited EA
diff --git a/source3/smbd/smb2_trans2.c b/source3/smbd/smb2_trans2.c
index 95cecce96e1..69f6184bff1 100644
--- a/source3/smbd/smb2_trans2.c
+++ b/source3/smbd/smb2_trans2.c
@@ -454,7 +454,19 @@ static NTSTATUS get_ea_list_from_fsp(TALLOC_CTX *mem_ctx,
 		struct ea_list *listp;
 		fstring dos_ea_name;
 
-		if (strnequal(names[i], "system.", 7)
+		/*
+		 * POSIX EA names are divided into several namespaces by
+		 * means of string prefixes. Usually, the system controls
+		 * semantics for each namespace, but the 'user' namespace is
+		 * available for arbitrary use, which comes closest to
+		 * Windows EA semantics. Hence, we map POSIX EAs from the
+		 * 'user' namespace to Windows EAs, and just ignore all the
+		 * other namespaces. Also, a few specific names in the 'user'
+		 * namespace are used by Samba internally. Filter them out as
+		 * well, and only present the EAs that are available for
+		 * arbitrary use.
+		 */
+		if (!strnequal(names[i], "user.", 5)
 		    || samba_private_attr_name(names[i]))
 			continue;
 
@@ -780,7 +792,14 @@ NTSTATUS set_ea(connection_struct *conn, files_struct *fsp,
 		int ret;
 		fstring unix_ea_name;
 
-		fstrcpy(unix_ea_name, "user."); /* All EA's must start with user. */
+		/*
+		 * Complementing the forward mapping from POSIX EAs to
+		 * Windows EAs in get_ea_list_from_fsp(), here we map in the
+		 * opposite direction from Windows EAs to the 'user' namespace
+		 * of POSIX EAs. Hence, all POSIX EA names the we set here must
+		 * start with a 'user.' prefix.
+		 */
+		fstrcpy(unix_ea_name, "user.");
 		fstrcat(unix_ea_name, ea_list->ea.name);
 
 		canonicalize_ea_name(fsp, unix_ea_name);


-- 
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