UID/GID override on CIFS mounts to Samba and proposed new mount parameter to disable Unix Extensions on the client

UID/GID override on CIFS mounts to Samba and proposed new mount parameter to disable Unix Extensions on the client

[Steve French]

[-- Attachment #1: Type: text/plain, Size: 1417 bytes --]

When CIFS Unix Extensions are negotiated we get the Unix uid and gid
owners of the file from the server (on the Unix Query Path Info
levels), but if the server's uids don't match the client uid's users
were having to disable the Unix Extensions (which turned off features
they still wanted).   The attached patch allows users to override uid
and/or gid for file/directory owner with a default uid and/or gid
specified at mount (as is often done when mounting from Linux cifs
client to Windows server).  The attached patch also displays the uid
and gid used by default in /proc/mounts (if applicable).

I also would like suggestions on what we should call a proposed mount
option (not coded yet) which would disable the CIFS Unix Extensions on
a per-mount basis (or more likely actually would require it on the
first mount to the server, subsequent mounts would probably inherit
the capabilities).  Current cifs code can disable mount options before
a mount by specifying

     "echo 0 > /proc/fs/cifs/LinuxExtensionsEnabled")

but it might be easier to specify it on mount (e.g.
"nolinuxextensions" or "linuxextensions=no" ?).    Slightly harder
would be disabling Unix Extensions after the user has already mounted
(with Unix Extensions) to the same server (perhaps to a different
share).  How important would it be to have two mounts to the same
server one with unix extensions and one without?

-- 
Thanks,

Steve

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: allow-override-of-default-uid-on-unix-cifs-mounts.patch --]
[-- Type: text/x-patch; name="allow-override-of-default-uid-on-unix-cifs-mounts.patch", Size: 9343 bytes --]

diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES
index 301631c..62dcf63 100644
--- a/fs/cifs/CHANGES
+++ b/fs/cifs/CHANGES
@@ -2,7 +2,11 @@ Version 1.49
 ------------
 IPv6 support.  Enable ipv6 addresses to be passed on mount (put the ipv6
 address after the "ip=" mount option, at least until mount.cifs is fixed to
-handle DNS host to ipv6 name translation).
+handle DNS host to ipv6 name translation).  Accept override of uid or gid
+on mount even when Unix Extensions are negotiated (it used to be ignored
+when Unix Extensions were ignored).  This allows users to override the
+default uid and gid for files when they are certain that the uids or
+gids on the server do not match those of the client.
 
 Version 1.48
 ------------
diff --git a/fs/cifs/README b/fs/cifs/README
index 080c5eb..93fe359 100644
--- a/fs/cifs/README
+++ b/fs/cifs/README
@@ -257,13 +257,19 @@ A partial list of the supported mount op
 		mount.	
   domain	Set the SMB/CIFS workgroup name prepended to the
 		username during CIFS session establishment
-  uid		If CIFS Unix extensions are not supported by the server
-		this overrides the default uid for inodes. For mounts to
-		servers which do support the CIFS Unix extensions, such
-		as a properly configured Samba server, the server provides
-		the uid, gid and mode.  For servers which do not support
-		the Unix extensions, the default uid (and gid) returned on
-		lookup of existing files is the uid (gid) of the person
+  uid		Set the default uid for inodes. For mounts to servers
+		which do support the CIFS Unix extensions, such as a
+		properly configured Samba server, the server provides
+		the uid, gid and mode so this parameter should  not be
+		specified unless the server and clients uid and gid
+		numbering differ.  If the server and client are in the
+		same domain (e.g. running winbind or nss_ldap) and
+		the server supports the Unix Extensions then the uid
+		and gid can be retrieved from the server (and uid
+		and gid would not have to be specifed on the mount. 
+		For servers which do not support the CIFS Unix
+		extensions, the default uid (and gid) returned on lookup
+		of existing files will be the uid (gid) of the person
 		who executed the mount (root, except when mount.cifs
 		is configured setuid for user mounts) unless the "uid=" 
 		(gid) mount option is specified.  For the uid (gid) of newly
@@ -281,8 +287,7 @@ A partial list of the supported mount op
 		the client.  Note that the mount.cifs helper must be
 		at version 1.10 or higher to support specifying the uid
 		(or gid) in non-numberic form.
-  gid		If CIFS Unix extensions are not supported by the server
-		this overrides the default gid for inodes.
+  gid		Set the default gid for inodes (similar to above).
   file_mode     If CIFS Unix extensions are not supported by the server
 		this overrides the default mode for file inodes.
   dir_mode      If CIFS Unix extensions are not supported by the server 
diff --git a/fs/cifs/TODO b/fs/cifs/TODO
index b70a69b..78b620e 100644
--- a/fs/cifs/TODO
+++ b/fs/cifs/TODO
@@ -80,7 +80,7 @@ need to add ability to set time to serve
 
 u) DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too)
 
-v) mount check for unmatched uids - and uid override
+v) mount check for unmatched uids
 
 w) Add mount option for Linux extension disable per mount, and partial
 disable per mount (uid off, symlink/fifo/mknod on but what about posix acls?)
diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index fd1e52e..4cc2012 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -22,12 +22,14 @@
 #define CIFS_MOUNT_SET_UID      2 /* set current->euid in create etc. */
 #define CIFS_MOUNT_SERVER_INUM  4 /* inode numbers from uniqueid from server */
 #define CIFS_MOUNT_DIRECT_IO    8 /* do not write nor read through page cache */
-#define CIFS_MOUNT_NO_XATTR  0x10 /* if set - disable xattr support */
-#define CIFS_MOUNT_MAP_SPECIAL_CHR 0x20 /* remap illegal chars in filenames */
-#define CIFS_MOUNT_POSIX_PATHS	0x40 /* Negotiate posix pathnames if possible. */
-#define CIFS_MOUNT_UNX_EMUL	0x80 /* Network compat with SFUnix emulation */
-#define CIFS_MOUNT_NO_BRL	0x100 /* No sending byte range locks to srv */
-#define CIFS_MOUNT_CIFS_ACL	0x200 /* send ACL requests to non-POSIX srv */
+#define CIFS_MOUNT_NO_XATTR     0x10  /* if set - disable xattr support       */
+#define CIFS_MOUNT_MAP_SPECIAL_CHR 0x20 /* remap illegal chars in filenames   */
+#define CIFS_MOUNT_POSIX_PATHS  0x40  /* Negotiate posix pathnames if possible*/
+#define CIFS_MOUNT_UNX_EMUL     0x80  /* Network compat with SFUnix emulation */
+#define CIFS_MOUNT_NO_BRL       0x100 /* No sending byte range locks to srv   */
+#define CIFS_MOUNT_CIFS_ACL     0x200 /* send ACL requests to non-POSIX srv   */
+#define CIFS_MOUNT_OVERR_UID    0x400 /* override uid returned from server    */
+#define CIFS_MOUNT_OVERR_GID    0x800 /* override gid returned from server    */
 
 struct cifs_sb_info {
 	struct cifsTconInfo *tcon;	/* primary mount */
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index dd03e68..24eb0c5 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -306,6 +306,14 @@ cifs_show_options(struct seq_file *s, st
 					   cifs_sb->tcon->ses->domainName);
 			}
 		}
+		if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
+			seq_printf(s, ",posixpaths");
+		if((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID) ||
+		   !(cifs_sb->tcon->ses->capabilities & CAP_UNIX))
+			seq_printf(s, ",uid=%d", cifs_sb->mnt_uid);
+		if((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID) ||
+		   !(cifs_sb->tcon->ses->capabilities & CAP_UNIX))
+			seq_printf(s, ",gid=%d", cifs_sb->mnt_gid);
 		seq_printf(s, ",rsize=%d",cifs_sb->rsize);
 		seq_printf(s, ",wsize=%d",cifs_sb->wsize);
 	}
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index c1af159..a7c6c35 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -75,6 +75,8 @@ struct smb_vol {
 	unsigned retry:1;
 	unsigned intr:1;
 	unsigned setuids:1;
+	unsigned override_uid:1;
+	unsigned override_gid:1;
 	unsigned noperm:1;
 	unsigned no_psx_acl:1; /* set if posix acl support should be disabled */
 	unsigned cifs_acl:1;
@@ -1042,11 +1044,13 @@ cifs_parse_mount_options(char *options,
 			if (value && *value) {
 				vol->linux_uid =
 					simple_strtoul(value, &value, 0);
+				vol->override_uid = 1;
 			}
 		} else if (strnicmp(data, "gid", 3) == 0) {
 			if (value && *value) {
 				vol->linux_gid =
 					simple_strtoul(value, &value, 0);
+				vol->override_gid = 1;
 			}
 		} else if (strnicmp(data, "file_mode", 4) == 0) {
 			if (value && *value) {
@@ -1989,7 +1993,10 @@ cifs_mount(struct super_block *sb, struc
 			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL;
 		if(volume_info.cifs_acl)
 			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
-
+		if(volume_info.override_uid)
+			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
+		if(volume_info.override_gid)
+			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_GID;
 		if(volume_info.direct_io) {
 			cFYI(1,("mounting share using direct i/o"));
 			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index f74f37c..fe5d326 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -139,8 +139,17 @@ int cifs_get_inode_info_unix(struct inod
 			inode->i_mode |= S_IFREG;
 			cFYI(1,("unknown type %d",type));
 		}
-		inode->i_uid = le64_to_cpu(findData.Uid);
-		inode->i_gid = le64_to_cpu(findData.Gid);
+		
+		if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID)
+			inode->i_uid = cifs_sb->mnt_uid;
+		else
+			inode->i_uid = le64_to_cpu(findData.Uid);
+
+		if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID)
+			inode->i_gid = cifs_sb->mnt_gid;
+		else
+			inode->i_gid = le64_to_cpu(findData.Gid);
+			
 		inode->i_nlink = le64_to_cpu(findData.Nlinks);
 
 		spin_lock(&inode->i_lock);
@@ -523,6 +532,8 @@ int cifs_get_inode_info(struct inode **p
 		   or retrieve from NTFS stream extended attribute */
 		if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 			/* fill in uid, gid, mode from server ACL */
+			/* BB FIXME this should also take into account the
+			 * default uid specified on mount if present */
 			get_sfu_uid_mode(inode, search_path, cifs_sb, xid);
 		} else if (atomic_read(&cifsInfo->inUse) == 0) {
 			inode->i_uid = cifs_sb->mnt_uid;
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index b80b0fc..24d3133 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -357,8 +357,14 @@ static void unix_fill_in_inode(struct in
 		cFYI(1,("unknown inode type %d",type)); 
 	}
 
-	tmp_inode->i_uid = le64_to_cpu(pfindData->Uid);
-	tmp_inode->i_gid = le64_to_cpu(pfindData->Gid);
+	if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID)
+		tmp_inode->i_uid = cifs_sb->mnt_uid;
+	else
+		tmp_inode->i_uid = le64_to_cpu(pfindData->Uid);
+	if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID)
+		tmp_inode->i_gid = cifs_sb->mnt_gid;
+	else
+		tmp_inode->i_gid = le64_to_cpu(pfindData->Gid);
 	tmp_inode->i_nlink = le64_to_cpu(pfindData->Nlinks);
 
 	spin_lock(&tmp_inode->i_lock);
@@ -382,7 +388,6 @@ static void unix_fill_in_inode(struct in
 				tmp_inode->i_fop = &cifs_file_direct_nobrl_ops;
 			else
 				tmp_inode->i_fop = &cifs_file_direct_ops;
-		
 		} else if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 			tmp_inode->i_fop = &cifs_file_nobrl_ops;
 		else

Re: UID/GID override on CIFS mounts to Samba and proposed new mount parameter to disable Unix Extensions on the client

[Anton Altaparmakov]

On 30 Apr 2007, at 15:26, Steve French wrote:
> When CIFS Unix Extensions are negotiated we get the Unix uid and gid
> owners of the file from the server (on the Unix Query Path Info
> levels), but if the server's uids don't match the client uid's users
> were having to disable the Unix Extensions (which turned off features
> they still wanted).   The attached patch allows users to override uid
> and/or gid for file/directory owner with a default uid and/or gid
> specified at mount (as is often done when mounting from Linux cifs
> client to Windows server).  The attached patch also displays the uid
> and gid used by default in /proc/mounts (if applicable).
>
> I also would like suggestions on what we should call a proposed mount
> option (not coded yet) which would disable the CIFS Unix Extensions on
> a per-mount basis (or more likely actually would require it on the
> first mount to the server, subsequent mounts would probably inherit
> the capabilities).  Current cifs code can disable mount options before
> a mount by specifying
>
>     "echo 0 > /proc/fs/cifs/LinuxExtensionsEnabled")
>
> but it might be easier to specify it on mount (e.g.
> "nolinuxextensions" or "linuxextensions=no" ?).    Slightly harder
> would be disabling Unix Extensions after the user has already mounted
> (with Unix Extensions) to the same server (perhaps to a different
> share).  How important would it be to have two mounts to the same
> server one with unix extensions and one without?

Why "linuxextensions"?  I thought those are the "UNIX extensions"  
that Samba provides no matter on which platform it is run such as  
Linux, Mac OS X, Solaris, etc...

Best regards,

	Anton
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer, http://www.linux-ntfs.org/

Re: UID/GID override on CIFS mounts to Samba and proposed new mount parameter to disable Unix Extensions on the client

[Steve French]

The CIFS Unix Extensions are used by multiple clients now (not just
Linux) but originally I thought that it might be confusing to Linux
users  to call the configuration setting for that in /proc/fs/cifs
"Unix" instead of "Linux" (and since it has been there for years and
is externally visible, it is probably not a good idea to change its
name in proc) but for a mount option it might make sense to refer to
them as "unixextensions=no" (similar to Samba server's smb.conf
setting name).  I also though about calling it:

"noposix" or "noposixpaths" ("posix paths" are one of the capabilities
negotiated when Unix Extension are turned on) but that might imply
that the client is turning off compensations that is can use for
mounting to Windows (like JRA's byte range lock emulation, and the
optional SFU-like emulation of device files and symlinks)

On 4/30/07, Anton Altaparmakov <aia21@cam.ac.uk> wrote:
> On 30 Apr 2007, at 15:26, Steve French wrote:
> > When CIFS Unix Extensions are negotiated we get the Unix uid and gid
> > owners of the file from the server (on the Unix Query Path Info
> > levels), but if the server's uids don't match the client uid's users
> > were having to disable the Unix Extensions (which turned off features
> > they still wanted).   The attached patch allows users to override uid
> > and/or gid for file/directory owner with a default uid and/or gid
> > specified at mount (as is often done when mounting from Linux cifs
> > client to Windows server).  The attached patch also displays the uid
> > and gid used by default in /proc/mounts (if applicable).
> >
> > I also would like suggestions on what we should call a proposed mount
> > option (not coded yet) which would disable the CIFS Unix Extensions on
> > a per-mount basis (or more likely actually would require it on the
> > first mount to the server, subsequent mounts would probably inherit
> > the capabilities).  Current cifs code can disable mount options before
> > a mount by specifying
> >
> >     "echo 0 > /proc/fs/cifs/LinuxExtensionsEnabled")
> >
> > but it might be easier to specify it on mount (e.g.
> > "nolinuxextensions" or "linuxextensions=no" ?).    Slightly harder
> > would be disabling Unix Extensions after the user has already mounted
> > (with Unix Extensions) to the same server (perhaps to a different
> > share).  How important would it be to have two mounts to the same
> > server one with unix extensions and one without?
>
> Why "linuxextensions"?  I thought those are the "UNIX extensions"
> that Samba provides no matter on which platform it is run such as
> Linux, Mac OS X, Solaris, etc...
>
> Best regards,
>
>         Anton


-- 
Thanks,

Steve

Re: UID/GID override on CIFS mounts to Samba and proposed new mount parameter to disable Unix Extensions on the client

[Randy Dunlap]

On Mon, 30 Apr 2007 09:26:16 -0500 Steve French wrote:

replying to the inline patch  :(

Use a space between "if" and "("   (multiple occurrences).

Thanks.
---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

Re: UID/GID override on CIFS mounts to Samba and proposed new mount parameter to disable Unix Extensions on the client

[Steve French]

OK - I fixed the formatting and checked into the cifs-2.6.git tree.  I
also fixed
a few dozen similar errors in formatting in the same files.

Thanks for noticing that.

On 4/30/07, Randy Dunlap <randy.dunlap@oracle.com> wrote:
> On Mon, 30 Apr 2007 09:26:16 -0500 Steve French wrote:
>
> replying to the inline patch  :(
>
> Use a space between "if" and "("   (multiple occurrences).
>
> Thanks.
> ---
> ~Randy
> *** Remember to use Documentation/SubmitChecklist when testing your code ***
>


-- 
Thanks,

Steve