fs/9p: xattr: add trusted and security namespaces

Allow requests for security.* and trusted.* xattr name spaces
to pass through to server.

The new files are 99% cut and paste from fs/9p/xattr_user.c with the
namespaces changed.  It has the intended effect in superficial testing.
I do not know much detail about how these namespaces are used, but passing
them through to the server, which can decide whether to handle them or not,
seems reasonable.

I want to support a use case where an ext4 file system is mounted via 9P,
then re-exported via samba to windows clients in a cluster.  Windows wants
to store xattrs such as security.NTACL.  This works when ext4 directly
backs samba, but not when 9P is inserted.  This use case is documented here:
   http://code.google.com/p/diod/issues/detail?id=95

Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

diff --git a/fs/9p/Kconfig b/fs/9p/Kconfig
index 55abfd6..6489e1f 100644 (file)
--- a/fs/9p/Kconfig
+++ b/fs/9p/Kconfig
@@ -31,3 +31,16 @@ config 9P_FS_POSIX_ACL
          If you don't know what Access Control Lists are, say N
 
 endif
+
+
+config 9P_FS_SECURITY
+        bool "9P Security Labels"
+        depends on 9P_FS
+        help
+          Security labels support alternative access control models
+          implemented by security modules like SELinux.  This option
+          enables an extended attribute handler for file security
+          labels in the 9P filesystem.
+
+          If you are not using a security module that requires using
+          extended attributes for file security labels, say N.

diff --git a/fs/9p/Makefile b/fs/9p/Makefile
index ab8c127..ff7be98 100644 (file)
--- a/fs/9p/Makefile
+++ b/fs/9p/Makefile
@@ -11,7 +11,9 @@ obj-$(CONFIG_9P_FS) := 9p.o
        v9fs.o \
        fid.o  \
        xattr.o \
-       xattr_user.o
+       xattr_user.o \
+       xattr_trusted.o
 
 9p-$(CONFIG_9P_FSCACHE) += cache.o
 9p-$(CONFIG_9P_FS_POSIX_ACL) += acl.o
+9p-$(CONFIG_9P_FS_SECURITY) += xattr_security.o

diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index c45e016..3c28cdf 100644 (file)
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -167,9 +167,13 @@ ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 
 const struct xattr_handler *v9fs_xattr_handlers[] = {
        &v9fs_xattr_user_handler,
+       &v9fs_xattr_trusted_handler,
 #ifdef CONFIG_9P_FS_POSIX_ACL
        &v9fs_xattr_acl_access_handler,
        &v9fs_xattr_acl_default_handler,
 #endif
+#ifdef CONFIG_9P_FS_SECURITY
+       &v9fs_xattr_security_handler,
+#endif
        NULL
 };

diff --git a/fs/9p/xattr.h b/fs/9p/xattr.h
index eec348a..d3e2ea3 100644 (file)
--- a/fs/9p/xattr.h
+++ b/fs/9p/xattr.h
@@ -20,6 +20,8 @@
 
 extern const struct xattr_handler *v9fs_xattr_handlers[];
 extern struct xattr_handler v9fs_xattr_user_handler;
+extern struct xattr_handler v9fs_xattr_trusted_handler;
+extern struct xattr_handler v9fs_xattr_security_handler;
 extern const struct xattr_handler v9fs_xattr_acl_access_handler;
 extern const struct xattr_handler v9fs_xattr_acl_default_handler;
 

diff --git a/fs/9p/xattr_security.c b/fs/9p/xattr_security.c
new file mode 100644 (file)
index 0000000..cb247a1
--- /dev/null
+++ b/fs/9p/xattr_security.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include "xattr.h"
+
+static int v9fs_xattr_security_get(struct dentry *dentry, const char *name,
+                       void *buffer, size_t size, int type)
+{
+       int retval;
+       char *full_name;
+       size_t name_len;
+       size_t prefix_len = XATTR_SECURITY_PREFIX_LEN;
+
+       if (name == NULL)
+               return -EINVAL;
+
+       if (strcmp(name, "") == 0)
+               return -EINVAL;
+
+       name_len = strlen(name);
+       full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+       if (!full_name)
+               return -ENOMEM;
+       memcpy(full_name, XATTR_SECURITY_PREFIX, prefix_len);
+       memcpy(full_name+prefix_len, name, name_len);
+       full_name[prefix_len + name_len] = '\0';
+
+       retval = v9fs_xattr_get(dentry, full_name, buffer, size);
+       kfree(full_name);
+       return retval;
+}
+
+static int v9fs_xattr_security_set(struct dentry *dentry, const char *name,
+                       const void *value, size_t size, int flags, int type)
+{
+       int retval;
+       char *full_name;
+       size_t name_len;
+       size_t prefix_len = XATTR_SECURITY_PREFIX_LEN;
+
+       if (name == NULL)
+               return -EINVAL;
+
+       if (strcmp(name, "") == 0)
+               return -EINVAL;
+
+       name_len = strlen(name);
+       full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+       if (!full_name)
+               return -ENOMEM;
+       memcpy(full_name, XATTR_SECURITY_PREFIX, prefix_len);
+       memcpy(full_name + prefix_len, name, name_len);
+       full_name[prefix_len + name_len] = '\0';
+
+       retval = v9fs_xattr_set(dentry, full_name, value, size, flags);
+       kfree(full_name);
+       return retval;
+}
+
+struct xattr_handler v9fs_xattr_security_handler = {
+       .prefix = XATTR_SECURITY_PREFIX,
+       .get    = v9fs_xattr_security_get,
+       .set    = v9fs_xattr_security_set,
+};

diff --git a/fs/9p/xattr_trusted.c b/fs/9p/xattr_trusted.c
new file mode 100644 (file)
index 0000000..e30d33b
--- /dev/null
+++ b/fs/9p/xattr_trusted.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include "xattr.h"
+
+static int v9fs_xattr_trusted_get(struct dentry *dentry, const char *name,
+                       void *buffer, size_t size, int type)
+{
+       int retval;
+       char *full_name;
+       size_t name_len;
+       size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+
+       if (name == NULL)
+               return -EINVAL;
+
+       if (strcmp(name, "") == 0)
+               return -EINVAL;
+
+       name_len = strlen(name);
+       full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+       if (!full_name)
+               return -ENOMEM;
+       memcpy(full_name, XATTR_TRUSTED_PREFIX, prefix_len);
+       memcpy(full_name+prefix_len, name, name_len);
+       full_name[prefix_len + name_len] = '\0';
+
+       retval = v9fs_xattr_get(dentry, full_name, buffer, size);
+       kfree(full_name);
+       return retval;
+}
+
+static int v9fs_xattr_trusted_set(struct dentry *dentry, const char *name,
+                       const void *value, size_t size, int flags, int type)
+{
+       int retval;
+       char *full_name;
+       size_t name_len;
+       size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+
+       if (name == NULL)
+               return -EINVAL;
+
+       if (strcmp(name, "") == 0)
+               return -EINVAL;
+
+       name_len = strlen(name);
+       full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+       if (!full_name)
+               return -ENOMEM;
+       memcpy(full_name, XATTR_TRUSTED_PREFIX, prefix_len);
+       memcpy(full_name + prefix_len, name, name_len);
+       full_name[prefix_len + name_len] = '\0';
+
+       retval = v9fs_xattr_set(dentry, full_name, value, size, flags);
+       kfree(full_name);
+       return retval;
+}
+
+struct xattr_handler v9fs_xattr_trusted_handler = {
+       .prefix = XATTR_TRUSTED_PREFIX,
+       .get    = v9fs_xattr_trusted_get,
+       .set    = v9fs_xattr_trusted_set,
+};