Message-id: <1370653763.3600.55.camel@kjgkr>
Subject: Re: [PATCH 2/2 v2] f2fs: support xattr security labels
From: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Reply-to: jaegeuk.kim@samsung.com
To: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net
Date: Sat, 08 Jun 2013 10:09:23 +0900
In-reply-to: <1370592580.3600.42.camel@kjgkr>
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Change log from v2:
 o fix description and simplify a code line (commented by Casey
Schaufler)

Change log from v1:
 o fix a bug

=46rom 9f889afcd74a58d9a538fa02f4af31d11eb17c54 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Date: Mon, 3 Jun 2013 19:46:19 +0900
Subject: [PATCH] f2fs: support xattr security labels
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs=
-devel@lists.sourceforge.net

This patch adds the support of security labels for f2fs, which will be used
by Linus Security Models (LSMs).

Quote from http://en.wikipedia.org/wiki/Linux_Security_Modules:
"Linux Security Modules (LSM) is a framework that allows the Linux kernel t=
o
support a variety of computer security models while avoiding favoritism tow=
ard
any single security implementation. The framework is licensed under the ter=
ms of
the GNU General Public License and is standard part of the Linux kernel sin=
ce
Linux 2.6. AppArmor, SELinux, Smack and TOMOYO Linux are the currently acce=
pted
modules in the official kernel.".

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
---
 fs/f2fs/Kconfig | 12 +++++++++++
 fs/f2fs/dir.c   |  5 +++++
 fs/f2fs/xattr.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++=
+---
 fs/f2fs/xattr.h | 12 ++++++++++-
 4 files changed, 87 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
index fd27e7e..e06e099 100644
--- a/fs/f2fs/Kconfig
+++ b/fs/f2fs/Kconfig
@@ -51,3 +51,15 @@ config F2FS_FS_POSIX_ACL
 	  Linux website <http://acl.bestbits.at/>.
=20
 	  If you don't know what Access Control Lists are, say N
+
+config F2FS_FS_SECURITY
+	bool "F2FS Security Labels"
+	depends on F2FS_FS_XATTR
+	help
+	  Security labels provide an access control facility to support Linux
+	  Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
+	  Linux. This option enables an extended attribute handler for file
+	  security labels in the f2fs filesystem, so that it requires enabling
+	  the extended attribute support in advance.
+
+	  If you are not using a security module, say N.
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 67e2d13..81a1d6f 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -13,6 +13,7 @@
 #include "f2fs.h"
 #include "node.h"
 #include "acl.h"
+#include "xattr.h"
=20
 static unsigned long dir_blocks(struct inode *inode)
 {
@@ -334,6 +335,10 @@ static struct page *init_inode_metadata(struct inode *=
inode,
 		if (err)
 			goto error;
=20
+		err =3D f2fs_init_security(inode, dir, name);
+		if (err)
+			goto error;
+
 		wait_on_page_writeback(page);
 	} else {
 		page =3D get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index ae61f35..c06e8a3 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -20,6 +20,7 @@
  */
 #include <linux/rwsem.h>
 #include <linux/f2fs_fs.h>
+#include <linux/security.h>
 #include "f2fs.h"
 #include "xattr.h"
=20
@@ -43,6 +44,10 @@ static size_t f2fs_xattr_generic_list(struct dentry *den=
try, char *list,
 		prefix =3D XATTR_TRUSTED_PREFIX;
 		prefix_len =3D XATTR_TRUSTED_PREFIX_LEN;
 		break;
+	case F2FS_XATTR_INDEX_SECURITY:
+		prefix =3D XATTR_SECURITY_PREFIX;
+		prefix_len =3D XATTR_SECURITY_PREFIX_LEN;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -50,7 +55,7 @@ static size_t f2fs_xattr_generic_list(struct dentry *dent=
ry, char *list,
 	total_len =3D prefix_len + name_len + 1;
 	if (list && total_len <=3D list_size) {
 		memcpy(list, prefix, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
+		memcpy(list + prefix_len, name, name_len);
 		list[prefix_len + name_len] =3D '\0';
 	}
 	return total_len;
@@ -70,13 +75,14 @@ static int f2fs_xattr_generic_get(struct dentry *dentry=
, const char *name,
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		break;
+	case F2FS_XATTR_INDEX_SECURITY:
+		break;
 	default:
 		return -EINVAL;
 	}
 	if (strcmp(name, "") =3D=3D 0)
 		return -EINVAL;
-	return f2fs_getxattr(dentry->d_inode, type, name,
-			buffer, size);
+	return f2fs_getxattr(dentry->d_inode, type, name, buffer, size);
 }
=20
 static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
@@ -93,6 +99,8 @@ static int f2fs_xattr_generic_set(struct dentry *dentry, =
const char *name,
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		break;
+	case F2FS_XATTR_INDEX_SECURITY:
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -145,6 +153,40 @@ static int f2fs_xattr_advise_set(struct dentry *dentry=
, const char *name,
 	return 0;
 }
=20
+#ifdef CONFIG_F2FS_FS_SECURITY
+static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_=
array,
+		void *fs_info)
+{
+	const struct xattr *xattr;
+	char *name;
+	int err =3D 0;
+
+	for (xattr =3D xattr_array; xattr->name !=3D NULL; xattr++) {
+		name =3D kmalloc(XATTR_SECURITY_PREFIX_LEN +
+			       strlen(xattr->name) + 1, GFP_NOFS);
+		if (!name) {
+			err =3D -ENOMEM;
+			break;
+		}
+		strcpy(name, XATTR_SECURITY_PREFIX);
+		sprintf(name, XATTR_SECURITY_PREFIX "%s", xattr->name);
+		err =3D f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY, name,
+					xattr->value, xattr->value_len);
+		kfree(name);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
+int f2fs_init_security(struct inode *inode, struct inode *dir,
+				const struct qstr *qstr)
+{
+	return security_inode_init_security(inode, dir, qstr,
+				&f2fs_initxattrs, NULL);
+}
+#endif
+
 const struct xattr_handler f2fs_xattr_user_handler =3D {
 	.prefix	=3D XATTR_USER_PREFIX,
 	.flags	=3D F2FS_XATTR_INDEX_USER,
@@ -169,6 +211,14 @@ const struct xattr_handler f2fs_xattr_advise_handler =
=3D {
 	.set    =3D f2fs_xattr_advise_set,
 };
=20
+const struct xattr_handler f2fs_xattr_security_handler =3D {
+	.prefix	=3D XATTR_SECURITY_PREFIX,
+	.flags	=3D F2FS_XATTR_INDEX_SECURITY,
+	.list	=3D f2fs_xattr_generic_list,
+	.get	=3D f2fs_xattr_generic_get,
+	.set	=3D f2fs_xattr_generic_set,
+};
+
 static const struct xattr_handler *f2fs_xattr_handler_map[] =3D {
 	[F2FS_XATTR_INDEX_USER] =3D &f2fs_xattr_user_handler,
 #ifdef CONFIG_F2FS_FS_POSIX_ACL
@@ -176,6 +226,9 @@ static const struct xattr_handler *f2fs_xattr_handler_m=
ap[] =3D {
 	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] =3D &f2fs_xattr_acl_default_handler,
 #endif
 	[F2FS_XATTR_INDEX_TRUSTED] =3D &f2fs_xattr_trusted_handler,
+#ifdef CONFIG_F2FS_FS_SECURITY
+	[F2FS_XATTR_INDEX_SECURITY] =3D &f2fs_xattr_security_handler,
+#endif
 	[F2FS_XATTR_INDEX_ADVISE] =3D &f2fs_xattr_advise_handler,
 };
=20
@@ -186,6 +239,9 @@ const struct xattr_handler *f2fs_xattr_handlers[] =3D {
 	&f2fs_xattr_acl_default_handler,
 #endif
 	&f2fs_xattr_trusted_handler,
+#ifdef CONFIG_F2FS_FS_SECURITY
+	&f2fs_xattr_security_handler,
+#endif
 	&f2fs_xattr_advise_handler,
 	NULL,
 };
diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h
index 49c9558..14e1329 100644
--- a/fs/f2fs/xattr.h
+++ b/fs/f2fs/xattr.h
@@ -112,6 +112,7 @@ extern const struct xattr_handler f2fs_xattr_trusted_ha=
ndler;
 extern const struct xattr_handler f2fs_xattr_acl_access_handler;
 extern const struct xattr_handler f2fs_xattr_acl_default_handler;
 extern const struct xattr_handler f2fs_xattr_advise_handler;
+extern const struct xattr_handler f2fs_xattr_security_handler;
=20
 extern const struct xattr_handler *f2fs_xattr_handlers[];
=20
@@ -121,7 +122,6 @@ extern int f2fs_getxattr(struct inode *inode, int name_=
index, const char *name,
 		void *buffer, size_t buffer_size);
 extern ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
 		size_t buffer_size);
-
 #else
=20
 #define f2fs_xattr_handlers	NULL
@@ -142,4 +142,14 @@ static inline ssize_t f2fs_listxattr(struct dentry *de=
ntry, char *buffer,
 }
 #endif
=20
+#ifdef CONFIG_F2FS_FS_SECURITY
+extern int f2fs_init_security(struct inode *inode, struct inode *dir,
+				const struct qstr *qstr);
+#else
+static inline int f2fs_init_security(struct inode *inode, struct inode *di=
r,
+				const struct qstr *qstr)
+{
+	return 0;
+}
+#endif
 #endif /* __F2FS_XATTR_H__ */
--=20
1.8.1.3.566.gaa39828


--=20
Jaegeuk Kim
Samsung

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