security: new security_inode_init_security API adds function callback

This patch changes the security_inode_init_security API by adding a
filesystem specific callback to write security extended attributes.
This change is in preparation for supporting the initialization of
multiple LSM xattrs and the EVM xattr. Initially the callback function
walks an array of xattrs, writing each xattr separately, but could be
optimized to write multiple xattrs at once.

For existing security_inode_init_security() calls, which have not yet
been converted to use the new callback function, such as those in
reiserfs and ocfs2, this patch defines security_old_inode_init_security().

Signed-off-by: Mimi Zohar <[e-mail]>

fs/btrfs/xattr.c

···
 				XATTR_REPLACE);
 }
 
+int btrfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		     void *fs_info)
+{
+	const struct xattr *xattr;
+	struct btrfs_trans_handle *trans = fs_info;
+	char *name;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
+			       strlen(xattr->name) + 1, GFP_NOFS);
+		if (!name) {
+			err = -ENOMEM;
+			break;
+		}
+		strcpy(name, XATTR_SECURITY_PREFIX);
+		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
+		err = __btrfs_setxattr(trans, inode, name,
+				       xattr->value, xattr->value_len, 0);
+		kfree(name);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
 int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
 			      struct inode *inode, struct inode *dir,
 			      const struct qstr *qstr)
 {
-	int err;
-	size_t len;
-	void *value;
-	char *suffix;
-	char *name;
-
-	err = security_inode_init_security(inode, dir, qstr, &suffix, &value,
-					   &len);
-	if (err) {
-		if (err == -EOPNOTSUPP)
-			return 0;
-		return err;
-	}
-
-	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
-		       GFP_NOFS);
-	if (!name) {
-		err = -ENOMEM;
-	} else {
-		strcpy(name, XATTR_SECURITY_PREFIX);
-		strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
-		err = __btrfs_setxattr(trans, inode, name, value, len, 0);
-		kfree(name);
-	}
-
-	kfree(suffix);
-	kfree(value);
-	return err;
+	return security_inode_init_security(inode, dir, qstr,
+					    &btrfs_initxattrs, trans);
 }

fs/ext2/xattr_security.c

···
 			      value, size, flags);
 }
 
+int ext2_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		    void *fs_info)
+{
+	const struct xattr *xattr;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY,
+				     xattr->name, xattr->value,
+				     xattr->value_len, 0);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
 int
 ext2_init_security(struct inode *inode, struct inode *dir,
 		   const struct qstr *qstr)
 {
-	int err;
-	size_t len;
-	void *value;
-	char *name;
-
-	err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
-	if (err) {
-		if (err == -EOPNOTSUPP)
-			return 0;
-		return err;
-	}
-	err = ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY,
-			     name, value, len, 0);
-	kfree(name);
-	kfree(value);
-	return err;
+	return security_inode_init_security(inode, dir, qstr,
+					    &ext2_initxattrs, NULL);
 }
 
 const struct xattr_handler ext2_xattr_security_handler = {

fs/ext3/xattr_security.c

···
 			      name, value, size, flags);
 }
 
+int ext3_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		    void *fs_info)
+{
+	const struct xattr *xattr;
+	handle_t *handle = fs_info;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = ext3_xattr_set_handle(handle, inode,
+					    EXT3_XATTR_INDEX_SECURITY,
+					    xattr->name, xattr->value,
+					    xattr->value_len, 0);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
 int
 ext3_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
 		   const struct qstr *qstr)
 {
-	int err;
-	size_t len;
-	void *value;
-	char *name;
-
-	err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
-	if (err) {
-		if (err == -EOPNOTSUPP)
-			return 0;
-		return err;
-	}
-	err = ext3_xattr_set_handle(handle, inode, EXT3_XATTR_INDEX_SECURITY,
-				    name, value, len, 0);
-	kfree(name);
-	kfree(value);
-	return err;
+	return security_inode_init_security(inode, dir, qstr,
+					    &ext3_initxattrs, handle);
 }
 
 const struct xattr_handler ext3_xattr_security_handler = {

fs/ext4/xattr_security.c

···
 			      name, value, size, flags);
 }
 
+int ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		    void *fs_info)
+{
+	const struct xattr *xattr;
+	handle_t *handle = fs_info;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = ext4_xattr_set_handle(handle, inode,
+					    EXT4_XATTR_INDEX_SECURITY,
+					    xattr->name, xattr->value,
+					    xattr->value_len, 0);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
 int
 ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
 		   const struct qstr *qstr)
 {
-	int err;
-	size_t len;
-	void *value;
-	char *name;
-
-	err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
-	if (err) {
-		if (err == -EOPNOTSUPP)
-			return 0;
-		return err;
-	}
-	err = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_SECURITY,
-				    name, value, len, 0);
-	kfree(name);
-	kfree(value);
-	return err;
+	return security_inode_init_security(inode, dir, qstr,
+					    &ext4_initxattrs, handle);
 }
 
 const struct xattr_handler ext4_xattr_security_handler = {

fs/gfs2/inode.c

···
 	return error;
 }
 
+int gfs2_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		    void *fs_info)
+{
+	const struct xattr *xattr;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = __gfs2_xattr_set(inode, xattr->name, xattr->value,
+				       xattr->value_len, 0,
+				       GFS2_EATYPE_SECURITY);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
 static int gfs2_security_init(struct gfs2_inode *dip, struct gfs2_inode *ip,
 			      const struct qstr *qstr)
 {
-	int err;
-	size_t len;
-	void *value;
-	char *name;
-
-	err = security_inode_init_security(&ip->i_inode, &dip->i_inode, qstr,
-					   &name, &value, &len);
-
-	if (err) {
-		if (err == -EOPNOTSUPP)
-			return 0;
-		return err;
-	}
-
-	err = __gfs2_xattr_set(&ip->i_inode, name, value, len, 0,
-			       GFS2_EATYPE_SECURITY);
-	kfree(value);
-	kfree(name);
-
-	return err;
+	return security_inode_init_security(&ip->i_inode, &dip->i_inode, qstr,
+					    &gfs2_initxattrs, NULL);
 }
 
 /**

fs/jffs2/security.c

···
 #include <linux/security.h>
 #include "nodelist.h"
 
-/* ---- Initial Security Label Attachment -------------- */
+/* ---- Initial Security Label(s) Attachment callback --- */
+int jffs2_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		     void *fs_info)
+{
+	const struct xattr *xattr;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = do_jffs2_setxattr(inode, JFFS2_XPREFIX_SECURITY,
+					xattr->name, xattr->value,
+					xattr->value_len, 0);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
+/* ---- Initial Security Label(s) Attachment ----------- */
 int jffs2_init_security(struct inode *inode, struct inode *dir,
 			const struct qstr *qstr)
 {
-	int rc;
-	size_t len;
-	void *value;
-	char *name;
-
-	rc = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
-	if (rc) {
-		if (rc == -EOPNOTSUPP)
-			return 0;
-		return rc;
-	}
-	rc = do_jffs2_setxattr(inode, JFFS2_XPREFIX_SECURITY, name, value, len, 0);
-
-	kfree(name);
-	kfree(value);
-	return rc;
+	return security_inode_init_security(inode, dir, qstr,
+					    &jffs2_initxattrs, NULL);
 }
 
 /* ---- XATTR Handler for "security.*" ----------------- */

fs/jfs/xattr.c

···
 }
 
 #ifdef CONFIG_JFS_SECURITY
+int jfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		   void *fs_info)
+{
+	const struct xattr *xattr;
+	tid_t *tid = fs_info;
+	char *name;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
+			       strlen(xattr->name) + 1, GFP_NOFS);
+		if (!name) {
+			err = -ENOMEM;
+			break;
+		}
+		strcpy(name, XATTR_SECURITY_PREFIX);
+		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
+
+		err = __jfs_setxattr(*tid, inode, name,
+				     xattr->value, xattr->value_len, 0);
+		kfree(name);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
 int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir,
 		      const struct qstr *qstr)
 {
-	int rc;
-	size_t len;
-	void *value;
-	char *suffix;
-	char *name;
-
-	rc = security_inode_init_security(inode, dir, qstr, &suffix, &value,
-					  &len);
-	if (rc) {
-		if (rc == -EOPNOTSUPP)
-			return 0;
-		return rc;
-	}
-	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + 1 + strlen(suffix),
-		       GFP_NOFS);
-	if (!name) {
-		rc = -ENOMEM;
-		goto kmalloc_failed;
-	}
-	strcpy(name, XATTR_SECURITY_PREFIX);
-	strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
-
-	rc = __jfs_setxattr(tid, inode, name, value, len, 0);
-
-	kfree(name);
-kmalloc_failed:
-	kfree(suffix);
-	kfree(value);
-
-	return rc;
+	return security_inode_init_security(inode, dir, qstr,
+					    &jfs_initxattrs, &tid);
 }
 #endif

fs/ocfs2/xattr.c

···
 {
 	int ret = 0;
 	struct buffer_head *dir_bh = NULL;
-	struct ocfs2_security_xattr_info si = {
-		.enable = 1,
-	};
 
-	ret = ocfs2_init_security_get(inode, dir, qstr, &si);
+	ret = ocfs2_init_security_get(inode, dir, qstr, NULL);
 	if (!ret) {
-		ret = ocfs2_xattr_set(inode, OCFS2_XATTR_INDEX_SECURITY,
-				      si.name, si.value, si.value_len,
-				      XATTR_CREATE);
-		if (ret) {
-			mlog_errno(ret);
-			goto leave;
-		}
-	} else if (ret != -EOPNOTSUPP) {
 		mlog_errno(ret);
 		goto leave;
 	}
···
 			       name, value, size, flags);
 }
 
+int ocfs2_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		     void *fs_info)
+{
+	const struct xattr *xattr;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = ocfs2_xattr_set(inode, OCFS2_XATTR_INDEX_SECURITY,
+				      xattr->name, xattr->value,
+				      xattr->value_len, XATTR_CREATE);
+		if (err)
+			break;
+	}
+	return err;
+}
+
 int ocfs2_init_security_get(struct inode *inode,
 			    struct inode *dir,
 			    const struct qstr *qstr,
···
 	/* check whether ocfs2 support feature xattr */
 	if (!ocfs2_supports_xattr(OCFS2_SB(dir->i_sb)))
 		return -EOPNOTSUPP;
-	return security_inode_init_security(inode, dir, qstr, &si->name,
-					    &si->value, &si->value_len);
+	if (si)
+		return security_old_inode_init_security(inode, dir, qstr,
+							&si->name, &si->value,
+							&si->value_len);
+
+	return security_inode_init_security(inode, dir, qstr,
+					    &ocfs2_initxattrs, NULL);
 }
 
 int ocfs2_init_security_set(handle_t *handle,

fs/reiserfs/xattr_security.c

···
 	if (IS_PRIVATE(dir))
 		return 0;
 
-	error = security_inode_init_security(inode, dir, qstr, &sec->name,
-					     &sec->value, &sec->length);
+	error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
+						 &sec->value, &sec->length);
 	if (error) {
 		if (error == -EOPNOTSUPP)
 			error = 0;

fs/xfs/linux-2.6/xfs_iops.c

···
 		mark_inode_dirty(inode);
 }
 
+
+int xfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		   void *fs_info)
+{
+	const struct xattr *xattr;
+	struct xfs_inode *ip = XFS_I(inode);
+	int error = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		error = xfs_attr_set(ip, xattr->name, xattr->value,
+				     xattr->value_len, ATTR_SECURE);
+		if (error < 0)
+			break;
+	}
+	return error;
+}
+
 /*
  * Hook in SELinux.  This is not quite correct yet, what we really need
  * here (as we do for default ACLs) is a mechanism by which creation of
  * these attrs can be journalled at inode creation time (along with the
  * inode, of course, such that log replay can't cause these to be lost).
  */
+
 STATIC int
 xfs_init_security(
 	struct inode	*inode,
 	struct inode	*dir,
 	const struct qstr *qstr)
 {
-	struct xfs_inode *ip = XFS_I(inode);
-	size_t		length;
-	void		*value;
-	unsigned char	*name;
-	int		error;
-
-	error = security_inode_init_security(inode, dir, qstr, (char **)&name,
-					     &value, &length);
-	if (error) {
-		if (error == -EOPNOTSUPP)
-			return 0;
-		return -error;
-	}
-
-	error = xfs_attr_set(ip, name, value, length, ATTR_SECURE);
-
-	kfree(name);
-	kfree(value);
-	return error;
+	return security_inode_init_security(inode, dir, qstr,
+					    &xfs_initxattrs, NULL);
 }
 
 static void

include/linux/security.h

···
 #include <linux/key.h>
 #include <linux/xfrm.h>
 #include <linux/slab.h>
+#include <linux/xattr.h>
 #include <net/flow.h>
 
 /* Maximum number of letters for an LSM name string */
···
 extern int mmap_min_addr_handler(struct ctl_table *table, int write,
 				 void __user *buffer, size_t *lenp, loff_t *ppos);
 #endif
+
+/* security_inode_init_security callback function to write xattrs */
+typedef int (*initxattrs) (struct inode *inode,
+			   const struct xattr *xattr_array, void *fs_data);
 
 #ifdef CONFIG_SECURITY
 
···
 int security_inode_alloc(struct inode *inode);
 void security_inode_free(struct inode *inode);
 int security_inode_init_security(struct inode *inode, struct inode *dir,
-				 const struct qstr *qstr, char **name,
-				 void **value, size_t *len);
+				 const struct qstr *qstr,
+				 initxattrs initxattrs, void *fs_data);
+int security_old_inode_init_security(struct inode *inode, struct inode *dir,
+				     const struct qstr *qstr, char **name,
+				     void **value, size_t *len);
 int security_inode_create(struct inode *dir, struct dentry *dentry, int mode);
 int security_inode_link(struct dentry *old_dentry, struct inode *dir,
 			 struct dentry *new_dentry);
···
 static inline int security_inode_init_security(struct inode *inode,
 						struct inode *dir,
 						const struct qstr *qstr,
-						char **name,
-						void **value,
-						size_t *len)
+						initxattrs initxattrs,
+						void *fs_data)
 {
 	return -EOPNOTSUPP;
 }

include/linux/xattr.h

···
 		   size_t size, int flags, int handler_flags);
 };
 
+struct xattr {
+	char *name;
+	void *value;
+	size_t value_len;
+};
+
 ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);

mm/shmem.c

···
 	inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
 	if (inode) {
 		error = security_inode_init_security(inode, dir,
-						     &dentry->d_name, NULL,
+						     &dentry->d_name,
 						     NULL, NULL);
 		if (error) {
 			if (error != -EOPNOTSUPP) {
···
 	if (!inode)
 		return -ENOSPC;
 
-	error = security_inode_init_security(inode, dir, &dentry->d_name, NULL,
+	error = security_inode_init_security(inode, dir, &dentry->d_name,
 					     NULL, NULL);
 	if (error) {
 		if (error != -EOPNOTSUPP) {

security/security.c

···
 #include <linux/security.h>
 #include <linux/ima.h>
 
+#define MAX_LSM_XATTR	1
+
 /* Boot-time LSM user choice */
 static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
 	CONFIG_DEFAULT_SECURITY;
···
 }
 
 int security_inode_init_security(struct inode *inode, struct inode *dir,
-				 const struct qstr *qstr, char **name,
-				 void **value, size_t *len)
+				 const struct qstr *qstr,
+				 const initxattrs initxattrs, void *fs_data)
+{
+	struct xattr new_xattrs[MAX_LSM_XATTR + 1];
+	struct xattr *lsm_xattr;
+	int ret;
+
+	if (unlikely(IS_PRIVATE(inode)))
+		return -EOPNOTSUPP;
+
+	memset(new_xattrs, 0, sizeof new_xattrs);
+	if (!initxattrs)
+		return security_ops->inode_init_security(inode, dir, qstr,
+							 NULL, NULL, NULL);
+	lsm_xattr = new_xattrs;
+	ret = security_ops->inode_init_security(inode, dir, qstr,
+						&lsm_xattr->name,
+						&lsm_xattr->value,
+						&lsm_xattr->value_len);
+	if (ret)
+		goto out;
+	ret = initxattrs(inode, new_xattrs, fs_data);
+out:
+	kfree(lsm_xattr->name);
+	kfree(lsm_xattr->value);
+
+	return (ret == -EOPNOTSUPP) ? 0 : ret;
+}
+EXPORT_SYMBOL(security_inode_init_security);
+
+int security_old_inode_init_security(struct inode *inode, struct inode *dir,
+				     const struct qstr *qstr, char **name,
+				     void **value, size_t *len)
 {
 	if (unlikely(IS_PRIVATE(inode)))
 		return -EOPNOTSUPP;
 	return security_ops->inode_init_security(inode, dir, qstr, name, value,
 						 len);
 }
-EXPORT_SYMBOL(security_inode_init_security);
+EXPORT_SYMBOL(security_old_inode_init_security);
 
 #ifdef CONFIG_SECURITY_PATH
 int security_path_mknod(struct path *dir, struct dentry *dentry, int mode,